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043057861	summary	BACKGROUND OF THE INVENTION As is known, nuclear reactors consist of an array of fuel rods containing the nuclear fuel. The fuel rods are metal tubes, typically from 8 to 15 feet in length and about 1/2 inch in diameter, and are supported in groups of fuel assemblies which may comprise a considerable number of rods. The large reactors utilized for power generation contain a large number of these fuel assemblies arranged in a suitable configuration. After an extended period of operation, the irradiated or spent fuel assemblies must be removed from the reactor and replaced. The spent fuel rods contain residual amounts of the original fuel material, and various amount of numerous fission products resulting from fission of the nