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	claims	1. A method of exposing a field on a target by means of a plurality of charged particle beamlets, the method comprising:providing a plurality of beamlets, the beamlets being generated by one or more aperture arrays having apertures arranged in a two-dimensional array to produce a plurality of groups of beamlets;providing a target to be exposed, the target comprising the field;creating relative movement in a first direction between the plurality of beamlets and the target;deflecting the plurality of beamlets in a second direction simultaneously with the relative movement in the first direction, such that each beamlet exposes a plurality of parallel scan lines on the target;wherein different groups of beamlets expose a different single stripe of the field in the first direction, each stripe having a length as long as the field in the first direction, and the beamlets of each croup of beamlets expose the full stripe width, andwherein the relative movement in the first direction and the deflection of the plurality of beamlets in the second direction are such that the distance between adjacent parallel scan lines exposed by the plurality of beamlets is smaller than a pitch between beamlets of the plurality of beamlets in the array. 2. The method according to claim 1, wherein the distance between adjacent scan lines exposed by the plurality of beamlets equals the projection pitch Pproj,X divided by K, where K is a positive integer larger than one. 3. The method according to claim 2, wherein K equals a factor of the number of beamlets in the array minus one. 4. The method according to claim 1, wherein the distance between subsequent scan lines exposed by the same beamlet within the array of beamlets is smaller than the projected size of the array in the first direction. 5. The method according to claim 4, wherein the distance between subsequent scan lines exposed by the same beamlet within the array of beamlets equals N F N - 1 ⁢ P proj , X ,whereFN−1 is a factor of (N−1) unequal to one, and N is the number of beamlets in the array. 6. The method according to claim 1, wherein the method further comprises defining a virtual grid over the target, the grid providing positions of exposing or not exposing the target by respective beamlets, the exposure or non-exposure in dependence of a blanking or a non blanking of each individual beamlet. 7. The method according to claim 6, wherein the virtual grid comprises a first axis being oriented in line with the first direction, and a second axis being oriented transverse thereto. 8. The method according to claim 6, wherein the plurality of beamlets are divided in groups, each group of beamlets being arranged in an array, such that the beamlets of the group do not overlap, the array of beamlets thereby corresponding to an array of locations in the grid. 9. The method according to claim 1, wherein a projection pitch Pproj,X in the first direction between beamlets of the array is equal to or smaller than a beamlet spot size as projected on the target. 10. A method of exposing a target by means of a plurality of beamlets, the method comprising:providing a plurality of beamlets, the beamlets being arranged in a two-dimensional array;providing a target to be exposed;creating relative movement in a first direction between the plurality of beamlets and the target;deflecting the plurality of beamlets in a second direction in a plurality of scans such that each beamlet exposes a plurality of parallel scan lines on the target;wherein different groups of beamlets expose a different single stripe of the field in the first direction, each stripe having a length as long as the field in the first direction, and the beamlets of each group of beamlets expose the full stripe width, andwherein the relative movement in the first direction and the deflection of the plurality of beamlets in the second direction are such that the distance between subsequent scan lines exposed by the same beamlet within the array of beamlets is smaller than the projected size of the array in the first direction, so that scan lines of one or more beamlets from a second scan are interleaved with scan lines of one or more beamlets from a first scan. 11. The method according to claim 10, wherein the distance between subsequent scan lines exposed by the same beamlet within the array of beamlets equals N F N - 1 ⁢ P proj , X ,wherePproj,X is a projection pitch in the first direction between beamlets of the array, and FN−1 is a factor of (N−1) unequal to one, and N is the number of beamlets in the array. 12. The method according to claim 11, wherein the relative movement in the first direction has a constant velocity. 13. The method according to claim 11, wherein the deflection in the second direction is a repetitive deflection having a constant frequency. 14. A charged particle multi-beamlet system for exposing a target using a plurality of beamlets, the system comprising:a beamlet pattern generator for providing an exposure pattern formed by a plurality of beamlets, the plurality of beamlets being arranged in groups of beamlets;an array of projection lens systems for projecting the groups of beamlets on to the surface of the target, each projection lens system corresponding with a group of beamlets;a deflector array for deflecting a group of beamlets in a second direction, the deflector array comprising a plurality of deflectors, each deflector arranged to deflect a corresponding group of beamlets;wherein different groups of beamlets expose a different single stripe of the field in the first direction, each stripe having a length as long as the field in the first direction, and the beamlets of each group of beamlets expose the full stripe width, anda substrate support member for supporting the target to be exposed;a control unit arranged to coordinate relative movement between the substrate support member and the plurality of beamlets in a first direction and deflection of the group of beamlets in the second direction such that the distance between adjacent scan lines exposed by the plurality of beamlets is smaller than a projection pitch Pproj, X in the first direction between beamlets of the plurality of beamlets in the array. 15. A charged particle multi-beamlet system according to claim 14, wherein the distance between adjacent scan lines exposed by the plurality of beamlets equals the projection pitch Pproj,X divided by K, where K is a positive integer larger than one. 16. A charged particle multi-beamlet system according to claim 15, wherein K equals a factor of the number of beamlets in the array minus one. 17. A charged particle multi-beamlet system according to claim 14, wherein the distance between subsequent scan lines exposed by the same beamlet within the plurality of beamlets is smaller than the projected size of the array in the first direction. 18. A charged particle multi-beamlet system according to claim 17, wherein the distance between subsequent scan lines exposed by the same beamlet within the array of beamlets equals N F N - 1 ⁢ P proj , X ,where FN−1 is a factor of (N−1) unequal to one, and N is the number of beamlets in the array. 19. A charged particle multi-beamlet system according to claim 14, wherein the projection pitch Pproj,X is equal to or smaller than a beamlet spot size (30) as projected on the target. 20. A charged particle multi-beamlet system according to claim 14, wherein the beamlet pattern generator comprises:at least one charged particle source for generating a charged particle beam;an aperture array defining separate beamlets or sub-beams from the generated beam;a beamlet manipulator for converging groups of beamlets towards a common point of convergence for each group; anda beamlet blanker for controllably blanking beamlets in the groups of beamlets. 21. A charged particle multi-beamlet system according to claim 20, wherein the common point of convergence for each group of beamlets is a point corresponding to one of the projection lens systems. 22. A charged particle multi-beamlet system according to claim 14, wherein the array of beamlets comprises a number of rows and a number of columns, at least one of the rows and columns being positioned at an angle unequal to 90° with respect to the first direction and the second direction. 23. A charged particle multi-beamlet system according to claim 14, wherein the beamlet pattern generator is arranged to provide the exposure pattern by defining a virtual grid over the target, the grid providing positions of exposing or not exposing the target by respective beamlets, the exposure or non-exposure in dependence of a blanking or a non-blanking of each individual beamlet. 24. A charged particle multi-beamlet system according to claim 23, wherein the virtual grid comprises a first axis being oriented in line with the first direction of movement, and a second axis being oriented transverse thereto. 25. A charged particle multi-beamlet system for exposing a target using a plurality of beamlets, the system comprising:a beamlet pattern generator for providing a exposure pattern formed by a plurality of beamlets, the plurality of beamlets being arranged in groups of beamlets;an array of projection lens systems for projecting the groups of beamlets on to the surface of the target, each projection lens system corresponding with a group of beamlets;a deflector array for deflecting a group of beamlets in a second direction, the deflector array comprising a plurality of deflectors, each deflector arranged to deflect a corresponding group of beamlets;wherein different groups of beamlets expose a different single stripe of the field in the first direction, each stripe having a length as long as the field in the first direction, and the beamlets of each group of beamlets expose the full stripe width, anda substrate support member for supporting the target to be exposed;a control unit arranged to coordinate relative movement between the substrate support member and the plurality of beamlets in a first direction and deflection of the group of beamlets in the second direction such that the distance between subsequent scan lines exposed by the same beamlet within the array of beamlets is smaller than the projected size of the array in the first direction. 26. A charged particle multi-beam system according to claim 25, wherein the distance between subsequent scan lines exposed by the same beamlet within the plurality of beamlets equals N F N - 1 ⁢ P proj , X ,where Pproj,X is a projection pitch in the first direction between beamlets of the plurality of beamlets in the array, FN−1 being a factor of (N−1) unequal to one, and N is the number of beamlets in the array. 27. The method according to claim 1, wherein the relative movement in the first direction and the deflection of the plurality of beamlets in the second direction are such that adjacent parallel scan lines are exposed by different beamlets. 28. The method according to claim 10, wherein the relative movement in the first direction and the deflection of the plurality of beamlets in the second direction are such that adjacent parallel scan lines are exposed by different beamlets. 29. A charged particle multi-beamlet system according to claim 14, wherein the control unit is arranged to coordinate relative movement between the substrate support member and the plurality of beamlets in the first direction and deflection of the group of beamlets in the second direction such that adjacent parallel scan lines are exposed by different beamlets. 30. A charged particle multi-beamlet system according to claim 25, wherein the control unit is arranged to coordinate relative movement between the substrate support member and the plurality of beamlets in the first direction and deflection of the group of beamlets in the second direction such that adjacent parallel scan lines are exposed by different beamlets.
055901620	claims	1. A method for powering an electrical circuit inside a nuclear reactor, comprising the steps of: installing an electrical circuit inside a nuclear reactor; selecting an isotopic material which has the property, when placed at a predetermined location within a neutron flux inside the nuclear reactor, or capturing neutrons from the neutron flux and being activated by neutron capture to a radioactive state having a subsequent decay chain during which at least one .beta.-particle is emitted; constructing a .beta.-battery by placing a metallic collector in relationship to a mass of said selected isotopic material so that .beta.-particles emitted by said selected isotopic material are collected; placing said .beta.-battery in an unactivated state at said predetermined location within the neutron-flux; and connecting said .beta.-battery to said electrical circuit. installing an electrical circuit inside a nuclear reactor; selecting an isotopic material which has the property, when placed at a predetermined location within a neutron flux inside the nuclear reactor, of capturing neutrons from the neutron flux and being activated by neutron capture to a radioactive state having a subsequent decay chain during which at least one .beta.-particle is emitted; constructing a .beta.-battery by placing a metallic collector in relationship to a mass of said selected isotopic material so that .beta.-particles emitted by said selected isotopic material are collected; placing said .beta.-battery in an unactivated state at said predetermined location inside the nuclear reactor for a duration of time sufficient to activate said selected isotopic material; moving said activated .beta.-battery to a different location in proximity to said electrical circuit; and connecting said .beta.-battery to said electrical circuit. selecting an isotopic material which has the property, when placed at a predetermined location within a neutron flux inside the nuclear reactor, of capturing neutrons from the neutron flux and being activated by neutron capture to a radioactive state having a subsequent decay chain during which at least one negative .beta.-particle is emitted; constructing a .beta.-battery by placing a metallic collector in relationship to a mass of said selected isotopic material so that negative .beta.-particles emitted by said selected isotopic material are collected; placing said .beta.-battery in an unactivated state at said predetermined location within the neutron flux; and electrically connecting said .beta.-battery and said metal component so that collected negative .beta.-particles flow to said metal component. 2. The method as defined in claim 1, wherein said selected isotopic material is an isotope of thallium. 3. A method for powering an electrical circuit inside a nuclear reactor, comprising the steps of: 4. The method as defined in claim 3, wherein said selected isotopic material is an isotope of thallium. 5. A method for supplying electrical current to a metal alloy component inside a nuclear reactor, comprising the steps of: 6. The method as defined in claim 5, wherein said selected isotopic material is an isotope of thallium.
	abstract	Method and system are disclosed for determining conditions of components that are removably coupled to articles of personal protection equipment (PPE) by tracking the components against predetermined criteria.
061809519	abstract	Irradiation of a target material disposed around a reel rotated about an axis perpendicular to the sweep of a beam of radiation produces a linear relationship between the depth into the target material and the radiation dose received. Where the core of the reel is sufficiently transparent to the radiation beam, target material located on the backside of the reel is also irradiated, creating a constant relationship between depth into the target material and the radiation dose received. The depth/dose profile can be tuned to a constant value by varying parameters of the irradiation process, such as target material thickness, target material density, reel diameter, and energy of the applied beam of radiation.
	abstract	An atom interferometer device for inertial sensing includes one or more thermal atomic sources, a state preparation laser, a set of lasers, and a detection laser. The one or more thermal atomic sources provide one or more atomic beams. A state preparation laser is disposed to provide a state preparation laser beam nominally perpendicular to each of the one or more atomic beams. A set of lasers is disposed to provide interrogation laser beams that interrogate the one or more atomic beams to assist in generating atom interference. A detection laser is disposed to provide a detection laser beam, which is angled at a first angle to the each of the one or more atomic beams in order to enhance the dynamic range of the device by enabling velocity selectivity of atoms used in detecting the atom interference.
	summary
039376524	abstract	In a nuclear power installation comprising a fluid-cooled nuclear reactor, main boilers and main coolant circulators driven by steam turbines to circulate coolant fluid through the reactor core and the main boilers, the circulator-driving steam turbines are driven by steam from auxiliary boilers which are also heated by the hot reactor coolant. This steam, after then being reheated by the hot reactor coolant if desired, may also then drive auxiliary steam turbogenerators provided additionally to main steam turbogenerators driven from the main boilers. Preferably the reactor core is housed in a thick-walled concrete pressure vessel having in its wall thickness first cavities which each house a main boiler and associated steam-turbine-driven coolant circulator and second cavities which each house an auxiliary boiler, an associated auxiliary coolant circulator and a reheater, if such are provided, for steam exhausted from the steam turbines driving the main coolant circulators.
	description	1. Field of the Invention This invention provides the means and mechanism by which to produce a steady source of high-energy neutrons which, in addition to the multiplication and efficient transformation of the radioactive energy of the primary driver isotope, can also be changed in strength through simple adjustments to the physical layout of the multiplier assembly. The resulting neutron source has many practical uses including, but not limited to: startup source for a nuclear reactor, non-destructive testing of materials, neutron activation analysis, sample moisture analysis, oil well logging, medical treatment of cancer, explosive detection, metal fatigue detection, and other real-time evaluations of chemical composition and moisture content of process streams such as combustion optimization in power plants and cement kilns. 2. Description of Related Art Multiple neutron sources (emitters) are generally required in order to safely start up a nuclear reactor core. The reactor startup sources used for this purpose are referred to as “primary sources” and “secondary sources.” Primary sources are self-contained sources of neutrons that provide neutrons without the need for external power or irradiation from the reactor itself. Secondary reactor startup sources are universally made of initially non-radioactive driver materials uniformly mixed with beryllium. The secondary source driver material (typically antimony) is non-radioactive for manufacture. As a result, the secondary source does not produce a neutron source until the driver material is irradiated in a nuclear reactor. The secondary source produces neutrons as a result of the interaction of high energy gamma radiation from the radioactive decay of the driver material with the beryllium. Typical of the current art primary source driver materials, all used in combination with beryllium, are strong alpha particle emitting isotopes of polonium, radium, plutonium, americium or curium. The only material that is a practical primary source for commercial applications without the use of admixed beryllium is californium-252 or 252Cf. Descriptions of producing “secondary source” radio-isotopes within nuclear reactors is generally described by Ransohoff et al. and Bodnarescu (U.S. Pat. Nos. 3,269,915 and 3,396,077, respectively). A description of use of “primary sources” and the general use of neutron sources is described, in detail, by Impink, Jr. (U.S. Pat. No. 4,208,247—issued in June 1980, hereinafter “Impink”), where, preferably, plutonium-238 and beryllium are encapsulated in an alloy that does not allow transmission of thermal neutrons, that is, essentially “black” to thermal neutrons, such as pure cadmium; 65% silver/cadmium or 80% silver/15% indium/cadmium. A reactor start-up neutron source is used to safely assist the initiation of nuclear chain reaction in the initial core loading of nuclear reactors. A reactor startup source is required for safe startup of an initial core containing only fresh unirradiated nuclear fuel because the neutron population density from all sources (e.g., spontaneous fission of the fuel, cosmic radiation, deuterium photoneutrons) is insufficient for reliable monitoring of the reactor neutron population to assure safe reactor start-up. Low neutron fluxes occur in nuclear reactors with initial cores with only mildly radioactive fuel or after prolonged shutdown periods in which the irradiated fuel has decayed thereby reducing the inherent neutron source of the reactor from the previously mentioned mechanisms. Fixed reactor primary and secondary startup neutron sources provide a population of neutrons in the reactor core that is sufficient for the plant instrumentation to reliably measure and therefore provide reactor power and reactivity information to the reactor operator to enable a safe reactor startup and also to the reactor protection system to override the operator and halt the reactor startup if an unsafe situation is detected. Without reactor startup neutron sources, the reactor could suffer a fast power excursion during start-up before the reactor protection system could intervene to terminate the startup. The start-up sources are typically inserted in regularly spaced positions inside the reactor core either in place of some of the fuel rods or within structures inside the reactor core. In addition to the startup of nuclear reactors, neutron sources have many uses in other industrial applications. These industrial uses for neutron sources typically involve the use of the neutron source to create radioisotopes in the vicinity of the source after which the unique nuclear decay characteristics of the radioisotope(s) so created in the process being evaluated are measured and concentrations or compositions are inferred from the measurements in a process typically referred to in the art as neutron activation analysis. The resulting industrial applications include but are not limited to: non-destructive testing of materials, neutron activation analysis, sample moisture analysis, oil well logging, medical treatment of cancer, explosive detection, metal fatigue detection, and other real-time evaluations of chemical composition or moisture content in process streams such as combustion optimization in power plants and cement kilns. Impink (cited previously) further teaches that (at the time of the patent), neutron sources for commercial reactors have been positioned within the nuclear core, and remained within the core, during at least one entire operating cycle. The sources maintained a fixed position. In reactors, sources are inserted in selected fuel assemblies and extend within fuel assembly guide thimbles designed to provide structure for the fuel assembly and provide guidance for the insertion of control elements into the reactor. The sources are also disposed in assemblies close to the core periphery so as to be positioned within the detection range of the detection and monitoring apparatus outside of the reactor vessel. Beryllium is a light weight, strong but brittle, light grey alkaline earth metal. It is primarily used in non-nuclear applications as a hardening agent in alloys, notably beryllium copper. Structurally, beryllium's very low density (1.85 times that of water), high melting point (1287° C.), high temperature stability and low coefficient of thermal expansion, make it in many ways an ideal high-temperature material for aerospace and nuclear applications. Commercial use of beryllium metal presents technical challenges due to the toxicity (especially by inhalation) of beryllium-containing dusts. Beryllium produces a direct corrosive effect to tissue, and can cause a chronic life-threatening allergic disease called berylliosis in susceptible persons. In the nuclear area, beryllium is an extremely unusual element in that essentially all naturally occurring beryllium is of the 9Be isotope which has a very low binding energy (1.69 MeV) for its last neutron. The result of this peculiar aspect of the nuclear physics of beryllium is that, when excited by radiation more energetic than the threshold energy shown below, the 9Be disintegrates as shown below by neutron emission and forms the much more stable helium or carbon atoms.9Be4+4He2→12C6+1n0Eα=0 (exothermic)9Be4+γ→2·4He2+1n0Ey≧1.6 MeV9Be4+1n0→2·4He2+2·1n0En≧1.6 MeV Californium (element 98) is a rare and exclusively man-made element that is synthesized by long term irradiation of other rare man-made isotopes such as plutonium or curium in specialized high flux reactors specifically designed to produce high-order actinide isotopes. Californium (Cf) is used exclusively for applications that take advantage of its strong neutron-emitting properties. The 252Cf isotope is, by far, the most widely used isotope of californium for neutron sources due to its high source strength, production yield and relatively long half life. There are currently only two facilities in the world that currently synthesize and separate 252Cf. At this time, ˜90% of the world's annual production of ˜200 milligrams is produced at the fifty year old High Flux Isotope Reactor at the Oak Ridge National Laboratory in Tennessee. The 252Cf produced in the reactor is initially purified at the reactor site by separating the 252Cf from all of the other actinides and fission products that result from the target irradiation in a complex radiochemical process that is performed remotely in a hot cell laboratory. The separation process is concluded by coating an inert material wire, foil or other form with the 252Cf chemical compound from the separation process and placing the resulting form in a cask that shields the resulting 252Cf source material, thereby allowing the material to be removed from the hot cell laboratory. The high neutron strength of 252Cf makes it necessary for any source manufacturing subsequent to the separation of the Cf from all of the other actinides and fission products to be done remotely in a well shielded facility to protect the manufacturing staff. As a result, it is only practical to employ simple manufacturing processes in the manufacture of neutron sources using 252Cf. Even in view of previous patents cited, there seems no logical reason to try to add anything to californium as a neutron source as it is already the strongest source of neutrons by weight of any available radioisotope. Referring now to prior art FIG. 1, there is shown one embodiment of a typical thermal nuclear reactor including a sealed reactor vessel 10 housing a nuclear core 12 comprised of a plurality of fuel assemblies 14 (shown in FIG. 2A). A reactor coolant, such as one including water, enters the vessel through inlet nozzles 16, passes downward in an annular region between the vessel and a core support structure, turns and flows upward through a perforated plate 20 and through the core 12 and is discharged through outlet nozzles 22. A fuel assembly 14 is shown in prior art FIG. 2A and includes a plurality of fuel pins 24, containing nuclear fuel pellets 26, arranged in a bundle. The assembly also includes a plurality of guide thimbles 28 which provide skeletal support for the assembly and which are sized to removably receive control rods 29 of control elements 30, positionable above and within the core area by means such as electromagnets 32 which act upon shafts 34 (FIG. 1) removably connected to the control elements 30. The neutron flux within the core is continuously monitored by detection apparatus such as the neutron detectors 36 (FIG. 1) which are located at an elevation aligned with the elevation of the core 12. The detectors, located external to the vessel, may be fixed or laterally movable by positioning bars 38. The guide thimbles 28 of the fuel assemblies 14, in addition to receiving control rods 29, shown in FIG. 2A, are sized to receive neutron sources capsules shown in FIG. 2B. The capsules contain a neutron emitting source 44. The source 44 includes a major mass of fast neutron emitting material, encapsulated and held in place by cladding 48. The preferred source material, for current art reactor startup sources is 252Cf due to a combination of factors including source strength. Nonetheless, 252Cf source material is extremely expensive and only available in limited quantities, so minimizing the requirements of these materials is very important. The optimal solution for a primary source is one that minimizes the amount of 252Cf required to accomplish the required function. Additionally, the lifetime of a neutron source is determined by the minimum source strength that achieves the required function. Therefore, it is one of the main objects of this invention to make more efficient use of the 252Cf to either reduce the amount of 252Cf required for a source or to extend the useful lifetime of a given amount of 252Cf. The above problems are solved and objects met by combining a 252Cf driver source and a beryllium multiplier assembly in a manner that the large majority of the radioactive decay energy from the 252Cf driver source can be transformed into neutrons by the beryllium multiplier (“multiplier assembly”) and the resulting neutrons can then be multiplied by the beryllium (n,2n) reaction. The invention involves a fast neutron emitting source multiplier assembly, consisting essentially of a driver source of 252Cf deposited on a surface consisting essentially of foil and wire, and encapsulated and surrounded by a beryllium segment as a multiplier segment. The current art primary source designs utilize only the 3.1% of the decay events of 252Cf that are spontaneous fission events. The remainder of the decay events are high-energy alpha decays whose energy is completely shielded by the source cladding (48) that surrounds the 252Cf source (44) as shown in prior art FIG. 2B. The preferred embodiment of the invention driver source is a 252Cf coated wire or foil embedded in a recess within a simple machined beryllium multiplier. Preferably, the beryllium will be in two parts as shown in FIGS. 3A and 3B for ease of insertion of the driver source 68. The dimensions of the beryllium multiplier are only critical to the extent that the energy of the alpha particle and spontaneous fission products is captured within the beryllium multiplier. Due to the massive, charged nature of these particles, the amount of beryllium necessary to absorb the energy is much less than that necessary to form a structurally adequate container for the driver source assembly. The capture of the energy of the 252Cf alpha and spontaneous fission decay results in approximately nine-fold increase in neutron source strength per unit mass of 252Cf driver material relative to current art 252Cf primary sources. The strength of the invention neutron source can also be modulated by the inclusion of a shield curtain that can be imposed between the 252Cf driver source and the beryllium multiplier. This shield curtain is capable of stopping alpha particles and interferes with transmission of alpha particles to the beryllium multiplier. Increasing the mass of the multiplier assembly will further increase the neutron source strength by increasing the beryllium (n,2n) reaction resulting from the neutron produced directly from the 252Cf by spontaneous fission as well as those produced in the beryllium as a result of interactions with the high-energy alpha particles and fission products resulting from the 252Cf decay. The preferred embodiment encapsulates the multiplier assembly within a hermetically sealed source capsule which includes a means for holding the multiplier assembly together, preferably a spring and void volume to provide space to collect the helium gas that evolves from the beryllium disintegration reaction without over pressurizing the source capsule. In the multiplier of this invention, the neutrons produced directly by the 252Cf and those produced by the transformation of alpha and fission products by the beryllium multiplier assembly are further multiplied by beryllium (n,2n) reactions before they are emitted from the source assembly. The main innovation of this invention is the combination of 252Cf, already a strong neutron source, with the heterogeneous beryllium multiplier to complete the transformation of the 252Cf radioactive energy into neutrons. The manufacture of this invention requires that the 252Cf driver source be inserted into the multiplier assembly prior to any structural encapsulation. Further, it requires machining and fabrication of metallic beryllium or beryllium oxides. Finally, all of the manufacturing must be performed remotely in the presence of an intense neutron source. The 252Cf and Be together provide a synergy, allowing weight reduction of 252Cf from about 260 micrograms to about 30 micrograms, per multiplier assembly, an 8+x reduction due to beryllium excitation neutron multiplication. In this invention, a major amount of beryllium will be used to encase/surround/encapsulate a minor amount of 252Cf, as shown in FIG. 3A discussed below. Only 252Cf and Be are used in the multiplier assembly of this invention. The multiplier assembly consists of 252Cf coated onto wire or foil and Be. The preferred embodiment of the invention described herein utilizes all of the different types of radiation from the 252Cf so that they are efficiently transformed into neutrons. Even though the 252Cf is a very strong neutron source, neutrons are only directly produced as a result of the 3.1% of the decays that are spontaneous fission with an average of 3.77 neutrons emitted per fission. The current art 252Cf neutron sources render the remaining 96.9% of the 252Cf radioactive energy as alpha particles useless by dissipating the energy of this energy as heat in the standard source design stainless steel sheath. The preferred embodiment does not use a source sheath, which is also an extremely effective shield for the alpha particle and fission product energy, but rather utilizes a bare wire, typically of palladium, onto which 252Cf has been deposited after separation from the various irradiation products from the reactor. Instead of the wire being encapsulated in a shield, it is encapsulated in a simple beryllium multiplier assembly which then is directly illuminated with the alpha particles, fission products, prompt fission gammas and high energy neutrons that result from the decay of 252Cf. As a result, the neutron source strength of the bare 252Cf coated wire is multiplied by approximately a factor of eight to ten resulting in either a significantly stronger or longer lived source for the same amount of 252Cf or a ninefold reduction in the amount of 252Cf required for a constant source strength. Calculations have shown that the typical 600 MBq reactor startup primary source with the current art unmultiplied source requires nearly 260 μg of 252Cf while the multiplied source requires only 29 μg. Referring now to FIG. 3A, a primary source capsule 60 is shown including the driver source of 252Cf, shown as 68 coated onto a substrate wire 69, and an encasing/surrounding/encapsulating beryllium segment 64, to provide multiplier assembly 62. This multiplier assembly 62 is better illustrated in FIG. 3B. The multiplier assembly 62 can have a wide variety of uses in nuclear power plants, oil well logging and elsewhere. Here, the multiplier assembly 62 consisting of 252Cf shown as 68, coated on a substrate/surface 69, surrounded by Be, shown as 64, can be inserted or be contained/encased by a surrounding hollow tube/rod 70. The ends of the primary source capsule can be sealed by top end plug 84 and bottom end plug 84′, with a positioning element, most simply a spring 78 holding the contained/encased multiplier assembly 62 in place near or next to the bottom end plug 84′. The void volume within the primary source capsules is shown as 86, and is capable of capturing helium gas released directly by the 252Cf alpha decay as well as that generated by the beryllium decomposition reactions. While specific embodiments of the invention have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular embodiments disclosed are meant to be illustrative only and not limiting as to the scope of the invention which is to be given the full breadth of the appended claims and any and all equivalents thereof.
051924935	summary	BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is directed generally to the improvement of the overall performance of nuclear power plant control systems and nuclear reactor protection systems and more specifically to improving the performance of feedwater control systems and eliminating the interaction between the feedwater control system and the reactor protection system. 2. Description of the Prior Art In existing nuclear power plants, there are two ways to measure the water level within a steam generator. A narrow range span measures the usable water inventory within the normal range of operation while a wide range span measures the water level within the entire steam generator. This invention is directed exclusively to an apparatus and method which measures steam generator water level using the narrow range span. The narrow range span reactor protection system is comprised of two reactor trip mechanisms including a low-low water level trip and a low feedwater flow trip. FIG. 1 illustrates the logic diagrams for both of these reactor trips. The low-low water level reactor trip operates with three water level channels 10, 11 and 12. Each water level channel 10, 11 or 12 measures steam generator water level independently. Water level signals 13, 14 and 15 generated by water level channels 10, 11 and 12, respectively, and representative of the water level in the steam generator are compared to a predefined steam generator water level set point by water level comparators 16, 17 and 18. Low-low water level signals 19, 20 and 21 from water level comparators 16, 17 and 18, respectively, are input to coincidence gate 22. A low-low water level indication from any two of signals 19, 20 and 21 will cause a signal 23 to be generated which is available at an output of coincidence gate 22 to thereby initiate a reactor trip. A reactor trip is accomplished by inserting control rods into the nuclear core to take the reactor to a subcritical state. Water level signal 13 generated by water level channel 10 is also input through electrical isolation device 24 to a feedwater control system. The low feedwater flow reactor trip operates with two steam flow channels 25 and 26 and two feedwater flow channels 27 and 28. Steam flow channel 25 and feedwater flow channel 27 reside in one protection set while steam flow channel 26 and feedwater flow channel 28 are from another redundant protection set. Steam flow signal 29 and feedwater flow signal 30 generated by steam flow channel 25 and feedwater flow channel 27, respectively, are input to flow comparator 31. Steam flow signal 32 and feedwater flow signal 33 generated by steam flow channel 26 and feedwater flow channel 28, respectively, are input to flow comparator 34. A mismatch between steam flow and feedwater flow such that feedwater flow is less by a predetermined magnitude than steam flow will cause low feedwater flow signals 35 and 36 to be generated at the outputs of flow comparators 31 and 34, respectively. These low feedwater flow signals 35 and 36 are input to OR gate 37. A signal 38 will be generated at an output of OR gate 37 whenever either signal 35 or 36 indicates a low feedwater flow condition. Water level signals 14 and 15 from water level channels 11 and 12, respectively, are also input to water level comparators 39 and 40. Water level comparators 39 and 40 utilize water level set points equal to or greater than those utilized by water level comparators 16, 17 and 18. Low water level signals 41 and 42 from water level comparators 39 and 40, respectively, are input to OR gate 43. A low water level indication from either of low water level signals 41 or 42 will cause a signal 44 to be generated which is available at an output of OR gate 43. Signals 38 and 44 are input to AND gate 45. A low water level indication from signal 44 and a low feedwater flow indication from signal 38 will cause a signal 46 to be generated which is available at an output of AND gate 45 to thereby initiate a reactor trip. The Code of Federal Regulations, Title 10, Part 50.55a Codes and Standards, subpart (h) Protection Systems, endorses the Institute of Electrical and Electronics Engineers Standard IEEE-279 "Criteria for Protection Systems for Nuclear Power Generating Stations" as the governing criteria to which reactor protection system design must conform, as a minimum, in order to meet the requirements of functional adequacy and operational reliability. One of the specific provisions of standard IEEE-279 Paragraph 4.7.3 addresses the issue of control and protection system interaction and provides as follows: "Single Random Failure. Where a single random failure can cause a control system action that results in a generating station condition requiring protective action and can also prevent proper action of a protection system channel designed to protect against the condition, the remaining redundant protection channels shall be capable of providing the protective action even when degraded by a second random failure." From FIG. 1, it is evident that water level channel 10 is used both by the low-low water level reactor trip and by the feedwater control system. It is also evident that the other two water level channels 11 and 12 are used both by the low-low water level reactor trip and by the low feedwater flow reactor trip. This design conforms to the requirements established by standard IEEE-279. For example, failure in the high direction of the water level channel 10 indicating falsely that the water level within the steam generator is too high will generate feedwater control system action that results in a reduction of feedwater flow. Consequently, low steam generator water level protection may be subsequently required. This protective action is, however, derived from the remaining water level channels 11 and 12. For such a scenario, standard IEEE-279 imposes the consideration of an additional random failure in the reactor protection system. The underlying logic is that the initial protection system failure is considered the initiating event for the transient and, therefore, does not constitute the "single failure" standard IEEE-279 imposes on the protection system. As such, an additional protection system failure must be postulated to occur and the protection system must continue to be capable of initiating the appropriate protective action. The second random failure in this instance would be a failure of one of the remaining water level channels 11 or 12. Such a failure would result in only one water level channel 11 or 12 remaining in operation which is not sufficient to satisfy the two out of three reactor trip logic implemented in the low-low water level reactor trip by coincidence gate 22. Nevertheless, presuming that the initial failure occurs in water level channel 10 which is aligned to the feedwater control system and causes a control system transient, and the second random failure is in either water level channel 1; or 12, it can be seen from FIG. 1 that a reactor trip can be accomplished through the low feedwater flow reactor trip logic. A water level signal 14 or 15 from water level channel 11 or 12, respectively, remaining in operation will cause a low water level signal 41 or 42 to be input to OR gate 43 and thus cause a signal 44 to be available at the output of OR gate 43. The steam flow/feedwater flow logic will operate as previously described to produce a low feedwater flow indication at signal 38. Thus, a signal 46 will be available at the output of AND gate 45 to initiate a reactor trip. The low feedwater flow reactor trip logic is provided only to satisfy the requirements established by standard IEEE-279. This logic is not used for any other independent purpose of either reactor protection or feedwater system control. The low feedwater flow reactor trip logic introduces additional complexity into the steam generator water level protection scheme. At the same time, the use of only one water level channel 10 as an input to the feedwater control system is undesirable because failure of that single water level channel 10 causes feedwater control system transients requiring protective action. Accordingly, the need exists for a feedwater control system design that eliminates the need for the low feedwater flow reactor trip logic while at the same time improves the reliability of the feedwater control system. SUMMARY OF THE INVENTION The present invention is directed to a system for improving the performance of nuclear power plant feedwater control systems and simplifying steam generator low water level reactor protection logic. The system includes a plurality of water level channels for redundantly measuring steam generator water level and generating a plurality of signals representative thereof. The median steam generator water level signal is selected through microprocessor control from among the plurality of steam generator water level signals. The median steam generator water level signal is then communicated to the feedwater control system through an output interface. One embodiment of the present invention is directed to a system for improving the performance of nuclear power plant feedwater control systems comprised of three water level channels for redundantly measuring steam generator water level and generating signals representative thereof. A microprocessor is programmed to select a median steam generator water level signal from among the three steam generator water level signals designated as Signal A, Signal B and Signal C. The microprocessor first selects the high signal value as between Signal A and Signal B and stores this value in microprocessor memory as Signal D. The microprocessor then selects the high value as between Signal B and Signal C and stores this value in microprocessor memory as Signal E. The microprocessor next selects the high value as between Signal A and Signal C and stores this value in microprocessor memory as Signal F. The low signal value as between Signal D and Signal E is then selected and stored in microprocessor memory as Signal G. Finally, the low signal value as between Signal F and Signal G is selected and stored in microprocessor memory as the median steam generator water level signal. The median steam generator water level signal is then communicated to the feedwater control system through an output interface. The median signal selector of the present invention provides a more reliable and efficient way to control the feedwater flow within a nuclear power plant steam generator. The median signal selector prevents the failure of a single water level channel from initiating a feedwater control system transient resulting in a nuclear power plant condition requiring protective action. Therefore, the median signal selector eliminates the need for the low feedwater flow reactor trip logic as well as improves the reliability of the feedwater control system. These and other advantages and benefits of the present invention will become apparent from the description of a preferred embodiment hereinbelow.
050911422	claims	1. A method for extracting a locking sleeve (20) from a guide tube (4) in a demountable end block (5) of a fuel assembly of a nuclear reactor cooled by light water, said fuel assembly comprising a bundle of parallel fuel rods held inside a framework (9) formed by guide tubes (4), struts (3) and end blocks (5, 6) fixed onto ends of the guide tubes (4), at least one of the end blocks (5) being fixed onto one of the ends of each of the guide tubes (4) in a demountable manner, by means of an end part (4a) of the guide tube deformable radially and having a securing part (17) projecting radially outwards, engaged inside and over a part of the length of an opening (11) passing through the end block (5) and comprising, in its part receiving the guide tube (4), an annular enlargement (16) receiving the securing part (17) of the guide tube (4), radial expansion of the end of the guide tube and holding of its securing part (17) inside the annular enlargement (16) of the opening (11) of the end block being ensured by a locking sleeve (20) comprising a part for expanding the guide tube (4) and a ferrule (25) for fixing in the end block projecting at the end of the guide tube, in the locked position of the sleeve, inside a part of the opening (11) of the end block not receiving the guide tube, this part of the opening (11) of the end block comprising at least one radial cavity (22) inside which at least one deformed part (29) of the fixing ferrule (25) is introduced by radial deformation of at least one zone of the ferrule (25) coinciding with the cavity (22), so as to ensure fixing of the locking sleeve (20) inside the end block (5), said method comprising the steps of (a) deforming said at least one zone (25a, . . . 25f) of the fixing ferrule (25) comprising a radially projecting deformed part (29) by folding inwards, so as to extract the deformed part (29) from the corresponding cavity (22); and (b) extracting the locking sleeve (20) by exerting a pulling force axially of the guide tube (4). (a) deformation inwards of the at least one zone (25a, . . . 25f) of the fixing ferrules (25) comprising a radially projecting deformed part (29), so as to extract the deformed parts (29) from the corresponding cavities (22); and (b) extraction of the locking sleeves (20) by means of a pulling force axially of the guide tubes (4). 2. The method as claimed in claim 1, wherein the zones (25a to 25f) of the ferrule (25) comprising deformed parts (29) consist of cylindrical segments separated from one another by slits (26) arranged in the direction of generatrices of the ferrule (25). 3. The method as claimed in claim 2, wherein the inward folding of the cylindrical segments (25a to 25f) forming the fixing ferrule (25) is performed about a line close to a line joining the ferrule (25) and the expansion part (24) of the locking sleeve (20). 4. A method for extracting the locking sleeves (20) from all the guide tubes (4) of a demountable end block (5) of at least one fuel assembly of a nuclear reactor cooled by light water, said fuel assembly comprising a bundle of parallel fuel rods held inside a framework (9) formed by guide tubes (4), struts (3) and end blocks (5, 6) fixed onto ends of the guide tubes (4), at least one of the end blocks (5) being fixed onto one of the ends of each of the guide tubes (4) in a demountable manner, by means of an end part (4a) of the guide tube deformable radially and having a securing part (17) projecting gradially outwards, engaged inside and over a part of the length of an opening (11) passing through the end block (5) and comprising, in its part receiving the guide tube (4), an annular enlargement (16) receiving the securing part (17) of the guide tube (4), radial expansion of the end of the guide tube and holding of its securing part (17) inside the annular enlargement (16) of the opening (11) of the end block being ensured by a locking sleeve (20) comprising a part (24) for expanding the guide tube (4) and a ferrule (25) for fixing in the end block projecting at the end of the guide tube, in the locked position of the sleeve, inside a part of the opening (11) of the end block not receiving the guide tube, this part of the opening (11) of the end block comprising at least one radial cavity (22) inside which at least one deformed part (29) of the fixing ferrule (25) is introduced by means of radial deformation of at least one zone of the ferrule (25) coinciding with the cavity (22), so as to ensure fixing of the locking sleeve (20) inside the end block (5), wherein, for all the locking sleeves of all the guide tubes, the following steps are performed simultaneously:
	abstract	A self-contained source of gamma-ray and neutron radiation suitable for use as a radiation surrogate for weapons-grade plutonium is described. The source generates a radiation spectrum similar to that of weapons-grade plutonium at 5% energy resolution between 59 and 2614 keV, but contains no special nuclear material and emits little α-particle radiation. The weapons-grade plutonium radiation surrogate also emits neutrons having fluxes commensurate with the gamma-radiation intensities employed.
	claims	1. A building used for a nuclear power plant, wherein a wall portion which forms at least a part of said building is formed from a megawall structure of steel plate reinforced concrete construction that is composed by pouring concrete into megablocks composed of outer shell steel plates having a height equivalent to the plurality of floors of said building, and wherein an equipment module which is composed of steel frames formed by support columns that have a height equivalent to the plurality of said floors and function as columns inside said building and floor frames that are supported by said support columns and function as floors in said building, and various types of equipment to be installed in said building that are previously provided in said steel frames along with their ancillary piping, is provided in the building. 2. A building according to claim 1 , wherein said equipment module being self-standing in said building, and the horizontal force that acts on said equipment module is supported by a structural member of said building which surrounding said equipment module. claim 1 3. A building according to claim 2 , wherein said structural member surrounding the equipment modules is composed of said megawall structure of steel plate reinforced concrete construction that is composed by pouring and filling concrete into said megablocks composed of said outer shell steel plates. claim 2 4. A building according to claim 1 , wherein said wall portion is a wall member which forms an outer peripheral wall of said building. claim 1 5. A building used for a nuclear power plant, wherein a wall portion which forms at least a part of said building is formed from a megawall structure of steel plate reinforced concrete construction that is composed by pouring concrete into megablocks composed of outer shell steel plates having a height equivalent to the plurality of floors of said building, and wherein said building is a reactor building comprising a containment vessel and a ring-shaped pool that employs a top slab of said containment vessel for its bottom, and said pool is integrally provided with said containment vessel by extending a peripheral wall of said containment vessel upward to form a pool outer peripheral wall that has a cylindrical shape when viewed from overhead and by providing a pool inner peripheral wall on said top slab so as to be concentric with said pool outer peripheral wall. 6. A building according to claim 5 , wherein said containment vessel and pool are composed of said megawall structure of steel plate reinforced concrete construction that is composed by pouring and filling concrete into said megablocks composed of said outer shell steel plates. claim 5 7. A building according to claim 5 , wherein said containment vessel and pool outer peripheral wall are separated from a peripheral structural member and made to stand alone. claim 5 8. A building according to claim 6 , wherein said containment vessel and pool outer peripheral wall are separated from a peripheral structural member and made to stand alone. claim 6 9. A building according to claim 5 , wherein said wall portion is a wall member which forms an outer peripheral wall of said building. claim 5 10. A building according to claim 7 , wherein said structural member surrounding the equipment modules is composed of said megawall structure of steel plate reinforced concrete construction that is composed by pouring and filling concrete into said megablocks composed of said outer shell steel plates. claim 7 11. A building according to claim 8 , wherein said structural member surrounding the equipment modules is composed of said megawall structure of steel plate reinforced concrete construction that is composed by pouring and filling concrete into said megablocks composed of said outer shell steel plates. claim 8
	abstract	A composition for radiation shielding or range of compositions which compositions may be used for a variety of radiation shielding applications. With proper adhesive selection and processing, the construction forms an integral bond with the craft as compatible adhesives form strong bonds. This eliminates the potential for delaminating associated with the use of metallic layered shielding. While prior art protects electronics with a direct coating to electronic packages, this approach allows larger equipment systems, such as optics, or spectrometers, to be shielded.
	description	This application is based upon and claims the benefit of priority from prior Japanese Patent Application No. 2008-227290, filed Sep. 4, 2008, the entire contents of which are incorporated herein by reference. 1. Field of the Invention The present invention relates to an X-ray computer tomography apparatus which can helically scan an object with an X-ray cone beam. 2. Description of the Related Art In the field of X-ray CT, dynamic scanning and helical scanning, which acquire cross-sections or 3D views of the heart in the form of moving images by using X-ray cone beams, are becoming pervasive. It is an important challenge for scanning using X-ray cone beams to reduce X-ray exposure. It is an object of the present invention to reduce X-ray exposure in helical scanning using X-ray cone beams. According to an aspect of the present invention, there is provided an X-ray computer tomography apparatus comprising: an X-ray tube which generates X-rays; a two-dimensional array type X-ray detector which detects the X-rays; a rotating mechanism which rotates the X-ray tube and the X-ray detector around a rotation axis; a pair of collimators which form X-rays from the X-ray tube into a cone beam shape; a collimator moving mechanism which separately moves the pair of collimators in a direction substantially parallel to the rotation axis; a reconstruction processing unit which reconstructs image data in a reconstruction range set by an operator based on an output from the X-ray detector; and a collimator control unit which controls a position of each of the collimators, wherein the collimator control unit controls the position of each of the collimators in accordance with a distance between a central plane of the X-rays which corresponds to a cone angle of substantially 0° and an end face of the reconstruction range, and the collimator moving mechanism moves each of the pair of collimators in a range from an outermost position corresponding to a maximum cone angle corresponding to a width of the X-ray detector to an innermost position offset from a position corresponding to a cone angle of substantially 0° to an opposite side. Additional objects and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out hereinafter. An embodiment of an X-ray computer tomography apparatus according to the present invention will be described below with reference to the views of the accompanying drawing. Note that X-ray computer tomography apparatuses include a rotate/rotate-type apparatus in which an X-ray tube and an X-ray detector rotate together around an object, and a stationary/rotate-type apparatus in which many detectors are arranged in the form of a ring, and only an X-ray tube rotates around an object. The present invention can be applied to either type. Rotate/rotate-type apparatuses include a single tube apparatus in which a pair of an X-ray tube and an X-ray detector are mounted on a rotating frame, and a so-called multi-tube type apparatus in which a plurality of pairs of X-ray tubes and X-ray detectors are mounted on a rotating frame. The present invention can be applied to either type. X-ray detectors include an indirect conversion type that converts X-rays transmitted through an object into light through a phosphor such as a scintillator and converts the light into electric charges through photoelectric conversion elements such as photodiodes, and a direct conversion type that uses generation of electron-hole pairs in a semiconductor by X-rays and migration of the electron-hole pairs to an electrode, i.e., a photoconductive phenomenon. The present invention can be applied to either type. FIG. 1 shows the arrangement of an X-ray computer tomography apparatus according to this embodiment. The X-ray computer tomography apparatus according to the embodiment is compatible with cone beam helical scanning. In the following description, sides located far from and near to the center of a reconstruction range will be referred to as the outside and the inside, respectively. A gantry 100 includes an X-ray tube 101. The X-ray tube 101 receives a tube voltage and filament current from a high voltage generator through a slip ring 108, and generates X-rays. The X-ray tube 101 is mounted, together with an X-ray detector 103, on an annular rotating frame 102 which is supported to be rotatable about a rotation axis RA. The X-ray detector 103 faces the X-ray tube 101. The X-ray detector 103 detects X-rays emitted from the X-ray tube 101 and transmitted through the object. The X-ray detector 103 is a two-dimensional array type detector having a plurality of X-ray detection elements arrayed two-dimensionally and is compatible with cone beam scanning. For the sake of descriptive convenience, the rotation axis RA is defined as a Z-axis. An axis passing through an X-ray focus F and the detector center is defined as an X-axis. An axis perpendicular to the X- and Z-axes is defined as a Y-axis. The X-, Y-, and Z-axes intersect at the center of imaging. An X-ray plane perpendicular to the rotation axis RA is defined as an X-ray central plane MP. The X-ray central plane MP coincides with an X-Y plane. X-ray spread angles from the X-ray central plane MP on the positive and negative sides of the Z-axis each are defined as a cone angle. The maximum cone angle is determined by the distance between the X-ray focus F and the center of the X-ray detector 103 and the maximum width of the sensitivity region of the X-ray detector 103 concerning the Z-axis. The X-ray irradiation window of the X-ray tube 101 is provided with a pair of collimators 131 and 133 for determining a cone angle. The pair of collimators 131 and 133 which are made of lead plates and block X-rays face each other through an X-Y plane. The slit between the pair of collimators 131 and 133 is called an aperture. The pair of collimators 131 and 133 are provided to be separately moved by a collimator moving mechanism 135. The collimator moving mechanism 135 separately moves the pair of collimators 131 and 133 along the rotation axis RA (Z-axis). Each of the collimators 131 and 133 is moved in the range from the outermost position corresponding to the maximum cone angle to the innermost position offset from the position of the X-ray central plane MP corresponding to a cone angle of nearly 0° to the opposite side. Controlling separately the movement of the pair of collimators 131 and 133 can provide the aperture between the pair of collimators 131 and 133 asymmetrically with respect to the X-ray central plane MP. The X-rays emerging from the X-ray irradiation window of the X-ray tube 101 pass through the aperture between the collimators 131 and 133 to be formed into a cone beam shape. A collimator control unit 121 controls the collimator moving mechanism 135 to determine the position of each of the collimators 131 and 133. A data acquisition system (DAS) 104 amplifies an output from the X-ray detector 103 for each channel, and converts it into a digital signal. For example, this signal is then sent to a preprocessing device 106 via a noncontact data transmission device 105 to be subjected to correction processing such as sensitivity correction. A projection data storage device 112 stores the resultant data as so-called projection data at a stage immediately before reconstruction processing. In data acquisition (scanning), a scan controller 110 controls a rotation driving unit, a high voltage generator 109, the data acquisition system 104, the collimator control unit 121, and the like. An input device 115 is provided to allow the operator to input a length L and a diameter FOV of a desired reconstruction range. A reconstruction range is set in a cylindrical region having the diameter FOV and the length L centered on the rotation axis RA. A reconstruction device 114 reconstructs image data based on projection data by using a cone beam image reconstruction method. This method is typically the Feldkamp method. However, other reconstruction methods can be used. As is well known, the Feldkamp method is an approximate reconstruction method based on a fan beam convolution/back projection method. Convolution processing is performed by regarding data as fan projection data on the premise that the cone angle is relatively small. However, back projection processing is performed along an actual ray. That is, an image is reconstructed by the following procedure: assigning cone-angle-dependent weights to projection data, performing convolution for the weighted projection data by using the same reconstruction function as that for fan beam reconstruction, and back-projecting the resultant data along an actual oblique ray having a cone angle. An X-ray central plane-reconstruction range distance calculating unit 125 calculates a vertical distance (shortest distance) “d” between the X-ray central plane MP and an end face of a reconstruction range based on the position of the top on which the object is placed, detected by a top position detector 123, and the position of the reconstruction range set in the top coordinate system. A collimator position determination unit 127 separately determines the position of each of the pair of collimators 131 and 133 based on the X-ray central plane-reconstruction range distance “d” calculated by the X-ray central plane-reconstruction range distance calculating unit 125 and the diameter FOV of the reconstruction range. For example, in cone beam helical scanning, the top moves almost continuously. At this time, the X-ray central plane-reconstruction range distance “d” continuously changes. As the distance d continuously changes, the position of the collimator 131 or 133 is displaced almost continuously. If the motor of the collimator moving mechanism 135 is a stepping motor, the collimator 131 or 133 is intermittently moved. As shown in FIGS. 2 and 3, in helical scanning, continuous movement of the top and continuous rotation of the X-ray tube 101 or the like are simultaneously performed. In helical scanning, the inside collimator near the center of the reconstruction range (the collimator 133 in FIG. 3) is fixed, whereas the outside collimator (the collimator 131 in FIG. 3) continuously or intermittently moves from a position located near the inside collimator 133 beyond the X-ray central plane MP to the outermost position, passing through the X-ray central plane MP, as the top continuously moves. A scan interval is divided into a scan start interval, a scan end interval, and a scan intermediate interval. The scan start interval is the interval from the time point when the inner edge line of an X-ray cone beam coincides with the near end of the reconstruction range to the time point when the outer edge line of the X-ray cone beam coincides with the near end of the reconstruction range as the top moves. The near end of the reconstruction range is an end portion on the end face of the reconstruction range which is closest from the X-ray focus. The distant end of the reconstruction range is an end portion on the end face of the reconstruction range which is farthest from the X-ray focus. The scan end interval is the interval from the time point when the outer edge line of the X-ray cone beam coincides with the near end of the reconstruction range to the time point when the inner edge line of the X-ray cone beam coincides with the near end of the reconstruction range as the top moves. The scan intermediate interval is the interval obtained by subtracting the scan start interval and the scan end time from the scan interval. In this interval, X-rays maintain the maximum cone angle. In the scan start interval, the inside collimator 133 is fixed at the outermost position (most open position) corresponding to the maximum cone angle, and the outside collimator 131 moves from the innermost position (most closed position), which is offset from the position of the X-ray central plane MP corresponding to a cone angle of nearly 0° to the opposite side, to the outermost position (most open position). In the scan end interval, the inside collimator 131 is fixed at the outermost position (most open position) corresponding to the maximum cone angle, and the outside collimator 133 moves from the innermost position (most closed position), which is offset from the position of the X-ray central plane MP corresponding to a cone angle of nearly 0° to the opposite side, to the outermost position (most open position). Note that in the scan start interval, when the outside collimator 131 is located at the offset innermost position (most closed position), the outer edge line of the X-ray cone beam coincides with the distant end on one end face of the reconstruction range. In the scan end interval, when the outside collimator 133 is located at the offset innermost position (most closed position), the outer edge line of the X-ray cone beam coincides with the distant end on the other end face of the reconstruction range. When the top moves at a constant speed, the moving speed of the outside collimator 131 increases on the way in the scan start interval. The time point when the moving speed of the outside collimator 131 increases coincides with the time point (speed change point) when the outside collimator 131 is located at a position corresponding to a cone angle of 0°. At this time, the outside plane of the X-ray beam coincides with the X-ray central plane MP. The outside collimator 131 moves up to this speed change point such that the outside plane of the X-ray beam passes through the distant end. From the time point of the speed change point to the end of the scan start interval, the outside collimator 131 is moved such that the outside plane of the X-ray beam passes through the near end. Switching a reference for the determination of the position of the outside collimator 131 from the distant end to the near end in this manner can suppress the X-ray irradiation amount to the minimum necessary. Likewise, in the scan end interval, the moving speed of the outside collimator 133 decreases on the way. The time point when the moving speed of the outside collimator 133 decreases coincides with the time point (speed change point) when the outside collimator 133 is located at a position corresponding to a cone angle of 0°. At this time point, the outside plane of the X-ray beam coincides with the X-ray central plane MP. Up to this speed change point, the outside collimator 133 is moved such that the outside plane of the X-ray beam passes through the distant end. From the speed change point to the end of the scan start interval, the outside collimator 133 is moved such that the outside plane of the X-ray beam passes through the near end. Switching the reference for the determination of the position of the outside collimator 133 from the distant end to the near end in this manner can also suppress the X-ray irradiation amount to the minimum necessary in the scan end interval. FIGS. 4 to 8 show the movement of the collimator 131 in the scan start interval in more detail. The state in which one collimator 131 approaches the other collimator 133 across the X-ray central plane MP is called an offset state. In the offset state, the distance (offset distance) between the shield surface of the outside collimator 131 and the X-ray central plane MP is defined as “ΔOF”. The distance between the X-ray central plane MP and an end face of a reconstruction range is defined as “d”. The distance from the X-ray focus F to a Y-Z plane including the distant end of a reconstruction range is defined as “e”. FIG. 4 shows the positions of the collimators 131 and 133 at the start of data acquisition (the start of scanning). The inside collimator 133 is set at a position corresponding to a set cone angle, typically the maximum cone angle. When the front end (front edge) of an X-ray cone beam approaches the near end of a reconstruction range, data acquisition (scanning) starts. At this time, the offset distance ΔOF of the outside collimator 131 is determined to make the rear end of the X-ray cone beam pass through the distant end of the reconstruction range. The outside collimator 131 is moved to a position corresponding to the determined offset distance ΔOF. That is, the start position of the outside collimator 131 is determined such that the rear edge of the X-ray beam collimated by the outside collimator 131 (the rear end of the X-ray cone beam) passes through the distant end on an end face of the reconstruction range. The distance “e” is determined depending on the diameter FOV of the reconstruction range. The position of the outside collimator 131 is determined based on the distances “d” and “e” so as to draw a corresponding geometry. Note that in practice, a margin “α” is given to the distance “d” to prevent an X-ray irradiation error by allowing mechanical backlashes for the collimator moving mechanism 135 and the moving mechanism of the top. That is, the offset distance and position of the outside collimator 131 are determined based on the distance of (d−α). The margin “α” is set to 1/20 of the speed per second of the top, e.g., 0.5 mm. For the sake of descriptive convenience, the following description will be made on the assumption that the distance is “d”. As the top moves from the state in FIG. 4, the outside collimator 131 is moved in the same direction as that of the movement of the top, as shown in FIG. 5. This gradually decreases the offset distance ΔOF. That is, the outside collimator 131 approaches the X-ray central plane MP. The inside collimator 133 is fixed at a position corresponding to the maximum cone angle. As the distance d decreases with the movement of the top, the outside collimator 131 is moved in the same direction as the moving direction of the top so as to follow up the movement of the top while the state in which the rear edge of the X-ray beam passes through the distant end of the reconstruction range is maintained. As shown in FIG. 6, this movement is continued until the X-ray central plane MP coincides with an end face of the reconstruction range. When the top further moves from this state, the reference point is switched from the distant end of the reconstruction range to the near point of the reconstruction range, as shown in FIG. 7. The position of the outside collimator 131 is determined such that the rear end of the X-ray cone beam collimated by the outside collimator 131 passes through the near point on an end face of the reconstruction range. As the distance d increases with the movement of the top, the outside collimator 131 is further moved in the same direction as the moving direction of the top up to the maximum cone angle, as shown in FIG. 8, so as to follow up the movement of the top while the state in which the rear edge of the X-ray beam passes through the near point of the reconstruction range is maintained. In the interval in which the state in FIG. 4 changes to the state in FIG. 8, the inside collimator 133 is fixed at a position corresponding to the maximum cone angle. The reference point for the determination of a collimator position is switched from the distant end on an end face of a reconstruction range to the near point on the end face in this manner before and after the state in which the X-ray central plane MP located on the outside of the end face of the reconstruction range changes to the state in which the X-ray central plane MP is located on the inside of the end face of the reconstruction range. As a consequence, the moving speed of the collimator increases, as shown in FIG. 3. The same control as that in the scan start interval is performed in the scan end interval. In the scan end interval, as shown in FIG. 2, the outside collimator as a target to be moved is switched to the collimator on the opposite side to the target collimator in the scan start interval. That is, as the top moves, the collimator 133 gradually approaches the inside collimator 131. As described above, this embodiment can suppress X-ray exposure to the maximum by switching the reference point for the determination of a collimator position from the distant end on an end face of a reconstruction range to the near point on the end face in the above manner before and after the state in which the X-ray central plane MP located on the outside of the end face of the reconstruction range changes to the state in which the X-ray central plane MP is located on the inside of the end face of the reconstruction range. As shown in FIG. 10, in variable-speed helical scanning in which data is acquired while the speed of the top is changed, the collimator control unit 121 controls the movement of the pair of collimators 131 and 133 in a symmetrical form so as to apply X-rays to only a detector array required to reconstruct one thin slice image. The width of a portion to be irradiated with X-rays (slit width) depends on reconstruction conditions such as the number of views to be back-projected as well as scanning conditions such as the speed of the top and the number of views per rotation. That is, the collimator control unit 121 changes the slit width between the collimators 131 and 133 in accordance with the moving speed of the top, i.e., variations in helical pitch, so as to prevent fields of view for data acquisition from overlapping each other in variable-speed helical scanning. As shown in FIG. 9, in shuttle helical scanning in which data is acquired while the top is reciprocated, the above collimator control is applied to a turnabout period. As described in First Modification), the following control and operation depend on scanning conditions and reconstruction conditions: collimator control to be performed when scanning operation accompanying no bed movement shifts to scanning operation accompanying bed movement; control to minimize the slit width to obtain high image quality when scanning operation accompanies no bed movement and to separate the collimators 131 and 133 with an increase in the speed of the top; and the way to separate (increase the slit width) the collimators 131 and 133. Flying focus is to locate an X-ray focus at the same position by shifting the focus along the Z-axis in the opposite direction by the same distance per rotation in order to increase the slice resolution. In accordance with this movement amount of the focus, the collimators 131 and 133 are made to dynamically slide with the slit width being fixed. When the collimators 131 and 133 are to be moved at a speed lower than that determined by mechanical control limits, they are controlled partially linearly or nonlinearly. When the collimators are to be moved at a speed higher than that determined by the control limits, they are controlled partially linearly or nonlinearly. Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.
	description	This application is a filing under 35 U.S.C. 371 of international application number PCT/US2012/056868, filed Sep. 24, 2012, published on Apr. 4, 2013 as WO 2013/048954, which claims priority to U.S. provisional patent application No. 61/541,296 filed Sep. 30, 2011. The present invention relates to calibration and normalization systems and methods for ensuring the quality of radiopharmaceuticals during the synthesis thereof, such as radiopharmaceuticals used in Positron Emission Tomography (PET) and Single-Photon Emission Computed Tomography (SPECT). PET and SPECT imaging systems are increasingly used for detection of diseases and are useful in providing early detection and a definite diagnosis for such diseases (e.g., disease states within oncology and neurology). For example, currently, a large percentage of PET and SPECT tests are related to cancer detection and early Alzheimer detection. These diseases require early diagnosis to allow a timely and effective treatment. PET and SPECT imaging systems create images based on the distribution of positron-emitting isotopes and gamma emitting isotopes, respectively, in the tissue of a patient. The isotopes are typically administered to a patient by injection of radiopharmaceuticals including a probe molecule having a positron-emitting isotope, e.g., carbon-11, nitrogen-13, oxygen-15, or fluorine-18, or a gamma radiation emitting isotope, e.g. technetium-99. The radiopharmaceutical is readily metabolized, localized in the body or chemically binds to receptor sites within the body. Once the radiopharmaceutical localizes at the desired site (e.g., chemically binds to receptor sites), a PET or SPECT image is generated. Examples of known radiopharmaceuticals include 18F-FLT ([18F]fluorothymidine), 18F-FDDNP (2-(1-{6-[(2-[18F]fluoroethyl)(methyl)amino]2-naphthyl}ethylidene)malonitrile), 18F-FHBG (9-[4-[18F]-fluoro-3-(hydroxymethyl)butyl]guanine or [18F]-penciclovir), 18F-FESP ([18F]-fluoroethylspiperone), 18F-p-MPPF (4-(2-methoxyphenyl)-1-[2-(N-2-pyridinyl)-p-[18p]fluorobenzamido]ethylpiperazine) and 18F-FDG ([18F]-2-deoxy-2-fluoro-D-glucose). Radioactive isotopes in radiopharmaceuticals are isotopes exhibiting radioactive decay, for example, emitting positrons. Such isotopes are typically referred to as radioisotopes or radionuclides. Exemplary radioisotopes include 18F, 124I, 11C, 13N and 15O, which have half-lives of 110 minutes, 4.2 days, 20 minutes, 10 minutes, and 2 minutes, respectively. Because radioisotopes have such short half-lives, the synthesis and purification of the corresponding radiopharmaceutical must be rapid and efficient. Any quality control (QC) assessments on the radiopharmaceutical must also take place in a short period of time. Preferably, these processes (i.e., synthesis, purification, and QC assessment) should be completed in a time well under the half-life of the radioisotope in the radiopharmaceutical. Presently, QC assessments (e.g., chemical yield and chemical purity) may be relatively slow mainly due to the fact that they are conducted manually. Accordingly, there is a need for systems, components, and methods for capturing, analyzing, and interpreting data obtained during the synthesis and purification processes of a radiopharmaceutical to ensure that those synthesis and purification are proceeding efficiently to produce quality radiopharmaceuticals in a desired quantity. From this analysis, changes can be implemented before, during or after the synthesis and/or purification of the radiopharmaceutical to correct any deficiencies, as they occur during the radiopharmaceutical's synthesis. The embodiments of the present invention provide such systems, components, and methods, which allow for capture and analysis of real data, as well as the correction of deficiencies, during the synthesis of the radiopharmaceutical. A site to site comparison can also be performed to enable comparison across geographically diverse sites conducting radiopharmaceutical synthesis. An exemplary embodiment includes a method of monitoring a radiopharmaceutical synthesis process. Data relating to the radiopharmaceutical synthesis process is received from a radiopharmaceutical synthesizer. The data is analyzed. One or more characteristics of the data is identified wherein the one or more characteristics pertain to quality control factors relating to the radiopharmaceutical synthesis process. The one or more characteristics of the data are extracted. The extracted data is analyzed. Another exemplary embodiment includes a method of normalizing a radiopharmaceutical process. A first set of data relating to a first radiopharmaceutical process is received from a first radiopharmaceutical synthesizer, wherein the first set of data is based on results using a known input sample and includes data pertaining to the output of the first radiopharmaceutical process. A first correlation factor to be applied the first set of data to normalize the first set to a first baseline is calculated. A second set of data relating to a second radiopharmaceutical process is received from a second radiopharmaceutical synthesizer, wherein the second set of data is based on results using the known input sample and includes data pertaining to the output of the second radiopharmaceutical process. A second correlation factor to be applied to the second set of data to normalize the second set to a second baseline is calculated. A comparison of the first set and second set of data is performed. A third correlation factor that normalizes the first and second set of data to a third baseline based upon the comparison is calculated. These and other embodiments and advantages of the invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the principles of the various exemplary embodiments of the invention. It will be readily understood by those persons skilled in the art that the embodiments of the inventions described herein are capable of broad utility and application. Accordingly, while the invention is described herein in detail in relation to the exemplary embodiments, it is to be understood that this disclosure is illustrative and exemplary of embodiments and is made to provide an enabling disclosure of the exemplary embodiments. The disclosure is not intended to be construed to limit the embodiments of the invention or otherwise to exclude any other such embodiments, adaptations, variations, modifications and equivalent arrangements. The following descriptions are provided of different configurations and features according to exemplary embodiments of the invention. These configurations and features may relate to providing systems and methods for quality control of radiopharmaceuticals and other compounds or formulations containing radioisotopes. While certain nomenclature and types of applications or hardware are described, other names and application or hardware usage is possible and the nomenclature provided is done so by way of non-limiting examples only. Further, while particular embodiments are described, these particular embodiments are meant to be exemplary and non-limiting and it further should be appreciated that the features and functions of each embodiment may be combined in any combination as is within the capability of one of ordinary skill in the art. The figures depict various functionality and features associated with exemplary embodiments. While a single illustrative block, sub-system, device, or component is shown, these illustrative blocks, sub-systems, devices, or components may be multiplied for various applications or different application environments. In addition, the blocks, sub-systems, devices, or components may be further combined into a consolidated unit. Further, while a particular structure or type of block, sub-system, device, or component is shown, this structure is meant to be exemplary and non-limiting, as other structure may be able to be substituted to perform the functions described. Exemplary embodiments of the invention relate to synthesis systems for radiopharmaceuticals. The synthesis system may produce radiopharmaceuticals for use with either PET or SPECT scanners. For example, the synthesis system may be the FASTlab® system from GE Healthcare. The use of the FASTlab system in examples described herein is meant to be exemplary and non-limiting. It should be appreciated that the embodiments described herein may be used with a variety of synthesis systems manufactured by companies other than GE Healthcare. It should further be appreciated that the use of the term “radiopharmaceutical”, “radiotracer”, “PET tracer”, or “SPECT tracer” herein is meant to be exemplary and non-limiting and the mention of one term does not exclude substitution of the other terms in the described embodiment. During the automated synthesis of radiopharmaceutical, a data collection file for the synthesis run is generally produced. For example, for every radiopharmaceutical synthesis run on a FASTlab system, a unique log file for the run is produced. This file consists of data collected at various points in the synthesis using various sensors and activity detectors that are a part of the process, such as radioactivity detectors. The data in the data collection file may be collected at certain time intervals. For example, in a FASTlab system, a log file consists of data collected at one second intervals throughout the entire synthesis with the data being measured by up to six different radioactivity detectors, as well as set values and measured values for the programmable process parameters in the FASTlab sequence file (e.g., reactor temperature, pressure, and syringe positions). It should be understood that the data collection intervals may be adjusted and may be measured at different intervals other than every second (e.g., every five seconds or every ten seconds). Data may be collected from different sensors or radioactivity detectors at different intervals for each (e.g., every second at one detector and every five seconds at another). The data in the data collection file file, such as a log file, when presented graphically, represents a diagnostic “fingerprint” for any given FASTlab synthesis run. The fingerprint of a successful synthesis run can be established based on established data. Subsequent synthesis runs may be then compared to the fingerprint of the successful synthesis run in order to compare the performance of the synthesis system. Deficiencies or problem areas in the synthesis process can then be identified and appropriate action taken. For example, deviations from the “good” or “acceptable” fingerprint can be determined and potential problem areas in the synthesis process can be identified, such as a which step of the process is experiencing a problem or not performing up to expected standards. Using this technique, synthesizer processes across multiple sites may also be compared. As part of such comparison, it may be necessary to calculate a correlation or normalization factor, as described below, to enable the data from each run to be moved to a common baseline to ensure an accurate comparison between different synthesizers at different locations. Accordingly, the data collection file can provide valuable information about each synthesis run and may be used, for example, to monitor variations between identical runs; to see the effect of modifications to the synthesis runs; for trouble shooting; and as a tool during PET center set-up. Useful information may therefore be obtained through analysis and correlation of the data collection file data. For example, quality control information, such as, for example, yield and purity, may be extracted from the data collection file data and analyzed. Through such analysis, the radiopharmaceutical synthesis process may be adjusted based on this quality control information. This analysis process may simplify quality control procedures through the potential elimination of post-production quality control tests since the results can be determined from the synthesis process itself. In addition to the information from sensors and activity detectors, such as the radioactivity detectors, the data collection file may contain set values and real, or measured, values for the programmable process parameters in the synthesizer's sequence file. For example, a FASTlab log file contains measurements of data from the following programmable process parameters: reactor heater temperature, nitrogen pressure, vacuum, and syringe position. Accordingly, the use of information from the activity detectors in combination with process parameters in the data collection file adds valuable information regarding given steps and actions in the process. According to other exemplary embodiments, using activity detector readings obtained from data collection files, the synthesizer reaction performance may be monitored. However, radioactivity detector measurements need to be corrected and correlated in order to account for variation in readings amongst different synthesizers located at different locations or sites. In order to perform such a correction, a calibration or normalization process is used to standardize the process data to enable comparison on an equivalent baseline. According to an exemplary embodiment, a basic sequence for the synthesizer is used where a sample with a known amount of radioactivity is passed through the synthesizer in the vicinity of the different radioactivity detectors. A correlation factor for each detector is then calculated based on the results compared to the known radioactivity amount and used during the data analysis to monitor the synthesizer process performance. Once instruments at different locations are calibrated or normalized, the resulting data can be collected and further normalized to account for variations at the different locations. In doing so, data collected from the different locations can be meaningfully compared. This collected data can be centrally analyzed and stored in order to provide various support functions to the different locations such as troubleshooting and customer service. During the above process, the sample is passed throughout the synthesizer hardware and the activity is read at each radioactivity detector. During the process, when comparing two sites, say, sites A and B, each having a synthesizer, the data collection file may show that all detectors in A read as expected, but one detector, for example, detector 5 at B reads 10% below what is expected. If it is known that the detector is functioning properly and is aligned properly, then the presumption is that there is a systematic error associated with that detector that causes it to read low. The data is collected from sites A and B at a central data collection site. The central collection site would use the data to normalize the data from the detectors at site B upwards by 10% so that the data for the same detector at site A can be compared to the data from site B. Once calibrated, sites A and B proceed with synthesis. Each synthesizer typically generates a data collection file during production of a radiopharmaceutical. The contents of the data collection file are transmitted to the same central data collection site either in real time or at some point after the synthesis run is complete. Provided the same radiopharmaceutical is being synthesized at each site, the data generated from sites A and B could be compared. The data for site B, of course, would have to be normalized up to account for the fact that its detector 5, is known to read low. The data may show production trends or issues with each site. For example, the data collection file data could show that there was a good solid phase extraction (SPE) recovery, but a low reported yield in the synthesizer at site A. These data may then form the basis for troubleshooting the synthesizer at site A. Upon analysis of the data, a conclusion may be drawn with regard to the problem at site A. For example, the conclusion could be that there was a low yield for the a radiolabelling step or some other synthesizer step. The data collection file data may serve a number of uses. Exemplary, non-limiting uses may include: Process development, including tuning of purification processes in a synthesizer, including the SPE process(es); Robustness testing: a robust process would show little deviation from run to run since the graphical representation of the data for each of the radioactivity detectors are like “fingerprints” of the process; Troubleshooting: problems can be spotted and pinpointed in the radiosynthesis from the trends of the radioactivity detectors deviating from a successful production based on established data; Support PET center set-up; Ensuring production quantity matches the patient need (e.g., ensuring that the proper number of patient doses is produced); Identification of trends of the radioactivity detectors at various sites to determine performance of different synthesizers; Identification of synthesizer hardware problems; Identification of synthesizer sequence file programming issue(s); Simplified post-synthesis quality control; Providing remote customer support; and Normalization of data collection files, e.g., log files. FIG. 1 depicts a flow chart of a method of synthesizing and using a PET or SPECT imaging agent and extracting data collection file data according to an exemplary embodiment of the invention. The method 100 as shown in FIG. 1, may be executed or otherwise performed by one or a combination of various systems, components, and sub-systems, including a computer implemented system. Each block shown in FIG. 1 represents one or more processes, methods, and/or subroutines carried out in the exemplary method 100. At block 102, a radioisotope is produced. The radioisotope (e.g., 18F or 11C) is typically produced using a cyclotron (e.g., GE PETtrace 700 cyclotron) for PET radioisotopes or using a generator for SPECT radioisotopes (e.g., to produce the 99Tc). The cyclotron or generator may be located at a manufacturing site or it may be located in proximity to the scanner. Locating the cyclotron or generator on-site with the PET or SPECT scanner minimizes transportation time for the radioisotope. It should be appreciated that while “PET” and “SPECT” are referred to herein such examples are exemplary and the mention of one does not preclude application to the other. At block 104, a radiopharmaceutical is synthesized using the radioisotope. A synthesizer is used to combine the radioisotope with a radioligand. The result is a radiopharmaceutical. The synthesizer may be manually operated, semi-automated in operation, or fully automated. For example, the GE Healthcare FASTlab system is a fully automated synthesizer. The synthesizer is generally operated in a “hot cell” to shield the operator from the radioactivity of the radioisotope. During the synthesis of the radiopharmaceutical, data can be collected during the process. The data corresponds to radiodetector or sensor measurements at various points in the synthesis process. The data are collected at various time intervals and may be electronically stored. The data may be output or saved in the form a data collection file. The synthesizer may employ a cassette which is mated thereto and contains the various reagents and other equipment, such as syringe pumps and vials, required for the synthesis of the radiopharmaceutical. The cassette may be removable and disposable. Cassettes may be configured to support the synthesis of one or more radiopharmaceuticals. At block 106, the synthesized radiopharmaceutical is dispensed. The doses of the radiopharmaceutical are dispensed into collecting vials for patient administration and for QC. A sample of the bulk synthesized radiopharmaceutical may be dispensed directly into a QC system and/or cassette for QC testing. Systems and methods of QC testing are shown in PCT Appl. No. US11/2011/048564 filed on Aug. 22, 2011, the contents of which are incorporated herein by reference in their entirety. At block 108, quality control checks on a radiopharmaceutical sample are performed. There may be one or more QC checks performed. These QC checks may be automated. The QC system may include a cassette having a plurality of components for performing the tests. The cassette may be configured for insertion into a QC system to carry out the QC checks. The QC system may be a stand-alone system or it may be integrated with the synthesizer described above. Radiopharmaceutical doses are dispensed from the synthesizer. Sample(s) from one or more dispensed vials may be selected for QC checks. These samples may be input to the QC system. Alternatively, the QC system may be connected or coupled to the synthesizer such that an appropriate sample may be directly output from the synthesizer to the QC system. At block 110, a dose from the same production batch as the sample on which the QC tests were conducted is administered to a patient. At block 112, a PET or SPECT scan is performed on the patient who received the dose. At block 114, a data collection file is produced from the synthesizer. This file, which contains data collected during the radiopharmaceutical synthesis, is produced. The data collection file may be formatted and contain data as described herein. Alternatively, other formats for the file may be used. For example, the file may be a log file such as produced by the GE Healthcare FASTlab system as described above. The use of the term “data collection file” or “log file” herein is mean to be exemplary and non-limiting, as there are other terms that may be used for such a data collection file with data collected during a radiopharmaceutical process. It should be appreciated that the data collection file may be produced at any point during the synthesis process. The data collection file may be produced in hard copy format and/or may be stored electronically. For example, the data collection file may be printed by an output device communicatively coupled to the synthesizer, such as a printer. Alternatively, the data collection file may be output or stored in an electronic format. For example, the synthesizer may have an electronic display or be coupled to a computer system for displaying the data collection file in an electronic format. The data collection file may be electronically saved using electronic storage, either internal to the synthesizer or external thereto. For example, the synthesizer may have solid state storage, both temporary, such as random access memory and/or more permanent such as flash memory or hard disk type storage. It should also be appreciated that the synthesizer may have input devices to allow for user interaction with the system. These input devices may be communicatively coupled to the system. For example, the synthesizer may have a QWERTY type keyboard, an alpha-numeric pad, and/or a pointing input device. Combinations of input devices are possible. The synthesizer may be communicatively coupled to a computer network. For example, the synthesizer may be communicatively coupled to a local area network or similar network. Through such a network connection, the synthesizer may be communicatively coupled to one or more external computers, computer systems, and/or servers. In some embodiments, the synthesizer may be communicatively coupled to the Internet. The synthesizer may be wirelessly connected to the computer network or may be connected by a wired interface. The synthesizer may transmit and receive data over the computer network. For example, the data collection file may be transmitted over the computer network to another computer system or server. This other computer system or server may be remotely located at a geographically separate location from the synthesizer. Furthermore, the synthesizer may be computer implemented such that synthesizer includes one or more computer processors, power sources, computer memory, and software. As stated above, the synthesizer may be communicatively coupled to one or more external computing systems. For example, the synthesizer may be communicatively coupled through a computer network, either wired or wireless or a combination of both, to an external computer system. The external computer system may provide commands to cause the synthesizer to operate as well as collect and analyze data from the data collection file. This combination of computer hardware and software may enable to the synthesizer to automatically operate and to perform certain collection of data, analysis of the data, and implementation of corrections or factors derived from the data. At block 116, the data collection is analyzed. In accordance with exemplary embodiments, the data collection file is analyzed as described herein. As part of the analysis, certain factors and information may be gleaned from the data collection file. Using these factors and information, the radiopharmaceutical process may be altered, modified, and/or tuned. For example, the data analysis may determine that the process is not operating efficiently because a low yield is indicated. By way of non-limiting example, this may be indicative of a problem in the reaction vessel. A fix or modification may be implemented. Such a fix or modification may be manually applied by an operator or may be implemented automatically by the synthesizer based on command issued through a computer system. In some embodiments, the system may be completely automatic and no outside intervention is needed to perform an analysis and implement a correction or modification to the process. FIGS. 2A and 2B depict a data collection file according to an exemplary embodiment. For example, FIGS. 2A and 2B may depict a log file from a FASTlab system. FIG. 2A depicts a first portion 200A of the data collection file and FIG. 2B depicts a second portion 200B of the data collection file. The first and second portions are parts of the data collection file; that is, FIGS. 2A and 2B may be put together side by side to form an exemplary data collection file. Alternatively, the data collection file may be apportioned as depicted, such as being split into multiple sections. It should be appreciated that the data collection file may be divided into different sections than shown. This data collection file may represent the data collection file containing data produced as shown in the method 100, for example. The data collection file has a header row 202 with labels on each of the data columns therebelow, as shown in FIGS. 2A and 2B. Exemplary column labels in the header row 202 are depicted in FIGS. 2A and 2B. It should be appreciated that additional or less column labels may be contained in the data collection file. Furthermore, the data and the formatting of the data depicted in each of the columns is meant to be exemplary and non-limiting. These data are meant to depict data collected during an exemplary radiopharmaceutical synthesis process for FACBC, which is used as a non-limiting example. As shown in FIG. 2A, the data points are shown at one second intervals. Each of the data columns (labeled by header row 202) represents a point or state in the radiopharmaceutical process. Data collected from different radioactivity detectors is shown (labeled as “Activity Detector No. N,” where “N” is the detector number). These radioactivity detectors measure radioactivity in their vicinity. It should be appreciated that the Activity Detectors described herein are positioned in exemplary positioned. More or less Activity Detectors may be used and the positioning of the Activity Detectors may be customizable with respect to the synthesizer and the cassette. FIG. 3 depicts a plot of data collection file data according to an exemplary embodiment. The plot 300 represents a plot of data collection file data, such as the data depicted in the exemplary data collection file of FIGS. 2A and 2B. The plot 300 has a legend 302. As can be seen, the plot 300 is a plot of the Activity Detector data for Activity Detectors Nos. 1, 2, 4, and 5. The plot 300 may plot Activity Measured 304 versus Elapsed Time 306. A detailed explanation of a data collection file plot is provided in FIG. 4 below. The details are equally application to other data collection file plots, such as the plot 300. FIG. 4 depicts a plot 400 with an overlay of the components of the radiopharmaceutical synthesis process. As shown by the legend 402, the plot 400 is a plot of the activity at three different detectors. The plot 400 represents the same data as plotted in the plot 300 described above. The plots 300 and 400 depict the activity during the radiopharmaceutical synthesis process. Specifically, by way of non-limiting example, the plots 300 and 400 depict a data collection file obtained during the synthesis of Fluciclatide. An exemplary radiopharmaceutical synthesis process is superimposed on the plot 400 as shown in FIG. 4. It should be appreciated that although this exemplary process is described in terms of production of Fluciclatide using 18F, the basics of the process and the components may be used in the production of other radiopharmaceuticals with appropriate modifications as understood in the art. The process begins with the purification of [18F] obtained through, e.g., the nuclear reaction 18O(p,n)18F by irradiation of a 95% 18-enriched water target with a 16.5 MeV proton beam in a cyclotron. The radioactivity is collected on a QMA cartridge 404 where 18F is trapped; impurities are removed; and the 18F is subsequently eluted at path 406 into a reaction vessel 408. In the reaction vessel 408, the 18F is first conditioned through a drying step to remove solvents including residual water, thus making the 18F more reactive. Next, at 408a, also in the reaction vessel 408, the 4-trimethylammonium benzaldehyde is labeled using the 18F, thereby replacing the 4-trimethylammonium moiety with a 18F. The resulting 4-[18F]benzaldehyde (FBA) is transferred at path 410 to an MCX cartridge 412 for purification of FBA as shown at 412a. The FBA is transferred at path 414 back to the reaction vessel 408 and is conjugated at 408b with a Fluciclatide precursor AH111695 to form Fluciclatide as shown at 408c. This reaction is shown in detail in Scheme I, below. Next, using path 416, the Fluciclatide is transferred to and passed through the first of two SPE cartridges 418. The Fluciclatide obtained from the first SPE cartridge 418 subsequently migrates to a second SPE cartridge 420 for further purification (the SPE cartridges 418 and 420 may also be referred to as tC2 SPE cartridges). The Fluciclatide is transferred at 422 to a syringe 424 through which it is transferred at 426 into a production collection vial (PCV) 428. Although two SPE cartridges are shown in FIG. 4, the synthesizer may have one or more than two SPE cartridges and the SPE cartridges may be of different types and configurations. According to exemplary embodiments, Activity Detector No. 1 is positioned in the vicinity of the QMA cartridge, Activity Detector No. 2 is positioned in the vicinity of the Reactor Vessel, and Activity Detector No. 5 is positioned in the vicinity of the outlet of the process that leads to a syringe or a production collection vial. The elution of 18F off the QMA cartridge and into the reactor is illustrated by the sudden drop of the Activity Detector No. 1 trace and the rapid increase of the Activity Detector No. 2 trace at section 450 of the plot. The “jump” in the Activity Detector No. 2 trace after approximately 1000 sec (at section 452 of the plot) is caused by increased volume in the reactor when precursor is transferred into the reactor after evaporation of solvent. This jump occurs because activity is moved closer to the detector as the volume rises inside the reactor. The only difference in height is caused by the decay of 18F. During the labeling process, the volume remains constant and the slope of this plateau (at section 454 of the plot) illustrates the decay of the fluoride [18F-]. The activity detector is sensitive enough to even detect “splatter” inside the reactor when precursor is added. The purification of the FBA by the MCX cartridge is illustrated by the drop in the Activity Detector No. 2 trace followed by a lower plateau during the period the FBA is trapped inside the MCX cartridge, at section 456 of the plot. In other words, there is no detector located in proximity to the MCX cartridge. The trace increases again when activity is transferred back to the reactor. It should be appreciated that the elapsed time depicted refers to the start of the sequence, not the start of the overall synthesis. After starting a sequence, a synthesizer can be left idle for a period of time at a given step waiting for eventual delayed fluoride. A dialog box on the synthesizer may be need to be checked before proceeding. The start of sequence time is when this box is checked. After the second synthetic step the Activity Detector No. 2 trace drops when product was transferred out to two SPE cartridges for final purification as shown in section 458 of the plot. When product is eluted off the SPE cartridge, and transferred to the production collection vial, it passes by Activity Detector No. 5. FIG. 5 depicts a plot showing how certain information, specifically yield information, can be gleaned from the data collection file data according to an exemplary embodiment. Plot 500 depicts a plot similar to that of FIG. 4. The overall yield 502 is the sum of the first yield step 504 and the second yield step 506. These yield values can be used to assess the performance of the overall process, as well as identify problem areas of the process. According to exemplary embodiments, an exemplary or “standard” process with an exemplary yield may be determined for the system. The resulting data collected during the exemplary process, e.g., the measurements of the Activity Detectors, is plotted. The yield can be determined as shown in FIG. 5. This resulting plot may form an exemplary “fingerprint” for the system. Subsequent runs made using the system can then be compared to this exemplary process. Deviations from the fingerprint can be noted through plots of the data collection file data as described above. From analysis of the plots in this comparison, problems with the system and its process may be readily identified and subsequently corrected. According to exemplary embodiments, if the trace shown in FIG. 3 is taken to be the fingerprint of a process that is optimal, a subsequent trace (e.g., from a subsequent synthesis run or from an instrument at a different site) can be compared to it. If the fingerprint of the subsequent trace varies significantly (e.g., more than 2%; more than 5%; more than 10% or more than 15%) in any region (e.g., the region that is covered by detectors 1, 2, 3, 4 or 5), the operator (or the synthesizer automatically) can diagnose the step of the synthesis that is not proceeding properly. According to exemplary embodiments, variations in the first yield step 504 and the second yield step 506 can be used to identify where in the process a problem may be occurring, either at the labeling step that forms [18F]FBA; the conjugation step that forms [18F]fluciclatide; or with any purification step involved in the synthesis process. FIG. 6 depicts a set of yield predictions according to an exemplary embodiment. A table 600 represents data and yield predictions. The data is exemplary and non-limiting. According to exemplary embodiments, data is gathered from several synthesis runs on the same machine, as shown in column 602. Alternatively, or concurrently, these data can also be gathered from several locations or sites. These sites may be geographically separated and each site operates a radiopharmaceutical process on its synthesizer. The predicted yields, in this case from several runs on the same machine, are in column 604. The reported yields are in column 606. The predicted yields are calculated based upon the yields obtained from a plot, such as the plot 500. It can be recognized that the yield data gleaned from the data collection file data agrees with the reported yield for the radiopharmaceutical. The reported yield is determined by a comparison of the first and second yields to the overall yield as shown in FIG. 5 above. The difference between these quantities is the percentage yield. It should be appreciated that the process can have several steps and actions and this is an exemplary comparison, as additional steps and actions may need to be taken into account for determining the overall yield. It is advantageous to be able to glean overall yield data from the data collection file of the synthesizer because such a determination may mean one less QC assessment that has to be performed on the sample, post-production prior to administering any of the produced radiopharmaceutical to a patient, thus saving time and resources. In addition to yield data one can also glean purity data from the data collection file. One of the detectors not shown in FIGS. 4 and 5 is Activity Detector No. 4. This detector is located in the vicinity of the two SPE cartridges, as SPE cartridges 418 and 420 depicted in FIG. 4. While, the data from this detector is not shown in FIGS. 4 and 5, it is nevertheless collected during the synthesis run. When this data is plotted the traces shown in FIGS. 7A and 7B may be obtained. It should be understood that these traces are exemplary only. FIGS. 7A and 7B depict traces 700 and 702 of activity from Activity Detector No. 4 for a portion of the synthesis reaction. Both figures contain plots of multiple traces from different runs. For example, FIG. 7A depicts traces from multiple runs at a particular site as indicated by the legend 702. FIG. 7B shows three different traces obtained while the SPE cartridges were kept at three different temperatures, as shown by the legend 704. From these traces, it can be observed that the changes in activity measured from the highest, or maximum, activity read by Activity Detector No. 4 and the minimum activity read by the detector can be correlated to the level of impurities present in the radiopharmaceutical produced in any given synthesis run (referring to the right hand portion of the traces, shown by section 706 of the traces). For example, in FIG. 7A, the smaller the change in activity between the maximum value of any given trace, such as section 710, and the minimum value for any given trace, such as section 712, is correlated to high levels of impurities. In contrast, the larger the change in activity between the maximum value of any given trace, such as section 714, and the minimum value for any given trace, such as section 716, is correlated with lower levels of impurities. FIG. 7B also depicts this behavior, in this case of the synthesis of the radiopharmaceutical anti-1-amino-3-[18F]fluorocyclobutane-1-carboxylic acid, otherwise known as FACBC. The trace 720, which depicts activity at 27° C., has total impurities of 106 μg/mL. The trace 722, which depicts activity at 30° C., has total impurities of 56 μg/mL, while the trace 724, which depicts activity at 28° C., has total impurities of 79 μg/mL. The trace behavior depicts these impurity levels. From FIG. 7B, it can be seen that the distance from the point 730 of the trace 720 to its lowest value 732, it much less than either of the similar points of the traces 722 and 724 (such as, for example, the distance from the point 734 on the trace 722 and the lowest value 736 is greater than that of trace 720. A similar analysis may be performed for the trace 724 (with the highest point and lowest point being labeled as 738 and 740, respectively). A specific portion of the trace at a specific time may be designated for the measurement of the high and low points to ensure consistency among readings for different traces. From the data collection file one can also glean data regarding how effective certain processes are during the synthesis run. FIG. 8 depicts a plot 800 of a series of traces depicting a portion of runs shown activity at Activity Detector No. 5 during the final SPE purification step at a particular site. The plot 800 is exemplary and non-limiting. A legend 802 is provided. A table 804 provides a summary of the run number vs. SPE recovery % vs. reported yield percentage. The behavior of the traces shown in the plot 800 can be analyzed and conclusions drawn therefrom. For example, focusing on the trace and data corresponding to run J181 (labeled by 806 in the legend 802 and the table 804), certain behavior can be seen. For example, the large delta between the SPE Recovery % and the Reported Yield % is usually indicative of a problem in the synthesis process, specifically the labeling step (e.g., the step yielding [18F]FBA, when the radiopharmaceutical in question is [18F]fluciclatide). In the case of run J181, in the synthesis of [18F]fluciclatide, such a large delta is indicative of a problem in the labeling step yielding [18F]FBA. It should be appreciated that in practice every step and action are monitored and abnormal indications can be detected. For example, untypical syringe movement can be detected through the data collection files. The activity detectors are capable of catching the consequence or result of a particular step or action during the synthesis process. Hence, it can be see if the action, e.g., an atypical syringe movement, affected the outcome the production. Data corresponding to this run can be seen in FIG. 6 at 610 also. The data 610 shows that the run has a low fluorination in the step of 45% (depicted in the Yield Labeling column of table 600). Based on this, the trace 808 corresponding to this run in FIG. 8 behaves in a certain manner. For example, the trace 808 has a higher activity than the other runs in the latter part of FIG. 800. By noting behavior of this sort, insightful observations can be made into a particular synthesis process and what is happening at each step. This and other observations can be made from an analysis of the data and the traces therefrom. FIGS. 9A-C each depict an activity plots or traces from three different production sites based on data collection file data. By way of non-limiting example, FIG. 9A represent a production run at a site in Norway, FIG. 9B represents a production run at a site in Sweden, and FIG. 9C represents a production run at a site in the UK. Each run is a Fluciclatide production run using a synthesizer, which by way of non-limiting example are FASTlab systems here. As can be seen in each Figure, data corresponding to Activity Detectors Nos. 1, 2, 4, and 5 are plotted for each. Legends 902, 904, and 906 on each FIG. 9A-C, respectively, provide reference to the traces for each Activity Detector. As can be seen, each plot is similar in structure and shape to that shown in FIGS. 3 and 4 described above, as these plots were obtained using the same equipment and process as depicted in those Figures. When comparing FIGS. 9A-C, it can be seen that there are differences in the relative peak heights; e.g., between the readings of Activity Detector No. 1 (QMA) and Activity Detector No. 2 (reactor) between the different production sites and their specific synthesizers. In an ideal case, the readings of Activity Detectors Nos. 1 and 2 should be almost equal since the amount of activity entering reactor after elution of the QMA is supposed to be almost the same since the recovery activity from the QMA is >99%. The same variations are also seen between Activity Detectors Nos. 2 and 5. The differences between Activity Detectors Nos. 2 and 5 are used for the overall yield predictions (as described above). Hence, inaccuracy of these two detectors effects the accuracy of yield prediction. In data given in FIG. 6 (which represents data corresponding to FIG. 9A), correlation between estimated and reported yields is observed. However, when the same estimations are done on other synthesizers, e.g., FIGS. 9B and 9C, the effect of variations between Activity Detectors Nos. 2 and 5 are seen. FIG. 10 includes this data. FIG. 10 depicts a data table corresponding to the plots of FIGS. 9A-C. The data 1002 labeled as “NMS” corresponds to FIG. 9A; the data 1004 labeled as “UI” corresponds to FIG. 9B; and the data 1006 labeled as “TGC” corresponds to FIG. 9C. The differences in yield data may be attributed to the differences in the Activity Detector measurements. As seen in FIG. 10, the accuracy of the yield prediction varies between sites and particular synthesizers. In order to use the data for analysis of the synthesizer production for troubleshooting or other investigations, the data from the data collection files, e.g., log files, (as described above) are extracted from the synthesizer and analyzed. Plots, such as those in FIGS. 9A-C are created. However, since there are variations amongst synthesizers, even at the same site, the data analysis may be not be directly comparable. Activity trending may be a useful tool for monitoring reaction performance. A method of correcting activity detector measurements is described. A basic synthesizer sequence where a known amount of activity is passed in vicinity of the different Activity Detectors. This is accomplished by mating a cassette with the synthesizer (as would be done if a production run was being made. The cassette may be specifically configured cassette to support the required measurements or a production cassette may be used, possibly with modifications. No chemical reactions are required. The operations required are trapping and elution of the QMA cartridge with an accurately known volume followed by movement of the eluted 18F-fluoride solution around the cassette using syringe movements and gas pressure. A correlation factor for each detector can then be calculated as shown in the following example. When activity arrives from the cyclotron, the activity is accurately measured in an ion chamber. For illustration purposes, the net activity transferred on to the synthesizer in this example is 100 GBq. In the synthesizer, Activity Detector No. 1 reads 80 GBq, Activity Detector No. 2 reads 110 GBq, and Activity Detector No. 5 reads 90 GBq. The readings are then adjusted for decay. For simplification of the present example, the decay correction is not included. Based on the readings, the correlation factors for this particular synthesizer would then be: Correlation factor for Activity Detector No. 1: 100/80=1.25 Correlation factor for Activity Detector No. 2: 100/110=0.91 Correlation factor for Activity Detector No. 5: 100/90=1.11 Data for the other detectors including any custom placed additional detectors can of course be obtained in the same manner and correlation factors can be calculated. The correlation factors can then be used during the data analysis of the data collection file. This methodology does not require a modification to the synthesizer system's programming. It should be appreciated that calculation could be a part of a PET center set-up since the detector check is straightforward. This operation could be repeated on regular basis to see if detectors need to be calibrated. This operation can be repeated with different activities for control of the radio detector linearity. This operation can be carried out across multiple sites and, by using the correlation factors, activity detector readings can be compared across these multiple sites. It should further be appreciated that additional correlation factors can be calculated to compare data from synthesizers to other baselines or standards. While the foregoing description includes details and specific examples, it is to be understood that these have been included for purposes of explanation only, and are not to be interpreted as limitations of the present invention. While the embodiments have been particularly shown and described above, it will be appreciated that variations and modifications may be effected by a person of ordinary skill in the art without departing from the scope of the invention. Furthermore, one of ordinary skill in the art will recognize that such processes and systems do not need to be restricted to the specific embodiments described herein. Other embodiments, combinations of the present embodiments, and uses and advantages of the present invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. The specification and examples should be considered exemplary.
	description	FIG. 1 is a profile cross-section of a related art liquid metal nuclear reactor, such as that described in co-owned U.S. Pat. No. 5,406,602 to Hunsbedt et al. issued Apr. 11, 1995, incorporated herein in its entirety by reference. As seen in FIG. 1, annular or circular concrete silo 8, potentially underground, houses annular containment vessel 2 that in turn houses reactor 1, potentially all concentrically aligned. Reactor 1 includes a nuclear reactor core 12 submerged in a liquid metal coolant, such as liquid sodium. A space, shown as gap 3, between reactor 1 and containment vessel 2 may be filled with an inert gas, such as argon. Reactor 1 and containment vessel 2 are suspended vertically downward from upper frame 16. Concrete silo 8 may support upper frame 16 by seismic isolators 18 to maintain structural integrity of containment vessel 2 and reactor 1 during earthquakes and allow uncoupled movement between those structures and surrounding silo 8. Reactor 1 is controlled by neutron-absorbing control rods 15 selectively inserted into or withdrawn from reactor core 12. Reactor 1 may be shut down entirely for responding to an emergency condition or performing routine maintenance by inserting control rods 15 into core 12 of fissionable fuel to deprive the fuel of the needed fission-producing neutrons. However, residual decay heat continues to be generated from core 12 decreasing exponentially over time. This heat must be dissipated from shut-down reactor 1. The heat capacity of the liquid metal coolant and adjacent reactor structures aid in dissipating the residual heat. For instance, heat may be transferred by thermal radiation from reactor 1 to containment vessel 2. Heat from containment vessel 2 may also radiate outwardly toward concrete silo 8 spaced outwardly therefrom. Systems for removal of this decay heat vent or otherwise remove the heat from reactor 1 and surround structures to a heat sink such as the environment. One such system may be a reactor vessel auxiliary cooling system (RVACS) as shown in FIG. 1. Heat collector cylinder 5 may be concentrically between containment vessel 2 and silo 8 and define hot air riser 4 between containment vessel 2 and an inner surface of heat collector cylinder 5. Heat collector cylinder 5 may further define cold air downcomer 7 between silo 8 and an outer surface of heat collector cylinder 5. Heat may be transferred from containment vessel 2 to air in hot air riser 4. The inner surface of heat collector cylinder 5 may receive thermal radiation from containment vessel 2, with the heat therefrom being transferred by natural convection into the rising air for upward flow to remove the heat via air outlets 9. Heating of the air in riser 4 by the two surrounding hot surfaces induces natural air draft in the system with atmospheric air entering through air inlets 6 above ground level. The air from inlets 6 is ducted to cold air downcomer 7, then to the bottom of concrete silo 8, where it turns and enters hot air riser 4. The hot air is ducted to air outlets 9 above ground level. FIG. 2 is a schematic cross-section of heat collector cylinder 5 in a vertical direction, orthogonal to the view of FIG. 1, between reactor silo 8 and containment vessel 2. An outer surface of heat collector cylinder 5 may be covered with thermal insulation 5a to reduce transfer of heat from heat collector cylinder 5 into silo 8 and into the air flowing downward in cold air downcomer 7. The greater the differential in temperature between the relatively cold air in downcomer 7 and the relatively hot air within riser 4, drives natural circulation for passive air cooling, without motor-driven pumps. This natural circulation will occur during normal reactor operation and during shutdown, with the sodium within reactor vessel 1 is at its normal level 10 (FIG. 1). Similar, related passive reactor coolant systems are described in U.S. Pat. No. 5,190,720 to Hunsbedt et al., issued Mar. 2, 1993, and U.S. Pat. No. 8,873,697 to Horie et al., issued Oct. 28, 2014, all of which are incorporated herein by reference in their entireties. Example embodiments include damper systems for use in nuclear reactor passive cooling systems, including related RVACS for molten salt reactors and other cooling channels. Example systems include a damper that is moveable in a coolant conduit between fully open, closed, and intermediate positions to restrict coolant flow to a desired degree. For example, the damper may mostly block the flow conduit during steady state operations, limiting coolant flow to 10% or less and retaining heat in the reactor for thermodynamic efficiency. The damper nonetheless moves, without external or powered intervention, into an open position at failure or in a transient scenario involving loss of power and/or reactor overheat to permit maximum cooling. Movement of the damper may be achieved by a joint or hinge securing the damper in the flowpath, with an attachment holding or moving an end of the damper to desired positions and degrees of openness. Opening the damper may be achieved in several ways in example systems, many by passive means. For example, an electromagnet may hold the damper to the attachment in a closed position when receiving electricity, and then the damper falls or is passively biased into the open position when power is lost in a transient scenario. Or for example, a winch or other movement device may hold the attachment in the closed position, and then the damper reverts to the open position as the winch loses power in the transient. Or for example, a power source and switch(es) may be configured to provide power to the damper and/or any attachment or actuator for the same, and the switches may open in a transient scenario, allowing the damper to move into its default open position. The switch may be temperature-dependent and exposed to the coolant or reactor system so as to detect overheat and/or otherwise open, such as by melting, at a threshold temperature where cooling is necessary. Example embodiments may be installed in coolant flowpaths at any time, potentially even during plant operation, to reduce or substantially eliminate passive coolant flow, and thus heat loss, during steady-state operation. A damper and/or temperature dependent switch may be installed directly in the coolant flow, while other components like a power source, winch, manual switches, etc. may be external or positioned anywhere desired. As the damper is moved to a position blocking a desired amount of coolant flow, heat-loss, flow-induced vibration, and extreme temperature gradients in the cooling system and reactor may be reduced for improved operations, while the damper will reliably and fully permit complete coolant flow during non-steady-state accidents and other scenarios requiring the coolant flow. Because this is a patent document, general, broad rules of construction should be applied when reading it. Everything described and shown in this document is an example of subject matter falling within the scope of the claims, appended below. Any specific structural and functional details disclosed herein are merely for purposes of describing how to make and use examples. Several different embodiments and methods not specifically disclosed herein may fall within the claim scope; as such, the claims may be embodied in many alternate forms and should not be construed as limited to only examples set forth herein. It will be understood that, although the ordinal terms “first,” “second,” etc. may be used herein to describe various elements, these elements should not be limited to any order by these terms. These terms are used only to distinguish one element from another; where there are “second” or higher ordinals, there merely must be that many number of elements, without necessarily any difference or other relationship. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of example embodiments or methods. As used herein, the term “and/or” includes all combinations of one or more of the associated listed items. The use of “etc.” is defined as “et cetera” and indicates the inclusion of all other elements belonging to the same group of the preceding items, in any “and/or” combination(s). It will be understood that when an element is referred to as being “connected,” “coupled,” “mated,” “attached,” “fixed,” etc. to another element, it can be directly connected to the other element, or intervening elements may be present. In contrast, when an element is referred to as being “directly connected,” “directly coupled,” etc. to another element, there are no intervening elements present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). Similarly, a term such as “communicatively connected” includes all variations of information exchange and routing between two electronic devices, including intermediary devices, networks, etc., connected wirelessly or not. As used herein, the singular forms “a,” “an,” and the are intended to include both the singular and plural forms, unless the language explicitly indicates otherwise. Indefinite articles like “a” and “an” introduce or refer to any modified term, both previously-introduced and not, while definite articles like “the” refer to the same previously-introduced term. It will be further understood that the terms “comprises,” “comprising,” “includes,” and/or “including,” when used herein, specify the presence of stated features, characteristics, steps, operations, elements, and/or components, but do not themselves preclude the presence or addition of one or more other features, characteristics, steps, operations, elements, components, and/or groups thereof. The structures and operations discussed below may occur out of the order described and/or noted in the figures. For example, two operations and/or figures shown in succession may in fact be executed concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved. Similarly, individual operations within example methods described below may be executed repetitively, individually or sequentially, so as to provide looping or other series of operations aside from single operations described below. It should be presumed that any embodiment or method having features and functionality described below, in any workable combination, falls within the scope of example embodiments. The Inventors have recognized that related passive coolant systems such as RVACS are always open to the environment and passively removing heat around a nuclear reactor. Indeed, as described in co-owned US Patent Publication 2017/0025194 to Loewen et. al, incorporated herein by reference in its entirety, always-cooling passive systems may actually accelerate airflow and cooling. While constant heat removal is useful in accidents, during normal power operations the Inventors have recognized that RVACS and related passive coolant systems can represent a significant loss of power, and thus economic efficiency, of a reactor. For example, potentially up to 2 MWth can be lost in conventional liquid metal reactor designs through always-on RVACS passive cooling. Always-on passive cooling in a high-temperature reactor may also cause steep temperature gradients across reactor, containment, and cooling structures, resulting in material deformation, corrosion, and/or fatigue. The constant air flow in an RVACS or other passive system may further induce unwanted vibration, potentially at irregular or resonance frequencies, that can damage or wear related systems. Passive cooling, however, must be retained for plant safety. To overcome these newly-recognized problems as well as others, the inventors have developed example embodiments and methods described below to address these and other problems recognized by the inventors with unique solutions enabled by example embodiments. The present invention is fluid flow control systems and methods of using the same in nuclear reactor coolant systems. In contrast to the present invention, the few example embodiments and example methods discussed below illustrate just a subset of the variety of different configurations that can be used as and/or in connection with the present invention. FIG. 3 is a schematic illustration of an example embodiment coolant control system 100 useable in a nuclear reactor passive fluid heat exchanger flowpath 50, such as in RVACS of FIGS. 1 & 2. For example, system 100 may be installed in a horizontal piping connecting hot air riser 4 to exhaust 9 in an RVACS. Or, for example, system 100 may be installed in any other coolant fluid flowpath for flow control in the same. As shown in FIG. 3, example embodiment system 100 includes a moveable damper 101 that limits flow in fluid flowpath 50. Damper 101 is shown in solid line in a closed or partially-closed position, and in dashed line where moveable to an open position in FIG. 3. Damper 101 may be a plate, disc, or sheet of metal, plastic, or other fluid-blocking or limiting material that substantially seats to edges of flowpath 50, such as in a flow conduit in RVACS. Damper 101 may further be porous or include holes, cut-outs, and/or other flow passages that allow some reduced amount of flow through damper 101, potentially to prevent pressure building or stagnation of fluid. Damper 101 is moveable between open and closed positions. For example, damper 101 may be substantially rigid and attached to a pivot 107 and attachment 102 to rotate between open and close positions, and increments thereof, in flowpath 50. As seen in FIG. 3, damper 101 may be in a first, closed position shown in solid line and released or moved to a second, open position shown in dotted line. When so moved, additional airflow through an RVACS, or other coolant fluid through flowpath 50, may be permitted, potentially up to full natural-circulation-induced RVACS flow for emergency cooling. When in a closed position, however, damper 101 may significantly limit flow through flowpath 50, so as to limit natural or forced circulation and in turn heat removal from a reactor by a fluid in flowpath 50. For example, if used in an RVACS system, closed damper 101 may prevent significant coolant flow from or in a hot air riser 4 to exhaust 9 (or into cold air downcomer 7 from air inlets 6) and thus prevent cooling and loss of heat from the reactor when closed. Such substantially reduced flows may still permit small amounts, such as 10% or less, of maximum coolant flow, to prevent stagnation and keep system 100 at a relatively same temperature as coolant throughout a system. Damper 101 may be moved to several desired degrees of open and closed positions in several ways. For example, attachment 102 may release damper 101 to rotate about hinge 107 from the closed position shown in solid to the open position shown in dashed lines. Damper 101 may drop by a passive force, such as gravity, a spring, under force of fluid flow in flowpath 50, etc., to the open position when released from attachment 102. For example, attachment 102 may be or include an electromagnet that holds damper 101 in the closed position through a magnetic field interacting with magnetic material in damper 101. Attachment 102 may also be a mechanical fastener such as a hook and eyelet, chain interlink, screw and threaded hole, etc. or a direct connection. As power to an electromagnet in attachment 102 is cut off, or as attachment 102 is moved or rotated into a detaching configuration, damper 101 may detach from attachment 102 and move to the open position automatically through gravity or a spring in hinge 107, for example. Similarly, while not passive, a motor or other biasing drive may move damper 101 into the open position as desired. Or, for example, damper 101 may be moved through movement of attachment 102. Attachment 102 may be connected to a winch 106 or actuating transducer or other moving structure, potentially outside flow conduit 50, that moves the same to desired positions in flowpath 50. Damper 101 may move with attachment 102 to achieve desired levels of closing flowpath 50. Similarly, attachment 102 may be repositioned to re-connect with damper 101 after a separation. For instance, following de-energizing of an electromagnet in attachment 102, damper 101 may assume its open position far from attachment 102; the electromagnet may be reenergized and positioned (shown in dash), such as via winch 106, sufficiently close to damper 101 to magnetically rejoin with attachment 102 and be repositioned into a closed position in flowpath 50. As seen in FIG. 3, as damper 101 is held closed, flow through conduit 50 is restricted, and any cooling caused by such air is limited. If used in an RVACS, such as that of FIGS. 1 and 2, heat transfer from reactor 1 and containment 2 may be limited, reducing heat loss, temperature gradient, and flow-induced vibration, and improving thermodynamic efficiency. Damper 101 may still be opened through movement and/or release by attachment 102, preserving passive airflow through systems like RVACS. As shown in FIG. 3, damper 101 may be moved passively and/or moved to a fail-safe open condition in example embodiment system 100. Power source 104 may provide electrical power to a circuit for such fail-safe opening. For example, power source 104 may be a DC generator, battery, power provided by plant grid, etc. that is always on when a nuclear reactor plant is in a steady-state operating condition. Power source 104 via the circuit may power winch 106 and/or attachment 102, such as by holding winch 106, attachment 102, and damper 101 in a most restricted position or powering an electromagnet in attachment 102. When power source 104 is deactivated or its circuit is opened, winch 106 and/or attachment 102 may lose power and allow damper 101 to return to an open position under the force of gravity, from a spring bias, under force of airflow, etc. Similarly, when power is regained, winch 106 may be extended for attachment 102 to rejoin to damper 101 and then retracted to move damper 101 into a closed position. In this way, damper 101 may always open in a loss of power scenario, maximizing flow, and potentially cooling, through flowpath 50. One or more switches, such as temperature-dependent switch 103 and/or manual switch 105, may also be provided on the circuit to cut power to winch 106 and/or attachment 102 to open damper 101. For example, manual switch 105 may be an operator controlled switch from a control room or a local circuit breaker that the plant operator can activate to cause damper 101 to enter its maximum opening position when not powered by power source 104. Similarly, temperature-dependent switch 103 may open upon ambient conditions reaching a threshold temperature, such as a temperature associated with abnormal operating conditions or an urgent need for cooling. For example, switch 103 may use a meltable conductor that opens the circuit at elevated temperatures. Depending on placement of switch 103 in proximity to a heat source, such as a reactor or hot exhaust, an amount and properly-alloyed material, such as Wood's metal, will melt and break/open the circuit at a specific temperature. Or, for example, a bimetallic spring or other temperature-dependent material may physically move out of contact with the circuit so as to break it at the threshold temperature. Because other aspects of example embodiment system 100 may be passive, an operator may not be required to take any action—temperature dependent switch 103 will cause damper 101 to move to a maximally-open position when a temperature associated with a transient or necessary cooling is reached. Although temperature-dependent switch 103 is shown in a same flowpath 50 as damper 101, it is understood that switch 103 may be remote and/or at a specific location that allows accurate temperature measurement and/or reflects cooling needs. As seen above, several different structures are useable alone or in combination to passively open a damper in a coolant flowpath when such coolant is required. No external motor, battery, power source, human intervention, moving part, etc. is required to open damper 101 at a critical temperature or other transient condition. Structures are useable together to provide redundant fail-safes, such as temperature-dependent switch 103 that causes damper 101 to move to an open position at a reactor overheat temperature used in combination with a powered circuit that also causes damper 101 to move to the open position at loss of power 104 and/or human intervention via switch 105. Active systems, however, are useable in connection with example embodiment system 100, including fine movements of damper 101 with a winch 106 or other positioning device to achieve a desired incremental closure of flowpath 50, an active switch 105 that requires physical movement by an operator, etc. Example embodiment system 100 may be fabricated of resilient materials that are compatible with a nuclear reactor environment without substantially changing in physical properties, such as becoming substantially radioactive, melting, embrittlement, and/or retaining/adsorbing radioactive particulates. For example, several known structural materials, including austenitic stainless steels 304 or 316, XM-19, zirconium alloys, nickel alloys, Alloy 600, etc. may be chosen for any element of components of example embodiment debris filters. Joining structures and directly-touching elements may be chosen of different and compatible materials to prevent fouling. Example embodiment coolant control system 100 can be installed at plant fabrication or at any point at plant life. For example, system 100 may be installed in an existing RVACS or added to the same during plant construction by installing damper 101, temperature-dependent switch 103, and attachment 102 in flowpath 50, with associated power source 104 and winch 106 outside the same or elsewhere. This installation may even be performed while coolant is flowing through flowpath 50. Once installed, example embodiment system 100 may be held in a closed position with damper 101 reducing coolant flow with no further action required by an operator, or damper 101 may be actively moved to desired positions, such as by winch 106, under operator control. System 100 will nonetheless (re-)open flowpath 50 upon loss of power source 104 and/or reaching a transient temperature threshold that opens switch 103, without operator intervention. Example embodiments and methods thus being described, it will be appreciated by one skilled in the art that example embodiments may be varied and substituted through routine experimentation while still falling within the scope of the following claims. For example, although a coolant flowpath in an RVACS is shown, other reactor coolant conduits can be used simply through proper shaping and sizing of example embodiments—and fall within the scope of the claims. Such variations are not to be regarded as departure from the scope of these claims.
	description	This application is a National Phase filing under 35 U.S.C. §371 of PCT/FR2007/002155 filed Dec. 21, 2007, which claims priority to Patent Application No. 0611383, filed in France on Dec. 26, 2006. The entire contents of each of the above-applications are incorporated herein by reference. The invention relates in general to processes for estimating the concentration of a chemical element in the primary coolant of a nuclear reactor, in particular boron. More specifically the invention relates to a process for estimating the concentration C of a chemical element in the primary coolant of a nuclear reactor, this reactor comprising means for injecting a dilution solution having a concentration of the said chemical element which is below a predetermined limit into the primary coolant, means for injecting a concentrated solution of the said chemical element in a predetermined concentration C* into the primary coolant, and a sensor capable of measuring a quantity Cm representing the concentration C of the said chemical element in the primary coolant. In nuclear reactors in which the primary coolant is essentially water, as for example in pressurised water reactors, the reactivity of the reactor core is controlled among other things by adding boron to the primary coolant. Boron is a neutron poison, which absorbs some of the neutron flux generated by the nuclear reactions in the reactor core. Thus when the boron concentration of the primary coolant increases, the heat released by the core of the reactor decreases. Conversely, when the boron concentration in the primary coolant decreases, the heat released by the reactor core increases. The boron concentration in the primary coolant is adjusted automatically or manually in relation to set reactor control levels, for example in relation to the setting for the electrical power which the reactor has to provide to the high voltage electricity distribution grid. With this object the reactor is provided with a circuit known as the REA. This circuit comprises means for injecting a solution comprising essentially water and not containing boron into the primary coolant with a view to downwardly adjusting the boron concentration in the primary coolant. The REA circuit also comprises means for injecting a concentrated solution containing 7000 ppm of boron into the primary coolant in order to adjust the boron concentration in the primary coolant upwards. In both cases the volume of primary coolant is maintained constant by removing from the primary circuit a volume of liquid corresponding to the volume injected. It is thus very important for control of the nuclear reactor to know the boron concentration in the primary coolant at all times. With this object the reactor is provided with one or more sensors (boron meters) designed to measure the boron concentration in the primary coolant. The boron concentration of the primary coolant measured automatically by the boron meter is inaccurate (noise of the order of 7%) and is provided after a significant delay, of the order of some twenty minutes. In order to overcome the measurement delay, the boron concentration in the primary coolant can be estimated by integrating the flows of water and concentrated solution injected into the primary coolant via the REA. These flows underlie changes in the boron concentration. The flow integration method is based on the following equations. The change dC in the boron concentration C of the primary coolant for a constant mass of primary coolant M is caused by injecting a charge of liquid having a boron concentration C(concentrated boron or water solution) and by simultaneously removing a charge of primary coolant having concentration C. The mass balance is therefore written as:MdC=Cdm−Cdm where dm is the mass of both the charge of liquid injected and the charge of primary coolant withdrawn, where C=0 ppm for a dilution and C=7000 ppm for the injection of a concentrated boron solution. If it is assumed that the injected and withdrawn flows are constant and the same, the balance becomes:MdC=(C−C)qdt where q is the injected/withdrawn flow and dt is a time interval. By integrating we obtain: ln ⁡ ( C ⁡ ( t ) - C ) = ln ⁡ ( C ⁡ ( 0 ) - C * ) - q M ⁢ t where C(0) is the boron concentration in the primary coolant at t=0,that is C ⁡ ( t ) = C * + ( C ⁡ ( 0 ) - C * ) ⁢ ⅇ - q M ⁢ t or also ( C * - C ⁡ ( t ) ) = ( C * - C ⁡ ( 0 ) ) ⁢ ⅇ - q Vol ⁢ t if q is no longer a mass flow but a volume flow, Vol being the volume of primary coolant. This process has the advantage that it allows the change in boron concentration after the end of the action of dilution or injection of concentrated boron solution (boron addition) to be quickly estimated. The fact that the delays associated with the time required for the charge to flow through the primary circuit and the time required for the injected charge to become diluted and for the boron concentration to become uniform in the primary coolant are not taken into account brings forward estimation of the boron concentration by some ten minutes. The above equations can be used to simulate different types of action (dilution or boron addition) for a constant injection flow, and also to simulate a stationary situation (no injection). They provide the final concentration (after the action) on the basis of an initial concentration (before the action). It is therefore necessary to update the starting concentration C(0) before each action, and this enables an iterative approach to be used. In this iterative approach, the following equation is applied to each time step k: ( C * - C k + 1 ) = ( C * - C k ) ⁢ ⅇ - q Vol ⁢ Δ ⁢ ⁢ t where Ck is the estimated boron concentration in the primary coolant in step k, C* being chosen to be 0 or 7000 ppm, as before, depending on whether the action in progress is dilution or boron addition. Δt is the duration of a time step. The first disadvantage of the process of integrating flows is that there is long term drift in the estimated value in relation to the actual value (see for example FIG. 2). This drift arises from cumulated errors in each time step, due for example to the difference between the flow q used by the equations and the actual injected flow. The second disadvantage arises from the initialisation stage, which is required for an iterative process of this kind. Initialisation must be as accurate as possible, otherwise the results will be skewed at each time step. It can be done by selecting a mean of the measurements made by the boron meter over a given time as an initial value C0 for the boron concentration in the primary coolant. In the case of FIGS. 2 and 4 to 6 the iterative process (line 2) has been initialised using the mean of the values found during the four hours preceding the start of the process. In this case it is however impossible to be sure that the mean obtained represents the actual boron concentration at the moment when the iterative process started. Initialisation may also be carried out by using the boron concentration measured by chemical determination as the initial value, which is accurate, but tedious and not very fast. In any event, the cumulative effect of these two disadvantages results in this method being not very robust. Furthermore, the process using the integration of flows ignores other sources of variation in boron concentration, such as for example the injection of fluid into the primary circuit from the pressuriser, the RCV tank, the demineralisation filters, etc. In this context the intention of the invention is to provide a process of estimation which is more robust than the process of integrating flows. With this object, the invention relates to an estimation process of the aforesaid type, characterised in that the process is an iterative process comprising repeatedly at each time step k: a stage of acquisition of a quantity (qdk) representing the injected flow of the dilution solution in step k, a quantity (qck) representing the injected flow of concentrated solution in step k, and a quantity (Cmk) representing the concentration of the said chemical element measured by the sensor in the primary coolant; a stage of calculating an estimated value (Cek+1) for the concentration of the said chemical element in the primary coolant in step k+1 based on the representative quantities (qdk, qck, Cmk) acquired in step k. The process may also have one or more of the following characteristics, considered individually or in all technically possible combinations: the calculation stage is carried out using Kalman equations; the stage of calculation in step k is carried out considering a state parameter x=ln(C) in the Kalman equations when the quantity (qck) representing the injected flow of concentrated solution is below a predetermined limit, and a state parameter x=ln(C−C) when the quantity (qck) representing the injected flow of the concentrated solution is above the said predetermined limit; the stage of calculation in step k is carried out by considering a measured parameter y=ln(Cm) in the Kalman equations when the quantity qck representing the injected flow of concentrated solution is below a predetermined limit, and a state parameter y=ln(C−Cm) when the quantity qck representing the injected flow of concentrated solution is above the said predetermined limit; the equations used in the calculation stage are:xk+1/k=xk/k+uk uk=−(Δtk/Vol)qdk when the quantity (qck) representing the injected flow of the concentrated solution in step k is below a predetermined limit uk=−(Δtk/Vol)qck when the quantity (qck) representing the injected flow of a concentrated solution in step k is above a predetermined limitPk+1/k=Pk/k+W xk+1/k+1=Xk+1/k+Kk+1(yk+1−Xk+1/k)Pk+1/k+1=(1−Kk+1)Pk+1/k Kk+1=Pk+1/k/(Pk+1/k+V)where xk/k is the value of state parameter x in step k determined on the basis of data available in step k, Δtk is the duration of time step k, Vol is the volume of the primary circuit, Pk/k is the variance of state parameter x in step k determined from data available in step k, and W and V are predetermined constants; the ratio V/W lies between 100 and 10000; the process comprises an initialisation stage during which an estimated initial value Ce0 of the concentration of the said chemical element in the primary coolant is calculated directly from the quantity Cm0 representing the concentration of the said chemical element measured by the sensor in the primary coolant; the chemical element is boron or a boron compound, and the nuclear reactor is a pressurised water nuclear reactor. The process shown diagrammatically in FIG. 1 is intended to estimate the boron concentration C in the primary coolant of a nuclear reactor. This reactor, as described above, comprises means for injecting a dilution solution having a concentration of the said chemical element which is below a predetermined limit into the primary coolant, means for injecting a concentrated solution of the said chemical element having a predetermined concentration C* into the coolant, and a sensor capable of measuring a quantity Cm representing the concentration of the said chemical element in the primary coolant. The injection means comprise the reactors REA circuit, which is capable of injecting water not containing boron (dilution solution), or a concentrated solution, for example at a concentration C* of 7000 ppm of boron. The REA circuit is known and will not be described here. The process is an iterative process comprising: an initialisation stage; then, repeatedly, at each time step k: a stage of acquisition of a quantity qdk representing the injected flow of the dilution solution in step k, a quantity qck representative of the injected flow of concentrated solution in step k, and a quantity Cmk representing the concentration of the said chemical element measured by the sensor in the primary coolant; a stage of calculating an estimated value Cek+1 for the concentration of the said chemical element in the primary coolant in step k+1 based on the representative quantities qdk, qck, Cmk acquired in step k. In the course of the initialisation stage an initial estimated value Ce0 is selected for the boron concentration of the primary coolant. This value is calculated directly from the quantity Cm0 representing the concentration of the said chemical element measured by the sensor at the moment when the iterative process is initiated or immediately prior thereto. This value is calculated using a single measurement made by the sensor, and is not the mean of several measurements made by the sensor at several instants. The calculation of Ce0 does not involve measurement of the quantities representing the injected flows of dilution solution or concentrated solution. The acquisition stage is performed using one or more flow sensors in the REA circuit, and using the boron meter. The calculation stage is carried out with the help of Kalman equations. Kalman filtering is a known modelling process and only a few theoretical elements will be mentioned below. The application of Kalman filtering to estimation of the boron concentration of the primary coolant will be detailed below. The Kalman filter is designed to model the state of a process characterised by a state vector x. It is based on the following two equations. Equation for change in the state vector:xk+1=Axk+Buk+wk Observation equation:yk=Dxk+vk. The equation for change in the state vector corresponds to modelling of the process, u being a control and w being noise (modelling noise and/or control noise). The state vector x for the process is the quantity for which an attempt at estimation is made. It may have one or more dimensions, each coordinate of the vector corresponding to a characteristic parameter in the process. The measurement vector y is a function of the state x and the measurement noise v. y has the same dimension as x. A, B and D are square matrices, having the same dimension as x. The Kalman filter makes it possible to weight the information obtained from the previous controls in advance against measurements made during operation and available at a particular time. This weighting is optimal if noises v and w, which are assumed to be independent, having a mean of zero and known covariance, are Gaussian. They can be used to minimise the mathematical expectation of the error between the state and its estimate. The Kalman filter equations for the discrete state are as follows. In the text below xk\|k represents the best estimate of xk obtained from the data available in step k, that is to say before measurement yk+1 is available. Likewise, xk+1/k and yk+1\|k represent the best estimates of xk+1 and yk+1 which can be obtained from the data available in step k, that is to say before measurement yk+1 is available. The equation of state gives:xk+1\|k=Axk\|k+Buk. The estimation error is given by:xk+1−xk+1\|k=A[xk−xk\|k]+wk. The covariance matrix for the estimation error xk+1−xk+1\|k is represented by Pk+1\|k. As the noise w from the covariance matrix W is independent of the estimate, we obtain:Pk+1\|k=APk\|kAT+W The predicted measurement yk+1\|k and the covariance matrix for the associated error Qk+1/k can likewise be deduced from the observation equation:yk+1\|k=Dxk+1\|k Qk+1\|k=DPk+1\|kDT+V, where V is the covariance matrix for noise v. Once measurement yk+1 is known, we obtainxk+1\|k+1=xk+1\|k+Kk+1(yk+1−yk+1\|k), i.e.:xk+1\|k+1=xk+1\|k+Kk+1(yk+1−Dxk+1\|k)where Kk+1=Pk+1\|k DT(DPk+1\|kDT+V)−1 and the expression for the covariance matrix for the estimation error is deduced from this:Pk+1\|k+1=Pk+1\|k−Kk+1DPk+1\|k, i.e.:Pk+1\|k+1=(I−Kk+1D)Pk+1\|k where I is the identity matrix. To sum up, the Kalman equations are as follows: Prediction equations:xk+1\|k=Axk\|k+Buk Pk+1\|k=APk\|kAT+W Filtering equations:Kk+1=Pk+1\|kDT(DPk+1\|kDT+V)−1 xk+1\|k+1=xk+1\|k+Kk+1(yk+1−Dxk+1\|k)Pk+1\|k+1=(I−Kk+1D)Pk+1\|k Application of these equations to estimation of the boron concentration in primary coolant will now be described. The state parameter and the measured parameter considered for application of the Kalman equations differ according to whether the charge injected into the primary circuit is a charge of water or a charge of concentrated boron solution, or again if nothing is injected, as indicated in the table below. In practice a distinction is made between two cases, switching between the two forms of the state parameter and between the two forms of the measured parameter taking place according to the flow of concentrated solution. State parameter xMeasured parameter yFlow of concentratedx = ln(C(t))y = ln(Cm)solution zeroFlow of concentratedx = ln(C* − C(t))y = ln(C* − Cm)solution not zero The measured parameter is obtained directly from the boron concentration measured by the boron meter, y=ln(Cm) (dilution) or y=ln(C−Cm) (boron addition). The value C considered in the formulae for the state and measured parameters (if the flow of concentrated solution is not zero) corresponds to the boron concentration of the concentrated solution. The Kalman equations adapted for estimation of the boron concentration are scalar and become: Prediction equations:xk+1\|k=xk\|k+uk with uk=−(Δtk/Vol)qk, where Δtk is the duration of time step k, which is considered to be constant, and qk is the injection flow at instant k, qk being taken to be equal to qdk when the flow of concentrated solution is zero, and being taken to be equal to qck when the flow of concentrated solution is not zero.Pk+1\|k=Pk\|k+W where P is the variance of the state parameter x, and W is the variance of the noise w. Filtering equations:xk+1\|k+1=xk+1\|k+Kk+1(yk+1−xk+1\|k)Pk+1\|k+1=(1−Kk+1)Pk+1\|k with Kk+1=Pk+1\|k/(Pk+1\|k+V), where V is the variance of noise v. As FIG. 1 shows, for each step k the calculation stage comprises a sub-stage of appropriately rewriting the state and measured parameters, followed by a calculation sub-stage. In the course of the rewriting sub-stage the form of the state and measured parameters is first selected according to the representative value of the flow of concentrated solution obtained at the acquisition stage. Then, still within the rewriting sub-stage, initial values of the state and measured parameters which have to be considered for the calculation sub-stage are estimated from the final values obtained in step k−1. If the form of the state and measured parameters is the same in step k and step k−1, the initial values of the state and measured parameters which have to be considered in step k are the same as the final values obtained in step k−1. Conversely, if the forms of the state and measured parameters differ between step k and step k−1, the final values of the state and measured parameters obtained in step k−1 have to undergo a conversion in order to obtain the initial values which have to be considered for step k. The two sub-stages of the calculation stage are carried out using the same microprocessor. Comparative performance of the process of estimation using Kalman filtering and the other processes mentioned above (direct measurement and flow integration) have been evaluated for three burn-ups of cycle 13 at the Cattenom 1 nuclear power station in France, over periods of one month, so as to estimate any drift—November 2003 for the start of the cycle (FIG. 4), January 2004 for the middle of the cycle (FIG. 5) and December 2004 for the end of the cycle (FIG. 6). The comparative performance for the short-term reproduction of the actions of boron addition or dilution have been evaluated for a particular day under load, the 30 Nov. 2003, again for the Cattenom 1 nuclear power station (FIG. 2). As FIGS. 2 and 4 to 6 illustrate, combined use of the control information (start of injection) and boron concentration measurements makes it possible to cumulate the advantages of the flow integration method and the process by directly using the values read by the boron meters. Appropriate adjustment of the V/W ratio can be used to adjust the respective weights for control and measurement. The V/W ratio is generally chosen to be between 100 and 10000, preferably between 1000 and 5000, and even more preferably around 2000. An increase in the V/W ratio emphasises control over measurement. It can therefore be used to follow injections of water or concentrated boron solution more faithfully, but may yield estimates which are further from the measured value. Conversely, a smaller V/W ratio emphasises measurement over control. It provides estimates which are closer to measurements, but follows the injection of water or concentrated boron solution with a longer delay. As in the case of the flow integration process, the boron concentration estimated by Kalman filtering quickly follows changes in boron concentration due to actions of boron addition or dilution. It will be seen in FIGS. 2 and 4 to 6 that when the boron concentration changes as a result of the injection of water or boron, the Kalman filter closely follows the flow integration method in the short term. It is here that the benefit of reducing the delay in comparison with measured boron concentration lies. In the longer term the Kalman filter follows the measured values, subject to the injections of water or concentrated boron solution being well spaced out. There is therefore no long-term drift as in the flow integration method (see for example the last few days in FIG. 5) because the Kalman filter resets itself in relation to the measured value. The problem of delay in measurement of the actual boron concentration is also eliminated, because measurements are only really taken into account when there is no rapid change in the boron concentration due to control (injections from the REA). Unlike the integration process, this method makes it possible to see changes in boron concentration which are not directly due to the injection of charges from the REA, because the measurements are taken into account, but with however the delay inherent in measurement if the changes are fast. Furthermore, there is absolutely no need to introduce an accurate initial boron concentration at the initialisation stage. The Kalman filter reconstitutes the boron concentration on the basis of the measured value in a few moments, starting from any initial value. However, the more accurate the initial value the more quickly the estimated boron concentration will reach the value that it would have had with accurate initialisation. By way of example, with an initial difference of 100 ppm the difference is less than 1 ppm after 25 minutes. FIG. 3 illustrates the behaviour of the Kalman filter with an aberrant initialisation of 500 ppm (line 3′) instead of approximately 1075 ppm (line 3 corresponding to initialisation using the measured boron concentration). Lines 3 and 3′ converge quickly and overlap less than three hours after initialisation. The fact of taking the first boron concentration value measured by the boron meter (as in the case of line 3) is a practical method of initialisation which yields a small initial difference from the true concentration (of the order of 25 ppm at most) and very rapid convergence. In addition to this, the process using the Kalman filter brings about a significant reduction in noise in comparison with measurement alone (reduction by a factor of 10 over 24 hour stability in November 2003 in FIG. 4). In order to improve the accuracy of short-term modelling, the delays (of the order of ten minutes or so) due to the time required for homogenisation of the charge injected into the primary coolant and the time for the injected charge to flow through the primary circuit can be taken into account. The flow time may be reflected by a time offset of a few minutes (pure delay) in the injected flows. Likewise the introduction of a time constant (first order filtering of flows) can be used to simulate the effects of homogenisation of the charge injected into the primary circuit. These improvements are only useful for increasing the accuracy of the estimated boron concentration on the scale of a few minutes after injection. It is also possible to take the dead volume in the REA injection pipe at the end of each injection into account. In fact, the charges of water and concentrated boron solution pass through the same injection pipe. Furthermore, the charges are never wholly injected, a small dead volume remaining in the injection pipe when injection is complete. This volume is of the order of a hundred liters or so. Each new charge injected <<pushes out>> the remaining dead volume of the preceding charge into the primary pipe. The dead volume effect therefore appears when the REA successively injects two charges of a different nature, water then concentrated boron solution or vice versa. This effect can be taken into account in modelling by considering that when a charge of a different nature from the previous one is injected, injection of the previous charge continues as long as a volume equivalent to the dead volume has not been injected. Without making this addition to the simulation, the estimated boron concentration may temporarily differ from the true concentration by 3 to 8 ppm after the end of the second injection. The use of a Kalman filter therefore makes it possible to reconstruct the true boron concentration on the basis of the dilution and boron addition flows, but also on the basis of measurement of the boron concentration, in a very satisfactory way. Because the information on boron concentration in the primary circuit is obtained without delay and with reduced noise, applications in which this information has to be compared with other information can take place faster and the comparison can be more detailed. Thus for example, in a monitoring system which involves a neutron calculation model, the estimated boron concentration is compared with the theoretical boron concentration calculated in order to check the behaviour of the neutron model. The boron concentration can also be compared with a threshold in order to detect reactivity accidents, such as untimely dilution In addition to this, calculation of the volumes of water or concentrated boron solution which have to be injected by operators based on estimated boron concentration will be more accurate. It is to be expected that the core of the reactor will be controlled through finer actions, so that there will be fewer injections of charges into the primary coolant, and therefore that the volume of radioactive effluents produced by these injections will be reduced. Furthermore, resort to chemical determination by sampling the primary coolant may also be reduced. These determinations are particularly longwinded. In particular, during periodical tests, where an accurate measurement of boron concentration is required, the number of samples which have to be taken and analysed will be smaller. This will result in an appreciable time saving. The process described above may have many variants. The process may be applied to estimation of the concentration of a chemical element in the primary coolant of a reactor other than boron. The process may be applied to any type of nuclear reactor in which the concentration of a liquid element in the primary coolant is controlled by the injection of a dilution solution or a concentrated solution of the said chemical element. In the process it is possible to consider that the injections of dilution solution and concentrated solution all take place with the same predetermined flow. In this case the stage of acquiring quantities representing the flows for injection of dilution solution and concentrated solution are limited to merely establishing at each step whether or not the injection of dilution solution from the REA circuit is in progress or whether or not the injection of concentrated solution from the REA circuit is in progress. Likewise, the duration of each time step Δtk may be regarded as being constant, or can be regarded as being variable. The concentration C* of the concentrated solution is not necessarily equal to 7000 ppm, and may be different. The stage of initialising the process may be carried out in many ways. It may be carried out as described above using the first measurement made by the sensor, but in a non-preferred way it may also be carried out by considering the mean of the measurements made by the sensor over a particular period of time, or even by arbitrarily fixing the concentration value at a given value. The dilution solution may be a solution which is virtually wholly free of the chemical element, for example technically pure water, or may be a solution containing a small concentration of the chemical element in comparison with the primary coolant, for example a concentration of less than 100 ppm. Switching between the two forms of the state and measured parameters in the first calculation sub-stage may be carried out not only on the basis of whether the flow of concentrated solution is zero or not, but rather on the basis that the quantity qc representing this flow is or is not lower than a predetermined limit. This limit is chosen to be small in comparison with a nominal injection flow for the concentrated solution.
	abstract	In a pattern definition device for use in a particle-beam processing apparatus a plurality of apertures (21) are arranged within a pattern definition field (pf) wherein the positions of the apertures (21) in the pattern definition field (pf) taken with respect to a direction (X, Y) perpendicular, or parallel, to the scanning direction are offset to each other by not only multiple integers of the effective width (w) of an aperture taken along said direction, but also multiple integers of an integer fraction of said effective width. The pattern definition field (pf) may be segmented into several domains (D) composed of a many staggered lines (pl) of apertures; along the direction perpendicular to the scanning direction, the apertures of a domain are offset to each other by multiple integers of the effective width (w), whereas the offsets of apertures of different domains are integer fractions of that width.
	summary
044709480	description	DETAILED DESCRIPTION OF THE EMBODIMENT The apparatus shown in FIG. 1 is nuclear-reactor power apparatus 11. This apparatus includes a nuclear reactor 13, a pressurizer 15, and a steam generator 17. Reactor coolant is pumped through the reactor 13 by a pump 19. The coolant flows in a primary loop 21 extending from the reactor, though the hot leg 23, the inlet plenum 25 of the steam generator 17, the primary U-tubes 27 of the steam generator 17 (or straight through tubes), the outlet plenum 29 of the generator, the pump loop seal 31, the pump 19, the cold leg 33 of the loop, to the reactor. The steam generator 17 has a secondary system in heat-exchange relationship with the tubes 27 containing the reactor coolant which produces and conducts steam to the turbines (not shown) of the nuclear-reactor power apparatus. Instruments 35 and 37 are connected to the hot and cold legs 23 and 33 of loop 21. These instruments are connected to another instrument 39 which produces a measurement of the minimum temperature sensed by instruments 35 and 37. There is also an instrument 41 for measuring the temperature of the loop seal 31 and an instrument 43, connected to the hot leg for measuring the pressure of the coolant. The coolant flows into and out of the pressurizer 15 through a surge line 45 connected to the hot leg 23. There is an adder 46 for producing a signal, .DELTA.T.sub.o, measuring the difference .DELTA.T.sub.o between the temperature, T.sub.SG, of the secondary fluid and the temperature T.sub.RCS, of the coolant. T.sub.RCS is derived from instrument 39 which indicates the minimum temperature measured by instruments 35 and 37. There is also an adder 48 for measuring the difference, .DELTA.T.sub.1, between T.sub.RCS and the temperature T.sub.LS of the pump loop seal measured by instrument 41. Where there are a plurality of steam-generator loops, .DELTA.T.sub.o and .DELTA.T.sub.1, may be derived from each loop and used, with or without auctioneering, to control an equal number of valves or a lesser number of valves. The word auctioneering means the selection of a particular .DELTA.T.sub.o and .DELTA.T.sub.1, which is the most limiting signal. The nuclear reactor power apparatus 11 includes a conventional chemical and volume control system 47 which is connected to the coolant loop 21. The coolant loop 21 is supplemented from this system 47 by charging pump or pumps 49 which is connected to cold leg 33. Excessive coolant in loop 21 is dumped into this system from the loop seal 31 through valve 51 when this valve is opened. Coolant is also pumped into the cold leg 33 when necessary through the safety-injection line 53. A signal indicating when the pump 19 is started up is derived from the pump through line 56. Improper operation of the pump or pumps 49 or valve 51 or inadvertent supply of mass to the coolant through line 53 may produce a malfunction in the water-solid state of the apparatus 11. The pressurizer 15 includes electrical heaters 55 for heating the coolant contained in the pressurizer under normal power conditions. Inadvertent operation of heater 55, while coolant is water solid, can also produce a heat input overpressure transient. There is also a nozzle 57 or a plurality of nozzles near the top of the pressurizer, connected to the cold leg 33 through a valve 59 for spraying coolant into the pressurizer under normal operating conditions. The pressurizer 15 is provided with a plurality of safety valves 61 (only one shown) which are interposed in safety lines 63 connecting the pressurizer to pressurizer relief tank 65. There is also a power-actuable relief valve or valves 67 which is interposed in a relief line 69 between the pressurizer and the tank 65. When the relief valve 67 is opened, steam or water from the pressurizer 15 is dumped into tank 65. Relief valve 67 is actuated by air which is supplied through solenoid valve 71. With solenoid valve 71 closed, air from relief valve 67 is vented through vent 73. When the solenoid is energized, vent 73 is closed and control air is injected through valve 71 to open relief valve 67. Instruments 75 and 77 are connected to the pressurizer to measure its pressure and the level of the coolant therein. The pressure measurement signal is impressed on a conventional proportional plus integral plus differential (PID) controller 79. This controller 79 transmits the conventional commands and also a command to control the power-actuable relief valve 67 (FIG. 9). The nuclear power apparatus 11 according to this invention includes control logic 81 for controlling the power-actuable relief valve 67 when the apparatus is in water-solid condition. As indicated, this control logic 81 receives the temperature, pressure, level, pump start up, .DELTA.T.sub.o, .DELTA.T.sub.1 signals from the components of the apparatus which signals serve as criterians for the actuation of relief valve 67. Mass input command A and heat-input command B, derived from these signals, when they are produced, are transmitted to the relief valve control 83. The PID command from PID controller 79 is also impressed on this control 83. Under the command of the highest of signals A, B or PID, the control 83 energizes the solenoid valve 71 and the relief valve 67 with command C. In FIGS. 2 and 3, coolant 85 is represented by cross-hatching and steam 87 by dots. As shown in FIG. 2 there is during normal operation a large steam bubble 87 above the level of the coolant in pressurizer 15. In the water-solid state the pressurizer is filled with coolant 85 as shown in FIG. 3 or the volume of the bubble is very small; i.e., the level of the water is above the setpoint. Typically the reactor 13 supplies a plurality of steam generators. Each steam generator is supplied from a separate loop 21 including the components shown in FIG. 1 except for the pressurizer 15 and its components. The pressurizer is connected to hot leg of only one of the loops. Tyically the control logic 81, the relief-valve control 83 and the PID controller 79 are components of a computer. FIG. 4 shows the region of operation of the reactor apparatus 11 to which this invention is applicable. Coolant temperature, T.sub.RCS, (the minimum coolant temperature) is plotted horizontally and coolant pressure, P.sub.RCS, vertically. The curve C1 marks the coolant-pressure limit of reactor vessel 13 as defined by Appendix G; i.e., the pressure below which it is required that the apparatus operate at a corresponding coolant temperature. The curve C1 can be substantially flat below a temperature T2.sub.RCS. This invention is applicable at all coolant temperatures below the setpoint T1.sub.RCS for which the limit of Appendix G must be observed. Above this temperature the conventional protective devices of the reactor power apparatus take over. FIG. 5 shows the part of the control logic 81 (FIG. 1) from which the command A for actuating the power-actuable valve 67 for mass input is derived. The logic shown in FIG. 5 includes AND 91 which has inputs 92, 94, 96. The coolant-pressure signal is impressed on a time-derivative component 93 which derives the rate of change of pressure level anticipatory of overpressurization. The output of the time-derivative component 93 is impressed on an adder 95. The negative coolant pressure-rate setpoint is also impressed on this adder. If the coolant-pressure rate is positive, the difference between the coolant-pressure rate and the setpoint is impressed on a threshold gate 97 which passes a signal only if this difference becomes zero or exceeds a predetermined threshold. The signal from gate 97 is impressed on input 92 of AND 91 through a timer 99. The timer 99 is set to impress the signal on AND 91 only if it persists for a time interval .tau..sub.1. The time .tau..sub.1 is long enough to prevent actuation of the relief valve 67 for short, spurious transients. This is illustrated in FIG. 6. Time is plotted horizontally and coolant pressure vertically. The curve C2 for the pressure is seen to have a hump manifesting an increase in coolant pressure for short spurious transients. As shown, the interval .tau..sub.1 starts when the pressure starts to increase. The rate of increase is the slope of the line labelled dP/dt. If dP/dt equals the setpoint or exceeds it by a threshold for an interval longer than .tau..sub.1 the signal from gate 97 is impressed on AND 91. For curve C2 as illustrated by FIG. 6, the rate dP/dt is not positive for the interval .tau..sub.1 and the signal would not be impressed on AND 91. For curve C8, (FIG. 6), the rate dp/dt is positive for a time greater than interval .tau..sub.1 and the signal wound be impressed on AND 91. Another signal is impressed on input 94 of AND 91 if the coolant temperature is less than a setpoint. If this temperature exceeds the setpoint, the apparatus is in normal operation and coolant pressure is monitored by the conventional monitoring components of the nuclear power apparatus 11. A third signal is impressed on input 96 of AND 91 if the pressurizer liquid coolant level is above a setpoint; i.e. if a water solid condition potentially exists. If all these signals and signal 92 are impressed, AND 91 outputs a command A to the relief valve control 83 to actuate relief valve 67. FIG. 7 shows the logic, included in control logic 81 (FIG. 1), for actuating the relief valve 67 for excessive heat input (HI) into the coolant. FIGS. 8A and 8B show the effects on coolant temperature and coolant pressure of typical heat input into the coolant during a reactor-coolant pump start-up with secondary fluid temperature at times greater than primary coolant temperatures. In both views time is plotted horizontally. The intersection of any vertical line with the time axes of FIGS. 8A and 8B marks the same instant of time for both graphs. In FIG. 8A temperature is plotted vertically. Curve C3 represents the temperature of the secondary fluid and curve C4 the temperature of the coolant. In FIG. 8B coolant pressure is plotted vertically; the pressure follows curve C5. It is assumed that prior to t.sub.0, the apparatus 11 was shut down and put into a water-solid configuration after the load on this apparatus was removed. In proceeding to complete shut down of the apparatus, the coolant cools at a higher rate than the secondary fluid. Prior to coolant pump startup, at instant t.sub.0, the secondary fluid is at a higher temperature than the coolant as shown by curves C3 and C4 in FIG. 8A. With pump startup, coolant flows into the primary tubes of the warmer steam generator promoting flow of heat from the secondary fluid into the coolant. The pressure of the coolant increases as shown by curve C5 of FIG. 8A. The interchange of heat between the secondary fluid and the coolant continues until the system reaches equilibrium as shown by the ends E1 and E2 of curves C3 and C4 and C5. The invention involves the operation of the apparatus 11 prior to stabilization or equalization of secondary and coolant temperatures. If the pump 19 is enabled at time t.sub.o under the temperature conditions shown in FIG. 8A, there is potential for overpressurization. The apparatus shown in FIG. 7 includes an AND 101 having inputs 105, 107, 109 and 111 and an OR 103 having at least two inputs. AND 101 operates as a gate which can pass its signal, for 107, 109, 111 "high" or 1, only if there is an appropriate signal (a "high" or 1) on input 105. This input 105 receives an appropriate signal 56 (FIG. 1) from pump 19 (FIG. 1) when it starts. The signal is impressed through timer 108. Timer 108 permits the appropriate signal to be impressed only during the interval .tau..sub.2. This interval .tau..sub.2 is the interval between t.sub.0 (FIGS. 8A, 8B), the time of startup and the time when apparatus 11 reaches the equilibrium state represented by ends E1 and E2 of curves C3, C4, C5. Assuming that there is an appropriate signal on input 105, three additional conditions must be met to produce a command B to actuate relief valve 67 responsive to heat input. A signal (1 or "high") is impressed on input 107 if the pressurizer coolant level exceeds the setpoint; i.e., if apparatus 11 is potentially in water-solid state. A signal (1 or "high") is impressed on input 109 through OR 103 either if the temperature difference .DELTA.T.sub.o, namely, the temperature of the secondary fluid (C3 FIG. 8A) less the temperature of the coolant (C4), is greater than a setpoint or if the temperature difference .DELTA.T.sub.1, namely, the temperature of the coolant T.sub.RCS (FIG. 1) less the temperature of the pump loop seal 31, is greater than a setpoint. An appropriate signal is impressed on input 111 if the coolant temperature is less than a setpoint. If inputs 107, 109 and 111 receive appropriate signals while there is an appropriate signal on 105, AND 101 produces a heat input (HI) command B output and relief valve 67 is opened. Commands A or B impress a command to open relief valve 67 through OR 113 and comparator 115 (FIG. 9). Commands A or B or both are impressed on comparator 115. In addition the command from the PID controller is impressed on the comparator. The comparator transmits a command to actuate the relieve valve for the highest command impressed on it. While a preferred embodiment of this invention has been disclosed herein, many modifications thereof are feasible. This invention is not to be restricted except insofar as is necessitated by the spirit of the prior art.
	summary
044371888	summary	BACKGROUND OF THE INVENTION The invention relates to an X-ray emitting assembly for radiological equipment. The installation of radiology equipment comprising an X-ray emitting assembly poses a number of problems, among which in particular is the alignment of the operating axes of each of the associated elements. The X-ray emitting assembly, generally situated above an examination table, cooperates with at least one X-ray detector situated under the examination table; this being for example a luminance amplifier or a seriograph or a radiographic cassette. In all cases, this X-ray detector is the only element whose position, in the equipment stand, may be considered as centered from the outset; the X-ray emitting assembly must then be positioned so that the X-ray beam which it emits produces a radiation field perfectly centered on the upper plane of the selected X-ray detector. An important difficulty resides in the fact that the X-ray source is rarely perfectly aligned with the axis of the window of the sheath in which it is mounted; for this reason, the device for limiting the beam, which is generally a diaphragm, fixed directly to the sheath by mechanical guide marks, does not ensure the geometrical qualities required for the beam. This defect must be compensated for by varying the relative positions of the sheath assembly and of the diaphragm, so that the axis of the beam coincides with the reference direction of the X-ray beam. Taking into account also the considerable masses to be handled, these conditions make the alignment operations long and difficult and not without risk for the technician, considering the relatively long X-ray emission times required for these adjustments. These problems are again met with to the same extent during replacement for any reason whatsoever of the sheath assembly or of the diaphragm. The present invention relates to an X-ray emitting assembly, the arrangement of which allows some of the drawbacks of the known equipment to be resolved. This arrangement allows more especially the above described alignment problems to be resolved with simple and easily handled means. SUMMARY OF THE INVENTION The invention provides then an X-ray emitting assembly, comprising a flange for assembling a sheath assembly and a beam limiting device, operationally associated with one or more radiation detectors situated in a radiology stand, said flange being arranged to cooperate with alignment means, so as to determine, in a first stage, the positioning of this flange with respect to the operating axis of one of the radiation detectors and, in a second stage, to allow alignment along this axis of the operating axes of the sheath assembly and of the beam limiting device.
054385989	description	DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, it is seen in FIG. 1 that the invention is generally indicated by the numeral 10. Combined lower end fitting and debris filter 10 is a lower end fitting 12 for a nuclear fuel assembly that is formed from a single cast piece. Lower end fitting 12 is provided with an anti-straddle bar 14 at each corner that serve to indicate whether the fuel assembly is properly installed in the reactor. Lower end fitting 12 also contains a plurality of bores 16 therethrough for guide tubes and a central bore 18 therethrough for an instrument tube. Lower end fitting 12 is a single cast piece having a plurality of interconnected ribs 20(best seen in FIG. 2) at least five-eighth inch thick and a plurality of membranes 22 between ribs 20 that have a thickness of approximately 0.080 inch. The ribs provide the necessary structural integrity during a loss of coolant accident. Coolant flow holes 24 are cast in membranes 22 during the casting of lower end fitting 12. Coolant flow holes 24 are sized to act as a filter in the coolant stream to prevent potentially damaging debris from flowing past lower end fitting 12 to the fuel rods. For ease of illustration, and because the size and arrangement of flow holes 24 will be dependent upon the fuel assembly in which lower end fitting 12 and debris filter 10 is used, only a sampling of flow holes 24 are shown in FIG. 1. It should be understood that membranes 22 and flow holes 24 are spaced across the entire surface of lower end fitting 12 and that the partial cut away view is for the purpose of illustrating the single piece nature of lower end fitting 12 and debris filter 10. As seen in the side sectional view of FIG. 2, flow holes 24 are preferably larger at their lower end and are tapered inwardly in the direction of coolant flow through flow holes 24. This reduces pressure drop of coolant flow across flow holes 24 while maintaining acceptable filtration characteristics. The cast one-piece lower end fitting and debris filter provides for a simpler and less expensive structure than the multi-piece debris filters and end fittings currently in use. Because many varying and differing embodiments may be made within the scope of the inventive concept herein taught and because many modifications may be made in the embodiment herein detailed in accordance with the descriptive requirement of the law, it is to be understood that the details herein are to be interpreted as illustrative and not in a limiting sense.
	abstract	It is an object of the present invention to provide a technique capable of accurately inspecting a circuit pattern in which the contrast of an observation image is not clear, like a circuit pattern having a multilayer structure. A pattern inspection method according to the present invention divides a circuit pattern using the brightness of a reflection electron image and associates the region in the reflection electron image belonging to each division with the region in a secondary electron image.
048266302	description	DETAILED DESCRIPTION OF THE INVENTION FIG. 1 shows a neutron-absorber rod 21 including inner hollow cylinder 23 and outer hollow cylinder 25. These cylinders are sealed at their ends and define an annular chamber 27 in which pellets 29 made in accordance with this invention are stacked coaxially with the cylinders. Orr application shows the rod 21 in more detail. FIG. 1 shows typical dimensions of the cylinders 23 and 25 and the pellet 29. It is emphasized that the diameters of the cylinders must be maintained to within plus or minus 0.0015" and the diameter of the pellet to within plus or minus 0.002". This invention concerns itself with the producing of these pellets to size with a minimum of grinding or other machining processes. The pellets 29 are ceramics produced by following the steps shown in the flow chart of FIG. 2. In the first step 31 the Al.sub.2 O.sub.3 and B.sub.4 C powders are mixed. The starting mean size of the B.sub.4 C powder is about 1 to 30 microns; 5 to 15 microns mean size is preferred. The starting mean size of the Al.sub.2 O.sub.3 is 1 to 20 microns. To homogenize the powders and eliminate coarse agglomerates several hundred microns in size, the powders are milled and ground in a ball mill in the second step 33. This process permits intimate mixing of the constituents Al.sub.2 O.sub.3 and B.sub.4 C. To aid in the comminution and homogenation, the powders are mixed in a liquid, typically deionized water. Small but effective quantities of a wetting agent, surfactant and deflocculant are added to the liquid. A small but effective quantity of a thixotropic agent may be added. The surfactant aids in imparting wetting qualities to the liquid. The deflocculant suppresses the formation of agglomerates. The thixotropic agent imparts a fluid property to the powder when it is agitated preventing the larger particles from settling out. The powders are milled for about 1 to 2 hours producing a slurry including about 40% by weight of the powder. Organic binders and plasticizers are added to the slurry in the third step 35 and the milling is continued for 1/2 hour to 1 hour. The binders and plasticizers may also be added earlier in the processing, in the first or second step 31 or 33. The slurry is then spray dried in the next step 37 and screened in step 39. The screening eliminates large agglomerates from the powder. The result of the drying and screening is to produce free-flowing spheres of 30 to 50 microns mean diameter. The spheres are predominantly Al.sub.2 O.sub.3 with B.sub.4 C particles embedded therein. The spheres may be smaller than 30 microns or larger than 50 microns, depending on the spray-drying equipment or its operation. Typically the slurry is spray dried in a centrifugal-separator apparatus 41 as shown in FIG. 3. Such apparatus may be procurred from Niro Atomizer, Inc., Columbia, Md. This apparatus 41 includes a chamber 43 mounted on a movable support 45 formed of metal tubes. Under the top 47 of the chamber a rotatable centrifugal atomizer 49 is mounted. A feed device 51 for the slurry, which may be a hopper or the like, is mounted above the top 47 and is connected to the atomizer 49 through conductor 53. Heated air is supplied to dry the slurry emitted by the atomizer 49. The air is heated by a gas heater 55 and an electric heater 57 and flows to the region around the atomizer 49 through a conductor 59. Arrows 61 show the path of the heated air. The resulting mixture of gas and particulate flows through the chamber 43 and through conductor 63 as shown by the arrows 65 to a cyclone 67. The powder is separated from the gas in the cyclone and is deposited in container 69. An exhaust fan 71 controlled by a damper 73 is provided for exhausting the air as represented by the arrows 75. The air heated by the heaters 55 and 57 enters the chamber 43 at a temperature of about 300.degree. C. and is at a temperature of between 100.degree. C. and 125.degree. C. in the region of the atomizer 49. In the next step (77, FIG. 2) the dried powder is poured into a mold 79. The mold 79 (FIGS. 4-9) is of the multiple type. It includes a body 81 in which there are a plurality of cavities 83 (7 in the mold shown in FIG. 4). The mold 79 is formed of a material such as polyurethane which is capable of transmitting pressure. The mold with its cavities may itself be formed by molding in a die. Each cavity 83 is cylindrical terminating at the top in an expanded volume 85 (FIG. 5) of circular cross section capable of accommodating a funnel 87 (FIGS. 6,7,8) for depositing the powder. The diameters of the cavity 83 are precisely dimensioned. Typically the core which forms the lower portion of the cavity has a diameter which is maintained to plus or minus 0.001 inch. The diameter of this core in the lower region is typically about 0.430 inch. A rod or mandrel 89 is precisely centered in each cavity 83. Each rod is composed of tool steel and is precisely dimensioned. The length of the rod 89 which is typically about 8 inches, for a cavity of about 7 inches in length, is maintained within plus or minus 0.001 inch; its diameter is maintained within plus or minus 0.001 inch. Typical diameters of the rod 89 are 0.2870 inch and 0.2830 inch. The funnel 87 (FIGS. 6, 7) includes an outer shell 91 and an inner cylinder 93. The shell 91 and cylinder 93 are connected by radial plates 95. The inner diameter of the cylinder 93 typically is a slip fit on the rod 89 which extends into it. Typically the outer diameter of the cylinder 93 is 0.400 inch and is maintained to within plus 0.020 inch and minus 0.002 inch. The rod 89 is aligned in each cavity by the cylinder 93 and a precisely dimensioned groove 94 (FIG. 5) in the base of each cavity 83. The projection from the core which forms the groove 94 has a diameter which is maintained to within plus or minus 0.0005 and a height which is maintained to within plus or minus 0.005. Typically this diameter is 0.3100.+-.0.0005 inch and this height is 0.125.+-.0.005. The outer shell 91 includes a tapered section 95 interposed between a cylindrical section 97 above and a thickened short cylindrical section 99, from which a cylindrical lip 101 extends, below. The lip 101 is a slip fit in the upper rim of the wall 103 of the expanded volume 85 of the cavity (FIG. 8). When the powder is to be deposited in the cavities 83, the mold is placed in a cylinder 105 (FIG. 8). The cylinder is a slip fit on the mold 81 and serves to maintain the mold rigid and to prevent the walls of its cavities 83 from becoming deformed. The mold 81 and cylinder 105 are vibrated on a vibrating table or the like while the powder 107 (FIG. 5) is being deposited in the cavities 83 through the funnel 87. The vibration distributes the powder 107 so that it is deposited uniformly in each cavity in the annular space between the rod 89 and the cylindrical wall of the cavity. The powder is deposited along this annular space up to the junction 109 of the cylindrical portion of the cavity and the start of the taper 111 to the space of larger volume 83. The funnel 87 is removed after the powder is deposited. The rod 89 is then maintained aligned by the powder 107 and the groove 94. After the funnel is removed a plug 113 (FIG. 9) of polyurethane or the like is inserted in the opening 85. The plug is a slip fit in the wall 103 of this opening. The plug 113 has a central wall 115 onto which the top of rod 89 is a slip fit. The next step 121 (FIG. 2) is to compress the powder in the cavities 83 to form green bodies of tubular configurations. The green bodies are porous and the percent of theoretical density is evaluated. The higher the percent of theoretical density the less shrinkage of the tube during sintering. To produce the green bodies, cavities 83 are closed by plugs 113 and the mold 81 is placed in an isostatic press. Such a press can be procured from Autoclave Engineers, Inc. of Erie, Pa. The pressure may vary from 5,000 to 60,000 pounds per square inch. A pressure of 30,000 pounds per square inch is convenient. This pressure is the limit of most typical isometric presses. It has been found that the increase in percent of theoretical density of the green body with increasing pressure is not significant. This is demonstrated by the graph shown in FIG. 10. This graph was produced by compressing masses of Al.sub.2 O.sub.3 into green bodies by applying different isostatic pressures and measuring the percent of theoretical density for each pressure. Percent theoretical density is plotted vertically and pressure horizontally. The percent theoretical density of the body compressed at about 10,000 psi was 50 as compared to 60 at about 80,000 psi. A change of 1,000 psi produces only 0.14 change in the percent of theoretical density. The data on the Al.sub.2 O.sub.3 applies to mixtures of Al.sub.2 O.sub.3 and B.sub.4 C. In the next step 123 (FIG. 2) the green body is presintered at a temperature sufficient to remove the organic binder and plasticizer. This step is optional. The presintering step is followed by a sintering step 125. The sintering is at a temperature between 1400.degree. C. and 1800.degree. C.. During sintering the atoms of the Al.sub.3 O.sub.3 matrix diffuse and the mass shrinks. The B.sub.4 C particles remain essentially unchanged. The sintering should be carried out in such manner that the resulting body is sintered to size requiring only a minimum of external grinding. It is necessary to form the pellets so as to prevent excessive swelling and possible destruction of the pellets by reason of neutron bombardment and release of helium gas during reactor operation. The sintering should be carried out so that the pellets are porous. Typically the porosity should be such that the density of the pellets is equal to or less than 70% of theoretical density. The porosity should be open so as to permit evolution of the helium. Since the density is substantially less than theoretical density, it is necessary to control the percent theoretical density accurately for all boron loadings to a predetermined magnitude. It is necessary to ensure that the green bodies sinter identically, or at least predicatably, from batch to batch and lot-to-lot so that the shrinkage during sintering can be controlled to obtain sintered tubes of requisite dimensions. This object is achieved by maintaining the same powder compositions and green body density during pressing and to use the same sintering schedule including temperature, environment and time of sintering. The powders which are used must be of consistent quality. It has been found that to achieve the desired relatively low percent of theoretical density (.ltoreq.70%), the sintering should take place in an inert gas such as argon at about atmospheric pressure. By sintering in argon the percent of theoretical density can be controlled over a wide range of B.sub.4 C content. There is no appreciable vaporization. Other gases present problems. N.sub.2 can only be used at relatively low temperatures and for short intervals, typically 1400.degree. C., and 3 hours. At higher temperatures or for longer times boron nitride is formed. Sintering in carbon dioxide results in oxidation of B.sub.4 C to B.sub.2 O.sub.3. Sintering in hydrogen is on the whole satisfactory but it results in lower densities of the sintered ceramic than sintering in argon. Also density of the ceramic progressively decreases with increase in temperature. Vacuum sintering can be used at lower temperatures, typically 1600.degree. C. or lower. At higher temperatures, B.sub.4 C and Al.sub.2 O.sub.3 are lost by vaporization in the vacuum. Also, control of present or theoretical density of the vacuum-sintered ceramic is not effective. FIG. 11 shows the relationship between the percent theoretical density of green bodies of Al.sub.2 O.sub.3 and B.sub.4 C and the content of B.sub.4 C in the green bodies. The Al.sub.2 O.sub.3 was powder sold under the designated A-16 by Alcoa. The sintering was carried out in argon at 1400.degree. C. and at 1500.degree. C. for 3 hours. Percent theoretical density is plotted vertically and weight percent of B.sub.4 C in the green body horizontally. The percent theoretical density rises sharply for B.sub.4 C content less than 2.5 percent but for higher B.sub.4 C content, the change is relatively small. Between 2.5 and 25%, the percent decrease is from about 70 to about 65 at 1400.degree. C. and from about 71 or 72 to about 64 or 63 at 1500.degree. C.. Neither the sintering temperature nor the content in the green body of above 2.5% of B.sub.4 C have a marked effect on the percent theoretical density. Sintering time is an important parameter where the time is substantially higher than about 3 hours. In FIG. 12 percent theoretical density is plotted vertically as a function of sintering temperature plotted horizontally. A family of curves for three times, 1 hour, 3 hours and 8 hours are presented. The curves were plotted for ceramics composed of 80% by weight of Alcoa-A16 Al.sub.2 O.sub.3 and 20% B.sub.4 C sintered in argon. The percent theoretical density is substantially the same for sintering for 1 hour and 3 hours and for sintering for 8 hours at temperatures below 1500.degree. C. But above 1500.degree. C. for 8 hours the percent theoretical density decreases sharply with increase in temperature; i.e., the porosity rises sharply. This increase in porosity results from the reaction of B.sub.4 C with the residual oxygen in the argon-forming gaseous species at the higher temperatures during the extended heating interval. It is desirable that the argon gas be as pure as practicable for higher-temperature or extended-time sintering. That the percent theoretical density may be set by appropriate selection of the Al.sub.2 O.sub.3 powder is shown in FIG. 13. In this graph percent theoretical density is plotted vertically and temperature horizontally. A family of curves is presented. Each curve is plotted for the sintering in argon of a green body composed of 80% by weight of a selected Al.sub.2 O.sub.3 and 20% B.sub.4 C. The green body with Reynolds 172-DBM manifests the lowest percent theoretical density; i.e., the highest porosity; Linde-A manifests the highest percent theoretical density. Alcoa-A16 and Reynolds HP-DBM did not differ significantly. The differences are governed by the sinterability of the powder; i.e., by the extent of the diffusion of the molecules and atoms of the powder during the sintering operation. Changes in percent theoretical density can also be effected by appropriate selection of the particle size of the B.sub.4 C. Higher percent theoretical densities of the ceramic are obtained with fine powders, typically less than 400 mesh, than with coarse powder, typically greater than 200 mesh. In the final steps, 127 and 129 the outer surface of the tube can be ground and the pellet lengths are accurately finished to length. The pellet lengths may also be cut from the green tube or from the presintered tube. If desired the green or presintered pellets can be machined to size prior to sintering. Tables I and II below show typical constituents, based on 100 grams of Al.sub.2 O.sub.3 and B.sub.4 C powder, of feed material for isostatic pressing in the practice of this invention: A slurry of the constituents in Tables I and II was formed with about 150 grams of water. Lomar is procured from Process Chemical Division, Norristown, N.J. Carbowax 200 and Ucon 2000 are procured from Union Carbide, New York, N.Y. Triton, Tamol, and Rhoplex are procured from Rohn & Hass, Pelham Manor, N.J. Santicizer is procured from Monsanto Chemical Company While preferred embodiments of this invention have been disclosed herein, many modifications thereof are feasible. This invention is not to be restricted except insofar as is necessitated by the spirit of the prior art.
	description	The present invention refers to the method of shortening the scintillation response of a scintillator for the detection of ionizing radiation and to the scintillator material with a fast scintillation response to the incident ionizing radiation. The scintillation material, that is the scintillator, absorbs ionizing particles or photons with energies sufficient for the ionization of the environment in which it is located, i.e. generally in VUV (above 7 eV) or in the more short-wave region of the electromagnetic spectrum, and emits ionizing particles or photons with lower energy in the relevant region of the electromagnetic spectrum. The absorption of ionizing radiation in any environment induces excited states of electrons of scintillator atoms, molecules or ions in the crystal lattice. The most frequently used scintillators emit the radiation in a fast, efficient and reproducible method in the visible spectrum region in the so-called scintillation response, that is in the scintillation decay, as a reaction to the absorption of ionizing radiation which is generally outside the visible spectrum region. This means that the scintillator converts the electromagnetic radiation of any wavelength and frequency that the human eye (detectors) may not be sensitive to, into the radiation which is visible to the human eye (detectors). Most scintillators react to various forms of ionizing radiation. The ability to absorb the electromagnetic radiation is characterised by the absorption spectra of substances and the ability to emit the electromagnetic radiation is characterised by the emission spectra of substances. To asses the absorption or emission spectra, or the absorption or emission bands in them, the maximum value is utilised that the individual bands achieve, and the full width at half maximum (FWHM) which is given by the difference between the two extreme values that are independently variable, at which the dependent variable is equal to half of its maximum value. Half width at half maximum (HWHM) equals half of FWHM. The primary dominant time is the fastest amplitude-dominant component in the scintillator response, determined by the emission centre lifetime which is very close to the lifetime in the photoluminescent decay. The photoluminescent decay is measured at the direct excitation of the emission centre, typically in the ultraviolet spectrum region. The scintillation response practically always contains slower components, too, that originate as a result of energy transfer, mostly in the form of the charge carriers migration towards emission centres. Scintillators are often utilised during detection and spectrometry of various forms of ionizing radiation. These detectors are frequently used in the area of research in nuclear and particle physics, in medicine or in industry for quality control. Many of these applications require a short scintillator decay time because it is directly proportional to the speed of the technical operation that the scintillator performs. The examples of technical operations where the scintillator decay time plays a critical role include patient's body scanning in PET, i.e. positron emission tomography, scanning objects at border control, detection of particles in studies in particle physics, scanning and imaging in electron microscopy and CT, crystallography and many others. Currently, various types of single crystals are being used for the preparation of scintillation detectors. Depending on the requested applications, various physico-chemical, material and scintillation properties of the individual types of the single crystals are used, such as the density, effective atomic number, wavelength emission, luminescent lifetime and light yield. In industry the materials based on aluminates have been in use for a long time, namely, the Yttrium Aluminium Garnet doped with Ce3+ (YAG:Ce, Y3Al5O12:Ce), Yttrium Aluminium Perovskite doped with Ce3+ (YAP:Ce, YAlO3:Ce) or Yttrium Silicate doped with Ce3+ (YSO:Ce, Y2SiO5:Ce). Should a higher density and effective atomic number be required, the Y ion is completely or partially replaced with the Lu ion. The speed of detector scintillation response is limited by the response of the luminescence centre itself cerium ion, which is between 20-70 ns for these materials. An example of a relatively fast scintillator which is frequently used is YAG:Ce. Although the utilization of this scintillator e.g. in electron microscopy has been known minimally since 1978 (R. Autrata, P. Schauer, Jos. Kvapil, J. Kvapil—“A single crystal of YAG—new fast scintillator in SEM”—Journal of Physics E 11, (1978) p. 707-708), this scintillator is still widely used. However, its scintillator decay time is 70 ns, which is relatively long. Consequently, this scintillator is more and more replaced with faster materials, such as YAP:Ce with the decay time of 25 ns, as described in the patent documentation CZ 275476. YAP:Ce probably represents a limit material concerning the speed of decay time with cerium doped oxide materials (P. Dorenbos, Fundamental Limitations in the Performance of Ce3+-, Pr3+ and Eu2+-Activated Scintillators. IEEE Trans. Nucl. Science 57 3 (2010) 1162-1167). It is given by the lifetime of the Ce3+ luminescence centre and is furthermore influenced by the position symmetry of Y3+ which Ce3+ substitutes and by the intensity of crystalline field. In spite of this, even this value is not sufficient for some applications. For higher speed shorter decay time some applications use a material doped with praseodymium which has a shorter lifetime than that of cerium. An example includes the LuAG:Pr material from the U.S. Pat. No. 7,019,284 or LuYAG:Pr from the CZ300631 patent which has the decay time of approximately 20 ns. But even this value is not sufficient in some examples of usage. Although there exist faster scintillators than these described above, such as BaF2, PbWO4 or ZnO, they do not find usage in real applications because they provide too low amount of light, i.e. small number of photons per 1 MeV of absorbed energy of ionizing radition. Therefore most efforts are focused on the modification of the above described materials. In optimized material compositions in single crystal scintillators of the above stated type, a focused co-doping has been used with optically inactive ions with a charge different from the original cation which they replace. Co-doping with the Ca2+ and Mg2+ ions is often used (M. Nikl, A. Yoshikawa, Recent R&D trends in inorganic single crystal scintillator materials for radiation detection. Adv. Opt. Mater. 3, 463-481 (2015)). Such ions do not participate in the scintillation process itself as they are neither able to catch migrating charges, nor participate as luminescence centres. These strategies result in suppressing the slower components in the scintillation response which originated due to the transport of electrons and holes towards the luminescence centres. This achieves faster scintillation response and the light yield and/or requested scintillator luminosity are preserved or even increased. The WO 2014/197099 A2 patent application describes a scintillator composed of yttrium-aluminium garnet doped with metal (YAG:M), when the general formula of the phosphor is Y3-xMxAl5+yO12+z and stoichiometric coefficients x, y and z are in various ranges. At the same time, the molar ratio Y:Al is between 1.5:2.5 and 1.5:2.75 and between Y:M it is 1.5:0.0015 and 1.5:0.15, this phosphor composition is not stoichiometric. The M letter represents a metal from the Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Cr and Lu group. Another example of a patent that modifies the known garnet structure YAG:Ce is the U.S. Pat. No. 8,969,812 patent. This patent replaces in the atom crystalline structure the aluminium atom with gallium and the yttrium, lutecium or ytterbium atoms with gadolinium. The resulting scintillator is described with a chemical formula Gd3-x-yCexREyAl5-zGazO12. X then lies in the range of 0.0001 to 0.15, y in the range between 0 to 0.1 and z in the range between 2 to 4.5. RE are the elements Y, Yb or Lu. This scintillator emits at the wavelength of 530 nm and its decay time depends on various chemical compositions and relations between the individual elements. This scintillator can be used for a whole range of applications, such as positron emission tomography. The U.S. Pat. No. 7,405,404 B1 patent document describes the invention—a new scintillator (CeBr3) for gamma rays spectroscopy. The scintillator single crystals are prepared with the Bridgman process. In CeBr3 the trivalent cerium cation (Ce3±) represents the inner luminescent centre for the scintillation process. The crystals have a high light yield and a fast scintillation response. In other design the lutetium in LuBr3 or lanthan in LaBr3 may be utilised. Other dopants may include Eu, Pr, Sr, Ti, Cl, F, I. The dopant is present in the amount ranging from 0.1% to 100%. However, there exist such applications which require ever higher acceleration of scintillation response with a lower but still significant scintillation yield. These include applications from the area of internal material structure quality control. The task of the submitted invention is to find the method of greater acceleration of scintillation response of the scintillator than in the known scintillators. The task of the invention is also to find the scintillator material, suitable for the application of this method. The set task is solved by creating the method of shortening the scintillation response of scintillator luminescence centres and creating a scintillator material with the shortened scintillation response according to this invention. The invention concerns a scintillator which contains at least one dopant from the Ce, Pr group creating luminescent centres. The summary of the invention comprises the fact that after the excitation of the electrons of the luminescent centres as a result of absorbed electromagnetic radiation, a portion of energy from the excited luminescent centres is taken away via a non-luminescent process which results in the shortening of the time of duration of amplitude-dominant component of the scintillation response. In one preferred embodiment of the method of shortening the scintillation response of a scintillator according to this invention, the taking away of a part of energy in the non-radiative transfer is performed by the inserting of minimally one type of the first co-dopant in the structure of the scintillator material. FWHM range of the co-dopant absorption band is in the extent of ±HWHM from the wavelength of the dopant emission band maximum where HWHM is half width at half maximum of the emission band. In this method of shortening the scintillation response of a scintillator according to the invention, the first co-dopant is preferably from the group of lanthanoids, 3d transition metals, 4d transition metals or 5s2 (In+, Sn2+, Sb3+) or 6s2 (Tl+, Pb2+, Bi3+) ions. Co-doping with these ions shortens the photoluminescence response and shortens too the scintillations response in its main, dominating component. Consequently, the light yield is being decreased in the same ratio as the measured photoluminescence lifetime is being shortened, which results in accelerated scintillation response. In another preferred embodiment of the method of reducing the scintillation response of a scintillator according to this invention, minimally one second co-dopant from the group of optically inactive ions is inserted in the structure of the scintillator material. In this preferred execution the dominant component of the scintillation response is accelerated and the intensity of slower secondary components of the scintillation response is decreased at the same time. In the preferred execution the second co-dopant is the Mg2+ or Ca2+ cation. In another preferred embodiment of the method of shortening the scintillation response of a scintillator according to this invention, the taking away of a part of energy in the non-radiative transfer is performed by increasing the material temperature above the threshold value of the thermal quenching of luminescence centres, that is above the temperature when the intensity and luminescence lifetime of the emitted radiation drops to one half. The summary of the invention is also the scintillator material based on garnet with a general chemical formula A3B5O12 which corresponds to the general chemical formula A3-x1-x21Mx12Mx2B5O12 where substituent A is represented by a cation from the Y3+, Lu3+, Gd3+ group or their mixture, substituent B is represented by a cation from the Al3+, Ga3+, Sc3+, Mo3+ group or their mixture, substituent 1M represents the dopant cation from the Ce3+ or Pr3+ group and substituent 2M represents the first codopant cation from the Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm lanthanoids group or from the Ti, V, Cr, Mn, Fe, Co, Ni, Cu 3d transition metals group or from the Zr, Nb, Mo, Ru, Rh, Ag 4d transition metals group or from the Ta, W 5d transition metals group or from the 5s2 In, Sn, Sb ions group or from the 6s2 Tl, Pb, Bi ions group. In another preferred execution the substituent 2M represents a mixture of the first co-dopant and the second co-dopant where the second co-dopant is from the group of optically inactive ions, Mg2+ or Ca2+ cation. The summary of the invention is also the scintillator material based on perovskite with a general chemical formula ABO3 which corresponds to the general chemical formula A1-x1-x21Mx12Mx2BO3 where substituent A is represented by a cation from the Y3+, Lu3+, Gd3+ group or their mixture, substituent B is represented by a cation from the Al3+, Ga3+, Sc3+, Mo3+ group or their mixture, substituent 1M represents the dopant cation from the Ce3+ or Pr3+ group and substituent 2M represents the first codopant cation from the lanthanoids group, 3d transition metals, 4d transition metals, 5d transition metals group or 5s2 or 6s2 ions. In the preferred embodiment the substituent 2M represents the first co-dopant from the Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm lanthanoid group or from the Ti, V, Cr, Mn, Fe, Co, Ni, Cu 3d transition metals or from the Zr, Nb, Mo, Ru, Rh, Ag 4d transition metals or from the Ta, W 5d transition metals or from the 5s2 In, Sn, Sb ion group or from the 6s2 Tl, Pb, Bi ion group. The summary of the invention is also the scintillator material based on silicate with a general chemical formula A2SiO5 which corresponds to the general chemical formula A2-x1-x21Mx12Mx2SiO5 where substituent A is represented by a cation from the Y3+, Lu3+, Gd3+ group or their mixture, substituent 1M represents the dopant cation from Ce3+ or Pr3+ group and substituent 2M represents the first codopant cation from the lanthanoids group, 3d transition metals, 4d transition metals, 5d transition metals group or 5s2 or 6s2 ions. In the preferred embodiment the substituent 2M represents the first co-dopant from the Nd, Sm, Eu, Tb, Dy, Ho, Er, Tm lanthanoid group or from the Ti, V, Cr, Mn, Fe, Co, Ni, Cu 3d transition metals or from the Zr, Nb, Mo, Ru, Rh, Ag 4d transition metals or from the Ta, W 5d transition metals or from the 5s2 In, Sn, Sb ion group or from the 6s2Tl, Pb, Bi ion group. In another preferred execution the substituent 2M represents a mixture of the first co-dopant and the second co-dopant where the second co-dopant is from the group of optically inactive ions, Mg2+ or Ca2+ cation. The advantages of the invention may include the reducing of the scintillation response time of the scintillator, especially the acceleration of the scintillation response dominant component which is given by the luminescence centre itself whereas a high scintillation yield does not necessarily have to be preserved. It is understood that the below stated and depicted specific examples of the invention execution are represented for illustration and not as the limitation of the invention to the stated examples. Experts knowledgeable of the state of technology will find or will be able to ensure, when performing routine experimentation, larger or smaller amount of equivalents to the specific executions of the invention which are described here. These equivalents shall be also included in the extent of the following patent claims. Active scintillators may be prepared in the form of powder, such as via simple sintering, of an active layer, such as via epitaxial growth or plasma deposition, or of a volume single crystal, such as with the Czochralski, EFG, microPD, Kyropoulos and other methods. The scintillation response mechanism with known materials is schematically illustrated in FIGS. 1-3 with the example of the LuAG:Ce garnet material. Ce3+ is used as a dopant here. In FIG. 1, the A curve represents the response of the Ce3+ centre which is excited directly with photons of the 450 nm wavelength, the B curve represents the scintillation response of the Ce3+ centre which is excited with ionizing radiation, i.e. gama photons with the 511 keV energy. In the scintillation response, there is marked the amplitude-dominant fast component 1, which is determined by the emission centre lifetime and where the A and B curves are practically identical, and the following amplitude-minor slow component 2 of the scintillation response arising as a result of the migration of charge carriers to the Ce3+ centres. FIG. 2 illustrates a graph of absorption spectrum of the same material, i.e. LuAG:Ce, with marked maximum 4 of the absorption band and width in the half of absorption band maximum related to the Ce3+ centre in the LuAG:Ce scintillator. This width is designated as half width FWHM. The graph depicts the dependence of absorbance on the wavelength with marked absorption transition of Ce3+ between the 4f and 5d1 levels. FIG. 3 illustrates a graph of luminescence spectrum with marked maximum 3 of the emission band and half width of emission band (FWHM) related to the Ce3+ centre in the LuAG:Ce scintillator, depicting the dependence of normalised intensity on the wavelength. FIG. 1 clearly shows that the scintillation response of known scintillators is long also due to the long duration time of the amplitude-dominant component of the scintillation response. This time is significantly shortened in materials according to the following examples of invention execution: Mixtures were prepared of Y2O3 and Al2O3 binary oxides with the Y3Al5O12 composition, CeO2 and Al2O3 with the Ce3Al5O12 composition, Nd2O3 and Al2O3 of the Nd3Al5O12 composition when the used materials were of the 5N purity. Mechanical mixing was followed with homogenisation via shaking and isostatic pressing into a block. The blocks were sintered at 1 400° C. for the period of 24 hours in the air and subsequently were partially crushed and inserted into a molybdenum crucible. The YAG:Ce, YAG:Nd and YAG:Ce, Nd single crystals were grown from the mixture via the Czochralski method under a protective hydrogen/argon atmosphere. The composing of melt for growing was selected in such a method that the resulting crystals are of the Y2.96Nd0.04Al5O12) Y2.91Nd0.04Ce9.95Al5O12 a Y2.95Ce0.05Al5O12 composition to compare their characteristics. Small discs were cut from the prepared single crystals of 1 mm thickness and 10 mm diameter which were optically polished for the subsequent measurement of the spectra and scintillation responses. FIG. 4 illustrates with the C and D curves the overlap of the emission band of the Ce3+ centre of the YAG:Ce crystal with marked maximum 3 at 525 nm and absorption transitions of the centre Nd3+ 4I9/2→4G5/2, 4G7/2 (W. T. Carnal) et al, J. Chem. Phys. 90, no. 7, 3443, 1989) in the spectrum range of 500-595 nm which corresponds to FWHM of the Ce3+ centre emission, utilizing X-ray radiation with the voltage on the X-ray tube of 40 kV. This overlap causes a non-radiative energy transfer from the Ce3+ centre to the Nd3+ centre which results in the acceleration of the amplitude-dominant component 1 in the scintillator response that is depicted in FIG. 5, where the E curve illustrates the scintillation response of the common YAG:Ce material and the F curve illustrates the scintillation response of the YAG:Ce material co-doped with Nd as the first co-dopant. Both the materials were exposed to gamma radiation with the photon energy 511 keV from the radioisotope 22Na. For the purposes of quantitative assessment of the scintillation response shortening, the 1/e life time, denoted in FIG. 5, is standardly introduced. The life time is the time of duration from which the signal drops from the maximum amplitude 1 to 1/e, where e is the base of the natural logarithm, e=2.718 in time t1, t2 and t3. The life time of the YAG:Ce, Nd F crystal is shortened to 12 ns in comparison with 61 ns of the YAG:Ce material E, that is more than four times. In the total amount of 5 g, the Y2O3, Al2O3, CeO2 and Ho2O3 binary oxides of the 5N purity were mixed in the ratio of the chemical Y2.91Ho004Ce005Al5O12 formula. After mechanical mixing and grinding in the grinding mortar there followed a two-stage sintering: in the first stage at 1 300° C. for the period of 24 hours, in the second stage at 1 400° C. for the period of 24 hours, in the air. The material was again mechanically ground in the grinding mortar between the individual steps. The powder was inserted into a molybdenum crucible and in the protective atmosphere of 70% argon/30% hydrogen a single crystal was drawn in the shape of a rod with the EFG method through a molybdenum die. The Y2.96Nd0.04Al5O12 and Y2.95Ce0.05Al5O12 single crystals were prepared in the same method to compare their characteristics. Small discs of 1 mm thickness were cut from the prepared single crystal rods of 4 mm diameter which were optically polished for the subsequent measuring of spectra and scintillation responses. The overlap of the emission band of the Ce3+ centre with maximum at 525 nm and absorption transition of the centre Ho3+ 5I8=5S2, 5F4 centre with the maximum at 530-540 nm (W. T. Carnal) et al, J. Chem. Phys. 90, no. 7, 3443, 1989) in the spectrum range of 500-595 nm which corresponds to FWHM of the Ce3+ centre emission, causes the acceleration of the amplitude-dominant component of the scintillator response which is depicted in FIG. 6, where the G curve illustrates the scintillation response of the common YAG:Ce material and the H curve illustrates the scintillation response of the YAG:Ce material co-doped with Ho as the first co-dopant. Both the materials were exposed to gamma radiation of the photon energy 511 keV from the radioisotope 22Na. FIG. 6 depicts the life time t3 of the YAG:Ce crystal with the G curve and life time t2 of the YAG:Ce, Ho with the H curve which is shortened to 25.2 ns in comparison with 61 ns of the YAG:Ce material, that is more than twice. Time t1 represents the start of the experiment. The YAP:Pr and YAP:Pr, Gd single crystals were prepared and grown analogously according to Example 2 when the Y2O3, Al2O3, Gd2O3 and Pr8O11 binary oxides of the 5N purity were mixed in the ratio of the Y0.995Pr0.005AlO3, Y0.985Gd0.01Pr0.005AlO3 and Y0.945Gd0.05Pr0.005AlO3 chemical formulas. The spectra and scintillation responses were measured analogously as in Example 2. FIG. 7 illustrates the emission band of the Pr3+ centre with marked maximum 3 at 247 nm and full width at half maximum (FWHM) related to the Pr3+ centre in the YAP:Pr scintillator. The overlap of the emission band of the Pr3+ centre with absorption transition of the centre Gd3+ 8S7/2→6Ix at 270-275 nm (W. T. Carnal) et al, J. Chem. Phys. 90, no. 7, 3443, 1989) in the spectrum range of 235-285 nm which corresponds to FWHM of the Pr3+ centre emission, causes a non-radiative energy transfer from the Pr3+ centre to the Gd3+ centre which results in the acceleration of the amplitude-dominant component 1 in the scintillator response which is depicted in FIG. 8. The YAP:Pr and YAP:Pr, Gd single crystals were exposed to gamma radiation of the photon energy 511 keV from the radioisotope 22Na. The life time of the amplitude-dominant component of the YAP:Pr, Gd single crystal is shortened in comparison with 16 ns of the YAP:Pr material, depicted with the I curve, to 11 ns for the YAP:Pr material co-doped with Gd (1% wt.) depicted with the J curve, and to 7 ns for the YAP:Pr material co-doped with Gd (5% wt.) depicted with the K curve. The life times were calculated from the convolution of the instrumental response (stated in FIG. 8) with a double exponential function. The YAP:Pr and YAP:Pr co-doped with Tb single crystals were prepared and grown analogously according to Example 1. A mixture of Y2O3 and Al2O3 binary oxides was prepared with the ratio 1:1. Mechanical mixing was followed with homogenisation shaking and isostatic pressing into a block. The blocks were sintered at 1 400° C. for the period of 24 hours in the air and subsequently were partially crushed and inserted into a tungsten crucible. To complete stoichiometry, the Al2O3, Tb4O7 and Pr6O11 oxides were used with materials of the 4N purity. Single crystal with Y0.995Pr0.005AlO3, Y0.985Tb0.01Pr0.005AlO3 and Y0.945Tb0.05Pr0.005AlO3 chemical formulas were prepared from the stated materials. The spectra and scintillation responses were measured analogously as in Example 1. The overlap of the emission band of the Pr3+ centre with maximum at 247 nm and the lowest absorption band transition 4f-5d of the Tb3+ centre in range of 250-280 nm (K. S. Sohn et al, J. Electrochem. Soc., 147 (9) 3552, 2000) in the spectrum range of 235-285 nm which corresponds to FWHM of the Pr3+ centre emission, causes a non-radiative energy transfer from the Pr3+ centre to the Tb3+ centre which results in the acceleration of the amplitude-dominant component 1 in the scintillator response. It is depicted in FIG. 9. The YAP:Pr and YAP:Pr, Tb single crystals were exposed to gamma radiation of the photon energy 511 keV from the radioisotope 22Na. The life time of the amplitude-dominant component of the YAP:Pr, Tb single crystal is shortened in comparison with 16 ns of the YAP:Pr material, depicted with the I curve from Example 3, to 11 ns for the YAP:Pr material co-doped with Td (1% wt.) depicted with the L curve, and to less than 1 ns for the YAP:Pr material co-doped with Tb (5% wt.) depicted with the M curve. The life times were calculated from the convolution of the instrumental response (shown in FIG. 9) with a double exponential function. The LGSO:Ce and LGSO:Ce co-doped with Dy single crystals were prepared and grown with the Czochralski method from iridium crucible under the protective atmosphere of nitrogen with traces of oxygen. The starting materials for growing the single crystal analogously according to Example 1 were the Lu2O3 and SiO2, Gd2O3 and SiO2, CeO4 and SiO2 and Dy2O3 and SiO2 binary oxides mixtures with the purity of 5N. The result of growth were the single crystals of the (Lu0.53Gd0.40Ce0.01)2SiO5, and (Lu0.57Gd0.40Ce0.01Dy0.02)2SiO5 chemical formulas. The spectra and scintillation responses were measured analogously as in Example 1. The overlap of the emission band of the Ce3+ centre with marked maximum 3 at 425 nm and FWHM 400-465 nm and absorption transitions 4f-4f from the basic state of 6H15/2 to higher 4f states 4I15/2 and 4G1/12 and 4M21/2 of the Dy3+ centre in the range of 400-455 nm (W. T. Carnal) et al, J. Chem. Phys. 90, no. 7, 3443, 1989), which is depicted in FIG. 10, causes a non-radiative energy transfer from the Ce3+ centre to the Dy3+ centre which results in the acceleration of the amplitude-dominant component 1 of the scintillator response. It is depicted in FIG. 11, where the N curve illustrates the scintillation response of the common LGSO:Ce material and the 0 curve illustrates the scintillation response of the LGSO:Ce material co-doped with Dy as the first co-dopant. Both the materials were exposed to gamma radiation of the photon energy 511 keV from the radioisotope 22Na. The life time t2 of the amplitude-dominant component of the LGSO:Ce crystal, co-doped with Dy, 2% wt. 0 is shortened when compared with the life time t3 of 27.8 ns of the material LGSO:Ce N to 6.1 ns, that is more than four times. Time t1 represents the start of the experiment. The YSO:Ce single crystal was prepared and grown analogously according to Example 4. The Y2O3, SiO2 and CeO4 binary oxides of 5N purity were mixed which resulted in a single crystal of the (Y0.99Ce0.01)2SiO5 chemical formula. The spectra and scintillation responses were measured analogously as in Example 1. A sufficient increase in temperature leads practically with every luminescence centre to the appearance of non-radiative thermal quenching of luminescence which can be utilized, too, for the shortening of the period of duration of the dominant component 1 in the scintillation response. In case of the emission band of both the Ce3+ centres, marked here as the P curve and the Q curve, in the host YSO crystal, the thermal quenching of both the P and Q centres occurs at approximately 350 K, as shown in FIG. 12. Around 90% of all cerium emission centres have maxima of emission at 400 nm, these emission centres are represented with the 0 curve, the P curve represents minor cerium emission centres with the emission maximum at 490 nm. FIG. 13 illustrates how the dominant component 1 in the scintillation response at 450 K is shortened approximately three times when compared to the room temperature, when YSO:Ce crystals were excited by gamma radiation of the photon energy 511 keV from the radioisotope 22Na. For the purposes of quantitative assessment of the scintillation response shortening, the 1/e life time is introduced as well as in all the previous examples. Life time t3 is 39.3 ns at room temperature (295 K) and life time t2 is 13.4 ns at 450 K, as is illustrated with the R curve (295 K) and Q curve (450 K) in FIG. 13. Time t1 represents the start of the experiment. It is clear from Examples 1 to 6 that the utilization of the first co-dopant results in a significant acceleration in the time of duration of amplitude-dominant component of the scintillation response. The scintillation response consists also of slower components where it is possible to decrease intensity. This simultaneous action occurs with materials according to the following example of invention execution: The LuAG:Ce and LuAG:Ce co-doped with Nd and LuAG:Ce doubly do-doped with Nd and Mg single crystals were prepared and grown analogously according to Example 2 when the Lu2O3, Al2O3, CeO2, Nd2O3 and MgO binary oxides of 5N purity were mixed in the ratio of the Lu2.91Nd0.02Ce0.05Mg0.02Al5O12 and Lu2.93Nd0.02Ce0.05Al5O12 and Lu2.95Ce0.05Al5O12 chemical formulas. The spectra and scintillation responses were measured analogously as in Example 2. The overlap of the emission band of the Ce3+ centre with maximum at 525 nm and absorption band transitions of the centre Nd3+ 4I9/2>4G5/2, 4G7/2 Nd3+ 4I9/2□4G5/2,4G7/2 (W. T. Carnal) et al, J. Chem. Phys. 90, no. 7, 3443, 1989) in the spectrum range of 500-595 nm which corresponds to FWHM of the Ce3+ centre emission, causes a non-radiative energy transfer from the Ce3+ centre to the Nd3+ centre which results in the acceleration of the amplitude-dominant component 1 in the scintillation response which is depicted in FIG. 14. The life time of the amplitude-dominant component of the LuAG:Ce, Nd single crystal is shortened in comparison with 66 ns of the LuAG:Ce material T to 43 ns U. Compared to the YAG:Ce crystal, the scintillation response contains significantly more intensive slow components 2, as can be seen when comparing FIG. 3 and FIG. 12. Their partial suppression may be achieved via the co-doping with the optically inactive double-valent ion (M. Nikl et al, Crystal Growth Design 14, 4827, 2014). The simultaneous application of this co-dopant results in a partial suppression in LuAG:Ce, Nd, Mg of the slow component 2 in the scintillation response in the material with accelerated dominant component 1 of the scintillation response, as illustrated in FIG. 14 where the T curve represents the scintillation response of the LuAG:Ce single crystal, the U curve demonstrates the shortening of the scintillation response of the amplitude-dominant component of the LuAG:Ce, Nd single crystal and the V curve demonstrates the shortening of the scintillation response of both the amplitude-dominant and the amplitude-minor components of the LuAG:Ce, Nd, Mg single crystal. In other example of execution, the first co-dopant can be from the 3d transition metals group—Ti, V, Cr, Mn, Fe, Co, Ni, Cu, 4d transition metals group—Zr, Nb, Mo, Ru, Rh, Ag, 5d transition metals group—Ta, W, 5s2 ions—In, Sn, Sb, or from the 6s2 ions group—Tl, Pb, Bi. In another example of execution the Ca2+ cation can be used as the second co-dopant. The Gd3Ga3Al2O12:Ce (GGAG:Ce) single crystal was prepared and grown analogously according to Example 1 when the Gd2O3, Ga2O3, Al2O3, CeO2 and Nd2O3 binary oxides of 5N purity were mixed. The GGAG:Ce single crystal was grown from the mixture via the Czochralski method under a protective hydrogen/argon atmosphere, the composition of melt for the growth was selected in such a method that the resulting crystal was composed in the ratio of the Gd2.955Nd0.03Ce0.015Ga3Al2O12 chemical formula. Analogously as in Example 1, the spectra and scintillation responses were subsequently measured. The Gd2.97Nd0.03Ga3Al2O12 and Gd2.985Ce0.15Ga3Al2O12 single crystals were prepared in the same method to compare their characteristics. FIG. 15 illustrates with the W and X curves the overlap of the emission band of the Ce3+ centre of the GGAG:Ce single crystal with marked maximum 3 at 535 nm and absorption transitions of the centre Nd3+ 4I9/2→4G5/2, 4G7/2 (W. T. Carnal) et al, J. Chem. Phys. 90, no. 7, 3443, 1989) in the spectrum range of 500-612 nm which corresponds to FWHM of the Ce3+ centre emission, causes a non-radiative energy transfer from the Ce3+ centre to the Nd3+ centre which results in the acceleration of the amplitude-dominant component 1 in the scintillation response which is depicted in FIG. 16, where the Y curve illustrates the scintillation response of the GGAG:Ce common material and the Z curve illustrates the scintillation response of the GGAG:Ce material co-doped with Nd as the first co-dopant. Both the materials were excited by gamma radiation of the photon energy 511 keV from the radioisotope 22Na. FIG. 16 illustrates with the Y curve the life time t3 of the GGAG:Ce crystal and with the Z curve the life time t2 of the GGAG:Ce, Nd crystal which is shortened to 54 ns in comparison with 91 ns of the GGAG:Ce material. Time t1 represents the start of the experiment. A double-sided polished scintillation disk with the diameter of 10 mm and thickness of 1 mm was manufactured from the Y0.985Tb0.01 Pr0.005AlO3 crystal, grown in Example 4. On surface it was provided with aluminium coating of the thickness of 50 nm. The disc was glued in the face of the all-sides polished cylinder from quartz glass. Positive potential+10 kV is lead to the aluminium coating. The positive potential attracts electrons to the scintillation disk and inside it, fast light flashes are created. The quartz cylinder leads light pulses from the scintillation disc to the fast optical detector. The assembly of the scintillation disc and quartz cylinder is placed in the electronic scanning microscope chamber and enables to detect the signal of secondary electrons with a time response of 5 ns/pxl. A plate with the diameter of 15 mm and thickness of 2 mm in epitaxial quality was polished from the undoped YAG single crystal. 20 μm thick layer of Gd2955Nd003Ce0015Ga3Al2O12 was applied onto the surface of the plate via the LPE (Liquid Phase Epitaxy) method. The scintillation disc was worked and except for one head surface, the epitaxial layer was polished off. A thin conductive ITO coating was coated onto the surface with the LPE layer. The disc was glued in the face of the all-sides polished cylinder from quartz glass. Positive potential+10 kV is lead to the aluminium coating. The positive potential attracts electrons to the scintillation disk and inside it, fast light flashes are created. The quartz cylinder leads light pulses from the scintillation disc to the fast optical detector. The assembly of the scintillation disc and quartz cylinder is placed in the electronic scanning microscope chamber and enables to detect the signal of secondary electrons. When compared to the same detector which contains a polished YAG:Ce disc, this detector has a higher light yield and operates with a shorter time response. The LYSO:Ce co-doped with Dy and GGAG:Ce co-doped with Nd single crystals were grown via the Czochralski method. Elements of 2×2×10 mm, polished from all sides, were prepared from each single crystal. From these elements the modules (matrix) were composed with the size of 8×8 elements (pixels) which were optically separated from each other. Both the matrices were connected together optically with the accuracy of minimally 0.1 mm, pixel to pixel. The whole element was inserted in a plastic casing and the crystal was optically connected with 64-pixel APD. The whole module was used in a positron scanner for tumour imaging in small animals, with a high special resolution and speed. A LuAG:Ce, Nd, Mg single crystal was grown via the Czochralski method according to Example 7 with a higher concentration of Nd in such a method that the response of the single crystal on the cerium centre was 20 ns. Fibres of the size 1×1×140 mm were prepared from the single crystal and all the surfaces were polished. A pixel detector was assembled from the fibres so that the fibres were interlaid with a tungsten sheet of 1 mm thickness. The detector contained 8×8 fibres. The detector was constructed in such a method that there were no optical leaks among the individual fibres. The pixels were insulated from each other with tungsten. The detector was connected at its end with a 64-pixel APD. The detector was used as an electromagnetic calorimeter to detect high energy particles originating in a proton-proton collider with the timing of 25 ns. Due to its short response this solution significantly increased the efficiency of particles detection. Scintillators with a shortened time of response according to the invention will be utilized in medical applications, working with ionizing radiation, such as positron emission tomography (PET) or CT, in scientific applications, such as in various calorimetric detectors, and in industry, particularly in detectors for the quality control of internal structures of mass produced products, such as chips, or e.g. during border controls.
	abstract	Methods and apparatus for synthesizing radiochemical compounds are provided. The methods include generating a quasi-neutral plasma jet, and directing the plasma jet onto a radionuclide precursor to provide one or more radionuclides. The radionuclides can be used to prepare radiolabeled compounds, such as radiolabeled biomarkers.
044252978	claims	1. A device for measuring local power generation within a fuel assembly of a nuclear reactor comprising: a gamma radiation absorbing body elongated along a longitudinal axis and made of heat conductive and electrically conductive material; elongated thermocouple means mounted within said body for establishing axially spaced differential temperature sensing junctions therein at each of a plurality of local measuring zones; coolant in external contact with said body throughout for establishing a uniform heat sink temperature extenally of said elongated body for producing radial heat flow paths from said junctions of said thermocouple means; reduced diameter portions of said elongated body at each of said local measuring zones for establishing thermal and electrical deviations in resistance of the elongated body producing a differential temperature signal across said junctions of said thermocouple means; and strengthening fins made of high thermally conductive material extending radially from said reduced diameter portion of said elongated body. a gamma radiation absorbing body elongated along a longitudinal axis having an external heat sink surface to which radial heat flow paths are established at axially spaced locations along the longitudinal axis by a reduced cross-sectional area portion thereof, and having a central bore within which is mounted a thermocouple having a cold junction at one of said spaced locations alligned with said reduced cross-sectional area portion and hot junction closely spaced therefrom; means for maintaining coolant in contact with said external heat sink surface; and strengthening fins made of high thermally conductive material extending radially from the reduced cross-sectional area portion. 2. A device for measuring local power generation within a nuclear reactor comprising: 3. In a method of calibrating a gamma sensor having an elongated monolithic body of electrically conductive material within which heat flow paths are established from axial spaced internal points between which a temperature differential is produced by a reduction in cross-sectional area of a portion of the body, the steps of: adding an electrically conductive filler to the reduced cross-sectional area portion of the body prior to conducting heating current through the body to render the voltage drop per length uniform; conducting electrical heating current longitudinally through the body for internal heating thereof; measuring the temperature differential across said axially spaced points; varying the heating current to determine the relationship between heat generated within the body and the measured temperature differential; and removing the filler from the body upon completion of calibration. 4. The method of claim 3 wherein said filler is made of a low melting temperature material to effect said removal thereof by melting.
043307086	description	DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention relates particularly to a rotationally symmetrical electrostatic charged particle lens having negligible spherical aberration over a very wide range of entrance angles, and to a method or process for making or producing such a lens. It is known that charged particles emanating from a point source or object on the axis of symmetry, and inclined at an angle .alpha. to the axis of a rotationally symmetrical lens, will form a circle having a radius .vertline.x.sub.s .vertline. in the image plane. For easier understanding, this is illustrated in FIG. 1, where the axis of symmetry is indicated at 101, and the point source or object at 103. Particles from this source move along a path such as 104 to the lens indicated schematically at 105, and thence, with changed direction, along the path 106 which intersects the axis at 107 and continues to intersect the image plane 108 at the point 109. The distance from the axis 101 to the point 109 is the radius .vertline.x.sub.s .vertline. of the circle above mentioned. Conventionally the sign of the angle .alpha. for the top ray is positive and the image dimension x.sub.s of this ray is negative, the reverse being true for the bottom ray illustrated in FIG. 1. This circle with radius .vertline.x.sub.s .vertline. is the result of spherical aberration in the lens. The size of the circle, and thus the degree or extent of spherical aberration, is usually expressed by the equation EQU x.sub.s =M[C.sub.3 .alpha..sup.3 +C.sub.5 .alpha..sup.5 +. . . ], (1) where M is the magnification and C with its various subscripts represents the spherical aberration coefficients. The form of the expansion is very general and applies to any lens. If the lens is apertured and the field is static (whether electric or magnetic) then C.sub.3 will always be positive. This means that any combination of charged particle lenses, whether they be electrostatic, magnetic, or a mixture of electrostatic and magnetic lenses, will have more spherical aberration than a single lens. This is very different from glass light optics, where a correction of spherical aberration can be accomplished by combination of lenses designed to produce negative and positive spherical aberration in amounts balancing each other. The resolving power of an electron microscope may be represented by the expression EQU R=C.sub.3.sup.1/4 .lambda..sup.3/4, (2) where R is the resolving power, C.sub.3 is the coefficient above mentioned, and .lambda. is the electron wavelength. Because of these relationships, the resolving power of an electron microscope is limited to about 2 Angstroms in the case of magnetostatic lenses and about 6 Angstroms for electrostatic lenses. The resolving power could be reduced in principle by using electrons of smaller wavelength and thus higher energy, but the contrast decreases rapidly with decreasing wavelength, thus making the above figures near the best possible. Another limitation caused by spherical aberration in electron lenses is a limitation of immense practical importance. This is the limitation resulting from the maximum current which can be used in a small probe. This current is represented by the formula ##EQU1## where I represents the current, d is the diameter of the probe, .beta. is the brightness of the source, and C.sub.3 is the spherical aberration coefficient of the final probe forming lens. The amount of time it takes to expose an electron resist in the field of electron beam lithography depends on the current. It is possible in principle to manufacture extremely small and complex integrated circuits with microprobes, but the extremely small current available in existing equipment makes this impractical. Various attempts over the past 30 years to correct or eliminate spherical aberration have included proposals for abandonment of rotational symmetry, introduction of space charge, the use of time varying fields, and covering the apertures with flat electron transparent conductors. In all cases either the aberrations introduced are much worse or the higher order terms such as C.sub.5, C.sub.7, etc., are found to be large. So far as known at present, no one has demonstrated an electron lens corrected for spherical aberration with optical properties clearly superior to a standard conventional electron lens. Part of the difficulty appears to result from computation problems. It has not been possible to predict the spherical aberration coefficients C.sub.3, C.sub.5, C.sub.7, etc., for a typical electron lens. This results from the inability to calculate electric or magnetic fields to the necessary accuracy. For example, in a microscope objective, the spherical aberration radius .vertline.x.sub.s .vertline. is about 2 Angstroms in size, while the lens is of millimeter dimensions. Clearly, a mistake of a few Angstroms will lead to an incorrect result. This implies an overall accuracy of better than one part in 10.sup.7. Calculating the electric or magnetic field to better than one percent is close to impossible. Approximations can be made for certain lenses that allow one to estimate C.sub.3 from incomplete knowledge of the field. Unfortunately, these types of lenses always have a positive value of C.sub.3. One aspect of the present invention deals with the solution of this computational problem. It was only after the computational problem was solved that it was possible to work on another aspect of the invention, the designing of an electron lens with complete or almost complete elimination of spherical aberration. In accordance with the invention it has been possible to produce electron lenses with spherical aberration radii .vertline.x.sub.s .vertline. that are as much as 100,000 times smaller than normal or conventional electron lenses, over a range of angles much larger than that usually used. For example, it is possible according to this invention to produce satisfactory lenses, well corrected for spherical aberration, having useful angles of 20 degrees, as compared with conventional electron lenses in which the useful angle is normally limited to about 0.5 degree, and with much greater spherical aberration than the lens of the present invention. The use of a lens according to the present invention as an electron microscope objective would give a resolving power below one Angstrom with greatly improved contrast and much less damage to the specimen being observed. If one of the improved lenses of the present invention is used in a probe forming machine, currents of as much as 1,000 times the currents now possible could be used. All corrected lenses developed according to the present invention have the following properties in common: 1. They are electrostatic and rotationally symmetrical. 2. The entrance and exit electrodes have inner edges which are smooth curves that are electrically continuous through the axis and are substantially particle transparent at and close to the axis. 3. The curved surfaces of the lenses must be precisely shaped to fit complicated surface equations to extreme accuracy. A technique for designing a lens according to the present invention will now be described. The electrostatic potential .PHI. in a charge free region satisfies Laplaces's equation EQU .tbd..sup.2 .phi.=0 . Rather than trying to satisfy this equation approximately for some particular set of boundary conditions, the preferred technique according to the present invention is to represent the potential as a linear combination of exact solutions of Laplace's equation and use boundary conditions given by the potential itself. A particular set of expansion coefficients is picked as an initial guess of the correct design. The electric field is confined along the symmetry axis between two equipotentials whose positions are now picked. An object position and an image position are picked and a trajectory of very small slope is calculated to find the image plane. If this does not coincide with the picked position, the lens potential is multiplied by some factor to bring them into coincidence. The magnification is calculated, and the spherical aberration x.sub.s is determined for a number of different angles. The "spherical aberration function" F.sub.i for the i.sup.th angle is defined by the equation ##EQU2## The sum of the squares of the spherical aberration function is designated by S, and is given by the equation ##EQU3## where NA is the total number of angles used. S is the function which is to be minimized as much as possible. This is done, according to the present invention, by making small changes in the potential expansion coefficients, in the position of the object or of the image, or a number of other possible variables, and then recalculating the value of S. From this information a new set of coefficients and variables is chosen that gives a smaller value of S. This process is repeated until no more improvement can be obtained by any reasonable amount of further calculation. Because one is looking for small changes in quantities that are already very small (x.sub.s) the accuracy requirements are severe. Overall calculation accuracy must usually be between one part in 10.sup.7 and one part in 10.sup.10. The electrostatic potential in a charge density free rotationally symmetrical region can be expressed as ##EQU4## In the above expression, .pi. and z are cylindrical coordinates, P.sub.n is the n.sup.th Legendre polynomial, and z.sub.in is the position of the i.sup.th multipole of (n+l).sup.th order. These functions are the known spherical zonal harmonics written in cylindrical rather than spherical coordinates. Any set of the coefficients {A.sub.n, B.sub.in, z.sub.in } will produce a potential that satisfies Laplace's equation. N.sub.n is the number of multipoles used of (n+l).sup.th order. The only constraint now required is that the set {z.sub.in } lie outside the lens region. The equations of the equipotentials that confine the field in the z direction are the following: EQU .phi.(.pi.,z)=.phi.(O,z.sub.L), (8) EQU .phi.(.pi.,z)=.phi.(O,z.sub.R). (9) In these equations, referring now to FIG. 2 of the drawings, z.sub.L and z.sub.R are the z intersection positions of the two equipotentials, as illustrated in FIG. 2. This view is intended as a schematic illustration to aid in quick understanding of the equations just mentioned, and the meaning of the other parts of FIG. 2 not specifically referred to herein will be obvious to those skilled in the art. Trajectory calculation will now be discussed. The relativistic trajectory equation for a point charge with no angular momentum is given by either of the following two equations: ##EQU5## In these equations, ##EQU6## and E represents the total energy expressed by ##EQU7## In the foregoing equation, m is the rest mass of the particle, q is the charge of the particle, c is the speed of light in vacuum, and v is the speed of the particle. Equation (10) is usually sufficient for calculating the trajectory. However, if the lens is a mirror, the path must be broken into sections along which either .pi. is a single valued function of z or z is a single valued function of .pi.. In the latter case, equation (11) is used. It is convenient to chose the units of electron volts for E and mc.sup.2. .PHI. will then be in volts, and q will be in electron charges. The quantities .pi. and z are dimensionless, by which is meant that they do not represent any particular linear dimension, but may be expressed in terms of centimeters, inches, or any convenient units of measurement. As will be noted further below, it is best to think of these quantities .pi. and z as merely "units" broadly, rather than any specific kind of measurement units, and the desired values can be given to these units at any convenient time. If the object position is in the region designated as region I in FIG. 2, and the velocity trajectory is inclined at an angle .alpha. to the z axis as seen in FIG. 2, then the particle will intersect the z.sub.L equipotential at the position .pi..sub.L , z.sub.L . This point of intersection is found by solving the equation EQU .phi.(.pi.(z),z)-.phi.(O,z.sub.L)=f(z)=0, (14) where EQU .pi.(z)=Tan (.alpha.)[z-z.sub.o ]. (15) These are solved by using "Newton's method." If the initial kinetic energy of the particle is E.sub.KI, then EQU E=E.sub.KI +q.phi.(O,z.sub.L). (16) Equation (10) can be numerically integrated using the initial conditions ##EQU8## Assuming that the lens is not a mirror, the particle will intersect the z.sub.R equipotential at the position .pi..sub.R , z.sub.R . This point is found by solving the equation EQU .phi.(.pi.(z),z)-.phi.(O,z.sub.R)=f(z)=0, (18) where .pi.(z) is given by the trajectory equation (10). "Newton's method" is again used. The trajectory equation for the trajectory in region III of FIG. 2 is given by the equation ##EQU9## Minimization procedure To determine the parameters for a lens with minimum spherical aberration, a trial set of potential expansion coefficients {A.sub.n, B.sub.in, z.sub.in } are picked; the z positions z.sub.O, z.sub.L, z.sub.R, and z.sub.I are picked, and the initial kinetic energy E.sub.KI are picked. A small angle trajectory is calculated. For this purpose, an angle of 10.sup.-10 radians is usually sufficient. The potential is adjusted to place the z intersection point at z.sub.I. A set of angles {.alpha..sub.i } is picked, and the spherical aberration at each angle is calculated from the equation ##EQU10## Equation (5) is used to obtain the spherical aberration function, and finally S is obtained from equation (6). S is a function of {A.sub.n, B.sub.in, z.sub.in }, z.sub.O, z.sub.L, z.sub.R, z.sub.I, and E.sub.KI. A.sub.o is not included in this set. Not all of these can be varied independently. It is necessary that at least one of the potential coefficients {A.sub.n, B.sub.in }, and two in the set z.sub.O, z.sub.L, z.sub.R, and z.sub.I be held fixed. Assuming that the set of parameters to be varied make up the set {B.sub.k }, then it is required that ##EQU11## where NV is the number of variables. This is solved by the technique of "damped least squares" which is a known technique used in the design of glass lens systems. Then the following set of linear equations must be solved for the {.DELTA.B.sub.l }. ##EQU12## .delta..sub.lk is the "Kronecker delta" and P is the "damping factor." P is chosen to yield the most rapid convergence. All of the partial derivatives in equation (22) must be calculated numerically. I have found that a "central difference" works well, but the size of the variation needed to give a derivative of a particular accuracy for each variable must be found by numerical experimentation. The new set of variables is given by {B.sub.k +.DELTA.B.sub.k } and the process is repeated until the equation (21) is sufficiently satisfied. The parameters for an immersion electron lens designed by the procedure explained above are given in Table I. The performance of this lens at a number of different angles is shown in Table II. The angles marked with an asterisk are those which were used in the minimization. Similarly, the parameters for a symmetrical unipotential electron lens are given in Table III, and the performance of that lens is shown in Table IV. Again in Table IV, the angles marked with asterisks are those used in the minimization. The use of the word "units" in the tables is a reminder that .pi. and z are dimensionless; that is, these units may represent centimeters, or inches, or any other units desired, so long as the same units are used throughout the tables for any one lens. All of the potential expansion coefficients not listed in Table I or Table III are equal to zero. TABLE I ______________________________________ (Immersion Electron Lens Parameters) z.sub.O = -2.02329139 "units" z.sub.L = -.5 "units" z.sub.I = 20 "units" z.sub.R = .5 "units" n A.sub.n in volts per ("unit").sup.n ______________________________________ 0 7.87648355 .times. 10.sup.3 1 2.24637513 .times. 10.sup.4 2 1.3422124 .times. 10.sup.4 3 2.4904 4 -2.4794 5 -1.6874 .times. 10.sup.1 6 -9.0515 7 5.6826 8 1.3035 .times. 10.sup.1 9 3.3451 .times. 10.sup.1 10 -9.318 .times. 10.sup.-2 11 -1.697 12 5.069 .times. 10.sup.-2 13 1.564 14 -2.784 15 -9.435 .times. 10.sup.-1 ______________________________________ E.sub.KI = 25 .times. 10.sup.3 electron volts .phi.(0, z.sub.L) = 0 volts .phi.(0, z.sub.R) = 7.51908605 .times. 10.sup.4 volts TABLE II ______________________________________ (Immersion Electron Lens Performance) M = -5.14194920 .alpha. in degrees F.sub.i in "units" ______________________________________ 5 .times. 10.sup.-3 -1.1 .times. 10.sup.-7 5 .times. 10.sup.-2 * -1.18 .times. 10.sup.-7 1 .times. 10.sup.-1 -1.18 .times. 10.sup.-7 5 .times. 10.sup.-1 * -1.23 .times. 10.sup.-7 1* -1.37 .times. 10.sup.-7 2 -1.91 .times. 10.sup.-7 3* -2.69 .times. 10.sup.-7 4 -3.56 .times. 10.sup.-7 5 -4.28 .times. 10.sup.-7 6* -4.62 .times. 10.sup.-7 7 -4.39 .times. 10.sup.-7 8 -3.49 .times. 10.sup.-7 10* -3.42 .times. 10.sup.-8 13* 9.16 .times. 10.sup.-8 14 -8.71 .times. 10.sup.-8 15* -2.91 .times. 10.sup.-7 17 -2.55 .times. 10.sup.-7 18* 3.36 .times. 10.sup.-8 19 1.62 .times. 10.sup.-7 20 -5.22 .times. 10.sup.-8 ______________________________________ TABLE III ______________________________________ (Symmetric Unipotential Election Lens Parameters) ______________________________________ z.sub.O = -.8 "units" z.sub.L = -.5 "units" z.sub.I = 10 "units" z.sub.R = .5 "units" n A.sub.n in volts per ("unit").sup.n ______________________________________ 0 -5.80210694 .times. 10.sup.1 2 3.80791093 .times. 10.sup.4 ______________________________________ z.sub.io in "units" B.sub.io in volts-"units" ______________________________________ .+-..5935 4.1656135 .times. 10.sup.2 .+-..604 -7.86681940 .times. 10.sup.2 .+-..6169 2.0430730 .times. 10.sup.3 .+-..6336 -2.25984 .times. 10.sup.3 .+-..6558 2.83345 .times. 10.sup.3 .+-..6870 -1.38254 .times. 10.sup.3 .+-..73375 2.13286 .times. 10.sup.3 .+-..8117 7.05492 .times. 10.sup.2 .+-..9675 5.52437 .times. 10.sup.3 .+-.1.435 6.4477 .times. 10.sup.3 ______________________________________ E.sub.KI = 70 .times. 10.sup.3 electron volts .phi.(0, z.sub.L) = 0 volts .phi.(0, z.sub.R) = 0 volts TABLE IV ______________________________________ (Symmetric Unipotential Electron Lens Performance) M = -9.18211043 .alpha. in degrees F.sub.i in "units" ______________________________________ 1 .times. 10.sup.-2 3.33 .times. 10.sup.-5 1* 1.093 .times. 10.sup.-5 2 -4.11 .times. 10.sup.-6 3* 5.04 .times. 10.sup.-6 4 1.760 .times. 10.sup.-5 5* 5.16 .times. 10.sup.-6 6 -1.203 .times. 10.sup.-5 7* -2.22 .times. 10.sup.-6 8 1.640 .times. 10.sup.-5 9* 9.12 .times. 10.sup.-6 10 -1.230 .times. 10.sup.-5 11* -1.186 .times. 10.sup.-5 12 1.000 .times. 10.sup.-5 13* 1.899 .times. 10.sup.-5 14 6.4 .times. 10.sup.-7 15* -1.931 .times. 10.sup.-5 16 -1.202 .times. 10.sup.-5 17* 1.226 .times. 10.sup.-5 18* 1.230 .times. 10.sup.-5 19* -2.170 .times. 10.sup.-5 20* 8.30 .times. 10.sup.-6 ______________________________________ Referring now to FIG. 3 of the drawings, this shows, in axial diametrical section, a corrected immersion lens according to a preferred embodiment of the invention. It comprises a lens cell or mount 1 and a spacer 2 both made of insulating material, and two electrodes 3 and 4 separated from each other at their edges by the spacer and held in position against the spacer by conventional retaining rings. These electrodes 3 and 4 are of electrically conducting material. The central region of each electrode, shown on an enlarged scale in FIGS. 4 and 5, is made of a very fine mesh metallic screen 5 preferably with a thin layer 6 of material which is electrically conducting and which is substantially transparent to passage of electrons, although this layer 6 may be omitted if desired. The electrode 4 and the screen 5 and the film 6, when such film is used, are all electrically continuous. It will be noted particularly that the central portion of the electrode, at and near the optical axis, is not flat or in a plane, but on the contrary is curved appreciably, this being a characteristic feature of the invention. The curvature is approximately but not exactly in the shape of a hyperbola. It is this shape which results in the reduction of spherical aberration in the lens. The exact shape of the curve is determined by the calculations above explained. FIG. 6 is an axial diametrical section through a mandrel useful in forming the electrode. The mandrel, shown at 61, is shaped to the desired curvature, and then the curved portion of the electrode 4 and its screen portion 5 are formed upon this mandrel. This will be further described below, in connection with FIG. 8. Of course a separate mandrel, with a somewhat different curvature, is used for forming the electrode 3 and its curved screen portion. Reference is now made to FIG. 7, illustrating a preferred form of electron lens. This lens has two electrodes 7 and 8 with curved central portions separated from each other and with their convex sides toward each other. In the space between these electrodes 7 and 8 there is another electrode 9 in the form of an annular ring. The electrodes are separated from each other by separators 10 and 11 of insulating material, held within the housing or cell 13 which may be of metal. A conducting connector 12 extends from the middle electrode 9 radially outward through an opening in the housing 13, to a suitable source of potential. The housing 13 and the electrodes 7 and 8 which normally are electrically connected to the housing 13 are at a different potential, preferably grounded. Reverting now to the immersion lens shown in FIG. 3, the shape of the interior surface of the electrodes (that is, the surfaces toward the spacer (2) is given by the equipotential equation (8) for electrode 4 and equation (9) for electrode 3, using the parameters listed in Table I, with the scale of the one "unit" representing one centimeter. It is only necessary to follow these equations for .pi. equal to or less than about 2 centimeters. This leads to a deviation in the actual performance from that of the mathematical model that is less than the deviation caused by machining inaccuracy. The best machining accuracy obtainable at present for cutting complicated rotationally symmetrical curves is with a computer operated lathe that utilizes laser interferometric techniques to determine the position of a diamond cutting tool. The machining accuracy is plus or minus 5000 Angstroms. A preferred method of forming an electrode to the desired shape according to the present invention will now be described. A mandrel, such as shown at 61 in FIG. 6, is formed with a surface corresponding in shape to the inner surface of the electrode to be produced. The mandrel may be produced by machining with a computer operated lathe as above mentioned. A central curved region of the mandrel, throughout an area as large as or larger than the area of the central screen shown especially in FIGS. 4 and 5 (the screen also being indicated by the thin line portions of FIGS. 3 and 7) is coated with a positive photoresist, as shown at 63 in FIG. 8. An evaporation mask is made by deforming a piece of fine mesh metal screen (500 or more openings per inch) of an area slightly larger than the screen area to be formed on the electrode as shown in FIGS. 3, 4, 5, and 7, this evaporation mask screen being shaped to correspond approximately with the curvature of the central region of the mandrel, which can be done by pressing the screen between a positive and a negative curved form that corresponds approximately to the shape of the central curved region of the mandrel. The curved screen is then placed on the mandrel over the photoresist, as indicated schematically at 65 in FIG. 8. Then a shield 67 with a circular central opening corresponding in diameter to the diameter of the desired final screen (as in FIG. 5, for example) is placed over the masking screen 65 as illustrated in FIG. 8, and serves to hold the masking screen 65 in place. This assembly is then placed in a vacuum chamber, and a thin film of aluminum is evaporated onto the photoresist 63 through the openings in the masking screen 65. This is continued until the aluminum film is deposed to a thickness of about 1 micron. The assembly is removed from the vacuum chamber, the shield 67 and masking screen 65 are removed from the photoresist, and the mandrel with the photoresist coating on it is exposed to a near parallel beam of light. The aluminum is now chemically removed, as for example by a sodium hydroxide solution. The photoresist is now developed in the conventional way, to yield columns projecting up from the central region of the mandrel, corresponding to the holes in the curved screen 65. Copper is now deposited into the region corresponding to the desired screen area and surrounding area of the electrode which is being constructed, by the well known technique of electroforming. Copper is prevented from becoming deposited on the rest of the mandrel by electrically insulating it from the plating bath. The plating will produce a screen structure in the central region and a solid structure elsewhere. The plating is halted when the thickness of the screen structure is approximately equal to the thickness of the columns of photoresist material. If this is not thick enough to provide adequate mechanical support (preferably about 25 microns in thickness) the mandrel may be coated with another layer of photoresist and the process may be repeated, taking care to line up the curved evaporation mask screen with the already deposited screen. This may be repeated as often as necessary to obtain a final copper screen thickness of any desired extent. The reason it may be necessary to do this deposit procedure more than once, is that the maximum thickness of the photoresist depends upon the spatial resolution needed to reproduce the screen, and on the particular brand of photoresist material which is used. It is sometimes useful to use a coarser evaporation screen mask for second and subsequent layers, to reduce the number of layers needed. When an adequate thickness in the center has been obtained, the central region is coated with an insulating material (more photoresist material works well for this purpose) to cover the screen area, and the electroforming is continued until the rest of the electrode is sufficiently thick, for example about 1 millimeter in thickness. The electrode is now stripped from the mandrel. If it is desired to have a layer of conducting material extend across the screen, such as shown at 6 in FIG. 4, this may be done by evaporating onto the inner surface of the electrode, in a vacuum chamber, a thin layer of electrical conducting material which is sufficiently transparent to the charged particles. Many conductive materials are suitable for this purpose, and the thickness to be deposited will depend on the material. Thicknesses of various materials which will permit sufficient passage of charged particles are well known in the art. As examples, carbon or aluminum or beryllium may be used, and for these materials, a thickness of 50 to 100 Angstroms is satisfactory for purposes of the present invention. The insulating material and the remaining photoresist are now dissolved from the central region, leaving the thin layer of deposited electrically conducting material which, as above stated, is transparent to the passage of the electrons or other charged particles. Referring now to the unipotential lens illustrated schematically in FIG. 7, the shape of the interior surfaces of the electrodes 7 and 8 (that is, the surfaces facing toward each other) is given by the equipotential equations (8) or (9), with the parameters listed in Table 3, and the scale of one "unit" being equal to 2 centimeters. Electrodes 7 and 8 are identical with each other, but are reversed so that their convex sides face each other as illustrated. The shape of the middle electrode 9 in FIG. 7 is given by the equipotential equation EQU .phi.(.pi., z)=-70.times.10.sup.3 volts. (23) The choice of this particular equipotential is for convenience, since the source of electrons would operate at the same voltage. It is only necessary to follow these equations for .pi..ltoreq.6 centimeters for the same reason as stated earlier for the immersion lens. The electrodes 7 and 8 may be constructed by the same technique above described for the construction of the electrodes 3 and 4. Using the manufacturing techniques according to the present invention for the electrodes, and with a machining accuracy within a tolerance of .+-.5000 Angstroms, the actual performance of these lenses will agree closely with the predicted performance stated in Tables II and IV. In addition to the prior art references given near the beginning of this specification, attention is called to the published article by Albert Septier on "The Struggle to Overcome Spherical Aberration in Electron Optics," appearing in "Advances in Optical and Electron Microscopy," volume I, edited by R. Barer and V. E. Cosslett, published by the Academic Press, London, England, in 1966. Attention is also called to the book "Focusing of Charged Particles," volume I, edited by Albert Septier, published by the Academic Press in 1967, which contains many of the equations which are used in the above disclosure of the present invention, as well as additional equations. In most or perhaps all cases, the various equations used in connection with the present invention must be solved by using a computer. In various places in the foregoing disclosure, an "electron lens" has been mentioned, and these words have been used as the title of the invention. This is merely for convenience and brevity of description. Actually, the lens of the present invention would be more appropriately called a "charged particle lens," since it is equally useful as a lens for all kinds of charged particles, such as protons and ions as well as electrons.
	claims	1. Apparatus for the containment, transportation, and storage of radioactive items, the apparatus comprising: a canister adapted for containment of a radioactive item, said canister comprising a body, an interior, and two ends; said interior adapted for the reception of said radioactive item; said body comprising integral sacrificial fenders located adjacent said ends and adapted to attenuate a shock administered to said canister, said integral sacrificial fenders comprised of extensions of said body. 2. The apparatus of claim 1 , wherein a portion of an exterior of said canister is adapted for attachment of a portion of said radioactive item. claim 1 3. The apparatus of claim 2 , wherein said exterior portion is disposed on a lid of said canister. claim 2 4. The apparatus of claim 1 , further comprising a secondary shield adapted for placement between portions of said radioactive item comprising high radioactivity and low radioactivity. claim 1 5. The apparatus of claim 1 , further comprising a stabilizer which is introduced in a gap between said interior of said canister and said radioactive item following reception of said radioactive item within said canister. claim 1 6. The apparatus of claim 1 , wherein said radioactive item comprises a nuclear reactor pressure vessel comprising a body, a head, and head-to-body attachments, and said canister is adapted for reception of said pressure vessel body with said pressure vessel head removed, and for attachment to said pressure vessel body by use of said head-to-body attachments. claim 1 7. The apparatus of claim 6 , wherein said attachment by means of said the head-to-body attachments comprises the sole attachment between said pressure vessel body and said canister. claim 6 8. The apparatus of claim 1 , wherein said body is substantially tubular. claim 1 9. A method of fabricating a containment vessel for use in removing a nuclear reactor pressure vessel from a reactor plant, the method comprising: fabricating a tubular body of sufficient cross-sectional dimension to accommodate a nuclear reactor pressure vessel body from a structural sheet material; enclosing an end of said tubular body; dividing said tubular body into a plurality of sections, said sections of suitable length for allowing a section comprising said enclosed end to be disposed in a position proximate an installation location for said pressure vessel, said pressure vessel body to be disposed within said closed section, a second section of said tubular body to be disposed adjacent said closed section, and said closed and second sections to be reattached. 10. The method of claim 9 , wherein the step of fabricating said tubular body includes providing a sufficient length for said body to comprise integral sacrificial fenders. claim 9
063317133	claims	1. An ion source assembly for an ion implanter comprising: a source sub assembly including, the ion source assembly further including a chamber having a chamber wall with an inner and outer surface, and being arranged to receive ions extracted from the ion source, the chamber wall defining an exit aperture to permit exiting of the said ions to the ion implanter; wherein the source sub assembly is movable relative to the chamber, the ion source assembly further comprising a constraining apparatus arranged to connect the chamber wall with the source sub assembly such that the source sub assembly is constrained to move along a fixed locus of points relative to the chamber to allow access to the inner wall thereof, the fixed locus of points being defined along a substantially horizontal plane. a source sub assembly including, the ion source assembly further including a chamber having a chamber wall with an inner and outer surface, and being arranged to receive ions extracted from the ion source, the chamber wall defining an exit aperture to permit exiting of the said ions to the ion implanter; wherein the source sub assembly is movable relative to the chamber, the ion source assembly further comprising a constraining apparatus arranged to connect the chamber wall with the source sub assembly such that the source sub assembly is constrained to move along a fixed locus of points relative to the chamber to allow access to the inner wall thereof, at least some of any loss in the potential energy of the source sub assembly during movement thereof being stored by the said constraining apparatus. (i) an ion source assembly including a source sub assembly having an ion source for generating ions to be implanted, an extraction electrode for extracting ions from the ion source, and a first electrical insulator arranged to support the extraction electrode relative to the ion source and to electrically insulate the said extraction electrode from the ion source; and a chamber having a chamber wall and being arranged to receive ions extracted from the ion source, the chamber wall defining an exit aperture to permit egress of the said ions as an ion beam; (ii) a substrate holder downstream of the ion source assembly, the ion beam being directed in use towards the said substrate holder, and the substrate holder being arranged to support at least one substrate to be implanted by the said ion beam; and (iii) constraining apparatus arranged to connect the chamber wall with the source sub assembly such that the source sub assembly is constrained to move along a fixed locus of points relative to the chamber to allow access to the inner wall thereof, the fixed locus of points being defined along a substantially horizontal plane, wherein the source sub assembly of the ion source assembly is movable relative to the chamber thereof. (i) an ion source assembly including a source sub assembly having an ion source for generating ions to be implanted, an extraction electrode for extracting ions from the ion source, and a first electrical insulator arranged to support the extraction electrode relative to the ion source and to electrically insulate the said extraction electrode from the ion source; and a chamber having a chamber wall and being arranged to receive ions extracted from the ion source, the chamber wall defining an exit aperture to permit egress of the said ions as an ion beam; (ii) a substrate holder downstream of the ion source assembly, the ion beam being directed in use towards the said substrate holder, and the substrate holder being arranged to support at least one substrate to be implanted by the said ion beam; and (iii) constraining apparatus arranged to connect the chamber wall with the source sub assembly such that the source sub assembly is constrained to move along a fixed locus of points relative to the chamber to allow access to the inner wall thereof, at least some of any loss in the potential energy of the source sub assembly during movement thereof being stored by the said constraining apparatus, wherein the source sub assembly of the ion source assembly is movable relative to the chamber thereof. 2. An ion source assembly as claimed in claim 1, wherein the source sub assembly is movable in use between a first position in which it is fixedly mounted upon the chamber walls and a second position in which it is movable relative to the chamber along the said fixed locus of points. 3. An ion source assembly as claimed in claim 2, wherein the constraining apparatus comprises a hinge mounted between the chamber and the source sub assembly. 4. An ion source assembly as claimed in claim 3, in which the hinge constrains the source sub assembly to move along the said fixed locus of points in the said substantially horizontal plane, whereby, in the said first position, the weight of the source sub assembly is borne across the chamber, and in the said second position, the weight of the source sub assembly is substantially all borne by the said hinge. 5. An ion source assembly as claimed in claim 1, further comprising extraction electrode support means arranged to support the said extraction electrode relative to the said first electrical insulator. 6. An ion source assembly as claimed in claim 5, wherein the ion source is generally elongate and has a first end along the axis of elongation, the said first end including an exit aperture permitting exiting of ions, wherein the extraction electrode support means is also elongate with a first end along the axis of elongation, the extraction electrode being mounted upon the said first end of the said extraction electrode support means, and wherein the axes of elongation of the extraction electrode support means and the ion source are generally collinear such that the extraction electrode is located generally parallel with and adjacent to the said exit aperture of the said first end of the ion source. 7. An ion source assembly as claimed in claim 6, in which the said first end of the said ion source constitutes a first electrode, and the said extraction electrode constitutes a second electrode, the assembly further comprising third and fourth electrodes mounted within the said chamber such that the second electrode is located between the first electrode and the third electrode, and the third electrode is located between the second electrode and the fourth electrode. 8. An ion source assembly as claimed in claim 1, further comprising a liner arranged to line at least a part of the said inner surface of the chamber wall. 9. An ion source assembly for an ion implanter comprising: 10. An ion source assembly as claimed in claim 9, wherein the source sub assembly is movable in use between a first position in which it is fixedly mounted upon the chamber walls and a second position in which it is movable relative to the chamber along the said fixed locus of points. 11. An ion source assembly as claimed in claim 10, wherein the constraining apparatus includes a hinge mounted between the chamber and the source sub assembly. 12. An ion source assembly as claimed in claim 9, further comprising extraction electrode support means arranged to support the said extraction electrode relative to the said first electrical insulator. 13. An ion source assembly as claimed in claim 12, wherein the ion source is generally elongate and has a first end along the axis of elongation, the said first end including an exit aperture permitting exiting of ions, wherein the extraction electrode support means is also elongate with a first end along the axis of elongation, the extraction electrode being mounted upon the said first end of the said extraction electrode support means, and wherein the axes of elongation of the extraction electrode support means and the ion source are generally collinear such that the extraction electrode is located generally parallel with and adjacent to the said exit aperture of the said first end of the ion source. 14. An ion source assembly as claimed in claim 13, in which the said first end of the said ion source constitutes a first electrode, and the said extraction electrode constitutes a second electrode, the assembly further comprising third and fourth electrodes mounted within the said chamber such that the second electrode is located between the first electrode and the third electrode, and the third electrode is located between the second electrode and the fourth electrode. 15. An ion source assembly as claimed in claim 9, further comprising a liner arranged to line at least a part of the said inner surface of the chamber wall. 16. An ion implanter comprising: 17. An ion implanter as claimed in claim 16, further comprising mass analysing means arranged between the said ion source assembly and the said substrate holder, the chamber of the said ion source assembly being fixedly mountable relative to the mass analysing means. 18. An ion implanter comprising: 19. An ion implanter as claimed in claim 18, further comprising mass analysing means arranged between the said ion source assembly and the said substrate holder, the chamber of the said ion source assembly being fixedly mountable relative to the mass analysing means.
046631127	claims	1. Method for determining the contents of a fuel rod containing fuel pellets of pure uranium dioxide and doped fuel pellets within a test range extending along the length of the fuel rod which comprises concentrically surrounding the fuel rod with a test coil and moving the test coil from the beginning to the end of the test range, measuring the impedance of the test core as a function of its position during movement, and feeding the test coil an a-c voltage with a frequency below 10 kHz to produce a measurement value in the region of a fuel pellet of pure uranium dioxide which clearly distinguishes from a measurement value in the region of a doped fuel pellet. 2. Method according to claim 1, wherein the measured values are recorded by a recorder as a function of the position of the test coil within the test range extending along the length of the fuel rod in the form of a measurement profile. 3. Method according to claim 2, wherein the measurement profile of the fuel rod to be tested is compared with a desired profile of a good fuel rod and, wherein as a result of this comparison, a switch is set for sorting the fuel rods subsequent to the measurement to separate fuel rods not having desirable characteristics.
048329002	claims	1. A test tool for a nuclear reactor vessel fluid level instrument system, comprising: means for providing continuously variable, active analog test signals to the instrumentation system, said means for providing comprising: potentiometers, connectable to the instrumentation system, for providing a variable resistance to the instrumentation system; switches, connectable to the instrumentation system, for returning a detection signal unmodified to the instrumentation system; and variable voltage means for providing a variable voltage to the instrumentation system; and means for verifying values of the test signals. a power supply; a resistance connected to said power supply; and a potentiometer connected to said resistance and connectable to the instrumentation system. compensation testing means for testing the temperature compensation system; pump status testing means for testing the pump status system; isolator testing means for testing the hydraulic isolator system; temperature testing means for testing the temperature hot system; pressure testing means for testing the differential pressure system; and wide range testing means for testing the pressure wide range system. a voltage power supply; and a variable resistance connected to said voltage power supply and connectable to the temperature hot system. at least three potentiometers connectable to the differential pressure system, each potentiometer having a wiper arm; and at least three resistors connected to the corresponding wiper arm and connectable to the differential pressure system. a voltage power supply; and a variable resistance connected to said voltage power supply and connectable to the pressure wide range system. first potentiometers, connectable to the temperature compensation subsystem, for providing substitute resistance temperature detector signals and used for testing the temperature compensation subsystem; pump status switches, connectable to the pump status subsystem, for providing substitute pump status signals and used for testing the pump status subsystem; isolator switches, connectable to the hydraulic isolator subsystem, for providing substitute isolator limit signals and used for testing the hydraulic isolator subsystem; a power supply; second potentiometers, connected to said power supply and connectable to the temperature hot subsystem, for providing substitute reactor coolant temperature signals and used for testing the temperature hot subsystem; third potentiometers, connectable to the differential pressure cell subsystem, providing substitute differential pressure cell signals and used for testing the differential pressure cell subsystem; and a wide range potentiometer, connected to the power supply and connectable to the pressure wide range subsystem, for providing a substitute wide range pressure signal and used for testing the pressure wide range subsystem. 2. A test tool as recited in claim 1, wherein said means for verifying comprises a meter, switchably connectable to either said variable resistance means or said variable voltage means, for measuring the variable resistance or variable voltage provided to the instrumentation system. 3. A test tool as recited in claim 2, wherein said variable voltage means comprises: 4. A test tool for a nuclear reactor vessel fluid level instrumentation system including a temperature compensation system, a pump status system, a hydraulic isolator system, a temperature hot system, a differential pressure system and a pressure wide range system, said test tool comprising: 5. A test tool as recited in claim 4, wherein said compensation testing means comprises means for providing a variable voltage drop to the temperature compensation system. 6. A test tool as recited in claim 5, wherein said means for providing comprises at least seven potentiometers connectable to the temperature compensation system. 7. A test tool as recited in claim 4, wherein said pump status testing means comprises means for transmitting a voltage therethrough. 8. A test tool as recited in claim 7, wherein said means for transmitting comprises at least four switches connectable to the pump status system. 9. A test tool as recited in claim 4, wherein said isolator testing means comprises means for transmitting a voltage therethrough. 10. A test tool as recited in claim 9, wherein said means for transmitting comprises at least three switches connectable to the hydraulic isolator system. 11. A test tool as recited in claim 4, wherein said temperature testing means comprises means for providing a variable voltage to said temperature hot system. 12. A test tool as recited in claim 11, wherein said means for providing comprises: 13. A test tool as recited in claim 12, wherein said variable resistance comprises at least two potentiometers connected to said power supply and connectable to the temperature hot system. 14. A test tool as recited in claim 4, wherein said pressure testing means comprises means for providing a variable current to the differential pressure system. 15. A test tool as recited in claim 14, wherein said means for providing comprises: 16. A test tool as recited in claim 14, wherein said wide range testing means comprises means for providing a variable voltage to the pressure wide range system. 17. A test tool as recited in claim 16, wherein said means for providing comprises: 18. A test tool for a pressurized water nuclear reactor vessel fluid level instrumentation system, the instrumentation system having a temperature compensation subsystem receiving resistance temperature detector signals, a pump status subsystem receiving pump status signals, a hydraulic isolator subsystem receiving isolator limit signals, a temperature hot subsystem receiving reactor coolant temperature signals, a differential pressure cell subsystem receiving differential pressure cell signals, and a pressure wide range subsystem receiving wide range pressure signals, said test tool comprising: 19. A test tool as recited in claim 18, further comprising a meter, switchably connectable to said first potentiometers, said second potentiometers, said third potentiometers and said wide range potentiometer, for verifying produced signal values.
	abstract	An imaging device includes: a first scintillator layer; an array of detector elements, wherein the array of detector elements comprises a first detector element; a second scintillator layer, wherein the array of detector elements is located between the first scintillator layer and the second scintillator layer; and a first neutral density filter located between the first scintillator layer and the first detector element and/or a second neutral density filter located between the second scintillator layer and the first detector element; wherein the first detector element is configured to generate a first electrical signal in response to light from the first scintillator layer, and to generate a second electrical signal in response to light from the second scintillator layer.
	claims	1. A method of mitigating plasma disruption, comprising:magnetically confining plasma in a plasma vessel;storing cooled pellets; andinjecting the cooled pellets into the plasma vessel at a known velocity from a location that has an absence of a magnetic field from the plasma vessel. 2. The method of claim 1,wherein the cooled pellets are cooled to less than or equal to 40 kelvin (K). 3. The method of claim 2, wherein the stored cooled pellets are cooled to 10 kelvin (K). 4. The method of claim 2, the pellets comprise solid pellets. 5. The method of claim 2, comprising using hollow shell pellets as the pellets. 6. The method of claim 5, wherein each hollow shell pellet encapsulates a payload. 7. The method of claim 6, wherein the payload comprises granules or a porous material. 8. The method of claim 6, wherein the payload comprises lithium, lithium deuteride, beryllium, beryllium deuteride, boron, boron nitride, or tungsten. 9. The method of claim 2, wherein each pellet includes lithium. 10. The method of claim 1, comprising using a hollow shell encapsulating a payload as the pellets. 11. The method of claim 10, wherein the hollow shell comprises lithium, lithium deuteride, beryllium, beryllium deuteride, or boron nitride. 12. The method of claim 10, wherein the payload comprises lithium, lithium deuteride, beryllium, beryllium deuteride, boron, boron nitride, or tungsten. 13. The method of claim 2, wherein each pellet includes beryllium.
051026139	description	MODE(S) FOR CARRYING OUT THE INVENTION Illustrated in FIGS. 1 and 2 is an exemplary nuclear reactor vessel 10 having a plurality of fine motion control rod drives 12 (FMCRD), only one of which is shown. In one exemplary embodiment, there are 205 FMCRDs 12 extending into the vessel 10 through the bottom thereof. The rod drive 12 includes a tubular housing 14 extending outwardly from the vessel 10 and conventionally secured thereto. The housing 14 is conventionally connected to a flange 16 which is disposed in flow communication with a scram line or conduit 18 which is conventionally selectively provided with high-pressure water 20 from a conventional high-pressure water accumulator 22 conventionally joined to the scram line 18. Conventionally disposed inside the housing 14 is a conventional ball screw or spindle 24, which in this exemplary embodiment includes conventional right-handed threads 26. The control rod drive 12 includes a longitudinal centerline axis 28, with the housing 12 and spindle 24 being disposed coaxially therewith. A conventional ball nut 30 is positioned over the spindle 24 and is conventionally restrained from rotating therewith so that as the spindle is rotated in a clockwise direction, the ball nut is translated in a downward direction away from the vessel 10, and when the spindle is rotated in a counterclockwise direction, the ball nut 30 is translated in an upward direction toward the vessel 10. A conventional hollow, elongate piston 32 is disposed coaxially with the spindle 24 and includes a conical base end 34 which rests on the ball nut 30, and a tip end 36 extending through a central aperture 38 in the outer end of the housing 14 into the vessel 10. The tip end 36 is conventionally coupled to a respective control rod 40 by a bayonet coupling, for example. The spindle 24 extends downwardly from the flange 16 through a conventional electrical motor 42 which selectively rotates the spindle 24 in either the clockwise direction or counterclockwise direction. The motor 42 is electrically connected to a conventional control 44 by a conventional electrical line 46a for selectively controlling operation of the motor 42. In accordance with the preferred embodiment of the present invention, the rod drive 12 further includes a radial brake assembly 48 joined to the motor 42 into which extends the spindle 24, also referred to as an input shaft 24. The brake assembly 48 is electrically joined to the control 44 by a conventional electrical line 46b for selectively braking and unbraking, or releasing, the input shaft 24. As illustrated in more particularity in FIG. 3, the brake assembly 48 includes an annular stationary base 50 conventionally fixedly secured to the motor 42, for example by bolts (not shown). The base 50 includes a central aperture 52 which receives a portion of the shaft 24 extending from the motor 42. Disposed coaxially with the shaft centerline axis 28 is an annular housing 54 of the brake assembly 48 which is conventionally fixedly secured to the base 50. The brake assembly 48 further includes an annular rotor disc 56 having a central aperture 58, as shown in more detail in FIG. 4, surrounding the shaft 24 and fixedly connected to the shaft 24 for rotation therewith by a conventional key 60. The rotor disc 56 has at least one and preferably a plurality of rotor teeth 62 extending circumferentially around the rotor disc 56 and extending radially outwardly from a perimeter 64 of the rotor disc 56. As illustrated in FIG. 5, each of the rotor teeth 62 includes a locking surface 66 which extends generally perpendicularly radially outwardly from the perimeter 64 and parallel to the centerline axis 28. Each rotor tooth 62 further includes an inclined surface 68 extending from the locking surface 66, and forming a peak 70 therewith, to the perimeter 64 in a circumferential direction relative to the centerline axis 28 and the perimeter 64. A nonrotating brake member 72 as shown in FIGS. 3 and 4 is disposed adjacent to the rotor disc perimeter 64 and includes at least one braking tooth 74. In the preferred embodiment of the present invention illustrated in FIGS. 3 and 4, first and second brake members, designated 72 and 72b, are circumferentially spaced from each other at about 180.degree. apart. The two brake members 72, 72b are preferably used for redundancy and for halving the braking force required from each of the brake members 72. The two brake members 72, 72b are preferably identical and, therefore, the description below with respect to the first brake member 72 applies also to the second brake member 72b. As illustrated in FIG. 6, the brake member 72 further includes an arcuate base 76 having an inner arc 78, from which the braking tooth 74 extends radially inwardly therefrom relative to the centerline axis 28. The braking tooth 74 further includes a locking surface 80 extending radially inwardly from the brake member inner arc 78, and an inclined surface 82 extending therefrom to form a peak 84, and also extending in a circumferential direction to the inner arc 78. As illustrated in FIGS. 5-7, the rotor tooth 62 is preferably complementary to the braking tooth 74, i.e., having mirror image configurations so that the rotor tooth locking surface 66 abuts the braking tooth locking surface 80, and the rotor tooth inclined surface 68 is disposed adjacent and parallel to the braking tooth inclined surface 82 in a brake member deployed position 72d shown in solid line in FIG. 7. In a preferred embodiment of the invention, the brake member base 76 includes a plurality of circumferentially spaced ones of the braking teeth 74, three being shown for example, with adjacent ones of the braking teeth 74 being joined together at generally V-shaped valleys 86 defined at the intersections of the inclined surfaces 82 and locking surfaces 80. Similarly, adjacent ones of the rotor teeth 62 are joined together at generally V-shaped valleys 88 defined at the intersections of the inclined surfaces 68 and the locking surfaces 66 as shown in FIG. 5. As shown in FIG. 6, the peaks 70 and 84 are received in the respective valleys 86 and 88 in the brake member deployed position 72d. As illustrated in FIGS. 4 and 7, means 90 are provided for selectively positioning the brake member 72 in the deployed position 72d, shown in dashed line in FIG. 4, abutting the rotor disc perimeter 64 for allowing the braking tooth locking surface 80 to contact the rotor tooth locking surface 66 for preventing rotation of the rotor disc 56 and the shaft 24 in the clockwise, or first, direction. The positioning means 90 are also effective for positioning the brake member 72 in a retracted position 72r, shown in solid line in FIG. 4 and in dashed line in FIG. 7, spaced radially away from the rotor disc 56 for allowing the rotor disc 56 and the shaft 24 to rotate without restraint from the brake member 72. Identical positioning means 90 are used for positioning both the first and second brake members 72, 72b in the deployed and retracted positions, and therefore, the description of the positioning means 90 provided hereinbelow applies to both brake members. Referring again to FIG. 4, the brake assembly 48 further includes an annular frame 92 fixedly joined to the housing 54 by a plurality of circumferentially spaced webs 94 preferably formed integrally therewith, by casting for example. As shown in more particularity in FIG. 7, the frame 92 includes a radially extending guide hole 96. The brake member 72 further includes an elongate, hollow plunger 98 which extends radially outwardly relatively to the centerline axis 28 from the base 76 in a direction opposite to that of the braking teeth 74. The plunger 98 is slidably joined to the frame 92 through the guide hole 96. The base 76 is sized preferably larger than the plunger 98 so that the plunger 98 may slide through the guide hole 96 in a radial direction until the base 76 contacts the frame 92 which thereby prevents further radial movement. The frame 92 may include a recess 100 having a configuration complementary to that of the base 76 for storing therein the base 76 when the brake member 72 is disposed in its retracted position 72r as illustrated in dashed line in FIG. 7. In a preferred embodiment, the positioning means 90 includes a conventional tubular solenoid 102 fixedly joined to the frame 92, by bolts for example, as shown in FIG. 8. The solenoid 102 includes a central bore 104 disposed around the plunger 98. A compression spring 106 is disposed in the plunger 98 within the solenoid central bore 104 and is initially compressed between the base 76 and a retaining plate 108 suitably secured to the solenoid 102. The compression spring 106 is initially compressed for forcing the brake member 72 against the rotor disc 56 to engage the braking teeth 74 against the rotor teeth 62 in the brake member deployed position 72d when the solenoid 102 is preferably deenergized. As shown in FIG. 7, with the brake member 72 engaging the rotor disc 56, the braking teeth locking surfaces 80 abut against the rotor teeth locking surfaces 66 preventing the rotor disc 56 and the shaft 24 from rotating in the clockwise direction. As described above, the clockwise direction is defined as that direction of rotation of the shaft 24 which will cause the ball nut 30 and the control rod 40 to be withdrawn from the vessel 10 as illustrated in FIG. 2 since the spindle 24 has right-handed threads 26. The counterclockwise, second, direction, opposite to that of the first direction is that direction of rotation of the shaft 24 which will cause the ball nut 30 and the control rod 40 to be inserted relative to the vessel 10. When the solenoid 102 is predeterminedly energized by the control 44 through the electrical line 46b conventionally connected thereto, the solenoid 102 conventionally electromagnetically draws the plunger 98, which acts as an armature, further into the solenoid bore 104 and further compresses the spring 106 for positioning the brake member 72 in the retracted position 72r. Accordingly, when the solenoid 102 is energized and deenergized, the plunger 98 slides in the guide hole 96 to the retracted position 72r and the deployed position 72d, respectively, for disengaging or engaging the rotor teeth 62 and the braking teeth 74, respectively. When the brake member 72 is held in its retracted position by the energized solenoid 102, the rotor disc 56 and the shaft 24 may be rotated without restraint from the brake assembly 48 in a conventional manner by the motor 42. When the brake member 72 is positioned in its deployed position 72d engaging the rotor disc 56 upon deenergization of the solenoid 102, clockwise rotation of the shaft 24 is positively prevented. However, the positioning mean 90 also resiliently supports the braking teeth 74 since the brake member base 76 is supported on the compression spring 106. Accordingly, when it is desired to activate the motor 42 for rotating the shaft 24 in a counterclockwise direction for further inserting the control rod 40 into the vessel 10, this may be accomplished even with the brake member 72 engaged which adds to the safety features of the present invention. In this situation, counterclockwise rotation of the shaft 24 will cause the rotor teeth inclined surfaces 68 to displace radially outwardly the braking teeth inclined surfaces 82, and thereby the entire brake member 72, by a camming action until the rotor tooth peak 70 passes by the braking tooth peak 84 in a ratcheting fashion to intermittently free the rotor teeth locking surfaces 66 from the braking teeth locking surfaces 80. This allows the motor 42 to rotate the shaft 24 in the counterclockwise direction even though the brake member 72 is in its deployed position. FIG. 7 illustrates the brake member 72 in its deployed position 72d, its fully retracted position 72r, and in its intermediate position 72i shown in dashed line therebetween. The intermediate position 72i illustrates the maximum radial displacement of the brake member 72 from its deployed position 72d due to the counterclockwise movement of the shaft 24 just as one rotor tooth peak 70 passes an adjacent braking tooth peak 84, after which, the peak 84 will then be returned by the spring 106 adjacent to the next succeeding rotor tooth valley 88. In the preferred embodiment of the present invention as illustrated in FIG. 8, the plunger 98 and guide hole 96 preferably have complementary, square axial cross-sections. These square cross-sections allow the plunger 98 to slide radially in the guide hole 96 but prevent any rotational movement thereof which is preferred for maintaining the circumferential alignment of the brake member 72 relative to the rotor disc perimeter 64. Other cross-sectional shapes could also be used including circular so long as effective means are provided for preventing rotation of the brake member 72 for maintaining alignment of the braking teeth 74 with the rotor teeth 62. Also in the preferred embodiment, the solenoid 102, including its central bore 104, is square in axial cross-section for more closely accommodating the square plunger 98. Of course, circular solenoids may alternatively be used. As illustrated in FIG. 7, the plunger 98 includes a longitudinal centerline axis 110 which extends radially outwardly from the shaft centerline axis 28 so that the plunger 98 is disposed perpendicularly to the shaft centerline axis 28. The rotor and braking teeth locking surfaces 66, 80 preferably extend radially outwardly relative to the shaft centerline axis 28 for providing an increased amount of restraining torque from the braking teeth 74 against the rotor teeth 62. Since the brake member 72 includes a plurality, and in this example three, braking teeth 74, it is preferred that the rotor teeth locking and inclined surfaces 66, 68 and the braking teeth locking and inclined surfaces 80, 82 form respective obtuse angles A therebetween. The obtuse angle A is preferably generally close in value to 90.degree., and in an alternate embodiment of the present invention may even be 90.degree., to ensure that all of the plurality of braking teeth 74 on the brake member 72 engage respective rotor teeth 62 on the rotor disc 56 when the brake member 72 is deployed. In the simplest form of the present invention, only one of the two brake members 72, 72b is required, and only a single braking tooth 74 is required. However, for increased redundancy and for decreasing reaction forces, a plurality of both braking teeth 74 and rotor teeth 62, and two brake members 72, 72b are preferred. The particular configuration of the respective rotor teeth 62 and braking teeth 74 may be determined for each specific design and is a function of the total number of teeth provided, the spacing therebetween, and the angle of the plunger 98 relative to the rotor disc 56. Alternate configurations of the rotor teeth 62 and the braking teeth 74 include for example symmetrical, isosceles-type teeth, as well as teeth 62, 74 wherein the angle A is less than 90.degree.. In all designs, however, it is preferred that effective braking occur in the first, clockwise direction for preventing rotation due to the backflow occurrence, for example, while allowing rotation in the second, counterclockwise rotation by intermittently displacing the braking teeth 74 by the rotor teeth 62. Accordingly, the brake assembly 48, in accordance with the preferred embodiment, provides complementary sawtooth profile rotor and braking teeth 62 and 74 which are effective for locking the shaft 24 and preventing rotation in preferably one direction, e.g., clockwise direction only, when the solenoid 102 is deenergized. This positive locking of the shaft 24 prevents rotation of the shaft 24 in the clockwise direction for preventing inadvertent withdrawal of the control rod 40 under the backflow occurrence, for example. When the solenoid 102 is energized, the brake member 72 is retracted from the rotor disc 56 allowing the shaft 24 to rotate, and then the motor 42 may be conventionally operated for predeterminedly either inserting or withdrawing the control rod 40. The brake assembly 48 as described above thus provides a positive lock of the shaft 24 to prevent unintentional ejection travel of the control rod 40 from the vessel 10 while allowing for both insertion of the control rod 40 while the brake member 72 is disposed in the deployed position 72d, and allowing for relatively simple testing of the brake assembly 48. More specifically, the brake assembly 48 may be simply tested by de-energizing the solenoid 102 for positioning the brake member 72 in the deployed position 72d and then energizing the motor 42 for clockwise rotation to allow the rotor teeth locking surfaces 66 to abut against, and be circumferentially restrained by the braking teeth locking surfaces 80 which prevents clockwise rotation of the shaft 24. Since the motor 42 will be unable to rotate the shaft 24 relative to the brake member 72 in the clockwise direction, the motor 42 will stall, which may be conventionally observed by the control 44 for indicating the effective operation of the brake assembly 48. If the brake assembly 48 is unable to prevent the clockwise rotation of the shaft 24 during testing, the control 44 can conventionally provide a suitable indication thereof, which may then result in manual inspection of the brake assembly 48 for correcting any problem that might exist. While there have been described herein what are considered to be preferred embodiments of the present invention, other modifications of the invention shall be apparent to those skilled in the art from the teachings herein, and it is, therefore, desired to be secured in the appended claims all such modifications as fall within the true spirit and scope of the invention.
	claims	1. A passive cooling and depressurization system for a pressurized water nuclear plant having a reactor pressure vessel for containing a reactor core cooled by primary coolant, a steam generator connected to the reactor pressure vessel by a hot leg pipe and a cold leg pipe, and a containment vessel containing the reactor pressure vessel, the steam generator, the hot leg pipe and the cold leg pipe, the passive cooling and depressurization system comprising:a pressurizer connected to the hot leg pipe by a riser pipe for pressurizing an inside of a reactor pressure boundary where the primary coolant flows;a cooling water pool;a heat exchanger installed in the cooling water pool including an upper header, a lower header and a heat exchanger tube;a steam supply piping extending from a gas phase of the pressurizer to the upper header of the heat exchanger;a steam supply valve equipped on the steam supply piping;a coolant return pipe extending from the heat exchanger to a liquid phase of the reactor pressure boundary; andan outlet valve equipped on the coolant return pipe,wherein the heat exchanger exchanges heat between water stored in the cooling water pool and steam supplied through the steam supply piping. 2. The passive cooling and depressurization system of claim 1, wherein the steam supply valve is a steam regulator valve that is configured to regulate a flow rate at steam through the steam supply valve. 3. The passive cooling and depressurization system of claim 1 further comprising a depressurizing valve equipped on the steam supply piping in parallel with the steam supply valve, wherein the steam supply valve allows steam of a quantity equivalent to a quantity of steam generated by decay heat of the reactor core to pass through the steam supply valve. 4. The passive cooling and depressurization system of claim 1, wherein at least part of the heat exchanger is arranged above a liquid level in the pressurizer. 5. The passive cooling and depressurization system of claim 1, wherein cooling water pool is an in-containment refueling water storage tank. 6. The passive cooling and depressurization system of claim 1, wherein the cooling water pool is arranged outside the containment vessel and a gas phase of the cooling water pool communicates with air external to the containment vessel. 7. The passive cooling and depressurization system of claim 6, wherein the cooling water pool communicates with a passive containment cooling system pool. 8. The passive cooling and depressurization system of claim 1, wherein the containment vessel is partitioned into a first space and a second space containing the reactor pressure boundary by a diaphragm, the cooling water pool is arranged in the first space, and a gas phase of the cooling water pool communicates with an external air. 9. The passive cooling and depressurization system of claim 8, wherein the cooling water pool communicates with a passive containment, cooling system pool. 10. The passive cooling and depressurization system of claim 1, further comprising a vent pipe connected to the heat exchanger for venting noncondensable gases into the containment vessel and a vent valve being equipped on the vent pipe. 11. The passive cooling and depressurization system of claim 10, wherein an end of the vent pipe opposite to an end connected to the heat exchanger is open in a pressure suppression pool water stored in a pressure suppression chamber. 12. A pressurized water nuclear plant comprising:a reactor core cooled by primary coolant;a reactor pressure vessel containing the reactor core;a steam generator connected to the reactor pressure vessel by a hot leg pipe and a cold leg pipe;a pressurizer of the pressurized water nuclear plant connected to the hot leg pipe by a riser pipe for pressurizing inside of a reactor pressure boundary where the primary coolant flows;a containment vessel containing a reactor pressure vessel, the steam generator, the hot leg pipe, the cold leg pipe, the riser pipe and the pressurizer;a cooling water pool;a heat exchanger installed in the cooling water pool, the heat exchanger including an upper header, a lower header and a heat exchanger tube;a steam supply piping extending from a gas phase of the pressurizer to the upper header of the heat exchanger;a steam supply valve equipped on the steam supply piping;a coolant return pipe extending from the heat exchanger to a liquid phase of the reactor pressure boundary; andan outlet valve equipped on the coolant return pipe,wherein the heat exchanger exchanges heat between water stored in the cooling water pool and steam supplied through the steam supply piping.
050874080	claims	1. A nuclear reactor facility comprising a primary containment vessel, a reactor pressure vessel installed in the primary containment vessel and accommodating a reactor core in a lower part thereof, a vertical cylindrical wall disposed in a lower part of the primary containment vessel around and spaced from the reactor pressure vessel so as to delimit an annular space therebetween, the vertical cylindrical wall having an upper end disposed at a position higher than an upper end of the reactor core, a diaphragm extending substantially horizontally between the upper end of the vertical cylindrical wall and an inner wall of the primary containment vessel for cooperating with the vertical cylindrical wall to separate a space in the primary containment vessel around the reactor pressure vessel into a pressure suppression chamber and a drywell which includes the annular space, the pressure suppression chamber accommodating therein a pool of liquid coolant wherein a level of the liquid coolant of the pool is higher than the upper end of the reactor core, the vertical cylindrical wall having a plurality of vent passages having an upper part at the upper end of the vertical cylindrical wall and exposed to the drywell and a lower part exposed to the pool of the liquid coolant in the pressure suppression chamber, a submergence line extending from the pressure suppression chamber to the reactor pressure vessel at a position above the upper end of the reactor core and having at least one valve therein for cooperating with the submergence line to introduce the liquid coolant from the pool of the liquid coolant in the pressure suppression chamber to the reactor pressure vessel when the valve is opened for cooling of the reactor core, and a channel member for enabling liquid coolant to flow from the annular space between the vertical cylindrical wall and the reactor pressure vessel in the drywell into the pressure suppression chamber when liquid coolant fills the annular space, the channel member having one end opened at an upper part of the vertical cylindrical wall to the annular space between the vertical cylindrical wall and the reactor pressure vessel and another end exposed to the pool of the liquid coolant in the pressure suppression chamber, the channel member having the one opened end thereof positioned higher than the level of the liquid coolant of the pool in the pressure suppression chamber. 2. A nuclear reactor facility according to claim 1, further comprising a gas discharge pipe extending outside of the primary containment vessel from a gaseous phase portion in the pressure suppression chamber which is above the level of the liquid coolant of the pool, and at least one valve being disposed in the gas discharge pipe.
	claims	1. An EUV projection optical unit configured to image an object field in an image field, the EUV projection optical unit comprising:a plurality of mirrors configured to guide imaging light from the object field to the image field,wherein:the EUV projection optical unit has an image-side numerical aperture of at least 0.4;an overall reflectivity of the EUV projection optical unit is a product of the reflectivity of each of the plurality of mirrors;the overall reflectivity of the EUV projection optical unit is greater than 7%; andthe EUV projection optical unit has a total of eight mirrors. 2. The EUV projection optical unit of claim 1, wherein:the plurality of mirrors is configured to guide the imaging light from the object field to the image field along a beam path;the plurality of mirrors comprises first and second mirrors;the second mirror is directly behind the first mirror in the beam path; andfor each of the first and second mirrors, an angle of incidence of the imaging light with the mirror is greater than 60°. 3. The EUV projection optical unit of claim 2, wherein, among the plurality of mirrors, only the first and second mirrors have an angle of incidence of the imaging light with the mirror is greater than 60°. 4. The EUV projection optical unit of claim 2, wherein:the plurality of mirrors further comprises third and fourth mirrors; andamong the plurality of mirrors, only the first, second, third and fourth mirrors have an angle of incidence of the imaging light with the mirror is greater than 60°. 5. The EUV projection optical unit of claim 4, wherein:the second mirror is directly behind the first mirror in the beam path; andthe fourth mirror is directly behind the third mirror in the beam path. 6. The EUV projection optical unit of claim 1, wherein:the object field is in an object plane of the EUV projection optical unit;the image field is in an image plane of the EUV projection optical unit; andan angle between the object plane and the image plane is different from 0°. 7. The EUV projection optical unit of claim 1, wherein the EUV projection optical unit comprises at least two mirrors configured to have an angle of incidence with the imaging light that is less than 45°. 8. The EUV projection optical unit of claim 1, wherein the EUV projection optical unit comprises at least four mirrors configured to have an angle of incidence with the imaging light that is less than 45°. 9. The EUV projection optical unit of claim 1, wherein the overall reflectivity of the EUV projection optical unit is greater than 9%. 10. The EUV projection optical unit of claim 1, wherein the EUV projection optical unit has an object-side chief ray angle for a field center point that is less than 7°. 11. The EUV projection optical unit of claim 10, wherein the image field has an extent of more than 13 mm along a field dimension. 12. The EUV projection optical unit of claim 1, wherein the image field has an extent of more than 13 mm along a field dimension. 13. The EUV projection optical unit of claim 12, wherein the extent of the image field is more than 20 mm along the field dimension. 14. The EUV projection optical unit of claim 1, wherein the image-side numerical aperture is at least 0.5. 15. The EUV projection optical unit of claim 1, wherein at least one of the mirrors has a free-form reflection surface. 16. An optical system, comprising:an EUV projection optical unit according to claim 1; andan illumination optical unit configured to illuminate the object field with illumination and imaging light. 17. The optical system of claim 16, further comprising an EUV light source. 18. The optical system of claim 16, wherein the optical system is an EUV projection exposure apparatus. 19. The optical system of claim 18, further comprising a reticle holder configured to hold a reticle, wherein the reticle holder is configured to move the reticle in a scanning direction, and an imaging scale of the EUV projection optical unit in the scanning direction is greater than in a direction perpendicular thereto. 20. A method of using an EUV projection exposure apparatus comprising an EUV projection optical unit and an illumination optical unit, the method comprising:using the illumination optical unit to illuminate an object plane; andusing the EUV projection optical unit to project the illuminated object plane onto a field plane,wherein the EUV projection optical unit comprises EUV projection optical unit according to claim 1.
059268573	abstract	An armor with rollers is provided that enables a user to move in all positions by rolling on a hard and smooth surface while constantly varying his bearing points on the ground. The armor includes a pair of gauntlets extending from beyond the user's hand to the user's elbow and having rollers at both ends thereof. The armor also includes a pair of rigid leg pads having rollers near the user's knees.
	description	The present U.S. Patent Application having at least one common inventor as U.S. patent application Ser. No. 10/786,318 entitled “System and Method for Fault Contactor Detection”, is now U.S. Pat. No. 7,130,170, and U.S. patent application Ser. No. 10/786,320 entitled “System and Method for Configuring A Soft Starter”, (2004P02542US), and being filed with the U.S. Patent and Trademark Office concurrently on Feb. 25, 2004, the entirety of each is incorporated herein by reference. This invention relates to a motor controller, such as a soft starter, and, more particularly, to a system and method for electrical system monitoring and diagnosis using a motor controller. Solid state starters/controllers have found widespread use for controlling application of power to an AC induction motor. The conventional starter/controller, referred to hereinafter as simply a controller, uses solid state switches for controlling application of AC line voltage to the motor. The switches may be thyristors such as silicon controlled rectifiers (SCRs) or triacs. Conventional controllers include a housing enclosing the solid state switches and a control circuit for controlling operation of the solid state switches: For configuring controller operation the motor controller may include push button switches for setting parameter functions and ranges. Indicator lights, such as LEDs, may be used for status indication. While such a user interface may be adequate for configuring the motor controller and for monitoring, the user interface may not be considered user friendly to some end users. Particularly, selecting parameters to monitor may be time consuming and allows only a single parameter to be monitored. One application for such a controller is as an elevator starter. The motor controller may be used to drive a pump for an hydraulic elevator. Each time movement of an elevator car is commanded, then the motor controller must start the elevator motor until it reaches operating speed and then operate in a run mode. Such a motor controller may only be used for the up direction as gravity may be used for the down direction. One type of elevator starter, referred to as a soft starter, changes the on time of the solid state switches to control voltage and to ramp up motor current with a fixed connection. Occasionally, an elevator system may experience some problem with the power system, causing downtime for the elevator. The elevator service technician may go to the site but not see any problem at that specific time. To try to solve the problem, the technician may need to buy or rent expensive monitoring equipment to record power system values to analyze the problem. The present invention is directed to improvements in monitoring and diagnosis of an electrical system. In accordance with the invention, there is provided a system and method for providing electrical system monitoring and diagnosis. Broadly, there is disclosed herein in accordance with one aspect of the invention a method of providing electrical system monitoring and diagnosis, comprising providing a motor controller including solid state switches for controlling the application of power to the motor, and a control circuit for controlling operation of the solid state switches and for measuring electrical power system characteristics relating to operation of the solid state switches; providing an external monitoring and diagnostic device; establishing communications between the control circuit and the external monitoring and diagnostic device; and periodically transferring parameters of the measured electrical power system characteristics from the control circuit to the external monitoring and diagnostic device to monitor electrical power system characteristics in real time. It is a feature of the invention that providing a motor controller comprises providing a control circuit including a programmed processor for commanding operation of the solid state switches and a memory connected to the programmed processor for storing parameters of the measured electrical power system characteristics. It is another feature of the invention that transferring parameters of the measured electrical power system characteristics comprises reading the stored parameters of the measured electrical power system characteristics from the memory. It is another feature of the invention that providing an external monitoring and diagnostic device comprises providing a computer or personal digital assistant having a memory for storing the transferred parameters. It is still another feature of the invention to print a list of the transferred parameters of the measured electrical power system characteristics. It is still a further feature of the invention that the parameters are transferred at select time intervals. It is yet an additional feature of the invention that the control circuit measures line voltage, motor voltage and motor current. It is still another feature of the invention that establishing communications between the control circuit and the external monitoring and diagnostic device comprises providing an infrared communication path or a wired communication path between the control circuit and the external monitoring and diagnostic device. There is disclosed in accordance with another aspect of the invention a motor controller system for monitoring and diagnosing electrical power system characteristics comprising a motor controller including solid state switches for controlling application of power to a motor and a control circuit for controlling operation of the solid state switches and for measuring electrical power system characteristics relating to operation of the solid state switches. An external monitoring and diagnostic device includes a memory for storing parameters of the measured electrical power system characteristics and an interface for communication with the motor controller. Means are operatively associated with the control circuit and the external monitoring and diagnostic device for transferring parameters of the measured electrical power system characteristics from the control circuit to the external monitoring and diagnostic device to monitor electrical power system characteristics in real time. There is disclosed in accordance with yet another aspect of the invention a soft starter system for monitoring and diagnosing electrical power system characteristics comprising a motor controller including solid state switches for controlling application of power to a motor. A control circuit controls operation of the solid state switches. The control circuit comprises a programmed processor for commanding operation of the solid state switches and for measuring electrical power system characteristics relating to operation of the solid state switches. A memory is connected to the programmed processor storing parameters of the measured electrical power system characteristics. An external monitoring and diagnostic device includes a memory for storing parameters of the measured electrical power system characteristics and an interface for communication with the motor controller. A monitoring and diagnostic program is operatively implemented in the external monitoring and diagnostic device for transferring parameters of the measured electrical power system characteristics from the control circuit to the external monitoring and diagnostic device to monitor electrical power system characteristics in real time. Further features and advantages of the invention will be readily apparent from the specification and from the drawings. Referring initially to FIG. 1, a solid state motor starter/controller 20, referred to hereinafter as simply a controller, in accordance with the invention is illustrated. One application for the controller 20 is as an elevator starter. The motor controller 20 may be used to drive a pump for an hydraulic elevator. Each time movement of an elevator car is commanded, then the motor controller 20 must start the elevator motor until it reaches operating speed and then operate in a run mode. Such a motor controller 20 may only be used for the up direction as gravity may be used for the down direction. One type of elevator starter, referred to as a soft starter, changes the on time of the solid state switches to control voltage and to ramp up motor current with a fixed connection. The motor controller 20 may be as generally described in pending application Ser. No. 10/252,326, assigned to the assignee of the present application, the specification of which is incorporated by reference herein. The motor controller 20 comprises a housing 22 including a housing base 24, a heat sink 26 and a cover 28. The motor controller 20 includes a plurality of solid state switches 32 in the form of thyristors, such as back to back connected silicon controlled rectifier (SCR) pairs, see FIG. 2. For simplicity herein, the SCR pairs are referred to as simply SCRs 32. Triacs could also be used. The SCRs 32 control application of three phase AC line power to a three phase motor. A different number of SCRs 32 could be used to control different numbers of phases, as is apparent to those skilled in the art. The SCRs 32 are mounted to the heat sink 26 within the housing 20. Referring also to FIG. 2, a control circuit 34 is also enclosed in the housing 20. The control circuit 34 controls operation of the SCRs 32 and monitors parameters such as line voltage, motor voltage and motor current by sensing SCR current from a current sensor I and voltage at either side of the SCRs 32 from a sensor V. Particularly, the control circuit 34 includes a programmed processor 36, such as a digital signal processor, operatively connected to the SCRs 32 for commanding operation of the SCRs 32 and measuring the power system values. A memory 38, such as an Eprom memory, is connected to the processor 36 and stores these and other parameters relating to motor operation and operation of the SCRs 32. A display and keypad user interface 40, comprising an LCD display 44 and actuator elements, such as push buttons 48, on the cover 28, see FIG. 1, is connected to the processor 36. The display 44 is used to indicate configuration settings, operating values, fault conditions, and the like. User actuable switches (not shown) are electrically connected to the processor 36 and are actuated by the actuator elements 48. Particularly, the actuator elements 48 are used for manually selecting parameters for display. In accordance with the invention, the motor controller 20 is adapted for communication with an external monitoring and diagnostic device 50 to define an electrical system monitoring and diagnostics system 52. The external monitoring and diagnostic device 50 comprises a computer 54. The computer 54 could be a conventional desktop computer, a laptop computer, or a personal digital assistant (PDA), or the like . In the illustrated embodiment of the invention, represented in FIG. 2, the computer 54 is adapted for wireless communication using infrared signaling or the like. For example, an infrared communication module is a standard element on commercially available PDAs. Similarly, wireless communication could be provided using currently available technologies such as Wi-Fi or Bluetooth. The computer 54 is connected to a memory 56. The memory 56 could be internal memory of the computer 54 or removable media, as necessary or desired. The memory 56 stores a monitoring and diagnostic program 58 implemented by the computer 54 and data uploaded from the motor controller 20. A printer 60 may be connected to the computer 54 to print configuration information. The computer 54 operates in accordance with various programs stored in the memory 56 and including the monitoring and diagnostics module 58 which transfers monitoring and diagnostics information from the motor controller 20. In accordance with the invention, an infrared module 62 is mounted to the motor controller cover 28 and is electrically connected to the processor 36 via a conventional interface circuit 64. The infrared module 62 allows communications with the computer 54 via a wireless communication path 63. The infrared module 62 provides necessary voltage isolation with the computer 54. Alternatively, and with reference to FIG. 3, the external device 50 could be hard wired using an electrically isolated serial cable 66 from the computer 54 to the interface circuit 64 for configuration. It should also be appreciated that the motor controller 20 could be configured or monitored from an external device over a network, such as the internet. As such, the cable 66 can represent the network or the external device 50 could be connected to the network in a conventional manner. As discussed above, the motor controller 20 includes a local user interface in the form of the display and keypad 40 on the housing 22 for locally monitoring parameters stored in the memory 38. Additionally, external electrical system monitoring and diagnostics is provided in the form of the external monitoring and diagnostic device 50 for selectively uploading stored monitoring and diagnostics information. As discussed above, the programmed processor 36 commands operation of the SCRs 32 and measures power system values such as voltage and current. More particularly, the processor 36 operates in accordance with conventional programs for commanding operation of the SCRs and uses various stored configuration parameters for determining the control sequence, such as during a soft start operation. The following table illustrates settings used by the programmed processor and parameters detected or determined by the programmed processor during normal operation: TABLE 1Starter Sub-Menu CategoryParameter/SettingParameter MenuStarting AmpsOverload AmpsLine RotationOff Delay mS.On Delay mS.OEM MenuStarting ModeOverload ModeAmp ImbalanceImbalance EnableLow Amp UTSCycle Fault ContactorStall DetectStall TimeStart Limit TimeEngineering MenuProp FactorInt FactorConfigurationMotor DetectionTest Code These settings and real time parameters are stored in the control circuit memory 38. As is apparent, with a three phase motor, the various parameters will be measured or determined for each phase independently, as necessary, in a conventional manner. The present invention is not directed to any particular scheme for motor control or to monitoring any particular characteristics, but rather providing electrical system monitoring and diagnosis in real time using information transferred from the motor controller 20. Referring to FIG. 4, a flow diagram illustrates the monitoring and diagnosis program implemented in the external monitoring and diagnostic device 50. The program begins at a start node 70. A decision block 72 determines if communications have been established with the motor controller 20 using either the wireless communication path 63 or the wired communication path 66. If not, the routine waits until communications are established. Thereafter, the user sets an update rate at a block 74. The update rate could be any desired rate such as once a second, ten times a second, one hundred times a second, as appropriate or as allowed by the appropriate communication path. One limitation on the rate would be the amount of memory 56 and the length of time for which monitoring and diagnosis is to be performed. The user then selects the parameters to be monitored at a block 76. The parameters could be any of the exemplary parameters noted above, or other parameters that are available in the motor controller memory 38. A start timer is then initiated at a block 78. Thereafter, monitoring and diagnosing is performed beginning at a block 80 which reads the parameters selected at the block 76 as by transferring the selected parameters from the motor controller memory 38 to the external monitoring and diagnostic device memory 56. These read parameters are used to update a data table at a block 82. A decision block 84, using the update rate set at the block 74, determines if it is time for the next update. If so, then the program returns to the block 80. If not, a decision block 86 determines if the table is to be printed. If so, then the data table is printed at a block 88. Thereafter, or if printing is not selected, then a decision block 90 determines if the user has stopped monitoring and diagnosis. If so, then the routine ends at a node 92. If not, then the program returns to the decision block 84 to determine if it is time for the next update. The following tables show examples of data tables that can be stored and printed with the external monitoring and diagnostic device 50. TABLE 2Feb. 20, 2004 08:36:26Starting Amps = 148 Overload Amps = 42Number of Starts = 31 Power Ups = 6PowerOnTime-Status-AmpAAmpBAmp DDly msOvl %0:37:36.2Start0006.3892.1Ramp0:37:36.2Start2225276.1892.1Ramp0:37:36.2Start2225276.1892.1Ramp0:37:36.4Current3233384.7992.6Limit0:37:36.6Current8891904.5793.3Limit0:37:36.6Current9091904.5394.0Limit0:37:37.0Current8992914.4996.0Limit0:37:37.0Current8991914.4696.7Limit0:37:37.0Current8991914.4696.7Limit0:37:37.2Current8991904.4697.3Limit0:37:37.2Current9092914.4498.0Limit0:37:37.4Current9091914.4099.4LimitCurrent Overload0:37:37.6Stopped6236696.50100.0 TABLE 3Feb. 20, 2004 08:36:18Starting Amps = 148 Overload Amps = 42Number of Starts = 29 Power Ups = 5AmpAmpAmpPowerOnTime-Status-ABDDly msOvl %0:37:30.8Start Ramp0006.3889.20:37:30.8Start Ramp2224246.3089.20:37:31.0Current Limit3942435.0489.40:37:31.2Current Limit8891894.5890.00:37:31.4Current Limit9092904.4391.40:37:31.6Current Limit8991894.3092.70:37:31.8Current Limit7369720.8593.50:37:32.0Upto Voltage2117180.0093.40:37:32.2Upto Voltage2016170.0093.30:37:32.4Upto Voltage2016170.0093.20:37:32.6Upto Voltage2016170.0093.20:37:32.8Upto Voltage1310180.0093.00:37:33.0Upto Voltage1414370.0093.00:37:33.2Upto Voltage1515360.0092.90:37:33.4Upto Voltage1515350.0092.90:37:33.6Upto Voltage1515370.0092.80:37:33.8Upto Voltage1515350.0092.70:37:34.0Upto Voltage1514370.0092.70:37:34.2Upto Voltage1515360.0092.60:37:34.4Upto Voltage1514370.0092.50:37:34.6Upto Voltage1515370.0092.40:37:34.8Upto Voltage1515370.0092.40:37:35.0Upto Voltage1515390.0092.30:37:35.2Upto Voltage2020550.0092.30:37:35.4Upto Voltage2323650.0092.50:37:35.6Upto Voltage2525700.0092.50:37:35.6Stopped2626726.5092.6 This monitored information can then be used by the technician to determine if there is an electrical system problem or some other type of problem. It can therefore be appreciated that a new and novel system and method for electrical system monitoring and diagnosis in a motor controller, such as a soft starter has been described. It will be appreciated by those skilled in the art that, given the teaching herein, numerous alternatives and equivalents will be seen to exist which incorporate the disclosed invention. As a result, the invention is not to be limited by the foregoing exemplary embodiments, but only by the following claims.
	claims	1. A method for treating carbonaceous radioactive waste, comprising the delivery of waste to one or more radioactive isotope separation stations, said isotopes being among at least carbon 14, chlorine 36, and tritium,wherein the delivery to each of the stations occurs in wet form,the method comprising:providing a leaching to separate the chlorine 36 and the tritium from the rest of the carbonaceous waste so as to deliver the chlorine 36 and the tritium in at least one first separation station, andafter separations of the chlorine 36 and the tritium from the rest of the carbonaceous waste, treating the rest of the carbonaceous waste so as to deliver the carbon 14 in a second separation station. 2. The method according to claim 1, wherein specific separation stations are provided for each element among the carbon 14, chlorine 36, and tritium, as well as delivery in wet form to each of said stations. 3. The method according to claim 1, wherein the waste is crushed and mixed with water for delivery in slurry form, before a first isotopic separation. 4. The method according to claim 1, wherein the waste is mixed with water to form a slurry, then mechanically filtered and dried, and wherein the water issuing from this drying contains all or part of the chlorine 36 initially present in the waste prior to drying. 5. The method according to claim 1, wherein, after separating the chlorine 36, the waste is calcined by roasting, then washed, and wherein the water recovered from the wash contains all or part of the tritium initially present in the waste prior to roasting. 6. The method according to claim 1, wherein, with at least a portion of the waste being calcined by roasting, the waste resulting from the roasting is oxidized to carbon dioxide form for dissolution in the conveying water. 7. The method according to claim 1, wherein the carbon 14 is put in carbon dioxide form for treatment by carbonation reaction, in order to be solidified and stored in solid form. 8. The method according to claim 1, wherein the carbonaceous waste initially contains graphite. 9. A facility for treating carbonaceous radioactive waste, comprising one or more radioactive isotope separation stations, said isotopes being among at least carbon 14, chlorine 36, and tritium, as well as means of delivering the waste to said stations,wherein the means of delivery are supplied with water in order to deliver the waste in wet form,said facility including a leaching stage to separate the chlorine 36 and the tritium from the rest of the carbonaceous waste and to deliver the chlorine 36 and the tritium in at least one first separation station of the facility, anda reactor for treating the rest of the carbonaceous waste so as to deliver the carbon 14 in a second separation station of the facility.
042010926	claims	1. A method of detecting and monitoring a leak caused by a through wall crack having a throat diameter in a high pressure fluid system comprising the following sequential steps: sensing the acoustic energy emitted by said wall crack, monitoring the change of said sensed energy over time, ascertaining that a choke flow condition exists wherein the escaping fluid velocity through said throat of said crack is sonic thus rendering the acoustic energy equal to a constant, k.rho..sub.o A.sup.3.sub.o, multiplied by the square of the crack throat diameter, determining any crack enlargement in accordance with said change of said sensed energy.
049888838	abstract	Fingernail light systems for curing photopolymerizable plastics on fingernails are known, having a housing with a bottom plate 7, in which housing a support body 4, having indentations 18 on its outer contour, is provided for positioning the fingers of the hand 5 to be irradiated, and having at least one irradiation lamp 14, which at least partially surrounds the support body in a spaced-apart manner in the irradiation position, the support body being accessible in the irradiation position via an opening 10 in the housing. In order to provide a system that meets the indicated needs and assures a uniform irradiation of all the fingernails of both the left and the right hand, with the light originating in the irradiation lamp substantially striking the fingernails (20-24) to be cured, in which fingernails of even great length can be irradiated and a comfortable hand posture can be maintained, even over a relatively long period on the order of half a minute, the support body 4 of the present invention features an approximately cylindrical (FIG. 1) or frusto-conical (FIG. 3 ) outer contour, at least in the vicinity of the indentations, and the indentations are in the form of channels 18 that extend substantially in the direction of the axis of the support body, and the axis 3 of the support body 4 forms an angle in the range from 0.degree. to 90.degree. with the direction 31 orthogonal to bottom plate 7.
063339579	claims	1. A tool kit for ensuring rotational orientation of a pair of tie bars having flats adjacent upper ends thereof wherein the tie bars form part of a water rod assembly in a nuclear fuel bundle, the water rod assembly including a pair of water rods, the pair of tie bars and pair of water rods having releasable locking subassemblies for respectively securing the tie bars and water rods to one another forming joints therebetween, comprising: first and second gauges each having a gauge body with first and second openings generally complementary in shape to the respective upper ends of the tie bars having said flats, said openings having parallel axes, margins of each gauge body defining the openings being offset from one another in the direction of said axes, the openings of the second gauge being reduced in diameter relative to the openings in the first gauge body whereby the rotational orientation of the water rods about their respective axes is ensured upon application of the first and second gauges to the tie bars. a pair of wrenches having wrench heads including openings respectively complementary in shape to the flats at the upper ends of the tie bars and reference points on the wrench heads for alignment with one another upon engagement of the tie bar upper ends in the wrench head openings to align the water rods with one another rotationally about their respective axes; and at least one gauge having a gauge body with first and second openings generally complementary in shape to the respective upper ends of the tie bars having said flats, said openings having parallel axes, margins of the gauge body defining the openings being offset from one another in the direction of said axes whereby rotational orientation of the water rods about their respective axes is adjusted upon application of the one gauge to said tie bars. providing first and second gauges each having a gauge body with first and second openings generally complementary in shape to the respective upper ends of the tie bars having the flats; providing margins for each gauge body defining the openings axially offset from one another in the direction of said axes; providing openings in the second gauge of reduced diameter relative to the openings in the first gauge; and successively applying the first and second gauges to the upper ends of the tie bars to ensure rotational orientation of the water rods about their respective axes. providing a pair of wrenches having wrench heads including openings respectively complementary in shape to the flats at the upper ends of the tie bars with reference points on the wrench heads; applying the pair of wrenches to the upper ends of the tie bars and aligning the reference points on the wrench heads with one another to align the water rods with one another rotationally about their respective axes; providing at least one gauge with first and second openings generally complementary in shape to the respective upper ends of the tie bars having said flats, with margins of the openings being axially offset from one another in the direction of the axes; and adjusting the rotational orientation of the water rods relative to one another by applying the one gauge to the upper ends of the tie rods having the flats. applying the second gauge to the upper ends of the tie bars with the flats to adjust the angular orientation of the respective water rod assemblies relative to one another about their axes. 2. A tool kit according to claim 1 including a third gauge having a gauge body with first and second openings generally complementary in shape to the respective upper ends of the tie bars having flats, said openings of said third gauge having parallel axes and being reduced relative to the openings in the first and second gauge bodies, margins of the third gauge body defining the openings being offset from one another in the direction of the axes whereby rotational orientation of the water rods about their respective axes is adjustable. 3. A tool kit for adjusting rotational orientation of a pair of tie bars having flats adjacent upper ends thereof wherein the tie bars form part of a water rod assembly in a nuclear fuel bundle, the water rod assembly including a pair of water rods, the pair of tie bars and pair of water rods having releasable locking subassemblies for respectively securing the tie bars and water rods to one another forming joints therebetween, comprising: 4. A tool kit according to claim 3 including a second gauge having a gauge body with first and second openings generally complementary in shape to the respective upper ends of the tie bars having the flats, said openings of said second gauge having parallel axes and being reduced in diameter relative to the openings in the first gauge body, margins of the second gauge body defining the openings being offset from one another in the direction of the axes whereby rotational orientation of the water rods about their respective axes is adjustable. 5. A tool kit according to claim 4 including a third gauge having a gauge body with first and second openings generally complementary in shape to the respective upper ends of the tie bars having the flats, said openings of said third gauge having parallel axes and being reduced in diameter relative to the openings in the second gauge body, margins of the third gauge body defining the openings being offset from one another in the direction of the axes whereby rotational orientation of the water rods about their respective axes is adjustable. 6. A took kit according to claim 3 including a cap having a cap body with first and second openings generally complementary in shape to the respective upper ends of the tie bars for maintaining orientation of the water rod assemblies about their axes during handling of the fuel bundle. 7. A tool kit according to claim 3 wherein said locking subassembly includes a threaded washer having a pair of flats, and including a wrench having an opening substantially complementary in shape to the threaded washer with flats including a head having a pair of opposing jaws, a base between said jaws at one end of said opening, the junctures between said jaws and said base having reliefs for precluding rounding off corners of the threaded washer. 8. A tool kit according to claim 3 including a socket having a recess complementary in shape with the shape of the flats at the upper ends of the tie bars and opening through one end of the socket for receiving the tie bar upper ends within said recess and a square aperture at its opposite end for receiving the driver of a driving tool whereby, with the socket recess received about the tie rod ends, the tie rods and/or water rods are rotatable by rotation of the socket. 9. A tool kit according to claim 3 including a second gauge having a gauge body with first and second openings generally complementary in shape to the respective upper ends of the tie bars having the flats, said openings of said second gauge having parallel axes and being reduced in diameter relative to the openings in the first gauge body, margins of the second gauge body defining the openings being offset from one another in the direction of the axes whereby rotational orientation of the water rods about their respective axes is adjustable, and a cap having a cap body with first and second openings generally complementary in shape to the respective upper ends of the tie bars for adjusting orientation of the water rod assemblies about their axes during handling of the fuel bundle. 10. A tool kit according to claim 3 including a second gauge having a gauge body with first and second openings generally complementary in shape to the respective upper ends of the tie bars having the flats, said openings of said second gauge having parallel axes and being reduced in diameter relative to the openings in the first gauge body, margins of the second gauge body defining the openings being offset from one another in the direction of the axes whereby rotational orientation of the water rods about their respective axes is adjustable, each said locking subassembly including a threaded washer having a pair of flats, and including a wrench having an opening substantially complementary in shape to the threaded washer with flats including a head having a pair of opposing jaws, a base between said jaws at one end of said opening, the juncture between said jaws and said base having reliefs for precluding rounding off corners of the threaded washer. 11. A tool kit according to claim 3 including a second gauge having a gauge body with first and second openings generally complementary in shape to the respective upper ends of the tie bars having the flats, said openings of said second gauge having parallel axes and being reduced in diameter relative to the openings in the first gauge body, margins of the second gauge body defining the openings being offset from one another in the direction of the axes whereby rotational orientation of the water rods about their respective axes is adjustable, and a socket having a recess complementary in shape with the shape of the flats at the upper ends of the tie bars and opening through one end of the socket for receiving the tie bar upper ends within said recess and a square aperture at its opposite end for receiving the driver of a driving tool whereby, with the socket recess received about the tie rod ends, the tie rods and/or water rods are rotatable by rotation of the socket. 12. A tool kit according to claim 3 including a second gauge having a gauge body with first and second openings generally complementary in shape to the respective upper ends of the tie bars having the flats, said openings of said second gauge having parallel axes and being reduced in diameter relative to the openings in the first gauge body, margins of the second gauge body defining the openings being offset from one another in the direction of the axes, a third gauge having a gauge body with first and second openings generally complementary in shape to the respective upper ends of the tie bars having the flats, said openings of said third gauge having parallel axes and being reduced in diameter relative to the openings in the second gauge body, margins of the third gauge body defining the openings being offset from one another in the direction of the axes whereby rotational orientation of the water rods about their respective axes is adjustable, and a cap having a cap body with first and second openings generally complementary in shape to the respective upper ends of the tie bars for maintaining orientation of the water rod assemblies about their axes during handling of the fuel bundle. 13. A tool kit according to claim 3 including a second gauge having a gauge body with first and second openings generally complementary in shape to the respective upper ends of the tie bars having the flats, said openings of said second gauge having parallel axes and being reduced in diameter relative to the openings in the first gauge body, margins of the second gauge body defining the openings being offset from one another in the direction of the axes whereby angular orientation of the water rods about their respective axes is adjustable, a third gauge having a gauge body with first and second openings generally complementary in shape to the respective upper ends of the tie bars having the flats, said openings of said third gauge having parallel axes and being reduced in diameter relative to the openings in the second gauge body, margins of the third gauge body defining the openings being offset from one another in the direction of the axes whereby rotational orientation of the water rods about their respective axes is adjustable, said locking subassembly including a threaded washer having a pair of flats, and a wrench having an opening substantially complementary in shape to the threaded washer with the flats including a head having a pair of opposing jaws, a base between said jaws at one end of said opening, the juncture between said jaws and said base having reliefs for precluding rounding off corners of the threaded washer. 14. A tool kit according to claim 3 including a second gauge having a gauge body with first and second openings generally complementary in shape to the respective upper ends of the tie bars having the flats, said openings of said second gauge having parallel axes and being reduced in diameter relative to the openings in the first gauge body, margins of the second gauge body defining the openings being offset from one another in the direction of the axes whereby rotational orientation of the water rods about their respective axes is adjustable, a third gauge having a gauge body with first and second openings generally complementary in shape to the respective upper ends of the tie bars having the flats, said openings of said third gauge having parallel axes and being reduced in diameter relative to the openings in the second gauge body, margins of the third gauge body defining the openings being offset from one another in the direction of the axes whereby rotational orientation of the water rods about their respective axes is adjustable and a socket having a recess complementary in shape with the shape of the flats at the upper ends of the tie bars and opening through one end of the socket for receiving the tie bar upper ends within said recess and a square aperture at its opposite end for receiving the driver of a driving tool whereby, with the socket recess received about the tie rod ends, the tie rods and/or water rods are rotatable by rotation of the socket. 15. A tool kit according to claim 3 including a cap having a cap body with first and second openings generally complementary in shape to the respective upper ends of the tie bars for maintaining orientation of the water rod assemblies about their axes during handling of the fuel bundle, said locking subassembly including a threaded washer having a pair of flats, and a wrench having an opening substantially complementary in shape to the threaded washer with flats including a head having a pair of opposing jaws, a base between said jaws at one end of said opening, the juncture between said jaws and said base having reliefs for precluding rounding off corners of the threaded washer. 16. A tool kit according to claim 3 wherein said locking subassembly includes a threaded washer having a pair of flats, and including a wrench having an opening substantially complementary in shape to the threaded washer with flats including a head having a pair of opposing jaws, a base between said jaws at one end of said opening, the juncture between said jaws and said base having reliefs for precluding rounding off corners of the threaded washer, a socket having a recess complementary in shape with the shape of the flats at the upper ends of the tie bars and opening through one end of the socket for receiving the tie bar upper ends within said recess and a square aperture at its opposite end for receiving the driver of a driving tool whereby, with the socket recess received about the tie rod ends, the tie rods and/or water rods are rotatable by rotation of the socket. 17. A tool kit according to claim 1 wherein said axially offset margin about a first opening of said first gauge enables rotation of said first gauge and a tie bar received in a second opening of said first gauge relative to another of said tie bars to a rotational position axially aligning said first opening of said first gauge with said another tie bar. 18. A tool kit according to claim 17 wherein said axially offset margin about a first opening of said second gauge enables rotation of said second gauge and a tie bar received in a second opening of said second gauge relative to another of said tie bars to a rotational position axially aligning said first opening of said second gauge with said another tie bar. 19. A tool kit according to claim 3 wherein said axially offset margin about a first opening of said one gauge enables rotation of said one gauge and a tie bar received in a second opening of said one gauge relative to another of said tie bars to a rotatable position axially aligning said first opening of said one gauge with said another tie bar. 20. In a nuclear fuel bundle including tie bars with flats adjacent upper ends thereof forming part of a water rod assembly having a pair of water rods, the pair of tie bars and pair of water rods having releasable locking assemblies for respectively securing the tie bars and water rods to one another forming joints therebetween, a method for ensuring rotational orientation of the respective tie bars and water rods relative to one another, comprising the steps of: 21. In a nuclear fuel bundle including tie bars with flats adjacent upper ends thereof forming part of a water rod assembly having a pair of water rods, the pair of tie bars and pair of water rods having releasable locking assemblies for respectively securing the tie bars and water rods to one another forming joints therebetween, a method for ensuring rotational orientation of the tie bars and water rods, respectively, relative to one another, comprising the steps of: 22. A method according to claim 21 including providing a second gauge having a gauge body with first and second openings generally complementary in shape to the respective upper ends of the tie bars having the flats, providing said openings of the second gauge with reduced diameters relative to the openings of the first gauge body with margins of the second gauge body defining the openings being offset from one another in the direction of the axes; and 23. A method according to claim 21 including providing a cap having a cap body with first and second openings generally complementary in shape to the respective upper ends of the tie bars and applying the cap body to the upper ends of the tie bars for maintaining orientation of the water rod assemblies about their axes during handling of the fuel bundle.
	abstract	A self-magnetically confined lithium plasma which also may have an applied axial magnetic field is irradiated at sub-critical density by a carbon dioxide laser to generate extreme ultraviolet photons at the wavelength of 13.5 nm with high efficiency, high power and small source size.
	summary
	description	This application is a continuation of U.S. patent application Ser. No. 14/439,736, filed Apr. 30, 2015, now U.S. Pat. No. 10,258,299, issued Apr. 16, 2019, which application is a national phase entry under 35 U.S.C. § 371 of International Patent Application PCT/US2012/062672, filed Oct. 31, 2012, designating the United States of America and published in English as International Patent Publication WO 2014/070151 A1 on May 8, 2014, the entire contents and disclosure of each of which is hereby incorporated herein by this reference. The present application relates to the field of imaging, and, in particular, computed tomography (CT) imaging where volumetric data of an object under examination is generated. It finds particular utility in medical applications, where a pre-object filter may be utilized to reduce a dosage of radiation applied to a patient. However, it may also find utility in security and/or industrial applications, where radiation is utilized to examine and/or image an object. CT imaging modalities are useful to provide information, or images, of interior aspects of an object under examination. Generally, the object is exposed to radiation photons (e.g., such as X-rays, gamma rays, etc.), and an image(s) is formed based upon the radiation absorbed and/or attenuated by the interior aspects of the object, or rather an amount of photons that is able to pass through the object. Traditionally, the image(s) that is formed from the radiation exposure is a density image or attenuation image, meaning the image is colored/shaded as a function of the respective densities of sub-objects comprised within the object under examination. For example, highly dense sub-objects absorb and/or attenuate more radiation than less dense sub-objects, and thus a sub-object having a higher density, such as a bone or metal, for example, will be shaded differently than less dense sub-objects, such as muscle or clothing. However, more recently, multi-energy imaging systems (e.g., such as dual-energy CT scanners) have been utilized to discriminate sub-objects based upon more than density. Such systems are typically configured to distinguish sub-objects based upon density and other physical characteristics, such as atomic number, for example. In some applications, such as medical imaging, it may be desirable to reduce (e.g., to a minimum) the dosage of radiation applied to a patient while achieving a desired image quality. Numerous techniques have been developed to preserve/improve image quality while reducing dosage to a patient. For example, current modulation techniques (e.g., which modulate a current applied to a radiation source) and iterative image reconstruction techniques have provided ways to preserve/improve image quality while reducing dosage to a patient. Another technique for achieving such a result is through the use of a pre-object filter, such as a bowtie filter, for example, which is inserted into a radiation beam path to shape a profile of the radiation beam to facilitate reducing dosage to a patient. Such pre-object filters have proven effective for reducing dosage (e.g., by up to 50% or more). However, due to their high cost and complexity, such pre-object filters are typically not tailored (e.g., optimized) for respective anatomical regions and/or patient sizes. For example, conventional scanners typically have, at most, two pre-object filters. A first pre-object filter corresponds to an average head size of a human patient and a second pre-object filter corresponds to an average body size of a human patient. As such, the pre-object filters may not be well suited for patients not conforming to average sizes (e.g., such as larger/smaller adults, children, etc.), causing radiation flux to less precisely match some patients relative to others. Aspects of the present application address the above matters, and others. According to one aspect, an apparatus for a computed tomography (CT) system is provided. The apparatus comprises a pre-object filter configured to shape a profile of radiation attenuation in a fan-angle direction as a function of a profile of an object being examined. The pre-object filter is configured for at least one of translations in a direction substantially parallel to an axis of rotation for a rotating gantry of the CT system or at least partial rotation about a filter axis substantially parallel to the fan-angle direction. According to another aspect, a method for imaging a patient is provided. The method comprises acquiring a profile of the patient, the profile describing one or more features of the patient. The method also comprises performing an imaging scan on the patient and shaping, as a function of the profile of the patient, a profile of radiation attenuation in a fan-angle direction to affect an amount of radiation attenuated in the fan-angle direction. The shaping occurs at least one of prior to performing the imaging scan or during the imaging scan. According to yet another aspect, a computed tomography (CT) system is provided. The system comprises a radiation source, a detector array, and a rotating gantry configured to rotate the radiation source and the detector array about an object under examination. The system also comprises a pre-object filter positioned between the radiation source and the object and configured to shape a profile of radiation attenuation as a function of a profile of the object. Shaping the profile of the radiation attenuation comprises at least one of translating the pre-object filter in a direction substantially parallel to an axis of rotation for the rotating gantry, rotating the pre-object filter about a filter axis substantially parallel to a fan-angle direction, or oscillating the pre-object filter about the filter axis. The claimed subject matter is now described with reference to the drawings, wherein like reference numerals are generally used to refer to like elements throughout. In the following description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the claimed subject matter. It may be evident, however, that the claimed subject matter may be practiced without these specific details. In other instances, structures and devices are illustrated in block diagram form in order to facilitate describing the claimed subject matter. Among other things, one or more systems and/or techniques are described for shaping a profile of radiation attenuation in a fan-angle direction based upon a profile of an object undergoing an examination. For example, a pre-object (e.g., pre-patient) filter may be configured to adjust an amount of radiation attenuated in the fan-angle direction between examinations (e.g., of different patients and/or of different anatomical regions) and/or during an examination of a patient. Various designs of pre-object filters are described herein for shaping radiation attenuation as a function of a profile of an object to be examined and/or presently under examination. Such a profile may describe, among other things, a size of the object, a shape of the object, and/or a position of the object relative to a support article configured to support the object (e.g., a degree of off-set relative to a center line of the support article), for example. In this way, a pre-object filter configured for adjustment based upon a size, shape, and/or location of an object, for example, may (e.g., dynamically) adjust an amount of radiation attenuated in the fan-angle direction in a desired manner, for example. Shaping a profile of radiation attenuation via the pre-object filter based upon the profile of the object may, for example, reduce the dosage of radiation to the object while providing desired imaging specification (e.g., a specified imaging quality). Moreover, in one embodiment, by shaping a profile of radiation attenuation based upon the profile of the object, radiation flux impinging a detector array may be substantially equalized, which may be particularly useful with respect to photon counting and/or energy discriminating detector arrays (e.g., which may have a limited dynamic range relative to charge integrating detector arrays). That is, by substantially equalizing flux via the pre-object filter, pulse pile-up (e.g., caused by high flux rates) may be mitigated. Moreover, even with respect to charge integrating detector arrays, equalizing flux may be beneficial to facilitate the use of higher gains (e.g., which may improve noise performance (e.g., signal-to-noise ratio) and therefore result in better image quality and/or better low contrast detectability), for example. FIG. 1 illustrates an example environment 100 wherein one or more of the techniques and/or systems described herein may find applicability. More particularly, FIG. 1 illustrates an example computed tomography (CT) system configured to examine an object(s) 102 (e.g., a patient, suitcase, etc.) and generate one or more images therefrom. It may be appreciated that while specific reference is made herein to CT systems, the instant application may find applicability to other radiation imaging systems (e.g., such as digital/projection radiology, mammography, etc.) where varying an amount of radiation attenuation in a fan-angle direction may be useful, and thus is not limited to CT. In the example environment 100, an examination unit 108 of the imaging modality is configured to examine one or more objects 102 (e.g., human patients, animal patients, bags, etc.). The examination unit 108 can comprise a rotating gantry 104 and a (stationary) support structure 110 (e.g., which may encase and/or surround as least a portion of the rotating gantry 104 (e.g., as illustrated with an outer, stationary ring, surrounding an outside edge of an inner, rotating ring)). During an examination of the object(s) 102, the object(s) 102 can be placed on a support article 112, such as a bed or conveyor belt, for example, that is selectively positioned in an examination region 114 (e.g., a hollow bore in the rotating gantry 104), and the rotating gantry 104 can be rotated and/or supported about the object(s) 102 by a rotator 116, such as a motor, drive shaft, chain, roller truck, etc. The rotating gantry 104 may surround a portion of the examination region 114 and may comprise a radiation source 118 (e.g., an ionizing x-ray source, gamma radiation source, etc.) and a detector array 106 that is mounted on a substantially diametrically opposite side of the rotating gantry 104 relative to the radiation source(s) 118. During an examination of the object(s) 102, the radiation source(s) 118 emits fan, cone, wedge, and/or other shaped radiation 120 configurations from a focal spot(s) of the radiation source 118 (e.g., a region within the radiation source 118 from which radiation 120 emanates). The example environment 100 further comprises a pre-object filter 119. The pre-object filter, which may be positioned between the radiation source 118 and the examination region 114 (and more particularly, the object 102), is configured to attenuate, in a fan-angle direction, at least a portion of the emitted radiation 120 to shape the emitted radiation 120. Such shaping may occur during an examination of the object 102 and/or between examinations of different objects. By way of example, prior to an imaging scan (e.g., from which diagnostic images are generated), a profile of the object 102 may be developed (e.g., using a pre-scan technique and/or by entering measurements of the object 102 into the CT system). Using this profile, a pre-object filter manipulator 134 may be configured to generate instructions for adjusting the pre-object filter (e.g., to shape a profile of radiation attenuation in the fan-angle direction as a function of the object being scanned). Further, in another embodiment, the pre-object filter manipulator may receive information pertaining to a present gantry rotation angle and/or a rotation speed for the rotating gantry 104, and the pre-object filter manipulator 134 may adjust the pre-object filter based upon the gantry rotation angle and/or a speed of rotation, for example. The pre-object filter manipulator (e.g., which may be located on the stationary side of the imaging modality and/or on the rotating gantry 104), may be configured to provide information to the pre-object filter 119 regarding adjustment information, such as how the pre-object filter 119 is to be translated, rotated, and/or oscillated, for example. In one embodiment, such adjustment information may be provided based upon the profile of the object 102. In another embodiment, the pre-object filter manipulator 134 may be configured to receive information relating to the rotating gantry 104 from a controller 132, such as information corresponding to a speed of rotation, and the object filter manipulator may be configured to specify how the pre-object filter is to be adjusted based upon the information relating to the rotating gantry 104, for example. Emitted radiation 120 that traverses the object(s) 102 may be attenuated differently by different aspects of the object(s) 102. Because different aspects attenuate different amounts of the radiation 120, an image(s) may be generated based upon the attenuation, or variations in the number of photons that are detected by cells of the detector array 106. For example, more dense aspects of the object(s) 102, such as a bone or metal plate, may attenuate more of the radiation 120 (e.g., causing fewer photons to strike the detector array 106) than less dense aspects, such as skin or clothing. The detector array 106 is configured to directly convert and/or indirectly convert detected radiation into signals that can be transmitted from the detector array 106 to a data acquisition component 122 configured to compile signals that were transmitted within a predetermined time interval, or measurement interval, using various techniques (e.g., integration, photon counting, etc.). It may be appreciated that such a measurement interval may be referred to as a “view” and generally reflects signals generated from radiation 120 that was emitted while the radiation source 118 was at a particular angular range relative to the object(s) 102. Based upon the compiled signals, the data acquisition component 122 can generate projection data indicative of the compiled signals, for example. The example environment 100 also illustrates an image reconstructor 124 that is operably coupled to the data acquisition component 122 and is configured to generate one or more images representative of the object(s) 102 under examination based at least in part upon signals output from the data acquisition component 122 using suitable analytical, iterative, and/or other reconstruction technique (e.g., tomosynthesis reconstruction, filtered back-projection, iterative reconstruction, etc.). For example, in a CT imaging application, the image reconstructor 124 may be configured to generate one or more image slices of the object(s) 102, respectively representative of a portion, or slice, of the object(s) 102. Such image slices may be combined, for example, to generate one or more images for presentation to a user 130, for example. The example environment 100 also includes a terminal 126, or workstation (e.g., a computer), configured to receive image(s) from the image reconstructor 124, which can be displayed on a monitor 128 to a user 130 (e.g., security personnel, medical personnel, etc.). In this way, the user 130 can inspect the image(s) to identify areas of interest within the object(s) 102. The terminal 126 can also be configured to receive user input which can direct operations of the examination unit 108 (e.g., a speed of gantry rotation, an energy level of the radiation, etc.). In the example environment 100, a controller 132 is operably coupled to the terminal 126. In one example, the controller 132 is configured to receive user input from the terminal 126 and generate instructions for the examination unit 108 indicative of operations to be performed (e.g., such as a rotation speed of the rotating gantry 104). The controller 132 may also be configured to receive information from the examination unit 108, such as, for example, information related to a gantry rotation angle. It may be appreciated that the components of the illustrated CT imaging modality and/or the features described with respect to respective components are intended to provide an example configuration and are not intended to be construed as limiting the scope of the instant application, including the claims. That is, an imaging modality may comprise additional components and/or different components than those described above and/or one or more of the described components may be configured to perform additional and/or different actions. Moreover, the arrangement of components may be different than the illustrated arrangement. For example, in one embodiment, the data acquisition component 122 may be coupled to the detector array 106 and mounted to the rotating gantry 104. FIG. 2 is a functional diagram 200 of a helical scan performed via a CT imaging modality, such as in medical and/or security applications. In such an imaging modality, an object 202 (e.g., 102 in FIG. 1) under examination is translated 204 (e.g., at either constant speed or in a step-and shoot manner) in a direction parallel to an axis of rotation (e.g., the object is translated along a z-axis), via an object support 206 (e.g., 112 in FIG. 1). During the translations and/or between translations, one or more radiation sources 208 (e.g., 118 in FIG. 1) and a detector array 210 (e.g., 106 in FIG. 1) are rotated about the object. In this way, a helical scan of the object is performed (e.g., where the radiation source(s) 208 and detector array 210 do not move in the z-direction, and thus the helical trajectory 212 is established by the combination of the x/y rotation of the radiation source 208 and detector array 210 and the z-direction translation 204 of the object 202). It may be appreciated that as used herein, helical scan, helical scanning, and/or the like is intended to describe both translation of the object at a constant speed and periodic translation (e.g., such as performed with respect to step-and-shoot). It may be appreciated that for purposes of the instant application, the z-direction (e.g., at times also referred to as axial direction) may be defined as a direction parallel to the axis of rotation. Typically, the object 202 is translated in the z-direction. The detector array 210 may be said to have a z-direction and an x-direction (e.g., although it may have some y-component due to an arcuate shape of the detector array 210). Thus, the x-direction may be a direction of the detector array 210 that is perpendicular to the z-direction. The y-direction may be defined as the dimension extending between the radiation source 208 and the detector array 210. Typically, the trajectory of radiation is predominately in the y-direction, although the trajectory may have an x-component or a z-component. It may be appreciated that relative orientations may change as elements rotate and/or move (e.g., because the dimensions, as defined, track the radiation source 208 and detector array 210). Radiation 214 may be emitted from the radiation source 208 in a multitude of directions. In one example, emitted radiation 214 may form a cone shape (e.g., in x, y and z directions) as it emanates from the radiation source 208 to the detector array 210, which may at times be referred to as a cone beam. In another example, emitted radiation 214 may form a fan shape (e.g., in x, y directions) as it emanates from the radiation source 208 to the detector array 210, which may at times be referred to as a fan beam. It may be appreciated that a cone beam may be said to comprise one or more fan beams. For example, where a fan beam is comprised within an x, y plane, a cone beam may comprise multiple fan beams that are ‘stacked’ on top of one another or adjacent to one another in the z direction. Adjacent fan beams (that represent slices through the conical shaped cone beam) may vary in width, where a centermost fan beam (slicing through the greatest diameter of the cone beam) may have a greatest width and outmost fan beams may have a smallest width. For purposes of the instant application, the trajectory of emitted radiation may be described in terms of at least two directional components: a cone-angle direction and a fan-angle direction. The cone-angle direction typically refers to a direction substantially parallel to the axis of rotation for the rotating gantry. The fan-angle direction typically refers to a direction substantially perpendicular to the axis of rotation for the rotating gantry and describes a direction in which the fan spreads out (e.g., a direction along which the fan elongates or becomes wider as radiation moves from the radiation source 208 to the detector array 210). Thus, based upon the foregoing definitions of the x, y, and z, directions, the cone-angle direction may be described as the z-direction and the fan-angle direction may be described as the x-direction. Also for purposes of the instant application, a gantry rotation angle is generally defined as a number of degrees that the rotating gantry has rotated away from a predefined zero-degree reference. For example, 0 degrees may be defined as a position of the rotating gantry that causes the radiation source 208 to be positioned directly above the object 202. Thus, when the rotating gantry rotates (e.g., within the x, y plane) such that the radiation source 208 becomes positioned directly below the object 202 (and the detector array 210 is directly above or over the object 202), the gantry rotation angle may be approximately 180 degrees. A pre-object filter (e.g., such as a bow-tie filter) is configured to shape a profile of radiation attenuation in the fan-angle direction (e.g., x-direction) by attenuating at least some radiation emitted in the fan-angle direction more than other radiation emitted in the fan-angle direction. Typically, the portion of the radiation that is attenuated to a greater degree by the pre-object filter is a portion of the radiation that may not be attenuated by the object (e.g., because the trajectory of the radiation does not intersect the object). In this way, the pre-object filter facilitates reducing significant differences in radiation flux received at different portions of the detector array. As used herein, fan-angle 310 and/or the like is intended to describe an overall angle at which radiation fans out (e.g., in the x-direction), and unattenuated fan-angle 308 and/or the like is intended to describe a portion of the fan-angle corresponding to radiation intended to intersect the object and thus is attenuated to a lesser degree by the pre-object filter (e.g., relative to the remainder of the fan-angle corresponding to radiation that is attenuated by the pre-object filter). It may thus be appreciated that ‘unattenuated’ fan-angle does not necessarily mean zero percent attenuation, but rather some reduction in attenuation as compared to attenuation of radiation in other parts of the fan angle. As an example, FIGS. 3-4 illustrate how a pre-object filter may shape a profile of radiation attenuation in the fan-angle direction based upon a profile (e.g., a size and/or shape) of an object. More particularly, FIGS. 3-4 illustrate an elliptically shaped object 302 (e.g., which may approximate a cross-section through a torso of a human patient) undergoing an examination/scan. The outer circle 304 represents a trajectory of a rotating gantry supporting a radiation source 306 (e.g., 208 in FIG. 2) and a detector array (not shown). In the example embodiment, the object 302 is wider when viewed from the top or bottom of the page (e.g., 0 degrees or 180 degrees) than when viewed from the side (e.g., 90 degrees or 270 degrees). Thus, it may be desirable to adjust the unattenuated fan-angle 308 during an examination according to the orientation of the radiation source 306 (e.g., or a gantry rotation angle of the rotating gantry) relative to the object 302. For example, when the radiation source 306 is at 0 degrees as illustrated in FIG. 3, a larger portion of radiation emitted in the fan-angle direction has a trajectory that intersects the object 302 than when the radiation source is at 90 degrees as illustrated in FIG. 4. As such, the pre-object filter may be configured to attenuate a greater portion of the radiation in the fan-angle direction at 90 degrees than at 0 degrees, causing the unattenuated fan-angle 308 to be smaller at 90 degrees (FIG. 4) than at 0 degrees (FIG. 3). It will thus be appreciated that the pre-object filter may (e.g., dynamically) shape a profile of radiation attenuation in the fan-angle direction (e.g., and vary an amount of radiation attenuated) as the rotating gantry rotates (e.g., through different gantry rotation angles) and views the object from different perspectives. In this manner, the unattenuated fan-angle 308 is adjusted as the rotating gantry rotates during a scan of the object. FIG. 5 illustrates an example pre-object filter 500 configured to shape a profile of radiation attenuation in a fan-angle direction as a function of a profile of an object being examined. Such a pre-object filter 500 may be comprised of aluminum, copper, Teflon, and/or other materials that are at least partially opaque to radiation (e.g., and can thus attenuate a portion of the radiation impinging the pre-object filter 500). In another embodiment, at least some of the pre-object filter 500 may be comprised of a less radiation opaque material(s) than the foregoing described materials. The example pre-object filter 500 defines a channel 502 extending in a direction substantially parallel to the axis of rotation for a rotating gantry (e.g., extending in the z-direction) from a first end 504 of the pre-object filter 500 to a second end 506 of the pre-object filter 500. In the illustrated embodiment, a sidewall 508 of the pre-object filter 500 that defines the channel 502 is curved such that a cross-section of the channel 502 (e.g., illustrating an x-y plane) may have the shape of a parabola. In other embodiments, the sidewall 508 may be shaped differently, causing the shape of the channel 502 to be different. For example, in another embodiment, sections of the sidewall 508 may meet at 90-degree angles, causing a cross-section of the channel 502 to appear more rectangular or square. Further, while the illustrated embodiment provides for the channel 502 extending from the first end 504 to the second end 506 of the pre-object filter 500, in another embodiment, the channel 502 may not extend the entire length of the pre-object filter 500. As such, at least one of the first end 504 and/or the second end 506 may not be shaped to facilitate the channel 502 (e.g., to provide an entry-way into the channel 502). As illustrated, the channel 502 is formed through on a top surface 510 of the pre-object filter 500 (e.g., such that the channel 502 is accessible through the top surface 510). In another embodiment, the channel 502 may be a hollow bore in the pre-object filter 500, which is enclosed by the sidewall 508 and the top surface 510 (e.g., such that the channel 502 takes that shape of a tunnel carved into and/or through the pre-object filter 500). The pre-object filter 500 may be shaped such that the width (e.g., measured in the x-direction) of the channel 502 decreases from the first end 504 to the second end 506. For example, a width 512 of the channel 502 at or near the first end 504 (e.g., at a first cross-sectional slice through the channel 502) may be greater than a width 514 of the channel 502 at or near the second end 506 (e.g., at a second cross-sectional slice). As such, a volume of a cross-sectional slice associated with (e.g., proximate) the first end 504 may be less than a volume of a (e.g., same number of) cross-section slice associated with (e.g., proximate) the second end 506 because the channel 502 occupies a larger amount of space proximate the first end 504 than proximate the second end 506, for example. In the illustrated embodiment, the width of the channel 502 decreases smoothly from the first end 504 to the second end 506 (e.g., such that the sidewall 508 is smooth from the first end 504 to the second end 506). In another embodiment, the width of the channel 502 may decrease in a non-uniform manner, such as, for example, incrementally in a stair-step manner between the first end 504 and the second end 506 (e.g., causing the sidewall 508 to appear jagged). Typically, at any given time, radiation passes through merely a relatively small cross-sectional slice of the pre-object filter 500 (e.g., where the thickness of the slice is defined by the z-dimension of the slice). The thicker the pre-object filter 500 (in the y-dimension), the greater the amount of radiation that is attenuated. Thus, radiation having a trajectory through the channel 502 may experience less attenuation than radiation having a trajectory through portions of the pre-object filter 500 that do not comprise the channel 502 (e.g., and are thus thicker in the y-dimension). To alter which portion (or cross-sectional slice) of the pre-object filter 500 is exposed to radiation, the pre-object filter 500 may be configured for translation in a direction parallel to the axis of rotation and/or parallel to the channel 502 (e.g., in the z-direction). By moving (e.g., translating in the z-direction) the pre-object filter 500 from a first position to a second position, the unattenuated fan-angle (e.g., corresponding to radiation traversing the channel 502 and thus being attenuated to a lesser degree) is increased/decreased to decrease/increase the amount of radiation that is attenuated by the pre-object filter 500. For example, if the pre-object filter 500 was translated to cause the second end 506 to be exposed to radiation as opposed to the first end 504, a greater amount of radiation may be attenuated (e.g., because the first end 504 is configured to attenuate a lesser amount of radiation due to the channel 502 being wider at the first end 504 than at the second end 506). In this way, the pre-object filter 500 can periodically (re)shape a profile of radiation attenuation (e.g., and alter an amount of radiation attenuated by the pre-object filter 500 (e.g., causing the unattenuated fan-angle to change as a function of which portion of the pre-object filter 500 is exposed to radiation)). Further, in one embodiment, the pre-object filter may be configured for translation in a direction substantially parallel to the fan-angle direction. By way of example, in some embodiments an object undergoing examination may be off-set relative to a center line of the support article, where the center line extends parallel to the axis of rotation. Accordingly, the pre-object filter may be translated in the fan-angle direction (e.g., moved left or right when looking into gantry bore) to correspond to the off-set such that a center line of the channel (e.g., extending parallel to the axis of rotation) is substantially matched to the off-set of the object (e.g., so that a center line of the patient aligns with a center line of the channel). Further, where a region-of-interest that is not positioned at an isocenter of the detector array, the pre-object filter 500 may be configured for motion in the fan-angle direction to follow the region-of-interest, for example. Movement or translations of the pre-object filter 500 may be controlled, for example, by a stepper motor or other motor, which may be controlled by a pre-object filter manipulator (e.g., 134 in FIG. 1), for example. In one embodiment, such a pre-object filter manipulator may be configured to receive information related to a rotating gantry (e.g., 104 in FIG. 1) and/or a support article (e.g., 112 in FIG. 1) from a controller (e.g., 132 in FIG. 1) to substantially synchronize translation of the pre-object filter 500 with the rotating gantry and/or support article, for example. Numerous modes for moving and/or translating the pre-object filter 500 are contemplated and a desired mode may be a function of, among other things, the intended application and/or desired functionality of the pre-object filter 500. For example, in a first mode, the pre-object filter 500 may be translated prior to and/or at a beginning of an imaging scan of an object such that a portion of the pre-object filter 500 that corresponds to a (e.g., cross-sectional) shape of the object is exposed to radiation (e.g., such that the unattenuated fan-angle more closely approximates a width of the object upon which radiation impinges). During the imaging scan, or the remaining portion of the imaging scan, the position of the pre-object filter 500 may or may not change as a function of the rotating gantry angle and/or the position/movement of the support article, for example. In a second mode, the pre-object filter 500 may be translated during the imaging scan based upon movement of the support article and/or rotation of the rotating gantry. In this way, the profile of the radiation attenuation is (e.g., periodically) re-shaped during the imaging scan and/or an amount of radiation attenuated in a fan-angle direction is adjusted during the imaging scan (e.g., the unattenuated fan-angle 308 is varied during the imaging scan). By way of example, an object (e.g., such as a human patient) may not be uniformly shaped. For example, a width of a patient's head is typically less than a width of the patient's shoulders. When an imaging scan involves imaging the patient's head and the patient's shoulders, it may be desirable to translate the pre-object filter 500 to cause a narrower portion of the channel 502 (e.g., proximate the second end 506) to be exposed to radiation when scanning the patient's head (e.g., to attenuate a greater amount of radiation in the fan-angle direction and to reduce an unattenuated fan-angle) and to cause a wider portion of the channel 502 (e.g., proximate the first end 504) to be exposed to radiation when scanning the patient's shoulders (e.g., to attenuate a smaller amount of radiation in the fan-angle direction and to increase an unattenuated fan-angle). Thus, the pre-object filter 500 may be translated so as to track a patient's size during the imaging scan. In a third mode, the pre-object filter 500 may be translated in a direction parallel to the axis of rotation (e.g., in the z-direction) during the imaging scan based upon a gantry angle of the rotating gantry to track, for example, changes in a size of an object from a front face, to a side face, to a rear face, and back to a side face. For example, typically, a human patient is wider when viewed from the front and back than when viewed from a side. As such, the pre-object filter 500 may translate during the rotation to cause less radiation to be attenuated when the radiation source is facing a front (e.g., at 0 degrees) or a back (e.g., at 180 degrees) of the patient than when facing a side (e.g., 90 or 270 degrees) of the patient. By way of example, a portion of the channel 502 having a larger width (e.g., proximate the first end 504) may be exposed to radiation or intervene between the patient and the radiation source when the gantry angle indicates that the radiation source is facing a front or back of a patient, and a portion of the channel 502 having a smaller width (e.g., proximate the second end 506) may be exposed to or intervene between the patient and the radiation source when the gantry angle indicates that the radiation source is facing a side of a patient. In this way, the profile of the radiation attenuation and unattenuated fan-angle may be (e.g., dynamically) altered during the rotation (e.g., as shown in FIG. 3) based upon the gantry angle, for example. Other modes for translating the pre-object filter 500 may include a combination of the modes described above, such as a combination of the second mode and the third mode. FIG. 6 illustrates another example pre-object filter 600 configured similarly to the pre-object filter 500 in FIG. 5, where a channel 602 extends in a direction parallel to the axis of rotation of a rotating gantry from a first end 604 to a second end 606 and is defined by a sidewall 608 of the pre-object filter 600. Whereas the sidewall 508 of the pre-object filter 500 is illustrated as meeting the top surface 510 abruptly at a substantially 90-degree angle, the sidewall 608 of pre-object filter 600 transitions more gradually or fluidly into the top surface 610 (e.g., as made visible by the lines drawn on the surface of the channel). It may be appreciated that such a difference may be a design preference and/or may be intended to soften a transition between heavily attenuated radiation traversing thick portions of the sidewall 608 and less attenuated radiation traversing the channel 602 and/or thinner portions of the sidewall 608. As illustrated in FIG. 5, a width of the channel 602 changes between the first end 604 and the second end 606 (e.g., such that the channel 602 narrows from the first end 604 to the second end 606). In this way, an amount of radiation attenuation in the fan-angle direction may be altered and/or a profile of radiation attenuation may be reshaped by translating the pre-object filter 600 in a direction substantially parallel to the channel 602, for example. FIG. 7 illustrates yet another example of a pre-object filter 700 configured to shape a profile of radiation attenuation in a fan-angle direction as a function of a profile of an object being examined. In this way, an amount of radiation attenuated in the fan-angle direction (e.g., x-direction) may be adjusted (e.g., altering an unattenuated fan-angle) based upon a shape of the object, before an imaging scan of an object is performed and/or during the imaging scan. Such a pre-object filter 700 may be comprised of aluminum, cooper, Teflon, and/or other materials that are at least partially opaque to radiation (e.g., and can thus attenuate a portion of the radiation directed toward the pre-object filter 500), for example. The pre-object filter 700 is configured for rotation about a filter axis extending in the fan-angle direction (e.g., the x-direction). Further, in one embodiment, the pre-object filter 700 may be configured for translation in the fan-angle direction to track a region of interest and/or to track an object that is offset from a center line of the support article, for example. A core 702 of the pre-object filter 700 is situated between a first end 704 and a second end 706 of the pre-object filter 700 and connects the first end 704 to the second end 706. The core 702 may comprise a parameter (e.g., circumference), measured at a mid-point between the first end 704 and the second end 706, that is smaller than a parameter (e.g., circumference) of the first end 704 and/or smaller than a parameter (e.g., circumference) of the second end 706. In this way, an aperture 708 (e.g., a valley) may be defined by the first end 704, the second end 706 and the core 702. That is, for example, an aperture 708 may be formed by the smaller parameter core 702 and the larger parameter first end 704 and/or second end 706. In one embodiment, such an aperture 708 may extend substantially 360 degrees about the pre-object filter 700. In the illustrated embodiment, a parameter (circumference) of the core 702 decreases gradually from the first end 704 and/or from the second end 706 toward a center of the core 702 (e.g., laying substantially midway between the first end 704 and the second end 706). In another embodiment, the parameter of the core 702 may decrease non-uniformly (e.g., in a stair-step fashion). As such, in another embodiment, an exposed sidewall of the core 702 may appear more jagged than the relatively smooth sidewall of the illustrated core 702. A width of the aperture 708 may differ between a first rotational angle of the pre-object filter 700 and a second rotational angle of the pre-object filter 700. As an example, the aperture 708 may measure a first width 710 at a first rotational angle (e.g., of 0 degrees) and may measure a second width 712 at a second rotational angle (e.g., at 90 degrees). In one embodiment, the widest portion of the aperture 708 is separated from the narrowest portion of the aperture 708 by approximately 90 degrees, and the width of the aperture 708 may continuously and/or incrementally decrease between the widest portion and the narrowest portion, for example. By way of example, the aperture 708 may be widest at the first rotational angle (e.g., which measures the first width 710) and may be narrowest at the second rotational angle (e.g., which measures the second width 712). The width the aperture 708 may gradually vary between various rotational angles, for example. Further, in one embodiment, the aperture 708 may gradually increase in width between the second rotational angle and a third rotational angle separated from the second rotational angle by 90 degrees (e.g., the third rotation angle may be at 180 degrees). At the third rotational angle, the width of the aperture 708 may be equal to the first width 710, for example. Further, between the third rotational angle and a fourth rotation angle separated from the third rotation angle by 90 degrees (e.g., the fourth rotation angle may be at 270 degrees), the aperture 708 may gradually decrease in width until, at the fourth rotation angle, the width of the aperture substantially equals the second width 712, for example. It can thus be appreciated that a first half of the pre-object filter 700 may be substantially symmetrical to a second half of the pre-object filter 700, such that the width of the aperture 708 at a given rotational angle substantially matches a width of the aperture 708 at another rotational angle 180 degrees from the given rotational angle, for example. FIGS. 8-9 illustrate cross-sections of the pre-object filter 700, and depict how a width of the aperture 708 changes at various rotation angles. More particularly, FIG. 8 illustrates a cross-sectional view 800 of the pre-object filter 700 taken along line 8-8 in FIG. 7, and FIG. 9 illustrates a cross-sectional view 900 of the pre-object filter 700 taken along line 9-9 in FIG. 7. Thus, FIG. 8 may illustrate a cross-sectional view 800 depicting a plane of the pre-object filter 700 at the first and third rotational angles (e.g., where the aperture 708 is widest), and FIG. 9 may illustrates a cross-sectional view 900 depicting a plane of the pre-object filter at the second and fourth rotational angles (e.g., where the aperture 708 is narrowest). A tube 802 or central core about which the pre-object filter 700 is configured to rotate may extend through a center 714 of the pre-object filter 700 in a direction parallel to the filter axis and/or perpendicular to an axis of rotation for a rotating gantry of a CT system, for example (e.g., the tube 802 may extend in the x-direction). In one embodiment, such a tube 802 or central core may be hollow and/or may comprise one or more low attenuation materials having structural integrity to support the pre-object filter. Surrounding the tube 802 may be the core 702, which may comprise radiation attenuating material(s), such as copper, aluminum, Teflon and/or other materials configured to attenuate at least a portion of the radiation contacting the pre-object filter 700. Such radiation attenuating material may be shaped to form an aperture 708 having a desired width(s). For example, as illustrated in the cross-sectional view 800 (e.g., taken along line 8-8 in FIG. 7), the aperture 708 measures a first width 710 at a first rotational angle (e.g., 0 degrees) and a third rotational angle (e.g., 180 degrees). As illustrated in the cross-sectional view 900 (e.g., taken along line 9-9 in FIG. 7), at the second rotational angle (e.g., 90 degrees) and the fourth rotational angle (e.g., 270 degrees), the aperture 708 measures a second width 712, different than the first width 710. It may be appreciated that a maximum depth of the aperture 708 (e.g., measured in the y-direction) in FIGS. 8-9 may be substantially equal at all or substantially all of the rotational angles, even though a profile of the aperture 708 changes at different rotational angles. The pre-object filter 700 is configured for rotation by the tube 802 about the filter axis, which is substantially parallel to the fan-angle direction. For example, in the illustrated embodiment, the filter axis may extend in the x-direction. In one embodiment, the pre-object filter 700 may also be configured for movement in the fan-angle direction. Movement of the pre-object filter 700 may be controlled by a stepper motor or other motor, which may be controlled by a pre-object filter manipulator (e.g., 134 in FIG. 1), for example. Numerous modes for at least partially rotating the pre-object filter 700 about the filter axis are contemplated and may be a function of, among other things, the intended application and/or desired functionality of the pre-object filter 700. For example, in one embodiment, where the pre-object filter 700 is substantially symmetrically shaped (e.g., where a first half of the filter extending from a midpoint of the core to the first end 704 is shaped similarly to a second half of the filter extending form the midpoint of the core to the second end 706)), the pre-object filter 700 may be configured to rotate substantially synchronously with the rotating gantry (e.g., the pre-object filter 700 and the rotating gantry may rotate at a same speed). When the rotating gantry is at 0 degrees (e.g., as shown in FIG. 3), the pre-object filter 700 may be configured such that the first rotational angle of the pre-object filter 700 may be facing the object (e.g., as illustrated in FIG. 8), causing a first amount (e.g., a minimum amount) of radiation to be attenuated by the pre-object filter 700 and thus causing the unattenuated fan-angle have a first value). As the rotating gantry rotates about the object, the pre-object filter 700 may be synchronously rotated about the filter axis. Thus, when the rotating gantry is at 90 degrees at illustrated in FIG. 4, the second rotational angle of the pre-object filter 700 may be facing the object (e.g., as illustrated in FIG. 9), causing a second amount (e.g., a maximum amount) of radiation to be attenuated by the pre-object filter 700 and thus causing the unattenuated fan-angle to have a second value (e.g., which is less than the first value)). If the pre-object filter 700 is substantially symmetric, as the rotating gantry continues to rotate away from 90 degrees, the pre-object filter 700 may continue to adjust an amount of radiation attenuation to correspond to a profile of the object (e.g., increasing an unattenuated fan-angle until 180 degrees and then decreasing the unattenuated fan-angle until 270 degrees). In this way, the profile of radiation attenuation may be substantially continuously re-shaped as the rotating gantry rotates about the object, for example. In other modes, the pre-object filter 700 may not rotate synchronously with the rotating gantry and/or the pre-object filter 700 may be configured to oscillate between two or more rotational angles of the pre-object filter 700, for example. Moreover, in yet another mode, the pre-object filter 700 may be configured to rotate to a specified rotational angle prior to and/or at a beginning of an examination of an object and may remain stationary during the remaining portion of the examination. For example, a pre-scan may be performed to determine a profile of the object and the pre-object filter 700 may be rotated about the filter axis to an angle that corresponds to the profile (e.g., and that causes radiation having a trajectory that contacts the object to be attenuated less than radiation having a trajectory that does not contact the object). In this way, in this mode, a profile of radiation attenuation may be re-shaped and/or an amount of radiation attenuation may be adjusted between examinations of various objects (e.g., or between examinations of a same object), but may not be re-shaped/adjusted during an examination of an object, for example. FIGS. 10 and 11 illustrate views of yet another pre-object filter 1000 configured to shape a profile of radiation attenuation in a fan-angle direction as a function of a profile of an object being examined. In this way, an amount of radiation attenuated in the fan-angle direction (e.g., the x-direction) may be adjusted (e.g., altering an unattenuated fan-angle), before an imaging scan of an object is performed and/or during the imaging scan, based upon a shape, or profile, of the object, for example. Such a pre-object filter 1000 may be comprised of aluminum, cooper, Teflon, and/or other materials that are at least partially opaque to radiation, for example. In another embodiment, at least a portion of the pre-object filter 1000 may be comprised of a radiation transparent material(s). The pre-object filter 1000 is configured for oscillation (e.g., partial rotation) about a filter axis extending in a direction (e.g., the x-direction) substantially perpendicular to the axis of rotation for a rotating gantry and/or substantially perpendicular to a trajectory of radiation emitted from a radiation source (e.g., which typically follows the y-direction). For example, in one embodiment, the pre-object filter 1000 may be configured to oscillate by about 60 degrees (e.g., between negative 30 degrees and positive 30 degrees as labeled on the pre-object filter 1000). Further, in one embodiment, the pre-object filter 1000 may be configured for translation in the fan-angle direction to track a region of interest and/or to track an object that is offset from a center line of the support article, for example. The pre-object filter 1000 may comprise a bore 1002 through which a tube or a hollow core (e.g., 802 in FIG. 8) configured to rotate the pre-object filter 1000 may be inserted. In another embodiment, the pre-object filter 1000 may be machined with one or more flanges, for example, to replace the bore 1002, and a motor may be configured to connect to the flanges to oscillate the pre-object filter 1000, for example. Other manners and/or mechanisms for oscillating the pre-object filter 1000 are also contemplated. A first surface 1004 of the pre-object filter 1000 is comprised of two inwardly sloping sidewalls 1006 and 1008 (e.g., sloping inward from an outside edge to a location proximate the bore 1002) that meet at a location proximate the bore 1002 at an angle 1010 other than 180 degrees (e.g., in one embodiment, 1010, it may be desirable for the angle 1010 to be small to reduce variability of the radiation in a cone-angle during the oscillation of the pre-object filter 1000). For example, in the illustrated embodiment, a first inwardly sloping sidewall 1006 and a second inwardly sloping sidewall 1008 join to form an angle 1010 of approximately 100 degrees. In another embodiment, the angle 1010 may be a different obtuse angle, a right angle, or an acute angle, for example. Moreover, in an embodiment, a second surface 1012, diametrically opposite the first surface 1004 relative to the bore 1002, is substantially symmetrical to the first surface 1004 (e.g., such that the second surface 1012 is approximately a mirror image of the first surface 1004), for example. A top surface 1014 and a bottom surface 1016 of the example pre-object filter 1000 are curved outward from the bore 1002 when viewed from a cross-section depicting a first end 1018 or a second end 1020 (e.g., where the second end 1020 is diametrically opposed to the first end 1018 relative to an aperture 1022 formed between the first end 1018 and the second end 1020). The pre-object filter 1000 is shaped such that the aperture 1022 is formed between the first end 1018 and the second end 1020 and extends in a direction parallel to the filter axis (e.g., parallel to the x-direction). The aperture 1022 may slope 1024 inward from the first end 1018 and/or the second end 1020 to a center region (e.g., not shown) between the first end 1018 and the second end 1020. Thus, a depth of the aperture 1022 (e.g., measured in the y-direction from the top surface 1014) may be greater proximate the center region of the pre-object filter 1000 than at a location proximate the first end 1018 and/or the second end 1020. Moreover, the aperture 1022 may slope 1026 inward from the first surface 1004 and/or the second surface 1012 to a center region between the first surface 1004 and the second surface 1012. Thus, the aperture 1022 may slope inward toward a center region in both the x-direction and in the z-direction, for example. A channel 1028 may further extend across the pre-object filter 1000 in a direction substantially parallel to the axis of rotation (e.g., the z-direction) for a rotating gantry (e.g., the channel 1028 may extend in the z-direction) between the first surface 1004 and the second surface 1012 and may, in an example, have substantially uniform depth (e.g., measured in the y-direction from a top surface 1014) when moving from the first surface 1004 and the second surface 1012 or vice versa, for example. Although, the depth may change slightly due to changes in the curvature of the top surface 1014, for example. FIG. 11 illustrates a top down view of the pre-object filter 1000 further illustrating how the aperture 1022 slopes inward toward a center region (e.g., proximate the channel 1028) from the first end 1018, the second end 1020, the first surface 1004, and/or the second surface 1012. FIG. 11 further illustrates the channel 1028 extending in a direction substantially parallel to the axis of rotation (e.g., the z-direction) and having a substantially uniform depth in the y-dimension, in an example. In may be appreciated that as illustrated in FIGS. 10 and 11, the aperture 1022 has an increased width (e.g., measured in the x-direction) at 0 degrees, and decreases in width from 0 degrees toward the first surface 1004 and/or the second surface 1012 (e.g., at plus and/or minus 30 degrees). Such changes in width may provide for shaping (or reshaping) the profile of radiation attenuation as a function of a profile of an object during an imaging scan and/or between imaging scans, for example. That is, the portion of pre-object filter 1000 exposed to radiation or upon which radiation impinges may change by rotating or oscillating the pre-object filter, causing changes in a profile of radiation attenuation and/or causing an amount of radiation attenuated to vary. By way of example, as illustrated in FIG. 12, a first cross-sectional slice 1200 (e.g., taking along line 12-12 in FIG. 10) may be exposed to radiation when the pre-object filter 1000 is rotated to negative 30 degrees (e.g., causing the radiation source to face the −30 degree mark in FIGS. 10 and 11). The first cross-sectional slice 1200 forms an aperture 1202 having a first width 1204 (e.g., which is approximately equal to the width of the channel 1028 illustrated in FIGS. 10 and 11). As illustrated in FIG. 13, a second cross-sectional slice 1300 (e.g., taking along line 13-13 in FIG. 10), different than the first cross-sectional slice, may be exposed to radiation when the pre-object filter 1000 is rotated to 0 degrees (e.g., causing the radiation source to face the 0 degree mark in FIGS. 10 and 11). The second cross-sectional slice 1300 forms an aperture 1302 having a second width 1304, which is different than (e.g., greater than) the first width 1204 of the aperture 1202. As such, an amount of radiation attenuated when the pre-object filter 1000 is rotated to negative 30 degrees may be different than an amount of radiation attenuated when the pre-object filter 1000 is rotated to 0 degrees. For example, given that the width of the aperture is greater at 0 degrees than at negative 30 degrees, more radiation may be attenuated at negative 30 degrees than at 0 degrees. Thus, the unattenuated fan-angle when the pre-object filter 1000 is rotated to negative 30 degrees may be less than the unattenuated fan-angle when the pre-object filter is rotated to zero degree. Moreover, as illustrated in FIG. 11, the width of the aperture 1022 may increase from negative 30 degrees to 0 degrees, and thus the unattenuated fan-angle may (e.g., gradually) increase and the amount of radiation attenuated may (e.g., gradually) decrease as the pre-object filter 1000 is rotated from negative 30 degrees to 0 degrees. It may be appreciated that a maximum depth of the aperture 1202 in FIG. 12 and a maximum depth of the aperture 1302 in FIG. 13 (e.g., measured in the y-direction) is typically substantially equal (e.g., and measure a depth of the channel 1028 in FIG. 11). Although not shown, a cross-sectional slice exposed to radiation when the pre-object filter 1000 is rotated to 30 degrees may be substantially similar to the cross-sectional slice illustrated in FIG. 12. Thus, the amount of radiation attenuated may decrease at sequential rotational angles of the pre-object filter 1000 as the pre-object filter is rotated from negative 30 degrees to 0 degrees and may increase at sequential rotational angles of the pre-object filter 1000 as the pre-object filter is rotated from 0 degrees to 30 degrees, for example. The pre-object filter 1000 is configured for partial rotation (e.g., or oscillation) about the filter axis, which is substantially perpendicular to an axis of rotation for a rotating gantry of a CT system. For example, the axis of rotation of the gantry may extend in the z-direction and the filter axis may extend in the x-direction. It may be appreciated that the degree of rotation may depend upon an angle 1010 formed by the joining of the first inwardly sloping sidewall 1006 and the second inwardly sloping sidewall 1008, as it may be desirable for radiation to traverse both a bottom portion of the pre-object filter (e.g., below the bore 1002 in FIG. 10) and a top portion (e.g., above the bore 1002 in FIG. 10). Movement of the pre-object filter 1000 may be controlled by a stepper motor or other motor, which may be controlled by a pre-object filter manipulator (e.g., 134 in FIG. 1), for example. Numerous modes for at least partially rotating the pre-object filter 1000 about the filter axis are contemplated and may be a function of, among other things, the intended application and/or desired functionality of the pre-object filter 1000. For example, the pre-object filter 700 may be configured to oscillate between negative 30 degrees and 30 degrees during a rotation of the rotating gantry. By way of example, when the rotating gantry is at 0 degrees (e.g., as shown in FIG. 3), the pre-object filter 1000 may be configured such that a first rotational angle (e.g., 0 degrees) of the pre-object filter 1000 may be facing the radiation source (e.g., causing a first amount (e.g., a minimum amount) of radiation to be attenuated by the pre-object filter 1000 and thus causing the unattenuated fan-angle have a first value). As the rotating gantry rotates from 0 degrees to 90 degrees (e.g., as illustrated in FIG. 4), the pre-object filter 1000 may be rotated from the first rotational angle to a second rotational angle (e.g., 30 degrees) (e.g., causing a second amount (e.g., a maximum amount) of radiation to be attenuated by the pre-object filter 1000 and thus causing the unattenuated fan-angle to have a second value (e.g., which is less than the first value)). As the rotating gantry rotates from 90 degrees to 180 degrees, the pre-object filter 1000 may be rotated from the second rotational angle back to the first rotational angle (e.g., 0 degrees). Further, as the rotating gantry rotates from 180 degrees to 270 degrees, the pre-object filter 1000 may be rotated from the first rotational angle to a third rotational angle (e.g., negative 30 degrees). In this way, the pre-object filter 1000 is oscillated as a function of a gantry rotation angle, for example, and the profile of radiation attenuation is substantially continuously re-shaped as the rotating gantry rotates about the object, for example. Moreover, in yet another mode, the pre-object filter 1000 may be configured to rotate to a specified rotational angle prior to and/or at a beginning of an examination of an object and may remain stationary during the remaining portion of the examination. For example, a pre-scan may be performed to determine a profile of the object and the pre-object filter 1000 may be rotated about the filter axis to an angle that corresponds to the profile (e.g., or to a largest dimension of the object being scanned). In this way, in this mode, a profile of radiation attenuation may be re-shaped and/or an amount of radiation attenuation may be adjusted between examinations of various objects (e.g., or between examinations of a same object), but may not be re-shaped/adjusted during an examination of an object, for example. It may be appreciated that the foregoing pre-object filters are merely provided as example configurations of pre-object filters that may be utilized to shape a profile of radiation attenuation as a function of a profile of an object and are not intended to limit the scope of the instant disclosure, including the scope of the claims. Moreover, it may be appreciated that the illustrated pre-object filters may comprise readily apparent features which are not described. FIG. 14 illustrates an example pre-object filter manipulator 1400 (e.g., 134 in FIG. 1) configured to control motion (e.g., translation and/or rotation) of a pre-object filter (e.g., such as one or more of the foregoing pre-object filters) as a function of, among other things, a profile of an object undergoing an examination, a gantry rotation angle of the rotating gantry, and/or a translation coordinate and speed of the object (e.g., as indicated by movement of a support article supporting the object). The example pre-object filter manipulator 1400 comprises, among other things, an object profile generator 1402, a controller interface component 1404, and a filter controller 1406. The object profile generator 1402 is configured to create a profile of the object based upon information provided by a source such as, for example, a user (e.g., which may provide one or more measurements of the object) and/or a pre-scan (e.g., also referred to as a scout scan) of the object. Such a pre-scan may comprise performing an initial (e.g., low-dose) examination using a CT system and/or performing an examination using a line scanner at an entrance of the CT scanner, for example. Pre-scan information generated from such a pre-scan may be provided to the object profile generator 1402 via a terminal and/or a controller, for example. Typically, the pre-scan information is insufficient to reconstruct an image of the object. However, using such information, the object profile generator may determine a relative orientation of a support article and the object, one or more measurements (e.g., dimensions) of the object, etc., from which to create the profile of the object. Thus, using pre-scan information and/or user input, for example, the object profile generator 1402 may create a profile of the object. The controller interface component 1404 may be configured to interface with a controller (e.g., 132 in FIG. 1) and to receive information related to an examination unit (e.g., 108 in FIG. 1) which may assist in determining when and/or how to rotate and/or translate the pre-object filter. For example, the controller interface component 1404 may receive information indicative of a rotation speed of a rotating gantry (e.g., 104 in FIG. 4) and/or a gantry rotational angle of the rotating gantry. As another example, the controller interface component 1404 may receive information indicative of a translation coordinate of a support article configured to support the object (e.g., to determine which aspect/cross-section of the object is presently being exposed to radiation). The profile of the object created by the object profile generator 1402 and/or information from the controller interface component 1404 may be received by the filter controller 1406 configured to manipulate the pre-object filter to shape the profile of radiation attenuation in the fan-angle direction. For example, as previously described, a shape of a profile may be changed based upon a profile of the object, a gantry rotational angle, and/or a position of the support article, for example. Thus, the filter controller 1406 may be configured to manipulate (e.g., or generate manipulation instructions) for controlling how the pre-object filter is to be moved to shape a profile of radiation attenuation, for example. FIG. 15 illustrates an example method 1500 for imaging a patient and/or object, such as via a computed tomography (CT) system or other imaging system. The example method 1500 begins at act 1502, and a profile of the patient is acquired at act 1504. The profile describes one or more features of the patient, such as a shape, size (e.g., measurements), and/or orientation relative to a support article supporting the patient. Such a profile may be acquired manually and/or automatically. For example, measurements corresponding to a size of the patient may be input by a user and/or a pre-scan may be performed to determine shape, size, and/or orientation information from which an object profile may be developed. At act 1506 in the example method, an imaging scan is performed on the patient. The imaging scan typically involves exposing the patient to a sufficient dose from which an image of a desired quality may be produced. During the imaging scan, the patient is exposed to radiation, some of which traverse the patient. Information yielded from the radiation that traversed the patient may be utilized to generate/reconstruct an image(s). Such an image may be a two-dimensional image, a three-dimensional image, a four dimensional image, etc. Moreover, the imaging scan may involve viewing the patient from a single angle (e.g., such as in projection scanning), viewing the patient from a multitude of angle (e.g., such as in tomosynthesis scanning), and/or viewing the patient from at least 180 degrees (e.g., such as in CT scanning). At act 1508 in the example method 1500, a profile of radiation attenuation in a fan-angle direction is shaped as a function of the profile of the patient to affect an amount of radiation attenuated in a fan-angle direction. As previously described, the shaping may occur at least one of prior to performing the imaging scan and/or during the imaging scan is a function of the profile of the patient. Thus, a profile of radiation attenuation for a first patient may be different than a profile of the radiation attenuation for a second patient and/or the profile of attenuation may change during a rotation (e.g., to change as (e.g., cross-sectional) size of the patient as viewed from various angles changes). To shape the profile of the radiation attenuation, one or more of the foregoing techniques (e.g., modes) and/or pre-object filters may be utilized. For example, in one embodiment, shaping the profile of radiation attenuation may comprise translating the pre-object filter in a direction parallel to an axis of rotation for a rotating gantry of an imaging system configured to perform the imaging scan and/or parallel to the z-direction (e.g., as described with respect to FIGS. 5-6). In another embodiment, shaping the profile of radiation attenuation may comprise rotating and/or oscillating the pre-object filter about a filter axis that is parallel to the x-direction, for example (e.g., such as described with respect to FIGS. 7-13). By way of example, in one embodiment, the pre-object filter may be oscillated between a first position and a second position (e.g., separated by less than a specified amount, such as by less than 60 degrees, for example). In another embodiment, the pre-object filter may be configured for complete rotation about the filter axis and may, in one embodiment, be synchronized with the rotation of the rotating gantry, for example. The example method 1500 ends at act 1510. Still another embodiment involves a computer-readable medium comprising processor-executable instructions configured to implement one or more of the techniques presented herein. An example computer-readable medium that may be devised in these ways is illustrated in FIG. 16, wherein the implementation 1600 comprises a computer-readable medium 1602 (e.g., a CD-R, DVD-R, or a platter of a hard disk drive), on which is encoded processor-executable instructions 1604. This computer-readable data 1604 in turn comprises a set of computer instructions 1606 configured to operate according to one or more of the principles set forth herein. In one such implementation 1600, the processor-executable instructions 1604 may be configured to perform a method 1608, such as at least some of the example method 1500 of FIG. 15. In another such embodiment, the processor-executable instructions 1604 may be configured to implement a system, such as at least some of the example environment 100 of FIG. 1 and/or at least some of example pre-object filter manipulator 1400, for example. Many such computer-readable media may be devised by those of ordinary skill in the art that are configured to operate in accordance with one or more of the techniques presented herein. Moreover, “exemplary” is used herein to mean serving as an example, instance, illustration, etc., and not necessarily as advantageous. As used in this disclosure, “or” is intended to mean an inclusive “or” rather than an exclusive “or.” In addition, “a” and “an” as used in this disclosure are generally be construed to mean “one or more” unless specified otherwise or clear from context to be directed to a singular form. Also, at least one of A and B and/or the like generally means A or B or both A and B. Furthermore, to the extent that “includes,” “having,” “has,” “with,” or variants thereof are used in either the detailed description or the claims, such terms are intended to be inclusive in a manner similar to the term “comprising.” Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims. As used in this disclosure, “component,” “module,” “system,” “interface,” and the like are generally intended to refer to a computer-related entity, either hardware, a combination of hardware and software, software, or software in execution. For example, a component may be, but is not limited to being, a process running on a processor, a processor, an object, an executable, a thread of execution, a program, and/or a computer. By way of illustration, both an application running on a controller and the controller can be a component. One or more components may reside within a process and/or thread of execution and a component may be localized on one computer and/or distributed between two or more computers. Furthermore, the claimed subject matter may be implemented as a method, apparatus, or article of manufacture using standard programming and/or engineering techniques to produce software, firmware, hardware, or any combination thereof to control a computer to implement the disclosed subject matter. The term “article of manufacture” as used herein is intended to encompass a computer program accessible from any computer-readable device, carrier, or media. Of course, those skilled in the art will recognize many modifications may be made to this configuration without departing from the scope or spirit of the claimed subject matter. Further, unless specified otherwise, “first,” “second,” and/or the like are not intended to imply a temporal aspect, a spatial aspect, an ordering, etc. Rather, such terms are merely used as identifiers, names, etc., for features, elements, items, etc. (e.g., “a first channel and a second channel” generally corresponds to “channel A and channel B” or two different (or identical) channels). Although the disclosure has been shown and described with respect to one or more implementations, equivalent alterations and modifications will occur to others skilled in the art based upon a reading and understanding of this specification and the annexed drawings. The disclosure includes all such modifications and alterations and is limited only by the scope of the following claims. In particular regard to the various functions performed by the above described components (e.g., elements, resources, etc.), the terms used to describe such components are intended to correspond, unless otherwise indicated, to any component which performs the specified function of the described component (e.g., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated example implementations of the disclosure. Similarly, illustrated ordering(s) of acts is not meant to be limiting, such that different orderings comprising the same of different (e.g., numbers) of acts are intended to fall within the scope of the instant disclosure. In addition, while a particular feature of the disclosure may have been disclosed with respect to only one of several implementations, such feature may be combined with one or more other features of the other implementations as may be desired and advantageous for any given or particular application.
	description	This application is a division of, and claims priority under § 120 to, application Ser. No. 14/867,936 filed Sep. 28, 2015, now U.S. Pat. No. 10,553,322. This parent application is incorporated by reference herein in its entirety. FIG. 1 is a cross-section of a related art Passive Containment Cooling System (PCCS) 10, such as a PCCS 10 useable in an ESBWR or other type of nuclear power plant. For example, PCCS 10 may be submerged in a coolant source like a PCCS pool inside or near a nuclear reactor containment building. As shown in FIG. 1, PCCS 10 may include an inlet 15 that receives steam, heated water, noncombustible gasses, and/or other energetic fluids that may accumulate in a nuclear reactor containment or other power production environment. For example, inlet 15 may include an opening into a nuclear power plant containment that receives such fluids and delivers the fluids to related art PCCS 10. Inlet 15 flows into an upper manifold 11, which may be a large, voided drum or other fluid-receiving structure. One or more end plates 19 may be bolted to upper manifold 11 to close ends of upper manifold 11 for fluid containment. Upper manifold 11, in turn, connects to several vertical PCCS tubes 12 below upper manifold 11. Fluid may be distributed in manifold 11 and flow into PCCS tubes 12, under gravity and/or energy from inlet 15. Because PCCS tubes 12 may be submerged in a coolant, like chilled water, the increased surface area of PCCS tubes 12 may cool and/or condense fluid received into PCCS 10. Such cooling and condensation in PCCS tubes 12 may further drive the fluid downward into lower manifold 13. Condensed liquid collecting down into lower manifold 13 may flow out through an outlet 14 of PCCS 10. Additional details of related art PCCS structures are described in co-owned US Patent Publication 2015/0146839 to Marquino et al., the entirety of which is incorporated herein by reference in its entirety. Example embodiments include systems to control fluid flow in a flow path of an open or closed volume. Example systems use several swappable plates that can be positioned at desired sequences or intervals in the flow. The plates have varying surfaces that interact with and/or direct the flow in desired ways. A retainer holds the various plates in position, achieving the desired flow. For example, plates may mate with a retaining edge extending a length of the flow volume, and plates may be a width of the flow volume, such that when the length of the retaining edge is filled with the plates, the entire flow area may be filled. Plates can present a variety of geometries, including perforations, labyrinthine passages, chevrons, voids, mixing tabs, swirl vanes, and solid, flat planes to enhance, impede, make turbulent, mix, direct, and/or change fluid flow. Plates can be placed in positions in the volume based on their geometries and effect on flow to achieve desired flows. For example, a chevron plate may be placed directly below an inlet for a high-velocity and high-temperature steam and non-condensable gas mixture in a PCCS upper manifold, and the chevron plate may deflect and redirect the flow to diffuse it along an entire length of the upper manifold. Example methods include installing modular fluid flow control systems in areas subject to fluid flow. Different plates can be placed at different positions within the volume to achieve desired flow. For example, a plate with a chevron and a plate with several perforations may be slid into a retaining edge that allows single-dimensional movement of the plates until the volume is full. The retainer to hold the plates may be separately installed in the volume or may already be present. In example methods plates may be swapped, removed, or added because they are modular, in order to achieve desired flow characteristics. Because this is a patent document, general broad rules of construction should be applied when reading and understanding it. Everything described and shown in this document is an example of subject matter falling within the scope of the appended claims. Any specific structural and functional details disclosed herein are merely for purposes of describing how to make and use example embodiments or methods. Several different embodiments not specifically disclosed herein fall within the claim scope; as such, the claims may be embodied in many alternate forms and should not be construed as limited to only example embodiments set forth herein. It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. It will be understood that when an element is referred to as being “connected,” “coupled,” “mated,” “attached,” or “fixed” to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between”, “adjacent” versus “directly adjacent”, etc.). Similarly, a term such as “communicatively connected” includes all variations of information exchange routes between two devices, including intermediary devices, networks, etc., connected wirelessly or not. As used herein, the singular forms “a”, “an” and “the” are intended to include both the singular and plural forms, unless the language explicitly indicates otherwise with words like “only,” “single,” and/or “one.” It will be further understood that the terms “comprises”, “comprising,”, “includes” and/or “including”, when used herein, specify the presence of stated features, steps, operations, elements, ideas, and/or components, but do not themselves preclude the presence or addition of one or more other features, steps, operations, elements, components, ideas, and/or groups thereof. It should also be noted that the structures and operations discussed below may occur out of the order described and/or noted in the figures. For example, two operations and/or figures shown in succession may in fact be executed concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved. Similarly, individual operations within example methods described below may be executed repetitively, individually or sequentially, so as to provide looping or other series of operations aside from the single operations described below. It should be presumed that any embodiment having features and functionality described below, in any workable combination, falls within the scope of example embodiments. The Inventors have newly recognized that highly energetic fluids, such as saturated steam, combustibles, and super-heated non-condensable gasses, may produce uneven flow distribution in typical PCCS systems when produced in a power plant. For example, during a transient involving a loss of coolant, superheated containment, or other event with highly energetic fluid flows, such fluids may enter a PCCS system 10 (FIG. 1) though an inlet 15 (FIG. 1). Due to the energy of these fluid flows, upper manifold 11 (FIG. 1) may be unable to evenly disperse or diffuse the energetic flow across all PCCS tubes 12 (FIG. 1), thereby reducing the overall efficiency of the PCCS system 10 (FIG. 1). The Inventors have further recognized that fluid flow generally, such as in manifolds as well as pipes, vents, drains, etc., may be difficult to easily manage based on different encountered flows. For example, it may be desirable to evenly-distribute a heated flow through a heat exchanger, or it may be desirable to limit flows around sensitive components or change internal flow characteristics for expected destructive flows. However, fluid flow structures are typically statically constructed with simple binary flow on/off controls without finer, easily-implemented control over internal flow characteristics. Example embodiments described below address these and other problems recognized by the Inventors with unique solutions enabled by example embodiments. The present invention is systems and methods for modularly adjusting fluid flow through an area. In contrast to the present invention, the small number of example embodiments and example methods discussed below illustrate just a subset of the variety of different configurations that can be used as and/or in connection with the present invention. FIG. 2 is an illustration of a PCCS upper manifold 11 modified in accordance with an example system and method. As shown in FIG. 3, manifold 11 includes a retainer to hold an example embodiment diverter. For example, a notched or grooved ledge 100 may be affixed to or formed on an inner surface of upper manifold 11. Grooved ledge 100 may run an entire length of upper manifold 11 or may be partial or discontinuous. Multiple grooved ledges 100 may be used in example embodiments; for example, two opposite grooved ledges 100, as shown in FIG. 2, may be on opposite inner surfaces of upper manifold 11 so as to face one another with grooves opening toward one another. Grooved ledges 100 may be rigid and fabricated of materials known to maintain their physical properties in a nuclear reactor environment. Example methods may create retaining structures like grooved ledge 100 through installation or at initial creation of upper manifold 11. For example, grooved ledges 100 may be installed by welding or bolting during a plant outage or other maintenance period when operators have access to upper manifold 11. Or, for example, grooved ledge 100 may be integrally formed during the casting and/or shaping of upper manifold 11 so as to always be present in PCCS upper manifold 11. Although shown installed in an upper manifold 11 of a PCCS system, it is understood that grooved ledge 100 used in connection with example embodiments may be installed in other fluid passages, like pipes or vents. FIG. 3 is an illustration of an example embodiment fluid diverter system 200. As shown in FIG. 3, fluid diverter system 200 includes one or more modular plates configured to be retained in a retainer of example methods. For example, fluid diverter system 200 may include several plates all having a tongued-edge 210 that matches and mates with grooved ledge 100 (FIG. 2) on both sides of the plates. In this way, example embodiment fluid diverter system 200 may slide between and be retained by grooved ledge 100 (FIG. 2). Of course, other retaining structures may be used, including dovetails, mechanical interlocks, zippers, magnetized surfaces, locking pieces, etc., to join example embodiment system 200 with a desired flow space, such as upper manifold 11 (FIG. 2). Similarly, while example system 200 may use a sliding structure to allow single-dimensional movement of modular plates that are locked in place by adjacent plates and/or interior surfaces, it is understood that other loading structures, like grooves, ratchets, chains, springs, adhesives, tangs-and-slots, etc. may be used to selectively move and retain plates in desired positions with respect to fluid flow. Example embodiment fluid diverter system 200 may include different types of plates to selectively manage flow where system 200 is employed. For example, example embodiment system may be installed such that largest surfaces of system 200 are perpendicular throughout a fluid flow through a volume, requiring fluid flow substantially interact with system 200. Alternately, example embodiment fluid diverter system 200 may be angled or placed at any other orientation with respect to expected fluid flow. Various plates may be installed and retained in example embodiment system 200 at expected positions and orientations of fluid flow to control the fluid flow in any desired manner. For example, as shown in FIG. 3, example embodiment flow diverter system 200 may include a chevron plate 201 with oppositely-wedged or curved surfaces 211. Chevron plate 201 may divide and/or redirect an energetic flow encountering opposite surfaces 211 in order to redistribute or separate fluid flows. Example system 200 may similarly include a blocking plate 203, which is substantially solid and blocks relatively all flow therethrough. As fluid encounters solid plate 203 perpendicular to flow, such flow may be stopped; similarly, where solid plate 203 is encountered at an angle, such flow may become angled as well. Example system 200 may include a perforated plate 204 that includes one or more holes 214 positioned and dimensioned to allow only a desired amount or location of fluid flow through perforated plate 204. Sufficiently small holes 214 may further limit fluid flow through frictional forces as well as reduced flow area, and holes 214 may be specifically positioned, such as at an edge or in a gradient, to control and shape fluid flow through perforated plate 203. Example embodiment system 200 may also include a voided plate or separator plate 202 that minimally obstructs flows while separating or positioning adjacent plates. For example, separator plate 202 may contain 95% or more open flow area, while perforated plate 204 may have less than 95% open flow area created by holes 214. Because plates 201, 202, 203, and 204 may all have similar widths terminating at tongued edges 210 that mate into a retainer in a flow passage, any of plates 201, 202, 203, and 204 may equally fit in a same flow passage, such as by being slid lengthwise into a same grooved edge 100 (FIG. 2). That is, plates 201, 202, 203, and 204 may be modular within example systems. As shown in FIG. 3, plates 201, 202, 203, and 204 may directly abut one another at length ends of each plate when installed. Further, plates 201, 202, 203, and/or 204 may interlock or become removably joined in the length dimension by use of magnets, adhesives, locking joints, fasteners, etc. to prevent fluid flow from significantly escaping between plates. Plates 201, 202, 203, and/or 204 may be mixed and matched along a length of example system 200 when installed in a flow path. That is, any of plates 201, 202, 203, and 204 may be selected for a particular length position to achieve desired fluid flow at that position. As shown in FIG. 3, for example, perforated plates 204 may be positioned at length ends of example system 200, separated by separator plates 202. Depending on sizing and numerosity of holes 214 as well as widths of separator plates 202, fluid may flow relatively easily through length ends of example embodiment system 200. Chevron plate 201 and/or solid plates 203 may occupy more central locations, which may both divert and block fluid from flowing through central length portions of example embodiment flow diverter system 200. Of course, other arrangements with different numbers, orders, and individual characteristics of plate(s) are useable in example systems outside of the sequence shown in FIG. 3. FIG. 4 is an illustration of an example embodiment flow diverter system 200 as installed in an upper manifold 11 of a PCCS system. In example methods, end plates 19 of PCCS upper manifold 11 may be removed during a maintenance or outage period, allowing access to an interior of upper manifold 11. One or more plates of example system 200 may be installed in retainers in manifold 11 while end plate 19 is removed. For example, plates may be slid in grooved ledges 100 at either side of manifold 11 as shown in FIG. 2 via tongued edges 210. When a desired number and sequence of plates are installed, end plate 19 may be reaffixed to manifold 11, sealing the same. As shown in FIG. 4, in one example embodiment, chevron plate 201 may be positioned directly below inlet 15 of a PCCS system. In this way, energetic flows of saturated steam and/or non-condensable or noncombustible gasses from inlet 15 may be diverted by chevron plate 201 along a length of example embodiment system and thus upper manifold 11. One or more blocking plates 203 directly at both sides of chevron plate 201 may further enhance the diversion and/or diffusion of the energetic flow along a length of upper manifold 11. Then perforated plates 204 and separator plates 202 may be positioned at lengthwise ends of example embodiment system 200. Perforated plates 204 and separator plates 202 may permit substantially more fluid flow into PCCS tubes 12 directly vertically below perforated plates 204 and separator plates 202. All plates in example embodiment flow diverter system 200 may directly abut in a lengthwise arrangement and occupy substantially all flow path through manifold 11. All plates may further be substantially perpendicular to incoming flow from inlet 15, requiring all fluid flow to interact with example embodiment flow diverter system 200. The sequence of plates shown in the example of FIG. 4 significantly equalizes energetic fluid flows though all PCCS tubes 12 in a conventional PCCS system. Because chevron plate 201 and/or blocking plates 203 diverts flow away from inlet 15 lengthwise, energetic flow cannot overwhelm central PCCS tubes 12 directly below inlet 15. Further, because perforated plates 204 allow more flow at ends of upper manifold 11, PCCS tubes 12 at lengthwise ends of manifold 11 may receive larger amounts of flows, preventing backflows or circular flows though PCCS systems. Moreover, because plates in example embodiment system 200 are modular and may be relatively easily installed, removed, and/or swapped with other plates having desired flow characteristics such as chevrons, holes, or voids, levels and distributions of flows in upper manifold 11 can be fine-tuned and controlled to achieve desired flows simply by replacing or moving plates with particular characteristics to desired positions. Example embodiments and methods thus being described, it will be appreciated by one skilled in the art that example embodiments may be varied and substituted through routine experimentation while still falling within the scope of the following claims. For example, a variety of different fluid flow structures aside from PCCS manifolds are compatible with example embodiments and methods simply through proper dimensioning of example embodiments and fall within the scope of the claims. Such variations are not to be regarded as departure from the scope of these claims.
	abstract	The present invention relates to a control rod blade for a boiling water reactor. The control rod blade comprises a plurality of channels, which are arranged to receive an absorber material, a free edge portion with a recess, which comprises outlets for said channels, and a cover element , which is arranged to be attached by means of at least one welding operation such that it seals at least a part of said recess . Furthermore, the control rod blade comprises a profile element , which, before said welding operation of the cover element is performed, is arranged to be applied against a bottom surface in the recess in a position such that the profile element covers the outlets of said channels.
	summary
	summary
048048526	claims	1. In an ion implanter having an ion beam source and a scanning device disposed in a beam line between the source and an implant target, said scanning device serving to cause a spatial distribution across the target of the ions being implanted, said scanning device comprising a beam energy modulator means provided with a source of modulating voltage having a cyclical wave form to modulate the energy of the ions of the beam over time, and an analyzer magnet means disposed after said modulator means in position to act upon the thus modulated ion beam to cause displacement of the beam in a repetitively scanned pattern, the improvement wherein, under conditions of operation in which the intensity of said ion beam is unchanging, said wave form of said modulating voltage is preselected to take into account the non-linear relationship between the deflection of said beam by said magnetic means and the modulation of the energy of said beam, so as to produce a uniform areal distribution of the number of ions implanted into the target. 2. The ion implanter of claim 1 wherein said analyzer magnet means is constructed to produce a substantially constant and uniform magnetic field across the path of the ions through said magnet means, with flux lines extending substantially parallel to each other and perpendicular to the axis of the entering ion beam and said preselected wave form takes into account that the areal density of the ions of said beam in said scanned pattern is directly proportional to the amount of displacement of the beam from a reference position in said pattern. 3. The ion implanter of claim 1 wherein said analyzer magnet means is constructed so that the paths of the ions constituting the beam enter the entrance face of said magnet means at a fixed region and are bent by said magnet means through a predetermined arc selected so that ions of every energy emerge from said magnet means along substantially parallel paths. 4. The ion implanter of claim 1, 2 or 3 wherein the paths of ions of the beam are bent by said magnet means through an arc of about 180.degree. and the ions emerge from said magnet means along parallel paths which are substantially perpendicular to the exit face of said magnet means. 5. The ion implanter of claim 1, 2, or 3 wherein the paths of the ions constituting the beam are bent by said magnet means through an arc substantially less than 180.degree. and the ions emerge from said magnet means along paths which form an acute angle to the exit face of said magnet means. 6. The ion implanter of claim 5 wherein a projection of the plane of the exit face of the magnet means passes through the entry point of the centroid of said beam into said magnet means with the result that ion trajectories of different energy, which enter the magnet means at said point, emerge from said magnet means along essentially parallel paths. 7. The ion implanter of claim 1, 2 or 3 including means to move said target during the scanning of said beam, wherein said preselected wave form takes into account the dependence of the areal density of the ions being deposited on the implant target upon the position and motion of the target with respect to the beam position exiting from the magnet means. 8. The ion implanter of claim 1, 2 or 3 wherein a target carrier is arranged to carry said implant target through the beam, the path of said carrier describing a circular arc about an axis, said scanning device and carrier being cooperatively related to orient the scanning motion of said beam upon said carrier in the direction of the radius, R, of the arcuate motion of said carrier, and said wave form, in addition to taking into account the non-linear relationship between the deflection of the energy-modulated beam by said magnet means, simultaneously takes into account the 1/R dependence of the circumferential area of the target. 9. The ion implanter of claim 8 wherein the axis of said carrier is parallel to a line projected substantially through the point where the beam enters said analyzer magnet means and the source of modulating voltage has the wave form of a voltage ramp in which dV/dt=x(D-x) where V is voltage, t is time, x is the distance between the entrance and exit points of the beam relative to the magnet means and D is the distance from said carrier axis to the point of entry on said magnet means of the centroid of said beam so as to produce an implant into a workpiece of high spatial uniformity. 10. The ion implanter of claim 9 wherein said carrier carries the implant target under the scanned beam in the arc of a circle whose center line projects substantially through the point at which the modulated beam enters the analyzer magnet means so that the value of D is zero and the source of modulating voltage has the wave form of a voltage ramp in which dV/dt is constant, where V is voltage and t is time, so as to produce an implant into the workpiece of high spatial uniformity. 11. The ion implanter of claim 9 wherein said wave form increases in equal step-wise voltage increments in equal lengths of time. 12. The ion implanter of claim 8 wherein means are provided to invert the beam from said magnet means. 13. The ion implanter of claim 12 constructed according to claim 9, the axis of said carrier being parallel to a line projected substantially through the point where said beam enters said analyzer magnet means and is displaced therefrom said distance D on the opposite side of said beam. 14. The ion implanter of claim 8 wherein said carrier for moving said target comprises a rotating disc. 15. The ion implanter of claim 1, 2 or 3 wherein the implant target has neither a velocity nor an acceleration component in the direction of the scan of said beam and the said source of modulating voltage has the wave form of a voltage ramp in which increments of voltage, in equal increments of time, vary as the square root of the voltage. 16. The ion implanter of claim 15 wherein the implant target is stationary under said beam during the implantation. 17. The ion implanter of claim 16 wherein said source of modulating voltage has the wave form of a voltage ramp in which dV/dt=CV.sup.1/2 within the limits of V.sub.min and V.sub.max, where V is voltage, t is time and C is a constant, to produce a uniform areal distribution of the number of ions implanted into said stationary target. 18. The ion implanter of claim 1, 2 or 3 in which said wave form is selected to compensate for the position of said implant target with respect to said entrance point of said beam into said magnet means. 19. The ion implanter of claim 1, 2 or 3 in which said wave form is selected to compensate for the relative motion of said implant target with respect to the position of said beam on said target. 20. The ion implanter of claim 1, 2 or 3 in which said wave form is selected to compensate for the orientation of the plane of said implant target with respect to said beam position on said target. 21. The ion implanter of claim 1, 2 or 3 including two analyzer magnet means set orthogonally to one another, each associated with a respective energy modulating means which precedes it, the ion beam exiting the first of said magnet means entering the second of said magnet means, said two magnet means and associated energy modulation means producing a scan of said beam in two orthogonal coordinates. 22. The ion implanter of claim 1, 2 or 3 including means for exposing semiconductor wafer targets to said beam for the production of electronic circuits, said ion beam source being preselected to produce ions of a specie desired to be implanted in said semiconductor wafer targets. 23. In a method of implanting ions into an implant target comprising (a) producing an ion beam and (b) scanning the beam to provide a spatial distribution across the target of the ions being implanted, including: scanning the beam by modulating the beam with a source of modulating voltage having a cyclical wave form to modulate the energy of the ions of the beam over time, and passing the thus-modulated ion beam through an analyzing magnetic field selected to cause a scanning motion of the beam dependent upon said modulating voltage wave form, wherein the intensity of the ion beam is maintained substantially constant in time, said analyzing magnetic field is maintained substantially constant in time and uniform across the path of the ions through said field, with flux lines extending substantially parallel to each other and perpendicular to the axis of the entering ion beam, and the wave form for said modulating voltage is preselected to take into account the non-linear relationship between the deflection of said beam by said magnetic field and the modulation of the energy of said beam. a beam energy modulator means provided with a source of modulating voltage having a cyclical wave form to modulate the energy of the ions of the beam over time, and an analyzer magnet means disposed after said modulator means in position to act upon the thus modulated ion beam to cause displacement of the beam in a repetitively scanned pattern, a target carrier arranged to carry said implant target through the beam, the path of said carrier describing a circular arc, said scanning device and carrier being cooperatively related to orient the scanning motion of said beam upon said carrier in the direction of the radius of the arcuate motion of said carrier, said carrier arranged to carry the implant target under the scanned beam in the arc of a circle whose centerline projects substantially through the point at which the modulated beam enters the analyzer magnet means, said wave form of said modulating voltage being preselected to take into account the non-linear relationship between the deflection of said beam by said magnet means and the modulation of the energy of said beam and the dependence of the areal density of the ions being deposited on the implant target upon the position and motion of the target with respect to the beam position exiting from the said magnet means so as to produce an implant into a workpiece of high spatial uniformity. a beam energy modulator means provided with a source of modulating voltage having a cyclical wave form to modulate the energy of the ions of the beam over time, and an analyzer magnet means disposed after said modulator means in position to act upon the thus modulated ion beam to cause displacement of the beam in a repetitively scanned pattern a target carrier arranged to carry said implant target through the beam, the path of said carrier decribing a circular arc, said scanning device and carrier being cooperatively related to orient the scanning motion of said beam upon said carrier in the direction of the radius of the arcuate motion of said carrier, and means are provided to invert the beam from said magnet means and the axis of said carrier is parallel to a line projected substantially through the point where said beam enters said analyzer magnet means and is displaced therefrom an equal distance on the opposite side of said beam, said wave form of said modulating voltage being preselected to take into account the non-linear relationship between the deflection of said beam by said magnet means and the modulation of the energy of said beam and the dependence of the areal density of the ions being deposited on the implant target upon the position and motion of the target with respect to the beam position exiting from the said magnet means so as to produce an implant into a workpiece of high spatial uniformity. a beam energy modulator means provided with a source of modulating voltage having a cyclical wave form to modulate the energy of the ions of the beam over time, and an analyzer magnet means disposed after said modulator means in position to act upon the thus modulated ion beam to cause a displacement of the beam in a repetitively scanned pattern, said source of modulating voltage has the wave form of a voltage ramp in which dV/dt=CV.sup.1/2 within the limits of V.sub.min and V.sub.max, where V is voltage, t is time and C is a constant, there being two said analyzer magnet means set orthogonally to one another, each associated with a respective energy modulating means which precedes it, the ion beam exiting the first of said magnet means entering the second of said magnet means, said two magnet means and associated energy modulation means producing a scan of said beam in two orthogonal coordinates to produce a uniform areal distribution of the number of ions implanted into said stationary target. 24. The ion implantation method of claim 23 wherein the preselected wave form of said modulation of the beam energy takes into account conditions of operation to produce a uniform distribution of the number of ions implanted over the area of said target. 25. In an ion implanter having an ion beam source and a scanning device disposed in a beam line between the source and an implant target, said scanning device serving to cause a spatial distribution across the target of the ions being implanted, said scanning device comprising 26. The ion implanter of claim 25 wherein said carrier for moving said target comprises a rotating disc. 27. In an ion implanter having an ion beam source and a scanning device disposed in a beam line between the source and an implant target, said scanning device serving to cause a spatial distribution across the target of the ions being implanted, said scanning device comprising 28. The ion implanter of claim 27 wherein said carrier for moving said target comprises a rotating disc. 29. The ion implanter of any of the claims 25 through 28 wherein said source of modulating voltage has the wave form of a voltage ramp in which dV/dt is constant, where V is voltage and t is time. 30. The ion implanter of claim 29 wherein said wave form increases in equal step-wise increments in equal lengths of time. 31. In an ion implanter having an ion beam source and a scanning device disposed in a beam line between a stationary source and a stationary implant target, said scanning device serving to cause a spatial distribution across the target of the ions being implanted, said scanning device comprising 32. The ion implanter of claim 31 wherein, said analyzer magnet means is constructed so that the paths of the ions constituting the beam enter the entrance face of said magnet means at a fixed region and are bent by said magnet means through a predetermined arc selected so that ions of every energy emerge from said magnet means along substantially parallel paths. 33. The ion implanter of claim 32 wherein the paths of ions of the beam are bent by said magnet means through an arc of about 180.degree. and the ions emerge from said magnet means along parallel paths which are substantially perpendicular to the exit face of said magnet means. 34. The ion implanter of claim 32 wherein the paths of the ions constituting the beam are bent by said magnet means through an arc substantially less than 180.degree. and the ions emerge from said magnet means along paths which form an acute angle to the exit face of said magnet means and wherein a projection of the plane of the exit face of the magnet means passes through the entry point of the centroid of said beam into said magnet means with the result that ion trajectories of different energy, which enter the magnet means at said point, emerge from said magnet means along essentially parallel paths. 35. The ion implanter of claim 32, 33 or 34 wherein said analyzer magnet means is constructed to produce a substantially constant and uniform magnetic field across the path of the ions through said magnet means, with flux lines extending substantially parallel to each other and perpendicular to the axis of the entering ion beam and said wave form is selected to take into account that the areal density of the ions in the scanned beam is directly proportional to the amount of said displacement.
044774109	description	DETAILED DESCRIPTION FIG. 1 shows the protective wall 1 of a fast fission nuclear reactor, to which the slab 2 covering the reactor vessel is fixed. The main vessel 3 is fixed to the slab in its upper part, while the safety vessel 4, covered with a layer of insulating material 5, is fixed to the protective wall 1. Up to the level 6, the main vessel 3 contains liquid sodium, in which the reactor core 7 is immersed, which rests on a bed 8 and a floor 9, itself resting on the bottom of the main vessel 3. The interior volume of the main vessel 3 is separated into two different zones by a double partition 10, which is supported by the floor 9 at the periphery of the core and consists of an annular wall 11 and a cylindro-conical wall 12. This double partition, also referred to as a step, makes it possible to isolate the sodium contained in the upper zone 14, containing the core 7, from the sodium contained in the annular lower zone 15. Intermediate heat exchangers and pumps, not shown, make it possible firstly to cool the hot sodium contained in the zone 14 in contact with the secondary sodium, to transfer this sodium from the zone 14 to the zone 15, and finally to inject the cold sodium removed from the zone 15, into the lower part of the core, in the bed 8. The cold sodium re-injected into the base of the core passes through the latter from bottom to top, heats up and then passes from the zone 14 to the zone 15 via the intermediate exchangers. In addition to the step, an external shell 16 and an internal shell 17 are arranged in the vessel and coaxially thereto, and those parts of these shells which are located above the zone 15 delimit between one another, and between the outer shell and the main vessel 3, two annular spaces 19 and 20, in which the cold sodium circulates. To permit this circulation of cold sodium, the shell 16 is extended so as to bring the space 19 into communication with the base of the core, under the bed 8, at the point where the cold sodium is injected. As shown by the arrows 21, a circulation of cold sodium is set up from bottom to top in the annular space 19 created between the external shell 16 and the main vessel 3. In the top part of the annular passage 19, which emerges, under the slab 2, in the space 24 created between the slab and the liquid sodium level 6 and filled with an inert gas, for example argon, the cold liquid sodium flows along the shell 16, inside the annular space 20, this sodium moving down again, by gravity, into the part 15 of the vessel, containing the cold sodium. The annular passage 20 is brought into communication with the zone 15 containing the cold sodium, via a calibrated orifice 25, making it possible to adjust the pressure drop during the circulation of the sodium. The circulation of the cold sodium in contact with the internal wall of the main vessel 3 makes it possible to cool the latter and to keep it at a temperature which is virtually constant and corresponds to the temperature of the sodium before it enters the core. The pumping of the liquid sodium and the pressure drop during its circulation make it possible to maintain a difference in level between the sodium filling the tube 19 and the sodium flowing into the tube 20. FIG. 2 shows the elements corresponding to those shown in FIG. 1, provided with the same reference numbers. In contrast to the embodiment of the cooling device shown in FIG. 1 and corresponding to the prior art, the annular space 19 is brought into communication by a series of calibrated openings 30, making it possible to ensure an adjusted pressure drop during the circulation of the sodium, with the annular zone 15 containing the cold sodium, whereas the annular space 20 is brought into communication, via tubes 31, with the zone of the vessel located underneath the bed 8, into which the cold sodium is injected. In this way, the cold sodium circulates in the direction indicated by the arrows 32. The cold sodium therefore circulates first inside the tubes 31, through which it reaches the annular space 20, through which it passes from bottom to top up to the level of the space between the slab and the liquid sodium level 6, where the upper end of the outer shell 16 is located. The cold sodium then flows, by gravity, into the annular space 19, along the external surface of the shell 16. A difference in sodium level in the annular spaces 20 and 19, respectively, is maintained, as previously, by virtue of pumping and by the pressure drop, in particular at the level of the openings 30. In the external annular space 19, the sodium flows downwards, by gravity, in contact with the internal surface of the main vessel 3, which it cools and keeps at the temperature of the cold sodium, i.e., at about 400.degree. C. The cold sodium returns to the zone 15 via the calibrated openings 30. It is seen that, compared with the device according to the prior art, shown in FIG. 1, the device according to the invention has the advantage of placing the external shell 16 under internal pressure, whereas this shell is under external pressure in the device of the prior art. Likewise, the lower part of the baffle, which extends the shell 16 down to the level of the bed 8, is now subjected only to an internal differential pressure of low amplitude. In this way, it is possible to reduce the thickness of the shell 16 and thus to make a substantial weight saving in the design of the reactor. The difference in level h between the sodium filling the annular space and the sodium flowing in the annular space 19 is of the order of two meters for the nuclear reactors currently being constructed, the vessel of which has a diameter of the order of twenty meters. The part of the main vessel 3 which is located over this height h, between the sodium level in the space 20 and the sodium level in the space 19, is not in contact with the sodium as in the case of the device of the prior art. However, this does not give rise to large temperature differences between the points of the vessel which are in contact with this sodium and the points of the vessel which are in contact with the gas on top of the sodium, because, in the first place, the safety vessel 4 is lagged, which prevents heat looses from the main vessel, and, in the second place, the heat supplied by the radiation from the external shell 16, at the level of the zone of height h, keeps the main vessel, in this zone, at a temperature close to the temperature of the remainder of the vessel. FIG. 3 shows a second embodiment of the cooling device according to the invention, in which the shell 17 is of reduced height and in which the space 20 is in communication, by its lower part, with the lower part of the core, via tubes, such as 35, passing through the central space in the partition 10, located between the two parts of the partition constituting the step. As in the case of the device shown in FIG. 2, the annular space 19 communicates with the zone 15 containing the cold sodium, by means of calibrated orifices such as 30. The operation of the device is virtually identical to the operation of the device shown in FIG. 2, a small part of the cold sodium injected under the bed 8 passing into the tube 35, and from there into the annular space 20 constituting a channel for the sodium flowing in the annular space 19, for the cooling of the main vessel 3 and and return of the sodium into the annular zone via the openings 30. This device has the same advantages as the device shown in FIG. 2. The invention is not limited to the embodiments which have been described; on the contrary, it includes all the variants thereof. Thus, it is possible to envisage other means for connecting the annular space 20, constituting a channel for the liquid sodium, to the lower part of the core. It is also possible to envisage any kind of connection between the space 19, created between the main vessel and the external shell, and the zone, such as 15, containing the cold sodium, for the recycling of the latter. The device according to the invention can apply irrespective of the shape and structure of the step, whether the latter consists of a single partition or a double partition. Finally, the device according to the invention applies in the case of all integrated-type fast fission reactors.
	description	The invention relates generally to optics, and more particularly to multilayer optic devices and methods for making the same. Numerous applications exist that require a focused beam of electromagnetic radiation. For example, energy dispersive X-ray diffraction (EDXRD) may be used to inspect checked airline baggage for the detection of explosive threats or other contraband. Such EDXRD systems may suffer from high false positives due to weak diffracted X-ray signals. The weakness of the X-ray signals may stem from a variety of origins. First, the polychromatic X-ray spectrum used in EDXRD is produced by the Bremsstrahlung part of the source spectrum, which is inherently low in intensity. Second, X-ray source collimation may eliminate more than 99.99 percent of the source X-rays incident on the baggage volume under analysis. Third, some of the materials being searched for, e.g., explosives, may not diffract strongly as they are amorphous. Fourth, the diffracting volume may be small. The last two limitations arise from the type of threat materials being searched for in baggage, making all but the second limitation unavoidable. Although discussed in the context of explosives detection, the limitations described above are equally applicable to medical situations. At lower X-ray energies, such as 80 keV and below, increasing the polychromatic X-ray flux density at the material being inspected has been addressed by coupling hollow glass polycapillary optics to low powered, sealed tube (stationary anode) X-ray sources. An example of hollow glass polycapillary optics may be found in, for example, U.S. Pat. No. 5,192,869. The glass is the low index of refraction material, and air filling the hollow portions is the high index of refraction material. These types of optics typically do not provide much gain at energy levels above 80 keV, since the difference in the indices of refraction between air and glass becomes increasingly small as energy levels approach and surpass 80 keV. Further, such optics use a concept of total internal reflection to reflect X-rays entering the hollow glass capillaries at appropriate angles back into the hollow capillaries, thereby channeling a solid angle of the source X-rays into collimated or focused beams at the output of the optic. As used herein, the term “collimate” refers to altering the divergence of beams of electromagnetic (EM) radiation from the intrinsically divergent EM beams. Only about five percent of an EM source's solid angle typically is captured by the input of such known optics. In addition, the use of air in known optics as one of the materials prevents such optics from being placed within a vacuum. Thus, known optics are limited in their potential uses. The shaping of an X-ray spectrum to optimize it for particular applications is a common procedure. The change in the spectral shape, for example, reducing either the relative proportion of low-energy X-rays or the relative proportion of high-energy X-rays, can in some cases provide for optimum imaging of a sample. One common artifact in radiographic and tomographic imaging arises from the fact that the lower energy X-rays in a typical Bremsstrahlung (polychromatic) spectrum are attenuated preferentially as the beam penetrates material. This effect, which leads to an increase in the mean energy of the beam as it penetrates the sample, introduces a biasing in the relationship between the strength of the transmitted beam and the amount of material penetrated. This biasing manifests as artifacts in any images reconstructed from the attenuation data, such as those attributed to beam hardening in computed tomography. Utilizing an X-ray beam that has a reduced spread of energies can mitigate some of these artifacts. Particularly where beam intensity, with respect to the intensity in that same range of the original spectrum, has been held constant or augmented by the use of the optic, the use of a limited range of energies can provide a desired degree of attenuation for a particular application and can produce an optimum image in terms of spatial resolution and contrast sensitivity. The shaping of a spectrum from a polychromatic energy distribution to a more monochromatic distribution can enable such improvements in X-ray image sets. Spectral imaging also includes a single energy distribution as well as multi-energy distributions. Multi-energy X-ray imaging, sometimes referred to as dual-energy imaging or energy discrimination imaging, has been shown to furnish information on specific material compositions in scanned objects for security, industrial, and medical applications. Such energy discrimination imaging can be achieved in several ways, including the use of two or more different X-ray spectra, which is often the most feasible approach. A challenge lies in the sequential nature of such an examination, where image data are generated, for example, first with one spectrum and then with another spectrum. In one technique, an object of interest is scanned twice. A first complete projection data set is produced in the first scan for one energy and then a second complete projection data set is produced in the second scan for the second energy. For many applications where high throughput is critical, sample composition is dynamic, and/or sample positioning may preclude repetitive scanning, the logistics of physically scanning an object twice may be unacceptable. Conventional multi-energy X-ray imaging applications have used source filtration and/or high voltage modulation for rapidly altering the spectral characteristics on a time scale comparable to the view-by-view sampling time in a typical CT scan. Such filtration consists of rapidly and sequentially inserting filters of appropriate composition to preferentially attenuate relatively low X-ray energies. Such methodologies are limited in the degree to which attenuation can produce cleanly separated energy intervals, severely restricting the sensitivity of this approach for analyzing different materials. High voltage modulation to produce different spectral characteristics also has been implemented in some cases with limited success. There is a challenge in both approaches to mitigate registration differences in the image reconstruction projections that result from sample movement between data sets acquired at different energies, as well as a slight misalignment of the X-ray paths that traverse the object, as is incurred with modulating the X-ray beam on a sub-view basis. The invention includes embodiments that relate to an optic assembly that includes an optic device and a filtering mechanism. The optic device transmits a desired range of X-ray energies through at least one of total internal reflection, diffraction, and refraction. The optic device includes at least three conformal solid phase layers, wherein interfaces between the solid phase layers are gapless and wherein the at least three conformal solid phase layers include at least one X-ray redirection region. The filtering mechanism filters out certain energies from a beam transmitted by the optic device. The filtering mechanism is at least one of a filtering apparatus external to the optic device and a filtering apparatus integral to the optic device. The invention includes embodiments that relate to an array of optic devices that includes a first optic portion for transmitting high X-ray energies or high and low X-ray energies and a second optic portion for transmitting low X-ray energies. The invention includes embodiments that relate to a method for forming a high-energy spectrum image by subtracting a low-energy spectrum from a high-and a low-energy spectrum image. The method includes transmitting high and low X-ray energies through an optic device using at least one of total internal reflection, diffraction, and refraction. The method also includes filtering out certain energies from a beam transmitted by the optic device to generate the high-energy spectrum image utilizing a filtering mechanism, wherein the filtering mechanism is at least one of a filtering apparatus external to the optic device and a filtering apparatus integral to the optic device. The invention includes embodiments that relate to a multi-energy imaging system that includes a source of electrons, a target for forming X-rays upon being struck by electrons from the source of electrons, a vacuum chamber housing the target, and a window through which the X-rays may exit the vacuum chamber. The system also includes at least one optic device configured to transmit a desired range of X-ray energies. The invention includes embodiments that relate to a method for manufacturing a multi-energy imaging system for filtering low-energy X-rays from high-energy X-rays in an imaging system. The method includes providing a target configured to form X-rays upon being struck with electron beams and providing at least one optic device in optical communication with the target. The at least one optic device is formed to transmit high X-ray energies or to transmit low X-ray energies. These and other advantages and features will be more readily understood from the following detailed description of preferred embodiments of the invention that is provided in connection with the accompanying drawings. Embodiments of the invention described herein primarily utilize the phenomenon of total internal reflection. Referring to FIG. 1, when an angle of incidence is less than a critical angle θc, total internal reflection occurs. The critical angle θc for total internal reflection depends on, among other factors, the selection of materials, the difference in the relative indices of refraction between the materials, the material photon absorption properties, and the energy of the incident photons. By appropriate material selection in the multilayer optic described herein, the critical angle θc can be increased several times over an air-glass critical angle, allowing many more photons to satisfy the condition for total internal reflection. This will allow a greater photon transmission through a multilayer optic than is possible with, for example, polycapillary optics. Referring now to FIGS. 2-5, there is shown a multilayer optic 10 including an input face 12 and an output face 14. By “multilayer” is meant a structure that has a plurality of layers with each layer having a single composition. As shown more particularly in FIGS. 3 and 4, the multilayer optic 10 includes multiple layers of material, each having a different index of refraction. For example, there are layers 16, 20, and 24 surrounding a core 50. Layer 15, formed of a lower index of refraction material, is positioned radially exterior to and contiguous with the core 50. The core 50 may be formed of a higher index of refraction material such as beryllium, lithium hydride, magnesium, or any other suitable elements or compounds having similarly higher refractive indices and high X-ray transmission properties. The core 50 may be less than a micrometer to greater than one centimeter in diameter. Layer 20 is positioned radially exterior to layer 16 and radially interior to layer 24. In one embodiment, the layers making up the multilayer optic 10 may be formed of materials that have varying indices of refraction. For example, layers 15, 19, 23, and 27 may be formed of materials that have a lower index of refraction and a high X-ray absorption. For example, appropriate materials may be chosen from osmium, platinum, gold, or any other suitable elements or compounds having similarly lower refractive indices and high X-ray absorption properties. Further, the core 50 and layers 16, 20, and 24 may be formed of materials having a higher index of refraction and a high X-ray transmission. For example, appropriate materials may be chosen from beryllium, lithium hydride, magnesium, or any other suitable elements or compounds having similarly higher refractive indices and high X-ray transmission properties. The diameter of the core 50 is computed by considering the location of the X-ray radiation source focal point relative to the input face of the optic and the required critical angle for total internal reflection between the higher index of refraction of the core 50 and the lower index of refraction of the layer 15. By using alternating lower and higher index of refraction materials with concurrent high and low X-ray absorption properties, respectively, in contiguous layers, the multilayer optic 10 can utilize the principle of total internal reflection of electromagnetic radiation. Specifically, diverging electromagnetic radiation beams 38, 40, and 42 stemming from an electromagnetic radiation source 34 enter the input face 12 and are redirected by the principle of total internal reflection into quasi-parallel beams of photons 44 exiting the output face 14. Multilayer optics in accordance with embodiments of the invention, such as optic 10, can collect a large solid angle of an X-ray source 34 and redirect photons containing polychromatic energies into quasi-parallel photon beams. “Quasi-parallel” means that diverging beams of photons, such as X-rays, have been collected and focused into beams of electromagnetic radiation or X rays to exit the output face 14 at or below the critical angle θc. This divergence causes the intrinsic source X-ray beam to be larger than the output face 14 of the optic 10 and larger than the parallel beam of X rays produced by the optic. Alternatively, multilayer optics in accordance with embodiments of the invention may be configured to produce slightly focused, highly focused, slightly diverging, or highly diverging beams. By “slightly focused” is meant that the beam size at the point of interest (i.e., where the diameter of the beam is of concern) is approximately the same as the beam at the output face 14 of the optic 10. By “highly focused” is meant that the beam size at the point of interest is smaller than the beam at the output face 14 of the optic 10. By “slightly diverging” is meant that the beam size is larger than a quasi-parallel beam but smaller than the intrinsic source beam. By “highly diverging” is meant that the beam is the same size or larger than the intrinsic source beam. The phrase “intrinsic source beam” is meant to represent an X-ray beam emitted from the source housing with no optic in the beam. The composition of materials making up the multilayer optic 10, the macroscopic geometry of the multilayer optic 10, the thickness of the multilayer optic 10, and the number of individual layers determine the angular acceptance range of the multilayer optic 10. The angular acceptance range may be from about 0 steradians up to about 2π steradians of a solid angle of a photon source. For ease of illustration, only a few layers have been illustrated with reference to multilayer optic 10. However, it should be appreciated that any number of layers, including into the hundreds, thousands, or millions of layers, can be fabricated to utilize total internal reflection to form the various types of photon beams listed previously. Another feature of the multilayer optic 10 is that the core 50 and the layers 16, 20, 24 may have photon, or X-ray, redirection regions. For example, layer 16 has a photon redirection region 17 stemming from a center of curvature; layer 20 has a photon redirection region 21 stemming from a second center of curvature; and, layer 24 has a photon redirection region 25 stemming from yet another center of curvature. The photon redirection regions 17, 21, 25 are chosen to allow for the diverging electromagnetic radiation beams 38, 40, and 42 to be made parallel or near parallel to beam 36, or conversely to allow for parallel or converging electromagnetic radiation beams to be made diverging. The minimum photon redirection region is determined by the minimum thickness that would still enable a smooth surface, which is at least two atomic layers, or about ten angstroms. The photon redirection regions 17, 21, 25 each contain redirecting segments. The redirecting segments are chosen such that they each have a constant curvature. The curvature of each redirecting segment may be the same as or different from the curvatures of other redirecting segments. If each of the redirecting segments for a particular photon redirection region is straight, then the radius of curvature is infinite. By curving the multilayers 16, 20, 24 at the input side of the optic 10, the photons or electromagnetic radiation 38, 40, 42 entering the input face 12 can be redirected into quasi-parallel pencil beams 44, thereby increasing the photon flux density at the output face 14 over the photon flux density in the direct source beam (X-ray beam without the optic) at the same distance from the source 34. Depending upon the number of layers in the multilayer optic, there may be a photon density gain for 100 keV photons of as much as 5000 times in the output intensity of electromagnetic radiation from the multilayer optic over the output of conventional pinhole collimators. It should be appreciated that, alternatively, the output face 14 may be formed closer to the input face 12, i.e., positioned prior to the region where the photons are redirected into parallel rays, allowing the input electromagnetic radiation beams 38, 40, 42 to remain somewhat diverging as they exit the output face 14. It should further be appreciated that core 50 and any number of the layers may have no arc of curvature, instead having a cylindrical cross-sectional profile. An important feature of this optic 10 is that the X-ray transmitting layers, for example, layers 16, 20, 24, can be made thin enough—on the order of a few nanometers—that the solid angle of source photons collected by these layers are small enough to accept almost all the X-rays entering the layers, i.e. the X-ray trajectories satisfy the critical angle condition for total internal reflection. This is unlike known optics, where the X-ray transmitting regions are on the order of microns thick and a significant number are absorbed at the reflecting interface because the photon trajectories do not satisfy the critical angle condition for total internal reflection. In addition, the X-ray absorption layers are orders of magnitude thinner than in known optics making the X-ray transmission of known optics orders of magnitude smaller than the optics described in this application. Furthermore, the overall optic length (from input face 12 to output face 14) is short enough that photon losses are minimal. Another feature of the multilayer optic 10 is that through fabrication techniques that will be described in detail below, the individual layers can be formed conformally on one another. The conformation of the layers enables the multilayer optic 10 to be utilized in a vacuum environment. Prior art optics utilize air as the higher refractive index material. Such optics cannot be used in vacuum environments. Further, the multilayer optic 10 can be utilized in applications that operate at energy levels above 60 keV, such as, for example, X-ray diffraction, medical and industrial CT imaging, medical and industrial X-ray, and cargo inspection, to name a few. Some of these applications may operate at energy levels as high as 450 keV. Referring now to FIG. 6, there is shown a multilayer optic 110 including a plurality of layers 113a-113n, one on top of the other, extending between an input face 112 and an output face 114 having a polygonal profile. As illustrated, the middle layer of the multilayer optic 110 is layer 113mid. Except for layer 113mid, all of the layers include a photon redirection region positioned between the input face 112 and the output face 114. It should be appreciated, however, that layer 113 mid may include a photon redirection region, or that other layers in addition to 113 mid may lack a photon redirection region. The design shown allows diverging electromagnetic radiation to be input into the input face 112, redirected by the optic multilayers, and output from the output face 114 into a reduced cone beam, such as, for example, a reduced cone fan beam. Depending upon where the output face 114 is located relative to the photon redirection regions, the fan beams may be parallel or near parallel or may be somewhat divergent but still focused relative to the input electromagnetic radiation. Additionally, the conformal nature of the individual layers allows for the multilayer optic 110 to be utilized in a vacuum environment. Referring to FIG. 7, there is shown a multilayer optic 210 that includes an input face 212 and an output face 214. As with the embodiment shown in FIG. 6, the multilayer optic 210 includes individual layers sandwiching a mid-layer. The design shown allows for a focused fan beam output. As with the previously described embodiments, the conformal nature of the individual layers allows the multilayer optic 210 to be used in a vacuum environment. FIG. 8 illustrates a multilayer optic 310 having an input face 312 and an output face 314. The layers have been positioned over a cone 150, which serves as a blank or mold for the individual layers. Through this design, the output beam exiting the output face 314 is shaped into a curved output, which can be coupled to a singly curved diffracting crystal (not shown) to enable the creation of a cone beam of highly monochromatic radiation. Monochromatic radiation is used in several different applications, including, for example, X-ray diffraction. Highly monochromatic radiation is radiation within a very narrow energy range approximately equal to that produced by diffracting from a single crystal. The curved diffracting crystal can be formed of any suitable material, such as, for example, mica, silicon, germanium, or platinum and curved so that the crystal conforms to the surface of, for example, a cone or cylinder. The suitability of any material for use as the diffracting crystal is dependent upon the diffraction intensity and the lattice spacing of the material. It should be appreciated that the multilayer optic 310 should be positioned between the source of the electromagnetic radiation and the diffracting crystal to obtain the maximum photon flux density in the diffracted beam. Placing a filter at the input or the output faces of the optics in FIGS. 5-7 will make the optics' output radiation quasi-monochromatic. Quasi-monochromatic radiation is radiation within a limited wavelength range that is greater than the highly monochromatic range but less than the full Bremsstrahlung spectrum from an X-ray source. FIGS. 9-12 illustrate various other potential embodiments of multilayer optics. FIGS. 9 and 10 illustrate multilayer optics that have output faces in a photon redirection region, thereby allowing such optics to emit highly diverging beams. FIGS. 11 and 12 illustrate multilayer optics whose output faces are dimensionally smaller than their respective input faces, allowing such optics to emit highly focused beams. Referring now to FIG. 13, next will be described an apparatus for use in forming a multilayer optic. Specifically, a multilayer optic deposition assembly 400 is shown including a deposition chamber 402 and a movable shutter apparatus 410. The deposition chamber 402 may be utilized in suitable deposition techniques, including, for example, vapor deposition, or thermal spray deposition. Suitable vapor deposition techniques include sputtering, ion implantation, ion plating, laser deposition, evaporation, and jet vapor deposition. Evaporation techniques may include thermal, electron-beam, or any other suitable technique resulting in appreciable deposition of material. Suitable thermal spray deposition includes combustion, electric arc, and plasma spray. The deposition chamber 402 includes an inputting apparatus 404 for allowing ingress of deposition materials into the deposition chamber 402. It should be appreciated that the inputting apparatus 404 may include numerous inlet nozzles, each being associated with a specific deposition material. A blank 420 is positioned within the deposition chamber 402. The blank 420 may be a core 50 or a cone 150, described previously with regard to the embodiments illustrated in FIGS. 4 and 8, or it may be a substrate serving as a support mechanism for deposited layers. It should be appreciated that the blank 420 can assume virtually any suitable geometric configuration consistent with the desired beam profile. Examples of the almost infinite number of suitable geometric configurations include a circular wafer, a rectangular prism, a cone, a cylinder, and an egg-shape, to name a few. The shutter apparatus 410 enables the formation of a multilayer optic wherein the individual layers have a photon redirection region. Specifically, as a deposition material is input into the deposition chamber 402 through the inputting apparatus 404, the shutter apparatus 410 moves in a direction A relative to the blank 420. If the speed of the shutter apparatus 410 decreases as it moves in the direction A, an increasing amount of deposition material will contact the blank 420 in the direction A, thereby enabling the formation of a multilayer optic with individual layers having different thicknesses and having photon redirection regions. Control of the movement and velocity of the shutter apparatus 410 may be accomplished electronically with a digital controlling mechanism, such as a microcontroller, microprocessor, or computer. Alternatively, control of the movement may be accomplished manually, or mechanically, such as, pneumatically, hydraulically, or otherwise. By moving the shutter apparatus 410 along direction A as each deposition material is input through the inputting apparatus 404 into the deposition chamber 402, the individual layers can be deposited upon the blank 420, and a multilayer optic having conformal individual layers, like the multilayer optic 110 shown in FIG. 6, can be formed. In forming a multilayer optic like the multilayer optic 110, the first layer to be laid down may be the layer adjacent to mid-layer 113mid. Then, the subsequent layers leading to and including layer 113a can be deposited. Then, the partially formed multilayer optic can be turned over and the layers leading to and including layer 113n can be deposited. Further, assuming a constant rate of deposition material being injected into the deposition chamber 402, if the shutter apparatus 410 is programmed to begin with a first velocity, transition into a second different velocity, and then transition back to the first velocity, a multilayer optic like the multilayer optic 210 shown in FIG. 7 can be formed. It should be appreciated that the deposition rate of the deposition material in the deposition chamber 402 may be altered as well. Instead of utilizing a shuttle apparatus 410, it is possible to move at varying speeds the inputting apparatus 404 relative to the blank 420. Further, it is possible to move at varying speeds the blank 420 within the deposition chamber 402 relative to the inputting apparatus 404. Referring to FIG. 14, there is shown a multilayer optic deposition assembly 500 that includes a deposition chamber 502 and the movable shutter apparatus 410. The deposition chamber 502 includes the inputting apparatus 404 that is the source of a vapor stream and a pair of rotatable spindles 505. The spindles 505 are capable of rotating in a direction B. Further, the spindles 505 each include a pointed end that comes into contact with and holds the blank 420. By rotating the spindles 505 in the same direction B the blank 420 can be rotated while deposition material is introduced into the deposition chamber 502 though the inputting apparatus 404. Movement of the shutter apparatus 410 in the direction A and rotation of the blank 420 in the direction B will enable the formation of a multilayer optic such as the multilayer optic 10 shown in FIG. 5. Alternatively, the spindles 505 can remain in a non-rotating state during a first set of deposition steps to form the layers adjacent to layers 113mid to 113a in FIG. 6. Then, the spindles 505 can be rotated to turn the partially formed multilayer optic one hundred and eighty degrees around to allow for a second set of deposition steps to form the layers leading to and including 113n to form the multilayer optic 110. Instead of utilizing a shutter apparatus 410, it is possible to move the inputting apparatus 404 at varying speeds relative to the blank 420 while the blank 420 is being rotated by the spindles 505. Further, it is possible to move the spindles 505 and the blank 420 within the deposition chamber 402 at varying speeds relative to the inputting apparatus 404. Alternatively, while spinning the blank 420, the inputting apparatus 404 may be kept stationary, with its vapor beams focused to different heights along the blank 420. The resulting different deposition rates will create the depth and laterally graded inputs and outputs on the optic and will enable the formation of a multilayer optic such as the multilayer optic 10 shown in FIG. 5. FIG. 15 illustrates process steps for forming a multilayer optic in accordance with an embodiment of the invention. At Step 600, a material having a pre-determined index of refraction with a pre-determined photon transmission coefficient is deposited. The material is deposited on a blank or substrate, which may be a core, a cone, or a polygonal support mechanism. It should be appreciated that the blank or substrate may be incorporated within the multilayer optic, such as the core 50, or may serve merely as a mold, like cone 150. Then, at Step 605, another material having a prescribed index of refraction with a photon transmission coefficient is deposited onto the previous material in such a way as to be conformal and have minimal void spaces. It should be appreciated that each individual layer may be formed at thicknesses in the range of one nanometer to thousands of nanometers. After Step 605, the Steps 600 and 605 can be sequentially repeated to prepare, for example, multiple pairs of layers, with each pair having one layer having a first index of refraction with a first photon transmission coefficient and a second layer having a second index of refraction with a second photon transmission coefficient. The deposition of the first and second materials may be accomplished by any number of suitable processes, such as, for example, vapor deposition, thermal spray deposition, or electroplating. As noted previously, examples of suitable vapor deposition techniques include sputtering, ion implantation, ion plating, laser deposition (using a laser beam to vaporize a material or materials to be deposited), evaporation, or jet vapor deposition (using sound waves to vaporize a material or materials to be deposited). Also, as noted previously, evaporation techniques may be thermal, electron-beam or any other suitable technique that will result in appreciable deposition of material. Examples of suitable thermal spray deposition techniques include combustion, electric arc, and plasma spray. It should be appreciated that during the deposition process, the partially formed multilayer optic may be rotated, oscillated, or moved. It may be turned, and it may be subjected to a deposition process whereby the deposition material is deposited at different rates along the axis of the multilayer optic. In this way, multilayer optics can be formed with various configurations and profiles that will allow for a greater amount of electromagnetic radiation to be collected from a source at the input of the optic, parallel or near parallel beams of electromagnetic radiation to be output from the multilayer optic, or beams of electromagnetic radiation output from the multilayer optic to be shaped into pencil beams, cone beams, fan beams, or curved in an arc, as an example. Multilayer optics in accordance with embodiments of the invention may be used in various industrial applications. For example, a multilayer optic formed to emit a quasi-parallel beam having a circular cross-section may find utility in X-ray diffraction and backscatter applications, such as non-destructive examination. A multilayer optic formed to emit a slightly focused beam with a circular cross-section may find utility in X-ray diffraction, X-ray fluorescence, medical diagnostic or interventional treatments, and non-destructive examination applications. Multilayer optics formed to emit a highly focused beam having a circular cross-section may find utility in X-ray fluorescence; medical diagnostic or interventional treatments of, for example, small tumors; and, non-destructive examination applications. Multilayer optics formed to emit a slightly diverging beam having a circular cross-section may find utility in computed tomography and X-ray diagnostic system applications. Multilayer optics formed to emit a highly diverging beam having a circular cross-section may find utility in non-destructive examination applications requiring an increased field-of-view, and in medical diagnostic or interventional imaging and treatments requiring an increased field-of-view, such as the imaging and treatment of large tumors. One example of the utility of multilayer optics formed to emit a variety of beam shapes is in medical interventional treatments, such as treatment of tumors, where the optic shape is determined by the tumor shape. Such multilayer optics would allow X rays to be focused onto the tumor without irradiating nearby healthy tissue, providing targeted treatment with a minimum of damage to surrounding healthy tissue. Multilayer optics formed to emit a fan beam in one plane that is quasi-parallel, slightly focusing, highly focusing, slightly diverging, or highly diverging in a direction transverse to the plane may find utility in computed tomography, X-ray diagnostic system, and non-destructive examination applications. The fan beam may have a divergence the same as or greater than that of the source. Alternatively, multilayer optics formed to emit a quasi-parallel fan beam in one plane that is quasi-parallel, slightly focused, highly focused, slightly diverging, or highly diverging within the plane of the fan would produce a beam having a rectangular cross-section that may find utility in computed tomography, as well as non-destructive and medical examination applications. Multilayer optics formed to emit a fan beam in one plane that is slightly or highly diverging in the direction transverse to the fan beam plane may find utility in medical interventional applications, such as close-up imaging to increase field-of-view. The divergence in the direction transverse to the fan beam plane is equal to or greater than the source divergence. Multilayer optics formed to emit a fan beam in one plane that is quasi-parallel, slightly focusing, highly focusing, slightly diverging, or highly diverging perpendicular to the plane of the fan may find utility in computed tomography, X-ray diagnostic system, and non-destructive examination applications. The fan beam may have a divergence the same as or greater than that of the source. A multilayer optic coupled to a diffracting crystal may produce a quasi-parallel monochromatic fan beam that may find utility, provided the intensity is great enough, in medical imaging and interventional treatments. Such monochromatic imaging would reduce a patient's dose of X-rays while increasing the resolution, for example, by reducing cone beam artifacts, and reducing streaking/shading such as those incurred with beam hardening effects. FIG. 16 illustrates a conventional acquisition system 700 for use in an object detection system, such as, for example, a computed tomography (CT) scanner. The acquisition system 700 comprises a scanner 702 formed of a support structure and internally containing one or more stationary or rotationally distributed sources of X-ray radiation (not shown in FIG. 16) and one or more stationary or rotational digital detectors (not shown in FIG. 16), as described in greater detail below. The scanner 702 is configured to receive a table 704 or other support for an object to be scanned, such as, for example, baggage or luggage or patients. The table 704 can be moved through an aperture in the scanner to appropriately position the subject in an imaging volume or plane that is scanned during imaging sequences. The system further includes a radiation source controller 706, a table controller 708 and a data acquisition controller 710, which may all function under the direction of a system controller 712. The radiation source controller 706 regulates timing for discharges of X-ray radiation which is directed from points around the scanner 702 toward a detector element on an opposite side thereof, as discussed below. The radiation source controller 706 may trigger one or more emitters in a distributed X-ray source at each instant in time for creating multiple projections or frames of measured data. In certain arrangements, for example, the X-ray radiation source controller 706 may trigger emission of radiation in sequences to collect adjacent or non-adjacent frames of measured data around the scanner. Many such frames may be collected in an examination sequence, and data acquisition controller 710, coupled to detector elements as described below, receives signals from the detector elements and processes the signals for storage and later image reconstruction. In configurations described below in which one or more sources are rotational, source controller 706 may also direct rotation of a gantry on which the distributed source or sources are mounted. Operation of the gantry also may be controlled by the system controller 712 or a separate controller altogether. Table controller 708, then, serves to appropriately position the table and subject in a plane in which the radiation is emitted, or, in the present context, or generally within a volume to be imaged. The table may be displaced between imaging sequences or during certain imaging sequences, depending upon the imaging protocol employed. Moreover, in configurations described below in which one or more detectors or detector segments are rotational, data acquisition controller 710 may also direct rotation of a gantry on which the detector or detectors are mounted. System controller 712 generally regulates the operation of the radiation source controller 706, the table controller 708 and the data acquisition controller 710. The system controller 712 may thus cause radiation source controller 706 to trigger emission of X-ray radiation, as well as to coordinate such emissions during imaging sequences defined by the system controller. The system controller may also regulate movement of the table in coordination with such emission to collect measurement data corresponding to volumes of particular interest, or in various modes of imaging, such as helical modes. Moreover, system controller 712 coordinates rotation of a gantry on which the source(s), detector(s), or both are mounted. The system controller 712 also receives data acquired by data acquisition controller 710 and coordinates storage and processing of the data. It should be borne in mind that the controllers, and indeed various circuitry described herein, may be defined by hardware circuitry, firmware or software. Moreover, the controllers may be separate pieces of hardware, as shown in FIG. 16, or integrated into one piece of hardware. The particular protocols for imaging sequences, for example, will generally be defined by code executed by the system controllers. Moreover, initial processing, conditioning, filtering, and other operations required on the measurement data acquired by the scanner may be performed in one or more of the components depicted in FIG. 16. For example, as described below, detector elements will produce analog signals representative of depletion of a charge in photodiodes positioned at locations corresponding to pixels of the data acquisition detector. Such analog signals are converted to digital signals by electronics within the scanner, and are transmitted to data acquisition controller 710. Partial processing may occur at this point, and the signals are ultimately transmitted to the system controller for further filtering and processing. System controller 712 is also coupled to an operator interface 714 and to one or more memory devices 716. The operator interface may be integral with the system controller, and will generally include an operator workstation for initiating imaging sequences, controlling such sequences, and manipulating measurement data acquired during imaging sequences. The memory devices 716 may be local to the imaging system, or may be partially or completely remote from the system. Thus, imaging devices 716 may include local, magnetic or optical memory, or local or remote repositories for measured data for reconstruction. Moreover, the memory devices may be configured to receive raw, partially processed or fully processed measurement data for reconstruction. A monitor (not shown) may also be connected to operator interface 714 to allow viewing of scan data, reconstruction data, or otherwise processed data. System controller 712 or operator interface 714, or any remote systems and workstations, may include software for image processing and reconstruction. As will be appreciated by those skilled in the art, such processing of CT measurement data may be performed by a number of mathematical algorithms and techniques. For example, conventional filtered back-projection techniques may be used to process and reconstruct the data acquired by the imaging system. Other techniques, and techniques used in conjunction with filtered back-projection may also be employed. A remote interface 718 may be included in the system for transmitting data from the imaging system to such remote processing stations or memory devices. FIG. 17 illustrates a portion of an acquisition subsystem 800 for use in an object detection system, such as, for example, a computed tomography (CT) scanner such as the scanner 702 of FIG. 16. Specifically, FIG. 17 illustrates an X-ray tube head 840. A multilayer optic 10 is incorporated within the system 800. The alternating lower and higher index of refraction materials with concurrent high and low X-ray absorption properties, respectively, in contiguous layers, of a multilayer optic 10 utilize the principle of total internal reflection of electromagnetic radiation. In operation, a filament, such as, for example, a tungsten filament within the cathode 742, is heated to emit an electron beam 726, which is directed towards an anode 744 in which resides the target 724. Thus, diverging X-ray beams emanating from the target 724 enter the input face 12 and are redirected into beams of photons 734 exiting the output face 14. The multilayer optic 10 can be formed to output any desired beam. The multilayer optic 10 can be positioned exterior or interior to the window 748. The multilayer optic 10 is shown in both locations in FIG. 17 for ease of illustration. The multilayer optic 10 may be formed in such a way as to produce a desired shaped beam of X-rays at energies of 20 keV and above depending on the application, such as the beams of photons 734 shown in FIG. 17. The multilayer optic 10 for producing a limited cone beam of X-rays can be formed as described above with reference to FIGS. 2-5, with the exception being that the output face 14 is formed closer to an input face 12, i.e., positioned prior to the region where the photons are redirected into parallel rays. The input face 12 may be flat or it may be curved to accept as much of the source cone of X-rays from the target 724. This allows the input X-ray beams to be shaped into a desired shaped beam 734. A third-generation CT imaging system where the X-ray tube and detector rotate about the imaging volume has been described herein; however, the optic is equally applicable to alternate configurations of third-generation technology, for example, with industrial CT configurations where the X-ray source and detector are held fixed and a stage rotates the object during data acquisition. Referring specifically to FIG. 18, there is shown a pair of optic devices 10a, 10b. Each of these optic devices 10a, 10b is similar to the optic device 10 described with specific reference to FIGS. 2-5. The difference between the optic devices 10a, 10b is that one is formed to pass higher X-ray energies, while the other is formed to pass lower X-ray energies. Shaping or filtering the source spectrum with the optic devices 10a, 10b offers the promise of rapidly producing spectral shapes with sharp higher-energy cutoffs on a sub-view basis, which improves material separation sensitivity and can eliminate most registration issues. The capabilities for producing spectra with desired spectral shapes and for producing them on a fast time scale makes such optic devices particularly useful for multi-energy imaging. K-edge filters may be utilized to provide a sharp low-energy cut-off for each optic 10a, 10b. One embodiment includes vapor depositing the K-edge filter directly onto either end of the optic 10a, 10b. Alternatively, the K-edge filter may be formed as a separate foil aligned with the output or input of the optic 10a, 10b. Then each optic 10a, 10b would have its own different K-edge filter either integral to the optic or separate from it. The optic devices 10a, 10b, which as illustrated may be in a stacked arrangement, are in optical communication with the target 724 of the X-ray tube head 840 of the acquisition subsystem 800 (FIG. 17). Specifically, X-rays 733 formed by striking electron beams at focal spots 725 on the target 724 are propagated from the focal spots 725 toward the input faces 12 of the optic devices 10a, 10b. Alternatively, the focal spots 725 may each be within separate individual target spots as opposed to the single continuous target spot 724 or on separate non-contiguous targets. The X-rays 733 are then focused by the optical devices 10a, 10b, as described above, and exit the output faces as redirected X-rays 734. This geometry can be replicated to produce an array of pairs of such spots, where a distributed array of x-ray source spots is to be utilized. To assist in separating high-and low-energy signals, a number of options are possible. One such arrangement uses an optic device with a separate K-edge filter to produce two signals whose energy distributions are different from each other. This is done by taking an image with one optic device and then retaking the image with both the optic device and a K-edge filter to eliminate low energy photons. Subtracting the two, appropriately normalized, signals results in a signal with predominantly low energies, while the signal produced by the combined optic device and K-edge filter produces a signal with relatively higher energy photons. Alternatively, two optic devices could be used in conjunction with at least one K-edge filter. The two optic devices are made of materials that result in x-ray redirection and transmission of two photon energy ranges that may or may not overlap. Taking an image with these two optic devices, repeating with the optic devices and a K-edge filter that blocks the energies from the optic device that transmits the lower energies, and subtracting the two, appropriately normalized, images will result in an image derived from only the low energies passed by the optic that transmitted the lower energies. The lower energy spectrum image could be obtained by subtracting this higher energy spectrum image, appropriately normalized, from the image formed with photons from the combined two optic devices and K-edge filter. To create a sharper low energy cut-off in the lower energy image, a second K-edge filter could be included that blocks the lowest energy photons from that optic. Another option that can provide even greater energy separation between the signals is to couple the optic devices to separate targets at different accelerating potentials and taking sequential images with x rays emitted by each accelerating potential/optic combination. To obtain the image sets produced by the different energy distributions quickly and with the best possible statistical definition, a filter wheel 775 (FIG. 19) may be used for sequential filtering of the signals. For example, to generate a dual-energy photon distribution, the filter wheel 775 could be made to include portions 780 that are opaque to all photons and windows 782 that are transparent to all the X rays. The windows 782 are only illustrated partially around the filter wheel 775 for ease of illustration purposes only. Alternatively, the windows 782 could be covered by appropriate filtering material, such as that needed to block the low-energy X rays from the higher-energy spectrum when two optic devices are used for imaging. By rotating the filter wheel 775, a portion 780 can be positioned between the optic device 10a and the detector, thereby blocking all the X rays transmitted by the optic 10a from reaching the detector. Simultaneously, a window 782 can be positioned between the other optic device 10b and the detector, allowing all the X rays transmitted by optic 10b to reach the detector. Then, the filter wheel 775 is rotated to allow a window 782 to be positioned between the optic device 10a and the detector 750, and a portion 780 is positioned between the optic device 10b and the detector 750, allowing X rays from only optic device 10a to be received by the detector. The optic devices 10a, 10b are fabricated such that each filters out certain X-ray energy levels. Specifically, each optic device 10a, 10b is fabricated from appropriate optic materials that selectively redirect X-rays of a certain energy level in the optic by predominantly total internal reflection. The refractive indices of the materials used to fabricate the optic devices determine the high-energy cutoff, establishing the emitted spectrum high-energy endpoint. As described previously, the optic devices include alternating high and low refractive index materials deposited in layers, with individual layers being in the nanometer thickness range. Each layer at the input face 12 of an optic device 10 may be curved to a different degree to capture a large source angle, such as, forty-five degrees or more, and redirect the X-rays into a tightly collimated fan-shaped beam. As described previously, combining some sort of low energy x-ray filtering, such as K-edge filters, with the higher-energy filtration of the optic devices 10a, 10b, different spectral shapes can be produced effectively. The low energy filtering can take the form of stand-alone foils that can be placed in the conventional post-optic emission position, or between the source focal spot and the optic devices. Alternatively, these low-energy filters can be vapor-deposited or chemically plated onto either the input or output ends of each optic. Another possibility is to incorporate the filter internally to the optic devices as a dopant in the high refractive index materials. Yet another method for filtering the lower energies from an optic's transmission is to manufacture the optic with selectively rough interfaces. The surface roughness will cause the lowest energies to be scattered, while not affecting the reflection of the higher energies. Additionally, a method for internally filtering includes choosing different materials in the optic device that determine the critical angle for total internal reflection, wherein the critical angle determines the highest X-ray energies transmitted by the optic device. The energy spectra produced by these optics-filter alternatives can be shaped considerably different from the source's inherent Bremsstrahlung emission, with much sharper high and low-energy cutoffs. Another topology for creating two different energy distribution images is shown in FIG. 20 involving splicing together two halves 10′, 10″ of two different optics to form a single optic device 10c. The creation of a single optic device 10c of this type potentially reduces the distance between the centroids of the two target spots 725 and so allows a smaller intrinsic beam spot size to be used, more efficiently utilizing the target emission, reducing target loading, and improving image registration. Switching from one beam to the other could be achieved with a filter wheel such as filter wheel 775. The difference between the optic devices 10′, 10″ is that one transmits higher X-ray energies 734′, while the other transmits lower X-ray energies 734″. Shaping or filtering the source spectrum with the optic devices 10′, 10″ and appropriately incorporated lower energy filtration of each optic spectrum offers the promise of rapidly producing spectral shapes with sharp high and low energy cutoffs on a sub-view basis, which improves material separation sensitivity and can eliminate most registration issues. The capabilities for producing spectra with desired spectral shapes and on a fast time scale makes such optic devices particularly useful for multi-energy imaging. In the acquisition subsystem 800 (FIG. 17), the optic device 10c, is in optical communication with the target 724 of the X-ray tube head 840. Specifically, X rays 733 formed by striking electron beams at focal spot 725 on the target 724 are propagated from the focal spot 725 toward the input faces 12′, 12″, respectively, of the two halves 10′, 10″ of the optic device 10c. The X rays 733 are then focused by the two halves 10′, 10″, as described above with regard to the two optic devices 10a, 10b (FIG. 18), and exit the output faces as redirected higher and lower energy X-rays 734′, 734″. Yet another topology involves even closer spatial integration of the lower and higher energy optic regions. A single optic device can be made with multiple different sets of high and low refractive index materials, allowing one optic to produce multiple energy distributions simultaneously. Additionally, in an optic that produces a dual-energy beam, for example, the portion of the optic device used to produce the lower energy beam could have its corresponding low energy filter (e.g., a K-edge filter) incorporated internally as a dopant. Then the filter wheel would simply contain alternating regions of open windows and the K-edge filters for the optic layer that transmit the higher energy X rays. As described previously, taking sequential images with first the K-edge filter on the filter wheel in line with the optic, then with the open window on the filter wheel in line with the optic, and then subtracting the appropriately normalized images, dual energy images can be created with spatially coincident spots having essentially identical spot shapes (averaged over the nanometer layer structure of the optic). As noted previously, the K-edge filters may be incorporated as dopants. As an example of how such doping can be accomplished, suppose the K-edge of nickel is used to block the lower energy photons and the high refractive index layers are made of all one material, LiH. Then the LiH layer could be doped with Ni by co-depositing the lithium hydride and nickel simultaneously, with the minimum amount of nickel over the length of the optic needed to block the desired lower energies. The required nickel concentration can be calculated from the overall optic length, the X-ray transmitting layer thickness, and the desired degree of lower energy blocking. For an optic on the order of millimeters long, the number of nickel atoms likely would be three or more orders of magnitude lower than the number of lithium hydride molecules. The dual-energy system described with reference to FIGS. 18-20 will experience fewer registration issues in the image reconstruction projections. By arranging a pair of optic devices 10a, 10b together with a rapidly actuated shutter, such as the filter wheel 775, each optic device can be sequentially exposed, thereby controlling which spectrum is emitted at a given time. Such an arrangement can provide alternating spectral shapes on a sub-millisecond timescale, which will mitigate registration differences between the projection sets for the two energies. In another topology, two optic devices may be used, one being focused onto one X-ray focal spot and shapes the X-ray spectrum in a desired manner, such as producing a lower energy spectrum. The second optic is focused onto a second X-ray focal spot and shapes the X-ray spectrum to produce a higher energy spectrum. Each optic device redirects its output to probe the same volume of space. The range of X-ray energies incident on the optic devices can be rapidly changed by appropriate gridding of either X-ray focal spot, or by redirecting a single beam to multiple X-ray focal spot locations. For example, to probe the scanned object with a low-energy spectrum, the opposite X-ray focal spot is gridded. If the two X-ray focal spot locations utilize the same accelerating potential, the optic devices can be made to filter the spectra as desired. Alternatively, the X-ray focal spot locations may utilize different accelerating potentials and a similar optic device to affect the spectral differences. In yet another embodiment, both accelerating potential and optic device characteristics can be altered to shape the spectral characteristics of the X-ray beam. Furthermore, beam filters can be used with the optic to further shape the spectra as desired. Any of the approaches presented herein may involve replication to provide multi-energy capability for a distributed array of x-ray spots. Such a multi energy system can be used in applications other than computed tomography. For example, such a system can be used in X-ray diffraction, as well as standard X-ray projection imaging. By using quasi-monochromatic X-rays, the optics can maintain required energy intensity, allowing the scanning speed to remain high. While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. For example, while the embodiments of the invention described with specific reference to FIGS. 17-20 refer to an optic device 10, 10a, 10b, 10c, such description was for ease of description only and it should be appreciated that any of the multilayer optic devices described herein can be incorporated as appropriate. Furthermore, while single energy and dual-energy techniques are discussed above, the invention encompasses approaches with more than two energies. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.
	abstract	The present invention provides an apparatus for detecting and/or repositioning annulus spacers used to maintain the position of a pressure tube withm a calandria tube of a nuclear reactor. The method comprises the steps of: vibrationally isolating a section of the pressure tube; vibrating the wall of said pressure tube within said isolated section; detecting vibration of the wall at a minimum of two axial positions within said isolated sections; and detecting the reduction in vibration level of the wall at one or more of said axial positions in comparison to the remaining axial positions. The apparatus comprises a tool head to be inserted into the pressure tube, the tool head comprising a first end and a second and a clamping block m each of said ends. The clamping blocks are used to vibrationally isolate a section of the pressure tube located between said ends. The apparatus also comprises piezo-actuators operable to vibrate said pressure tube; and accelerometers used for measuring vibration of said pressure tube.
	summary
	description	If an Application Data Sheet (ADS) has been filed on the filing date of this application, it is incorporated by reference herein. Any applications claimed on the ADS for priority under 35 U.S.C. §§119, 120, 121, or 365(c), and any and all parent, grandparent, great-grandparent, etc. applications of such applications, are also incorporated by reference, including any priority claims made in those applications and any material by reference, to the extent such subject matter is not inconsistent herewith. The present application is related to and/or claims the benefit of the earliest available effective filing date(s) from the following listed application(s) (the “Priority Applications”), if any, listed below (e.g., claims earliest available priority dates for other than provisional patent applications or claims benefits under 35 USC §119(e) for provisional patent applications, for any and all parent, grandparent, great-grandparent, etc. applications of the Priority Application(s)). In addition, the present application is related to the “Related Applications,” if any, listed below. For purposes of the USPTO extra-statutory requirements, the present application constitutes a divisional of U.S. patent application Ser. No. 12/290,883 now U.S. Pat. No. 8,721,810, entitled SYSTEM AND METHOD FOR ANNEALING NUCLEAR FISSION REACTOR MATERIALS, naming Charles E. Ahlfeld, John Rogers Gilleland, Roderick A. Hyde, David G. McAlees, Jon David McWhirter, Ashok Odedra, Clarence T. Tegreene, Joshua C. Walter, Kevan D. Weaver, Charles Whitmer, Lowell L. Wood, Jr., and George B. Zimmerman as inventors, filed 3 Nov. 2008, and which is a continuation of U.S. patent application Ser. No. 12/284,338 now U.S. Pat. No. 8,529,713, entitled SYSTEM AND METHOD FOR ANNEALING NUCLEAR FISSION REACTOR MATERIALS, naming Charles E. Ahlfeld, John Rogers Gilleland, Roderick A. Hyde, David G. McAlees, Jon David McWhirter, Ashok Odedra, Clarence T. Tegreene, Joshua C. Walter, Kevan D. Weaver, Charles Whitmer, Lowell L. Wood, Jr., and George B. Zimmerman as inventors, filed 18 Sep. 2008. U.S. patent application Ser. No. 12/290,894, entitled SYSTEM AND METHOD FOR ANNEALING NUCLEAR FISSION REACTOR MATERIALS, naming Charles E. Ahlfeld, John Rogers Gilleland, Roderick A. Hyde, David G. McAlees, Jon David McWhirter, Ashok Odedra, Clarence T. Tegreene, Joshua C. Walter, Kevan D. Weaver, Charles Whitmer, Lowell L. Wood, Jr., and George B. Zimmerman as inventors, filed 3 Nov. 2008, is related to the present application. The United States Patent Office (USPTO) has published a notice to the effect that the USPTO's computer programs require that patent applicants reference both a serial number and indicate whether an application is a continuation, continuation-in-part, or divisional of a parent application. Stephen G. Kunin, Benefit of Prior-Filed Application, USPTO Official Gazette Mar. 18, 2003. The USPTO further has provided forms for the Application Data Sheet which allow automatic loading of bibliographic data but which require identification of each application as a continuation, continuation-in-part, or divisional of a parent application. The present Applicant Entity (hereinafter “Applicant”) has provided above a specific reference to the application(s) from which priority is being claimed as recited by statute. Applicant understands that the statute is unambiguous in its specific reference language and does not require either a serial number or any characterization, such as “continuation” or “continuation-in-part,” for claiming priority to U.S. patent applications. Notwithstanding the foregoing, Applicant understands that the USPTO's computer programs have certain data entry requirements, and hence Applicant has provided designation(s) of a relationship between the present application and its parent application(s) as set forth above and in any ADS filed in this application, but expressly points out that such designation(s) are not to be construed in any way as any type of commentary and/or admission as to whether or not the present application contains any new matter in addition to the matter of its parent application(s). If the listings of applications provided above are inconsistent with the listings provided via an ADS, it is the intent of the Applicant to claim priority to each application that appears in the Priority Applications section of the ADS and to each application that appears in the Priority Applications section of this application. All subject matter of the Priority Applications and the Related Applications and of any and all parent, grandparent, great-grandparent, etc. applications of the Priority Applications and the Related Applications, including any priority claims, is incorporated herein by reference to the extent such subject matter is not inconsistent herewith. The present application relates to nuclear fission materials, and systems, methods, apparatuses, and applications related thereto. Illustrative embodiments provide systems, methods, apparatuses, and applications related to annealing nuclear fission reactor materials. The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description. In the following detailed description, reference is made to the accompanying drawings, which form a part hereof. In the drawings, similar symbols typically identify similar components, unless context dictates otherwise. The illustrative embodiments described in the detailed description, drawings, and claims are not meant to be limiting. Other embodiments may be utilized, and other changes may be made, without departing from the spirit or scope of the subject matter presented here. First, an overview will be set forth regarding illustrative embodiments, non-limiting examples of components that may be annealed, and annealing effects on components of nuclear fission reactors. Next, illustrative methods will be explained. Then, illustrative apparatuses will be explained. Overview Illustrative embodiments provide systems, methods, apparatuses, and applications related to annealing nuclear fission reactor materials. In some embodiments, illustrative methods are provided for annealing nuclear fission reactor materials, such as without limitation a nuclear fission reactor core or fuel assembly or components thereof. For example, referring to FIG. 1A an illustrative method 100 is provided for annealing at least a portion of at least one metallic component of a nuclear fission fuel assembly of a nuclear fission reactor. Referring to FIG. 2A, an illustrative method 200 is provided for annealing at least a portion of at least one component of a reactor core of a nuclear fission reactor. Referring to FIG. 3A, an illustrative method 300 is provided for treating at least a portion of at least one component of a reactor core of a nuclear fission reactor. Referring to FIG. 4A, a method 400 is provided for producing an annealing effect. Referring now to FIG. 5A, a method 500 is provided annealing at least a portion of at least one component of a nuclear fission reactor core. Details will be set forth further below. The illustrative methods, systems, and apparatuses described herein may be used for annealing any irradiated component of a core of any type of nuclear fission reactor as desired and without limitation. A brief overview of illustrative reactor core components that may be annealed will now be set forth by way of non-limiting examples. It will be understood that the following examples of components that may be annealed are described by way of illustration only and not limitation. For example, components of a reactor core assembly of a pressurized water reactor may be annealed. Referring now to FIG. 6A, an illustrative pressurized water reactor 600, given by way of non-limiting example, includes a reactor pressure vessel 602 that contains a reactor core assembly 604 in which nuclear fission occurs within the thermal spectrum. Each primary reactor coolant loop 606 includes its own heat exchanger 608, such as a steam generator, and reactor coolant pump 610. A pressurizer 612 is connected to one of the primary reactor coolant loops 610 and controls reactor coolant pressure, typically through use of heaters (not shown) that control temperature of the reactor coolant in the pressurizer 612. The pressurizer 612 helps maintain pressure of the reactor coolant sufficiently high, such as around 2250 psig or so, to help prevent formation of steam in the primary system. The reactor coolant pumps 610 pump reactor coolant through cold legs 614 into the reactor pressure vessel 602. The reactor coolant is heated by heat from nuclear fission occurring in the reactor core assembly 604. Reactor coolant exits the reactor pressure vessel 602 through hot legs 616 and enters the steam generators 608. Heat is transferred from the reactor coolant to secondary coolant in U-tubes (not shown) in the steam generators, thereby generating steam that can be used to drive turbines (not shown), such as electrical turbine generators, engines, or the like. Referring additionally to FIG. 6B, a basic unit of the reactor core assembly 604 is a nuclear fission fuel element 618, such as a fuel rod or fuel pin. Nuclear fission fuel material, such as uranium dioxide, is pressed into cylindrical pellets 620 that are sintered, ground to desired dimensions, and sealed, such as by welding shut, in cladding 622, such as an alloy of zirconium (like zircalloy). Flow of reactor coolant, at typical operating temperatures of around 600° F., through the fuel assemblies 626 helps maintain temperature of the zircalloy cladding 622 nominally below around 700° F. An annular space 624 typically is provided between the pellets 620 and the cladding 622. Referring additionally to FIG. 6C, nuclear fission fuel elements 618 are assembled into a fuel assembly 626. In a typical fuel assembly 626, the nuclear fission fuel elements 618 are assembled into a square array that is held together by spring clip grid assemblies 628 and by nozzles 630 and 632 at the top and bottom, respectively, of the nuclear fission fuel assembly 626. An open structure of the nuclear fission fuel assembly 626 defines reactor coolant channels that permit flow of reactor coolant (vertically and horizontally). The nuclear fission fuel assembly 626 may also include provision for passage of one or more control rods 634 that contain neutron absorbing material. Referring additionally to FIG. 6D, the reactor core assembly 604 includes several fuel assemblies 626. The reactor core assembly 604 also includes cooling components, such as baffles 636 and the reactor coolant channels that direct reactor coolant to, through, and from the fuel assemblies 626. The reactor core assembly 604 also includes structural members that form the fuel assemblies 626 into the reactor core assembly 604, such as core support columns 638, an upper core plate 640, a lower core plate 642, a core barrel 644, and the like. By way of further examples, components of a reactor core assembly of a fast breeder reactor may be annealed. Referring now to FIG. 7A, a liquid metal fast breeder reactor 700 uses a liquid metallic reactor coolant, such as sodium, lead, lead-bismuth, or the like, to cool a reactor core assembly 702. The reactor coolant is pumped by a reactor coolant pump 704 in a primary reactor coolant loop 706. A heat exchanger 708 transfers heat from the reactor coolant to intermediate loop coolant (which may be the same fluid as the reactor coolant in the primary reactor coolant loop 706) that is pumped by an intermediate coolant pump 710 in an intermediate coolant loop 712. A heat exchanger 714, such as a steam generator, generates steam that can be used to drive one or more turbines 716, such as electrical turbine generators, engines, or the like. A condenser 718 condenses steam that is exhausted by the turbine 716. Condensate from the condenser 718 is pumped by a feedwater pump 720 to the heat exchanger 714. Referring additionally to FIG. 7B, a basic unit of the reactor core assembly 702 is a nuclear fission fuel element 722, such as a fuel rod or fuel pin. A portion of the nuclear fission fuel element 722 includes fissile material 724, such as 239Pu, 233U, or 235U. Because the liquid metal fast breeder reactor 700 is a breeder reactor, the reactor core assembly 702 typically produces as much or more fissile material than it consumes. To that end, the nuclear fission fuel element 722 also includes portions of fertile material 726, such as 238U or 232Th. In one approach, the fissile material 724 and the fertile material 726 typically are pressed into oxide pellets that are sealed, such as by welding shut, in cladding 728, such as stainless steel. Referring additionally to FIG. 7C, nuclear fission fuel elements 722 are assembled into a fuel assembly 730. In a typical fuel assembly 730, the nuclear fission fuel elements 722 are assembled into an assembly that is held together by a handling fixture 732 and by a grid plate 734. An open structure of the nuclear fission fuel assembly 730 defines reactor coolant channels that permit flow of reactor coolant. Referring additionally to FIG. 7D, the reactor core assembly 702 includes several fuel assemblies 730. The reactor core assembly 702 also includes cooling components, such as throttling inserts that can throttle reactor coolant to the fuel assemblies 730. The reactor core assembly 702 also includes structural members that form the fuel assemblies 730 into the reactor core assembly 702, such as an upper core support plate 738, a lower core support plate 740, a core barrel 742, and the like. The reactor core assembly 702 is contained within a reactor pressure vessel 744. In some other arrangements and referring additionally to FIG. 7E, a pool-type liquid metal fast breeder reactor 700A uses a pool of liquid metallic reactor coolant, such as sodium, lead, lead-bismuth, or the like, in a reactor pressure vessel 744A to cool a reactor core assembly 702A. The reactor pressure vessel 744A contains the pool of reactor coolant, the reactor core assembly 702A, the reactor coolant pump 704, and the heat exchanger 708. Another example of a fast breeder reactor is a gas cooled fast breeder reactor. Referring now to FIG. 7F, a gas cooled fast breeder reactor 750 includes a reactor pressure vessel 744B that contains a reactor core assembly 702B that is cooled by a gaseous reactor coolant, such as helium, that is circulated by a gaseous coolant circulator 752. The gaseous reactor coolant is circulated through the reactor core assembly 702B and is heated, and heat is transferred from the gaseous reactor coolant in a heat exchanger 754, such as a steam generator. Referring additionally to FIG. 7G, the reactor core assembly 702B includes nuclear fission fuel elements that are assembled into fuel assemblies 730B by structural components, such as a grid plate 734B and a grid support structure. The nuclear fission fuel elements and the fuel assemblies 730B are generally similar to the nuclear fission fuel elements 722 (FIGS. 7B and 7C) and the fuel assemblies 730 (FIG. 7C), with the difference that the nuclear fission fuel elements of the gas cooled fast breeder reactor 750 have surfaces that are roughened to provide increased surface area for heat transfer to the gaseous reactor coolant (that is, a thermally conductive member). Referring now to FIGS. 7A-7G, in some arrangements the liquid metal fast breeder reactors 700 (FIGS. 7A-7D) and 700A (FIG. 7E) and the gas cooled fast breeder reactor 750 (FIGS. 7F-7G) may entail conventional nucleonics that involve reprocessing of breeder blankets. In some other arrangements, liquid metal fast breeder reactors and gas cooled fast breeder reactors may entail nucleonics in which a nuclear fission deflagration wave is initiated and propagated. Initiation and propagation of a nuclear fission deflagration wave is discussed in U.S. patent application Ser. No. 11/605,943, entitled AUTOMATED NUCLEAR POWER REACTOR FOR LONG-TERM OPERATION, naming RODERICK A. HYDE, MURIEL Y. ISHIKAWA, NATHAN P. MYHRVOLD, AND LOWELL L. WOOD, JR. as inventors, filed 28 Nov. 2006, the contents of which are hereby incorporated by reference. Reactor materials, such as without limitation components, like metallic components, of reactor cores discussed in the illustrative non-limiting examples set forth above, can experience exposure to neutrons with energy sufficient to create degradation, such as defects, in the material on the atomic and molecular level. Radiation damage to structural materials (measured in dislocations per atom (dpa)) is primarily reflective of exposure to neutrons with energies greater than 1 MeV. Damage from neutron exposure tends to cause radiation hardening, such that the ductile-to-brittle transition temperature of the material increases. Moreover, in a nuclear fission deflagration wave fast breeder reactor, reactor core materials may experience a high level of fluence due to exposure to high energy (that is, fast spectrum) neutrons over a prolonged time (due to slow propagation velocity of the nuclear fission deflagration wave). For some classes of structural materials (such as ferritic/martensitic steels), it is known that some radiation damage can be removed by heating the material to greater than around 40% or so of its melting point and holding the material at that temperature for a pre-determined amount of time—that is, annealing the material. This removal of radiation damage results from relieving stress by, primarily, thermally inducing migration of crystalline defects to grain boundaries. When these defects are in the form of dislocations, these dislocation points act as localized stress risers within the crystal. Increasing the temperature of the material increases the mobility of the dislocations, thereby enabling the dislocation to migrate to a grain boundary where the stress is relieved. Subsequent cooling (e.g., quenching) for a predetermined amount of time followed by an increase in temperature can temper the material, thereby “locking in” its desired metallurgical qualities. Counter to this effect is creep (that is, physical geometry change of the bulk material due to applied stresses such as fuel element internal pressure from fission products). The rate of creep increases with increasing temperature for a given stress. The creep rate in conjunction with internal vs. external pressures on the fuel element and/or fuel assemblies may limit annealing temperatures and annealing times. The illustrative methods, systems, and apparatuses described herein can be used to treat or anneal components of reactor core assemblies or fuel assemblies, as desired for a particular application. To that end, it will be appreciated that the discussion set forth above regarding components of reactor core assemblies and components of fuel assemblies (that may be annealed by illustrative embodiments disclosed herein) is provided by way of non-limiting examples. That is, the components of reactor core assemblies and the components of fuel assemblies that may be treated or annealed by illustrative embodiments disclosed herein is not limited to those components of reactor core assemblies and components of fuel assemblies discussed above. To that end, any irradiated component of any reactor core assembly or any fuel assembly can be treated or annealed by illustrative embodiments disclosed herein. Illustrative Methods Now that an overview of illustrative methods and non-limiting examples of illustrative components that may be treated or annealed has been set forth, illustrative details of methods will now be discussed. Following are a series of flowcharts depicting implementations of processes. For ease of understanding, the flowcharts are organized such that the initial flowcharts present implementations via an overall “big picture” viewpoint and thereafter the following flowcharts present alternate implementations and/or expansions of the “big picture” flowcharts as either sub-steps or additional steps building on one or more earlier-presented flowcharts. Those having skill in the art will appreciate that the style of presentation utilized herein (e.g., beginning with a presentation of a flowchart(s) presenting an overall view and thereafter providing additions to and/or further details in subsequent flowcharts) generally allows for a rapid and easy understanding of the various process implementations. In addition, those skilled in the art will further appreciate that the style of presentation used herein also lends itself well to modular design paradigms. Referring now to FIG. 1A, the illustrative method 100 for annealing at least a portion of at least one metallic component of a nuclear fission fuel assembly of a nuclear fission reactor begins at a block 102. At a block 104 an annealing temperature range for at least a portion of at least one metallic component of a nuclear fission fuel assembly of a nuclear fission reactor is determined. At a block 106 at least the portion of the at least one metallic component of the nuclear fission fuel assembly is annealed within the annealing temperature range. The method 100 stops at a block 108. Illustrative details will be set forth below. It will be appreciated that any metallic component of any fuel assembly can be annealed by the method 100. For example, in some embodiments the at least one metallic component can include cladding, a cooling component, a structural member, a thermally conductive member, and/or nuclear fission fuel material. As discussed above, metals such as zircalloy and stainless steel also serve as the fuel element enclosure (that is, cladding). However, it will be appreciated that treatment by annealing as described herein can expand the types of materials that may be used for reactor core materials. To that end and given by way of non-limiting examples, metal from which the metallic component is made can include without limitation steel, oxide dispersion strengthened (ODS) steels, austenitic steels (304, 316), ferritic/martensitic steels refractory metal, a refractory metal alloy, a non-ferrous metal, a non-ferrous metal alloy, and/or a superalloy (such as Inconels, Zircaloys, and/or Hastelloys). In some embodiments, the annealing temperature range determined at the block 104 may be greater than a predetermined operating temperature range of the nuclear fission fuel assembly. For example, some illustrative pressurized water reactor fuel assemblies may have an operating temperature range between cold leg temperature TC of around 550° F. and hot leg temperature TH of around 650° F. (at a nominal coolant pressure of around 2,250 psig); an illustrative loop type liquid metal fast breeder reactor fuel assembly may have an operating temperature range between TC of around 700° F. and TH of around 1000° F.; and an illustrative gas cooled fast breeder reactor fuel assembly may have an operating temperature range between TC of around 600° F. and TH of around 1000° F. However, as will be described below, the annealing temperature range may be greater than the predetermined operating temperature range of the nuclear fission fuel assembly. In some embodiments, the annealing temperature range may be determined based upon radiation exposure of the at least one metallic component of the nuclear fission fuel assembly. For example, annealing temperature range may be based upon factors such as energy of the neutron spectrum to which the metallic component has been exposed. For example, for a given exposure time (such as may be measured in effective full power hours), exposure to a fast neutron spectrum (like in a fast breeder reactor) may result in more radiation damage than would exposure of the metallic component to a thermal neutron spectrum (like in a pressurized water reactor). As another example, for exposure to a given neutron spectrum (such as a thermal neutron spectrum or a fast neutron spectrum), exposure for a longer time (such as may be measured in effective full power hours) may result in more radiation damage than would exposure of the metallic component exposure for a shorter time. In such a case, a higher annealing temperature range (for a given annealing processing time) may be entailed for the case of longer exposure to the given neutron spectrum than would be entailed for the case of shorter exposure to the given neutron spectrum. Moreover, in some cases a portion of some components, such as without limitation, a middle of a fuel assembly or fuel element, may have a radiation exposure history that is different from a radiation exposure history of another portion of the component, such as without limitation, an edge region of the nuclear fission fuel assembly or fuel element. In such a case, a radiation damage gradient may exist along the component. Thus, an annealing temperature range may be different for one portion of the component to be annealed than for other portions of the component. In some other embodiments, the annealing temperature range may be determined based upon an operating temperature history during which the radiation occurred. It will be appreciated that lower temperature regions of a fuel assembly may suffer more radiation damage effects than higher temperature regions in the same fuel assembly. Moreover, in some cases a portion of some components, such as without limitation a middle of a fuel assembly or fuel element, may have an operating temperature history that is different from an operating temperature history of another portion of the component, such as without limitation an edge region of the nuclear fission fuel assembly or fuel element. In such a case, a radiation damage gradient may exist along the component. Thus, an annealing temperature range may be different for one portion of the component to be annealed than for other portions of the component. In some other embodiments, the annealing temperature range may be determined based upon an annealing history of the component to be annealed. That is, in some embodiments historical data regarding annealing temperature of past annealing operations for a metallic component may be used to determine future annealing temperature ranges for the metallic component. In some other embodiments, the annealing temperature range may be determined based upon material properties of the at least one metallic component of the nuclear fission fuel assembly. For example, in some embodiments a minimum temperature of the annealing temperature range may be at least around thirty percent of a melting point of the at least one metallic component of the nuclear fission fuel assembly. In one of the non-limiting examples discussed above, for stainless steel with a melting point of around 2,732° F., such a minimum temperature of the annealing temperature range can be around 820° F. In another non-limiting example discussed above, for Zircaloy with a melting point of around 3,362° F., such a minimum temperature of the annealing temperature range can be around 1,009° F. As another example, in some other embodiments, an annealing temperature within the annealing temperature range may be around forty percent of a melting point of the at least one metallic component of the nuclear fission fuel assembly. In one of the non-limiting examples discussed above, for stainless steel with a melting point of around 2,732° F., such an annealing temperature within the annealing temperature range can be around 1,093° F. In another non-limiting example discussed above, for Zircaloy with a melting point of around 3,362° F., such an annealing temperature within the annealing temperature range can be around 1,345° F. As another example, for some metallic components an annealing temperature within the annealing temperature range may be selected up to around 122° F. above an austenic temperature of the metal (as determined by the metal's percentage composition of carbon). Given by way of non-limiting examples, based upon such a material property an annealing temperature range could be between around 1360° F. and around 1482° F. for carbon compositions above around 0.8 percent. As a further non-limiting example, based upon such a material property an annealing temperature range could range between around 1360° F. and around 1482° F. for carbon compositions around 0.8 percent and vary substantially linearly up to an annealing temperature range between around 1657° F. and around 1774° F. for carbon compositions around 0 percent. However, in some embodiments, a maximum temperature of the annealing temperature range may be selected as desired to provide a predetermined safety margin below a melting point of at least one component of the nuclear fission fuel assembly. In some other embodiments, a maximum temperature of the annealing temperature range may be selected as desired to provide a predetermined safety margin below structural degradation of at least one component of the nuclear fission fuel assembly. As also discussed above, the creep rate in conjunction with internal vs. external pressures on the fuel element and/or fuel assemblies may affect annealing temperatures (and also annealing times). Annealing at least the portion of the at least one metallic component at the block 106 can be performed in various locations, as desired. For example, in some embodiments annealing at least the portion of the at least one metallic component can be performed in-place. However, the at least one metallic component need not be annealed in-place. For example and referring now to FIG. 1B, in some other embodiments the nuclear fission fuel assembly (that includes the component to be annealed) may be moved at a block 110 from an in-place location prior to annealing at the block 106. In one arrangement, annealing may be performed within a reactor core of the nuclear fission reactor. For example, the nuclear fission fuel assembly may be moved from its in-place location to another location within the reactor core where the annealing is to take place. In another arrangement, annealing may be performed external of a reactor core of the nuclear fission reactor. For example, the nuclear fission fuel assembly may be moved from its in-place location to a location external of the reactor core but still internal to the reactor pressure vessel where the annealing is to take place. As another example, the nuclear fission fuel assembly may be moved from its in-place location to a location external of the reactor pressure vessel where the annealing is to take place. In such a case, annealing may be performed on-site of the nuclear fission reactor or off-site from the nuclear fission reactor, as desired. In some embodiments and referring now to FIG. 1C, the nuclear fission fuel assembly may be moved to a location within a reactor core of the nuclear fission reactor after annealing. For example, the annealed fuel assembly may be moved to its in-place location or any other in-core location as desired after having been annealed in a location other than its in-place location. In some embodiments and referring to FIG. 1D, at a block 113 the nuclear fission fuel assembly may be re-oriented. Given by way of non-limiting example, the nuclear fission fuel assembly may be rotated 180 degrees for replacement in the reactor core. In such an arrangement, an end of the nuclear fission fuel assembly that was adjacent a cold leg inlet can be re-oriented for replacement in the reactor core adjacent a hot let outlet, and vice versa. That is, at the block 106 the nuclear fission fuel assembly can be turned “upside down” for replacement in the reactor core. In some embodiments, an entire nuclear fission fuel assembly need not be re-oriented at the block 113 in order for the nuclear fission fuel assembly to be considered re-oriented. For example, one or more fuel elements may be re-oriented within the nuclear fission fuel assembly in the same manner as described above (that is, rotated 180 degrees or turned “upside down”). It will be appreciated that the nuclear fission fuel assembly may be re-oriented before annealing or after annealing, as desired. In some other embodiments and referring to FIG. 1E, at a block 115 the nuclear fission fuel assembly may be reconfigured. Given by way of non-limiting example, components (or portions of components) of the nuclear fission fuel assembly, such as fuel elements (or portions of fuel elements), may be removed from their original position in the nuclear fission fuel assembly and replaced in a different position in the nuclear fission fuel assembly. For example, a portion of a fuel element that was located away from an end (such as toward a middle) of the fuel element can be removed and swapped with a portion of the fuel element that was located toward an end of the fuel element, thereby reconfiguring the fuel element and, as a result, the nuclear fission fuel assembly. It will be appreciated that the nuclear fission fuel assembly may be reconfigured before annealing or after annealing, as desired. As another example and referring to FIG. 1F, at a block 114 the nuclear fission fuel assembly may be moved from an in-place location after annealing. In such an arrangement, the annealed fuel assembly may be moved to another location other than its original in-place location after having been annealed in-place. Such relocations as described above may be performed as part of a fuel assembly utilization plan, if desired. Annealing at least the portion of the at least one metallic component of the nuclear fission fuel assembly within the annealing temperature range at the block 106 can be performed in various manners as desired for a particular application. For example and referring to FIG. 1G, in some embodiments annealing at least the portion of the at least one metallic component of the nuclear fission fuel assembly within the annealing temperature range at the block 106 can include adjusting operational parameters of the nuclear fission reactor to establish operating conditions of a region of the nuclear fission reactor containing the at least one metallic component within the determined annealing temperature range for a period of time selected to produce annealing of at least the portion of the at least one metallic component at a block 116. It will be appreciated that in some arrangements one or more portions of a component (such as portions that generate heat from nuclear fission during power range operations or that generate decay heat) that are hotter than other portions of the component may experience more annealing effect than the other portions of the component. In some embodiments and referring to FIG. 1H, adjusting operational parameters at the block 116 can include raising temperature of the region of the nuclear fission reactor containing the at least one metallic component from a predetermined operating temperature range of the reactor core toward the annealing temperature range at a block 118. Referring to FIG. 1I, adjusting operational parameters at the block 116 can include maintaining temperature of the region of the nuclear fission reactor containing the at least one metallic component substantially within the annealing temperature range at a block 120. Illustrative details regarding adjusting operational parameters to raise and/or maintain temperature and regarding selecting a period of time to produce annealing will be discussed below. Referring now to FIG. 1J, adjusting operational parameters at the block 116 can include providing heat from an external heat source at a block 122. It will be appreciated that an external heat source can be placed in thermal communication with a portion of the component or all or substantially all of the component, as desired for a particular application. In some arrangements, placing an external heat source in thermal communication with a portion of the component can help permit annealing one portion of the component. In such an arrangement, other portions of the component may experience less annealing effect than the portion in thermal communication with the external heat source. In some arrangements (such as in a reactor core that is shut down), the portion in thermal communication with the external heat source may experience an annealing effect and the other portions may experience little or no annealing effect. In some embodiments, the external heat source can include at least one electrical heat source. In some other embodiments, the external heat source can include at least one source of residual heat. For example, the residual heat can include decay heat. Given by way of non-limiting example, the decay heat may be generated by nuclear fission fuel material of one or more nuclear fission fuel elements of a fuel assembly that contains the metallic component being annealed and/or by nuclear fission fuel material of one or more nuclear fission fuel elements of one or more fuel assemblies that do not contain the metallic component being annealed. In some cases, such as when the metallic component to be annealed is cladding or metallic nuclear fission fuel material, the decay heat may be generated by nuclear fission fuel material of the nuclear fission fuel element that contains the metallic component being annealed. In some other embodiments, the external heat source can include a heating fluid. For example, a heating fluid can be placed in thermal communication with the metallic component to be annealed. In such an arrangement the temperature of the heating fluid can be established around a predetermined temperature to produce a desired annealing effect. The heating fluid, by way of non-limiting example, may include the reactor coolant as a major component of the heating fluid. In this example, the temperature of the heating fluid is brought to a desired temperature by any one or more of the methods discussed above and placed in thermal communication with the metallic component to be annealed. By way of another non-limiting example, the fluid may be substantially different from the reactor coolant and may include any non-reactive fluid, such as nitrogen, argon, helium, and/or combinations of these fluids, with the reactor coolant. The non-reactive fluid temperature may also be controlled by any one or more of the methods discussed above. In some other embodiments and referring to FIG. 1K, adjusting operational parameters at the block 116 can include substantially maintaining coolant flow rate at a block 124 and reducing an amount of heat transferred from the coolant at a block 126. In such an arrangement, in some embodiments the heat transfer that is reduced is the heat transfer from the reactor coolant to a heat exchanger. Given by way of non-limiting example, an amount of heat transferred from the coolant can be reduced by reducing an amount of fluid that exits a secondary side of a heat exchanger through which reactor coolant flows on a primary side. For example, a valve can be throttled toward a shut position on a secondary side of a primary-to-secondary heat exchanger in a pressurized water reactor, a pool-type liquid metal fast breeder reactor, or a gas-cooled fast breeder reactor. As a further example, a valve can be throttled toward a shut position on an intermediate side of an intermediate heat exchanger in a loop-type liquid metal fast breeder reactor. Given by way of further example, a heat load presented to any of the heat exchangers described above can be reduced. Similarly and referring to FIG. 1L, in some embodiments adjusting operational parameters at the block 116 can include substantially maintaining coolant flow rate at the block 124 and reducing an amount of heat transferred to the coolant at a block 128. In such an arrangement, in some embodiments the heat transfer that is reduced is the heat transfer from the nuclear fission fuel assembly containing the metallic component to be annealed to the reactor coolant. For example, if the heat transferred to a heat sink, such as a heat exchanger like a steam generator or the like, is reduced then the primary coolant temperature increases. This temperature increase of the reactor coolant in turn causes the temperature of the nuclear fission fuel assembly containing the metallic component to be annealed to rise for a given heat flux (that is, if decay heat is used as a heat source then the heat generation rate in the fuel will be roughly constant on short time scales). The nuclear fission fuel assembly then reaches a new temperature based on the new rate of heat rejection at the secondary loop or intermediate loop, as the case may be for a particular reactor application. To that end and given by way of non-limiting example, an amount of heat transferred to the coolant can be reduced by reducing an amount of fluid that exits a secondary side of a heat exchanger through which reactor coolant flows on a primary side. For example, a valve can be throttled toward a shut position on a secondary side of a primary-to-secondary heat exchanger in a pressurized water reactor, a pool-type liquid metal fast breeder reactor, or a gas-cooled fast breeder reactor. As a further example, a valve can be throttled toward a shut position on an intermediate side of an intermediate heat exchanger in a loop-type liquid metal fast breeder reactor. Given by way of further example, a heat load presented to any of the heat exchangers described above can be reduced. In other embodiments, referring to FIG. 1M adjusting operational parameters at the block 116 can include lowering, from a predetermined coolant flow rate, coolant flow rate into the region of the nuclear fission reactor containing the at least one metallic component at a block 130. For example, coolant flow rate can be lowered by throttling down a flow adjustment device, such as a valve. As another example, coolant flow rate can be lowered by shifting reactor coolant pump speed downward, such as from fast speed to slow speed, or by reducing the number of operating reactor coolant pumps. In other embodiments, referring to FIG. 1N adjusting operational parameters at the block 116 can include reversing direction of reactor coolant flow into the region of the nuclear fission reactor containing the at least one metallic component at a block 131. For example, in some arrangements reactor coolant flow can be reversed by appropriate positioning of cutoff valves and check valves. In some other arrangements, such as when the reactor coolant includes an electrically-conductive liquid reactor coolant, such as liquid metals, coolant flow can be reversed by an appropriate electrical device that can electrically control flow of electrically-conductive liquids. In other embodiments, referring to FIG. 1O adjusting operational parameters at the block 116 can include raising temperature of coolant entering the region of the nuclear fission reactor containing the at least one metallic component at a block 132. For example, reactivity level can be raised (such as, without limitation, by withdrawing control rods or otherwise removing neutron absorbing material) thereby increasing the amount of heat transferred from the nuclear fission fuel elements to the reactor coolant and, thus, raising temperature of reactor coolant for a given coolant flow rate. It will be appreciated that a negative temperature coefficient of reactivity (that is, negative αT) can help maintain inherent stability of the nuclear fission reactor in such cases. In some embodiments, referring to FIG. 1P adjusting operational parameters at the block 116 can include replacing at least a portion of a first reactor coolant having first heat transfer characteristics with second coolant having second heat transfer characteristics at a block 134. For example, in a liquid metal fast breeder reactor some or all of sodium reactor coolant may be replaced with lead reactor coolant or lead-bismuth reactor coolant; some or all of lead reactor coolant may be replaced with sodium reactor coolant or lead-bismuth reactor coolant; and some or all of lead-bismuth reactor coolant may be replaced with sodium reactor coolant or lead reactor coolant. Similarly, in a gas-cooled fast breeder reactor gaseous helium reactor coolant may be replaced with, given by way of non-limiting examples, gaseous argon, nitrogen, or supercritical carbon dioxide reactor coolant. In a pressurized water reactor, the liquid water reactor coolant may be replaced with, given by way of non-limiting examples, steam, inert gas, or the like. Referring now to FIG. 1Q, in some embodiments adjusting operational parameters at the block 116 can include raising pressure in the region of the nuclear fission reactor containing the at least one metallic component at a block 136. For example, pressure can be raised by a pressurizer (such as by energizing additional heaters in the pressurizer). Raising pressure can raise the temperature at which reactor coolant boils, thereby permitting raising temperature of the reactor coolant (and thus temperature of the metallic component to be annealed) without inducing local boiling in the reactor coolant in the region of the nuclear fission reactor containing the at least one metallic component. Referring now to FIG. 1R, in some other embodiments adjusting operational parameters at the block 116 can include lowering pressure in the region of the nuclear fission reactor containing the at least one metallic component. For example, pressure can be lowered by a pressurizer (such as by de-energizing heaters in the pressurizer). In some cases it may be desirable for local boiling to occur in the region of the nuclear fission reactor containing the at least one metallic component. Lowering pressure can lower the temperature at which reactor coolant boils, thereby permitting inducing local boiling in the reactor coolant in the region of the nuclear fission reactor containing the at least one metallic component. Because boiling is an isothermal process, substantially even temperature distribution can be maintained within the nuclear fission fuel assembly to be annealed. A substantially even temperature distribution may be maintained even in the event of increased heat generation rate of the heat generating material within the nuclear fission fuel assembly. Referring now to FIG. 1S, a determination may be made at a block 140 regarding when the at least one metallic component of the nuclear fission fuel assembly is to be annealed. The determination of when the at least one metallic component of the nuclear fission fuel assembly is to be annealed may be made at the block 140 in a variety of manners, as desired for a particular application. For example, in some embodiments and referring to FIG. 1T, determining when the at least one metallic component of the nuclear fission fuel assembly is to be annealed at the block 140 can include scheduling a predetermined time for annealing the at least one metallic component of the nuclear fission fuel assembly at a block 142. In some embodiments, the predetermined time may be scheduled during design of the reactor core assembly. In such a case, annealing may be considered to be part of reactor operation. As such, annealing may be performed for the reactor core assembly in bulk, if desired. Moreover, if applicable, bulk annealing of the reactor core assembly may be performed on a periodic schedule. In some other embodiments, determining when the at least one metallic component of the nuclear fission fuel assembly is to be annealed at the block 140 may be based upon history of the at least one metallic component. For example, determining when the at least one metallic component of the nuclear fission fuel assembly is to be annealed at the block 140 may be based upon an annealing history of the at least one metallic component. That is, in some embodiments historical data regarding time between annealing operations for a metallic component may be used to predict and schedule future annealing operations for the metallic component. As another example, determining when the at least one metallic component of the nuclear fission fuel assembly is to be annealed at the block 140 may be based upon an operational history of the nuclear fission fuel assembly. Given by way of non-limiting example, the operational history of the nuclear fission fuel assembly may include temperature history and/or radiation exposure or the like. In some embodiments, it may be known that materials typically are brought to annealing conditions at a certain operational time (such as may be measured in effective full power hours) or at a specific location within a reactor core assembly. In such a case, determining when to anneal the metallic component may be based on input from fluence history and temperature history. This fluence and temperature input may then be input into a calculation that can estimate (i) extent of radiation damage, if any; (ii) if annealing is needed; and (iii) in cases where annealing is needed, which annealing parameters are to be used. In some other embodiments and referring now to FIG. 1U, determining when the at least one metallic component of the nuclear fission fuel assembly is to be annealed at the block 140 may include testing materials that are indicative of the at least one metallic component of the nuclear fission fuel assembly at a block 144. In some embodiments and referring to FIG. 1V, testing materials that are indicative of the at least one metallic component of the nuclear fission fuel assembly at the block 144 can include testing at least a portion of the at least one metallic component of the nuclear fission fuel assembly at a block 146. Given by way of non-limiting example, referring to FIG. 1W testing materials that are indicative of the at least one metallic component of the nuclear fission fuel assembly at the block 146 may include testing for changes in material properties indicative of radiation damage at a block 148. For example, some illustrative material properties indicative of radiation damage may include electrical resistivity, physical dimensions, displacement response to physical stress, response to stimulus, speed of sound within material, ductile-to-brittle transition temperature, and/or radiation emission. In some embodiments and referring to FIG. 1X, annealing at least the portion of the at least one metallic component of the nuclear fission fuel assembly within the annealing temperature range is stopped at a block 150. That is, in some embodiments temperature may be returned from the annealing temperature range toward the predetermined operating temperature range. In some cases, temperature may be reduced to ambient (such as when a reactor is shut down, cooled down, and depressurized for maintenance or any other application as desired). A determination of when to stop annealing at least the portion of the at least one metallic component of the nuclear fission fuel assembly within the annealing temperature range at the block 150 may be made in any manner as desired for a particular application. For example, in some embodiments annealing may be stopped at the block 150 after a predetermined time period. Given by way of non-limiting example, the predetermined time period may be a function of temperature. For example, the predetermined time period may have an inverse relationship to the annealing temperature (that is, the lower the annealing temperature the longer the predetermined time period, and vice versa). In some other embodiments, the predetermined time period may be a function of changes in material properties indicative of radiation damage. For example, the predetermined time period may be directly (as opposed to inversely) proportional to changes in material properties indicative of radiation damage. In some cases, for a given annealing temperature the predetermined time period may be proportional to an amount or extent of radiation damage throughout the at least one metallic component. In some other cases, for a given annealing temperature the predetermined time period may be proportional to severity of radiation damage regardless of amount or extent of radiation damage throughout the at least one metallic component. In some embodiments the predetermined time period may be a function of radiation exposure. In such an arrangement, radiation damage to the at least one metallic component need not be determined. In some cases, for a given annealing temperature the predetermined time period may be proportional to energy of the neutron spectrum to which the at least one metallic component has been exposed. For example, a predetermined time period associated with exposure to a fast neutron spectrum (such as in a fast breeder reactor) may be longer than a predetermined time period associated with exposure to a thermal fission spectrum (such as in a pressurized water reactor). In some other cases, for a given annealing temperature the predetermined time period may be proportional to length of time of exposure. For example, longer exposure of a metallic component may entail a longer predetermined time period of annealing before stopping the annealing operation. However, it will be appreciated that exposure in a thermal reactor may entail additional exposure time to result in equivalent exposure time in a fast reactor. Referring now to FIG. 1Y, in some embodiments material properties of at least a portion of the at least one metallic component of the nuclear fission fuel assembly may be tested at a block 152 during annealing at the block 106. In such an arrangement, annealing at the block 106 is stopped at a block 150A responsive to testing material properties of at least a portion of the at least one metallic component of the nuclear fission fuel assembly. For example, results of testing of material properties can be monitored during annealing. When monitored results of a desired parameter have returned within desired levels, then annealing may be stopped. It will also be appreciated that, as discussed above, the creep rate in conjunction with internal vs. external pressures on the fuel element and/or fuel assemblies may limit annealing times (as well as temperatures). After annealing has been stopped at the block 150, it may be desirable in some embodiments to further treat that which has been annealed. To that end and referring now to FIG. 1Z, in some embodiments at a block 156 at least the portion of the at least one metallic component of the nuclear fission fuel assembly can be treated with post-annealing treatment. In some embodiments, post-annealing treatment can include quenching. Quenching can produce a phase of crystal types in the material of the metallic component, thereby hardening the material. To that end and referring to FIG. 1AA, in some embodiments post-anneal treating at least the portion of the at least one metallic component of the nuclear fission fuel assembly at the block 156 can include lowering temperature from the annealing temperature range to a quenching temperature range at a block 158. The quenching temperature range suitably is sufficiently low enough to cool the material that has been annealed. Given by way of non-limiting example, in some embodiments a suitable quenching temperature range can be around 200° C.-300° C. (392° F.-572° F.). However, any suitable quenching temperature range may be selected as desired for a particular application. For example, in some embodiments in which the reactor coolant is a liquid metal, it will be appreciated that the quenching temperature range should be sufficiently high enough for a liquid metal reactor coolant to remain in liquid phase. Given by way of non-limiting examples, sodium has a melting point of 207.9° F., lead-bismuth eutectic has a melting point of 254.3° F., and lead has a melting point of 327.5° F. In such arrangements, the quenching temperature range may be selected to be as low as desired to cool the material to perform quenching yet be high enough to keep the liquid metal reactor coolant in liquid phase. It will be noted that it may be desirable to lower temperature at the block 158 at a rate sufficient to achieve a quenching effect. To that end and referring to FIG. 1AB, in some embodiments lowering temperature to a quenching temperature range at the block 158 can include lowering temperature at a predetermined rate at a block 160. It will be appreciated that such a predetermined rate of lowering temperature may be selected as desired for a particular application and may depend on various factors, such as without limitation material to be quenched, amount of hardening desired, limitations on rate of lowering temperature due to reactor plant construction characteristics, and the like. If desired, in some embodiments a reactor plant may be shut down and cooled down and/or depressurized to help lower temperature toward the quenching temperature. In some other embodiments, replacement reactor coolant (for example, at a lower temperature than existing reactor coolant) may be introduced into the reactor core to help lower temperature toward the quenching temperature. In some other embodiments, post-annealing treatment can also include tempering after quenching. While quenching can produce a phase, tempering can grow the produced phase to any gaps in a grain boundary, thereby helping to relax grain boundary stress that may have developed during annealing and, as a result, toughening the material. To that end and referring to FIG. 1AC, in some embodiments post-anneal treating at least the portion of the at least one metallic component of the nuclear fission fuel assembly at the block 156 can also include raising temperature from the quenching temperature range to a tempering temperature range at a block 162. The quenching temperature range suitably is any temperature range as desired that is between the quenching temperature range and the annealing temperature range. In some embodiments the tempering temperature range may be higher than the operating temperature range. In some other embodiments the tempering temperature range may be lower than the operating temperature range. Referring now to FIG. 1AD, in some embodiments after annealing has stopped at the block 150 temperature may be established at an operational temperature range at a block 166, if desired. Referring now to FIG. 1AE, in some embodiments annealing at the block 106 can be performed after commencement of transition of reactivity condition of at least a portion of the nuclear fission reactor from a first state to a second state at a block 154. Given by way of non-limiting example, the first state can include power range operation and the second state can include a shut-down state. It will be appreciated that any number of metallic components of any number of fuel assemblies may be annealed, as desired for a particular application. For example, in some embodiments fewer than all nuclear fission fuel assemblies of a reactor core of the nuclear fission reactor can be annealed. In some other embodiments, substantially all nuclear fission fuel assemblies of a reactor core of the nuclear fission reactor can be annealed, as desired. Other illustrative methods will be described below. Referring now to FIG. 2A, the illustrative method 200 for annealing at least a portion of at least one component of a reactor core of a nuclear fission reactor begins at a block 202. At a block 204 an annealing temperature range (that is higher than a predetermined operating temperature range of the reactor core) for at least a portion of at least one component of the reactor core of a nuclear fission reactor is determined. At a block 206 at least the portion of the at least one component is annealed within the annealing temperature range. The method 200 stops at a block 208. Illustrative aspects will be described briefly below. While the method 100 (FIG. 1A) discloses annealing at least a portion of at least one metallic component of a nuclear fission fuel assembly of a nuclear fission reactor, the method 200 discloses annealing at least a portion of any component or components of a reactor core of a nuclear fission reactor. Thus, the method 200 can be used for annealing at least a portion of one or more reactor core components such as without limitation a nuclear fission fuel assembly, a reactor core cooling component, and/or a reactor core structural member, non-limiting examples of which are discussed above. In some arrangements, the method 200 can be used to anneal at least a portion of one or more components of a nuclear fission fuel assembly, such as without limitation cladding, a cooling component, a structural member, a thermally conductive member, and/or nuclear fission fuel material, non-limiting examples of which are discussed above. Moreover, the method 200 can be performed on any component of a reactor core—regardless of whether the component is metallic or not. Thus, annealing as disclosed by the method 200 can permit use in reactor cores of advanced materials, such as composite materials like SiC/SiC or the like. However, it will be appreciated that the method 200 may also be used for a one or more reactor core components that are made of metals—such as without limitation steel, oxide dispersion strengthened (ODS) steels, austenitic steels (304, 316), ferritic/martensitic steels refractory metal, a refractory metal alloy, a non-ferrous metal, a non-ferrous metal alloy, and/or a superalloy (such as Inconels, Zircaloys, and/or Hastelloys). Further, while the annealing temperature range for the method 100 (FIG. 1A) need not be higher than an operating temperature range, it will also be noted that the annealing temperature range determined at the block 204 is higher than the predetermined operating temperature range of the reactor core. With the exception of the differences noted directly above, other aspects of the method 200 are similar to aspects of the method 100 (FIG. 1A). To that end and for sake of brevity, aspects of the method 200 will be described briefly. As noted above, the annealing temperature range determined at the block 204 is higher than a predetermined operating temperature range of the reactor core. The discussion of optional arrangements of the method 100 (FIG. 1A) in which annealing temperature range is higher than a predetermined operating temperature range is applicable to the method 200. Thus, details of the annealing temperature range being higher than the operating temperature range need not be repeated for an understanding. However, aspects of the method 200 will be noted below for completeness. For example, in some embodiments, the annealing temperature range may be determined based upon any one or more factors such as radiation exposure of the at least one component, an operating temperature history during which the radiation occurred, and/or an annealing history of the component to be annealed. In some other embodiments, the annealing temperature range may be determined based upon material properties of the at least one component. For example, in some embodiments a minimum temperature of the annealing temperature range may be at least around thirty percent of a melting point of the at least one component. As another example, in some other embodiments, an annealing temperature within the annealing temperature range may be around forty percent of a melting point of the at least one component. In some embodiments, a maximum temperature of the annealing temperature range may be selected as desired to provide a predetermined safety margin below a melting point of at least one component. In some other embodiments, a maximum temperature of the annealing temperature range may be selected as desired to provide a predetermined safety margin below structural degradation of at least one component. Annealing at least the portion of the at least one component at the block 206 can be performed in various locations, as desired. For example, in some embodiments annealing at least the portion of the at least one component can be performed in-place. However, the at least one component need not be annealed in-place. For example and referring now to FIG. 2B, in some other embodiments the at least one component to be annealed may be moved at a block 210 from an in-place location prior to annealing at the block 206. In one arrangement, annealing may be performed within a reactor core of the nuclear fission reactor. For example, the at least one component may be moved from its in-place location to another location within the reactor core where the annealing is to take place. In another arrangement, annealing may be performed external of a reactor core of the nuclear fission reactor. For example, the at least one component may be moved from its in-place location to a location external of the reactor core but still internal to the reactor pressure vessel where the annealing is to take place. As another example, the at least one component may be moved from its in-place location to a location external of the reactor pressure vessel where the annealing is to take place. In such a case, annealing may be performed on-site of the nuclear fission reactor or off-site from the nuclear fission reactor, as desired. In some embodiments and referring now to FIG. 2C, the at least one component may be moved to a location within a reactor core of the nuclear fission reactor after annealing. In some embodiments and referring to FIG. 2D, at a block 213 the at least one component may be re-oriented. In some other embodiments and referring to FIG. 2E, at a block 215 the at least one component may be reconfigured. As another example and referring to FIG. 2F, at a block 214 the at least one component may be moved from an in-place location after annealing. Annealing at least the portion of the at least one component of the reactor core within the annealing temperature range at the block 206 can be performed in various manners as desired for a particular application. For example and referring to FIG. 2G, in some embodiments annealing at least the portion of the at least one component within the annealing temperature range at the block 206 can include adjusting operational parameters of the nuclear fission reactor to establish operating conditions of a region of the nuclear fission reactor containing the at least one component within the determined annealing temperature range for a period of time selected to produce annealing of the at least one metallic component at a block 216. In some embodiments and referring to FIG. 2H, adjusting operational parameters at the block 216 can include raising temperature of the region of the nuclear fission reactor containing the at least one component from a predetermined operating temperature range of the reactor core toward the annealing temperature range at a block 218. Referring to FIG. 2I, adjusting operational parameters at the block 216 can include maintaining temperature of the region of the nuclear fission reactor containing the at least one component substantially within the annealing temperature range at a block 220. Illustrative details regarding adjusting operational parameters to raise and/or maintain temperature and regarding selecting a period of time to produce annealing will be discussed below. Referring now to FIG. 2J, adjusting operational parameters at the block 216 can include providing heat from an external heat source at a block 222. In some embodiments, the external heat source can include at least one electrical heat source. In some other embodiments, the external heat source can include at least one source of residual heat. For example, the residual heat can include decay heat. In some other embodiments, the external heat source can include a heating fluid. In some other embodiments and referring to FIG. 2K, adjusting operational parameters at the block 216 can include substantially maintaining coolant flow rate at a block 224 and reducing an amount of heat transferred from the coolant at a block 226. Similarly and referring to FIG. 2L, in some embodiments adjusting operational parameters at the block 216 can include substantially maintaining coolant flow rate at the block 224 and reducing an amount of heat transferred to the coolant at a block 228. In other embodiments, referring to FIG. 2M adjusting operational parameters at the block 216 can include lowering, from a predetermined coolant flow rate, coolant flow rate into the region of the nuclear fission reactor containing the at least one component at a block 230. In other embodiments, referring to FIG. 2N adjusting operational parameters at the block 216 can include reversing direction of reactor coolant flow into the region of the nuclear fission reactor containing the at least one component at a block 231. In other embodiments, referring to FIG. 2O adjusting operational parameters at the block 216 can include raising temperature of coolant entering the region of the nuclear fission reactor containing the at least one component at a block 232. In some embodiments, referring to FIG. 2P adjusting operational parameters at the block 216 can include replacing at least a portion of a first reactor coolant having first heat transfer characteristics with second coolant having second heat transfer characteristics at a block 234. Referring now to FIG. 2Q, in some embodiments adjusting operational parameters at the block 216 can include raising pressure in the region of the nuclear fission reactor containing the at least one component at a block 236. Referring now to FIG. 2R, in some other embodiments adjusting operational parameters at the block 216 can include lowering pressure in the region of the nuclear fission reactor containing the at least one component. Referring now to FIG. 2S, a determination may be made at a block 240 regarding when the at least one component is to be annealed. The determination of when the at least one component is to be annealed may be made at the block 240 in a variety of manners, as desired for a particular application. For example, in some embodiments and referring to FIG. 2T, determining when the at least one component is to be annealed at the block 240 can include scheduling a predetermined time for annealing the at least one component at a block 242. In some other embodiments, determining when the at least one component is to be annealed at the block 240 may be based upon history of the at least one component. For example, determining when the at least one component is to be annealed at the block 240 may be based upon an annealing history of the at least one component. As another example, determining when the at least one component is to be annealed at the block 240 may be based upon an operational history of the at least one component. Given by way of non-limiting example, the operational history of the nuclear fission fuel assembly may include temperature history and/or radiation exposure or the like. In some other embodiments and referring now to FIG. 2U, determining when the at least one component is to be annealed at the block 240 may include testing materials that are indicative of the at least one component at a block 244. In some embodiments and referring to FIG. 2V, testing materials that are indicative of the at least one component at the block 244 can include testing at least a portion of the at least one component at a block 246. Given by way of non-limiting example, referring to FIG. 2W testing materials that are indicative of the at least one component at the block 246 may include testing for changes in material properties indicative of radiation damage at a block 248. For example, some illustrative material properties indicative of radiation damage may include electrical resistivity, physical dimensions, displacement response to physical stress, response to stimulus, speed of sound within material, ductile-to-brittle transition temperature, and/or radiation emission. In some embodiments and referring to FIG. 2X, annealing at least the portion of the at least one component within the annealing temperature range is stopped at a block 250. A determination of when to stop annealing at least the portion of the at least one component within the annealing temperature range at the block 250 may be made in any manner as desired for a particular application. For example, in some embodiments annealing may be stopped at the block 250 after a predetermined time period. Given by way of non-limiting example, the predetermined time period may be a function of temperature. In some other embodiments, the predetermined time period may be a function of changes in material properties indicative of radiation damage. In some embodiments the predetermined time period may be a function of radiation exposure. Referring now to FIG. 2Y, in some embodiments material properties of at least a portion of the at least one component may be tested at a block 252 during annealing at the block 206. In such an arrangement, annealing at the block 206 is stopped at a block 250A responsive to testing material properties of at least a portion of the at least one component. After annealing has been stopped at the block 250, it may be desirable in some embodiments to further treat that which has been annealed. To that end and referring now to FIG. 2Z, in some embodiments at a block 256 at least the portion of the at least one component can be treated with post-annealing treatment. In some embodiments, post-annealing treatment can include quenching. To that end and referring to FIG. 2AA, in some embodiments post-anneal treating at least the portion of the at least one component at the block 256 can include lowering temperature from the annealing temperature range to a quenching temperature range at a block 258. Referring to FIG. 2AB, in some embodiments lowering temperature to a quenching temperature range at the block 258 can include lowering temperature at a predetermined rate at a block 260. In some other embodiments, post-anneal treating can also include tempering after quenching. To that end and referring to FIG. 2AC, in some embodiments post-anneal treating at least the portion of the at least one component at the block 256 can also include raising temperature from the quenching temperature range to a tempering temperature range at a block 262. Referring now to FIG. 2AD, in some embodiments after annealing has stopped at the block 250 temperature may be established at an operational temperature range at a block 266, if desired. Referring now to FIG. 2AE, in some embodiments annealing at the block 206 can be performed after commencement of transition of reactivity condition of at least a portion of the nuclear fission reactor from a first state to a second state at a block 254. Given by way of non-limiting example, the first state can include power range operation and the second state can include a shut-down state. It will be appreciated that any number of components and any number of fuel assemblies and their components may be annealed, as desired for a particular application. For example, in some embodiments fewer than all nuclear fission fuel assemblies of a reactor core of the nuclear fission reactor can be annealed. In some other embodiments, substantially all nuclear fission fuel assemblies of a reactor core of the nuclear fission reactor can be annealed, as desired. Referring now to FIG. 3A, the illustrative method 300 for treating at least a portion of at least one component of a reactor core of a nuclear fission reactor begins at a block 302. At a block 304 a temperature of a region of a reactor core of a nuclear fission reactor is elevated, from a predetermined operating temperature range to an annealing temperature range, for a time period sufficient to produce annealing of at least a portion of at least one selected component of the region of the reactor core without removing the at least one selected component from the reactor core. The method 300 stops at a block 306. Illustrative aspects will be described briefly below. While the method 100 (FIG. 1A) discloses annealing at least a portion of at least one metallic component of a nuclear fission fuel assembly of a nuclear fission reactor, the method 300 discloses annealing at least a portion of any component or components of a reactor core of a nuclear fission reactor. Thus, similar to the method 200 (FIG. 2A), the method 300 can be used for annealing at least a portion of one or more reactor core components such as without limitation a nuclear fission fuel assembly, a reactor core cooling component, and/or a reactor core structural member, non-limiting examples of which are discussed above. In some arrangements, the method 300 can be used to anneal at least a portion of one or more components of a nuclear fission fuel assembly, such as without limitation cladding, a cooling component, a structural member, a thermally conductive member, and/or nuclear fission fuel material, non-limiting examples of which are discussed above. Moreover (and also similar to the method 200 (FIG. 2A)), the method 300 can be performed on any component or components of a reactor core—regardless of whether the component is metallic or not. Thus, annealing as disclosed by the method 300 can permit use in reactor cores of advanced materials, such as composite materials like SiC/SiC or the like. However, it will be appreciated that the method 300 may also be used for a one or more reactor core components that are made of metals—such as without limitation steel, oxide dispersion strengthened (ODS) steels, austenitic steels (304, 316), ferritic/martensitic steels refractory metal, a refractory metal alloy, a non-ferrous metal, a non-ferrous metal alloy, and/or a superalloy (such as Inconels, Zircaloys, and/or Hastelloys). Further, while the annealing temperature range for the method 100 (FIG. 1A) need not be higher than an operating temperature range, it will be noted that at the block 304 temperature of a region of a reactor core of a nuclear fission reactor is elevated from a predetermined operating temperature range to an annealing temperature range. Lastly, while annealing performed by either the method 100 (FIG. 1A) or the method 200 (FIG. 2A) need not occur within a reactor core, it will also be noted that the method 300 can produce annealing of at least a portion of at least one selected component of the region of the reactor core without removing the at least one selected component from the reactor core. With the exception of the differences noted directly above, other aspects of the method 300 are similar to aspects of the method 100 (FIG. 1A). To that end and for sake of brevity, aspects of the method 300 will be described briefly. As noted above, at the block 304 temperature of a region of a reactor core of a nuclear fission reactor is elevated from a predetermined operating temperature range to an annealing temperature range. The discussion of optional arrangements of the method 100 (FIG. 1A) in which annealing temperature range is higher than a predetermined operating temperature range is applicable to the method 300. Thus, details of the annealing temperature range being higher than the operating temperature range need not be repeated for an understanding. However, aspects of the method 300 will be noted below for completeness. For example, in some embodiments, the annealing temperature range may be determined based upon any one or more factors such as radiation exposure of the at least one component, an operating temperature history during which the radiation occurred, and/or an annealing history of the component to be annealed. In some other embodiments, the annealing temperature range may be determined based upon material properties of the at least one selected component. For example, in some embodiments a minimum temperature of the annealing temperature range may be at least around thirty percent of a melting point of the at least one selected component. As another example, in some other embodiments, an annealing temperature within the annealing temperature range may be around forty percent of a melting point of the at least one selected component. In some embodiments, a maximum temperature of the annealing temperature range may be selected as desired to provide a predetermined safety margin below a melting point of at least one selected component. In some other embodiments, a maximum temperature of the annealing temperature range may be selected as desired to provide a predetermined safety margin below structural degradation of at least one selected component. Elevating the temperature to perform annealing at the block 304 can be performed in various locations of a reactor core, as desired. For example, in some embodiments elevating the temperature to perform annealing of at least the portion of the at least one selected component can be performed in-place. However, the at least one selected component need not be annealed in-place. For example and referring now to FIG. 3B, in some other embodiments the at least one selected component to be annealed may be moved at a block 310 from an in-place location prior to elevating the temperature to perform annealing at the block 304. It will be noted that, as discussed above, elevating the temperature to perform annealing is performed within a reactor core of the nuclear fission reactor. Thus, in some arrangements, the at least one selected component may be moved from its in-place location to another location within the reactor core where the annealing is to take place. In some embodiments and referring now to FIG. 3C, the at least one selected component may be moved to a location within a reactor core of the nuclear fission reactor after elevating the temperature to perform annealing. In some embodiments and referring to FIG. 3D, at a block 313 the at least one selected component may be re-oriented annealing. In some other embodiments and referring to FIG. 3E, at a block 315 the at least one selected component may be reconfigured. As another example and referring to FIG. 3F, at a block 314 the at least one selected component may be moved from an in-place location after elevating the temperature to perform annealing. Elevating the temperature to perform annealing at the block 304 can be performed in various manners as desired for a particular application. For example and referring to FIG. 3G, in some embodiments elevating the temperature to perform annealing at the block 304 can include adjusting operational parameters of the nuclear fission reactor to establish operating conditions of the region of the nuclear fission reactor containing the at least one selected component within the annealing temperature range for a period of time selected to produce annealing of at least the portion of the at least one metallic component at a block 316. In some embodiments and referring to FIG. 3H, adjusting operational parameters at the block 316 can include raising (that is, changing) temperature of the region of the nuclear fission reactor containing the at least one selected component from a predetermined operating temperature range of the reactor core toward the annealing temperature range at a block 318. Referring to FIG. 3I, adjusting operational parameters at the block 316 can include maintaining temperature of the region of the nuclear fission reactor containing the at least one selected component substantially within the annealing temperature range at a block 320. Illustrative details regarding adjusting operational parameters to raise and/or maintain temperature and regarding selecting a period of time to produce annealing will be discussed below. Referring now to FIG. 3J, adjusting operational parameters at the block 316 can include providing heat from an external heat source at a block 322. In some embodiments, the external heat source can include at least one electrical heat source. In some other embodiments, the external heat source can include at least one source of residual heat. For example, the residual heat can include decay heat. In some other embodiments, the external heat source can include a heating fluid. In some other embodiments and referring to FIG. 3K, adjusting operational parameters at the block 316 can include substantially maintaining coolant flow rate at a block 324 and reducing an amount of heat transferred from the coolant at a block 326. Similarly and referring to FIG. 3L, in some embodiments adjusting operational parameters at the block 316 can include substantially maintaining coolant flow rate at the block 324 and reducing an amount of heat transferred to the coolant at a block 328. In other embodiments, referring to FIG. 3M adjusting operational parameters at the block 316 can include lowering, from a predetermined coolant flow rate, coolant flow rate into the region of the nuclear fission reactor containing the at least one selected component at a block 330. In other embodiments, referring to FIG. 3N adjusting operational parameters at the block 316 can include reversing direction of reactor coolant flow into the region of the nuclear fission reactor containing the at least one selected component at a block 331. In other embodiments, referring to FIG. 3O adjusting operational parameters at the block 316 can include raising temperature of coolant entering the region of the nuclear fission reactor containing the at least one selected component at a block 332. In some embodiments, referring to FIG. 3P adjusting operational parameters at the block 316 can include replacing at least a portion of a first reactor coolant having first heat transfer characteristics with second coolant having second heat transfer characteristics at a block 334. Referring now to FIG. 3Q, in some embodiments adjusting operational parameters at the block 316 can include raising pressure in the region of the nuclear fission reactor containing the at least one selected component at a block 336. Referring now to FIG. 3R, in some other embodiments adjusting operational parameters at the block 316 can include lowering pressure in the region of the nuclear fission reactor containing the at least one selected component. Referring now to FIG. 3S, a determination may be made at a block 340 regarding when the at least one selected component is to be annealed. The determination of when the at least one selected component is to be annealed may be made at the block 340 in a variety of manners, as desired for a particular application. For example, in some embodiments and referring to FIG. 3T, determining when the at least one component is to be annealed at the block 340 can include scheduling a predetermined time for annealing the at least one selected component at a block 342. In some other embodiments, determining when the at least one selected component is to be annealed at the block 340 may be based upon history of the at least one selected component. For example, determining when the at least one selected component is to be annealed at the block 340 may be based upon an annealing history of the at least one selected component. As another example, determining when the at least one selected component is to be annealed at the block 340 may be based upon an operational history of the at least one selected component. Given by way of non-limiting example, the operational history of the nuclear fission fuel assembly may include temperature history and/or radiation exposure or the like. In some other embodiments and referring now to FIG. 3U, determining when the at least one selected component is to be annealed at the block 340 may include testing materials that are indicative of the at least one selected component at a block 344. In some embodiments and referring to FIG. 3V, testing materials that are indicative of the at least one selected component at the block 344 can include testing at least a portion of the at least one selected component at a block 346. Given by way of non-limiting example, referring to FIG. 3W testing materials that are indicative of the at least one selected component at the block 346 may include testing for changes in material properties indicative of radiation damage at a block 348. For example, some illustrative material properties indicative of radiation damage may include electrical resistivity, physical dimensions, displacement response to physical stress, response to stimulus, speed of sound within material, ductile-to-brittle transition temperature, and/or radiation emission. In some embodiments and referring to FIG. 3X, elevating the temperature to perform annealing is stopped at a block 350. A determination of when to stop elevating the temperature to perform annealing at the block 350 may be made in any manner as desired for a particular application. For example, in some embodiments elevating the temperature to perform annealing may be stopped at the block 350 after a predetermined time period. Given by way of non-limiting example, the predetermined time period may be a function of temperature. In some other embodiments, the predetermined time period may be a function of changes in material properties indicative of radiation damage. In some embodiments the predetermined time period may be a function of radiation exposure. Referring now to FIG. 3Y, in some embodiments material properties of at least a portion of the at least one selected component may be tested at a block 352 during elevating the temperature to perform annealing at the block 304. In such an arrangement, elevating the temperature to perform annealing at the block 304 is stopped at a block 350A responsive to testing material properties of at least a portion of the at least one selected component. After annealing has been stopped at the block 350, it may be desirable in some embodiments to further treat that which has been annealed. To that end and referring now to FIG. 3Z, in some embodiments at a block 356 at least the portion of the at least one selected component can be treated with post-annealing treatment. In some embodiments, post-annealing treatment can include quenching. To that end and referring to FIG. 3AA, in some embodiments post-anneal treating at least the portion of the at least one selected component at the block 356 can include lowering temperature from the annealing temperature range to a quenching temperature range at a block 358. Referring to FIG. 3AB, in some embodiments lowering temperature to a quenching temperature range at the block 358 can include lowering temperature at a predetermined rate at a block 360. In some other embodiments, post-annealing treatment can also include tempering after quenching. To that end and referring to FIG. 3AC, in some embodiments post-anneal treating at least the portion of the at least one selected component at the block 356 can also include raising temperature from the quenching temperature range to a tempering temperature range at a block 362. Referring now to FIG. 3AD, in some embodiments after annealing has stopped at the block 350 temperature may be established at an operational temperature range at a block 366, if desired. Referring now to FIG. 3AE, in some embodiments elevating the temperature to perform annealing at the block 304 can be performed after commencement of transition of reactivity condition of at least a portion of the nuclear fission reactor from a first state to a second state at a block 354. Given by way of non-limiting example, the first state can include power range operation and the second state can include a shut-down state. It will be appreciated that any number of components and any number of fuel assemblies and their components may be annealed, as desired for a particular application. For example, in some embodiments fewer than all nuclear fission fuel assemblies of a reactor core of the nuclear fission reactor can be annealed. In some other embodiments, substantially all nuclear fission fuel assemblies of a reactor core of the nuclear fission reactor can be annealed, as desired. Referring now to FIG. 4A, the illustrative method 400 for producing an annealing effect begins at a block 402. At a block 404 a reactor coolant system is adjusted to produce a temperature deviation from a nominal operating temperature range. At a block 406 the temperature deviation from the nominal operating temperature is maintained for a period selected to produce a selected annealing effect. At a block 408, after the period selected to produce the selected annealing effect, the reactor coolant system is adjusted to return to the nominal operating temperature range. The method 400 stops at a block 410. Illustrative details will be set forth below. In some embodiments, the selected annealing effect can anneal at least a portion of at least one reactor core component such as at least one nuclear fission fuel assembly, reactor core cooling component, and/or reactor core structural member. When at least one nuclear fission fuel assembly is annealed, the annealed component can include cladding, a cooling component, a structural member, a thermally conductive member, and/or nuclear fission fuel material. In some embodiments, the selected annealing effect can include a predicted annealing effect. That is, a desired extent of annealing to be performed can be predicted. The desired extent of annealing can be a function of one or more factors, such as annealing temperature, annealing time, material properties of a component to be annealed, exposure of the component to be annealed, operational history of the component to be annealed, and/or annealing history of the component to be annealed, all of which have been discussed above. In some other embodiments the selected annealing effect can include a measured annealing effect. That is, as discussed above material properties of the component can be monitored as desired during annealing. When the monitored material properties return to a desired range of values, the selected annealing effect has been produced, and the reactor coolant system can be adjusted to return to the nominal operating temperature range at the block 410. Referring to FIG. 4B, in some embodiments adjusting a reactor coolant system to produce a temperature deviation from a nominal operating temperature range at the block 404 can include adjusting reactor coolant flow at a block 412. As discussed above, reactor coolant flow can be adjusted by throttling a flow adjustment device, such as a valve. As another example, reactor coolant flow can be adjusted by shifting reactor coolant pump speed, such as between fast speed and slow speed, or by changing the number of operating reactor coolant pumps. In other embodiments, referring to FIG. 4C direction of reactor coolant flow at a block 413. Referring now to FIG. 4D and in some embodiments, in addition to adjusting a reactor coolant system to produce a temperature deviation from a nominal operating temperature range at the block 404, a rate of heat generation can be adjusted at a block 414. Given by way of non-limiting examples and as discussed above, heat generation can be adjusted by providing heat from an external heat source, such as at least one electrical heat source, a heating fluid, and/or at least one source of residual heat, such as decay heat. In addition, heat generation may be adjusted temporarily by adjusting reactivity, such as without limitation by withdrawing or inserting control rods or otherwise adjusting an amount of neutron absorbing material, thereby raising or lowering reactor coolant temperature. It will be appreciated that such an adjustment of heat generation may have a temporary effect on temperature in nuclear fission reactors with a negative temperature coefficient of reactivity αT. Referring to FIG. 4E, in some embodiments adjusting a reactor coolant system to produce a temperature deviation from a nominal operating temperature range at the block 404 can include adjusting a rate of heat transferred from the reactor coolant at a block 416. As discussed above, a rate of heat transferred from the reactor coolant can be adjusted in a number of ways. Given by way of non-limiting examples, an amount of fluid that exits a secondary side of a heat exchanger through which reactor coolant flows on a primary side can be adjusted; a valve can be throttled toward a shut position on a secondary side of a primary-to-secondary heat exchanger in a pressurized water reactor, a pool-type liquid metal fast breeder reactor, or a gas-cooled fast breeder reactor; a valve can be throttled toward a shut position on an intermediate side of an intermediate heat exchanger in a loop-type liquid metal fast breeder reactor; a heat load presented to any of the heat exchangers described above can be reduced; or the like. Referring to FIG. 4F, in some other embodiments adjusting a reactor coolant system to produce a temperature deviation from a nominal operating temperature range at the block 404 can include adjusting a rate of heat transferred to the reactor coolant at a block 418. As discussed above, a rate of heat transferred to the reactor coolant can be adjusted in a number of ways. Given by way of non-limiting examples, the heat transfer that is adjusted is the heat transfer from a fuel assembly containing the component to be annealed to the reactor coolant. Given by way of non-limiting examples, an amount of heat transferred to the coolant can be adjusted by adjusting an amount of fluid that exits a secondary side of a heat exchanger through which reactor coolant flows on a primary side. For example, a valve can be throttled on a secondary side of a primary-to-secondary heat exchanger in a pressurized water reactor, a pool-type liquid metal fast breeder reactor, or a gas-cooled fast breeder reactor. As a further example, a valve can be throttled on an intermediate side of an intermediate heat exchanger in a loop-type liquid metal fast breeder reactor. Given by way of further example, a heat load presented to any of the heat exchangers described above can be adjusted. Referring now to FIG. 4G, in some embodiments adjusting a reactor coolant system to produce a temperature deviation from a nominal operating temperature range at the block 404 can include replacing at least a portion of a first reactor coolant having first heat transfer characteristics with second coolant having second heat transfer characteristics at a block 420. Examples of replacement of at least a portion of reactor coolant have been discussed above. Referring to FIG. 4H, in some embodiments adjusting a reactor coolant system to produce a temperature deviation from a nominal operating temperature range at the block 404 can include adjusting temperature of reactor coolant at a block 422. Given by way of non-limiting examples, temperature of reactor coolant can be adjusted by adding pump heat, such as by increasing the number of operating reactor coolant pumps or by increasing the pump velocity for a given level of heat rejection from either the primary or intermediate cooling loops. It will be appreciated that, when the reactor is shut down, addition of pump heat can raise reactor coolant temperature. For a reactor coolant pump, pump power is proportional to velocity. Moreover, for a typical reactor coolant pump, around 1 MW or so of power is typically lost to inefficiency. This lost power is transferred as heat to reactor coolant in the reactor coolant loop. Referring now to FIG. 5A, the illustrative method 500 for annealing at least a portion of at least one component of a nuclear fission reactor core begins at a block 502. At a block 504 a nuclear fission reactor core is operated within a predetermined operating temperature range. At a block 506 the nuclear fission reactor core is shut down. At a block 508 temperature of at least a portion of the nuclear fission reactor core is raised above the predetermined operating temperature range to an annealing temperature range for at least one component of the nuclear fission reactor core. At a block 510 temperature of at least the portion of the nuclear fission reactor core is maintained within the annealing temperature range for a time period selected to perform annealing of at least a portion of the at least one component of the nuclear fission reactor core. The method 500 stops at a block 512. Illustrative details will be set forth below. After temperature of at least the portion of the nuclear fission reactor core was maintained within the annealing temperature range for the time period at the block 510, it may be desirable in some embodiments to further treat at least a part of that which has been annealed. To that end and referring now to FIG. 5B, in some embodiments at a block 556 at least the portion of the at least one component can be treated with post-annealing treatment. In some embodiments, post-annealing treatment can include quenching. To that end and referring to FIG. 5C, in some embodiments post-anneal treating at least the portion of the at least one component at the block 556 can include lowering temperature from the annealing temperature range to a quenching temperature range at a block 558. Referring to FIG. 5D, in some embodiments lowering temperature to a quenching temperature range at the block 558 can include lowering temperature at a predetermined rate at a block 560. In some other embodiments, post-annealing treatment can also include tempering after quenching. To that end and referring to FIG. 5E, in some embodiments post-anneal treating at least the portion of the at least one component at the block 556 can also include raising temperature from the quenching temperature range to a tempering temperature range at a block 562. Referring to FIG. 5F, in some embodiments, at a block 514 temperature of at least the portion of the nuclear fission reactor core can be lowered from the annealing temperature range toward the predetermined operating temperature range after temperature of at least the portion of the nuclear fission reactor core was maintained within the annealing temperature range for the time period. Referring now to FIG. 5G, after temperature of at least the portion of the nuclear fission reactor core has been lowered from the annealing temperature range at the block 514, the nuclear fission reactor core can be re-started at a block 516, as desired. It will be appreciated that applicable initial conditions for re-starting the reactor core should be met when re-starting the reactor core at the block 516. Referring now to FIG. 5H, substantially constant reactor coolant flow can be maintained through at least a portion of the nuclear fission reactor core at a block 518. It will be appreciated that reactor coolant flow can be adjusted as desired, if at all, during operation at the block 504 and shut down at the block 506. Thus, in some embodiments the reactor coolant flow may be maintained substantially constant while raising the temperature at the block 508 and maintaining temperature at the block 510. Referring to FIG. 5I, in some embodiments raising temperature of at least a portion of the nuclear fission reactor core above the predetermined operating temperature range to an annealing temperature range at the block 508 can include adding heat to fluid in thermal communication with at least a portion of the nuclear fission reactor core at a block 520. As discussed above, heat can be added by providing heat from an external heat source, such as at least one electrical heat source or a heating fluid. In addition, pump heat may be added to reactor coolant by operating reactor coolant pumps. Referring to FIG. 5J, in some embodiments raising temperature of at least a portion of the nuclear fission reactor core above the predetermined operating temperature range to an annealing temperature range at the block 508 can include generating decay heat at a block 522. Generation of decay heat has been discussed above. Referring now to FIG. 5K, in some embodiments raising temperature of at least a portion of the nuclear fission reactor core above the predetermined operating temperature range to an annealing temperature range at the block 508 can include reducing an amount of heat transferred to reactor coolant at a block 524. As discussed above, in some embodiments the heat transfer that can reduced is the heat transfer, such as decay heat, from a fuel assembly containing the component to be annealed to the reactor coolant. Given by way of non-limiting example, an amount of heat transferred to the coolant can be reduced by reducing an amount of fluid that exits a secondary side of a heat exchanger through which reactor coolant flows on a primary side. For example, a valve can be throttled toward a shut position on a secondary side of a primary-to-secondary heat exchanger in a pressurized water reactor, a pool-type liquid metal fast breeder reactor, or a gas-cooled fast breeder reactor. As a further example, a valve can be throttled toward a shut position on an intermediate side of an intermediate heat exchanger in a loop-type liquid metal fast breeder reactor. Given by way of further example, a heat load presented to any of the heat exchangers described above can be reduced. Referring to FIG. 5L, in some other embodiments raising temperature of at least a portion of the nuclear fission reactor core above the predetermined operating temperature range to an annealing temperature range at the block 508 can include reducing an amount of heat transferred from reactor coolant at a block 526. As discussed above, in some embodiments the heat transfer that is reduced is the heat transfer from the reactor coolant to a heat exchanger. Given by way of non-limiting example, an amount of heat transferred from the coolant can be reduced by reducing an amount of fluid that exits a secondary side of a heat exchanger through which reactor coolant flows on a primary side. For example, a valve can be throttled toward a shut position on a secondary side of a primary-to-secondary heat exchanger in a pressurized water reactor, a pool-type liquid metal fast breeder reactor, or a gas-cooled fast breeder reactor. As a further example, a valve can be throttled toward a shut position on an intermediate side of an intermediate heat exchanger in a loop-type liquid metal fast breeder reactor. Given by way of further example, a heat load presented to any of the heat exchangers described above can be reduced. Referring now to FIG. 5M, in some embodiments reducing an amount of heat transferred from reactor coolant at the block 526 can include maintaining reactor coolant flow rate substantially constant at a block 528. However, in some other embodiments and referring to FIG. 5N, reducing an amount of heat transferred from reactor coolant at the block 526 can include reducing reactor coolant flow rate at a block 530. Reducing reactor coolant flow rate has been discussed above. Referring to FIG. 5O, in some other embodiments reducing an amount of heat transferred from reactor coolant at the block 526 can include substantially stopping transfer of heat from reactor coolant at a block 532. Given by way of non-limiting example, heat transfer from the reactor coolant may be substantially stopped, if desired, by performing any one or more of the techniques discussed above for the block 526 in conjunction with reducing reactor coolant flow rate, as desired for a particular application. Referring to FIG. 5P, in some embodiments raising temperature of at least a portion of the nuclear fission reactor core above the predetermined operating temperature range to an annealing temperature range at the block 508 can include raising temperature of reactor coolant entering at least the portion of the nuclear fission reactor core at a block 534. Given by way of non-limiting example, temperature of reactor coolant can be raised by providing heat from an external heat source, such as at least one electrical heat source or a heating fluid. In addition, pump heat may be added to reactor coolant by operating reactor coolant pumps. Moreover, decay heat may also raise temperature of reactor coolant. Referring to FIG. 5Q, maintaining temperature of at least the portion of the nuclear fission reactor core within the annealing temperature range for a time period at the block 510 can include establishing substantially isothermal conditions within at least the portion of the nuclear fission reactor core within the annealing temperature range at a block 536. For example and referring now to FIG. 5R, in some embodiments establishing substantially isothermal conditions within at least the portion of the nuclear fission reactor core within the annealing temperature range at the block 536 can include transferring a reduced amount of heat by reactor coolant that is less than a predetermined amount of heat transferred by reactor coolant during reactor operation at a block 538. Referring now to FIG. 5S, in some embodiments reducing an amount of heat transferred to reactor coolant at the block 524 can include replacing at least a portion of a first reactor coolant having first heat transfer characteristics with second coolant having second heat transfer characteristics at a block 540. Replacing a portion of reactor coolant has been discussed above. Referring to FIG. 5T, in some embodiments raising temperature of at least a portion of the nuclear fission reactor core above the predetermined operating temperature range to an annealing temperature range for at least one component of the nuclear fission reactor core at the block 508 can include raising pressure in at least the portion of the nuclear fission reactor core at a block 542. Raising pressure has been discussed above. It will be appreciated that any portion of the reactor core may be annealed, as desired for a particular application. For example, in some embodiments less than all of the reactor core can be annealed. In some other embodiments, substantially all of the reactor core of the nuclear fission reactor can be annealed, as desired. Illustrative Systems and Apparatuses Illustrative systems and apparatuses will now be described. The illustrative systems and apparatuses can provide host environments for performance of any of the methods described herein. It will be appreciated that the illustrative systems and apparatuses shown in the accompanying FIGS. 8A-8K and described below are illustrated in functional block diagram form. As such, the block diagrams of FIGS. 8A-8K show illustrative functions and are not intended to convey limitations on locations of all components that may perform the illustrated functions. In addition, any type of nuclear fission reactor whatsoever may serve as a host environment for the systems and apparatuses shown in FIGS. 8A-8K. Referring to FIG. 8A, a functional relationship is illustrated in which at least a portion of at least one component 810 may be annealed by heat transfer, indicated by an arrow 812, from a heat source 814 that is in thermal communication (as indicated by the arrow 812) with at least the portion of the component 810. In the relationship shown in FIG. 8A, annealing can occur within a reactor pressure vessel 816. The component 810 may include any of the components discussed above. In some embodiments and given by way of non-limiting example, the component 810 can include at least one reactor core component such as at least one nuclear fission fuel assembly, reactor core cooling component, and/or reactor core structural member. When at least one nuclear fission fuel assembly is annealed, the component 810 can include cladding, a cooling component, a structural member, a thermally conductive member, and/or nuclear fission fuel material. The heat source 814 may include any of the heat sources discussed above. In some embodiments in which the heat source 814 is located within the reactor pressure vessel 816, the heart source 814 may include nuclear fission fuel material, such as that contained in nuclear fission fuel elements and/or fuel assemblies, thereby generating heat during power range operations or by generating decay heat after shutdown from power range operations. In some other embodiments, the heat source 814 may include an external heat source (that is, external to a fuel assembly), such as at least one electrical heat source, a heating fluid, and/or at least one source of residual heat, such as decay heat. As shown in FIG. 8A, the heat transfer mechanism of thermal communication between the heat source 814 and the component 810 can include reactor coolant. The reactor coolant can include liquid metal or gaseous reactor coolant, non-limiting examples of which have been described above. Referring to FIG. 8B, in some embodiments the component 810 and the heat source 814 are located in a reactor core assembly 818 within the reactor pressure vessel 816. In such an arrangement, and as indicated by the arrow 812, annealing of at least the portion of the component 810 can occur within the reactor core assembly 818. In some embodiments, annealing of at least the portion of the component 810 can be performed in an in-place location of the component 810. In some other embodiments, the component 810 can be moved, with suitable handling equipment, from its in-place location to another location within the reactor core assembly 818 where annealing can occur. Referring to FIG. 8C, in some embodiments the component 810 can be re-located from the reactor core assembly 818 with suitable handling equipment. In such an arrangement, and as indicated by the arrow 812, annealing of at least the portion of the component 810 can occur exterior of the reactor core assembly 818 but within the reactor pressure vessel 816. Referring to FIG. 8D, in some other embodiments the component 810 can be re-located, as indicated by an arrow 820, from the reactor pressure vessel 816 with suitable handling equipment and placed within suitable nuclear shielding 822 in an annealing facility, as desired. In such an arrangement, and as indicated by the arrow 812, annealing of at least the portion of the component 810 can occur exterior of the reactor pressure vessel 816. Also, in such an arrangement, the heat source 814 can be any of the heat sources described above. However, when the heat source 814 includes nuclear fission fuel material (such as when a nuclear fission fuel element or a fuel assembly is removed from the reactor pressure vessel 816 and relocated to the nuclear shielding 822 within the annealing facility) then the heat is generated via decay heat generation as opposed to power range operations. In some embodiments, annealing can occur on-site of the nuclear fission reactor. In some other embodiments, annealing can occur off-site from the nuclear fission reactor. Referring to FIG. 8E, in some embodiments heat transfer from the heat source 814 to the component 810 can be adjusted, such as with a flow adjust function 824. The flow adjust function 824 can cause reactor coolant flow to be adjusted, thereby adjusting amount of heat transferred from the heat source 814 to the component 810. In some embodiments the flow adjust function can be responsive to a control input 826. In some embodiments the control input 826 can be a mechanical input. In some other embodiments the control input 826 can be a signal input, such as an electrical signal, an optical signal, a radio-frequency signal, or the like. In some embodiments systems and apparatuses are provided for annealing at least a portion of at least one component. Referring to FIG. 8F, in some embodiments an illustrative apparatus 830 includes electrical circuitry 832, such as a control system, configured to determine an annealing temperature range for at least a portion of at least one component 810 of a nuclear fission fuel assembly of a nuclear fission reactor. A subassembly 834 is responsive to the electrical circuitry 832 and is configured to establish at least the portion of the nuclear fission fuel assembly within the annealing temperature range. In some other embodiments, the electrical circuitry 832 may be configured to determine an annealing temperature range for at least the portion of at least one component 810 of the reactor core assembly 818 of a nuclear fission reactor, wherein the annealing temperature range is higher than a predetermined operating temperature range of the reactor core assembly 818. In such an arrangement, the subassembly 834 is responsive to the electrical circuitry 832 and is configured to establish at least the portion of the nuclear fission reactor within the annealing temperature range. It will be appreciated that in some embodiments the electrical circuitry 832 may include a numerical model of material damage and/or annealing/temperature response. In some other embodiments the electrical circuitry 832 may include stored data representing annealing/temperature responses discussed above. The stored data may be determined empirically or analytically, as desired, and may be updated or supplemented with sensor data (e.g. acoustic response of steel showing degradation or restoration, or the like). In a general sense, those skilled in the art will recognize that the various aspects described herein which can be implemented, individually and/or collectively, by a wide range of hardware, software, firmware, or any combination thereof can be viewed as being composed of various types of “electrical circuitry.” Consequently, as used herein “electrical circuitry” includes, but is not limited to, electrical circuitry having at least one discrete electrical circuit, electrical circuitry having at least one integrated circuit, electrical circuitry having at least one application specific integrated circuit, electrical circuitry forming a general purpose computing device configured by a computer program (e.g., a general purpose computer configured by a computer program which at least partially carries out processes and/or devices described herein, or a microprocessor configured by a computer program which at least partially carries out processes and/or devices described herein), electrical circuitry forming a memory device (e.g., forms of random access memory), and/or electrical circuitry forming a communications device (e.g., a modem, communications switch, or optical-electrical equipment). Those having skill in the art will recognize that the subject matter described herein may be implemented in an analog or digital fashion or some combination thereof. In a general sense, those skilled in the art will also recognize that in the various embodiments described herein the subassembly 834 can be implemented, individually and/or collectively, by various types of electro-mechanical systems having a wide range of electrical components such as hardware, software, firmware, or virtually any combination thereof; and a wide range of components that may impart mechanical force or motion such as rigid bodies, spring or torsional bodies, hydraulics, and electro-magnetically actuated devices, or virtually any combination thereof. Consequently, as used herein “electro-mechanical system” includes, but is not limited to, electrical circuitry operably coupled with a transducer (e.g., an actuator, a motor, a piezoelectric crystal, etc.), electrical circuitry having at least one discrete electrical circuit, electrical circuitry having at least one integrated circuit, electrical circuitry having at least one application specific integrated circuit, electrical circuitry forming a general purpose computing device configured by a computer program (e.g., a general purpose computer configured by a computer program which at least partially carries out processes and/or devices described herein, or a microprocessor configured by a computer program which at least partially carries out processes and/or devices described herein), electrical circuitry forming a memory device (e.g., forms of random access memory), electrical circuitry forming a communications device (e.g., a modem, communications switch, or optical-electrical equipment), and any non-electrical analog thereto, such as optical or other analogs. Those skilled in the art will also appreciate that examples of electro-mechanical systems include but are not limited to a variety of consumer electronics systems, as well as other systems such as motorized transport systems, factory automation systems, security systems, and communication/computing systems. Those skilled in the art will recognize that electro-mechanical as used herein is not necessarily limited to a system that has both electrical and mechanical actuation except as context may dictate otherwise. The apparatus 830 may include a sensing system 836 that provides sensed data to the electrical circuitry 832. In some embodiments the sensing system 836 may be configured to sense conditions, such as temperature, pressure, reactor coolant flow rate, or the like, of the region of the reactor core assembly 818 containing the component 810. As such, the sensing system 836 may include sensors such as temperature sensors, pressure sensors, flow sensors, or the like. In some other embodiments the sensing system 836 may be further configured to test material properties of at least a portion of the component 810 during annealing. As discussed above, in some embodiments the heat source 814 can include an external heat source, such as at least one electrical heat source and/or a heating fluid, and/or at least one source of residual heat, such as decay heat. In some embodiments the subassembly 834 can be further configured to adjust operational parameters of the nuclear fission reactor to establish operating conditions of a region of the nuclear fission reactor containing the at least one component within the determined annealing temperature range for a period of time selected to produce annealing of at least the portion of the at least one component. Referring now to FIG. 8G, in some embodiments the subassembly 834 can include a reactor coolant system. Given by way of non-limiting example and referring to FIG. 8H, the reactor coolant system can include at least one reactor coolant pump 838. In some embodiments the at least one reactor coolant pump 838 can be responsive to a reactor coolant pump controller 840, such as for starting, stopping, and/or changing speeds of the reactor coolant pump 838. In some other embodiments and referring to FIG. 8I, the reactor coolant system can include at least one flow adjustment device 842, such as a valve like an isolation valve, a throttle valve, or the like. The flow adjustment device 842 can be a mechanical device with mechanical actuation, a mechanical device with electrical actuation, or an electrical device that can electrically control flow of electrically-conductive liquid reactor coolant, such as liquid metals. In some embodiments the at least one flow adjustment device 842 can be responsive to a flow adjustment device controller 844. Referring now to FIG. 8J, in some other embodiments the subassembly 834 can include a reactor control system. Given by way of non-limiting example, the reactor control system can control reactivity within the reactor core assembly 818, such as by inserting or withdrawing control rods or otherwise inserting or removing neutron absorbing material or the like. Referring to FIG. 8K, in some embodiments the subassembly 834 can include a pressurizer. Given by way of non-limiting example, the pressurizer can control pressure by turning on or turning off pressurizer heaters, as desired. One skilled in the art will recognize that the herein described components (e.g., blocks), devices, and objects and the discussion accompanying them are used as examples for the sake of conceptual clarity and that various configuration modifications are within the skill of those in the art. Consequently, as used herein, the specific exemplars set forth and the accompanying discussion are intended to be representative of their more general classes. In general, use of any specific exemplar herein is also intended to be representative of its class, and the non-inclusion of such specific components (e.g., blocks), devices, and objects herein should not be taken as indicating that limitation is desired. With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations are not expressly set forth herein for sake of clarity. While particular aspects of the present subject matter described herein have been shown and described, it will be apparent to those skilled in the art that, based upon the teachings herein, changes and modifications may be made without departing from the subject matter described herein and its broader aspects and, therefore, the appended claims are to encompass within their scope all such changes and modifications as are within the true spirit and scope of the subject matter described herein. Furthermore, it is to be understood that the invention is defined by the appended claims. It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as “open” terms (e.g., the term “including” should be interpreted as “including but not limited to,” the term “having” should be interpreted as “having at least,” the term “includes” should be interpreted as “includes but is not limited to,” etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases “at least one” and “one or more” to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles “a” or “an” limits any particular claim containing such introduced claim recitation to inventions containing only one such recitation, even when the same claim includes the introductory phrases “one or more” or “at least one” and indefinite articles such as “a” or “an” (e.g., “a” and/or “an” should typically be interpreted to mean “at least one” or “one or more”); the same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should typically be interpreted to mean at least the recited number (e.g., the bare recitation of “two recitations,” without other modifiers, typically means at least two recitations, or two or more recitations). Furthermore, in those instances where a convention analogous to “at least one of A, B, and C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, and C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to “at least one of A, B, or C, etc.” is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., “a system having at least one of A, B, or C” would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase “A or B” will be understood to include the possibilities of “A” or “B” or “A and B.” With respect to the appended claims, those skilled in the art will appreciate that recited operations therein may generally be performed in any order. Examples of such alternate orderings may include overlapping, interleaved, interrupted, reordered, incremental, preparatory, supplemental, simultaneous, reverse, or other variant orderings, unless context dictates otherwise. With respect to context, even terms like “responsive to,” “related to,” or other past-tense adjectives are generally not intended to exclude such variants, unless context dictates otherwise. While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.
	summary
	claims	1. A forged upper shroud section for a shroud of a boiling water nuclear reactor, the shroud comprising at least one cylindrical section, said upper shroud section comprising: a cylindrical shell; a circular shaped flange at one end of said shell, said flange and said cylindrical shell machined from one forging as one piece; at least one of a plurality of openings and a plurality of slots in said flange; and a circumferential groove machined into and extending substantially completely around an inside surface of said cylindrical shell. 2. A forged upper shroud section in accordance with claim 1 wherein said cylindrical shell comprises an end configured to be welded to a cylindrical section of the shroud. claim 1 3. A forged upper shroud section in accordance with claim 1 wherein a thickness of said flange is selected to carry loads from a shroud head. claim 1 4. A forged upper shroud section in accordance with claim 1 further comprising a gusset extending between said flange and cylindrical shell. claim 1 5. A forged upper shroud section in accordance with claim 1 wherein a thickness of said cylindrical shell is selected to carry loads from a shroud head and radial loads from a top guide grid. claim 1 6. A shroud for a boiling water nuclear reactor, said shroud comprising: at least one cylindrical section; a forged upper shroud section comprising a cylindrical shell and a circular shaped flange at a first end of said shell, said flange and said cylindrical shell machined from one forging as one piece, a second end of said cylindrical shell welded to one of said at least one cylindrical section; at least one of a plurality of openings and a plurality of slots in said flange; and a circumferential groove machined into and extending substantially completely around an inside surface of said cylindrical shell. 7. A shroud in accordance with claim 6 wherein a thickness of said flange is selected to carry loads from a shroud head. claim 6 8. A shroud in accordance with claim 6 further comprising a gusset extending between said flange and cylindrical shell. claim 6 9. A shroud in accordance with claim 6 wherein a thickness of said cylindrical shell is selected to carry loads from a shroud head and radial loads from a top guide grid. claim 6 10. A method for fabricating an upper shroud section for a shroud of a boiling water nuclear reactor, the shroud comprising at least one cylindrical section, said method comprising the steps of: machining a flange in a single piece rectangular cross-section ring forging; machining a cylindrical shell in the forging; machining at least one of a plurality of openings and a plurality of slots in the flange; and machining a circumferential groove into and extending substantially completely around an inside surface of the cylindrical shell. 11. A method in accordance with claim 10 further comprising the step of preparing an end of the cylindrical shell to be welded to a cylindrical section of the shroud. claim 10 12. A method in accordance with claim 10 further comprising the step of selecting a thickness of the flange to carry loads from a shroud head. claim 10 13. A method in accordance with claim 10 further comprising the step of machining a gusset extending between the flange and the cylindrical shell. claim 10 14. A method in accordance with claim 10 further comprising the step of selecting a thickness of the cylindrical shell to carry loads from a shroud head and radial loads from a top guide grid. claim 10
056617666	description	DETAILED DESCRIPTION The system of the present invention measures the bow and twist of either an unirradiated nuclear fuel assembly, or an irradiated nuclear fuel assembly which has been removed from the reactor core. This is done by using a non-contact measuring device in the form of an ultrasonic transponder and a reference measure from which the measurements are made in conjunction with a fixture which constrains the fuel assembly as if the fuel assembly was in the reactor core. By simulating the fuel assembly's actual position within the core, the effect of loading conditions which may not otherwise be present upon bow and twist in the fuel assembly can be measured. Referring to FIG. 1, the system of the present invention is shown. An irradiated fuel assembly 1 shown in schematic form is positioned under water within the fuel assembly bow and twist measuring apparatus 5 in accordance with the present invention. The details of the fuel assembly have been omitted from FIG. 1 for clarity of illustration. Although the present invention is shown and described with reference to an irradiated fuel assembly, an unirradiated or new fuel assembly may similarly be measured by the present invention. The fuel assembly bow and twist measuring system comprises a fixturing apparatus, a reference device, and an ultrasonic measurement device as more fully discussed below. The fuel assembly bow and twist measuring system is positioned underwater to provide protection from the radiation emitted from the irradiated fuel assembly. The fixturing apparatus includes a large diameter tube 10 which encloses the entire length of fuel assembly 1. Tube 10 is secured at its lower end to bottom reference plate 18 and both are secured by flanges 24 which extend downward and rest on a support surface which is depicted in FIG. 1 as the floor of a nuclear fuel assembly spent fuel pool 8 of a typical nuclear power plant (not shown). At the upper end of tube 10 is a top flange 16 which extends around the inner wall of tube 10. Also at the upper end of tube 10 is a removable top 22 which when removed, enables the placement of the fuel assembly within the fuel assembly bow twist measuring apparatus. Bottom reference plate 18 has locating holes 14 which receive the lower alignment pins 2 of fuel assembly 1. Extending from the underside of top 22 are locating pins 12 which engage alignment holes 3 in the top of fuel assembly 1. Each locating pin 12 has a longitudinal axis 12a which defines the longitudinal axis of the fixture. Each locating hole 14 similarly has a longitudinal axis 14a which also defines the longitudinal axis of the fixture. Depending upon the design of the fuel assembly, the longitudinal axis of the fixture can be either the longitudinal axis of a locating pin or the longitudinal axis of a locating hole. In some fuel assembly designs, the fuel assembly lower alignment pins and upper alignment holes are positioned to be collinear in which case the longitudinal axis of the locating pin and the longitudinal axis of the locating hole are also collinear. Locating pins 12 and locating holes 14 are positioned and oriented so as to position the fuel assembly upper tie plate 4a and lower tie plate 4b in relationship to each other as would be found when the fuel assembly is positioned in the reactofuel assembly fuel assembly 1 is placed in the fuel assembly bow twist measuring apparatus 5, fuel assembly position in the reactor core during operating conditions is thereby simulated. Although the configuration of locating pins 12 and locating holes 14 are dependent upon the particular fuel assembly design, the number and position of locating pins and holes in top 22 and bottom plate 18 can be changed to accommodate virtually any fuel assembly type and shape. Thus, while fuel assemblies for boiling water reactors generally do not have lower alignment pins and upper alignment holes, they can nonetheless be tested and measured in the apparatus of the present invention. The reference device includes small diameter reference wires 40(a, b, c, d, e, f, g, and h) which extend from top flange 16 through apertures 19 in bottom reference plate 18 and is secured at its lower end to floating plate 42. Apertures 19 are so positioned in bottom reference plate so that reference wires 40 are each parallel to the longitudinal axis 14a of locating holes 14, as well as the longitudinal axis 12a of locating pins 12 when the removable top is placed in position on the upper flange. Since the longitudinal axis of either the locating pin 12a or the locating hole 14a determines the longitudinal axis of the fixture, the reference wires are parallel to the longitudinal axis of the fixture. The weight of floating plate 42 provides constant tension in reference wires 40. The position of reference wires 40 provide a known relationship between the fuel assembly and the fixture. The number and position of reference wires 40 can be changed (together with the position and orientation of locating pins 12 and locating holes 14) to accommodate different fuel assembly designs. Extending longitudinally through tube 10 are slots 20 which provide openings for the measurement system. The slots 20 are positioned in tube 10 so as to provide a line of sight access to the reference wire 40 which is orthogonal to the fuel assembly 1 as shown in FIG. 2 and more particularly in FIG. 3. The measuring system comprises a transponder 60, a transponder holding block 62, cable 61 which connects transponder 60 to an ultrasonic flaw detector 65 which makes time of flight measurements of ultrasonic signals from transponder 60. As shown in FIG. 3, transponder 60 is positioned in a slot 20 so that it, a reference wire 40, and the specific region or detail of the fuel assembly (e.g. a fuel rod or a guide bar) are in a line of sight which is orthogonal to the detail of the fuel assembly to be measured. After being positioned in one of slots 20 and aimed toward the reference wire 40 and fuel assembly 1, transponder 60 in holding block 62 produces an ultrasonic signal which propagates through the water towards the fuel assembly. A portion of the ultrasonic wave is first reflected from reference wire 40 back to transponder 60 and the remaining wave which occurs later in time, is reflected from the fuel assembly detail back to transponder 60. These signals are then transmitted via cable 61 to ultrasonic flaw detector 65. The time differential between the two signals which is a measure of the distance from the reference wire to the fuel assembly is converted by ultrasonic flaw detector 65 by multiplying the time difference by the velocity of the sound wave through the propagating medium, which for irradiated fuel rods is water. This provides an accurate distance measurement from the reference wire 40 to the detail of the fuel assembly 1. Since the time of flight measurement is performed only from the reference wire to the fuel assembly feature, any error in determining the distance from the ultrasonic transponder to the reference wire is avoided. Thus, accurate positioning of the measuring device relative to a reference position as is attempted in the prior art devices, is not required by the present invention. Transponder 60 is moved from its initial position in a slot 20 to successive positions along the length of the slot where additional ultrasonic signals are produced, and reflected waves from the reference wire and the fuel assembly are received to yield distance measurements from the reference wire to the detail of the fuel assembly as a function of the height of the fuel assembly. The transponder 60 would then be moved to each of the other slots and measurements would again be taken along the height of the fuel assembly or at selected elevations. After placing the nuclear fuel assembly bow and twist measurement apparatus (with the exception of the ultrasonic flow detector 65) on a support surface such as the spent fuel pool floor 8, the apparatus is operated by removing top 22 and placing fuel assembly 1 guided by guides 28 into tube 10, and positioning the fuel assembly lower locating pins 2 in lower locating holes 14 in bottom plate 18. Top 22 would be installed onto top flange 16 and locating pins 12 would be inserted into the fuel assembly upper tie plate holes 3 to secure and position the assembly as if actually positioned within the reactor core. The ultrasonic transponder would be positioned in a slot and measurements taken. The signals received by the transponder from the reference wire and the fuel assembly are transmitted to the ultrasonic flaw detector positioned outside of the spent fuel pool where distance readings would be recorded manually or by a computer. The transponder would be moved in the slot or if desired in any of the other slots and measurements taken at selected locations along the height of the assembly. After all desired measurements were obtained, the top would be removed, and the assembly extracted. Data indicating variations in the distance from the reference wires to the fuel assembly details are a direct measure of bow. For measuring single axis assembly bow, distance variations from adjacent reference wires (e.g. 40a and 40b) on the same side of the fuel assembly will show equal displacement, e.g. x+.DELTA.x where x is the distance from the reference wire to the upper lower tie plate of the fuel assembly, while the corresponding readings from the reference wires on opposite side of the assembly (e.g. 40e and 40f) will show the same magnitude displacement but in the opposite displacement direction, e.g. x-.DELTA.x. (See FIG. 4A) Readings from the adjacent sides of the assembly will show no displacement readings when there is single axis assembly bow. Two axis bow is determined similarly with the exception that all four sides will show displacement magnitude and direction. For determining assembly twist, adjacent readings on the same side of the fuel assembly will show an opposite direction displacement. (See FIG. 4B). The displacement magnitude is a measure of the magnitude of the assembly twist. Comparison of corresponding reference data from the opposite side of the assembly will produce the same displacement magnitude but in opposite direction. An assembly with both bow and twist can be measured by a comparison of the differences in displacement magnitudes and directions from both corresponding opposite and adjacent reference measurements. One of the advantages of the present invention over the prior art is that bow and twist measurements of the fuel assembly positioned and constrained as if it was in the reactor core can be obtained. In addition, since the time of flight measurement is performed only from the reference wire to the fuel assembly feature, the distance from the ultrasonic transponder to the reference wire is irrelevant. Thus, precise positioning me the measuring device relative to a reference position as in the prior art devices, is not required by the present invention. Therefore, an additional advantage of the preset invention is that the precise positioning of the measuring device is not required thereby eliminating inaccuracies and/or the need to provide additional devices intended to correct for the improper positioning of the measuring device. A further advantage of the present invention is the use of ultrasonics for distance measurements which insures greater accuracy (.+-.0.10 inch) due to the elimination of the interaction between the measuring system and the fuel assembly. While the foregoing description and drawings represent the preferred embodiments of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made therein without departing from the true spirit and scope of the present invention.
	claims	1. A flame-retardant and electromagnetic wave-shielding thermoplastic resin composition, comprising:100 parts by weight of a thermoplastic resin (A);from 0.5 to 30 parts by weight of a flame retardant of a halogen-free phosphate (B) represented by the following general formula (1):wherein R1, R2, R3, and R1 each independently represent a hydrogen atom or a monovalent organic group, at least one of R1, R2, R3, and R4 is a monovalent organic group, X is a bivalent organic group, k, l, m, and n are each independently 0 or 1, and N is an integer of 0 to 10;from 5 to 35 parts by weight of a metal-coated fiber (C);from 3 to 30 parts by weight of a filler in a scaly shape or an acicular shape (D), andfrom 0.05 to 5 parts by weight of polytetrafluoroethylene (E),wherein the thermoplastic resin (A) comprises a styrene resin or a styrene resin and a second thermoplastic resin, wherein the styrene resin is an ABS resin, an AES resin, an AAS resin or an MBS resin;the second thermoplastic resin is a polycarbonate resin or a polyamide resin; and the component (D) is a zinc oxide whisker. 2. A molding product formed of the resin composition according to claim 1. 3. The molding product according to claim 2, wherein the product has a volume resistance value of at most 100 Ω·cm. 4. A component or housing component product of an electrical or electronic device, comprising the molding product according to claim 2.
	description	The present invention relates to a grid holding device for a medical X-ray diagnostic system according to the preamble to claim 1, a grid device according to the preamble to claim 8, and X-ray diagnostic systems according to the preamble to claims 10 and 11, respectively. X-ray grids are used in X-ray diagnostic systems to reduce the noise occurring in a radiograph due to secondary radiation. An X-ray grid comprises a large number of slats of lead, which allow most of the primary radiation generated by an X-ray source to pass and which absorb most of the secondary radiation generated in an irradiated object. The grid is placed between the X-rayed object and the X-ray plate/film which is to be exposed. To function satisfactorily, the slats of an X-ray grid are often oriented such that their planes converge in a line located at a predetermined distance from the X-ray grid. This distance may be referred to as the convergence distance (or FFD=Film Focus Distance). If an X-ray source is placed in the above-mentioned line, the X-ray grid functions optimally, i.e. a maximum portion of the primary radiation is transmitted and a maximum portion of the secondary radiation is absorbed. It is desirable, however, to be able to use several different convergence distances in one and the same X-ray diagnostic system. For example, 80 cm may be a suitable distance for X-raying a patient's skull, 120 cm may be a suitable distance for X-ray diagnostics of internal organs of a patient in a horizontal position, and 180 cm may be suitable when X-raying the lungs of a patient in an upright position. An X-ray diagnostic system which is to be applicable to all three distances mentioned above may thus need three separate and replaceable grids to function optimally. Since the cost of an X-ray grid is very high, the system will be expensive to manufacture. Therefore, it has been suggested to use grids with variable convergence distances. U.S. Pat. No. 5,291,539 discloses a variable grid system in which two opposite edges of a grid structure are each fixed in a rotatable holder. In the flat state, the grid has a convergence distance of about 180 cm. By flexing the grid, this distance can be reduced. One drawback of such a technique is that a significant reduction of the convergence distance from 180 cm to, for example, 80 cm requires considerable flexing of the grid. Considerable flexing may result in the curvature of the grid not necessarily describing the circumferential surface of a circular cylinder, which means that the convergence distance will not be unambiguous, i.e. the planes of the slats will not coincide in a distinct line. If a grid is fixed in rotatable holders in this manner, it is also difficult or in any case time-consuming to remove the grid so that an exposure can be made without a grid. This is preferable in X-ray diagnostics of children, on the one hand, because in this case extra low radiation doses are desirable (elimination of the X-ray grid allows the radiation dose to be reduced to a third) and, on the other hand, because a child's skeleton generates relatively little secondary radiation. DE-C1-43 05 475 discloses another example of a grid system. In this document, use is made of a grid which in the flat state has parallel slats. Different flexed states of the grid are obtained by two opposite edges being loaded to a variable degree towards each other or by the grid being fixed over a vacuum chamber with variable pressure. This system also requires considerable flexing of the grid to obtain a short convergence distance. Also in this case, the grid has to be firmly fixed in its grid holder. One object of the present invention is to completely or partly eliminate the above-mentioned drawbacks. This object is achieved by means of a grid holding device for a medical X-ray diagnostic system according to claim 1, a grid device according to claim 8, and an X-ray diagnostic system according to claim 10 or 11. According to a first aspect, the invention, more specifically, relates to a grid holding device for a medical X-ray diagnostic system, which device is adapted to cooperate with a flexible, plate-shaped X-ray grid, which in a flat state has a first convergence distance, and which device comprises a flexing means for flexing the X-ray grid in order to adjust the convergence distance of the X-ray grid. The grid holding device is characterised in that the flexing means comprises a first means for flexing the X-ray grid in a first direction, from the flat state to a first predetermined flexed position in which the grid has a second convergence distance, which is longer than the first convergence distance, and a second means for flexing the X-ray grid in a second direction from the flat state to a second predetermined flexed position, in which the grid has a third convergence distance, which is shorter than the first convergence distance. With such a device, a great difference can be obtained between the shortest and the longest convergence distance, without considerable flexing of the grid being required. Instead, the grid is bent or flexed to a lesser extent, but in two different directions. Furthermore, the grid holder can be made compact. In a preferred embodiment, the first means for flexing comprises a first inflatable element with an elastic wall, which is arranged to exert a pressure, when the element is inflated, on one flat surface of the X-ray grid. When using such a holding device, a grid can easily be inserted and removed, since it does not have to be fixed by screws in the flexing means. Preferably, also the second flexing means comprises a corresponding, inflatable element, which acts on the other surface of the grid. The walls of these elements are preferably arranged to exert a pressure on the X-ray grid in an area, which is located about a centre line between two opposite edges of the grid, which yields an advantageous curvature of the grid. In a preferred embodiment, the grid holding device further comprises a box with a lid and a bottom, which are both X-ray transparent. The box is arranged to contain the X-ray grid and the first and the second flexing means. This results in a compact holding device which is easy to handle. Preferably, the grid holding device comprises at least a first and a second pair of resilient beads. The first bead in each pair is attached to the underside of the lid and the second bead in each pair is attached to the bottom of the box, opposite the first bead in the respective pairs. The pairs of beads can be arranged to fix the X-ray grid in the box. Using such a grid holding device, the grid can easily be removed when an exposure without a grid is desired. In one embodiment, the pressure can be variable in some of the beads. The beads on one side of the grid can then contribute to the curvature of the grid by loading the edges of the grid in the direction opposite to the direction in which the centre line of the grid is loaded by the inflatable elements on the opposite side. This allows an even more compact design of the grid box. According to a second aspect, the invention relates to a grid device, comprising a flexible, plate-shaped X-ray grid, which in a flat state has a first convergence distance, and a grid holding device as described above. Such a grid device gives the same advantages as the grid holding device. The first convergence distance of the grid device can preferably be in the range of 110–130 cm, the second convergence distance in the range of 170–190 cm and the third convergence distance in the range of 70–90 cm. According to a third aspect, the invention relates to an X-ray diagnostic system, which comprises a grid holding device as described above. According to a fourth aspect, the invention relates to an X-ray diagnostic system, which comprises a grid device as described above. The X-ray diagnostic systems according to the third and fourth aspects of the invention give the same advantages as the grid holding device and the grid device according to the invention. FIG. 1 schematically shows an X-ray system according to prior-art technique. Secondary X-ray radiation grids, hereinafter referred to as X-ray grids, are used in X-ray systems to obtain a more distinct image of an irradiated object. Usually an X-ray system is composed as schematically shown in cross-section in FIG. 1. A radiation source 101 emits X-ray radiation 102, which passes through an examined object 103, such as a human body, and reaches an X-ray film 104, which is exposed to the radiation. The intensity of the radiation which reaches the X-ray film 104 varies over the surface of the film depending on the characteristics of the inner structures of the object 103. If the object 103 is a human body, an image of the skeleton in the body can thus be recorded. The X-ray radiation 102 emitted by the radiation source 101 may be referred to as primary radiation. Such primary radiation can generate secondary radiation. This may occur if primary radiation excites an atom, for example, in a skeleton tissue in the object 103. This atom can then emit secondary radiation 105 in a random direction. If the secondary radiation reaches the X-ray film 104 noise occurs in the image, i.e. the image will be less clear. In order to shield the X-ray film 104 from such secondary radiation, an X-ray grid 106 is used, which is located in the vicinity of the film. The X-ray grid 106 is composed of a number of slats 107 of lead, which are spaced apart with the aid of spacers 108, which contrary to the slats 107 are made of a material which does not absorb X-rays. The grid thus resembles a stack of narrow strips of lead with spacers made of a material which does not absorb X-rays. In its assembled state, the X-ray grid 106 is composed of a plate with dimensions of, for example, 40×40 cm and a thickness of, for example, 2 mm. The cross-sectional long sides of the slats 107, which in FIG. 1 are also shown on a larger scale in cross-section perpendicular to their longitudinal direction, are oriented such that primary radiation 102, emitted directly from the radiation source 101, will propagate parallel with the planes of the slats 107. The secondary radiation 105, however, will be absorbed by the surfaces of the slats, except for the small portion of the secondary radiation 105 that is parallel with the primary radiation 102 in the plane of the cross-section. It is to be noted that also a small portion of the primary radiation 102 is absorbed by the X-ray grid, since the slats 107 have a certain thickness. To enable the system described above to function satisfactorily, the radiation source 101 has to be placed at a distance from the grid 106 that substantially corresponds to the convergence distance there of, i.e. at the distance from the grid (and on the correct side of the grid) where the planes of the slats coincide in a line. FIG. 2 is a cross-sectional view schematically showing the function of a grid device according to an embodiment of the invention. In this case, the grid can be flexed in two directions. When the grid is flat, as shown at 201, it has a first convergence distance 202, for example 120 cm. This corresponds to a first optimum positioning 203 of a radiation source. The grid holding device which supports the grid comprises flexing means, which will be described below, for flexing the grid in a first direction to a first predetermined flexed position, indicated by dashed lines at 204. In this position, the grid more or less approximately describes part of the circumferential surface of a circular cylinder having its centre line to the right of the grid in FIG. 2. In the position 204, the grid has a second convergence distance 205 (longer than the first one), for example 180 cm. At 206, a corresponding optimum positioning of a radiation source is shown. In this position, the slats of the grid are more parallel than in the flat initial position. The grid holding device also comprises flexing means for flexing the grid in a second direction opposite to the first direction to a second flexed position, indicated by dot-dashed lines at 207. In this position, the grid more or less approximately describes part of the circumferential surface of a circular cylinder having its centre line to the left of the grid in FIG. 2. In the position 207, the grid has a third convergence distance 209 (shorter than the first one), for example 80 cm. In this position, the slats of the grid are less parallel than in the initial position. At 209, a corresponding optimum positioning of a radiation source is shown. FIG. 3 is an exploded view of a grid holding device according to an embodiment of the invention. The device cooperates with a grid 301 accommodated in the grid holding device, which is in the form of a box with an X-ray transparent lid 302 and an X-ray transparent bottom 303. The walls of the box interconnecting the lid and the bottom are not shown. When used in an X-ray system, the box is placed between the object that is to be irradiated and the X-ray plate/film that is to be exposed. At the bottom 303 of the box, a first inflatable element 304 is placed, which in the inflated state exerts a load on the X-ray grid so as to flex the same in said first direction. The element 304 is arranged about a centre line 311 of the grid 301. A corresponding element 304′, which is indicated by dashed lines in FIG. 3, is arranged at the underside of the lid 302. This element 304′ serves to flex the grid in a second opposite direction. Six beads 305–310 are arranged at the bottom 303 of the box. Corresponding beads 305′–310′, which are indicated by dashed lines, are arranged at the underside of the lid 302. Each one of the beads 305–310 at the bottom of the box forms, together with the corresponding beads 305′–310′ at the underside of the lid, a pair of beads which serves to fix the grid 301 in the box. The beads are arranged to secure the grid 301 at the edges on both sides of the centre line 311. In this case, the beads are placed in the corners of the grid 301 and halfway between the corners at said edges, but it is also conceivable, for example, to combine the beads 305, 310 and 306 into one elongate bead extending along the entire edge. As an alternative to the beads, it is possible to use folds in the grid box, but in that case the grid 301 should be substantially centred between the lid 302 and the bottom 303 in its flat state. Furthermore, the grid should be pushed into the box in the longitudinal direction of the folds. FIG. 4a schematically shows a grid holding device corresponding to that shown in FIG. 3, which grid holding device is in a first position. In FIG. 4a, the device in FIG. 3 is seen along the centre line 311, from the edge of the device where the beads 305 and 307 are located, the wall interconnecting the lid and the bottom being removed. As already mentioned, the grid holding device comprises a lid 402 and a bottom 403. The grid 401 can be inserted and removed (pushed in or out) through an openable door 409 in the box. FIG. 4a shows how the beads 405 and 407 (corresponding to 305 and 307 in FIG. 3) cooperate with the other beads in the respective pairs 405′ and 407′ to resiliently hold and fix the grid 401 in the box. For this purpose, the beads are made of an elastic material. They can be filled with air or, for example, a foamed plastic material. In FIG. 4a, the upper beads 405′, 407′ in each pair are inflated, whereas the lower beads (405, 407) are more or less evacuated. In the shown example, the grid 401 is thus located in the vicinity of the bottom 403 of the box. It is also conceivable to centre the grid 401 in its flat position in a position halfway between the lid 402 and the bottom 403. In that case, the beads in each pair (for example 407, 407′) can have the same size, which makes it unnecessary to vary their size. The beads can then also be solid. The arrangement shown in FIG. 4a also gives the advantage that the bottom 403 prevents undesirable downward flexing of the grid 401 due to its own weight in the shown horizontal position. In FIG. 4a, the inflatable elements 404, 404′ are also shown. In the flat state, the grid has a convergence distance (FFD) of 120 cm. In FIG. 4b, the grid holding device in FIG. 4a is shown in a second position. The inflatable element 404 (corresponding to 304 in FIG. 3) is here shown in an inflated state. This element 404 can be made as a tight bag or balloon fixed to the bottom 403 of the box. Alternatively, it can be a membrane, whose edges are welded to the bottom 403 of the box, so that an air-tight space is formed. The element 404 comprises an elastic wall, which when the element is inflated is pressed against the grid 401 and flexes it. The element 404 is inflated, for example with air, through a hose (not shown). The upper beads 405′, 407′ are kept inflated. The grid 401 is thus flexed so that the centre line of the grid 401 is moved upwards in the Figure and the edges on both sides of the centre line are moved downwards. This is achieved by means of the inflatable element 404 and the beads 405′, 407′, and the grid 401 then has a convergence distance of 180 cm. The underside of the lid 402 of the box can optionally be provided with an abutment (not shown) in the form of a part of the circumferential surface of a circular cylinder. When the element 404 is heavily inflated, the grid is pressed against the abutment, thereby assuming a desirable shape. The extension of the inflatable element 404 in the plane of the bottom 403 can be adjusted to the bending stiffness of the grid 401 to provide a suitable effect over the width of the grid, thereby giving the grid an optimally flexed form. Another possibility is to arrange a plurality of inflatable elements which in the inflated state press against one surface of the grid 401 and preferably in the area round the centre line 311 shown in FIG. 3. The pressure in these elements can optionally be varied individually. In FIG. 4c, the grid holding device in FIG. 4a is shown in a third position. The inflatable element 404′ is now used like the element 404 in FIG. 4b. The element 404 which is inflated in FIG. 4b is here substantially void of air and does not affect the grid 401. At the same time, the lower beads (for example 405, 407) in each pair are inflated, so that the opposite edges of the grid on both sides of the centre line are moved towards the lid 402 of the box. The upper beads 405′, 407′ are substantially evacuated. This results in the grid 401 being flexed in a direction opposite to that in FIG. 4b. The convergence distance is now 80 cm. Summing up, the invention relates to a grid holder for an X-ray diagnostic system. The grid holder cooperates with a flexible X-ray grid, which in a flat state has a first focus distance/convergence distance of about 120 cm. A flexing means, preferably in the form of an inflatable element, which can exert a pressure on the surface of the grid, is arranged to flex the grid in a first direction to a first position in which it has a second convergence distance of about 180 cm. Another corresponding flexing means is arranged to flex the grid in the opposite direction to a second position in which it has a third convergence distance of about 80 cm. This allows variable convergence distances with minimum flexing of the grid. The invention also relates to grid devices with grid holders and grids as well as X-ray diagnostic systems comprising such grid holders/grid devices. The invention is not limited to the embodiments described above, but can be varied within the scope of the appended claims.
	abstract	The present invention includes a filtering apparatus for a CT imaging system or equivalently for an x-ray imaging system. The filtering apparatus may be translated along a first axis or a transverse axis to with respect to an attenuation pattern of a subject during an imaging session to reduce radiation exposure to anatomical regions of the subject sensitive to radiation exposure and/or regions from which data is not being acquired.
055770908	abstract	An x-ray apparatus and method for irradiating products, e.g. food, includes a hot electron plasma annulus confined by a simple magnetic mirror. The device includes a chamber for confining a gas, heated by microwave energy. The chamber has a central cylindrical opening into which the product is placed or conveyed through to receive x-rays radiating from the chamber. A number of chambers may be arranged coaxially in series to increase product throughput or arranged in an array to irradiate larger products.
	description	This application is a divisional of U.S. patent application Ser. No. 15/972,051, filed May 4, 2018, which is a continuation of PCT Application No. PCT/US16/61202, filed Nov. 9, 2016, which claims the benefit of priority under 35 USC 119(e) of U.S. Provisional Patent Application No. 62/252,664, filed Nov. 9, 2015, entitled “Radiation Shield Device And Method”, and of U.S. Provisional Patent Application No. 62/354,932, filed Jun. 27, 2016, entitled “Radiation Protection Device For X-Ray System Employing Discrete X-Ray Shielding Segments”. The contents of these documents are incorporated herein by reference in their entireties. The present invention, in some embodiments thereof, relates to radiation shielding (protecting), and more particularly, but not exclusively, to radiation shielding apparatuses and applications thereof. Exemplary embodiments of the invention relate to apparatuses (devices, systems), and methods, for shielding (protecting) surroundings around the periphery of a region of interest located inside an object (e.g., a patient) from radiation emitted by an X-ray system towards the object. Exemplary embodiments are applicable for shielding (protecting) medical personnel, and patients, from exposure to X-ray radiation during medical interventions or/and diagnostics. A radiation emitting system (for scanning, treatment, or diagnostics) includes a radiation emitting source positioned to oppose one side of an object, and a radiopaque plate or a radiation detector positioned on the opposite side of the object, for example. The radiation emitting source may be any device or mechanism which emits radiation, for example, electromagnetic radiation, such as X-rays or Gamma-rays, and the radiation detector may be any device or mechanism which detects the emitted radiation, including, but not limited, to an image intensifier, an analog circular detector device, and a rectangular digital detector. In medical imaging applications which include use of an X-ray system, the X-ray system typically generates real-time video or still images of one or more ‘regions of interest’ within the object (e.g., the body of a subject or patient). Such region(s) of interest is/are considered the areal target for directing the field of view of the X-rays. The X-ray source and the radiation detector are placed on opposite sides of the object (e.g., subject's body), across the region(s) of interest, usually mounted on both ends of a C-shaped arm. Often, the X-ray source is positioned below, and the radiation detector is positioned above, the subject's body. However, for some medical imaging applications, these positions may be reversed, or, alternatively, the X-ray system C-arm may be oriented at essentially any spatially (horizontally or vertically) oblique angle relative to the subject's body. In such applications, not all radiation emitted by the X-ray source reaches the radiation detector. For example, emitted radiation flux may spread or diffuse around the projection axis, radiation may leak (i.e., leakage radiation) from the X-ray source, or/and radiation may scatter, such as from the X-ray source, the radiation detector or/and from any object in the nearby vicinity of the X-ray source, such as the subject's body or/and the table (bed), or/and any other nearby object(s). Health care providers, and technical personnel, who operate X-ray systems on a regular basis are usually exposed to a cumulative dosage of radiation, and may be harmed by such cumulative X-ray exposure. In the field and art of medical imaging, there is an on-going need for techniques (equipment and methodologies) applicable for preventing, or at least minimizing, such cumulative radiation exposure, in order to eliminate, or at least reduce, health risks. Exemplary teachings in the field and art of the invention are provided in the following disclosures by the same applicant/assignee of the present invention: U.S. Pat. Nos. 8,439,564 and 8,113,713, the teachings of which are incorporated by reference as if fully set forth herein. In spite of these and other teachings in the field and art of the invention, there is on-going need for developing and practicing new or/and improved techniques (apparatuses and methods) of radiation shielding. The present invention, in some embodiments thereof, relates to radiation shielding (protecting), and more particularly, but not exclusively, to radiation shielding apparatuses and applications thereof. Exemplary embodiments of the invention relate to apparatuses (devices, systems), and methods, for shielding (protecting) surroundings around the periphery of a region of interest located inside an object (e.g., a patient) from radiation emitted by an X-ray system towards the object. Exemplary embodiments are applicable for shielding (protecting) medical personnel, and patients, from exposure to X-ray radiation during medical interventions or/and diagnostics. According to an aspect of some embodiments of the present invention, there is provided a radiation protection apparatus for shielding surroundings around the periphery of a region of interest located inside an object from radiation emitted by an X-ray system towards the object, the radiation protection apparatus comprising: at least one radiation shield assembly including a support base operatively connectable to a radiation source or a radiation detector of the X-ray system, and a plurality of radiation shield segments sequentially positioned relative to the support base, thereby forming a contiguous radiopaque screen configured for spanning at least partially around the region of interest periphery with an edge of the radiopaque screen opposing the object; wherein at least one of the radiation shield segments is individually, actively controllable to extend or contract to a selected length with a respective free end thereof in a direction away from or towards the support base, so as to locally change contour of the radiopaque screen edge. According to some embodiments of the invention, at least one of the radiation shield segments is longitudinally extendible or contractible. Optionally, the free end is positionable relative to other adjacent free ends along a common longitudinal axis. According to some embodiments of the invention, the radiation protection apparatus further comprises: a control unit, operatively connected to, and configured for controlling operation of, the at least one radiation shield assembly, and the at least one of the radiation shield segments, thereby defining positioning of at least one of the free ends relative to an opposing portion of the object. According to some embodiments of the invention, the control unit determines variable extensions of the radiation shield segments according to the selected length of the at least one of the radiation shield segments. According to some embodiments of the invention, the radiation protection apparatus further comprises: a drive mechanism, operatively connected to the radiation shield assembly and the control unit, and configured for extending or/and retracting a selected number of the radiation shield segments in accordance with the variable extensions determined by the control unit. According to some embodiments of the invention, the control unit determines the contour of the radiopaque screen edge correlatively with or/and in response to analysis of a surface curvature of the object. According to some embodiments of the invention, each of the radiation shield segments is individually extendable or retractable relative to the support base or/and relative to one or more others of the radiation shield segments. According to some embodiments of the invention, each of the radiation shield segments is individually powered by a global power supply, or by a local power supply. According to some embodiments of the invention, the global power supply is configured for globally providing power for operating all components of the radiation protection apparatus. According to some embodiments of the invention, the local power supply is configured for locally providing power for operating a separate unit or group of the radiation shield segments. According to some embodiments of the invention, the control unit includes a plurality of controllers, each of the controllers is configured for controlling a single separate unit or group of the radiation shield segments. According to some embodiments of the invention, the control unit is configured for globally controlling all separate units or groups of the radiation shield segments. According to some embodiments of the invention, the drive mechanism includes a plurality of drivers, each of the drivers is configured for extending or/and retracting a single separate unit or group of the radiation shield segments. According to some embodiments of the invention, the drive mechanism is configured for globally extending or/and retracting all separate units or groups of the radiation shield segments. According to some embodiments of the invention, the radiation source and the radiation detector define a beam axis extending therebetween, wherein each of the radiation shield segments is configured to be structurally rigid so as to retain a maximally extended shape along an extension axis that forms an elevation angle relative to direction of gravitational force acting upon the maximally extended shape. According to some embodiments of the invention, the elevation angle is 15 degrees or more, optionally particularly 30 degrees or more, optionally particularly 45 degrees or more, optionally particularly 90 degrees or more. According to some embodiments of the invention, the radiation protection apparatus further comprises a sensing unit operatively connected to the at least one radiation shield assembly. According to some embodiments of the invention, the sensing unit includes at least one positioning sensor coupled to at least one of the radiation shield segments and configured to sense and react to positioning or proximity of the at least one free end relative to the opposing portion of the object, or to a contact therebetween. According to some embodiments of the invention, the sensing unit includes at least one radiation detecting sensor configured to detect a portion of the radiation emitted by the radiation source and leaking through the plurality of radiation shield segments. According to some embodiments of the invention, the sensing unit is operatively connected to, and configured for providing data-information to, the control unit, whereby the control unit is responsive to the data-information provided by the sensing unit. According to some embodiments of the invention, each of the radiation shield segments comprises a plurality of overlapping radiopaque tiles, wherein extending and retracting of the radiation shield segments respectively decreases and increases extent of overlap between the radiopaque tiles. According to some embodiments of the invention, the radiation protection apparatus further comprises a data-information processing unit, operatively connected to, and configured for processing data-information associated with, the at least one radiation shield assembly and the control unit. According to some embodiments of the invention, the data-information processing unit is configured for determining reactive actuation parameters of at least one other of the radiation shield segments in response to the relative positioning of the at least one free end. According to some embodiments of the invention, the relative positioning relates to a maximally or/and minimally allowable distance between the free end and the opposing portion of the object. According to some embodiments of the invention, the relative positioning relates to a maximally allowable force measured when forcing the free end against the opposing portion of the object. According to some embodiments of the invention, the control unit is configured for controlling reactive actuation of at least one other of the radiation shield segments in response to the relative positioning of the at least one free end. According to some embodiments of the invention, extension of at least one other of the radiation shield segments changes, via the reactive actuation, in relation to a predetermined ratio of the extension and extension of the at least one of the radiation shield segments. According to some embodiments of the invention, at least one other of the radiation shield segments fully retracts in response to the reactive actuation. According to some embodiments of the invention, the radiation protection apparatus comprises a first radiation shield assembly including a first support base operatively connectable to the radiation source, and a second radiation shield assembly including a second support base operatively connectable to the radiation detector. According to some embodiments of the invention, the radiation protection apparatus further comprises an optical capturing device configured to capture images of at least some of the radiation shield segments or/and of the object. According to some embodiments of the invention, at least one free end is connected to a flexible spacer. According to some embodiments of the invention, the flexible spacer is configured to individually move relative to the at least one free end. According to some embodiments of the invention, the flexible spacer is configured to move according to at least one moving mode of bending, rotating, pivoting, and shifting away from alignment with the radiation shield segment connected thereto. According to some embodiments of the invention, the flexible spacer is configured such that the individual relative movement is facilitated in reaction to compressing against the object or/and conforming to the surface curvature of the object. According to some embodiments of the invention, the flexible spacer is configured to move according to a pre-calculated relative movement determined before contacting opposing boundary of the object. According to some embodiments of the invention, the flexible spacer is radiopaque to the radiation emitted by the X-ray system. According to some embodiments of the invention, the flexible spacer is configured for spacing or/and compressing between the at least one free end and relative to an opposing portion of the object, or/and to conform to a surface curvature of the object. According to some embodiments of the invention, at least one of the radiation shield segments includes: a radiopaque cover member ending with a cover member free end; a length dispenser operatively connected to the support base, the length dispenser is configured for covering a sector around the support base, and for controlling cover member length extending between the length dispenser and the cover member free end; and a first frame member operatively connected, via a first end thereof, to the length dispenser, and operatively connected, via a second end thereof, to the cover member free end, the first frame member is extendible or contractible according to control of the cover member length, and maintains structural rigidity sufficient for supporting the cover member in a laterally straight form along a chosen cover member deployed length. According to some embodiments of the invention, the cover member is configured in a form of a roller-shade such that a remaining non-deployed length of the cover member is rolled inside of the dispenser. According to some embodiments of the invention, the cover member is configured in a form of strips or tiles with selectively changeable overlapping, such that the cover member deployed length decreases by increasing overlapping between the strips or tiles. According to some embodiments of the invention, the drive mechanism is configured to force the cover member or/and the first frame member to extend or contract when shifting from the chosen cover member deployed length. According to some embodiments of the invention, the first frame member includes a plurality of first frame sections telescopically arranged and slidable inside one another or alongside one another. According to some embodiments of the invention, the first frame member extends along the cover member deployed length, thereby covering a first side of the cover member. According to some embodiments of the invention, the radiation protection apparatus further comprises a second frame member extendible or contractible along the chosen cover member deployed length and above a second side of the cover member, opposing the first side thereof. According to some embodiments of the invention, the radiation protection apparatus comprises a first and a second of the radiation shielding segments, juxtapositionally arranged, wherein the first radiation shielding segment is equipped with a first the cover member supported with the first frame member along a first adjacent side thereof, and the second radiation shielding segment is equipped with a second the cover member supported with the second frame member along a second adjacent side thereof, whereby the first radiation shielding segment adjacent side lies adjacent to the second radiation shielding segment adjacent side. According to some embodiments of the invention, the first frame member includes a lateral extension sized for covering a gap spanning between the first radiation shielding segment adjacent side and the second radiation shielding segment adjacent side, or/and for covering the second radiation shielding segment adjacent side. According to some embodiments of the invention, the second frame member is sized and shaped for mating against the lateral extension of the adjacent first frame member. According to some embodiments of the invention, the first frame member is slidably interconnected with the adjacent second frame member. According to an aspect of some embodiments of the present invention, there is provided an X-ray system comprising: a radiation source configured to emit radiation that is transmitted through an object and towards a radiation detector; and at least one radiation shield assembly comprising: a support base operatively connected to the radiation source or/and the radiation detector, and a plurality of individual radiation shield segments sequentially positioned relative to the support base; wherein each of the radiation shield segments is controllably, variably extendable or retractable between the radiation source or/and the radiation detector and the object. According to some embodiments of the invention, in the X-ray system, the plurality of radiation shield segments is configured for forming a contiguous radiopaque screen spanning at least partially around the X-ray system. According to an aspect of some embodiments of the present invention, there is provided a method of shielding surroundings from radiation emitted by an X-ray system externally positioned around the periphery of a region of interest located inside an object, the method comprising: providing at least one radiation shield assembly connectable to the X-ray system, the radiation shield assembly includes a support base operatively connectable to a radiation source or a radiation detector of the X-ray system, and a plurality of individually controllable radiation shield segments sequentially positioned relative to the support base and extendable towards the object; determining a chosen proximity of a free end of at least one of the radiation shield segments to an opposing portion of the object; and individually actuating, and extending or retracting one or more of the at least one radiation shield segments relative to the support base, until the free end is at the chosen proximity to the opposing portion of the object. According to some embodiments of the invention, the method further comprises: repeating the determining and the individual actuating of the at least one of the radiation shield segments, or/and of one or more others of the radiation shield segments, until collectively forming a contiguous radiopaque screen spanning at least partially around the periphery of the region of interest with an edge contoured correlatively with a surface curvature of the object. According to some embodiments of the invention, the determining is performed by using at least one positioning sensor configured for detecting positioning of at least one of the radiation shield segments relative to the object. According to some embodiments of the invention, the individually actuating is performed by using a drive mechanism configured for extending or/and retracting a selected number of the radiation shield segments in correlation to the position detecting. According to some embodiments of the invention, the method further comprises: using at least one radiation detecting sensor configured for detecting a portion of the radiation emitted by the radiation source and leaking through the contiguous radiopaque screen. According to some embodiments of the invention, the individually actuating is performed by using a drive mechanism configured for extending or/and retracting a selected number of the radiation shield segments in correlation to the radiation detecting. According to some embodiments of the invention, the determining is performed by using a data-information processing unit configured for processing data-information associated with the at least one radiation shield assembly. All technical or/and scientific words, terms, or/and phrases, used herein have the same or similar meaning as commonly understood by one of ordinary skill in the art to which the invention pertains, unless otherwise specifically defined or stated herein. Exemplary embodiments of technology, methods (steps, procedures), apparatuses (devices, systems, components thereof), equipment, and materials, illustratively described herein are exemplary and illustrative only and are not intended to be necessarily limiting. Although methods, apparatuses, equipment, and materials, equivalent or similar to those described herein can be used in practicing or/and testing embodiments of the invention, exemplary methods, apparatuses, equipment, and materials, are illustratively described below. In case of conflict, the patent specification, including definitions, will control. Implementation of some embodiments of the invention can involve performing or completing selected tasks manually, automatically, or a combination thereof. Moreover, according to actual instrumentation and equipment of some embodiments of the invention, several selected tasks could be implemented by hardware, by software, by firmware, or a combination thereof, using an operating system. The present invention, in some embodiments thereof, relates to radiation shielding (protecting) apparatuses and applications thereof. Exemplary embodiments of the invention relate to apparatuses (devices, systems), and methods, for shielding (protecting) surroundings around the periphery of a region of interest located inside an object (e.g., a patient) from radiation emitted by an X-ray system towards the object. Exemplary embodiments are applicable for shielding (protecting) medical personnel, and patients, from exposure to X-ray radiation during medical interventions or/and diagnostics. In medical imaging applications involving use of an X-ray system, not all radiation emitted by the X-ray source reaches the radiation detector, whereby some of the emitted X-ray radiation may impinge upon human subjects (e.g., health care providers, technical personnel, patients). Such exposure of human subjects to emitted X-ray radiation may cause substantially harmful health effects, especially, when exposure occurs on a repetitive basis, particularly, over long periods of time. In such medical imaging applications, there is an on-going need for techniques (equipment and methodologies) applicable for preventing, or at least minimizing, exposure of subjects to radiation exposure, in order to eliminate, or at least reduce, health risks. The term ‘X-ray system’, as used herein, in a non-limiting manner, refers to any radiography or radiotherapy X-ray emitting type system, such as digital radiology, fluoroscopy, or digital X-ray systems. X-ray system also refers to X-ray emitting type systems suitable for use in non-medical applications, such as security related applications. For purposes of further understanding exemplary embodiments of the present invention, in the following illustrative description thereof, reference is made to the figures (FIGS. 1 through 13). Throughout the following description and accompanying drawings, same reference numbers refer to same components, elements, or features. It is to be understood that the invention is not necessarily limited in its application to particular details of construction or/and arrangement of exemplary device, apparatus, or/and system components, set forth in the following illustrative description. The invention is capable of other exemplary embodiments or of being practiced or carried out in various ways. FIG. 1 schematically illustrates an exemplary C-arm type X-ray system 5 that is suitable for implementing exemplary embodiments of the present invention. X-ray system 5 includes a radiation source 8 and a radiation detector 6 mounted on opposite ends of a C-arm 9. C-arm 9 may be mounted on a mobile base with wheels or it may be mounted via a support arm to the floor or the ceiling of a fluoroscopy suite, or in any other manner. The object for the X-ray system operation is a subject 1 resting on a table 7. Subject 1 may refer to an entire human person or animal or to a portion (e.g. limb) thereof. Nevertheless, X-ray system 5 may be configured to scan any other type of object, including artifacts (for applications related to border control and customs, for example). In use, the radiation source 8 and radiation detector 6 are placed on opposite sides of the body of subject 1, for example, across a requested region of interest 4. Radiation source 8 emits an X-ray beam 2 that passes through the imaged object toward the radiation detector 6, which records the exposure to X-ray radiation and sends the image or video feed to a computer or/and display either in real time, or at a later time. Often, radiation source 8 is positioned below the patient and the detector 6 is positioned above, as shown, however for some applications these positions may be reversed or the C-arm 9 may be oriented at any spatially oblique angle. Beam 2 travels generally (in a conic dispersion) along a straight beam axis 3 which is geometrically defined as the line segment between the center of radiation source 8 and center of radiation detector 6, although not all emitted radiation reaches detector 6 and a residual dosage is commonly scattered at different angles, usually from subject 1 or table 7. Exemplary embodiments of the present invention relate to a radiation protection apparatus for shielding surroundings around the periphery of a region of interest 4 located inside an object (subject 1) from radiation emitted by an X-ray system (e.g., X-ray system 5) towards the object. In some embodiments, the radiation protection apparatus is structurally configured to operate at different angles around the object (subject 1) without loss of functionality. In exemplary embodiments, the radiation protection apparatus includes a radiation shield assembly having a plurality of radiation shield segments. In such embodiments, each of the radiation shield segments is optionally configured to be structurally rigid so as to retain a maximally extended shape along an extension axis that forms an elevation angle relative to the direction of gravitational force acting upon such a maximally extended shape. In exemplary embodiments, the elevation angle may be 15 degrees or more, optionally particularly 30 degrees or more, optionally particularly 45 degrees or more, optionally particularly 90 degrees or more. An aspect of some embodiments of the invention is provision of a radiation protection apparatus for shielding surroundings around the periphery of a region of interest located inside an object from radiation emitted by an X-ray system towards the object. In exemplary embodiments, the radiation protection apparatus includes: at least one radiation shield assembly including a support base operatively connectable to a radiation source or a radiation detector of the X-ray system, and a plurality of radiation shield segments sequentially positioned relative to the support base, thereby forming a contiguous radiopaque screen configured for spanning at least partially around the region of interest periphery with an edge of the radiopaque screen opposing the object. In exemplary embodiments, at least one of the radiation shield segments is individually, actively controllable to extend or contract to a selected length with a respective free end thereof in a direction away from or towards the support base, so as to locally change contour of the radiopaque screen edge. FIG. 2 schematically illustrates exemplary radiation protection apparatus 10 operatively connected to (and mounted on) exemplary X-ray system 5. Radiation protection apparatus 10 includes a first radiation shield assembly 11 disposed in a region of space between radiation detector 6 and table 7, and a second radiation shield assembly 13 disposed in a region of space between source 8 and table 7. Nevertheless, only a single radiation shield assembly may be used as part of radiation protection apparatus 10, for example in the region next to source 8 only. At least one radiation shield assembly (11 or/and 13) includes a support base 14 operatively connectable to radiation source 8 or radiation detector 6 of X-ray system 5. Support base 14 is optionally circumferential (e.g., in a form of ellipse, such as a circle, or in a form of tetragon, such as a parallelogram or a rectangle), although it may capture only one side or sector around radiation source 8 or radiation detector 6. A plurality of radiation shield segments 12 are sequentially positioned relative to support base 14, thereby forming a contiguous radiopaque screen 15 configured for spanning at least partially around the region of interest 4 periphery with a radiopaque screen edge 16 opposing the object (subject 1). In some embodiments, at least one of the radiation shield segments 12 is individually, actively controllable to extend or contract to a selected length with a respective free end 17 thereof in a direction away from or towards support base 14, so as to locally change contour of radiopaque screen edge 16. In some embodiments, each of the at least one of the radiation shield segments 12 is longitudinally extendible or contractible along a longitudinal axis of the respective radiation shield segment 12. In exemplary embodiments, the free end 17 of a respective radiation shield segment 12 is positionable relative to other adjacent free ends 17 along a common longitudinal (straight) axis. FIG. 3 schematically illustrates a plurality of exemplary radiation shield segments which may be included in exemplary embodiments of the radiation shield assembly, which, in turn, is included in exemplary embodiments of the radiation protection apparatus. In exemplary embodiments, the plurality of radiation shield segments is configured for forming a contiguous radiopaque screen with an edge contoured correlatively with a surface curvature of an object (subject). Theoretically, there is no limit on the number of radiation shield segments included in the radiation shield assembly. For example, the radiation shield assembly may include at least 1, or at least 2, or at least 3, or at least 4, or at least 5, or at least 10, or at least 15, or at least 20, radiation shield segments. In some embodiments, and as shown in FIG. 3, it may be advantageous to provide a greater number of radiation shield segments in order to increase accuracy (resolution) and close matching with free 17 ends can more closely match a surface curvature of the object. By providing the degree of freedom where the radiation shield segments are individually extendable (i.e. rather than constraining them so that differences in extensions of the radiation shield segments are fixed), this allows the ‘multi-segment’ shield assembly 11 to be operated so that the degree of extension of each segment closely matches an opposing surface (e.g. upper surface of subject 1) in a manner that minimizes the distance between the two. In many situations (e.g. where the upper surface of the subject 1 is quite irregular) this allows for an almost ‘seal’ between the upper surface of the subject 1 and contour of radiopaque screen edge 16, and therefore increases the effectiveness of the shields. By providing the degree of freedom where the radiation shield segments are individually extendable (i.e. rather than constraining them so that differences in extensions of the radiation shield segments are fixed), this allows the multi-segment shield to be operated so that the degree of extension of each segment closely matches an opposing surface (e.g. upper surface of subject 1) in a manner that minimizes the distance between the two. In some embodiments, it is possible for a user to manually configure the radiation shield segments 12 to a specific multi-extension-state of the multi-extension-state space. Alternatively or additionally, radiation shield 12 further includes a motorized system modifying degrees-of-extensions (e.g. measureable, for example, by a distance between a distal location of the radiation shield segment and a base location). In one example, each radiation shield segment 12 is associated with a different respective motor for moving the distal edge along beam axis 3 to increase (or decrease) an extension of the radiation shield segment. In another example, a single common motor suffices, and, for example, each radiation shield segment may be associated with a different respective clutch, and all clutches are associated with the common motor. In some embodiments, a sensor unit is provided to determine, for at least some of radiation shield segments, at least one of (i) a respective proximity between a respective fixed location on the radiation shield segment (e.g. distal end of a radiation shield segment) and a target surface; and (ii) an extent of contact between the respective distal end of the radiation shield segment and an opposing surface. In some embodiments, the output from the sensors may be used (e.g. via a control unit) to determine the extent of extension or retraction needed for one or more of the segments of one or more of the shields. Thus, in one non-limiting example, (i) at least one shield 12 starts out in retracted configuration and (ii) the motorized system extends each segment towards an opposing surface (e.g. an upper surface of subject 1, or a surface of table 7) until the segment contacts (or nearly contacts—e.g. within a distance of at most 15 cm or at most 10 cm or at most 3 cm or at most 2 cm or at most 1 cm or at most 5 mm or at most 3 mm or at most 1 mm) the opposing surface. In this case, sensor system measures the distance between a respective distal end of each radiation shield segment and in response to the output of the sensor unit, the motorized system continues to extend each radiation shield segment 12 until a distal end of the radiation shield segment respectively reaches the desired position. FIG. 4 schematically illustrates another exemplary embodiment of the radiation protection apparatus, and referenced as exemplary radiation protection apparatus 10′, highlighting exemplary apparatus components and operative connections thereof. Exemplary radiation protection apparatus 10′ corresponds to exemplary radiation protection apparatus 10 equipped with first radiation shield assembly 11 (although it may be equipped, also or instead, with second radiation shield assembly 13, for example). Radiation protection apparatus 10′ includes a control unit 18, operatively connected to, and configured for controlling operation of, first (or/and second) radiation shield assembly 11, and at least one of radiation shield segments 12, thereby defining positioning of at least one of free ends 17 relative to an opposing portion of the object (e.g., subject 1). Control unit 18 determines variable extensions of radiation shield segments 12 according to the selected length of the at least one of radiation shield segments 12. In this example, first radiation shield assembly 11 is shown in a particular setting configured for only partial angular coverage, which is less than 360 degrees, for example in order to avoid contact with patient's head or face. Each discrete radiation shield segment 12 is individually extendable or retractable from a location of support base 14. The presence of multiple segments that are individually extendable offers an additional degree-of-freedom—instead of the relative extension of each segment being fixed, it is possible to modify the relative extension. Exemplary radiation protection apparatus 10′ also includes a drive mechanism 19, operatively connected to first (or/and second) radiation shield assembly 11 and control unit 18, and configured for extending or/and retracting a selected number of radiation shield segments 12 in accordance with variable extensions determined by control unit 18. Control unit 18 optionally determines contour of radiopaque screen edge 16 correlatively with or/and in response to analysis of the surface curvature of the object. In some embodiments, each of the radiation shield segments 12 is individually extendable or retractable relative to support base 14 or/and relative to one or more other radiation shield segments 12. In some embodiments, a global power supply 20 may be used to power central parts of radiation protection apparatus 10′, while each of the radiation shield segments 12 may be individually powered by a local power supply (20A, 20B, and 20C, for example). Each local power supply is configured for locally providing power for operating a separate unit or group of radiation shield segments 12 (12A, 12B and 12C, respectively, in this example). Optionally, control unit 18 optionally includes a plurality of controllers (18A, 18B, and 18C, for example), each is configured for controlling a single separate unit or group of the radiation shield segments 12 (12A, 12B and 12C, respectively, in this example). Optionally, drive mechanism 19 includes a plurality of drivers (19A, 19B, and 19C, for example), each is configured for extending or/and retracting a single separate unit or group of the radiation shield segments 12 (12A, 12B and 12C, respectively, in this example). A data-information processing unit 21 may also be provided, being operatively connected to, and configured for processing data-information associated with, first (or/and second) radiation shield assembly 11 and control unit 18. Optionally, data-information processing unit 21 is configured for determining reactive actuation parameters of some of radiation shield segments in response to relative positioning of free end 17 of one or more others. The relative positioning of free end 17 may relate to a maximally or/and minimally allowable distance between free end 17 and the opposing portion of the object, or to a maximally allowable force measured when forcing free end 17 against the opposing portion of the object. Control unit 18 may be configured for controlling reactive actuation of some radiation shield segments (e.g., radiation shield segments 12C) in response to relative positioning of at least one free end 17 of other radiation shield segments (e.g., free end 17A of radiation shield segment 12A). Optionally, extension of these some radiation shield segments (12C, in this example) changes, via the reactive actuation, in relation to a predetermined ratio of extension and extension of the at least one of the other radiation shield segments (12A, in this example). In some such embodiments, radiation shield segments 12C fully retract in response to this reactive actuation to extension of radiation shield segment 12A, for example. Exemplary radiation protection apparatus 10′ may also include an optical capturing device 22 configured to capture images of at least some of radiation shield segments 12 or/and of the object (e.g., subject 1). The captured images may include any type of information which facilitates or assists in building representation of the surrounding environment, including information from visible light or/and from non-visible light (including, for example, ultrasonic means). Optionally, alternatively or additionally, exemplary radiation protection apparatus 10′ may further include a sensing unit (similar or identical to sensing unit 24 shown in FIG. 5, for example) that is operatively connected to at least one radiation shield assembly. In some embodiments, at least one free end 17 is connected to a flexible spacer 23, optionally radiopaque to the radiation emitted by the X-ray system, optionally configured for spacing or/and compressing between the at least one free end 17 and relative to an opposing portion of the object, or/and to conform to a surface curvature of the object. In some embodiments, flexible spacer 23 is configured to move or/and deform in accordance with opposing body surface curvature it meets. The flexible spacer 23 may be fixed in a chosen angle relative to the radiation shield segment it is connected to, and may be aligned or nonaligned with, so it may deform in accordance with surface curvature in contact. Optionally and alternatively, flexible spacer 23 is configured to individually move relative to the free end 17 it is connected to, such as by way of bending, rotating, pivoting, and shifting away from alignment with the radiation shield segment 12 connected thereto. Flexible spacer 23 may be ‘passive’ in the sense that it is configured such that any individual relative movement thereof is facilitated in reaction to compressing against the object or/and conforming to the surface curvature of the object. Optionally and alternatively, flexible spacer 23 may be ‘active’ in the sense that it is configured to move according to a pre-calculated relative movement determined before contacting opposing boundary of the object. FIG. 5 schematically illustrates another exemplary embodiment of the radiation protection apparatus, and referenced as exemplary radiation protection apparatus 10″, highlighting exemplary apparatus components and operative connects thereof. Exemplary radiation protection apparatus 10″ corresponds to exemplary radiation protection apparatus 10 equipped with second radiation shield assembly 13 (although it may be equipped, also or instead, with first radiation shield assembly 11, for example). Exemplary radiation protection apparatus 10″ includes a control unit 18, operatively connected to, and configured for controlling operation of, second (or/and first) radiation shield assembly 13, and at least one of radiation shield segments 12, thereby defining positioning of at least one of free ends 17 relative to an opposing portion of the object (e.g., subject 1). In this exemplary embodiment shown in FIG. 5, control unit 18 is configured for globally controlling all separate units or groups of radiation shield segments 12. Optionally, control unit 18 determines variable extensions of radiation shield segments 12 according to the selected length of at least one of radiation shield segments 12. Each discrete radiation shield segment 12 is individually extendable or retractable from a location of support base 14. Control unit 18 optionally determines contour of radiopaque screen edge 16 correlatively with or/and in response to analysis of the surface curvature of the object. In some embodiments, each of the radiation shield segments 12 is individually extendable or retractable relative to support base 14 or/and relative to one or more other radiation shield segments 12. Exemplary radiation protection apparatus 10″ also includes a drive mechanism 19, operatively connected to second (or/and first) radiation shield assembly 13 and control unit 18, and configured for extending or/and retracting a selected number of radiation shield segments 12 in accordance with variable extensions determined by control unit 18. Optionally, in this exemplary embodiment, drive mechanism 19 is configured for globally extending or/and retracting all separate units or groups of radiation shield segments 12, if and when required (and prescribed by control unit 18). In some embodiments, a global power supply 20 may be used to power central parts of radiation protection apparatus 10″, and optionally, in this exemplary embodiment, global power supply 20 is configured for globally providing power for operating all components of exemplary radiation protection apparatus 10″, if and when required, and according to control by control unit 18. A data-information processing unit 21 may also be provided, being operatively connected to, and configured for processing data-information associated with, second (or/and first) radiation shield assembly 13 and control unit 18. Optionally, data-information processing unit 21 is configured for determining reactive actuation parameters of some of radiation shield segments in response to relative positioning of free end 17 of one or more others. The relative positioning of free end 17 may relate to a maximally or/and minimally allowable distance between free end 17 and the opposing portion of the object, or to a maximally allowable force measured when forcing free end 17 against the opposing portion of the object. In some embodiments, at least one free end 17 is connected to a flexible spacer 23, optionally radiopaque to the radiation emitted by the X-ray system, optionally configured for spacing or/and compressing between the at least one free end 17 and relative to an opposing portion of the object, or/and to conform to a surface curvature of the object. In some embodiments, flexible spacer 23 is configured to move or/and deform in accordance with opposing body surface curvature it meets. The flexible spacer 23 may be fixed in a chosen angle relative to the radiation shield segment it is connected to, and may be aligned or nonaligned with, so it may deform in accordance with surface curvature in contact. Optionally and alternatively, flexible spacer 23 is configured to individually move relative to the free end 17 it is connected to, such as by way of bending, rotating, pivoting, and shifting away from alignment with the radiation shield segment 12 connected thereto. Flexible spacer 23 may be ‘passive’ in the sense that it is configured such that any individual relative movement thereof is facilitated in reaction to compressing against the object or/and conforming to the surface curvature of the object. Optionally and alternatively, flexible spacer 23 may be ‘active’ in the sense that it is configured to move according to a pre-calculated relative movement determined before contacting opposing boundary of the object. Exemplary radiation protection apparatus 10″ may further include a sensing unit 24 that is operatively connected to at least one radiation shield assembly (in variation 10″ to second radiation shield assembly 13, optionally also to first radiation shield assembly 11). In some embodiments, sensing unit includes at least one positioning sensor 25 coupled to at least one of radiation shield segments 12 and configured to sense and react to positioning or proximity of at least one free end 17 relative to opposing portion of the object, or to a contact therebetween. Optionally, alternatively or additionally, sensing unit 24 includes at least one radiation detecting sensor 26 configured to detect a portion of the radiation emitted by radiation source 8 (either directly or/and as scattered/residual radiation) and leaking through plurality of radiation shield segments 12. In some embodiments, sensing unit 24 is operatively connected to, and configured for providing data-information to, control unit 18. Optionally, control unit 18 is responsive to data-information provided by sensing unit 24. In some embodiments, exemplary radiation protection apparatus 10″ may also include an optical capturing device (similar or identical to optical capturing device 22 shown in FIG. 4, for example) configured to capture images of at least some of radiation shield segments 12 or/and of the object (e.g., subject 1). FIGS. 6A-6C schematically illustrate an exemplary radiation protection apparatus 30 positioned at different exemplary elevation angles. Exemplary radiation protection apparatus 30 may be identical or similar to herein illustratively described exemplary radiation protection apparatus 10 (FIG. 2), 10′ (FIG. 4), or 10″ (FIG. 5). In exemplary embodiments, exemplary radiation protection apparatus 30 is structurally and functionally configured to operate at different angles around the object, without loss of functionality. As shown in FIGS. 6A-6C, exemplary radiation protection apparatus 30 is operatively connected to (for example, by being mounted on) an X-ray system similar to X-ray system 5 (shown in FIGS. 1 and 2) with a radiation source 8 and a radiation detector 6 positioned at opposing ends of C-arm 9. Exemplary radiation protection apparatus 30 includes a first radiation shield assembly 31 disposed in a region of space between radiation detector 6 and the object, and a second radiation shield assembly 32 disposed in a region of space between source 8 and the object. At least one radiation shield assembly (31 or/and 32) includes a first support base 33, operatively connectable to (and, for example, mountable around) radiation source 8, and a second support base 33 operatively connectable to (and, for example, mountable around) radiation detector 6. A plurality of radiation shield segments 34 are sequentially positioned relative to support base 33, thereby forming a contiguous radiopaque screen 35 configured for spanning at least partially around periphery of a region of interest, within the object, with a radiopaque screen edge 36 opposing the object. In some embodiments, at least one of the radiation shield segments 34 is individually, actively controllable to extend or contract to a selected length with a respective free end 37 thereof in a direction away from or towards support base 33, so as to locally change contour of radiopaque screen edge 36. In exemplary embodiments, radiation source 8 and radiation detector 6 define beam axis 3 extending therebetween. Optionally, each of radiation shield segments 34 is configured to be structurally rigid so as to retain (up to) a maximally extended shape along an extension axis (which is substantially parallel to beam axis 3) that forms an exemplary elevation angle 38 relative to direction 39 of gravitational force (‘gravity vector’) acting upon the maximally extended shape. Optionally, alternatively or additionally, radiation shield segments 34 are angled relative to beam axis 3. Exemplary elevation angle 38 may be, for example, 15 degrees or more, optionally, particularly 30 degrees or more, optionally particularly 45 degrees or more, or optionally particularly 90 degrees or more. FIG. 6A illustrates an example where the beam axis 3 is oriented substantially vertically. In different embodiments, and as shown in FIGS. 6B and 6C, for example, the orientation of beam axis 3 is modifiable, for example, by motion of C-arm 9 in different spatial angles, or, for example, by motion of the radiation source 8 relative to the radiation detector 6. FIG. 6B illustrates exemplary elevation angle 38 of about 45 degrees relative to the vertical gravity vector 39. FIG. 6C illustrates exemplary elevation angle 38 of nearly 90 degrees relative to the vertical gravity vector 39. In some embodiments, the orientation of beam axis 3 is modifiable. In exemplary embodiments of radiation shield assembly 31 or/and 32, structural rigidity for each given radiation shield segment 34, or for a group of such radiation shield segments 34, is sufficient to retain the shape of each radiation shield segment throughout an exemplary elevation angle range of at least D degrees. In exemplary embodiments, D has a value of at least 10 degrees, or at least 15 degrees, or at least 20 degrees, or at least 25 degrees, or at least 30 degrees, or at least 45 degrees, or at least 60 degrees. In some embodiments, by having sufficient rigidity for each radiation shield segment to retain its shape this prevents or mitigated shape-deformations which may block the image beam. In some embodiments, the term ‘structural rigidity’ refers to how each radiation shield segment is constructed—i.e. design, material, geometry (e.g. thickness), for example. In contrast, any other type of radiation shield constructed from highly flexible radiation shield segments, for example, the shield segments could ‘bend’ or sag under its own weight. An aspect of some embodiments of the invention is a method of shielding surroundings from radiation emitted by an X-ray system externally positioned around the periphery of a region of interest located inside an object. FIG. 7A is a flow diagram of an exemplary embodiment (indicated as, and referred to by, reference number 50), including the indicated exemplary steps (procedures/processes) thereof, of such a method 50 of shielding surroundings from electromagnetic emitted by an X-ray system, such as X-ray system 5 (or X-ray system 30). Herein, the exemplary embodiment 50 of a method of shielding surroundings from radiation emitted by an X-ray system externally positioned around the periphery of a region of interest located inside an object is also referred to as the radiation shielding method. The exemplary embodiment 50 of the radiation shielding method presented in FIG. 7A, in a non-limiting manner, is implementable using various types of X-ray systems, such as exemplary X-ray system 5 (FIG. 1), or exemplary X-ray system 30 (FIGS. 6A-6C). Similarly, various types of X-ray systems, such as exemplary X-ray system 5 (FIG. 1), or exemplary X-ray system 30 (FIGS. 6A-6C), in a non-limiting manner, are usable for implementing exemplary embodiments of the radiation shielding method, such as exemplary embodiment 50 of the radiation shielding method presented in FIG. 7A. As shown in FIG. 7A, in a non-limiting manner, and in some embodiments, such as exemplary embodiment 50, the radiation shielding method includes the following exemplary steps (procedures/processes). In 52, there is providing at least one radiation shield assembly connectable to the X-ray system. The radiation shield assembly includes a support base operatively connectable to (and, for example, mountable around) a radiation source or a radiation detector of the X-ray system. The radiation shield assembly also includes a plurality of individually controllable radiation shield segments sequentially positioned relative to (for example, around) the support base and extendable towards the object. In 54, there is determining a chosen proximity of a free end of at least one of the radiation shield segments to an opposing portion of the object. Chosen proximity may also include ‘zero’ proximity, which means direct contact with the object, optionally at a chosen magnitude of force within an acceptable range of forces, applied or developed therebetween. In 56, there is individually actuating, and extending or retracting one or more of the at least one radiation shield segments relative to the support base, until the free end is at the chosen proximity (including ‘zero’ proximity) to the opposing portion of the object. In exemplary embodiments, such as in exemplary embodiment 50, the radiation shielding method additionally includes one or more of the following exemplary steps (procedures). The following exemplary steps (procedures) may be performed prior to, during, or/and after, performing any of steps (procedures) 52, 54, and 56. In exemplary embodiments, all of the following exemplary steps (procedures) are performed before (i.e., prior to) performing step (procedure) 52 of exemplary embodiment 50 of the radiation shielding method. Setting up and preliminary testing of the X-ray system 5 and any of its components, including but not limited to radiation source 8 and radiation detector 6. Defining the region of interest 4 within the object (subject 1) and its periphery, so that the X-ray system 5 can effectively image (or treat) a target anatomic location or organ within the periphery and across the area defining that region of interest 4. Marking chosen margins radially away from the region of interest 4 periphery, above or around which the radiopaque screen 15, formable by radiation protection apparatus 10′, can be later mounted. Positioning the object (subject 1) for effectively utilizing the X-ray system (on top of bed 7), in a manner by which the radiation protection apparatus 10′ can be applied to shield surroundings from around the region of interest 4 periphery, optionally above or around the marked margins allocated thereto. Connecting (e.g., by way of mounting) or verifying connection of first and second radiation shield assemblies 13 and 11 to X-ray system 5, by which support base 14 of each of the radiation shield assemblies is operatively connected to (for example, and positioned around) radiation source 8 and radiation detector 6, respectively, and that the plurality of individually controllable radiation shield segments 12 are sequentially positioned relative to each support base 14 and extendable towards the object (subject 1). In exemplary embodiments, such as in exemplary embodiment 50, the radiation shielding method may further include at least one of the followings steps (procedures), not necessarily in the following order. Determining a chosen proximity of free end 17 of at least one of the radiation shield segments 12 to an opposing portion of the object. Determining the chosen proximity (including ‘zero’ proximity) may be performed by using at least one positioning sensor 25 configured for detecting positioning of at least one of radiation shield segments 12 relative to the object. The determining may be performed by using a data-information processing unit 21. Individually actuating one or more of radiation shield segments 12 relative to respective support base 14, until that free end 17 is at the chosen proximity to the opposing portion of the object. The individually actuating may be performed by using drive mechanism for extending or/and retracting a selected number of the radiation shield segments 12 in correlation to the detected position. Optionally, repeating the determining or/and the individual actuating of that at least one radiation shield segments 12, or/and of one or more others radiation shield segments 12, until collectively forming a contiguous radiopaque screen 15 spanning at least partially around the periphery of the region of interest 4 with an edge 16 contoured correlatively with a surface curvature of the object. Using at least one radiation detecting sensor 26 for detecting leakage of portion of the radiation emitted by radiation source 8 through the contiguous radiopaque screen 15, and optionally controlling the drive mechanism in accordance with results of the radiation detecting. Programming or applying one or more pre-sets readily programmed in radiation protection apparatus 10′ or/and X-ray system 5 which optionally limits automatic or/and bounded activity of at least one radiation shield segment 12, or/and an interrelated sequence of some or all radiation shield segments 12. A first exemplary pre-set may include recognition of a particular anatomic location or organ (e.g., head of subject 1 or hands of any of the medical personnel), or of certain artifacts (e.g., medical apparatuses or tools), which will affect limited extension or full retraction of one or more radiation shield segments 12 in order to avoid contact or collision, or prevent undesired shielding or motion in its premises, for example. A second preliminary pre-set may include certain covering schemes of particular sectors around region of interest periphery, so, for example, one scheme may include full or partial extension of several sequential radiation shield segments 12 thereby forming contiguous radiopaque screen 15 spanning less than 360 degrees (optionally 180 degrees or less, or optionally 90 degrees or less) around the region of interest 4 periphery (one example is shown in FIG. 4, where first radiation shield segment 12A is fully extended, and adjacent second radiation shield segment 12B is partially extended, while other (optionally, rest) of the radiation shield segments 12C are fully retracted. Another exemplary scheme may include one or more (adjacent or remote) radiation shield segment 12 be substantially or fully retracted, among fully (including substantially) extended other radiation shield segments 12, with free ends 17 thereof approximating body of object, in order that medical personnel can reach the region of interest directly via these formed gaps. A third preliminary pre-set may include prescribed partial (moderate or substantial) or full retraction of one or more (e.g., all) radiation shield segments 12 upon or during shift of C-arm 9, radiation detector 6, radiation source 8, or/and bed 7, for example, relative to the object (subject 1 or particularly region of interest 4). One such pre-set, for example, may dictate full retraction of some or all radiation shied segments 12 during substantial shift (for example, repositioning of C-arm 9 relative to subject 1). Another such pre-set, for example, also known as “hover mode”, may dictate moderate retraction (relative or fixed) of some or all radiation shield segments 12 during slight repositioning of bed 7 relative to radiation source 8, for example. FIG. 7B is a flow chart of an exemplary routine (process) for a shield in ‘hover mode’ to regulate a gap distance between a distal end of radiation shield segments and a target or opposing surface may be regulated to a non-zero set-point value. In exemplary step (procedure) S101, for each given radiation shield segment, a sensing system is operated to monitor a respective non-zero radiation shield segment: target surface gap-distance. A common sensing system may sense the distances for multiple radiation shield segments or/and each radiation shield segment may be associated with its own respective segment-specific sensing system. In exemplary step (procedure) S105, for each radiation shield segment it is determined (e.g. by electronic circuitry—for example, software executing on a digital computer) if the respective gap-distance deviates from it's set-point value. This may be due to a number of causes (or combinations of causes) including but not limited to: (i) a change in the setpoint value (e.g. the user may wish to cause the shield to ‘hover at a greater distance’ or ‘lesser distance’ and may input this information via a Graphical User Interface (GUI)); (ii) motion of the opposing or target surface, motion of radiation source 8 or/and detector 6; (iii) motion of an ‘observer’ (e.g. a person in the room); (iv) rotation of the C-arm; (v) Table adjustment and (iv) a change in an operating mode. In one example related to ‘motion of an observer’ there may be a single person in the room other than subject 1—e.g. only one medical member (physician) in the room. In one example, the physician may stand on one side of the table or another. In another example, there may be a need to provide absolute 360 degrees shielding (e.g. contact between the radiation shield segments and the opposing surface or a ‘small gap distance’) only for the side of the table where the physician is located—for patient comfort, radiation shield segments on the other side of the table may be operated in ‘hover mode’ at a larger gap distance. In this example, when the physician walks from one side of the table to the other, the radiation shield (i.e. according to input from sensor system and actuating by the drive mechanism) detects this and responds by: (i) reducing the gap distance (or even leaving hover mode to the radiation shield segments contact subject 1) on the side of the table to which the physician is walking; and (ii) increasing the gap distance on the side of the table to which the physician is leaving. In exemplary step (procedure) S109, in response to a detected deviation between respective gap-distance for a given radiation shield segment (e.g. as detected by the detection system) the drive mechanism modifies an extension state of one or more radiation shield segments to reduce or eliminate, for each given radiation shield segment, a respective deviation between (A) the respective measured gap distance between a location on the given radiation shield segment and the opposing surface and (ii) a respective set-point gap distance for the given radiation shield segment. Thus, if the deviation as measured in steps (procedures) S101-S105 is ‘positive’ (i.e., the gap distance exceeds its set-point value), the drive mechanism would operate to reduce the gap distance to reduce or eliminate the deviation—i.e. by increasing an extension state of a radiation shield segment to move location(s) on the radiation shield segment towards the opposing surface. If the deviation as measured in steps (procedures) S101-S105 is ‘negative’ (i.e., the gap distance is less than its set-point value), the drive mechanism would operate to increase the gap distance to reduce or eliminate the deviation—i.e. by decreasing an extension state of a radiation shield segment to move location(s) on the radiation shield segment away the opposing surface. Thus, FIG. 7B is a flow chart describing a method (process) of regulating radiation shield segment-specific gap distances to a common set-point value or to a different set-point values where each radiation shield segment is regulated to a different set-point value. This is performed according to measured distances, i.e., either via direct distance measurement or via measurement of an ‘indication’ of distance between a location on the radiation shield segment and the opposing surface. The ‘opposing surface’ may be a common ‘target’ surface for multiple radiation shield segments or each radiation shield segment may be associated with a different respective opposing/target surface. Some embodiments of the invention relate to a radiation protection apparatus for an X-ray system that includes an X-ray source and detector defining a beam axis therebetween. In exemplary embodiments, the radiation protection apparatus includes a first radiation shield assembly having a support base located at one end of the beam axis. In exemplary embodiments, the first radiation shield assembly includes a first plurality of (X-ray opaque) radiation shielding segments disposed at different locations around the beam axis to collectively form an X-ray opaque screen, wherein each of the radiation shielding segments is individually extendable from and retractable towards the support base location along the beam axis, to provide a hovering mode according to the following technical features and characteristics. In exemplary embodiments, the radiation protection apparatus further includes a sensing unit configured to sense a respective proximity between a respective point on each radiation shielding segment and a respective target surface. In exemplary embodiments, the radiation protection apparatus further includes a controller configured to receive proximity data from the sensing unit. In exemplary embodiments, the radiation protection apparatus further includes a drive mechanism configured for extending or/and retracting radiation shielding segments of the plurality of radiation shielding segments in response to output of the controller. In exemplary embodiments, the controller operates the drive mechanism in accordance with the proximity data received from the sensing unit so as to extend or/and retract the segments. In exemplary embodiments, for each given radiation shielding segment, the controller is configured to regulate a gap distance between (i) a respective point of the given segment and (ii) a respective target surface, to a respective pre-determined value. FIGS. 8A-8B schematically illustrate side views of an exemplary (discrete) radiation shield segment 100 of an exemplary radiation protection apparatus which may be similar in function or/and structure to radiation protection apparatus 10, 10′, 10″, or 30, for an X-ray system, such as X-ray system 5. In exemplary embodiments, radiation shield segment 100 includes a radiopaque cover member 101 which may be configured to prevent from passing thereacross (e.g., across thickness thereof) over 10%, optionally over 25%, optionally over 50%, optionally over 75%, or optionally over 90%, of radiation flux originating from the X-ray system. In some embodiments, radiopaque cover member 101 is substantially flexible so it can bend, curve or/and be rolled (such as in/around a drum). In exemplary embodiments, radiation shielding segment 100 further includes a length dispenser 102 mountable on the X-ray system to cover a particular sector around a radiation source (e.g., radiation source 8) or radiation detector (e.g., radiation detector 6) of the X-ray system. In some embodiments, dispenser 102 is configured for changing or/and maintaining a deployed length 103 of cover member 101 between dispenser 102 and a free end 104 of cover member 101 (from within a range of deployed lengths). Cover member 101 is optionally arranged (as shown) in a form of a roller-shade, such that a remaining non-deployed length thereof is rolled in dispenser 102. In exemplary embodiments, radiation shield segment 100 may further include a (laterally rigid) first frame member 106 that is connected with a first end 107 thereof to dispenser 102, and connected with a second end 108 thereof to cover member free end 104. In some embodiments, first frame member 106 is extendible or contractible (between a fully expanded form as indicated in FIG. 8A and a fully retracted form as indicated in FIG. 8B) to allow spanning of the deployed length 103 (or any deployed length from within the range of deployed lengths), while maintaining structural rigidity sufficient to support cover member 101 in a lateral straighten form along its deployed length 103. First frame member 106 optionally includes a plurality of first frame sections 106i telescopically arranged and slidable inside one another. First frame member 106 may be extended or extendable along the deployed length 103 (or any deployed length from within the range of deployed lengths) thereby covering a first (lateral) side 110 of cover member 101. In exemplary embodiments, radiation shield segment 100 may include a (laterally rigid) second frame member 111 being extendible or collapsible to allow deployed length 103 from (or any deployed length from within the range of deployed lengths). Second frame member 111 may be extended or extendable along the deployed length 103 above a second (lateral) side 112 of cover member 101, opposing first side 110 thereof. Second frame member 111 optionally includes a plurality of second frame sections 111i telescopically arranged and slidable inside one another. In exemplary embodiments, radiation shielding segment 100 further includes a controller 105 that is operatively linked to length dispenser 102 and is configured to actuate dispenser 102 or/and to control extent of the deployed length 103, according to a selected extent. In exemplary embodiments, radiation shield segment 100 further includes an actuator 109 that is configured to force cover member 101 or/and first frame member 106 or/and second frame member 111 to extend or contract when shifting from deployed length 103 within the range of deployed lengths. In some embodiments, actuator 109 is configured to act against a continuous pulling force (for example, generated by a returning spring acting on the drum, the frame or/and the cover member), thereby forcing together the flexible cover member into a substantially spatial straight form (to avoid sagging, for example). Actuator 109 is operatively connected to a contact sensor 113 configured to indicate a magnitude of force or/and pressure developing or affecting shielding segment 100 or members thereof. Optionally, alternatively or additionally, actuator is operatively connected to a proximity sensor 114 configured to indicate a distance from a motion resisting object, which may be a bed, a body part of a subject (human or animal patient, for example), as indicated in FIG. 2, or others. In exemplary embodiments, radiation shield segment 100 further includes a flexible radiopaque spacing member 116 that is connected to cover member free end 104, and is configured for spacing or/and compressing between cover member free end 104 and a motion resisting object. Optionally, alternatively or additionally, spacing member 116 is configured to conform to shaped surface of the motion resisting object. In an exemplary embodiment, the spacing member is in a form of a flap, such that each radiation shield segment has a respective flexible or/and individually deployable flap attached to a distal end thereof. For example, deploying the segment to a target surface (e.g. the subject being imaged or/and the table) may entail multistage operation—after the radiation shield segment is in place (i.e. at its proper multi-extension state) the flap may be deployed to the target surface—e.g. so that a flat surface of the flap is flush against the target surface. FIGS. 9A-9B schematically illustrate top views of an exemplary (discrete) radiation shield segment 100, and an exemplary assembly of such (discrete) radiation shield segments, respectively. As shown in FIG. 9B, a number of radiation shield segments 100 are interconnected to form an encircling coverage which can be part of the radiation protection apparatus provided around a radiation source or/and a radiation detector of the X-ray system. Each pair of radiation shield segments 100 (e.g., a first 100a and a second 100b radiation shield segments 100) are juxtapositionally arranged (horizontally or vertically, or in any angle). First radiation shield segment 100a is equipped with a first cover member 101a supported with first frame member 106 along a first adjacent side 110a thereof. Second radiation shield segment 100b is equipped with a second cover member 101b supported with second frame member 111 along a second adjacent side 112b thereof. First radiation shield segment adjacent side 110a lies adjacent to second radiation shield segment adjacent side 112b, as shown. As shown, first frame member 106 includes a lateral extension 117 sized for covering a seam (or a gap) 118 between first radiation shield segment adjacent side 110a and second radiation shield segment adjacent side 112b and for covering second radiation shield segment adjacent side 112b. Second frame member 111 is sized and shaped for mating against lateral extension 117 of adjacent first frame member 106. Each discrete radiation shield segment may include interconnection means at both sides thereof which are configured to prevent lateral or sideways relative movement but to allow longitudinal or up-and-down relative movement, of each discrete radiation shield segment relative to all other radiation shield segments. As shown, each discrete radiation shield element 100 includes a number of carriers 119, each is part of or fixated via a stem 120 to a corresponding second frame section 111i. Each carrier 119 is sized and shaped for sliding in a track facilitated by a rail 121 (e.g. in a form of a cavity) being part of or connected to first frame member 106. Carriers 119, stems 120 and rail 121 are shaped, sized and configured not to interfere with the ability of the frame members to extend or contract within defined limits, as demonstrated for example in FIGS. 8A-8B. An aspect of some embodiments of the invention is provision of an X-ray system including: a radiation source configured to emit radiation that is transmitted through an object and towards a radiation detector; and at least one radiation shield assembly including: a support base operatively connected to the radiation source or/and the radiation detector, and a plurality of individual radiation shield segments sequentially positioned relative to the support base. In such exemplary embodiments, each of the radiation shield segments is controllably, variably extendable or retractable between the radiation source or/and the radiation detector and the object. In such exemplary embodiments of an X-ray system, the plurality of radiation shield segments is configured for forming a contiguous radiopaque screen spanning at least partially around the X-ray system. FIGS. 10A-10H schematically illustrate an exemplary X-ray system 250 to which is operatively connected (and mounted) an exemplary radiation protection apparatus 260 including a plurality of exemplary discrete radiation shield segments 200 having a radiopaque cover member in a form of a roller-shade, and assemblies thereof. X-ray system 250 may be similar in function or/and structure to X-ray system 5, and include a radiation source 251 and radiation detector 252 at both ends of a C-arm 253, capable of shifting in between different angles and positions relative to a bed 254. A subject (patient) 255, being the object of the X-ray system, can lay on bed 254, and C-arm 253 be so positioned, such that a region of interest 256 is provided in between radiation source 251 and radiation detector 252. Radiation protection apparatus 260 may be similar in function or/and structure to any of radiation protection apparatus 10 and radiation protection apparatus 30, and include a first radiation shield assembly 262 disposed in a region of space between radiation detector 252 and table 254, and a second radiation shield assembly 251 disposed in a region of space between radiation source 261 and table 254. Nevertheless, only a single radiation shield assembly may be used as part of radiation protection apparatus 260, for example only in the region next to radiation source 251. At least one radiation shield assembly (261 or/and 262) includes a support base 263 operatively connectable to radiation source 252 or radiation detector 251 of X-ray system 250. Support base 263 is optionally circumferential and rectangular, as shown in FIG. 10B, although it may capture only one side or sector around radiation source 251 or radiation detector 252 and be in a different form, such as of ellipse, circle, or a different form of tetragon. A plurality of radiation shield segments 200 are sequentially positioned relative to support base 263, thereby forming a contiguous radiopaque screen configured for spanning at least partially around the periphery or region of interest 256, with a radiopaque screen edge opposing the object (subject 255). Any of radiation shield assemblies 261 and 262 can include any number of radiation shield segments 200 at any of its faces (sides) and in total. FIG. 10B shows radiation shield assembly 262 with three radiation shield segments 200 at each face, while FIG. 10F illustrates another variation of radiation shield assembly 262 with four radiation shield segments 200 at each face. In some embodiments, at least one of the radiation shield segments 200 is individually, actively controllable to extend or contract to a selected length with a respective free end thereof in a direction away from or towards support base 263. In some embodiments, the radiation shield segments 200 are extendible or contractible longitudinally. In exemplary embodiments, radiation shield segment 200 includes a radiopaque cover member 201 which may be similar in function or/and structure to radiopaque cover member 101 (showing only its deployed length section, for demonstrative purposes). In some embodiments, radiopaque cover member 201 is substantially flexible so it can bend, curve or/and be rolled (such as in a drum). Radiopaque cover member 201 may be dispensed or deployed via a dispenser 202 or by other means mountable on the X-ray system to cover a particular sector around an X-ray source or detector of the X-ray system. The dispenser may be controlled by use of a controller, and actuated by use of an actuator, as previously described. Cover member 201 is optionally arranged in a form of a roller-shade, such that a remaining non-deployed length thereof is rolled in drum provided with dispenser 202, for example. In exemplary embodiments, discrete radiation shield segment 200 includes a first frame member 206 which is extendible or contractible in accordance with selected deployed length of the cover member 201. First frame member 206 includes a plurality of first frame sections 206i telescopically arranged and slidable inside one another. First frame member 206 covers both sides of a first side 210 of cover member 201, allowing sliding motion thereof relative to frame section 206i excluding the final (most inner) section which is connected to a free end 204 of cover member 201. In exemplary embodiments, discrete radiation shield segment 200 includes a second frame member 211 being extendible or collapsible together with first frame member 206, above a second side 212 of cover member 201. Second frame member 211 includes a plurality of second frame sections 211i telescopically arranged and slidable inside one another. Second frame member 211 may be shaped and sized to mate geometrically with a recess 203 (as shown for example in FIG. 10D) provided along first frame member 206 in order to allow integration between adjacent discrete shielding segments while covering gaps or/and seams therebetween, using both frame members (for example, as shown in FIG. 10H). FIG. 10D shows a top view of exemplary discrete radiation shield segment 200 portion shown in FIG. 10C, presenting the concentric arrangement of all first and second frame sections. FIG. 10E(I) shows radiation shield segment 200 fully compacted while FIG. 10E(II) shows radiation shield segment 200 fully extended, together with cover member 201, first frame member 206 and second frame member 211. FIG. 10F shows radiation shield assembly 262 with a number of shielding segments 200 interconnected to form surrounding cover. Each pair of radiation shield segments (e.g., a first 200A and a second 200B radiation shield segments 200) are juxtapositionally arranged (horizontally or vertically, or in any angle). FIG. 10G shows one side of radiation shield assembly 262. As shown, each radiation shielding segment is fully individually controlled and can be deployed to a length independently of other radiation shielding segments, however the frame members of both sides of each radiation shield segment bridge across and cover any gap or seam through which unnecessary radiation can infiltrate through. In some embodiments, these frame members also contribute to the mechanical, functional and aesthetic behavior of the radiation protection apparatus, as they maintain the cover members substantially spread in both lateral (vertical) and horizontal axes, and themselves provide coverage in between adjacent cover members. FIGS. 11A-11C schematically illustrate an exemplary radiation shield assembly 300 which includes a plurality of exemplary discrete radiation shield segments 301. Exemplary radiation shield assembly 300 may be part of a radiation protection apparatus, optionally, similar in function or/and structure to any of radiation protection apparatus 10, radiation protection apparatus 30, or radiation protection apparatus 260. Each radiation shield segment 301 includes a radiopaque cover member 302 arranged in a form of overlapping strips 303 (e.g., tiles). In some embodiments, radiopaque cover member 302 is substantially rigid, or alternatively, it may be substantially flexible so it can be bent or curved. An actuator 304 with scissors mechanism (pantograph) 305 is used for extending (FIG. 11C) or contracting (FIG. 11B) the cover member 302. A deployed length L of cover member 302 is determined according to extent of overlapping between each two adjacent strips 303, such that increasing overlapping will cause decreased deployed length and vice versa. This type of radiation shield segment may be assembled with extendable-contractible frame members such as previously described in order to provide lateral support to the strips 303 and in order to cover any gap or seam between adjacent shielding segments. Optionally, additionally or alternatively, scissors mechanism 305 functions or includes or is configured for connecting to one or more extendable-contractible frame member. Alternatively, a frame member may be formed as scissors mechanism while cover member 302 is deployed or withdrawn using other means such as a dispenser (e.g., dispenser 202 shown in FIG. 10E). FIGS. 12A-12E schematically illustrate an exemplary (discrete), optionally, rigid, radiation shield segment 400 suitable for inclusion in any of the herein illustratively described exemplary embodiments of a radiation shield assembly, of any of the herein illustratively described exemplary embodiments of a radiation protection apparatus. In exemplary embodiments, the radiation protection apparatus may be similar in function or/and structure to any of exemplary radiation protection apparatus 10, exemplary radiation protection apparatus 30, or exemplary radiation protection apparatus 260, and may be similar in function or/and structure to exemplary radiation shield segments 100, or exemplary radiation shield segments 200, or exemplary radiation shield segments 301. The radiation shield segment 400 includes a first (single) frame member 401 formed of telescopically arranged frame sections 401i. In order to provide strength and structural support for entire radiation shield segment 400, frame member 401 may be formed of a high strength or/and a rigid material, while providing sufficient radiopacity due to high density characteristics. Such materials may include, as an example, tungsten, lead, or stainless steel alloys. A singular frame member section 401i is shown assembled in FIG. 12C and disassembled into main parts (‘exploded view’) in FIG. 12D. Each frame section 401i includes two lateral flanges 403 connected with a wedge 404 from a first side, and connected at second side with both (lateral) ends of a section 405i of a radiopaque cover member 405, provided in a form of tile (rigid, semi-rigid or flexible). Wedge 404 may optionally include a concavity 406 shaped to increase strength and structural stability to the frame section, and also accurately dimensioned to a minimal clearance and precise guiding for accurate engagement with other frame sections telescopically arranged therewith. Concavity 406 of each frame section 401i may house an insert-plate 407 having a smooth surface, and optionally made of a stiff/rigid material, configured for reducing friction between moving surfaces of telescopically interconnected frames or/and for increasing strength and structural stability to the frame section. In some embodiments, each radiopaque cover member section 405i is substantially rigid, or alternatively, it may be substantially flexible so it can be bent or curved or rolled. An actuator 408 (in a form of a motor, with or without a drive train) is operatively connected with scissors mechanism (pantograph) 409 and together are applicable for extending or contracting the radiation shield segment 400 with cover member 405. A deployed length L of cover member 405 is determined according to extent of overlapping between each two adjacent sections (tiles) 405i, such that increasing overlapping will cause decreased deployed length and vice versa. Flanges 403 are shaped with lateral extensions which are shaped and sized to cover any gap or seam between adjacent radiation shield segments of both sides thereof. Each flange 403 includes a protruding portion 410 and a recess portion 411, shaped and arranged such that protruding portion 410 can mate geometrically with recess portion 411, when laterally aligned and engaging therewith. FIG. 12E shows interconnection of a frame member section 401a of a first shielding segment 400a with an adjacent frame member section 401b of a second shielding segment 400b (similar to engagements/interconnections of radiation shield segments as shown, for example, in FIGS. 4, 9B, 10D, 10E and 11A). As shown, a protruding portion 410a of first shielding segment 400a mates geometrically with (e.g., nests in) a recess portion 411b of second radiation shield segment 400b, in order to allow integration between adjacent discrete radiation shield segments while covering gaps or/and seams therebetween, using both frame members. In some such embodiments (and as shown, for example, in FIG. 12E), when protruding portion 410a completely or at least partially nests in recess portion 411b, it is also connected thereto with a connecting force, such as by use of magnetic or electromagnetic generated force field. For example, first frame member section 401a includes a magnetizing element 412 and second frame member section 401b includes a ferromagnetic element 413, whereby the magnetizing element may be a permanent magnet or an electromagnet, for example. Optionally, additionally or alternatively, magnetizing element 412 and a ferromagnetic element 413 may be formed or/and arranged as part of an electromagnetic brake system which may operate (connect/disconnect) automatically or selectively by a user. FIGS. 13A-13B schematically illustrate an exemplary discrete radiation shield segment 500 operational with an exemplary push-strip (or push-wire) 503. Radiation shield segment 500 is shown as a singular manually operational model although it may be adapted to assemble with other similar radiation shield segments or/and be connected to an automatic/computerized control unit, drive mechanism, sensors, and the like, as previously described. Radiation shield segment 500 includes a first (single) frame member 501 including a plurality of telescopically arranged frame sections 501i, which may extend from a collapsed form (as shown in FIG. 13A) to an extended form (FIGS. 13B and 13C). Each frame section 501i is stiff enough to maintain shape thereof, and provides sufficient opacity. A flexible radiopaque cover member 502 is configured to roll or unroll from a drum 504 into a chosen length, required/requested for shielding surrounding around periphery of a region of interest in an object. A couple of push-strips 503 is coupled to or embedded in cover member 502, at both (lateral/rolled) sides thereof, as shown in FIG. 13C (which uncovers one push-strip 503 by illustratively clearing some frame sections 501i). The push-strips 503 are flexible enough in one axis, allowing it to roll with minimal resistance, together with cover member 502, but also are stiff enough and withstand substantial compression stress along its length. Hence, it can be pushed against a restraining (compressing) force while maintaining a straight form, unless it encounters a yielding force which may force it into collapsing. In some embodiments, a drive mechanism 505 in a form of a rotor (shown as a manually operational revolving handle, for illustrative purposes) is operatively coupled with one or both push strips 503 for actuating the entire radiation shield segment 500 into extension (by revolving the rotor in a first direction, thereby unrolling the push strips 503 with cover member 502) or contraction (by revolving the rotor in an opposite direction, thereby rolling the push strips 503 with cover member 502 back on drum 504). Push strips 503 may be formed of elastic strips of spring steel, relaxed in spiral (rolled) form. In this exemplary embodiment, although not necessarily, the rigid frame members 501 are configured only to provide lateral or other rigidity to the entire shield member 500, allowing it to align in different elevation angles without compromise in structure or/and function, as previously described. A return spring 506 coupled to drum 504 may be used to assist or resist rotor 505 when extending (unrolling) radiation shield segment 500 thereby making it ‘normally rolled’ or ‘normally unrolled’ if needed. Each of the following terms written in singular grammatical form: ‘a’, ‘an’, and ‘the’, as used herein, means ‘at least one’, or ‘one or more’. Use of the phrase ‘one or more’ herein does not alter this intended meaning of ‘a’, ‘an’, or ‘the’. Accordingly, the terms ‘a’, ‘an’, and ‘the’, as used herein, may also refer to, and encompass, a plurality of the stated entity or object, unless otherwise specifically defined or stated herein, or, unless the context clearly dictates otherwise. For example, the phrases: ‘a unit’, ‘a device’, ‘an assembly’, ‘a mechanism’, ‘a component’, ‘an element’, and ‘a step or procedure’, as used herein, may also refer to, and encompass, a plurality of units, a plurality of devices, a plurality of assemblies, a plurality of mechanisms, a plurality of components, a plurality of elements, and, a plurality of steps or procedures, respectively. Each of the following terms: ‘includes’, ‘including’, ‘has’, ‘having’, ‘comprises’, and ‘comprising’, and, their linguistic/grammatical variants, derivatives, or/and conjugates, as used herein, means ‘including, but not limited to’, and is to be taken as specifying the stated component(s), feature(s), characteristic(s), parameter(s), integer(s), or step(s), and does not preclude addition of one or more additional component(s), feature(s), characteristic(s), parameter(s), integer(s), step(s), or groups thereof. Each of these terms is considered equivalent in meaning to the phrase ‘consisting essentially of’. The term ‘method’, as used herein, refers to a single step, procedure, manner, means, or/and technique, or a sequence, set, or group of two or more steps, procedures, manners, means, or/and techniques, for accomplishing or achieving a given task or action. Any such herein disclosed method, in a non-limiting manner, may include one or more steps, procedures, manners, means, or/and techniques, that are known or readily developed from one or more steps, procedures, manners, means, or/and techniques, previously taught about by practitioners in the relevant field(s) and art(s) of the herein disclosed invention. In any such herein disclosed method, in a non-limiting manner, the stated or presented sequential order of one or more steps, procedures, manners, means, or/and techniques, is not limited to that specifically stated or presented sequential order, for accomplishing or achieving a given task or action, unless otherwise specifically defined or stated herein, or, unless the context clearly dictates otherwise. Accordingly, in any such herein disclosed method, in a non-limiting manner, there may exist one or more alternative sequential orders of the same steps, procedures, manners, means, or/and techniques, for accomplishing or achieving a same given task or action, while maintaining same or similar meaning and scope of the herein disclosed invention. Throughout this disclosure, a numerical value of a parameter, feature, characteristic, object, or dimension, may be stated or described in terms of a numerical range format. Such a numerical range format, as used herein, illustrates implementation of some exemplary embodiments of the invention, and does not inflexibly limit the scope of the exemplary embodiments of the invention. Accordingly, a stated or described numerical range also refers to, and encompasses, all possible sub-ranges and individual numerical values (where a numerical value may be expressed as a whole, integral, or fractional number) within that stated or described numerical range. For example, a stated or described numerical range ‘from 1 to 6’ also refers to, and encompasses, all possible sub-ranges, such as ‘from 1 to 3’, ‘from 1 to 4’, ‘from 1 to 5’, ‘from 2 to 4’, ‘from 2 to 6’, ‘from 3 to 6’, etc., and individual numerical values, such as ‘1’, ‘1.3’, ‘2’, ‘2.8’, ‘3’, ‘3.5’, ‘4’, ‘4.6’, ‘5’, ‘5.2’, and ‘6’, within the stated or described numerical range of ‘from 1 to 6’. This applies regardless of the numerical breadth, extent, or size, of the stated or described numerical range. Moreover, for stating or describing a numerical range, the phrase ‘in a range of between about a first numerical value and about a second numerical value’, is considered equivalent to, and meaning the same as, the phrase ‘in a range of from about a first numerical value to about a second numerical value’, and, thus, the two equivalently meaning phrases may be used interchangeably. For example, for stating or describing the numerical range of room temperature, the phrase ‘room temperature refers to a temperature in a range of between about 20° C. and about 25° C.’, and is considered equivalent to, and meaning the same as, the phrase ‘room temperature refers to a temperature in a range of from about 20° C. to about 25° C.’. The term ‘about’, as used herein, refers to ±10% of the stated numerical value. The phrase ‘operatively connected’ (or ‘operatively connectable’), as used herein, equivalently refers to the corresponding synonymous phrases ‘operatively joined’ (or ‘operatively joinable’), and ‘operatively attached’ (or ‘operatively attachable’), where the operative connection, operative joint, or operative attachment, is according to a physical, or/and electrical, or/and electronic, or/and mechanical, or/and electro-mechanical, manner or nature, involving various types and kinds of hardware or/and software equipment and components. It is to be fully understood that certain aspects, characteristics, and features, of the invention, which are, for clarity, illustratively described and presented in the context or format of a plurality of separate embodiments, may also be illustratively described and presented in any suitable combination or sub-combination in the context or format of a single embodiment. Conversely, various aspects, characteristics, and features, of the invention which are illustratively described and presented in combination or sub-combination in the context or format of a single embodiment, may also be illustratively described and presented in the context or format of a plurality of separate embodiments. Although the invention has been illustratively described and presented by way of specific exemplary embodiments, and examples thereof, it is evident that many alternatives, modifications, or/and variations, thereof, will be apparent to those skilled in the art. Accordingly, it is intended that all such alternatives, modifications, or/and variations, are encompassed by the broad scope of the appended claims. All publications, patents, and or/and patent applications, cited or referred to in this disclosure are herein incorporated in their entirety by reference into the specification, to the same extent as if each individual publication, patent, or/and patent application, was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this specification shall not be construed or understood as an admission that such reference represents or corresponds to prior art of the present invention. To the extent that section headings are used, they should not be construed as necessarily limiting.
060404914	claims	1. A method for dewatering and containing radioactive, aqueous waste, comprising the steps of: introducing radioactive, aqueous waste into a filtration container, the filtration container being an inner sack having a bottom provided with a straining cloth; dewatering the waste in the inner sack such that substantially all dewatering of the waste is carried out through the straining cloth; recirculating filtration water resulting from dewatering the waste through the waste in the inner sack for cleaning of the filtration water; sealing the inner sack after dewatering the waste; and disposing of dewatered waste in a disposable container structure including the inner sack holding the dewatered waste and an outer container enclosing the inner sack. a disposable container structure including a collecting container for receiving filtration water resulting from dewatering waste in the inner sack; suspension means for suspending the inner sack and the waste therein above the collecting container; and means for recirculating filtration water intercepted by the collecting container through the waste in the inner sack, 2. A method as claimed in claim 1, wherein recirculation of the filtration water includes pumping the filtration water from a collecting container disposed below the inner sack to a sprinkler disposed above the inner sack and distributing the filtration water over the waste in the inner sack with the sprinkler. 3. method as claimed in claim 2, comprising the further step of applying a negative pressure to an outside of the of the inner sack. 4. A method as claimed in claim 1, comprising the further step of applying a negative pressure to an outside of the bottom of the inner sack. 5. A method as claimed in claim 4, wherein the dewatering includes a first step of suspending the inner sack holding the waste above a collecting container for collecting the filtration water, and a second step of moving the inner sack to a station separate from the collecting container and drip-dewatering the inner sack and applying a negative pressure to an outside of the bottom of the inner sack. 6. A method as claimed in claim 1, wherein the outer container is a carrying outer sack. 7. A method as claimed in claim 6, comprising the further step of sealing the inner sack in a watertight sack before enclosing the inner sack in the outer container. 8. A method as claimed in claim 6, comprising the further step of applying a negative pressure to an outside of the bottom of the inner sack. 9. An apparatus for dewatering and containing radioactive, aqueous waste, comprising: 10. An apparatus as claimed in claim 9, further comprising means for applying a negative pressure to an outside of the bottom of the inner sack. 11. An apparatus as claimed in claim 10, wherein the means for applying a negative pressure comprises a suction box which is separate from the collecting container and which includes a supporting surface for supporting the inner sack and at least one opening formed in the supporting surface and in communication with a negative pressure source. 12. An apparatus as claimed in claim 10, wherein the outer container is a sack. 13. An apparatus as claimed in claim 10, wherein the inner sack is provided with lifting eyes at its open end for cooperating with the suspension means for suspension of the inner sack relative to the collecting container (20). 14. An apparatus as claimed in claim 10, wherein the inner sack is provided with a bottom reinforcement arranged on an outside of the straining-cloth bottom and connected to sides of the inner sack. 15. An apparatus as claimed in claim 10, wherein the inner sack has a volume of approximately 1 m.sup.3. 16. An apparatus as claimed in claim 9, wherein the outer container is a sack. 17. An apparatus as claimed in claim 16, wherein the outer sack is provided with lifting eyes at an open end thereof. 18. An apparatus as claimed in claim 9, wherein the inner sack is provided with lifting eyes at its open end for cooperating with the suspension means for suspension of the inner sack relative to the collecting container (20). 19. An apparatus as claimed in claim 18, further comprising means for applying a negative pressure to an outside of the of the inner sack. 20. An apparatus as claimed in claim 9, wherein the inner sack is provided with a bottom reinforcement arranged on an outside of the straining-cloth bottom and connected to sides of the inner sack. 21. An apparatus as claimed in claim 9, wherein the inner sack has a volume of approximately 1 m.sup.3.
	summary
	description	FIG. 1 is selective view of a related art nuclear core shroud 10, useable in a nuclear reactor like a BWR. Core shroud 10 may be positioned in a downcomer annulus region 20, which is an annular space formed between shroud 10 and an inner wall of a reactor pressure vessel (not shown) that receives fluid coolant flow and directs it downward for entry at a bottom of core 30. Shroud 10 may be a cylindrical structure surrounding core 30 that partitions the reactor into these downward and upward coolant flows on opposite radial sides of shroud 10. One or more jet pump assemblies 40 may line annulus 20 and direct coolant flow in this manner. After being directed downward past core shroud 10, coolant may then flow up through core 30 inside shroud 10. Core 30 is typically populated by several fuel assemblies (not shown) generating heat through nuclear fission during operation, and the coolant exiting core 30 may be quite energetic and potentially boiling. This energetic fluid flows up through and out of core 30 and shroud 10, potentially into steam separating and drying structures and ultimately to a turbine and generator that converts the energy from the steam flow into electricity. A top portion 15 of shroud 10 may terminate below such drying structures, and various core equipment may rest on or join to shroud 10 about top portion 15, which may be called a steam dam. One or more protrusions or obstacles 16, such as steam dam gussets, seismic pins, or lugs, may be aligned about top portion 15 of shroud 10 to support or join a shroud head (not shown), chimney, or drying structures. During a reactor outage, such as a refueling outage or other maintenance period, the reactor vessel may be opened and inspected, and internal structures of vessel may be removed. During an outage, loading equipment such as a bridge and trolley above the reactor, and 20-30 feet above core 30 and shroud 10, may move and load new fuel assemblies in core 30. Similarly, worker platforms may be installed about partial perimeters of the vessel for handling tools and inspections about the reactor periphery. Visual inspections of shroud 10, core 30, and/or any other component can be accomplished with video or camera equipment operated from the bridge or other loading equipment above the reactor during this time. Example embodiments include devices useable for inspection or tooling in a nuclear reactor with accurate positioning and non-interference with other reactor internals or refueling activities. A base inspection assembly, useable as a peripheral assembly on a steam dam or other nuclear reactor component, may clamp to various structures within the nuclear reactor and be moveable, with a handling rod, local motors, or other drive, around a perimeter of the reactor. A positioning assembly may be supported by the base inspection assembly and include rollers that rotate against a mast to relatively move the positioning assembly with respect to the inspection assembly and/or mast. Rollers may mesh or grip on sides of the mast to move along the same while rotating with minimal slippage or disconnection during operation. The rollers may be powered locally, such as with a motor, or externally, through a transmission that drives one or more of the rollers to rotate. The rollers may selectively bias against the mast to achieve engagement and disengagement from the same, such as with an expander that pushes one or more rollers to the mast when expanded. The rollers and mast are further rotatable relative to the base inspection assembly. For example, a sun gear secured to the base inspection assembly may provide an exterior surface about which the mast and rollers can revolve. If the sun gear is annular or includes an opening, the mast may extend through a center of the same and rotate on an axis of the sun gear, mast, and rollers. A local motor or external drive may provide power for this rotation and/or revolving. Any instrument, such as a camera, welding tool, cleaning sprayer, laser, ultrasonic tester, etc. can be joined to the mast and/or positioning assembly and be selectively moved and rotated by the same. Because this is a patent document, general, broad rules of construction should be applied when reading it. Everything described and shown in this document is an example of subject matter falling within the scope of the claims, appended below. Any specific structural and functional details disclosed herein are merely for purposes of describing how to make and use examples. Several different embodiments and methods not specifically disclosed herein may fall within the claim scope; as such, the claims may be embodied in many alternate forms and should not be construed as limited to only examples set forth herein. It will be understood that, although the ordinal terms “first,” “second,” etc. may be used herein to describe various elements, these elements should not be limited to any order by these terms. These terms are used only to distinguish one element from another; where there are “second” or higher ordinals, there merely must be that many number of elements, without necessarily any difference or other relationship. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of example embodiments or methods. As used herein, the term “and/or” includes all combinations of one or more of the associated listed items. The use of “etc.” is defined as “et cetera” and indicates the inclusion of all other elements belonging to the same group of the preceding items, in any “and/or” combination(s). It will be understood that when an element is referred to as being “connected,” “coupled,” “mated,” “attached,” “fixed,” etc. to another element, it can be directly connected to the other element, or intervening elements may be present. In contrast, when an element is referred to as being “directly connected,” “directly coupled,” etc. to another element, there are no intervening elements present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). Similarly, a term such as “communicatively connected” includes all variations of information exchange and routing between two electronic devices, including intermediary devices, networks, etc., connected wirelessly or not. As used herein, the singular forms “a,” “an,” and the are intended to include both the singular and plural forms, unless the language explicitly indicates otherwise. Indefinite articles like “a” and “an” introduce or refer to any modified term, both previously-introduced and not, while definite articles like “the” refer to the same previously-introduced term. It will be further understood that the terms “comprises,” “comprising,” “includes,” and/or “including,” when used herein, specify the presence of stated features, characteristics, steps, operations, elements, and/or components, but do not themselves preclude the presence or addition of one or more other features, characteristics, steps, operations, elements, components, and/or groups thereof. The structures and operations discussed below may occur out of the order described and/or noted in the figures. For example, two operations and/or figures shown in succession may in fact be executed concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved. Similarly, individual operations within example methods described below may be executed repetitively, individually or sequentially, so as to provide looping or other series of operations aside from single operations described below. It should be presumed that any embodiment or method having features and functionality described below, in any workable combination, falls within the scope of example embodiments. The Inventor has newly recognized that visual inspection of a nuclear reactor core from refueling equipment several feet above the core, such as a refueling bridge, trolley, crane, peripheral platform, etc., using cameras or other video capture equipment supported by such refueling equipment results in inferior inspection. For example, vibrations from trolley movement or operating equipment—or even personnel footfalls on the bridge—can cause a camera, supported by the trolley while extending dozens of feet down into a reactor core, to lose picture quality and verifiable position through such vibration. Movement and distance of the refueling equipment further compounds difficulty in verifying position of any camera or other inspection device, like an ultrasonic tester, with respect to object being inspected. Thus, inspections conducted from refueling equipment and reactor platforms several feet above a reactor during an outage typically require several different position verification mechanisms and avoidance of movement or vibration by personnel, or inspections must be repeated until satisfactory. The Inventor has further newly recognized that inspection and tool-usage activities in a nuclear power plant when performed above and radially offset from a target, such as from a refueling bridge or reactor perimeter, interferes with effective tool usage because the target is not directly below the operator. In such circumstances, the operator may be required to lean over and/or adopt a skewed working trajectory with the tool, which complexifies visuals and makes exact radial or vertical positioning of the target, and the user relative to the target, difficult to determine. Example embodiments described below address these and other problems recognized by Inventors with unique solutions enabled by example embodiments. The present invention is maneuvering devices useable in nuclear reactors and similar environments. In contrast to the present invention, the few examples discussed below illustrate just a subset of the variety of different configurations that can be used as and/or in connection with the present invention. Co-owned US Patent Publication 2017/0140844 published May 18, 2017 to Kelemen is incorporated herein by reference in its entirety. FIGS. 2 and 3 are illustrations of an example embodiment inspection assembly 100 useable in nuclear reactors. As shown in FIG. 2, assembly 100 is useable in conjunction with steam dam 15 at a top of a core shroud, such as shroud 10 in FIG. 1. Assembly 100 is shown again in FIG. 3 without steam dam 15, with directions that illustrate movements assembly 100 may be capable of on steam dam 15 (FIG. 2). Example embodiment assembly 100 may removably join to steam dam 15 and be moveable about the same to inspect equipment and reactor components from steam dam 15. For example, assembly 100 may include one or more top rollers 150 that allow assembly 100 to vertically seat on an edge or flange of steam dam 15 and move circumferentially (direction 215 in FIG. 3) along steam dam 15 while top rollers 150 rotate. Because steam dam 15 may be relatively fixed and close to structures in a core of a nuclear reactor, example embodiment assembly 100 may be advantageously positioned at verifiable and constant vertical positions from such structures by top roller 150 rolling on steam dam 15, as well as being angularly moveable along steam dam 15 to other desired positions. Top rollers 150 may be freely or selectively rotatable and even driven by a local motor or via a mechanical drive to facilitate desired movement or static positioning in the circumferential direction (direction 215 in FIG. 3). Example embodiment assembly may further include structures that removably join to an edge or flange of steam dam 15 to secure assembly 100 at a desired radial position. For example, one or more pairs of clamping rollers may join to a flange of steam dam 15 from which obstacles 16, including gussets, lugs, seismic pins, and other structures protrude. As shown in FIG. 4, paired interior clamp roller 161 and exterior clamp roller 162 may engage opposite vertical sides of steam dam 15. Paired interior and exterior rollers 161 and 162 allow assembly 100 to radially seat on an edge or flange of steam dam 15 and move circumferentially (direction 215 in FIG. 3) along steam dam 15 by rotation of rollers 161 and 162. This engagement may further facilitate positioning of assembly 100 at verifiable and constant radial positions (direction 290 is radial in FIG. 3) from structures via interior and exterior clamp rollers 161 and 162 rolling on steam dam 15. Rollers 161 and 162 may be freely or selectively rotatable and even driven by a local motor or via a mechanical drive in order to facilitate desired movement or static positioning in the circumferential direction (direction 215 in FIG. 3). An example of a mechanical drive useable to rotate rollers 161 and 162 is described further below in connection with FIG. 4. Example embodiment inspection assembly 100, although potentially moveable in other directions, may remain static in a radial direction (direction 290 in FIG. 3) while mounted to steam dam 15. In this way example assembly 100 may be continuously positioned with steam dam 15, and inspection of any structures with example embodiment assembly 100 may be verified with a known relation to steam dam 15. Interior clamp roller 161 and exterior clamp roller 162 may forcefully seat against opposite sides of steam dam 15 to secure assembly 100 in a radial direction (direction 290 in FIG. 3). For example, as shown in FIG. 2, exterior roller 162 may be connected to a rotatable biasing arm 110 that swings about a pivot point 165 so as to move exterior roller 162 about pivot point 165 in direction 210 (FIG. 3). Interior roller 161 may be near or directly on an axis of pivot point 165, such that exterior roller 162 can torque or clamp against steam dam 15 with interior roller 161. Such spacing may create a torque arm between interior roller 161 at pivot point 165 and exterior roller 162, preventing both radial movement of assembly 100 as well as rotation of assembly 100 in the 210 direction (FIG. 3). Of course, other joining structures may selectively mate example assembly 100 with steam dam 15, including spring-based roller clamps, or elastic or mechanical clamps and attachments. Any structure that joins example embodiment assembly 100 to steam dam 15 may be selectively disengaged to avoid obstacles 16 or account for other structures that may interrupt movement along steam dam 15 in an angular direction (direction 215 in FIG. 3). Such disengagement may not interfere with an otherwise secure mounting of example assembly 100 on steam dam 15. For example, exterior clamp roller 162 may be selectively disengaged or moveable upon encountering an obstacle 16 like a gusset protruding from a top flange of steam dam 15, such that assembly 100 may continue moving in a circumferential direction along steam dam 15 without separating from steam dam 15. Such movement may be permitted by a spring resistively pushing arm 110 and exterior roller 162 to clamp against steam dam 15, or selective disengagement may be achieved by rotating biasing arm 110 with a pneumatic cylinder 112 as shown in FIG. 2. For example, pneumatic cylinder 112 may rotate biasing arm 110 in direction 210 (FIG. 3) through actuation from a pneumatic line (not shown) run to assembly 100 or from a remotely controlled actuator. Such actuation of pneumatic cylinder 112 may cause expansion or contraction in direction 212 (FIG. 3), rotating exterior clamp roller 162 in direction 210 (FIG. 3) selectively against or away from steam dam 15. In the instance of contraction of pneumatic cylinder 112, exterior roller 162 may be rotated away from steam dam 15 and obstacle 16 thereon. Such movement may permit exterior roller 162 to pass over obstacle 16 when example assembly 100 is moving in an angular direction 215 (FIG. 3) along steam dam 15. In the instance of expansion of pneumatic cylinder 112, exterior roller 162 may be rotated toward steam dam 15 and movably secure assembly 100 thereto as discussed above. Example embodiment inspection assembly 100 may include a pair of arms 110 each with rollers 161 and 162 and pneumatic cylinder 112 joined to a single, rigid frame 155, as shown in FIGS. 2 and 3. Through the use of plural biasing arms 110 connecting to a shared frame 155, as long as one arm 110 remains clamped, with rollers 161 and 162 biased against steam dam 15, selective disengagement of any other biasing arm(s) 110 to permit roller relocation and potentially avoid obstacles is possible while keeping assembly 100 secured in a radial direction (direction 290 in FIG. 3) with steam dam 15. That is, rollers 162 may individually step over steam dam obstacles 16 or other objects without possibility of spurious movement of frame 155 in directions 290 or 210 (FIG. 3) due to other secured rollers. In this way, an operator may selectively disengage only those rollers approaching or abutting an obstacle 16 like a gusset, such as through individually contracting associated cylinders 112 through a pneumatic line or wireless actuator, for example, while maintaining at least one clamp roller pair 161/162 biased and secured to steam dam 15, thus overall maintaining frame 155 and example embodiment assembly 100 coupled with steam dam 15. While a pair of biasing arms 110 with selectively controllable pneumatic cylinders 112 are shown in the example of FIGS. 2 and 3 to control positioning and clamping of pairs of rollers 161 and 162, it is understood that other selectively movable structures, such as track and gears, magnets, ball clamps, spring-biased rollers, etc., may equally be used to both provide movement of example assembly 100 in radial direction 215 (FIG. 3) and maintain a constant radial position and orientation with regard to steam dam 15 while avoiding obstacles through selective, individual disengagement. As shown in FIG. 3, example embodiment inspection assembly 100 includes a handling rod 180 connecting to frame 155, which may be connected to an inspection arm 190 with a utility end 191. Inspection arm 190 may be moveable with respect to frame 155. For example, inspection arm may be extendible and retractable in a radial direction 290 by slidably engaging with a detent frame 159. Inspection arm 190 may include a utility end 191 shaped to secure to a tool, such as an inspection device including a camera or ultrasonic tester, for example. Utility end 191 is shown in FIG. 3 as an open-faced square jaw to secure a matching square end of a camera or other tool; however, any other shape or moveable clamping structure can be used for utility end 191, such as the examples of FIGS. 6B and 6C and FIG. 7. Multiple utility ends 191 may be used, such as one at each end of inspection arm 190, to perform operations both interior to and exterior to a steam dam or other mounting structure on both sides of assembly 100. Inspection arm 190 and/or utility end 191 may be further mobile in any dimension, such as vertically in direction 291, vertically about an axis in direction 291, or angularly about rod 180 in a direction 280, either alone/separately with regard to a remainder of assembly 100 or in combination therewith. In this way, an inspection device or other tool can be engaged in utility end 191 and moved to desired radial and vertical positions through movement of inspection arm 190 and/or utility end 191, while example embodiment assembly 100 otherwise remains at a fixed radial and vertical position on a steam dam or other structure. For example, an instrument attached to utility end 191 may be maneuvered around obstacles like steam separator hold down lugs on an exterior of steam dam 15 through radial and/or angular movement of inspection arm 190 as these obstacles are encountered by the instrument or any mast to which it is attached. Handling rod 180 may operate and/or move one or more different components of example embodiment inspection assembly 100. As shown in FIG. 3, handling rod 180 may include selection gear 185 that matches a gear track 198 of inspection arm 190. As handling rod 180 is rotated in direction 280, inspection arm 190 may be radially extended or retracted in direction 290 by selection gear 185 meshing with gear track 198 and driving inspection arm 190 in direction 290 as inspection arm 190 slides in detent frame 159. As shown in FIG. 2, inspection arm 190 may include one or more indentations 195 along its length that pass through detent frame 159, which may include a spring or other biased element that matches with one of the indentations 195 and resists further free extension or retraction of inspection arm 190. In this way, inspection arm 190 may be extended at known or desired intervals based on spacing of indentations 195 and resistance to further movement imparted by detent frame 195. As further shown in FIG. 3, lower selection gear 185 of handling rod 180 may further be positioned to mate with circumferential drive gear 186 in frame 155 of assembly 100. Handling rod 180 may further rotate circumferential drive gear 186 by rotating in direction 280. Handling rod 180 may discriminate between inspection arm 190 and drive gear 186 by moving laterally or vertically between the two, so as to contact only one of gear track 198 or teeth of gear 186 at any time with lower selection gear 185. Of course, closer selection gear 185 may also simultaneously drive inspection arm 190, gear 186, and/or any other structures. FIG. 4 is a detail illustration of a profile of example embodiment inspection assembly 100, showing some potential structures that are drivable with handling rod 180. As shown in FIG. 4, selection gear 185 of handling rod 180 may be vertically separated from gear track 198 and drive gear 186; that is, selection gear 185 may engage only one of drive gear 186 and gear track 198 depending on a vertical displacement. Spring 181 may bias selection gear 185 downward such that a default engagement is with driver gear 186 and an upward force must be imparted by an operator of rod 180 to move upward and engage gear track 198. A lower stem of pole 180 may be captured by frame 155 to permit limited vertical movement of lower selection gear 185 between drive gear 186 and gear track 198, shown by matching vertical arrows in FIG. 4. Circumferential drive gear 186 may power one or more interior clamp rollers 161 (FIG. 2), as discussed above in connection with FIG. 2. For example, as shown in FIG. 4, drive gear 186 may connect to one or more transmissions 187 between drive gear 186 and pivot points 165. Transmission 187 may be an extension that transfers rotation between drive gear 186 and roller 161 (FIG. 2) via pivot point 165, such as a gearbox or a chain or band that rotates with gear 186 and pivot point 165 to turn interior rollers 161. In this way, when handling pole 180 is engaged with drive gear 186 and rotated in direction 280 (FIG. 3), the force may be transmitted via transmission 187 to one or more interior rollers 161 biased against steam dam 15. In this way, example embodiment inspection assembly may be moved in circumferential direction 215 (FIG. 3) through rotation of handling pole 180. When handling rod 180 is raised against spring 181 so that lower selection gear 185 mated with gear track 198, similar rotation of handling rod 180 may instead move inspection arm 190. Handling rod 180 may extend several feet vertically, potentially all the way outside of any opened and flooded reactor, to human operators well above steam dam 15. Handling rod 180 may include a U-joint or flexible portion surrounded by spring 181 to permit some non-vertical or off-axis positioning while still transferring rotation to selection gear 185. Handling rod 180 may further include voids or floats to offset any weight of rod 180 or entire assembly 100, resulting in better vertical positioning of rod 180 under tension from such floats or cavities when submerged in reactor coolant. Odometers, rotation counters, electrical sensors, and the like are useable in connection with pole 180 to track and/or display an accurate position and/or number of turns of handling rod 180 in connection with gear 186 and/or inspection arm 190. In this way, a user may be able to accurately track a degree of circumferential movement of example assembly 100 and/or a degree of radial extension/retraction of inspection arm 190. Although example embodiment inspection assembly 100 is shown with a handling rod 180 driving various features of assembly 100, including circumferentially-driving rollers and an inspection arm, it is understood that any number of different power-providing devices and powered components are useable in assembly 100. For example, handling rod 180 may be powered to automatically rotate and raise/lower to interact with desired components by an operator handling the same from above; or handling rod 180 may drive other rollers, arms, and utility end movements in example embodiments. Or, for example, one or more remotely-operated motors may control movement and biasing of any or all of rollers 150, 161, and 162, inspection arm 190, and biasing arms 110. In this way, a remote user may still control movement of assembly in direction 215, actuation and release of rollers 161 and 162, and/or radial or vertical movement of inspection arm 190. Such motors may equally be paired with sensors that measure and report a degree of movement or force in any controlled element of assembly 100. Such sensors and controls may further power and control any inspection device, such as a camera or ultrasonic tester, paired with utility end 191. FIG. 7 is an illustration of another example embodiment inspection assembly 200, in use with an example embodiment vertical maneuvering assembly 300. Inspection assembly 200 may be substantially similar to example embodiment inspection assembly 100 (FIG. 2), except FIG. 5 may use different structures that are drivable with handling rod 180. As shown in FIG. 5, selection gear 185 of handling rod 180 may vertically move between circumferential drive gear 186, track gear 198, and vertical drive gear 298 and engage only one at a time depending on a vertical displacement. Spring 181 (FIG. 4) may still bias selection gear 185 downward. Further, a biased detent 251 may seat into detent grooves 252 in handling rod 180 to retain selection gear 185 of handling rod 180 at specific vertical positions of drive gear 186, track gear 198, or vertical drive gear 298. In this way, selection gear 185 may be locked, or retained until met with overcoming vertical force, at a meshed position for operation and movement in selected directions of example embodiment assembly 100. As shown in FIG. 5, drive gear 186 may connect by shaft 287 to clamp roller 161, such that rotation of drive gear 186 by selection gear 185 on rod 180 causes circumferential movement 215 along a steam dam or other structure by rotation of clamp roller 161. Further, instead of seating in a track, selection gear 185 may extend and retract inspection arm 190 via track gear 198. Selection gear 185 may also vertically move assembly 200 via vertical drive gear 298. Track gear 198 and drive gear 298 may connect through frame 155 to a track on arm 190 and/or a vertical surface of a mast or connection rod. Rotation of these gears is thus translated into radial movement of arm 190 or vertical movement of assembly 200, depending on which gear 198/298 is engaged. In this way, discreet vertical positioning of rod 180 may allow selection among three different types of movement in example embodiment inspection assembly 200, achieved by rotating rod 180 at the desired vertical level. Of course, motorization of any or all of gears 186, 198, and 298 is also possible to drive this movement without rod 180 providing energy to do so. FIGS. 6A, 6B, and 6C are illustrations of variations of utility end 191 shown in FIGS. 2 and 3 that are useable in example embodiment assemblies 100 or 200. For example, as shown in FIG. 6A, compressible clamp 192 may include two moveable jaws under constrictive force from cylinder 295 that may radially extend and or retract jaws of compressible clamp 192 to tighten and loosen the same. Or, for example, one jaw of clamp 192 may be stationary with cylinder 295 attached to a frame or base of assembly 100, such that extension or retraction of arm 190 loosens or tightens clamp 192. FIG. 6B illustrates a similar configuration, with an eyelet clamp 193 forming a quadrilateral opening with slightly rounded corners for gripping both round and angular-profiled tools under force from cylinder 295. FIG. 6C illustrates a multiple-eyelet clamp 194 that can hold multiple separate components in different eyelets when clamped. FIG. 7 is an illustration of another variation of utility end 191 with a vertical maneuvering assembly 300 on or mounted to inspection arm 190. While assembly 300 may be vertically supported by inspection arm 191, such as by interfacing with utility end 191, assembly 300 may still be rotatable and moveable relative to arm 190. As seen in FIG. 7, assembly 300 may hold a vertical mast 301 connected to an inspection device such as inspection camera 400. Of course, an ultrasonic tester, welding tool, reactor component, etc. may similarly be joined to vertical maneuvering assembly 300. Mast 301 may be vertically moveable in direction 291, and potentially rotatable in direction 381, by maneuvering assembly 300. Or, as shown in FIG. 7, camera 400 may be further mounted on a pivoting hinge to mast 301 for rotation in direction 381 as well as pan and tilt control. FIG. 8 is a detail illustration of vertical maneuvering assembly 300 inside any surrounding housing or guard shown in FIG. 7. As seen in FIG. 8, vertical maneuvering assembly 300 includes several rollers 310 that grip and vertically maneuver mast 301. Rollers 310 may be resilient, compressible, and/or higher-friction to encourage force transfer to mast 301, such as an abrasion-resistant urethane. For example, rollers 310 may have roughened or adhesive surfaces to increase grip on mast 301, and rollers 310 may have other shapes, such as a scooped or shaped rolling surface that matches and partially surrounds mast 301, either under compression or as a natural static shape when uncompressed. Rollers 310 may be repeated at various vertical heights, such as two or more vertically-separated banks of three as shown in FIG. 8. Three rollers 310 are at different positions about a perimeter of mast 301, such as at even 120-degree intervals. As shown in FIG. 9, rollers 310 may also be spaced at other angular intervals, such as a 90-degree pair separated 135 degrees from the other roller 310, to better capture quadrilateral edges as well as round surfaces of mast 301. Or, similarly, as shown in FIG. 10, four rollers 410 in another example embodiment vertical maneuvering assembly 300′ shown in relevant part may be positioned at even 90-degree intervals with engagement and release controlled by compression cylinders 421. As seen, any number and set of rollers in any angular configuration are useable in example embodiment assembly 300. One or more compression cylinders 321 may bias rollers 310 inward to forcefully seat against mast 301. Compression cylinder 321 may connect to axles of vertically-adjacent rollers 310 or to other structures of assembly 300 at offset positions. Expansion of compression cylinder 312 will thus torque or rotate rollers 310 toward mast 301 for additional compression. Similarly, retraction of compression cylinder 312 may release rollers 310 from mast 301, allowing free movement and removal of mast 301 from assembly 300. Compression cylinder 321 may be a pneumatic telescoping cylinder that is remotely actuated or locally expanded and compressed by a motor or manually tensioned by manipulating a release or set latch. Of course, any other actuator or tensioner may be used for compression cylinder 321 to bias rollers 310 in desired directions, including turnbuckles, springs, and other expanders. Vertical drive motor 322 may provide power or rotational force to one or more rollers 310 through a vertical drive transmission 316. For example, vertical drive motor 322 may include a gear that rotates when meshed with vertical drive transmission 316, which then rotates roller 310 through worm gear 317. Transmission 316 may connect to multiple rollers, such as upper and lower rollers 310 shown in FIG. 8 and move them in unison with proper gearing. For example, as shown in FIG. 9, transmission 316 may power multiple rollers 310 through plural worm gears 317. By rotating, rollers 310 may thus vertically move mast 301 up or down in direction 291 (FIG. 7) through assembly 300, achieving desired vertical displacement of a tool or device such as camera 400 with respect to a reactor component like a steam dam. Mast 301 may have any cross-sectional or perimeter shape, such as if mast 301 is a cable or rope with a round cross-section as shown in FIG. 9. Rotation of rollers 310 may act to vertically draw in or let out such rope or cable in direction 291 (FIG. 7) as mast 301. In the instance that mast 301 is stationary, assembly 300 may move itself vertically on mast 301 through rotation of rollers 310. Vertical drive motor 322 may be remotely actuated or locally controlled; of course, any other actuator or a connection from assembly 200 itself may be used to rotate rollers 310 and thus vertically position mast 301 in a desired direction. As shown in FIG. 7, example embodiment vertical maneuvering assembly 300 may also be moveable angularly and selectively in direction 381. For example, a planetary motor 320 may be mounted on a stationary a sun gear 315 (FIG. 8) to rotate rollers 301, mast 301 secured therein, compression cylinder 321, vertical drive motor 322, transmission 316, and worm gear 317 independent of inspection arm 190, to which sun gear 315 may be secured. Sun gear 315 may be annular with an empty central portion through which mast 301 may pass. Planetary motor 320 may include a planetary gear, worm gear, or other structure that meshes with sun gear 315 to spin the selected elements of assembly 300 and mast 301 as the planetary gear rotates under force from motor 320. Planetary motor 320 may be remotely actuated or locally controlled, and other actuators or connections may be used to rotate on sun gear 315 and thus angularly position mast 301 in a desired position. As shown in FIG. 7, example embodiment vertical maneuvering assembly 300 may be mounted on inspection arm 190 and supported by the same, but assembly 300 may vertically move and rotate mast 301 in directions 291 and 381 independent of inspection arm 190. For example, only a sun gear 315 may be rigidly secured to inspection arm 190, with the remainder of vertical movement assembly 300 being rotatable and mast 301 being further vertically movable relative to inspection arm 190. Motors 320 and 322 (FIG. 8) may move mast 301 and/or roller 310 independently of each other and inspection arm 190. FIG. 11 is an illustration of several different example embodiment inspection assemblies 100 on steam dam 15 in use with different configurations of vertical maneuvering assemblies 300. Example embodiment inspection assembly 100A may be similar to assembly 100 from FIGS. 2-4 selectively actuated with handling pole 180A, but with a double-ended inspection arm 190A having double eyelet clamp 194 from FIG. 6C. An instrument or tool 400A is clamped in one of the eyelets of the clamp that extends to an exterior of steam dam 15. Example embodiment inspection assembly 100B may be locally motorized, with no handling pole 180 for selective movement. A rigid vertical mast 301B extends directly from assembly 100B, on which example embodiment vertical maneuvering assembly 300B rides in a beanstalk fashion. By moving itself on mast 301B, assembly 300B also vertically moves a tool or instrument 400B extending therefrom in the vertical direction. Example embodiment inspection assembly 100C and vertical maneuvering assembly 300C may be similar to example embodiment vertical maneuvering assembly 300 from FIGS. 7-8, with assembly 100C driven by handling pole 180C. Mast 301B is suspended in example embodiment vertical maneuvering assembly 300C supported by an arm of assembly 100C. Example embodiment inspection assembly 100D has an opposite setup, with example embodiment vertical maneuvering assembly 300D extending outside of steam dam 15 and mast 301D extending upward to support tool 400D. Example embodiment inspection assembly 100E is motorized with no handling pole 180 and holds mast 103E in its arm. Example embodiment vertical maneuvering assembly 300E is mounted on mast 301E and traverses the same with an arm that supports instrument 400E. Example embodiment inspection assembly 100F is similarly motorized, with no handling pole or inspection arm but a central mast 301F extending directly from a frame or body of assembly 100F. Two example embodiment vertical maneuvering assemblies 300F and 300F′ are used, with 300F on mast 301F and 300F′ supported on an arm from 300F. Example embodiment vertical maneuvering assembly 300F′ supports a camera 400F on a separate rope or cable mast secured to an end of camera 400F, and assembly 300D adjusts pitch of camera 400F by vertically driving the mast. Separate assembly 300F controls absolute vertical positioning of assembly 300F′ and camera 400F as well as angular rotation of the same about mast 301F. Example embodiment inspection assemblies 100 and 200 and vertical maneuvering assembly 300 are configured to operate in a nuclear reactor environment submerged in reactor coolant. As such, assemblies 100, 200, and 300 may be fabricated entirely of materials that maintain their physical characteristics in a reactor and radioactive environment. For example, glasses, hard plastics like HDPE, nickel alloys like Inconel, stainless steels, and/or zirconium alloys may all be used for various components of assemblies 100, 200, and 300 without risk of significant degradation or contamination. Similarly, although example embodiment assemblies 100, 200, and 300 are illustrated with mechanical and pneumatic features, any electrical sensors, controls, or motors may be waterproofed an outfitted with appropriate electrical wired or wireless connections to permit submerged operation and control. Example embodiments and methods thus being described, it will be appreciated by one skilled in the art that example embodiments may be varied and substituted through routine experimentation while still falling within the scope of the following claims. For example, although the term “vertical” is used throughout this disclosure, it is understood that different orientations aside from strict up-and-down with respect to ground are useable for this dimension in example embodiments at different orientations. Or, for example, a variety of different structures aside from a steam dam atop a core shroud, as well as different sizes and configurations of steam dams, are compatible with and useable with example embodiments and methods simply through proper dimensioning of example embodiments—and fall within the scope of the claims. Such variations are not to be regarded as departure from the scope of these claims.
	description	This application is a divisional application of U.S. patent application Ser. No. 11/812,576, filed on Jun. 20, 2007 now U.S. Pat. No. 7,769,123 (published as U.S. Patent Application Publication No. 2008/0317192 A1 on Dec. 25, 2008), and claims the associated benefit under 35 U.S.C. §120 and 35 U.S.C. §121. The entire contents of parent U.S. patent application Ser. No. 11/812,576, entitled “INSPECTION, MAINTENANCE, AND REPAIR APPARATUSES AND METHODS FOR NUCLEAR REACTORS”, are incorporated herein by reference. 1. Field Example embodiments relate to inspection, maintenance, and repair apparatuses and methods for nuclear reactors. Additionally, example embodiments relate to inspection, maintenance, and repair apparatuses and methods for nuclear reactors in confined areas, such as within the downcomer annulus between the reactor pressure vessel and the core shroud. 2. Description of Related Art FIG. 1 is a sectional view, with parts cut away, of a typical reactor pressure vessel (“RPV”) 100 in a related art nuclear boiling water reactor (“BWR”). During operation of the BWR, coolant water circulating inside RPV 100 is heated by nuclear fission produced in core 102. Feedwater is admitted into RPV 100 via feedwater inlet 104 and feedwater sparger 106 (a ring-shaped pipe that includes apertures for circumferentially distributing the feedwater inside RPV 100). The feedwater from feedwater sparger 106 flows downwardly through downcomer annulus 108 (an annular region between RPV 100 and core shroud 110). Core shroud 110 is a stainless steel cylinder that surrounds core 102. Core 102 includes a multiplicity of fuel bundle assemblies 112 (two 2×2 arrays, for example, are shown in FIG. 1). Each array of fuel bundle assemblies 112 is supported at its top by top guide 114 and at its bottom by core plate 116. Top guide 114 provides lateral support for the top of fuel bundle assemblies 112 and maintains correct fuel-channel spacing to permit control rod insertion. The coolant water flows downward through downcomer annulus 108 and into core lower plenum 118. The coolant water in core lower plenum 118 in turn flows upward through core 102. The coolant water enters fuel bundle assemblies 112, wherein a boiling boundary layer is established. A mixture of water and steam exits core 102 and enters core upper plenum 120 under shroud head 122. Core upper plenum 120 provides standoff between the steam-water mixture exiting core 102 and entering standpipes 124. Standpipes 124 are disposed atop shroud head 122 and in fluid communication with core upper plenum 120. The steam-water mixture flows through standpipes 124 and enters steam separators 126 (which may be, for example, of the axial-flow, centrifugal type). Steam separators 126 substantially separate the steam-water mixture into liquid water and steam. The separated liquid water mixes with feedwater in mixing plenum 128. This mixture then returns to core 102 via downcomer annulus 108. The separated steam passes through steam dryers 130 and enters steam dome 132. The dried steam is withdrawn from RPV 100 via steam outlet 134 for use in turbines and other equipment (not shown). The BWR also includes a coolant recirculation system that provides the forced convection flow through core 102 necessary to attain the required power density. A portion of the water is sucked from the lower end of downcomer annulus 108 via recirculation water outlet 136 and forced by a centrifugal recirculation pump (not shown) into a plurality of jet pump assemblies 138 (only one of which is shown) via recirculation water inlets 140. The jet pump assemblies 138 are circumferentially distributed around the core shroud 110 and provide the required reactor core flow. A typical BWR includes 16 to 24 inlet mixers. As shown in FIG. 1, related art jet pump assemblies 138 typically include a pair of inlet mixers 142. Each inlet mixer 142 has an elbow 144 welded thereto which receives pressurized driving water from a recirculation pump (not shown) via inlet riser 146. An exemplary inlet mixer 142 includes a set of five nozzles circumferentially distributed at equal angles about the inlet mixer axis. Each nozzle is tapered radially inwardly at its outlet. The jet pump is energized by these convergent nozzles. Five secondary inlet openings are radially outside of the nozzle exits. Therefore, as jets of water exit the nozzles, water from downcomer annulus 108 is drawn into inlet mixer 142 via the secondary inlet openings, where it is mixed with coolant water from the recirculation pump. The coolant water then flows into diffuser 148. Core shroud 110 may include, for example, a shroud head flange (not shown) for supporting shroud head 122, an upper shroud wall (not shown) having a top end welded to the shroud head flange, a top guide support ring (not shown) welded to the bottom end of the upper shroud wall, a middle shroud wall (not shown) having a top end welded to the top guide support ring and including two or three vertically stacked shell sections (not shown) joined by mid-shroud attachment weld(s), and an annular core plate support ring (not shown) welded to the bottom end of the middle shroud wall and to the top end of a lower shroud wall (not shown). The entire shroud is supported by a shroud support (not shown), which is welded to the bottom of the lower shroud wall, and by an annular jet pump support plate (not shown), which is welded at its inner diameter to the shroud support and at its outer diameter to RPV 100. Typically, the material of core shroud 110 and associated welds is austenitic stainless steel having reduced carbon content. The heat-affected zones of the shroud girth welds, including the mid-shroud attachment weld(s), have residual weld stresses. Therefore, mechanisms are present for mid-shroud attachment weld(s) and other girth welds to be susceptible to intergranular stress corrosion cracking (IGSCC). IGSCC in the heat affected zone of any shroud girth seam weld diminishes the structural integrity of core shroud 110, which vertically and horizontally supports top guide 114 and shroud head 122. In particular, a cracked core shroud 110 increases the risks posed by a loss-of-coolant accident (LOCA) or seismic loads. During a LOCA, the loss of coolant from RPV 100 produces a loss of pressure above shroud head 122 and an increase in pressure inside core shroud 110, i.e., underneath shroud head 122. The result is an increased lifting force on shroud head 122 and on the upper portions of core shroud 110 to which shroud head 122 is bolted. If core shroud 110 has fully cracked girth welds, the lifting forces produced during a LOCA could cause core shroud 110 to separate along the areas of cracking, producing undesirable leaking of reactor coolant. Also, if the weld zones of core shroud 110 fail due to IGSCC, there is a risk of misalignment from seismic loads and damage to core 102 and the control rod components, which would adversely affect control rod insertion and safe shutdown. Thus, core shroud 110 needs to be examined periodically to determine its structural integrity and the need for repair. Ultrasonic inspection is a known technique for detecting cracks in nuclear reactor components. The inspection area of primary interest is the outside surface of core shroud 110 at the horizontal and/or vertical mid-shroud attachment weld(s). However, core shroud 110 is difficult to access. Installation access is limited to the annular space between the outside of core shroud 110 and the inside of RPV 100, between adjacent jet pump assemblies 138. Scanning operation access is additionally restricted within the narrow space between core shroud 110 and jet pump assemblies 138, which is about 0.5 inch wide in some locations. The inspection areas are highly radioactive and may be located under water, 50 feet or more below an operator's work platform. As a result, inspection of core shroud 110 and/or RPV 100, as well as all other inspection, maintenance, and repair within downcomer annulus 108 often is difficult and complicated. Solutions to the problem of inspecting core shroud 110 have been proposed, as discussed, for example, in U.S. Pat. No. 5,586,155 (“the '155 patent”). The disclosure of the '155 patent is incorporated in this application by reference. However, these proposed solutions do not include inspection, maintenance, and repair apparatuses and methods for nuclear reactors similar to the present invention. Example embodiments relate to inspection, maintenance, and repair apparatuses and methods for nuclear reactors. Additionally, example embodiments relate to inspection, maintenance, and repair apparatuses and methods for nuclear reactors in confined areas, such as within the downcomer annulus between the reactor pressure vessel and the core shroud. In an example embodiment, a method of inspecting a nuclear reactor may include: operatively connecting a fixing device, a first track, an arm, and an effector to form an inspection apparatus; inserting the inspection apparatus into the reactor; fixing the inspection apparatus within the reactor; and/or operating the inspection apparatus. The arm may have a contracted length. The arm may have an expanded length. The expanded length may be greater than two times the contracted length. In another example embodiment, a method of performing maintenance on a nuclear reactor may include: operatively connecting a fixing device, a first track, an arm, and one or more tools to form a maintenance apparatus; inserting the maintenance apparatus into the reactor; fixing the maintenance apparatus within the reactor; and/or operating the maintenance apparatus. The arm may have a contracted length. The arm may have an expanded length. The expanded length may be greater than two times the contracted length. In yet another example embodiment, a method of repairing a nuclear reactor may include: operatively connecting a fixing device, a first track, an arm, and one or more sensors, one or more tools, or one or more sensors and one or more tools to form a repair apparatus; inserting the repair apparatus into the reactor; fixing the repair apparatus within the reactor; and/or operating the repair apparatus. The arm may have a contracted length. The arm may have an expanded length. The expanded length may be greater than two times the contracted length. In still another example embodiment, an apparatus for inspecting a nuclear reactor may include: a first track; an arm; a fixing device; and/or an effector. The arm may be operatively connected to the first track. The fixing device may be operatively connected to the first track. The effector may be operatively connected to the arm. The arm may have a contracted length. The arm may have an expanded length. The expanded length may be greater than two times the contracted length. In a further example embodiment, an apparatus for inspecting a nuclear reactor may include: a first track; an arm; a fixing device; and/or an effector. The arm may be operatively connected to the first track. The fixing device may be operatively connected to the first track. The effector may be operatively connected to the arm. The first track may include one or more motors adapted to move the arm relative to the first track. In another further example embodiment, an apparatus for performing maintenance on a nuclear reactor may include: a first track; an arm; a fixing device; and/or one or more tools. The arm may be operatively connected to the first track. The fixing device may be operatively connected to the first track. The one or more tools may be operatively connected to the arm. The arm may have a contracted length. The arm may have an expanded length. The expanded length may be greater than two times the contracted length. In yet another further example embodiment, an apparatus for performing maintenance on a nuclear reactor, the apparatus comprising: a first track; an arm; a fixing device; and/or one or more tools. The arm may be operatively connected to the first track. The fixing device may be operatively connected to the first track. The one or more tools may be operatively connected to the arm. The first track may include one or more motors adapted to move the arm relative to the first track. In still another further example embodiment, an apparatus for repairing a nuclear reactor may include: a first track; an arm; a fixing device; one or more sensors; and/or one or more tools. The arm may be operatively connected to the first track. The fixing device may be operatively connected to the first track. The one or more sensors, the one or more tools, or the one or more sensors and the one or more tools may be operatively connected to the arm. The arm may have a contracted length. The arm may have an expanded length. The expanded length may be greater than two times the contracted length. In an additional example embodiment, an apparatus for repairing a nuclear reactor may include: a first track; an arm; a fixing device; one or more sensors; and/or one or more tools. The arm may be operatively connected to the first track. The fixing device may be operatively connected to the first track. The one or more sensors, the one or more tools, or the one or more sensors and the one or more tools may be operatively connected to the arm. The first track may include one or more motors adapted to move the arm relative to the first track. In another additional example embodiment, a kit for inspecting, performing maintenance on, or repairing a nuclear reactor may include: a first track; an arm; and/or a fixing device. The arm may be adapted to be operatively connected to the first track. The fixing device may be adapted to be operatively connected to the first track. The arm may have a contracted length. The arm may have an expanded length. The expanded length may be greater than two times the contracted length. In yet another additional example embodiment, a kit for inspecting, performing maintenance on, or repairing a nuclear reactor may include: a first track; an arm; and/or a fixing device. The arm may be adapted to be operatively connected to the first track. The fixing device may be adapted to be operatively connected to the first track. The first track may include one or more motors adapted to move the arm relative to the first track. Example embodiments will now be described more fully with reference to the accompanying drawings. Embodiments, however, may be embodied in many different forms and should not be construed as being limited to the example embodiments set forth herein. Rather, these example embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope to those skilled in the art. It will be understood that when a component is referred to as being “on,” “connected to,” “coupled to,” or “fixed to” another component, it may be directly on, connected to, coupled to, or fixed to the other component or intervening components may be present. In contrast, when a component is referred to as being “directly on,” “directly connected to,” “directly coupled to,” or “directly fixed to” another component, there are no intervening components present. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. It will be understood that although the terms first, second, third, etc., may be used herein to describe various elements, components, regions, layers, and/or sections, these elements, components, regions, layers, and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer, or section from another element, component, region, layer, or section. Thus, a first element, component, region, layer, or section discussed below could be termed a second element, component, region, layer, or section without departing from the teachings of the example embodiments. Spatially relative terms, such as “beneath,” “below,” “lower,” “above,” “upper,” and the like may be used herein for ease of description to describe one component and/or feature relative to another component and/or feature, or other component(s) and/or feature(s), as illustrated in the drawings. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes,” and/or “including,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, and/or components. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example embodiments belong. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and should not be interpreted in an idealized or overly formal sense unless expressly so defined herein. Reference will now be made to example embodiments, which are illustrated in the accompanying drawings, wherein like reference numerals refer to the like components throughout. FIG. 2 is a perspective view of an inspection, maintenance, and repair apparatus for nuclear reactors, according to an example embodiment. As shown in FIG. 2, apparatus 200 for inspection, maintenance, and/or repair of nuclear reactors may include: arm 202, first track 204, fixing device 206, and/or effector 208. Arm 202 may be operatively connected to first track 204. Fixing device 206 may be operatively connected to first track 204. Effector 208 may be operatively connected to arm 202. Apparatus 200 may allow a reduced number of movements for full or limited coverage of inspection, maintenance, and/or repair. At least partially as a result, apparatus 200 may shorten inspection cycles and/or simplify inspection plans. Arm 202 may have a contracted length and an expanded length. The expanded length may be greater than two times the contracted length. For example, the expanded length may be about 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, or more times the contracted length. In addition or in the alternative, first track 204 may include one or more motors adapted to move arm 202 relative to first track 204. Arm 202 may be adapted to move relative to first track 204. For example, arm 202 may be adapted to move along first track 204, to move relative to operative connection 210 of arm 202 to first track 204, and/or to rotate relative to first track 204. Effector 208 may include one or more sensors. For example, the one or more sensors may include at least one camera, at least one video camera, at least one transducer, at least one ultrasonic transducer, and/or at least one scanner. At least one of the one or more sensors may be, for example, sensitive to touch and/or pressure, moisture, temperature, pH, conductivity, and/or the presence and/or concentration of chemicals. In addition or in the alternative, effector 208 may include one or more tools, such as tools for cleaning the reactor, finding and/or retrieving reactor components, welding, and/or electrical discharge machining (“EDM”). In an example embodiment, apparatus 200 may be inserted into the reactor on the end of a long pole (not shown) connected to adapter assembly 212. The pole may be about 60 feet to about 80 feet in length, at least in part due to one or more of the distance from a workers' platform above the reactor to the reactor itself, the radiation exposure in the area of the workers' platform and the reactor, and the fact that the reactor may be substantially full of water when apparatus 200 is inserted into the reactor. One or more workers may control the pole to position the apparatus 200 as required in the reactor. That position might be, for example, between the outside of core shroud 110 and the inside of RPV 100, with first track 204, effector 208, and/or one or more of adjustable feet 214 substantially in contact with core shroud 110 and/or fixing device 206 substantially in contact with RPV 100. Apparatus 200 also may be inserted into the reactor using a remotely operated vehicle (“ROV”) (not shown), a cable/chain hoist (not shown), or similar device(s). When inserting apparatus 200 into the reactor, arm 202 may be rotated to be substantially parallel to first track 204. This parallelism may assist the one or more workers in expeditiously positioning apparatus 200 in the reactor. In an example embodiment, once apparatus 200 is properly positioned, the one or more workers may cause fixing device 206 to exert pressure on RPV 100 to force first track 204, effector 208, and/or one or more of adjustable feet 214 to contact core shroud 110, fixing apparatus 200 in position. Apparatus 200 also may be fixed in position by fixing device 206 in the form of a mast, scan arm, or equivalent that may be, for example, connected to core shroud 110 and/or the shroud head flange (not shown), or may ride on the steam dam (not shown) of the reactor. With apparatus 200 fixed in position, effector 208 may be positioned as required using arm 202 and first track 204. For example, assuming that first track 204 is fixed in a vertical orientation, arm 202 may be moved along first track 204 to raise or lower operative connection 210 (and, thus, to raise or lower effector 208), arm 202 may be moved relative to operative connection 210 (and, thus, to change the distance of effector 208 from operative connection 210), and/or arm 202 may be rotated relative to first track 204 to change the angle of arm 202 relative to first track 204 (and, thus, to change the angular position of effector 208). The narrow profile of arm 202 and effector 208 may allow effector 208 access to confined spaces inaccessible by other devices, such as ROVs. Effector 208 may be positioned by any of these “degrees of freedom” independently or by two or more simultaneously. Additionally or in the alternative, effector 208 may have “degrees of freedom” other than those discussed above. Some examples are in included in the discussion of arm 202 below. Apparatus 200 may further include a cable management system. The cable management system helps to manage one or more umbilical cables (not shown) that, for example, may supply power (i.e., electrical, pneumatic, and/or hydraulic (water-based)) to apparatus 200, may provide control signals to apparatus 200, and/or may provide the one or more workers with sensors signals from apparatus 200. The one or more umbilical cables may reach from a workers' platform to apparatus 200 and/or effector 208. First track 204 may include at least a portion of the cable management system. Similarly, arm 202 may include at least a portion of the cable management system. In an example embodiment, first track 204 may include a first portion of the cable management system and arm 202 may include a second portion of the cable management system. FIG. 3 is an exploded, perspective view of an arm of the apparatus of FIG. 2, while FIG. 4 is a reverse exploded, perspective view of the arm of FIG. 3. As shown in FIGS. 3 and 4, arm 202 may include second track 300; crossbar 302; guide block 304; guides 306 and/or 308; roller brackets 310, 312, and/or 314; rollers 316, 318, and/or 320; and/or effector bracket 322. Second track 300 may include three or more sections. Typically, because the sections are stacked, more sections results in a thicker second track 300. Sections of second track 300 may be manufactured with a standardized radius of curvature or standardized radii of curvature. However, the radius of curvature of second track 300 does not need to exactly match that of core shroud 110, RPV 100, etc. This may be true, for example, if effector 208 does not have to be in direct contact with core shroud 110, RPV 100, etc. In addition or in the alternative, this may be true because effector 208 may be operatively connected to arm 202 using effector bracket 322, and effector bracket 322 may be spring-loaded or equivalent to influence effector 208 toward core shroud 110, RPV 100, etc. In an example embodiment, crossbar 302 may function primarily as a structural support. In addition to the degrees of freedom discussed above, effector 208 may have additional degrees of freedom. For example, effector 208 may be operatively connected to arm 202 using a gimbal or some other device. In an example embodiment, effector 208 may be operatively connected to arm 202 anywhere on arm 202. As discussed above, arm 202 may include at least a portion of the cable management system. That portion may include, for example, one or more of guide block 304; guides 306 and/or 308; roller brackets 310, 312, and/or 314; and rollers 316, 318, and/or 320. FIG. 5 is a front perspective view of second track 300 of arm 202 of FIG. 3, FIG. 6 is a top view of second track 300 of FIG. 5, and FIG. 7 is a rear view of second track 300 of FIG. 6. FIG. 8 is a first detailed view of second track 300 of FIG. 7, FIG. 9 is a second detailed view of second track 300 of FIG. 7, and FIG. 10 is a third detailed view of second track 300 of FIG. 7. As shown in FIGS. 5-9, second track 300 may include first section 500, second section 502, third section 504, and/or fourth section 506. Fourth section 506 may be fixed to first track 204. First section 500 may include backbone 900, upper gear rack 902, upper rail 904, and/or lower rail 906. Second section 502 may include backbone 908, lower gear rack 910, one or more inner rollers 912, and/or one or more outer rollers 914. Third section 504 may include backbone 916, inner upper gear rack 918, outer upper gear rack 920, inner upper rail 922, inner lower rail 924, outer upper rail 926, and/or outer lower rail 928. Fourth section 506 may include backbone 930, lower gear rack 932, and/or one or more rollers (not shown). In FIG. 9, upper rail 904 and lower rail 906 of first section 500 are depicted as v-shaped rails. Although other shapes are possible, one or more inner rollers 912 of second section 502 ride on one or both of upper rail 904 and lower rail 906. Similarly, inner upper rail 922 and inner lower rail 924 of third section 504 are depicted as v-shaped rails. Although other shapes are possible, one or more outer rollers 914 of second section 502 ride on one or both of inner upper rail 922 and inner lower rail 924. In the same way, outer upper rail 926 and outer lower rail 928 of third section 504 are depicted as v-shaped rails. Although other shapes are possible, one or more rollers (not shown) of fourth section 506 ride on one or both of outer upper rail 926 and outer lower rail 928. Upper gear rack 902 and inner upper gear rack 918 may be connected by a first idler gear (not shown) so that when second track 300 is expanded or contracted by the driving of outer upper gear rack 920, first section 500 is driven by third section 504. Similarly, lower gear rack 910 and lower gear rack 932 may be connected by a second idler gear (not shown) so that when second track 300 is expanded or contracted by the driving of outer upper gear rack 920, second section 502 is driven by fourth section 506. In this way, when second track 300 is expanded or contracted by the driving of outer upper gear rack 920, first section 500, second section 502, and third section 504 may all move simultaneously relative to fourth section 506. In a first example embodiment, the extent of this simultaneous movement is proportional between sections. In a second example embodiment, the extent of the simultaneous movement is identical between sections. FIG. 8 shows rail adjuster 800 attached to first section 500. FIG. 10 shows rail adjuster 1000 attached to third section 504. Such rail adjusters allow mechanical adjustments to the tension between an upper and lower rail pair (i.e., between upper rail 904 and lower rail 906 of first section 500). In another example embodiment, apparatus 200 for inspection, maintenance, and/or repair of nuclear reactors may include: arm 202, first track 204, fixing device 206, and/or effector 208. Arm 202 may include a second track with a curvature opposite to that of second track 300. In this case, the apparatus 200 may be positioned, for example, between the outside of core shroud 110 and the inside of RPV 100, with first track 204, effector 208, and/or one or more of adjustable feet 214 substantially in contact with RPV 100 and/or fixing device 206 substantially in contact with core shroud 110. The apparatus 200 may be used, for example, to inspect the inner surface of RPV 100. In a further example embodiment, apparatus 200 for inspection, maintenance, and/or repair of nuclear reactors may include: arm 202, first track 204, fixing device 206, and/or effector 208. Arm 202 may include a second track that is substantially straight. In this case, the apparatus 200 may be used, for example, to inspect any substantially flat surface in the reactor. In yet another example embodiment, apparatus 200 for inspection, maintenance, and/or repair of nuclear reactors may include: arm 202, first track 204, fixing device 206, and/or effector 208. Arm 202 may include one or more second tracks. At least one of the one or more second tracks may be a curved track. In addition or in the alternative, at least one of the one or more second tracks may be a substantially straight track. In addition or in the alternative, at least one of the one or more second tracks may include at least three sections. In an example embodiment, the at least three sections may be are adapted to contract arm 202 to the contracted length and/or to expand arm 202 to the expanded length. FIG. 11 is an exploded, perspective view of first track 204 of apparatus 200 of FIG. 2, while FIG. 12 is a reverse exploded, perspective view of first track 204 of FIG. 11, FIG. 13 is a reverse exploded, perspective view of a first portion of first track 204 of FIG. 11, and FIG. 14 is a reverse exploded, perspective view of a second portion of first track 204 of FIG. 11. As shown in FIGS. 11-14, first track 204 may include first motor 1200, second motor 1202, and/or third motor 1204. First track 204 also may include first shaft 1206, second shaft 1208, and/or third shaft 1210. Additionally, first track 204 may include first rail 1212 and/or second rail 1214. Other components of first track 204 may include case 1216, motor box 1218, motor box cap 1220, top support plate 1222, top support side plate 1224, rotation block assembly 1226, cable guard 1228, cable guides 1230 and 1232, pulleys 1234 and 1236, dual pulley assembly 1238; and/or gear 1240. Gear 1240, associated with rotation block assembly 1226, may be best seen in FIGS. 3 and 11. Additionally, first track 204 may include extra components known to one of skill in the art (as shown in FIGS. 11-14), such as, for example, one or more ball bearings, brackets, cable guides, caps, drive gears, gaskets, idler gears, lock nuts, miter gears, pinions, screws, seals, shaft extensions, spacers, washers, and worm gears. In an example embodiment, first track 204 includes three gears—a pinion gear, an idler gear, and a worm gear—for each of first motor 1200, second motor 1202, and third motor 1204 (the motor turns the pinion gear, the pinion gear turns the idler gear, and the idler gear turns the worm gear). In a first example embodiment, first track 204 may include one or more motors (i.e., first motor 1200, second motor 1202, and/or third motor 1204) adapted to move arm 202 relative to first track 204. In a second example embodiment, first track 204 may include one or more motors adapted to move arm 202 along first track 204. In a third example embodiment, first track 204 may include one or more motors adapted to move arm 202 relative to operative connection 210. In a fourth example embodiment, first track 204 may include one or more motors adapted to rotate arm 202 relative to first track 204. In a fifth example embodiment, first track 204 may include first motor 1200, second motor 1202, and third motor 1204, wherein first motor 1200 is adapted to move arm 202 relative to operative connection 210, wherein second motor 1202 is adapted to move arm 202 along first track 204, and wherein third motor 1204 is adapted to rotate arm 202 relative to first track 204. As discussed above, first track 204 may include at least a portion of the cable management system. That portion may include, for example, one or more of cable guard 1228, cable guides 1230 and 1232, pulleys 1234 and 1236, and/or dual pulley assembly 1238, as well as some of the extra components known to one of skill in the art listed above. In an example embodiment, the umbilical cable of the cable management system passes between cable guide 1230 and pulley 1234, then passes between cable guide 1232 and pulley 1236, then passes through first track 204 to dual pulley assembly 1238, then under guide block 304 and around one or both of guides 306 and 308, and then to effector 208, optionally contacting one or more of rollers 316, 318, and 320. In a first example embodiment, tension is maintained on the umbilical cable that passes between cable guide 1230 and pulley 1234. In a second example embodiment, the tension is kept substantially constant. In a third example embodiment, the tension is kept substantially constant using a snatch-block arrangement. First motor 1200 and first shaft 1206 may drive arm 202 to move relative to operative connection 210. This movement may be to expand arm 202 (i.e., to unstack first section 500, second section 502, third section 504, and fourth section 506), or the movement may contract arm 202 (i.e., to stack first section 500, second section 502, third section 504, and fourth section 506). In an example embodiment, arm 202 may expand to either one side or the other of operative connection 210, providing additional flexibility in the use of apparatus 200. As discussed above, second track 300 may include three or more sections. For example, second track 300 may include three, four, five, six, seven, eight, or more sections. The number of sections may be odd or even. The number of sections that can be used is essentially a function of the strength of the materials used to construct second track 300, first rail 1212, and second rail 1214 (first rail 1212 and second rail 1214 support substantially the entire load of expanded second track 300 to effectively prevent this load from impacting the performance of first shaft 1206, second shaft 1208, and/or third shaft 1210 and, hence, the performance of first motor 1200, second motor 1202, and/or third motor 1204). Second motor 1202 and second shaft 1208 may drive arm 202 to move along first track 204. This “vertical” movement may be guided by first rail 1212 and/or second rail 1214. Third motor 1204 and third shaft 1210 may drive arm 202 to rotate relative to first track 204. The drive train also may include, for example, gear 1240. The rotation may be in either a clockwise or counterclockwise sense. Thus, arm 202 may be driven in rotation to any angular position relative to first track 204. As discussed above, when inserting apparatus 200 into the reactor (and also when removing apparatus 200 from the reactor), arm 202 may be rotated to be substantially parallel to first track 204. Arm 202 may be driven individually by first motor 1200/first shaft 1206, second motor 1202/second shaft 1208, or third motor 1204/third shaft 1210. In addition or in the alternative, arm 202 may be simultaneously driven by any combination of first motor 1200/first shaft 1206, second motor 1202/second shaft 1208, and/or third motor 1204/third shaft 1210. FIG. 15 is a perspective view of fixing device 206 of apparatus 200 of FIG. 2, while FIG. 16 is a reverse perspective view of fixing device 206 of FIG. 15. As shown in FIGS. 15 and 16, fixing device 206 may include base 1500, plurality of legs 1502, and/or one or more pneumatic or hydraulic pistons 1504. Advantageously, the fixing device 206 of FIGS. 15 and 16 may expand from a single driven point. The one or more pneumatic or hydraulic piston 1504 may be positioned, oriented, and/or connected to base 1500 and/or plurality of legs 1502 in a variety of configurations, as is known to one of ordinary skill in the art. In a first example embodiment, fixing device 206 may be a scissor jack. In a second example embodiment, fixing device 206 may include one or more scissor jacks. In a third example embodiment, fixing device 206 may include one or more hydraulic cylinders and/or one or more pneumatic cylinders. In a fourth example embodiment, fixing device 206 may include one or more hydraulic pistons and/or one or more pneumatic pistons. Typically, hydraulic systems in a reactor are water-based, and hydraulic and pneumatic systems must meet strict cleanliness and purity controls. In another first example embodiment, a method of inspecting a nuclear reactor may include: operatively connecting a fixing device, a first track, an arm, and an effector to form an inspection apparatus; inserting the inspection apparatus into the reactor; fixing the inspection apparatus within the reactor; and operating the inspection apparatus. In another second example embodiment, a method of operating a nuclear reactor may include: shutting down the nuclear reactor; inspecting the nuclear reactor, as discussed above; and starting up the nuclear reactor. In another third example embodiment, a method of performing maintenance on a nuclear reactor may include: operatively connecting a fixing device, a first track, an arm, and one or more tools to form a maintenance apparatus; inserting the maintenance apparatus into the reactor; fixing the maintenance apparatus within the reactor; and operating the maintenance apparatus. In another fourth example embodiment, a method of operating a nuclear reactor may include: shutting down the nuclear reactor; performing maintenance on the nuclear reactor, as discussed above; and starting up the nuclear reactor. In another fifth example embodiment, a method of repairing a nuclear reactor may include: operatively connecting a fixing device, a first track, an arm, and one or more sensors, one or more tools, or one or more sensors and one or more tools to form a repair apparatus; inserting the repair apparatus into the reactor; fixing the repair apparatus within the reactor; and operating the repair apparatus. In another sixth example embodiment, a method of operating a nuclear reactor may include: shutting down the nuclear reactor; repairing the nuclear reactor, as discussed above; and starting up the nuclear reactor. In each of these six example embodiments, the arm may have a contracted length and an expanded length, and the expanded length may be greater than two times the contracted length. While example embodiments have been particularly shown and described, it will be understood by those of ordinary skill in the art that various changes in form and details may be made in the example embodiments without departing from the spirit and scope of the present invention as defined by the following claims.
056339003	abstract	Iodine-125 is produced by neutron irradiation of .sup.124 Xe gas to form .sup.125 Xe and permitting decay of .sup.125 Xe to form .sup.125 I. Irradiation of the xenon-124 is effected in a first chamber within an enclosure and decay is effected in a second chamber within the enclosure and free from neutron flux. The apparatus is submersible in a nuclear reactor pool so as to absorb any radiation escaping the apparatus during the process. Xenon can be caused to move between the chambers remotely, underwater. The second chamber is removable from said enclosure and is transported to a suitable location to recover the .sup.125 I from its interior. Such recovery is effected by admitting an aqueous wash solution into the second chamber, whereupon it is heated, causing water from the wash solution to reflux and cleanse the interior surfaces of the second chamber, thus creating an aqueous solution of .sup.125 I, which then is caused to drain into a suitable container.
	summary
054988250	description	DESCRIPTION Referring to the drawings, wherein like reference numerals designate like parts in the several figures, and initially to FIG. 1, a toxic waste depot in accordance with the present invention is generally indicated at 10. The depot 10 is in the form of a building 11 that is located at least partly in the ground 12. The building 11 has an interior space 13 in which waste material 14 may be stored in a storage location 15. The storage location 15 preferably is located well below the surface 16 of the ground 12 in order to take advantage of the radiation shielding capability of the ground. Part of the storage location near ground level or above ground level may be used for toxic non-radioactive material, such as asbestos encased in STAYTEX.RTM. material. The building 11 also includes a fluid flow system generally designated 17 through which a fluid is conducted. The fluid is intended to provide both radiation shielding effect when necessary, and thermal energy removal, as is described in greater detail below. Also, the fluid provides for relatively easy removal and convenient storage of radiation-containing or radiation contaminated material therefrom. The toxic waste depot 10 includes a large hole or open pit opening 20 formed in the ground 12. Preferably adequate clearance and thickness of ground material, earth, etc. is located around the large hole 20 to provide adequate support for the building 11 and adequate shielding for radioactive energy. It has been found in the past that three feet of dirt often is adequate to provide satisfactory shielding of radiation. Additional thickness may be required in some circumstances; and possibly a thinner layer also may be adequate, depending on circumstances. There should be adequate support capability by the ground 12, including the base 21 of the large hole 20 to support the building 11. If necessary, additional footers (not shown) may be used to provide the desired support. Also, pipes 23 in the walls and roof of building 11 provide reinforcement to help make them structural. The large hole 20 is lined by a liner 22. An exemplary liner 22 may be of heavy duty plastic or rubber material used conventionally to line the bottom of convention toxic waste storage facilities. The liner 22 should have adequate strength to avoid tearing, and it should have adequate fluid impermeability characteristics to avoid leakage. An exemplary liner material is that sold by Reef Industries, Inc. of Houston, Tex. under the designation of PERMALON PLY X-210. Preferably the liner 22 extends side-wise beyond the building 11 a distance adequate to tend to prevent water from the directly flowing into the ground 12 directly adjacent the building 11. Such side-wise extensions 23, 24 protecting the ground areas 25, 26, respectively are seen in FIG. 1. Such extensions 23, 24 preferably fully circumscribe the building 11 for the described purpose, and by preventing water flow adjacent the sidewalls of the building 11, the tendency of the water to become radioactive and to leak into the water table and other water supplies is reduced. A catch basin and/or sump 26 may be provided outside the building 11 to collect material from an emergency spill; a pump may be provided to pump such collected material for further treatment, storage and/or disposal. The building 11 has a floor 30, sidewalls 31, and a roof 32. The top plan view of the building 11 may be circular, rectangular, hexagonal, or some other shape, depending on the shape of the large hole 20, the layout of the sidewalls 31, etc. The exposed above ground portion 31a of the sidewalls 31 and the roof 32 preferably are adequately thick to contain at least a portion of the fluid flow system 17. The below ground level portion 31b of the sidewalls 31 may be thinner than the portions 31a, as it may be unnecessary to have fluid flow system 17 therein or the extent of such fluid flow system therein may be less than is required in the portion 31a and roof 32. Specifically, since the fluid flow system 17 provides both radioactive energy shielding and thermal energy removing function, for the portion of the fluid flow system 17 that is not within the ground 12, a larger capacity of fluid is required. However, for that portion of the building 11 within the ground 12, radioactive energy shielding is provided at least in part by the ground itself, and, therefore, the extent of need for shielding provided by the fluid flow system 17 is reduced. However, it may be that some shielding is desired by the fluid flow system 17 in the below ground portion 31b of the sidewalls 31, and it also may be that thermal energy removal is desired in the portion 31b, too. The floor 30 is well below the surface 16 of the ground 12, and, therefore, shielding function of the fluid flow system 17 also may be unnecessary there. However, it may be desirable to have thermal energy removal function provided by the fluid flow system 17 in the floor 30. The building 11 preferably is several stories tall including about one story located above ground and several stories located below ground surface level, for example, at least three stories below ground. Each floor is made of structural prefabricated panels that are the right weight light weight compared to heavy concrete panels. The floor panels also include pipes in them to provide structural capability. The pipes are intended to carry the slurry described below to provide further shielding function. Since shielding is provided by the floors intermediate the bottom floor and the roof, the shielding function or burden required to be provided by the roof is reduced; and this reduces the thickness and other size and structure requirements of the roof. Such structure takes advantage of the shielding capacity of the ground 12 and also can take advantage of the support provided by the ground 12 reinforcing the sidewalls 31b located within the hole 20. The sidewalls 31 provide support for the roof 32. The sidewalls 31 and the floor 30 provide containment for the solid and liquid materials in the space 13 of the building 11. Furthermore, the sidewalls 31, floor 30 and roof 32 may include space to contain part of all of the fluid flow system 17. For example, a plurality of pipes may be located in the walls, floor and/or roof to conduct a slurry through the pipes for the described purpose of shielding and thermal energy removal. Pipes 23, also provide the structural integrity of the walls and roof. Concrete is too heavy for practical use for large structures (buildings) that are capable of reactivity shielding. Three feet or other relatively large thickness of concrete is needed to provide adequate shielding would be so heavy that it would be difficult at best, and in cases impossible, to provide adequately strong side walls and reinforcement in the roof to support such a concrete roof. The walls 31, floor 30, and roof 32 may be formed of various materials. Preferably, though, the walls, floor and roof are formed in part by a material sold under the U.S. Registered Trademark STAYTEX.RTM.. An example of such STAYTEX.RTM. materials and methods of using it are disclosed in U.S. Pat. No. 4,122,203. Additional description of such material and methods of using it are described in copending, commonly owned U.S. patent application Ser. No. 08/064,548, filed May 19, 1993, entitled Environmental Non-Toxic Encasement Systems for Coveting In-Place Asbestos and Lead Paint. The STAYTEX.RTM. material may provide both facing or surfacing functions as well as sealing functions. The STAYTEX.RTM. material may be sprayed onto joints between pre-fabricated panels making up the sidewalls 31, floor 30, or roof 32, for example, in the manner illustrated in FIG. 2. Briefly referring to FIG. 2, a plurality of pre-fabricated wall panels 33 are illustrated. The panels may be made of the following materials and/or by the following methods. An exemplary wall panel 33 is illustrated in FIGS. 3-7. The wall panel 33 includes pipes 23, for example of steel, polyvinyl chloride (pvc), or other metal, plastic material or other synthetic or natural material. A core material 34 of a panel is made of the mentioned STAYTEX.RTM. material 34a, preferably in combination with fiberglass sheets 34b. The STAYTEX.RTM. material can be molded or extruded relative to the pipes to form therewith an integral structure. The fiberglass may provide reinforcement and a base to which the STAYTEX.RTM. material easily can adhere. An exemplary manufacturing line 35 to manufacture the panels 33 is illustrated schematically in FIG. 8. To make a panel, the pipes 23 are connected in the manner desired for structural and fluid carrying purposes. The fiberglass sheets 34b are placed relative to pipes 23 on a conveyor 35a for carrying to a spray booth 35b and then to a mold 35c. The STAYTEX.RTM. material is applied to the pipes and fiberglass, e.g., in the spray booth 35b to make an integral structure thereof, particularly after the STAYTEX.RTM. material has cured to solid relatively rigid form. The STAYTEX.RTM. material may be applied by spraying, troweling, roller coating, etc. The panel may be heated at the infrared heater 35d to complete or to expedite curing. The panels may be shaped during molding by using a specifically shaped mold and/or molding press 35d to shape the panel during the formation of the panel. The pipes 23 may be arranged in a plurality of horizontal or vertical rows or in some other pattern in the panel 33. The pipes 23 may be connected for serial flow (see FIG. 4) of slurry through a panel; they may be connected for generally parallel flow (see FIG. 5) of slurry through a respective panel 33 or through plural panels (the latter case being where plural pipes of one panel are connected to plural pipes of another panel). One or more nipples 36 or other pipe connectors is exposed from each panel for connection to the flow system of the invention, i.e., to the pipes in another panel, to another portion of the flow system, etc. The wall panels, floor panels and roof panels may be identical. Where needed, additional facing or skin material to prevent damage to the panels and/or to provide particular characteristics to the panels may be used. Exemplary outer skin material include steel, brick, various natural and/or synthetic materials, composite materials, etc. In FIG. 6 is illustrated schematically a panel 33 with concrete facing material 33a, e.g., for contact with the earth of the large hole 20, and with brick facing material 33b, e.g., for exposure inside the building 11, say as the inside wall or top surface of a floor on which a vehicle easily may travel. In FIG. 7 is illustrated schematically a panel 33 with concrete facing material 33a, e.g., for contact with the earth of the large hole 20, and with steel facing material 33c, e.g., for exposure inside the building 11. At the seams 36 between adjacent panels 33 STAYTEX.RTM. material may be applied, for example, by spraying, troweling, roller coating, etc. to seal the joints. The STAYTEX.RTM. material also may be used to provide a sealing function between the sidewalls 31 and the floor 30 and/or roof 32 as well as between other portions of the overall structure of the building 11. Referring to the fluid flow system 17, a plurality of pipes 23 are located in the roof 32, in the sidewalls 31, including both the portions 31a, 31b, and in the floor(s). A liquid slurry 41 flows through the pipes 23, preferably being pumped therethrough by pumping equipment 42. The pumping equipment may include one or more standard water pumps, outside the building 11, either above ground, in ground, for example in a sump 42, and/or in a treatment system 43 located in the space 13 of the building 11 and/or outside the building. There may be one or more treatment systems and/or parts thereof, and each may be located inside or outside building 11. The sump 42 may be separate from, the same as, or a part of the sump or catch basin 26. A filter system 44 also is provided in the treatment system 43 to filter excessive radioactive material from the slurry 41, to filter other particular material from the slurry 41, and to provide such removed material to a storage container 46 for storage in the storage area 15. The slurry 41 in the pipes 23 preferably has a relatively high specific gravity compared to the specific gravity of water, which is 1. Exemplary relatively high specific gravity is from about 1.2 to about 1.6. Other relatively high specific gravities also may be used for the slurry 41. A specific gravity of 1.6 is obtainable by making a slurry of water and a relatively high concentration of epsom salt, as is elsewhere described herein. A slurry of water and boron also may be used. FIG. 9 is a graph showing the solubility of MgSO.sub.4 in H.sub.2 O and is taken from Gmelins, page 218, M. Polo, et al., and C. R. Acad. Sci., Ser C. 1971, 272 (7), 642. The lines in the graph of FIG. 9 have several alphabet letters thereon, and such lines between respective alphabet letters represent solid phases and transition points, as follows: AB: Ice PA1 B: -3.9.degree. C., 18% MgSO.sub.4 (Eutectic) PA1 BC: MgSO.sub.4.12H.sub.2 O PA1 C: 1.8.degree. C., 21.4% MgSO.sub.4 PA1 CD: MgSO.sub.4.7H.sub.2 O PA1 D: 48.3.degree. C., 33.1% MgSO.sub.4 PA1 DE: MgSO.sub.4.6H.sub.2 O (Gmelins) PA1 E: 67.5.degree. C., 36.1% MgSO.sub.4 PA1 EF: MgsO.sub.4.H.sub.2 O (Gmelins) PA1 DG: MgSO.sub.4.6H.sub.2 O (Polo et al.) PA1 G: 70.degree. C., 36.8% MgSO.sub.4 PA1 GH: MgSO.sub.4.4H.sub.2 O (Polo et al.) PA1 H: 78.degree. C., 38.8% MgSO.sub.4 PA1 HI: MgSO.sub.4.H.sub.2 O (Poloet al.) PA1 I: 130.degree. C., 44% MgSO.sub.4 PA1 IJ: Mg (OH).sub.2 Formation (Polo et al.) FIG. 10 is a graph showing the solubility of MgSO.sub.4 at elavated temperatures and is taken from Gmelins, page 222. The transition point at the junction of the several lines shown in the graph of FIG. 10 is at 67.5.degree. C., and 36.1% MgSO.sub.4. The graph of FIG. 11 presents the density of MgSO.sub.4 solutions. The solid lines in the graph are taken from Gmelins, page 243; and the dash lines in the graph are taken from Chem. Engineer's Handbook, Second Edition, page 418. A preferred exemplary material for use to raise the specific gravity of the slurry is epsom salt. In particular, it has been found that water containing up to about 30% epsom salt will have a specific gravity of about 1.2. Thirty percent is about the maximum amount of epsom salt that can be held in slurry in water without having to elevate the water temperature. However, higher concentration will be used by raising temperature of the slurry to try load the slurry with as much epsom salt as possible. See the graphs of FIGS. 9-11 for data regarding composition and characteristics of such slurries of water and epsom salt. For example, at a temperature of 36.degree. C. the specific gravity is about 1.35 for 30% MgSO.sub.4 by weight. As an example, the slurry is formed by mixing epsom salt with water and elevating the temperature of the mixture to increase the amount of epsom salt that can be dissolved in the water than that possible at usual room ambient temperature. The slurry also can contain solid particles of epsom salt. The percent of salts are regulated by the temperature of the slurry to maintain maximum salt levels-for most efficient operation. The radiation level is monitored by a conventional monitor 48 located in the treatment station 43 and/or elsewhere in the building 11 or even outside the building 11, for example, and by adjusting the temperature of the slurry proportionally to the radiation level, salt level can be increased or decreased as a function of radiation. Preferably such proportion is in direct proportion, although such direct proportion may be nonlinear. Such temperature control and salt level can be increased or decreased as a function of radiation. Such temperature control and salt level are adjusted by operation of the heat exchanger 45, for example, which is described hereinbelow. The use of 30% epsom salt in the water tends to reduce the freezing point of the water to about 0.degree. F. This feature advantageously helps to avoid the possibility of the slurry 41 freezing in the pipes 23. Continuous circulation of the fluid in the pipes under the influence of the pump 42 also helps to avoid freezing. Furthermore, thermal energy generated in the building 11 by the toxic waste stored therein also helps to avoid freezing of the solution. By using a slurry 41 that has a relatively high specific gravity, the shielding effectiveness of the slurry is enhanced. Therefore, the thickness of the roof 32 does not have to be a full three feet, which is the thickness necessary if water alone were used for radiation shielding purposes. It is noted that sodium chloride and other salts would not be particularly useful for the function provided by the epsom salt. Sodium chloride is corrosive and would tend to destroy the pipes 23 and/or other portions of the depot 10. Epsom salt, on the other hand, is not corrosive and is non-toxic. It is a purpose of the fluid flow system 17 to control the temperature in the space 13 of the building 11. For this purpose a heat exchanger 45 in the treatment center 43 receives fluid from the filter 44 and is able to cool the fluid and to transfer the thermal energy thereof to the environment external of the building 11. Heat from the heat exchanger is an energy source to use for other purposes, such as heating and cooling building 11, another building, or form some other purpose. The treatment center 43 may be located either inside or outside of the building 11; part may be in each location; or part or all of the treatment center may be redundantly located both inside and outside the building 11. An advantage to locating the heat exchanger or part of it outside the building is to use outside ambient temperature and/or supplemental heating or cooling provided there to control salt loading or salt level of the slurry. The shielding effectiveness of the slurry 41 in the pipes 23 of the fluid flow system 17 preferably is approximately equivalent to the shielding effectiveness of about three feet of water and/or approximately equivalent to about three inches of lead shielding. However, the weight of the lead shielding, the environmental hazard of the lead in general, the weight and containment requirements for three feet of water, and so on are not required in the present invention. Rather, the pipes 23 may be included within the roof 32 and the exposed above ground sidewalls 31a. Pipes 23 of the fluid flow system 17 also may be included in the below ground portions 31b of the sidewalls and/or in the floor 30. Further, the pipes 23 may be used to conduct slurry 41 in other places in the building 11 for the purpose of generally controlling the temperature in the building. The thickness of the below ground portions 31b of the sidewalls and the thickness of the floor 30 need not be as great as the thickness of the roof 32 or of the above ground portion 31a of the sidewalls, since the ground 12 can be relied on to provide shielding function, as was described above. In operation of the toxic waste depot 10, then, waste, such as toxic waste in general, radioactive waste in particular, etc. may be stored in the building. The pump 42 pumps slurry 41 through the pipes 23 of the fluid flow system 17. The slurry tends to prevent leakage of radiation through the roof 32 and above ground portion 31a of the sidewalls. The epsom salt in the slurry tends to absorb radiation. The ground 12 tends to prevent leakage of radiation to the above ground external environment or to the external environment more than several feet away from the building 11. The slurry 41 tends to remove thermal energy (heat) from the interior space 13 of the building in order to control the temperature therein. The excess heat can be conducted by the heat exchanger 45 to the environment external of the building 11 or to some other location without contaminating the external environment. The filter 44 may be used to remove radioactive material, e.g., the epsom salt or equivalent and/or similar functioning material, from the slurry 41 and/or particulates from the slurry 41 as waste. Such waste may be placed in drums or otherwise delivered to the storage area 15 in the space 13 of the building 11. In the filter 44 of the treatment plant 43 the slurry is cooled to cause the contaminated salt particles to drop out. The contaminated solid particles can be filtered from the slurry and then can be processed for detoxification and/or they can be stored. For such storage, for example, a settling pit 49 can be used to store the particles. Such a settling pit 49 is depicted schematically in FIG. 1. The settling pit may have at least three feet deep of water as a shield for blocking upward emission of radiation. The slurry can be pumped into the settling pit 49, and the settling pit can serve a filtering function in addition to or alternatively to the filter 44. The slurry will remain below the water level due to the larger specific gravity of the slurry. The contaminated salt particles will precipitate out to the bottom of the pit by maintaining the temperature of the pit relatively cool, e.g., sufficiently cool to effect such precipitating function. The remaining slurry which is substantially uncontaminated can be removed from the settling pit; subsequently loaded as much as possible with epsom salt; and pumped through the flow system 17 again. A door 50 provides an access to the interior space 13 of the building 11. The door 50 may be made of the same type of material of which the above ground portion 31a of the side walls is made and preferably the door also includes a portion of the fluid flow system 17 to provide for radiation shielding and for temperature control functions. The height of the door 50 preferably is adequate to provide, when open, access to a forklift vehicle or other vehicle that is used to carry into the space 13 fifty-five gallon drums 46 of toxic waste or some other size containers for storage within the space 13 of the building 11. A top plan view of the door 50 is shown in FIG. 12. The door 50 preferably includes one or a plurality of baffle walls which provide a circuitous route into the interior 13 of the building 11 while preventing a direct path for radiation leakage through the door. As is seen in FIG. 12, the door includes an outer door 50a in the outer wall 50b, which is comprised of panels 33, for example. The outer door 50a can be opened for access-to the building interior 13 or closed. A baffle wall 50c blocks a direct path into the building interior from the door 50a. The interior wall 50d has an opening 50e which provides direct entrance to the interior 13. The space 50f between the walls 50b, 50c, 50d is a circuitous path between the outside ambient environment and the interior of the building. The size of the space 50f preferably is adequate for a vehicle to drive therealong in order to carry waste, containers, or equipment into or from the building. Each of the walls 50b, 50c, 50d is made of a plurality of the panels 33. An elevator 51 includes an elevator shaft 52 and an elevator car 53 for transporting the forklift truck and/or the waste as well as individuals between various levels in the building 11. Also, a ramp 54 is provided to enable the forklift truck and/or individuals to drive or to walk between levels of the building 11. A floor 55 part way across the building or across the entire building is provided for various storage, equipment, and/or other functions as may be desired. Racks 47 for storing drums 46 or other material may be provided on one or more floors. The racks also may be used to store encased asbestos, lead painted objects, or other material. In using the toxic waste depot 10 to store radioactive material, the radioactive material preferably is stored at the lowest levels of the building. The radiation tends to emit horizontally and perpendicularly in straight lines through the walls into the ground. The ground is a good shield and prevents the radiation from reaching other sources of water, etc. The fluid system 17 also may reduce such radiation that is emitted into the ground, depending on the extend to which slurry 41 is located in the side walls which are below ground. That radiation which tends to emit vertically is finally blocked by the slurry 41 flowing through the pipes 23 in the fluid flow system in the roof 32. Temperature in the space 13 of the building 11 is controlled by the fluid flow system and the heat exchanger 45 associated therewith so that the possibility of dangerous conditions due to high temperature in the building is avoided. The radiation blocking and/or absorbing function of the floors of the building 11, especially the ones intermediate the bottom floor and the roof, also reduce the radiation blocking and/or shielding requirement of the roof 32. This allows the roof to have a practical thickness that will be both efficient and economical. That is, the roof can be of reduced thickness, mass, etc., compared to the requirements for roofs in prior primarily concrete storage facilities. The building 11 provides a storage facility for nuclear and other toxic waste. The waste may be stored in drums 46. The waste and/or drums 46 may be stored in racks 47, if desired. Contaminated equipment from a dismantled nuclear plant or from a refurbished nuclear plant also may be stored in the building 11 either in a drum, on a rack, or placed on the floor of the building. Since the bottom floor 30 has maximum direct support, e.g., from the earth beneath, it is desirable to place heavier material on the bottom floor and to place less heavy material on the upper floor level(s) 55. Additionally, as was mentioned above, the building 11 provides a place for storage of asbestos, objects painted with lead painted and/or other types of materials which have been encased in STAYTEX.RTM. material according to the disclosure of U.S. patent application Ser. No. 08/064,548. However, alternatively such encased materials can be placed directly in a conventional land fill. The building 11 of the present invention preferably is of a modular design in that multiple panels can be used to form walls, floor and ceiling thereof. Preferably the building 11 is provided with gravity ventilation and with anti-corrosive coatings, where needed. Desirably the height between floor and ceiling permits double stacking of drums or other storage containers. Seismic fie-downs may be provided for securing the building in the event of a tremor. Concrete underground structures are suspect; they may crack. The building of the present invention using panels 33 in walls, floors and ceiling/roof is more flexible than concrete and is less subject to damage due to earth tremors than conventional concrete structures. Other features includable in the building 11 of the invention include a fire suppression system. Desirably the various fixtures are explosion proof, such as the mechanical equipment, ventilation equipment, lighting, and HVAC system. The various parts of the building may be non-combustible having a fire rating of 1 to 4 hours. Sprinkler systems and monitoring systems for fire, gas, etc. may be provided. Exemplary toxic gas monitoring products are sold by Kern Medical Products Corp. The sumps described preferably are segregated for security and backup; and walls may be provided in the building to separate various portions. The building may be temperature controlled using appropriate HVAC equipment, and may take advantage of the heat exchanger 45 and flow system 17 of the invention, if desired. Further, if desired FM explosion relief panels may be used in the building. It will be appreciated that in the present invention an improved building structure provides a storage depot for plutonium and nuclear waste, for example. A fluid circulation system may provide temperature control for the storage depot and also blocks transmission and absorbs nuclear radiation. Such nuclear radiation absorption may be in epsom salt which is loaded into the fluid to form a slurry. The epsom salt may be removed from the slurry and subsequently stored in the building. The fluid can be re-loaded with epsom salt for further circulation in the depot to block and to absorb additional radiation.
	abstract	An apparatus for providing a signal indicative of a property of an earth formation includes: a carrier conveyable through a borehole; a neutron source disposed on the carrier and configured to emit neutrons into the earth formation; a radiation detector disposed on the carrier and configured to detect radiation from the earth formation due to interaction of emitted neutrons with the earth formation and to provide the signal indicative of the property; and a neutron shield configured to shield the radiation detector from emitted neutrons that did not interact with the earth formation; wherein the radiation detector shield includes a glass ceramic material having a plurality of nano-crystallites, each nano-crystallite in the plurality having a periodic crystal structure with a diameter or dimension that is less than 1000 nm that includes Li and/or Boron and a rare-earth element that have positions in the periodic crystal structure of each nano-crystallite.
052672891	summary	BACKGROUND OF THE INVENTION The present invention relate to the surface treatment of nuclear fuel assembly components such as fuel rod cladding and control rod guide tubes. U.S. Pat. No. 4,724,016 (Anthony) discloses the use of ion implantation, particularly N, to enhance the wear and/or corrosion resistance of a zirconium alloy fuel rod cladding. The implantation process should be carried out without depositing a superstrate, i.e., plating surface, that dimensionally alters the component. Ion implantation has traditionally been performed by the use of an implanter system consisting of an ion source, ion accelerator, mass separation system, and target chamber. Conrad and Forest have developed an alternate process called plasma source ion implantation (PSII) that is useful for semiconductor processing and surface modification of materials. J. R. Conrad et al, IEEE International Conference on Plasma Science, Saskatoon, Canada, May 19-21, 1986. PSII involves immersing the object to be implanted into a steady-state gaseous plasma and repetitively pulse biasing the object to a high negative voltage, thereby accelerating the ions across the sheath and implanting them into the target. PSII is unsuitable for the plating-free implantation of metal ions due to the collection of low-energy ions, and therefore plating of the substrate between bias pulses. Godechot and Yu developed a surface-modification technique in which metal ion guns were used for simultaneous low-energy ion deposition and high-energy ion implantation. I. G. Brown et al, Applied Physics Letters 58, 1392 (1991). The process described by them is designed to avoid the possibility of plating since the plasma pulse contains no neutral atoms or macroparticles and the substrate is always biased so that there is no low-energy streaming plasma; therefore, the size and geometry of the substance is preserved. Utilizing this process, silicon wafers have been implanted with aluminium ions at doses of up to 3.times.10.sup.14 /cm.sup.2, but the process is energy intensive. Chan, Meassick and Sroda have recently reported the use of a cathodic arc with electromagnetic dust filter as a source of highly energetic metal ions. The ions are then used for plating-free metal-ion implantation. C. Chan et al, "Plating-free Metal Ion Implantation Utilizing the Cathodic Vacuum Arc As An Ion Source", Appl. Phy. Lett., Vol. 60., No. 2 (March 1992). SUMMARY OF THE INVENTION It is, accordingly, an object of the present invention to provide an improved system and method for the implantation of metal ions onto nuclear fuel assembly components such as fuel rods, without plating. This object is achieved by utilizing a cathodic vacuum arc as a cost-effective source of high energy ions that can penetrate the component substrate to greater depth than conventional ion implantation techniques, without the deposition of a surface coating. Depths of approximately 0.2 .mu.m are achievable with nitride implantation species, with energy reduction of at least an order of a magnitude (depending on the implant species) relative to conventional techniques such as those of the Anthony patent, Conrad et al, and Godechot et al.
055679528	summary	FIELD OF THE INVENTION The invention concerns a fixing means for the base of a transport and/or storage container for highly radioactive material, in particular for irradiated nuclear fuel assemblies or their highly active reprocessing waste. DESCRIPTION OF RELATED ART Containers for highly radioactive material generally comprise a thick shielded chamber which confines the material, stops gamma radiation and is mechanically strong, even under accidental severe Conditions. They are generally cylindrical with a cross section which is either completely circular or is provided with flats. They comprise a tube which is closed at one end by a base which is permanently fixed thereto. The other end constitutes the main opening which is closed by a removable plug or cover which is often complex, for filling and emptying the contents. These closures must remain sealed (sometimes even to helium) when under accidental severe conditions, in particular after regulation drop tests, for example a drop of 9 m along a tube generatrix, on a corner of the container, on the base or on the cover, including penetration drops. The main frame of the tube and closures can be formed of a thick metal wall of high mechanical strength, for example a steel, which can be several tens of centimeters thick; thus containers for transport and/or storage of nuclear fuel assemblies or vitrified waste, the steel tube can be more than 25 or 30 cm thick, similarly the base and the main cover, and the unladen weight of the container assembly can be up to 120 t; its laden weight can be 150 t or more. The radiological shielding provided by the frame can be supplemented by layers of appropriate materials outside or inside the container, on the tube or on the end closures. A known container type is illustrated in FIG. 1, which shows: thick tube (1), for example of steel, covered with further layers (2), (3) of radiation absorbing material. The main closure system comprises two covers, a primary cover (4) and a secondary protective cover (5), both removable. Particular fixing or monitoring apparatus are not shown; PA1 a non removable base (6) which in this case is fixed to tube (1) by a weld (7) through the entire thickness of the tube; PA1 handling lugs (8) which are generally welded across weld (7). A weld of type (7) is long and difficult to make because of the great thickness of the steel which must be welded; great care is necessary and many checks must be carried out during manufacture because the weld alone holds the base in position and provides the drop strength as well as sealing the container. This welding problem has been simplified by providing a further closure means as illustrated in FIG. 2. Base (6) has an external diameter which is equal to that of tube (1); it includes a Shoulder (9) at the periphery of the internal surface (19), which cooperates with the internal diameter of tube (1) and allows base (6) to be cold assembled with a light friction fit, fitted partially inside the tube and abutting the cross sectional surface of end (10) of tube (1). A peripheral weld seam, which is simpler to make and check than the weld described above, holds base (6) in place. It can be completed by a second weld seam (18) on the inner face. In this type of assembly, here again a weld ensures that base (6) is held in place and seals the tube; the welds are extremely stressed if the container is accidentally dropped along a tube generatrix or at an angle to the base. As before, then, they must be made with extreme care and closely checked. They constitute a weak point there is a risk of rupture which cannot guarantee a complete seal in the event of a severe shock. European patent EP-A-0 061 400 describes a closure means for a container for radioactive material in which the seal is provided solely by Shrink fitting the (removable) cover into a tube (p.2, 1.37-38 to p.3, 1.30) which is brought about by an absence of faults in the contacting surfaces (p.4, 1.5-6). It also describes a boss (7) located On the tube on either side of the sealing surfaces, which is not in permanent contact with the removable cover and whose size is linked to the expansion of the tube. This thus creates an obstacle which cannot resist axial displacement of the cover (p.3, 1.31-32, 35-36, 39). French patent FR-A-2 092 502 describes a vacuum seal which is obtained by shrink fitting, one of the shrink fitted pieces being provided with an edge which deforms on contraction. European patent EP-A 0 101 362 describes a sealed closure for a removable cover produced by shrink fitting two conical portions, for a container for the transport of radioactive material; the contacting surfaces must be made with care (p.2, 1.9-10); the closure comprises an axial abutment and the cover projects beyond the tube. These various assemblies cannot guarantee a seal in the event of a severe shock. SUMMARY OF THE INVENTION We have sought to overcome these problems and develop a means for assembling a base which is more secure and which avoids weak points with their associated rupture risks or affect the seal of the container in the event of the container being dropped, in particular horizontal or oblique drops, which are usually more severe, but also vertical drops, on the base or on the cover, including penetration drops. We have also developed a simple assembly which is economical to manufacture. The invention therefore concerns a means for fixing the base of a shielded container for transport and/or storage of highly radioactive material, comprising a tube and a non removable base of thick metal, for example steel, the tube and base having respectively, at least over a certain height, an internal wall and a lateral wall forming a right cylinder with a circular cross section in contact with each other, the base being held in place by shrink fitting its lateral wall with the portion of the internal wall of the tube in contact therewith, characterised in that the base is located at least partially inside the tube, in that said portion of the internal wall of the tube comprises a shoulder which cooperates with a corresponding opposed shoulder in the lateral wall of the base and in that the base is connected to the tube by a continuous weld seam on its external surface and by a further weld seam on its internal surface. The base-tube closure is permanent. The means of the invention ensures that the base will not displace relative to the tube, due to the shrink fitting in the event of a horizontal drop, due to the opposed shoulder in the event of a vertical drop on the base, and due to the combination of these two elements in the event of an oblique drop on the base. Thus, the weld seams which provide a perfect seal to helium only suffer weak stresses, for example due to the contents of the container rebounding in the event of a vertical drop on the cover. The welds can thus be smaller. In general, a first weld seam connects the peripheral edge of the external surface of the base to the internal edge of the end face of the tube or the internal surface of the tube, the recessed base thus providing a volume which can usefully accommodate, for example, an additional incompressible neutron shield. Similarly, a second weld seam connects the peripheral edge of the inner surface of the base to the inner wall of the tube. These weld seams seal the container, in particular to confine radioactive material in the container cavity or to avoid contamination when immersed in a cooling pond. They are not highly stressed mechanically in the event of a drop, even in the event of a vertical or an oblique drop on a lower edge of the container, or event in the event of the load rebounding against the base in the event of a drop on the cover. Thus the means of the invention not only significantly reduces the volume (up to -95%) and size of the welds, but also the specifications for these welds are less demanding. In particular, checks are simplified compared with those carried out of prior art welds, which latter play a major mechanical role in holding the base on the tube. This facilitates manufacture and provides cost advantages. Shrink fitting ensures the absence base and the tube, by preventing any relative movement between these two pieces during a drop, thus maintaining the integrity of the welds. To obtain this result, the facing surfaces during shrink fitting do not have to be as carefully prepared as would be necessary if the shrink fitting had to provide the seal for the container. It should be noted that, in the means of the invention, the weld seams can also prevent the onset of corrosion at the base--tube interface, which corrosion can occur when the container is immersed in a cooling pond or as a result of condensation from the atmosphere and which would damage the base--tube joint; they can also prevent contamination from entering this interface. The shoulder in the inner surface of the tube is in intimate contact with the corresponding opposed shoulder in the lateral wall of the base; it reduces stresses in the welds, primarily in the event of a vertical penetration drop in the centre of the base. It also ensures exact location of the base with respect to the tube. Shrink fitting is generally carried out on the small and the large diameter to produce double shrink fit. It can also be effected solely on the small diameter (towards the container cavity); in both cases, the height of the opposed shoulder of the base resting on the shoulder of the tube can be adjusted so that its transverse strength is sufficient. Advantageously, the forged base is located substantially inside the tube, the external surface of said forged base or that of the optional complementary neutron shielding being flush with the end of the tube; this disposition distributes the shock over the base and tube in the event of a vertical drop. Shrink fitting is effected by ensuring that the lateral wall of the base has a diameter which is slightly greater than that of the corresponding internal wall of the tube. The base is fitted into the tube after the two components have been heated to temperatures which are sufficiently different to provide a suitable temporary allowance for assembly. After fitting, the external surface of the base advantageously does not go beyond the plane containing the end face of the tube, the base thus being located entirely within the tube. After cooling, the shrink fitting force develops over the whole of the lateral wall of the base, or over only a portion of its thickness, and is sufficient to hold it in place. The shrink fitting is the stronger the larger the difference, when cold, between the diameter of the lateral wall of the base and that of the corresponding internal wall of the tube recommended, however, that this difference is kept below a limiting value above which the tensional strains in the tube and/or compressional strains in the base would go beyond the accepted threshold for the material used. With the means of the invention, the shrink fitting force can be regulated by adjusting the value of the excess of the external diameter of the base when cold over the internal diameter of the corresponding internal wall of the tube, also when cold. By way of example, when the base and tube are of steel and for a difference between their diameters of between 0-5 and 1 per thousand (which would necessitate a temperature difference of the order of 200K during assembly), the shrink fitting force at the interface can be of the order of 100 MPa, which is an acceptable value for most types of steel. When the cavity of the container has a non circular cross section, in general the internal wall of the tube which contacts the base is machined to produce a circular cross section which cooperates with the circular lateral wall of the base during shrank fitting A wide variety of thick metals can be selected to form the tube and the base. The choice can be guided by mechanical properties, corrosion resistance, protection against radiation. etc. . . If required, different metals could be used for the base and tube- Preferably, the metal is selected from steels (optionally stainless) copper and its alloys, for example bronzes, etc. . . Advantageously, the tube comprises handling lugs fixed on the external wall close to the base and the cover. With the fixing mode of the invention, the lugs near the base are fixed directly to the tube, for example by welding, and the weld does not interfere with other welds, unlike those of the prior art (see, for example, FIGS. 1 and 2). Welds which cross over One another generally run the risk of mutual embrittlement, and thus the absence of weld interference is an additional advantage of the invention. The means of the invention, comprising a base which is held in place by shrink fitting, is particularly suitable for fixing the base of containers for highly radioactive material with very thick walls (base and tube) of metal, for example steel, typically 10 cm to 50 cm thick (generally 20 to 30 cm thick) and weighing more that 10 t (generally 70 to 150 t), Cooperation of the means employed in the invention also means that containers can be produced which are simple and thus economical to make, which satisfy specifications for transport and/or storage containers, including those for liquids, and in particular satisfy the requirements imposed by international regulations governing drop conditions or accidental severe shocks (including horizontal drops along a tube generatrix or obliquely at an angle to the tube near the base), while at the same time reducing the checks required during manufacture. The stresses occurring during a severe impact do not directly affect the weld seams of the base--tube interface. Thus with the means of the invention, the forces which occur during severe shocks or drops do not damage the base--tube joint, thus improving not only the seal security but also corrosion protection and contamination protection of said base--tube interface. In addition, a simpler method of manufacture is employed which uses only known machining or welding techniques.
	abstract	A method for automatically cutting off power in case of a low battery voltage in a mobile electronic unit is provided. The method comprises (a) cutting off the power of the mobile electronic unit when a battery voltage is detected in a first check section during a booting period of the mobile electronic unit that is not in a normal state, and (b) cutting off the power of the mobile electronic unit when the battery voltage detected with respect to the first check section is in the normal state and when a battery voltage is detected in a second check section during a period after booting of the mobile electronic unit is completed that is not in the normal state.
052788822	abstract	A stabilized alpha metal matrix provides an improved ductility, creep strength, and corrosion resistance against irradiation in a zirconium alloy containing on a weight percentage basis tin in a range of 0.4 to 1.0 percent and typically 0.5; iron in a range of 0.3 to 0.6 percent, and typically 0.46 percent; chromium in a range of 0.2 to 0.4 percent, and typically 0.23 percent; silicon in a range of 50 to 200 ppm, and typically 100 ppm; and oxygen in a range 1200 to 2500 ppm, typically 1800 to 2200 ppm. The high oxygen level assists in reducing hydrogen uptake of the alloy compared to Zircaloy-4, for example.
	summary
	abstract	A system and method for molecular breast imaging (MBI) using pixelated gamma cameras provide easier patient positioning and biopsy access using compression paddles and movable gamma cameras. The paddles and cameras can be curved to better conform to the breast shape. A variable angle slant-hole collimator is provided to assist in stereotactic imaging for biopsy guidance. Methods for performing an MBI screening or diagnostic examination and guiding a biopsy with stereotactic MBI are provided.
	claims	1. A variable stop apparatus for arrangement between an X-ray source and an object to be measured in a Computed-Tomography (CT) scanner, the variable stop apparatus comprising:a stop carrier including at least two stops and being pivotable about a pivot axis;each of the at least two stops being configured to be individually brought into a predetermined angular position by pivoting the stop carrier; andat least two of the at least two stops being arranged at different longitudinal positions in a longitudinal direction defined by the pivot axis. 2. The variable stop apparatus as claimed in claim 1, wherein the at least two stops have at least one of different stop shapes or stop dimensions, respectively. 3. The variable stop apparatus as claimed in claim 1, wherein the different longitudinal positions are selected depending on at least one of a stop shape, a stop dimension, and a focal spot size. 4. The variable stop apparatus as claimed in claim 1, wherein:the stop carrier includes at least one tube, andone of the at least two stops is arranged in a cavity of the at least one tube. 5. The variable stop apparatus as claimed in claim 1, wherein:the stop carrier includes at least two planes which are offset with respect to one another in the longitudinal direction,each of the at least two planes extends in a direction transverse to the pivot axis, andeach of the at least two planes defines an exit opening of one of the at least two stops, respectively. 6. The variable stop apparatus as claimed in claim 1, further comprising:a motor configured to drive the stop carrier and to thereby bring one of the at least two stops into the predetermined angular position. 7. The variable stop apparatus as claimed in claim 6, further comprising:a filter arrangement arranged at a distance from the stop carrier and configured to bring individual filters into the predetermined angular position by pivoting the filter arrangement about the pivot axis to permit an X-ray beam to pass through a filter in its predetermined angular position and through an aperture of a stop of the at least two stops in its predetermined angular position during operation. 8. The variable stop apparatus as claimed in claim 7, wherein the motor is configured to drive both the stop carrier and the filter arrangement. 9. A CT-scanner comprising:the variable stop apparatus as claimed in claim 1, the variable stop apparatus being arranged to permit the at least two stops positioned at the predetermined angular position to be located in the beam path between a focal spot of the X-ray source of the CT-scanner and the object to be measured.
	abstract	A corrector (1) for the axial and off-axial beam path of a particle-optical system, comprises a first (10) and a second (20) correction piece, which are disposed one behind the other in the beam path (2) on an optical axis (3). Each correction piece (10, 20) comprises four successive multipole elements (11, 12, 13, 14; 24, 23, 22, 21) disposed symmetrically with respect to a center plane (5) and with the following fields: wherein the first (11; 24) and the fourth (14; 21) multipole elements of the multipole elements (11, 12, 13, 14; 24, 23, 22, 21) are used to generate quadrupole fields (11′, 14′; 24′, 21′) and the second (12; 23) and third (13; 22) are used to generate octupole fields (12′″, 13′″; 23′″,22′″) and quadrupole fields (12′, 13′; 23′,22′), wherein the latter are superposed magnetic (12′, 13′; 23′, 22′) and electric fields (12″, 13″; 23″, 22″), wherein the quadrupole fields (11′, 12′, 13′, 14′; 24′, 23′, 22′, 21′) of all four multipole elements (11, 12, 13, 14; 24, 23, 22,21) are rotated from one to the next through 90°. An astigmatism of third order is corrected by a central multipole element disposed in the center plane and generating an octupole field.
	abstract	A nuclear reactor (10) includes a vessel (12) containing a primary liquid, a core (14) comprising nuclear fuel and arranged in the internal volume of the vessel (12), at least one primary pump generating a main primary flow (56) of primary liquid in the vessel (12), at least one control member (16) for controlling the reactivity of the core (14), at least one movement mechanism (18) for moving the control member (16), arranged in the internal volume of the vessel (12) and linked to the control member (16), and a pressurizer (20) situated in a top portion of the vessel (12). The movement mechanism (18) comprises an electrical actuator and a transmission mechanism. The electrical actuator is completely immersed in the primary fluid and situated outside the main primary flow (56).
	abstract	Aspects of a multiple layer multileaf collimator capable of improving resolution for coverage of a target during radiation therapy are described. A multiple layer multileaf collimator includes a first layer of multiple elongated radiation blocking leaves supported by a first frame for individual leaf positioning in a first direction. The multiple layer multileaf collimator further includes a to second layer of multiple elongated radiation blocking leaves supported by a second frame for individual leaf positioning in a second direction, the second direction offset at a desired angle relative to the first direction, wherein the individual leaves of the first and second layers conform more closely with a target shape to improve resolution. Further, the second layer is positioned above the first layer and provides leakage coverage for the multiple elongated radiation blocking leaves of the first layer. The multiple layer multileaf collimator is not limited to a single type of multileaf collimator and thus is suitable for use in a variety of multileaf collimator designs, including single focus and double focus multileaf collimators.
048329002	abstract	A test tool for a reactor vessel level instrumentation system which simulates and verifies the values of input signals applied to the instrumentation system. The test tool includes potentiometers for simulating the signals produced by resistance temperature detectors, switches for simulating pump status and isolator overrange limit signals, a power supply, resistors and potentiometers for simulating temperature hot sensors and a pressure wide range sensor, and potentiometers and resistors for simulating differential pressure cell signals. The invention also includes a switchable meter for verifying the values of the various input signals simulated.
	summary
051165678	claims	1. A nuclear reactor comprising: a reactor vessel; a reactor core having a fuel bundles arranged in a lower two-dimensional array, said reactor core also having fuel bundles arranged in an upper two-dimensional array, each of said fuel bundles containing vertically extending fuel rods, each of said fuel rods having a fuel section containing fissionable fuel and a plenum section for accumulating gaseous fission byproducts, said fuel rods in fuel bundles in said lower array having plenum sections below their fuel sections, said fuel rods in fuel bundles in said upper array having plenum sections above their fuel sections; and said fuel bundles in said upper array on the average being less spent than the fuel bundles in said lower array; and circulation means for circulating heat transfer fluid so that it flows axially through said bundles in said lower array toward and through said bundles of said upper array. 2. In a boiling-water reactor having a vessel for containing recirculating water having a water phase and a steam phase, a nuclear reactor core comprising multiple fuel bundles, said fuel bundles being arranged in an upper matrix and a lower matrix, each of said fuel bundles in said upper matrix being stacked on one of said fuel bundles in said lower matrix, said core being positioned within said vessel so that said coolant flows upwardly through said core from said lower matrix toward said upper matrix, said fuel bundles sharing common external dimensions so that any one bundle can be positioned in any position in either matrix. 3. A nuclear reactor as recited in claim 2 wherein each of said fuel bundles contains plural fuel rods, each of said fuel rods having a plenum end for accumulating gaseous fission byproducts, the plenum ends of said fuel rods in said upper matrix being oriented upward, the plenum ends of said fuel rods in said lower matrix being oriented downward. 4. A nuclear reactor as recited in claim 2 wherein the fuel bundles in said upper matrix are less spent than the fuel bundles in said lower matrix. 5. A nuclear reactor as recited in claim 1 wherein each fuel bundles of said upper array is stacked on a respective fuel bundle of said lower array.
	description	1. Field This embodiment relates generally to nuclear reactor internals and more particularly, to neutron source rod assemblies that are involved during the startup and shutdown phases of a reactor core. 2. Related Art The neutron source rod assemblies provide a base neutron level to ensure that X-core neutron detectors are operational and respond to source level neutrons during the period of low neutron activity such as for the initial core loading during the reactor startup. This is also the case during reactor shutdown for reloading and maintenance. The neutron source rod assemblies also permit detection of changes in the core multiplication factor during core loading and approach to criticality. The neutron sources used have included those referred to as “primary sources” and “secondary sources.” Primary sources are those which are made of neutron emitting isotopes in the form in which they are initially placed in the reactor core during initial core loading. Secondary sources are those which are made of initially non-neutron emitting materials, which become neutron emitters during its residence in the first cycle of operation in the reactor core. The secondary sources are the neutron sources that are used during the subsequent shutdowns until the end of life of the secondary sources. Typical of the materials utilized for neutron sources are those including combinations of Polonium and Beryllium, Plutonium and Beryllium, Antimony and Beryllium, Americium-Beryllium and Curium, and sources including Californium. These sources can be relatively expensive. Because secondary sources are irradiated in-core, they are typically less expensive to ship than the primary sources. The secondary sources are easier to transport and handle as they are initially non-radiating. The neutron sources are utilized during core startup and shutdown to ensure the operability of monitoring and detection apparatus, such as neutron detectors aligned with the reactor core and positioned outside of the reactor vessel. This is in accordance with governmental regulations applicable to the nuclear industry which dictate that means must be provided for monitoring or otherwise measuring and maintaining control of the fission process under all operating conditions, including shutdown. Accordingly, primary neutron sources for commercial reactors have been positioned within the nuclear core, and remain within the core during at least one entire operating cycle. These neutron sources typically maintain a fixed position. In the larger reactors, the sources are inserted in selected fuel assemblies and extend within fuel assembly guide thimble tubes designed to receive movable control rod (element) assemblies. They are therefore inserted within fuel assemblies that do not receive a moveable control rod assembly. They are also disposed in assemblies close to the core periphery so as to be positioned close enough to activate the detection and monitoring apparatus outside of the reactor vessel. As the sources remain within an assembly for an entire core cycle, the primary sources, excluding those of Californium, are consumed by neutron induced fission and transmutation before the end of the first fuel cycle, when exposed to the intense neutron flux levels characteristic of power operation. Californium may continue to be active for more than one fuel cycle. As replacement of primary neutron sources with primary neutron sources is costly, the secondary sources, activated under the high neutron flux experienced during its first cycle of operation, are used as replacements. Typically, a nuclear fuel assembly comprises a bundle of nuclear fuel rods and a support skeleton for those rods. The skeleton comprises a lower nozzle, an upper nozzle and guide thimble tubes which connect the two nozzles and which are intended to receive the rods of movable control rod assemblies for controlling the neutron flux level and thus the operation of the core of the nuclear reactor. Each movable control rod assembly comprises a bundle of neutron absorbing rods which are retained by a support. This support is generally referred to as a “spider” and is constituted by an upper hub around which fins (also referred to as flukes) are distributed and provided with members for mounting the neutron absorbing rods. During an operating cycle of the core, the movable control rod assemblies will be displaced in order to introduce to a greater or lesser extent their rods into the corresponding guide thimble tubes and thus to control the reactivity in the core of the nuclear reactor. In the nuclear reactor core, some nuclear fuel assemblies are not provided with movable control rod assemblies but instead are provided with fixed core rod assemblies that are not subjected to controlled movement during an operating cycle of the core. This is particularly the case for burnable poison rod assemblies. At least some of the rodlets thereof comprise burnable neutron poison rodlets which will allow the concentration of boron dissolved in the water of the cooling system to be reduced, primarily at the beginning of a cycle. This is also the case for thimble plug rod assemblies with which some fuel assemblies are provided. The rodlets of these thimble plug rod assemblies occupy the guide thimble tubes of the relevant fuel assemblies in order to limit the hydraulic flow. Typically, at least some of the thimble plug rod assemblies and/or some of the burnable neutron poison rod assemblies are provided with neutron source elements and at least one of the neutron source elements may be a primary neutron source element. Each of the assemblies containing a primary source element, also referred to as a primary neutron source rod assembly, has at least one primary source rodlet assembly that contains a primary radioactive material such as Californium-252 source material, inside a source capsule assembly, which spontaneously emits neutrons and is used for one cycle during the initial core loading and reactor start-up. After the first cycle of operation, throughout the remaining cycles, neutrons are supplied by the secondary neutron source rod assemblies, as mentioned above. The primary neutron source rod assemblies are typically removed after the first cycle, but can remain in the core through the first three cycles and are then retired with the spent fuel assembly that they occupied. Typically, the primary neutron source rod assembly includes at least one primary neutron source rodlet assembly and fifteen to twenty-three (depending on fuel assembly array type) core component spacer rodlets (also known as thimble plug rodlets) or burnable neutron poison rodlets, connected to a stationary spider assembly or hold down assembly (mounting assembly). Such a mounting assembly is described in U.S. Patent Publication 2010/0111243, published May 6, 2010. The thimble plug rodlets or burnable neutron poison rodlets increase the weight to aid the insertion of the primary neutron source assembly into a fuel assembly. The primary neutron source rodlet assembly is typically fabricated by a subcontract manufacturer while the remainder of the primary neutron source rod assembly (core component assembly) is fabricated and assembled by the nuclear reactor system original equipment manufacturer (OEM). Typically, the primary source rodlet assembly component parts are supplied by the reactor original equipment manufacturer, and the subcontract manufacturer assembles them along with the source capsule assembly according to approved procedures. The core component assembly, which includes the mounting assembly and thimble plug rodlets or burnable neutron poison rodlets, is fabricated by the reactor original equipment manufacturer. The core component assembly and the primary neutron source rodlet assembly are shipped separately to the assembly site location and are then assembled together on site per the appropriate assembly procedures. The site assembly procedures must address the safety requirements associate with a large irradiated component, and are typically written for specific plant sites and source configurations. Alternatively, the primary source rodlet assembly could be manufactured by the reactor original equipment manufacturer if hot cell facilities are available, but even then it's likely the primary neutron source rodlet assembly and the remainder of the primary neutron source rod assembly (core component assembly) would be shipped separately due to the differences in the packaging and shipping requirements. The primary neutron source rodlet assembly typically comprises a top extension end plug which is adapted to be connected to the stationary spider assembly or hold down assembly, a stainless steel cladding, a bottom end plug and a source capsule assembly held in a selected location with stainless steel or aluminum oxide spacers. Sometimes there is a spring clip to hold things together. There is a stainless steel protective cap used to protect the upper end plug threads during shipping. However, the cap is discarded once the primary neutron source rodlet assembly is assembled into the core component assembly. The source capsule assembly consists of inner and outer capsules encasing a neutron source material. The source material, Californium Cf252, for example, is used in the form of Californium Oxalate/Palladium composite wire with nearly 1.19 millimeter×1.19 millimeter square cross section that will pass through a 1.91 millimeter diameter hole. The individual wire is then cropped into segments containing approximately 200-500 micrograms of Californium Cf252 depending on the need of source strength at start-up. Sufficient amounts of wire, producing a calculated neutron emission of the required source, are sealed in the inner capsule. Some neutron emission strength requirements will result in a two-wire case and some will be acceptable with a one-wire case. The source capsule assemblies are made of type 308 stainless steel and sealed hermetically by welding. The capsule assemblies may also be made of zirconium alloy or a similar compatible material. A Californium Oxalate/Palladium wire is captured inside the inner capsule assembly. Sometimes the inner and/or outer capsule is back-filled with helium for better heat transfer. The source capsule assembly is designed to withstand core operational conditions, such as temperature, pressure and irradiation effects. The source capsule is also designed to safely reside in the spent fuel pool for the rest of the plant life. The primary source rodlet assembly must contain a sufficient curie level of Californium-252 to provide count rates of at least two counts per second at the nearest source range detector for at least six months after the initial start-up of the first reactor cycle. The axial location of the center of the source material should be approximately aligned with the axial location of the center of the source range detectors on the outside of the reactor vessel. FIG. 1 shows the current design flow chart. The primary neutron source rodlet assembly component parts are typically supplied by the reactor original equipment manufacturer and assembled by a subcontract manufacturer along with the source capsule assembly, in accordance with approved procedures. The core component assembly, which includes the thimble plug rodlets and/or burnable neutron poison rodlets and mounting assembly, is fabricated and assembled by the reactor original equipment manufacturer. The core component assemblies and the primary neutron source rodlet assemblies are shipped separately to the site location and then assembled together on site. The site assembly procedures must address the safety requirements associated with a large irradiated component, and are typically written for specific plant and source configurations. There are a number of disadvantages associated with the current design and manufacturing process. First of all, the primary neutron source rodlet assemblies are shipped in a special shipping container that is about fifteen to twenty feet long and about six feet in diameter. The container is shipped to the assembly site by air, because time is of the essence, and, not all air carriers are equipped and licensed to handle such a large container. In addition, the cost for such a shipment is considerably high, especially for overseas shipments. Secondly, a large enough hot cell is required to accommodate the entire primary neutron source rodlet assembly during the welding of the upper end plug. Also, testing of the upper weld needs to be performed in the same hot cell. However, the hot cell is not required when the lower end plug is welded, because that occurs before the source capsule assembly is encapsulated in the rodlet. Thirdly, once the work on the primary source rodlet assemblies in the hot cell is complete, they are transferred to the large shipping container. During this transfer, there is a significant risk of over exposure to the operators as the primary source rodlet assembly needs to leave the hot cell before it is inserted into the shipping container. Lastly, special equipment is required at the site to handle the large shipping container. Accordingly, a new neutron source rod assembly design is desired that will facilitate an improved manufacturing process that will overcome the foregoing disadvantages. Additionally, a new neutron source rod assembly design is desired that will reduce the size and awkwardness of the irradiating components that requires special handling when shipped to the assembly site. Furthermore, a new manufacturing process for the neutron source rod assemblies is desired that reduces the cost and radiation exposure encountered in handling and shipping the individual assemblies to the assembly site. The foregoing objects are achieved employing a new neutron source rod assembly design for a nuclear reactor that has a separate neutron source positioning rodlet assembly and source capsule assembly. The neutron source positioning rodlet assembly has an upper coupling for connecting to a mounting assembly and an elongated substantially round body sized to slidingly fit within a guide thimble tube of a nuclear fuel assembly. The body extends a preselected distance from the upper coupling along an axis coinciding with an elongated dimension of the substantially round body and terminates in a lower coupling. The neutron source rod assembly further includes a source capsule assembly which sealably encloses a neutron source material. The source capsule assembly is sized to slidingly fit within the guide thimble tube and has an upper coupling configured to mate with the lower couplings of the neutron source positioning rodlet assembly. The neutron source positioning rodlet assembly and the source capsule assembly are capable of being shipped independently of each other and fixedly connected to each other at an assembly site. Preferably, the preselected distance that the body of the neutron source positioning rodlet assembly extends from the mounting assembly is chosen to position the source capsule assembly at a desired elevation in the core relative to the elevation of the source range X-core detectors. In one embodiment, the neutron source positioning rodlet assembly lower coupling and the source capsule assembly upper coupling are mechanical couplings that are configured to mate with each other. Preferably, the neutron source positioning rodlet assembly lower coupling is one of either a male or female threaded coupling and the source capsule assembly upper coupling is the other of the male or female threaded coupling. Desirably, the source capsule assembly is not substantially larger than necessary to contain sufficient neutron source material to provide the neutrons required for a specified X-core source range detector count rate during reactor startup. In one embodiment of the neutron source rod assembly, the neutron source positioning rodlet is a solid rod. In another embodiment of the neutron source rod assembly, the neutron source positioning rodlet assembly is, at least in part, formed from a hollow tube that is capped at each end. Preferably, in the latter embodiment, the neutron source material in the source capsule assembly is a primary neutron source material and the hollow tube contains a secondary neutron source material. The invention also contemplates a method of manufacturing a neutron source assembly comprising a mounting assembly, a plurality of thimble plug rodlets (and/or burnable neutron poison rodlets), a neutron source positioning rodlet and a source capsule. The method includes the step of manufacturing the mounting assembly, the plurality of thimble plug rodlets (and/or burnable neutron poison rodlets) and the neutron source positioning rodlet assembly in a first manufacturing facility remote from an assembly site at which the neutron source assembly is intended to be inserted into a fuel assembly. As part of the foregoing manufacturing step, the neutron source positioning rodlet is formed to have an upper coupling to connect to the mounting assembly and an elongated, substantially round body that is sized to slidingly fit within a guide thimble tube of a nuclear fuel assembly. The body of the neutron source positioning rodlet assembly extends a preselected distance from the upper coupling along an axis coinciding with an elongated dimension of the substantially round body and terminates in a lower coupling. The method also includes the step of manufacturing the source capsule assembly in a second manufacturing facility remote from the assembly site, with the source capsule assembly sealably enclosing a source material. The source capsule assembly is sized to slidably fit within the guide thimble tube at the assembly site and has an upper coupling configured to mate with the lower coupling of the neutron source positioning rodlet assembly. Desirably, the preselected distance substantially extends from the mounting assembly to an elevation in the fuel assembly at which the neutron source material is to be situated. The method further includes the steps of shipping the mounting assembly, the plurality of thimble plug rodlets (and/or burnable neutron poison rodlets) and the neutron source positioning rodlet assembly to the assembly site; shipping the source capsule assembly to the assembly site; assembling the source capsule assembly to the lower coupling of the neutron source positioning rodlet assembly at the assembly site; and inserting the neutron source rod assembly into a fuel assembly at the assembly site. In one embodiment, the assembly site is a nuclear reactor at which the neutron source rod assembly is to be used. In still another embodiment, the assembly site is a nuclear fuel assembly manufacturing facility. In addition, in one embodiment, the mounting assembly, the plurality of thimble plug rodlets (and/or burnable neutron poison rodlets) and the neutron source positioning rodlet assembly are assembled together at the first manufacturing facility. In another embodiment, the mounting assembly, the plurality of thimble plug rodlets (and/or burnable neutron poison rodlets) and the neutron source positioning rodlet assemblies are assembled together at the assembly site. FIG. 2 shows a manufacturing flow chart of the preferred embodiment. The major differences between FIGS. 1 and 2 is that the neutron source rodlet assembly, illustrated in FIGS. 5 and 6, will have a source capsule assembly, shown in FIGS. 3 and 4, that is not encapsulated within the cladding of the neutron source positioning rodlet assembly portion of the neutron source rodlet assembly. Referring to FIGS. 5 and 6, the neutron source rodlet assembly 10 comprises the neutron source positioning rodlet assembly 12 and the source capsule assembly 14 which is shown in more detail in FIGS. 3 and 4. The neutron source positioning rodlet assembly 12 and the source capsule assembly 14 are designed such that their assembly together is feasible at the assembly site at which they are intended to be employed. The neutron source positioning rod assembly 12 preferably is either a solid or hollow cladding 16 constructed from stainless steel or zirconium alloy or similar compatible material of such a length that will axially position the source 18 in a desired location at the periphery of the core of the reactor. The lower end plug 20 of the neutron source positioning rodlet assembly 12 which is generally illustrated in FIG. 6 and shown in more detail in FIG. 7, has a threaded hole and a unique design feature 24 that is designed to connect securely to the source capsule assembly 14, though it should be appreciated that other forms of attachment may also be used. The unique locking feature 24 is a series of spaced inclined planes or curved surfaces 26 that mate with corresponding spaced inclined planes or curved surfaces 28 on the interface 30 of the source capsule assembly 14 with the neutron source positioning rod assembly 12. The interface 30 is better shown in FIG. 8 and includes a male threaded stud 32 that is designed to mate with the threaded hole 22 on the lower end plug of the neutron source positioning rodlet assembly 12. The source capsule assembly shown in more detail in FIGS. 3 and 4 includes outer and inner capsules, respectively 34 and 36. As mentioned above, the outer capsule 34 has a threaded stud 32 on one end that will be used to screw the source capsule assembly 14 into the neutron source positioning rodlet assembly at the assembly site location. The inner capsule 36 remains similar to the standard inner capsule currently employed and is sealed on three sides and closed at its lower end with an end plug 38. The end plug captures the source material 18 within the inner capsule 36. The source material 18, such as Californium Cf252, is held in position by an optional spacer 40. The lower end of the outer capsule 34 is an end plug 42 with a bullet nose 44 for easy insertion of the neutron source rodlet assembly into the guide thimble tubes within a fuel assembly. The lower end plug is fusion welded to the cladding of the outer capsule 34 at the interface 46, though it should be appreciated that other forms of attachment may be used. The total axial length of the source capsule assembly 14 is to be kept as short as is required to support the source material 18 to reduce the cost of handling and shipping a radioactive component. The full length of the neutron source positioning rodlet assembly and the relative dimensions of its component parts can be better appreciated from FIG. 5. FIG. 6 shows an enlarged view in foreshortened form of the component parts with the interfaces of the source capsule assembly 14 and its lower end plug 42, of the neutron source positioning rodlet assembly 12, its lower end plug 20 and its upper end plug 48 fusion welded though it should be appreciated that other forms of attachment may also be used. The interface 30 of the neutron source positioning rodlet assembly 12 and the source capsule assembly 14 are screwed together until their inclined planes or curved surfaces 26 and 28 snap over each other with the raised (vertical or inclined) sides abutting to lock in position. It should be noted that there is no need for an upper end plug 48 and lower end plug 20 if the neutron source position rodlets are made of solid material and a secondary neutron source is not positioned within the neutron source position rodlets as hereafter described. In such case the required features for the upper and lower couplings may directly be machined. The design of this invention thus enables the manufacturing requirements of the source capsule assembly to be satisfied by a subcontract manufacturer and more cost effectively shipped to the assembly site where it can be assembled with the remaining components of the neutron source rod assembly (core component assembly). The dimension of the source capsule assembly is in the order of 1.5+/−0.5 inches (3.81+/−1.27 cms.) long and 0.5 inches (1.27 cms.) in diameter. Therefore, the dimension of a shipping container would be relatively small and easier and less costly to handle. The expected size of the shipping container would be about five feet (1.5 meters) long and six feet (1.83 meters) in diameter. Thus, there will be more air carriers that are licensed and can handle this size container. The expected shipping costs will be lower and there will be more options for subcontract manufacturers that can manufacture the capsule assembly since a much smaller hot cell is required than is currently needed. The neutron source positioning rodlet assembly, shown in FIGS. 5 and 6, and the remaining neutron source rod assembly (core component assembly), which is shown in FIG. 9, can then be manufactured by the reactor original equipment manufacturer. The core component assembly, which will include the neutron source positioning rodlet assemblies (without the source capsule assemblies) will be assembled by the reactor original equipment manufacturer and shipped to the site separately from the source capsule assembly. Shipping the non radiated assemblies is a routine task. A neutron source rod assembly 50 in the form of a stationary spider assembly is shown in FIG. 9. Nevertheless, it should be appreciated that for the purposes of this embodiment a hold down assembly could also have been shown without detracting from this concept or altering the design of the neutron source rod assembly other than the coupling 70. The coupling 70, shown in FIG. 6 is intended to mate with a hold down assembly rather than a spider assembly. For the purpose of convenience either the hold down assembly or the spider assembly may hereafter be referred to as a mounting assembly. The neutron source rod assembly 50 principally comprises a plurality of rods 52 at least one of which is a neutron source rodlet assembly 10, and a support 54 (mounting assembly). The support 54 has a spider shape which is generally similar to that used in the prior art for moveable neutron absorber rod assemblies, with the exceptions noted below. The support 54 which can therefore be referred to as a “spider assembly,” principally comprises an upper hub 56 whose longitudinal center axis C is intended to be oriented vertically when the neutron source rod assembly 50 is arranged on a nuclear fuel assembly in a nuclear reactor core; fins or flukes 58 which extend radially outward from the hub 56 and which are distributed angularly in a substantially regular manner about the axis; and coupling systems 60 for mounting the rods 52 on the support 54. At least one of the coupling systems 60 mates with a mounting coupling 70 on the upper end plug 48 of the neutron source positioning rodlet assembly 12. One such coupling 70 intended to mate with a hold down assembly is shown in FIG. 6. The support 54 is produced from a metal such as stainless steel which can withstand a high radiation exposure. The upper hub 56 has a hollow cylindrical shape with a circular base. It comprises a lower portion 62 from which the fins 58 extend. This lower portion 62 is, for example, integral with the fins 58. The lower portion 62 of the hub 56 and the fins 58 can be produced by means of molding, machining, or electro-erosion. In one embodiment, the support 54 further comprises a back-up ring 64 that rests on the upper nozzle of the fuel assemblies with which the neutron source rod assembly is intended to be associated with. The ring 64 may comprise a collar 66 which may press downwards against a lower edge of the hub 56. A more detailed description of one such fixed spider assembly may be found in U.S. Published Application 2010/0111243A1. In another embodiment, this invention includes a secondary neutron source 68 encapsulated within a hollow portion of the neutron source positioning rodlet assembly 12 (FIG. 5) above the source capsule assembly 14. The secondary neutron source may comprise Antimony-Beryllium (Sb—Be) pellets inside a hollow portion of the neutron source positioning rodlet assembly. A proper amount of stainless steel or aluminum oxide spacers may be employed below and above the Sb—Be pellets to achieve the desired location of the secondary neutron source when it is inserted within the fuel assembly. A spring clip or coil spring could be used to hold everything in place while creating enough plenum volume to accommodate fission gases. Alternately, the Antimony-Beryllium pellets could be placed inside a hermetically sealed stainless steel or zirconium tube with the tube then encapsulated within the hollow portion of the neutron source positioning rodlet assembly. The neutron source positioning rodlet assembly can then either be made up of a tubular cladding or a solid piece of metal having its lower section hollowed. While specific embodiments of the invention have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. For example, one or more neutron source rodlet assemblies can be supported by some other mounting assembly, respectively within the guide thimble tubes of a fuel assembly, such as from the fuel assembly upper nozzle or a traditional control rod drive mechanism, without the use of a spider assembly or traditional hold down device, without departing from the concept of this invention. Similarly, the embodiments are applicable to non nuclear reactor applications of neutron sources such as oil exploration, cement manufacturing, road construction, etc. Accordingly, the particular embodiments disclosed are meant to be illustrative only and not limiting as to the scope of the invention which is to be given the full breadth of the appended claims and any and all equivalents thereof.
	claims	1. An X-ray detection apparatus comprising:a sample support unit;an X-ray irradiation unit, which is located with an exit of X-rays faced to a predetermined part of the sample support unit, structured to irradiate a sample supported by the sample support unit with X-rays;an X-ray detector, which is located with an entrance of X-rays faced to the predetermined part of the sample support unit, structured to detect fluorescent X-rays generated from the sample;a collimator structured to narrow X-rays to be used for irradiation of the sample by the X-ray irradiation unit; anda shield disposed to block X-rays emitted from the X-ray irradiation unit from passing through a path linking the exit of the X-ray irradiation unit with the entrance of the X-ray detector in a straight line, and the shield being further disposed to block fluorescent X-rays generated by the collimator or scattered X-rays generated by the collimator from passing through a path linking an arbitrary part of the collimator with the entrance of the X-ray detector in a straight line. 2. The X-ray detection apparatus according to claim 1,wherein the shield includes:a first shielding member configured to block X-rays passing through a path linking the exit with the entrance; anda second shielding member configured to block X-rays passing through a path linking the first shielding member and the collimator with the entrance. 3. The X-ray detection apparatus according to claim 2,wherein the collimator has a plate-like shape, andthe shield is projected from both faces of the collimator. 4. The X-ray detection apparatus according to claim 2,wherein the shield has a shape not to block an X-ray path from a sample supported by the sample support unit to the entrance. 5. The X-ray detection apparatus according to claim 2,wherein the shield is joined with the collimator. 6. The X-ray detection apparatus according to claim 5,wherein the collimator includes a plurality of apertures configured to narrow X-rays, andthe shield and the collimator move to change an aperture through which X-rays pass. 7. The X-ray detection apparatus according to claim 1,wherein the collimator has a plate-like shape, andthe shield is projected from both faces of the collimator. 8. The X-ray detection apparatus according to claim 1,wherein the shield has a shape not to block an X-ray path from a sample supported by the sample support unit to the entrance. 9. The X-ray detection apparatus according to claim 1,wherein the shield is joined with the collimator. 10. The X-ray detection apparatus according to claim 9,wherein the collimator includes a plurality of apertures configured to narrow X-rays, andthe shield and the collimator move to change an aperture through which X-rays pass.
	description	This application is a continuation of pending International Application No. PCT/KR2009/000451, entitled “Apparatus and Method for Repairing Photo Mask,” which was filed on Jan. 30, 2009, the entire contents of which are hereby incorporated by reference for all purposes. 1. Field Embodiments relate to an apparatus and a method for repairing a photo mask. 2. Description of the Related Art An integrated circuit (IC) may be manufactured through steps of circuit design, wafer fabrication, test, and packaging. A layout may be formed, which is a set of patterns to be transferred to a silicon wafer. Such patterns may be formed through the use of photolithographic process using photo masks or reticles. A photo mask may include a transparent fused silica substrate on which chromium patterns are formed. Defects in a manufactured photo mask can be a source of yield reduction in integrated circuit (IC) process. These defects may include contaminations, chromium spots, apertures, residues, lack of adhesion, depressions, or scratches, which may be generated during a photo mask design process, a photo mask manufacturing process, and subsequent wafer processing. It is a feature of an embodiment to provide an apparatus and/or a method for precisely repairing a photo mask having reduced width. It is another feature of an embodiment to provide an apparatus and/or a method for precisely repairing a photo mask using a probe of an atomic force microscope. At least one of the above and other features and advantages may be realized by providing an apparatus for repairing a photo mask, including a repairing atomic force microscope configured to repair a defective portion of the photo mask in a photo mask repair process, an electron microscope configured to navigate the repairing atomic electron microscope to the defective portion of the photo mask and to observe the photo mask repair process, and an imaging atomic microscope configured to image in-situ a shape of a repaired photo mask. The apparatus may further include an incident angle controller configured to control an incident angle of an electron gun of the electron microscope. The apparatus may further include a replacement probe loading part configured to load a replacement probe to replace the replacement probe for a machining probe of the repairing atomic force microscope according to abrasion of the machining probe. The apparatus may further include an optical microscope configured to observe an approach of a probe of the repairing atomic force microscope to the photo mask. The apparatus may further include an ion beam device configured to assist in repair of the photo mask by a machining probe of the repairing atomic force microscope. At least one of the above and other features and advantages may also be realized by providing a method for repairing a photo mask, the method including locating a machining probe of a repairing atomic force microscope at a defective portion of a photo mask, reciprocating the machining probe to remove the defective portion of the photo mask, using a scanning electron microscope to observe a photo mask repair process of the machining probe, and imaging in-situ a shape of a repaired photo mask using an imaging probe of an imaging atomic microscope, the imaging probe being different from the machining probe. The method may further include imaging the defective portion of the photo mask by the machining probe or the imaging probe before removing the defective portion of the photo mask. Korean Patent Application No. 10-2008-0009662, filed on Jan. 30, 2008, in the Korean Intellectual Property Office, and entitled: “Apparatus and Method for Repairing Photo Mask,” is incorporated by reference herein in its entirety. Example embodiments will now be described more fully hereinafter with reference to the accompanying drawings; however, they may be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawing figures, the dimensions of layers and regions may be exaggerated for clarity of illustration. It will also be understood that when a layer or element is referred to as being “on” another layer or substrate, it can be directly on the other layer or substrate, or intervening layers may also be present. Further, it will be understood that when a layer is referred to as being “under” another layer, it can be directly under, and one or more intervening layers may also be present. In addition, it will also be understood that when a layer is referred to as being “between” two layers, it can be the only layer between the two layers, or one or more intervening layers may also be present. Like reference numerals refer to like elements throughout. FIG. 1 illustrates a schematic diagram of an apparatus for repairing a photo mask according to embodiments, and FIGS. 2 and 3 illustrate an apparatus for repairing the photo mask according to embodiments. Referring to FIGS. 1, 2 and 3, the apparatus according to an embodiment may include a loading table 103 for loading a photo mask 101 to be repaired and a repair unit on the loading table 103. The photo mask 101, the loading table 103, and the repair unit may be disposed inside a vacuum chamber 107. The loading table 103 may be an XY stage which is translatable in X and Y axis directions. The loading table 103 may be fixed to the vacuum chamber 107 via a rotation stage 105. The rotation stage 105 may rotate with respect to a rotation shaft (not shown) fixed to the vacuum chamber 107. Thus, the photo mask 101 loaded on the loading table 103 may travel in the X and Y axis directions and rotate. The repair unit may be provided on the loading table 103 and may include a repairing atomic force microscope (AFM) 112, an imaging atomic force microscope (AFM) 114, a replacement atomic force microscope (AFM) probe loading part 115 (hereinafter referred to “replacement probe loading part”), a scanning electron microscope (SEM) 116, an optical microscope 117, an ion beam device 119, and a control part (not shown) for control thereof. The repairing AFM 112, the imaging AFM 114, and the replacement probe loading part 115 may be fixed to the rotation stage 105 on the loading table 103. Thus, the photo mask 101 may be loaded between the repairing AFM 112 and the loading table 103, and/or between the imaging AFM 114 and the loading table 103. The repairing AFM 112 may be provided to repair a defective portion of the photo mask 101. The repairing AFM 112 may include a machining probe 112a, a probe driver 112b for positioning the machining probe 112a in the X and Y axis directions, and a driver (not shown) for the control of reciprocation of the machining probe 112a. The probe driver 112b may enable the machining probe 112a to be precisely disposed at the defective portion of the photo mask 101. The machining probe 112a may be reciprocated and/or scanned by a generally-known method of driving an atomic force microscope. The driver (not shown) may reciprocate the machining probe 112a such that the machining probe 112a removes the defective portion of the photo mask 101. Apart from the repairing AFM 112, the imaging AFM 114 may be additionally provided for in-situ monitoring the shape of a repaired photo mask 101. The imaging AFM 114 may include an imaging probe 114a, a probe driver 114b for positioning the imaging probe 114a in the X and Y axis directions, and a driver (not shown) for the control of the reciprocation of the imaging probe 114a. The machining probe 112a may be easily worn by the interaction with a pattern of the photo mask 101. Thus, an image obtained by the machining probe 112a may be distorted from a real image. In this regard, if the photo mask 101 is imaged using the imaging probe 114a different from the machining probe 112a, the repaired patterns on the photo mask 101 may be accurately imaged. The driver (not shown) may allow the imaging probe 114a to be reciprocated and/or scanned by a generally-known method of driving an AFM. The machining probe 112a and the imaging probe 114a may be disposed toward the photo mask 101 in an inclined direction relative to a surface of the photo mask 101. As the machining probe 112a is worn, the worn machining probe 112a may need to be replaced by a new machining probe (not shown). Accordingly, while loading the new machining probe, the replacement probe loading part 115 may replace the worn machining probe 112a by the new machining probe in accordance with the command of the control part. Spatial resolution of the SEM 116 may be at least 200 times higher than that of a typical optical microscope. Focal depth of the SEM 116 may be at least 1000 times greater than that of a typical optical microscope. Magnification change of the SEM 116 may be conducted more freely than a typical optical microscope. The SEM 116 may allow a user to rapidly observe a wider and deeper region than an AFM. The SEM 116 may be provided to find out a defective portion of the photo mask 101. The SEM 116 may be used to rapidly navigate the machining probe 112a to the defective portion of the photo mask 101. Thus, while visually observing the photo mask 101 and/or the repairing AFM 112 through SEM 116, the user may find out or identify the defective portion of the photo mask 101, and may locate the machining probe 112a at the defective portion of the photo mask 101. Further, the SEM 116 may allow the user to observe a repair process of the photo mask 101 being performed by the repairing AFM 112, and to inspect a degree of wear of the machining probe 112a. The optical microscope 117 is provided to observe the approach of the probes 112a and/or 114a to the photo mask 101. For example, the defective portion detected by a defect inspection system may be roughly located with the aid of the optical microscope 117. When the photo mask 101 is repaired using the repairing AFM 112, the ion beam device 119 may assist the repair of the photo mask 101. The SEM 116, the optical microscope 117, and the ion beam device 119 may be fixed to the vacuum chamber 107. An incident angle of an electron gun of the SEM 116 may be controlled by using an electron gun incident angle controller, e.g., by driving the rotation stage 105. The control of the incident angle may prevent the optical microscope or AFM and ion beam devices from covering up the defective portion of the photo mask 101. Thus, the repair process of the photo mask 101 may be observed in real time. The control part (not shown) may display images of the AFM 114, the SEM 116, and the optical microscope 117, and may control the driving of the repairing AFM 112, the replacement probe loading part 115, and the ion beam device 119. Referring to FIG. 4, according to another embodiment, an apparatus for repairing a photo mask may further include a micro electron column 120 and a micro electron column sliding stage 121. The micro electron column 120 may be provided to monitor the degree of wear of the machining probe 112a, and the micro electron column sliding stage 121 may be provided to allow the micro electron column 120 to approach the machining probe 112a. An angle of the machining probe 112a with respect to the micro electron column 120 may be controlled by driving the rotation stage 105 to precisely check the degree of wear of the machining probe 112a. The control of the angle may prevent the optical microscope or AFM and ion beam devices from covering up the machining probe 112a. Before driving the rotation stage 105, the photo mask 101 may be translated by driving the loading table 103. Therefore, the rotation stage may be freely rotated. Referring to FIG. 5, a method for repairing a photo mask according to example embodiments will now be described. A defect position reported by the defect inspection system may be roughly navigated to using the electron microscope 116 or the optical microscope 117. The electron microscope may have a superior spatial resolution relative to a typical optical microscope, and may thus allow the user to rapidly observe a wider and deeper region on the photo mask. Thus, a defect position of a photo mask 101 may be found out or identified rapidly, i.e., high-speed mask navigation may be achieved. Around the identified defect position, a defective portion of the photo mask 101 may be imaged using the machining probe 112a or the imaging probe 112b to precisely locate the defect position of the photo mask 101 (S11). The machining probe 112a may be located at the defective portion of the photo mask 101, based on the navigation result of the SEM 116 or the optical microscope 117 (S12). Using, e.g., reciprocal operation of the machining probe 112a, the defective portion of the photo mask 101 may be removed to perform a repair work (S13). Generally, real-time imaging of a photo mask repair process may not be possible, such that the repair work must be stopped for a while to determine an optimal endpoint of the repairing work through imaging with the machining probe 112a. In contrast, according to example embodiments, a repair process may be observed with the aid of SEM 116 while the machining probe 112a is operating, i.e., the repair work for the photo mask 101 may be seen using the SEM 116 in real time. Thus, the optimal endpoint of the repairing work may be determined efficiently. Generally, a probe and a photo mask may need to be separated during repair work to check an abrasion state of the machining probe, and it may be difficult to locate the separated probe and photo mask at their original positions. In contrast, according to example embodiments, the machining probe may be replaced without changing position of the photo mask. Thus, difficulties in realigning the photo mask may be reduced or eliminated. In further detail, as the repair work is repeated, a defect of the photo mask 101 may be corrected but the machining probe 112a may become worn. The abrasion and/or contamination state of the machining probe 112a may be observed using the SEM 116. If the abrasion state of the machining probe 112a is not good, the repair work may be stopped and the machining probe 112a may be replaced with another probe by the replacement probe loading part 115. Generally, a repaired photo mask may be imaged using a machining probe. However, the machining probe is apt to be worn or contaminated during a repair work, deteriorating the reproducibility of an AFM image obtained by the machining probe. Thus, the probe and the photo mask may need to be separated during the repair work to monitor an abrasion state of the machining probe, and it may be difficult to locate the separated probe and photo mask at their original positions. In contrast, according to example embodiments, the repaired photo mask may be monitored in-situ using the imaging probe 114a, which may be different from the machining probe 112a (S14). Thus, according to example embodiments, by using a separate high quality probe dedicated to imaging, the repair state may be accurately examined. A pre-repaired photo mask and a repaired photo mask are shown in FIG. 6. In the figure, “D” represents a defect of the photo mask. Specifically, (a) and (c) are a top plan view and a perspective view of the pre-repaired photo mask, respectively, and (b) and (d) are a top plan view and a perspective view of the repaired photo mask, respectively. In FIG. 6, the defect (D) removal using the machining probe 112a is 3-dimensionally imaged with the imaging probe 114a. Generally, investments in terms of money and time may too great to justify discarding an already-manufactured photo mask having a defect and to make a new one instead. Thus, when defects are found, attempts may be made to repair the photo mask to render it free of critical defects before cleaning and pellicle mounting steps are carried out. Repair of a photo mask may be attempted using methods that use, e.g., laser, focused ion beam (FIB), focused electron beam (FEB), or atomic force microscope (AFM)-based nano machining (NM). In the laser method, defect materials may be removed through the process of laser ablation, but poor spatial resolution may be a limitation. In the FIB method, defect materials may be removed through physical sputtering or etching, or materials may be deposited based on a precursor. While the FIB method may have advantages in terms of spatial resolution and working time relative to the laser, a substrate may be damaged by sputtering or by gallium-ion implantation. In the FEB method, a source of a scanning electron microscope (SEM) may be used. The FEB method may be slower than the FIB method, but the FEB method may be superior in terms of spatial resolution and chemical selectivity, and may reduce the damage of a photo mask. As described above, embodiments may use both a repairing atomic force microscope (AFM) for repair and an electron microscope (SEM) for observation. Thus, according to embodiments, the interaction of the machining probe and the pattern may be observed in real time during repair work. Generally, an atomic force microscope image may have artifacts induced by the interaction of the probe with the pattern. In contrast, embodiments may provide a realistic pattern by comparing images of the atomic force microscope (AFM) and the electron microscope (SEM). In an example embodiment, an image of the repaired photo mask may be obtained using an imaging probe of an imaging atomic force microscope probe that is different from the machining probe. Use of the separate imaging probe may provide a realistic image, instead of a distorted image that could be produced by a degraded machining probe during a repair work. Moreover, according to embodiments, since all the jobs, checking and replacing an AFM probe, may be done inside a vacuum chamber, significant time savings may be achieved. As described above, embodiments relate to an apparatus and a method for repairing a photo mask using a probe of an atomic force microscope. A machining probe may be located at a defective portion of a photo mask. The defective portion of the photo mask may be removed by reciprocating the machining probe. The photo mask repair process may be observed using SEM. The shape of a repaired photo mask may be monitored in-situ using an imaging probe. The imaging probe may be different from the machining probe. Example embodiments have been disclosed herein, and although specific terms are employed, they are used and are to be interpreted in a generic and descriptive sense only and not for purpose of limitation. Accordingly, it will be understood by those of skill in the art that various changes in form and details may be made without departing from the spirit and scope of the present invention as set forth in the following claims.
043057861	abstract	A system for determining whether a self-sustaining neutron chain reaction (i.e., criticality) may occur as each successive nuclear fuel element is added to a liquid-filled tank. This is accomplished by determining whether a multiplication factor, k, approaches unity after each element is added to the tank in accordance with the equation: EQU CR=(.alpha.S)/(1-k). where:. S is the emission rate of the neutron source; PA1 .alpha. is a term that reflects the detector sensitivity as well as the attenuation of the neutron between source and detector and various geometric considerations in the tank; PA1 CR is the counting rate from a neutron detector; and PA1 k is a multiplication factor of the assembly at any given time for any given element configuration.
	abstract	Various options for improving throughput in an e-beam lithography apparatus are described. A slider lens moves in synchronism with the scanning motion of the electron beam.
	description	The present invention relates to a canister that stores and transports spent nuclear fuel, and more importantly, the embodiments relate to the apparatus and methods for achieving redundant confinement sealing of a canister. Dry nuclear spent fuel storage technology is deployed throughout the world to expand the capabilities of nuclear power plants to discharge and store spent fuel, thereby extending the operating lives of the power plants. Two fundamental classes of technology are used in dry spent fuel storage: metal casks with final closure lids that are bolted closed at the power plants after loading with spent fuel, and concrete storage casks containing metal canisters having canister final closure lids that are welded closed at the power plants following spent fuel loading. This latter technology is referred to as canister-based dry spent fuel storage technology. Canister-based dry spent fuel storage technology designs typically comply with federal regulatory requirements, among which are requirements pertaining to confinement, sealing, inspection, and evaluation or testing. In particular, the Code of Federal Regulations (CFR) requires that “[t]he spent fuel storage cask must be designed to provide redundant sealing of confinement systems.” See 10CFR72.236(e). The confinement system is defined in 10CFR72.3, as follows: “Confinement systems means those systems, including ventilation, that act as barriers between areas containing radioactive substances and the environment.” In other words, the confinement system is the boundary that is to be protected to assure that there is no release to the environment of the contained radioactive materials within the spent fuel dry storage system. The Nuclear Regulatory Commission (NRC), which enforces compliance with federal regulations, has applied the above requirements to fabrication facility-installed, confinement system welds in canister-based dry storage designs (those which are performed prior to delivery to the power plant and prior to loading with spent fuel) such that single or multi-pass welds that are inspected with NRC approved inspection methods and techniques meet the requirements of 10CFR72.236(e). However, for final closure welds on canister-based technology, which are conducted at nuclear facilities following loading of spent fuel, the application of the regulatory requirements has varied, but NRC approval of the varied approaches has been consistent with the use of approved single or multi-pass welding approaches followed by the application of approved inspection methods and techniques. Over the years, most canister-based dry storage designs have followed a path to assure compliance with redundant sealing requirements for the final canister closure at the power plant (the “field closure”) by the use of redundant lids for the final closure design. That is, two lids or closures were placed within the canister and welded to the canister shell. These lids were not required to be structurally separate (independent) and could be linked to each other by additional welding. However, approaches with and without structural independence of the redundant lids have all been approved by the NRC for compliance with federal requirements. The use of a redundant lid approach on canister-based designs leads to lid handling and installation complexities at power plants. With multiple lid handling operations, opportunities for operator injury and equipment damage are increased, and more time must be spent in higher radiation fields. Further, the use of redundant lids increases the radiation exposure of power plant personnel when compared to a single lid approach, since more time is required to handle, lift, install and weld two lids, because the first lid to be welded of a redundant lid design provides less radiation shielding to the operators, and, therefore, more radiation exposure. Such an approach may be at variance with federal regulatory requirements, if there is a reasonable alternative that reduces direct radiation levels, to wit: “Operational restrictions must be established to meet as low as reasonably achievable [known as ALARA in industry parlance, a design objective to keep operator radiation exposures reasonably low] objectives for radioactive materials in effluents and direct radiation levels associated with ISFSI or MRS operations.” (See 10CFR72.104(b).) Thus, a heretofore unaddressed need exists in the industry to improve upon the aforementioned deficiencies and inadequacies. Disclosed are the apparatus and methods for closing a canister that stores and transports spent nuclear fuel. In one embodiment, a method for closing a canister includes providing a canister shell that includes an open end and providing a weld area that is substantially on the outer circumference of the closure lid where the closure lid engages the open end of the canister shell. The method further includes welding the closure lid to the canister shell at the weld area that forms a first weld layer to close the canister and welding the closure lid to the canister shell at the weld area that forms a second weld layer substantially on top of the first weld layer to close the canister. As a further option, the method can further include welding of the closure lid to the canister shell at the weld area to form additional redundant weld layers and close the canister to assure that the composite weld layer depth and/or the number of redundant seal weld layers is achieved. As another further option, the method includes disposing a seal ring substantially above a preceding weld layer and between the canister shell and the closure lid. The method includes cooling the first, second and additional weld layers below the material-specific adhesion temperature after each layer is applied to assure the weld layers have achieved adhesion characteristics with the canister shell and closure lid, and inspecting the first, second and additional weld layers after each layer is cooled using approved methods and techniques, for example, dye-penetrant examination of the weld, to determine the quality of the weld layers and their acceptability. In one embodiment, the canister includes a canister shell that includes an open end and a basket assembly that is disposed in the canister shell. A closure lid is inserted within the open end of the canister shell. The closure lid engages the open end of the canister shell to provide a weld area that is in the proximity of the outer circumference of the closure lid. The weld area includes a first weld layer and a second weld layer. The first weld layer welds the closure lid to the canister shell at the weld area and closes the canister. The second weld layer also welds the closure lid to the canister shell at the weld area, providing a redundant closure seal, and is disposed substantially on top of the first weld layer. As a further option, the canister can include additional redundant weld layers that weld the closure lid to the canister shell at the weld area and that close the canister to assure that the composite weld layer depth and/or the number of redundant seal weld layers is achieved. As another further option, a seal ring is disposed substantially above a preceding weld layer and between the canister shell and the closure lid. The seal ring is welded to the closure lid and to the canister shell, providing another level of redundant closure sealing. Other apparatus, methods, features, and advantages of the present invention will be or become apparent to one with skill in the art upon examination of the following drawings and detailed description. It is intended that all such additional apparatus, methods, features, and advantages be included within this description, be within the scope of the present invention, and be protected by the accompanying claims. Disclosed are apparatus and methods for a canister that stores and transports spent nuclear fuel. In one embodiment, the canister includes a weld area that includes a first weld layer and a second weld layer. The first weld layer welds a closure lid to a canister shell at the weld area and closes the canister. The second weld layer also welds the closure lid to the canister shell at the weld area, providing a redundant closure seal, and is disposed substantially on top of the first weld layer. As a further option, additional weld layers can be welded at the weld area to close the canister. As another further option, the canister can include a seal ring that is disposed substantially above a preceding weld layer and between the canister shell and the closure lid. The seal ring is welded to the closure lid and to the canister shell. The disclosed process assures that the closure lid is sealed to be leak tight. Example apparatuses are first discussed with reference to the figures. Although the apparatuses are described in detail, they are provided for purposes of illustration only and various modifications are feasible. After the exemplary apparatuses have been described, examples of methods of closing the canister are provided. Referring now in more detail to the figures in which like reference numerals identify corresponding parts, FIG. 1 is a partially cut-away, perspective view of an embodiment of a canister that stores and transports nuclear spent fuel. The canister 1 is a single closure lid design of a canister-based dry storage technology. The canister 1 includes one closure lid 3 and one weld area 8 (shown in FIG. 2). The use of a single closure lid design is one approach to achieving redundant sealing of the confinement system for “field closure” of the canister 1 following loading with spent fuel or other desired content. The canister 1 includes a canister shell 9 that includes an open end 4. In an alternative embodiment, the closure lid 3 can include a port opening 6 that is adapted to receive a port cover 5 and a drain or vent member 11. In an alternative embodiment, the canister 1 can include a basket assembly 7 that is preferably disposed in the canister shell 9 before the canister is sealed. In an alternative embodiment, the canister 1 can further include a seal ring 2 that is disposed between the canister shell 9 and the closure lid 3, at the inner circumference of the canister shell 9 and at the outer circumference of the closure lid 3. The seal ring 2 can be a single piece or multiple pieces. FIG. 2 is a partially cut-away, cross-sectional, side view of an embodiment of the canister shown in FIG. 1 that includes a redundant seal for regulatory compliance. The canister shell 9 of the canister 1 includes a closure lid seating member 15 that can be integrally coupled to the canister shell. The canister 1 is adapted to be inserted with a closure lid 3 that rests on the closure lid seating member 15 of the canister 1 such that the top surface 12 of the closure lid 3 is substantially parallel to the top end 14 of the basket assembly 7. In an alternative embodiment, the closure lid seating member 15 can be integrally coupled to other internal appurtenance, such as the basket assembly 7. In an alternative embodiment, the closure lid 3 is adapted to be inserted with a drain or vent member 11 and a port cover 5. The closure lid 3 can include a drain or vent passage 10 in which the drain or vent member 11 is disposed. The drain or vent passage 10 is conformed substantially to the shape of the drain or vent member 11. The closure lid 3 further includes port cover recesses 16 that the port cover 5 rests on. The top surface of the port cover 5 is substantially parallel to the top surface 12 of the closure lid 3. Where the closure lid 3 engages the open end 4 of the canister shell 9, a weld area 8 is provided in the proximity of the outer circumference of the closure lid 3 that meets the weld depth and weld type requirements of both the design and applicable regulations, codes and standards. A first weld layer 17 welds the closure lid 3 to the canister shell 9 at the weld area 8 and closes the canister 1 as a first seal or closure to the canister 1. A second weld layer 19 welds the closure lid 3 to the canister shell 9 at the weld area 8 and closes the canister as second seal or closure to the canister 1. The second weld layer is disposed substantially on top of the first weld layer 17. The first and second weld layers 17, 19 are independent layers and seals for the canister closure. The first and second weld layers 17, 19 are single pass welds or multi-pass welds with inter-pass temperatures that meet the requirement for the specific material and the welding method or application. In an alternative embodiment, additional redundant weld layers are applied to weld the closure lid 3 to the canister shell 9 at the weld area 8 and close the canister 1 to assure that the composite weld layer depth and/or the number of redundant seal weld layers is achieved The weld layers 17, 19 are achieved using a multiple independent layer, discrete redundant inspection (MILDRI) weld approach, which is used to establish the redundant sealing for the single closure lid canister design. The MILDRI weld process is performed as follows: 1. A welding machine (not shown) designed to lay weld consistent with the canister design and weld configuration is placed in position to perform the weld in the weld area 8. 2. The welding machine provides a first weld layer 17 which is comprised of a root weld. It should be noted that multiple passes may be used to achieve the first weld layer. 3. The first weld layer 17 becomes the first independent layer and first seal for the canister closure by meeting the following acceptance criteria: a. The first weld layer 17 has been applied as a single pass weld or as a multi-pass weld with inter-pass temperatures meeting all requirements for the specific materials and welding conditions; b. The first weld layer 17 meets the depth requirements that are required by safety or other analysis. c. The first weld layer 17 is allowed to cool below some maximum temperature (in the range of the material-specific adhesion temperature) to assure the first weld layer 17 has achieved adhesion characteristics with the canister shell 9 and closure lid 3 that are suitable for independent inspection for cracks and adhesion using approved methods and techniques; d. An independent inspection of the first weld layer 17 is performed using approved methods and techniques, such as dye-penetrant examination, to determine the quality of the weld and its acceptability; e. Any weld inconsistencies, flaws, or other manifestations of lack of adhesion or weld soundness in the first weld layer 17 are reviewed, accepted, or repaired in accordance with design and procedure acceptance criteria; f. Any weld repairs of the first weld layer 17 are further inspected by similar methods to verify repair acceptance in accordance with appropriate acceptance criteria. Following completion, inspection, and acceptance of the first weld layer 17, a second weld layer 19 is applied in the weld area 8 of the closure lid 3. The second weld layer 19 is in the proximity of the outer circumference of the closure lid 3 where the closure lid 3 engages the open end 4 of the canister shell 9 and is substantially on top of the first weld layer 17. The second weld layer 19 is achieved using similar steps to those in 3a-f, as explained above, to assure that the second weld layer 19, independent inspection, and integrity requirements are met to permit the first and second weld layers 17, 19 to serve as redundant seals. In an alternative embodiment, additional weld layers can be applied to assure that the composite weld layer depth and/or the number of redundant seal weld layers is achieved using similar approaches and acceptance criteria as in step 3, explained above. In an alternative embodiment, a seal ring 2 is disposed above a preceding weld layer and between the canister shell 9 and the closure lid 3. The seal ring 2 is substantially parallel to the top end 14 of the canister 1 and top surface 12 of the closure lid 3. The seal ring is welded to the canister shell and to the closure lid 3 to form two weld surfaces 21, 23. The first and second weld surfaces 21, 23 can be single pass welds or multi-pass welds, with inter-pass temperatures that meet the requirement for the specific material and the welding method or application. The seal ring 2 provides a separate, redundant closure surface, in addition to the closure lid 3 having other weld layers. The seal ring 2 can be of a unit design or of a segmented design to facilitate handling or placement. It is further depicted in the embodiment of FIG. 2 that the closure lid 3 may be configured with an upper portion having a first lateral outer circumference that laterally intersects the weld area 8 at the bottom of the upper portion of the closure lid 3. The closure lid 3 may further be configured with a lower portion having a second lateral outer circumference that laterally intersects the weld area 8 at or near the top of the lower portion of the closure lid 3 as depicted. A magnitude of the first lateral outer circumference is less than or smaller than the second lateral outer circumference. The lower portion of the closure lid 3 is further positioned at a lower altitude relative to the upper portion of the closure lid 3. The closure lid 3 can further include a middle portion having a variable lateral outer circumference that ranges from the first lateral outer circumference to the second lateral outer circumference. In other words, as depicted in the drawing, the upper portion, middle portion, and bottom portion of the closure lid 3 create a cavity that makes up the depicted weld area 8. The weld area 8 is accordingly between the closure lid 3 and canister shell 9 at or near the top of the bottom portion of the closure lid 3 and below the bottom of the upper portion of the closure lid 3. The root welds 21, 23 of the seal ring 2 are achieved using the MILDRI weld process as mentioned above in reference to the weld layers 17, 19. It should be noted that single pass or multi-pass welds can be applied to assure that the composite weld depth is achieved. It should also be noted that the weld surfaces 21, 23 can have multiple weld layers. FIGS. 3A-C are flow diagrams that illustrate an embodiment of operation of closing the canister with a single lid having redundant seals shown in FIGS. 1 and 2. Referring now to FIG. 3A, in block 29, the method 25 for closing the canister 1 includes providing a canister shell 9 that includes an open end 4. In block 31, a closure lid 3 is inserted within the open end 4 of the canister shell 9. It should be noted that a basket assembly can be inserted into the canister before the closure lid 3 is inserted within the open end 4 of the canister shell 9. In block 33, a weld area 8 is provided that is substantially on the outer circumference of the closure lid 3 where the closure lid 3 engages the open end 4 of the canister shell 9. In block 35, the closure lid 3 is welded to the canister shell 9 at the weld area 8 that forms a first weld layer 17 to close the canister 1. In block 37, the first weld layer 17 is cooled below the material-specific adhesion temperature after the first weld layer 17 is applied to assure the first weld layer 17 has achieved adhesion characteristics with the canister shell 9 and closure lid 3. In block 39, the first weld layer 17 is inspected, after the first weld layer 17 is cooled, using approved methods and techniques, such as dye-penetrant examination of the weld, to determine the quality of the first weld layer 17 and its acceptability. In block 41, the closure lid 3 is welded to the canister shell 9 at the weld area 8 that forms a second weld layer 19, which is substantially on top of the first weld layer 17 to close the canister 1. Referring now to reference A in FIG. 3B, blocks 43 and 45 repeat steps 37 and 39 for the second weld layer 19. In block 47, additional redundant weld layers are welded at the weld area 8 to assure that the composite weld layer depth and/or the number of redundant seal weld layers are achieved. Blocks 49 and 51 repeat steps 37 and 39 for the additional weld layers. Referring now to reference B in FIG. 3C, in block 53, a seal ring is disposed above a preceding weld layer and between the canister shell 9 and the closure lid 3. In block 55, the seal ring 2 is welded to the closure lid 3 and to the canister shell 9. The welding of the seal ring 2 includes forming weld surfaces 21, 23 between the seal ring 2 to the canister shell 9 and to the closure lid 3. Weld surfaces 21, 23 can be single pass or multi-pass welds. Blocks 57 and 59 repeat steps 37 and 39 for the weld surfaces 21, 23. It should be emphasized that the above-described embodiments of the present invention, particularly, any “preferred” embodiments, are merely possible examples of implementations, set forth for a clear understanding of the principles of the invention. Many variations and modifications may be made to the above-described embodiment(s) of the invention without departing substantially from the spirit and principles of the invention. All such modifications and variations are intended to be included herein within the scope of this disclosure and the present invention and protected by the following claims.
051125650	description	DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention involves a control technique (algorithm) having time cycles which are short compared with delayed neutron lifetimes in nuclear reactors. A typical algorithm cycle in this case is of the order of 10 milliseconds. Even though the foregoing time cycle is short, an evaluation of the reactivity of the system or the instantaneous reactor period can be accomplished during same. In addition, the foregoing actuator or control technique (algorithm) can be utilized in conjunction with a "stepping drive" or actuator which can incrementally change a parameter by a fixed amount, either plus or minus one unit. The motion and/or position of the apparatus attached to the stepping drive or actuator can be used to change the reactivity of the nuclear reactor or some other parameter which affects reactivity. Thus, the foregoing control technique completes an evaluation of the state of the system in one time cycle and determines if the stepping drive should add, subtract, or make no change in the of the nuclear reactor reactivity. In effect, the total control action is completed in one time cycle. In addition, digital topology is provided as part of the foregoing control technique. Such topology permits the use of non-linear response functions in the determination of the required change in reactivity. A primary advantage of the present invention is a reduction in the number of algorithm calculations required to determine the proper control action to be taken. The short cycle times for the algorithm permit almost instantaneous correction of any errors. In addition, the use of a stepping drive or actuator eliminates the necessity for position or velocity feedback signals within the drive system. Each "step" uses the maximum capability of the actuator or drive. Furthermore, the use of digital topology based on pre-calculated functions permits the utilization of response functions which can be non-linear. In this case the system is designed to provide an output from a memory location which contains a pre-calculated value. The selection of the memory location is based on the value of an input parameter which has been converted to a digital address by conventional analog to digital techniques. Such techniques can be implemented without the use of a stored program computer system. Thus, the resulting algorithm can be implemented at significantly higher speeds and without the use of software programming. The result is a control system that is small, light weight and consumes very little power. Previous control technique have been based on the principle that when control action is required, reactivity changes should be made at the maximum rate available by the control mechanism. Typically, the control mechanism is "stepped" at its maximum rate until the reactor power is escalating on the desired period. The control mechanism then holds that period until the output from the DIGITOP (desired period) changes. The input to the DIGITOP can be reactor power, temperature of coolant, temperature of fuel or any combination of measured parameters. The control technique of the present invention produces a smooth start-up that minimizes the reactor startup time, within the constraints of the control element worth curve and the maximum speed of the control actuators. The control technique also minimizes both the motor torque requirements of the stepping motors and the number of calculations required in the control computer. These modifications provide a smooth, start-up without overshooting either the full power level or the limiting reactor start-up rate, see FIG. 3. The control technique of the present invention has been utilized with a simulation model of a nuclear reactor. The simulation used the reactivity worth curve established by the control elements as a function of position, and the results of the simulation are illustrated in FIG. 3. In this case, the control drive mechanism used a cycle time of 10 milliseconds which is the cycle time for the control computer. Until the reactor reached the demand period, the control drive mechanism was being moved one increment for each cycle. Certain modifications and improvements will occur to those skilled in the art upon reading the foregoing. It should be understood that all such modifications and improvements have been deleted herein for the sake of conciseness and readability, but are properly within the scope of the following claims.
	summary
	summary
047626640	claims	1. A method of compacting spent fuel rods from a fuel rod assembly comprising the steps of: exposing end portions of an array of fuel rods in said fuel rod assembly, passing a gripper to a fuel rod gripping position, causing said gripper to simultaneously grip the array of spent fuel rods, moving said gripper and array of fuel rods gripped thereby in an axial direction of the fuel rods relative to the fuel assembly to displace the fuel rods from the fuel rod assembly to a fuel rod release position, and reciprocating said gripper between said fuel rod gripping position wherein the fuel rods are again gripped and said fuel rod release position wherein the fuel rods are released to withdraw the fuel rods from said fuel rod assembly in said one axial direction and advance the fuel rods along the respective passages in a fuel rod directing chamber to thereby consolidate the fuel rods into a compacted configuration of a cross-sectional area smaller than the cross-sectional area occupied by the fuel rods within the fuel rod assembly. moving end portions of an array of spent fuel rods from said fuel rod assembly through respective consolidating passages to present a compacted bundle of fuel rods at a discharge end of the consolidating passages, passing a gripper along the end portion of the bundle of spent fuel rods to a fuel rod bundle gripping position, causing said gripper to grip the bundle of spent fuel rods, moving said gripper and bundle of fuel rods gripped thereby in an axial direction of the fuel rods to displace the fuel rods from the consolidating passages to a fuel rod bundle release position, and reciprocating said gripper between said gripping position wherein the fuel rods are again gripped and said release position wherein the fuel rods are released to withdraw the bundle of fuel rods from said fuel rod consolidating passages in one axial direction and advance the bundle of fuel rods into a fuel storage container wherein the fuel rod bundle has a compacted configuration of a cross-sectional area smaller than the cross-sectional area occupied by the fuel rods within the fuel rod assembly. 2. The method according to claim 1 including the further step of controlling a supply of pressurized fluid medium to said gripper to grip and release the array of fuel rods. 3. The method according to claim 1 wherein said step of passing a gripper includes passing a spaced-apart array of tubes comprised of resilient material along the outer peripheral surfaces of said fuel rods, and wherein said step of causing the gripper to simultaneously grip includes elastically deforming said array of tubes against said fuel rods. 4. The method according to claim 1 wherein said step of causing the gripper to simultaneously grip the array of fuel rods includes expanding resilient members between rows of fuel rods comprising the array of fuel rods. 5. The method according to claim 4 wherein said resilient members include oval-shaped tubular sections. 6. The method according to claim 5 wherein said gripper includes active and passive gripper elements extending between rows of fuel rods comprising said array of fuel rods. 7. The method according to claim 1 including the further step of holding the array of fuel rods while said gripper reciprocates from said fuel rod release position to said fuel rod gripping position. 8. The method according to claim 7 wherein said step of holding the array of fuel rods includes passing the array of fuel rods in a stationary gripper. 9. The method according to claim 8 including the further step of arranging said stationary gripper between said fuel rod directing chamber and said fuel rod release position of the gripper. 10. The method according to claim 1 wherein said step of moving said gripper includes supporting the gripper from said fuel rod directing chamber and reciprocating said fuel rod directing chamber to thereby reciprocate said gripper. 11. The method according to claim 1 including the further steps of passing a second gripper along an exposed end portion of a bundle of consolidated fuel rods emerging from said fuel rod directing chamber to a bundle gripping position, causing the second gripper to grip the bundle of consolidated fuel rods, moving the second gripper and the bundle of consolidated fuel rods gripped thereby in an axial direction of the fuel rods to displace the fuel rods from said fuel rod directing chamber to a fuel rod bundle release position, directing the leading end of the bundle of fuel rods into a storage container, and reciprocating the second gripper between said fuel rod bundle gripping position and said fuel rod release position to advance the bundle of fuel rods into the storage container. 12. The method according to claim 11 including the further step of holding the bundle of fuel rods while said second gripper reciprocates from said bundle release position to said bundle gripping position. 13. The method according to claim 12 wherein said step of holding includes passing the bundle of fuel rods in a stationary bundle gripper. 14. The method according to claim 13 including the further step of arranging said stationary bundle gripper between said storage container and said fuel rod bundle release position of said second gripper. 15. The method according to claim 11 wherein said step of moving said second gripper includes supporting the second gripper from said fuel rod directing chamber and reciprocating said fuel rod directing chamber to thereby reciprocate said second gripper. 16. The method according to claim 11 including the further step of feeding the bundle of consolidated fuel rods in a container having a rhombic cross-sectional configuration. 17. A method of compacting spent fuel rods from a fuel rod assembly comprising the steps of: 18. The method according to claim 17 including the further step of holding the bundle of fuel rods while said gripper reciprocates from said bundle release position to said bundle gripping position. 19. The method according to claim 18 wherein said step of holding includes passing the bundle of fuel rods in a stationary bundle gripper. 20. The method according to claim 19 including the further step of arranging said stationary bundle gripper between said storage container and said fuel rod bundle release position. 21. The method according to claim 17 wherein said step of causing said gripper to grip includes pressing a movable member against the bundle of fuel rods while confined in a cavity formed by frame members. 22. The method according to claim 21 wherein said step of causing said gripper to grip includes expanding a resilient member in the cavity of a frame wherein the bundle of fuel rods is located. 23. The method according to claim 22 wherein said resilient member surrounds the outer periphery of the bundle of fuel rods. 24. The method according to claim 17 including the further step of moving, said gripper includes supporting the gripper from said fuel rod directing chamber and reciprocating said fuel rod directing chamber to thereby reciprocate said gripper. 25. The method according to claim 17 including the further step of feeding the bundle of compacted fuel rods in a storage container having a rhombic cross-sectional configuration.
044951442	summary	BACKGROUND OF THE INVENTION The present invention generally pertains to fission chamber detector systems for monitoring neutron flux in a nuclear reactor, and is particularly directed to increasing the monitored range, improving alignment of processed signals derived from different portions of the monitored range, and providing high neutron signal sensitivity in a hostile environment. A fission chamber detector is a type of neutron detector that is preferred for use in neutron flux monitoring systems because it has been proven to have a longer life and to be more reliable than other types of neutron detectors. In a typical prior art fission chamber detector system for monitoring neutron flux in a nuclear reactor, a number of fission chambers are located inside a biological shield that surrounds the reactor core. Neutron signals produced in response to the detection of neutrons are transferred over conductors, such as coaxial cables to a preamplifier unit located inside a containment vessel for the reactor. The preamplifier unit amplifies the neutron signals for enabling further transmission via coaxial cables. In prior art systems, the preamplifier units are located within the containment vessel for the nuclear reactor because in such prior art systems, the quality of the neutron signals would be so much diminished by electrical noise, attenuation, and signal reflection if the preamplifier units were located more than one hundred feet (thirty meters) from the neutron chambers that the sensitivity of the system would be impaired. The location of the preamplifier units within the containment vessel makes the preamplifier units susceptible to being rendered inoperable in the event that they are subjected to a hostile environment such as exists when the reactor suffers a loss of coolant accident. In the event of such an accident, the environment within the containment vessel is severely changed. Steam, boric acid, caustic sprays and other contaminants that are adverse to electrical circuits permeate the air, and the temperature and the air pressure increase to such an extent that preamplifier units in conventional containers would not withstand the increased temperature and would be damaged by such contaminants as penetrated the container under the conditions of increased pressure. Also the radiation level would increase to make the preamplifier units inoperative from the radiation damage. Yet, it is particularly important that neutron flux within the biological shield be monitored during and following a loss-of-coolant accident. This would require preamplifier units located within the containment vessel to be shielded from high radiation and temperature and to have containers that can withstand high pressure and be impermeable to contaminants. It is impractical and very expensive to meet this requirement. It is desirable to monitor neutron flux over an extra wide range of up to twelve decades. However, most prior art fission chamber detector systems for monitoring neutron flux have a useful range of only ten decades. A decade is the range from 10.sup.n to 10.sup.n+1. In some prior art systems for monitoring neutron flux, the range has been extended to twelve decades by using proportional counters in combination with fission chamber detectors. However, proportional counters have a relatively short lifetime and their performance is rapidly degraded by the presence of gamma rays and the high temperatures surrounding the reactor core. In processing the amplified signals to provide indications of reactor power and the rate of change of reactor power, the system utilizes pulse counting for the lower portion of the monitored range and a mean square voltage processing technique for the upper portion of the monitored range. In prior art systems difficulties have been encountered in aligning the pulse count signals with the mean square voltage signals. Heretofore, it has not been possible to obtain an accurate alignment with a simple calibration system, and it has been necessary to use a nuclear reactor in adjusting the alignment. A particularly difficult problem in signal alignment that arises in prior art monitoring systems, such as described in U.S. Pat. No. 3,579,127 to Thomas, is the presence of spurious transients in processed signals indicating the rate of change of reactor power. These transients are caused during the transitions between the pulse count signals and the mean square voltage signals. To minimize this problem, prior art monitoring systems make use of complex bias and alignment circuitry and require expensive time consuming alignment procedures. SUMMARY OF THE INVENTION The present invention is a fission chamber detector system for monitoring neutron flux in a nuclear reactor over an extra wide range, with high sensitivity in a hostile environment. The coaxial cables that are used for conducting neutron signal pulses from the fission chamber detectors to a preamplifier and signal conditioning unit are uniquely constructed to enable the preamplifier and signal conditioning unit to be located outside of the containment vessel without significantly diminishing the quality of the neutron signals. Each of these coaxial cables includes a center conductor; a coaxial high temperature insulating layer closely covering the center conductor; a coaxial dielectric layer closely covering the insulating layer, the dielectric layer being resistant to damage caused by nuclear radiation; a coaxial conductive solid sheath layer closely covering the dielectric layer; and a coaxial outer insulating layer, said outer layer being resistant to nuclear radiation damage. Preferably, the sheath layer is copper tubing. The solid sheath is tightly sealed to a coaxial connector to protect the respective interiors of the cable and connector from potentially destructive contaminants under high pressure. To reduce attenuation and to increase noise immunity in the coaxial cable, the center conductor and the solid sheath layer have low resistance. Signal reflection in the cable is reduced by terminating each coaxial cable at the preamplifier unit by an impedance that matches the characteristic impedance of the coaxial cable. With the preamplifier and signal conditioning unit located outside of the containment vessel, transmission of the amplified and conditioned signals from the preamplifier and signal conditioning unit can be accomplished by twisted shield pairs rather than by more expensive coaxial cables as is done in prior art systems. This is possible because of the nature of the signal conditioning that is accomplished in the preamplifier and signal conditioning unit of this invention. Although the coaxial cable is constructed to withstand the adverse effects of a hostile environment, such as would occur in the event of a loss-of-coolant accident, a double barrier against such adverse effects is provided by using a metal hose, junction boxes and a container for the fission chambers to cover the coaxial cables and fission chambers within the containment vessel. This barrier protects the cable and connectors from potentially dangerous contaminants under high pressure and further shields out electromagnetic radiation to reduce electrical noise. In another aspect of the present invention, power indication signals obtained by a pulse counting technique for a lower reactor power range and power indication signals obtained by a mean square voltage processing technique for a higher overlapping reactor power range are accurately aligned for providing indications by a single display device. In this aspect of the invention, amplified neutron signal pulses from a fission chamber detector are (1) separately conditioned by a threshold detector and processed by a countrate circuit to provide a first power signal that is representative of power in the lower reactor power range; and (2) conditioned to provide a conditioned signal that is proportional to the square root of reactor power and then processed by a mean square voltage circuit to provide a second power signal that is representative of power in the higher reactor power range. The region of overlap of the higher and lower power ranges is determined by circuit noise, which defines the lower limit of the higher power range and by countrate loss at the power level at which the pulses counted by the countrate circuit occur at such frequency as to become indistinguishable, which defines the upper limit of the lower power range. A voltage-controlled switch is coupled to the countrate circuit and to the mean square voltage circuit for passing the first power signal onto a first output line when the second power signal is less than a predetermined voltage that is representative of a reactor power level below the power level at which the counted pulses in the first pulsed signal become indistinguishable, and for passing the second power signal onto the first output line when the second power signal level is equal to or exceeds that predetermined voltage. To obtain indications of the rate of change of reactor power, the first and second power signals are differentiated to provide respective first and second rate-of-change signals. A slave switch is connected to the differentiators and coupled to the voltage-controlled switch for passing the first rate-of-change signal onto a second output line when the voltage-controlled switch passes the first power signal onto the first output line, and for passing the second rate-of-change signal onto the second output line when the voltage-controlled switch passes the second power signal onto the first output line. The first and second rate-of-change signals are accurately aligned without incurring spurious transients. A power signal and a rate-of-change-of-reactor-power signal for a low range of reactor power that is applicable during reactor start-up are derived from very sensitive threshold detectors in the preamplifier and signal conditioning unit and by a separate countrate circuit. These are used with the aligned power signals and rate-of-change-of-reactor-power signals derived as described above to enable neutron flux to be monitored over a range of up to twelve decades. In still another aspect of the present invention, the preamplifier and signal conditioning unit includes at least one preamplifier having an input stage that includes a semiconductor switching device having a gate terminal, an input terminal coupled to the coaxial cable for receiving neutron signal pulses from the fission chamber, and an output terminal coupled to an amplifier stage for providing the received neutron signal pulses to an amplifier stage in the preamplifier when the switching device is rendered conductive; and a control circuit connected to the switching device and having a control terminal for rendering the switching device conductive when a first predetermined voltage is applied to the control terminal and for inhibiting conduction by the switching device when a different second predetermined voltage is applied to the control terminal. The control circuit includes a conduction path from the control terminal to the amplifier stage. In accordance with this aspect of the invention, a test signal generator is connected to the control terminal of the input stage for providing a test signal having a voltage level equal to or exceeding the second predetermined voltage for thereby inhibiting the semiconductor switching device from conducting and for providing the test signal to the amplifier stage for testing the operation of the monitoring system. Test signals can thereby be inserted for calibrating the monitoring system without the use of an electro-mechanical switch in the preamplifier and signal conditioning unit. Additional features of the present invention are described in the description of the preferred embodiment.
062140868	claims	1. Apparatus for the simultaneous discharge of particulate hot direct reduced iron (DRI) and particulate cold DRI from a continuous supply of hot DRI, comprising: a furnace discharge section for receiving and discharging hot DRI, a first discharge conduit and a second discharge conduit connected to said discharge section; a particle cooler, said first discharge conduit communicating with said particle cooler; a vessel for receiving hot particulates, said second discharge conduit communicating with said vessel. providing a continuous supply of hot DRI; gravitationally conveying a first portion of said hot DRI hermetically through a first seal leg to a hot DRI receiving vessel; gravitationally conveying a second portion of said hot DRI hermetically to a hot DRI cooling vessel and forming cooled DRI product; discharging said cooled DRI product; and discharging said hot DRI from said vessel for transport, briquetting, or melting. 2. Apparatus according to claim 1, further comprising a plurality of burden feeders within said furnace discharge section for conveying DRI material through said discharge section to said discharge conduits. 3. Apparatus according to claim 1 wherein said first discharge conduit is a dynamic seal leg. 4. Apparatus according to claim 1 wherein the vessel for receiving hot particulates is a surge vessel which communicates with the hot discharge conduit through a vertical feed means. 5. Apparatus according to claim 4 wherein the feed means is a feed screw. 6. Apparatus according to claim 1 wherein the second discharge conduit is a dynamic seal leg. 7. Apparatus according to claim 6 further comprising means for degassing and depressurizing hot DRI in said second conduit. 8. Apparatus according to claim 1 wherein said particle cooler is provided with a discharge control mechanism. 9. Apparatus according to claim 8 wherein said discharge control mechanism is a vibratory feeder. 10. A method for the simultaneous discharge of hot direct reduced iron (DRI) material and cold DRI material from a continuous supply of hot DRI, comprising:
	claims	1. A defect repair apparatus for an EUV mask that repairs a defect in the EUV mask using a hydrogen ion beam, comprising:a gas field ion source that generates a hydrogen ion beam, the gas field ion source having an emitter with a pointed tip end that emits hydrogen ions that form the hydrogen ion beam;an ion optical system that focuses the hydrogen ion beam onto the EUV mask;a sample stage on which to place the EUV mask;a detector that detects secondary charged-particles generated from the EUV mask; andan image forming unit that forms an observation image of the EUV mask on the basis, of an output signal from the detector. 2. The defect repair apparatus for an EUV mask according to claim 1; further comprising:a hydrogen gas supply source that supplies hydrogen gas to the gas field ion source; anda purifier that is provided between the gas field ion source and the hydrogen gas supply source and purifies the hydrogen gas. 3. The defect repair apparatus for an EUV mask according to claim 1; further comprising:an ion generation chamber in which the hydrogen ion beam is generated;a vacuum sample chamber that accommodates the sample stage; andan intermediate chamber provided between the ion generation chamber and the vacuum sample chamber. 4. The defect repair apparatus for an EUV mask according to claim 1; wherein the gas field ion source and the ion optical system irradiate the hydrogen ion beam having a beam diameter of 5 nm or less onto the EUV mask. 5. The defect repair apparatus for an EUV mask according to claim 1; wherein an upper limit value of an amount of irradiation of the hydrogen ion beam onto the EUV mask is 4×1016 ions/cm2. 6. The defect repair apparatus for an EUV mask according to claim 1; further comprising a current measuring electrode that is provided between the gas field ion source and a focusing lens electrode of the ion optical system and measures an amount of current of the hydrogen ion beam. 7. The defect repair apparatus for an EUV mask according to claim 1; further comprising a deposition gas supply system that supplies a deposition gas to the EUV mask. 8. The defect repair apparatus for an EUV mask according to claim 1; further comprising an etching gas supply system that supplies an etching gas to the EUV mask. 9. A defect repair method for an EUV mask for repairing a defect in the EUV mask using a hydrogen ion beam, comprising:generating a hydrogen ion beam using a gas field ion source having an emitter with a pointed tip end that emits hydrogen ions;obtaining an observation image of a region of the EUV mask by scanning and irradiating the hydrogen ion beam onto the EUV mask;setting a defect repair position of a defect in the EUV mask from the observation image; andrepairing the defect by irradiating the hydrogen ion beam to the defect repair position. 10. The defect repair method for an EUV mask according to claim 9; wherein an upper limit value of an amount of irradiation of the hydrogen ion beam onto the EUV mask is 4×1016 ions/cm2. 11. The defect repair method for an EUV mask according to claim 9; further comprising supplying a deposition gas to the defect while the defect is being irradiated with the hydrogen ion beam to repair the defect. 12. The defect repair method for an EUV mask according to claim 9; further comprising supplying an etching gas to the defect while the defect is being irradiated with the hydrogen ion beam to repair the defect. 13. The defect repair method for an EUV mask according to claim 9; wherein the EUV mask comprises a reflection layer, and an absorption layer pattern provided on the reflection layer; and wherein the repairing of the defect comprises repairing a defect in the absorption layer pattern while irradiating the defect with the hydrogen ion beam. 14. The defect repair method for an EUV mask according to claim 13; wherein irradiating the defect with the hydrogen ion beam is performed without causing substantial deterioration in reflectance of the reflection layer. 15. The defect repair method for an EUV mask according to claim 13; wherein an upper limit value of an amount of irradiation of the hydrogen ion beam onto the EUV mask is 4×1016 ions/cm2. 16. A defect repair apparatus for repairing a defect in an EUV (Extreme Ultra Violet) mask, comprising:an ion beam column that scans and irradiates an EUV mask with a focused hydrogen ion beam such that no region of the EUV mask receives an amount of beam irradiation exceeding 4×1016 ions/cm2, the ion beam column comprising a gas field ion source having an emitter with a pointed tip end that emits hydrogen ions that form the hydrogen ion beam, and an ion optical system that focuses and scans the hydrogen ion beam onto the EUV mask;a detector that detects secondary charged particles generated from the EUV mask when irradiated with the hydrogen ion beam; andan image forming section that forms and displays an observation image of the EUV mask on the basis of an output signal from the detector so that a defect in the EUV mask and the progress of the defect repair can be observed. 17. A defect repair apparatus according to claim 16; wherein the ion beam column is configured to generate a focused hydrogen ion beam having a beam diameter of 5 nm or smaller. 18. A defect repair apparatus according to claim 16; further comprising a sample chamber in which is disposed a sample stage for supporting the EUV mask and into which extends the ion beam column; and wherein the ion beam column includes an ion generation chamber containing the gas field ion source, an intermediate chamber disposed between the sample chamber and the ion generation chamber and through which the hydrogen ion beam passes from the ion generation chamber to the sample chamber, and means for evacuating the intermediate chamber separately from the ion generation chamber. 19. A defect repair apparatus according to claim 16; further comprising a hydrogen gas supply source that supplies hydrogen gas to the gas field ion source; and at least one purifier that is provided between the gas field ion source and the hydrogen gas supply source and that purifies the hydrogen gas. 20. A defect repair apparatus according to claim 19; wherein the at least one purifier comprises two purifiers connected in series. 21. A defect repair apparatus according to claim 16; further comprising a deposition gas supply system that supplies a deposition gas to the EUV mask while the EUV mask is being irradiated with the hydrogen ion beam to repair a missing defect in the EUV mask. 22. A defect repair apparatus according to claim 16; further comprising an etching gas supply system that supplies an etching gas to the EUV mask while the EUV mask is being irradiated with the hydrogen ion beam to repair a redundant defect in the EUV mask. 23. A defect repair apparatus, according to claim 16; further comprising a current measuring electrode that is provided between the gas field ion source and a focusing lens electrode of the ion optical system and that measures an amount of current of the hydrogen ion beam.

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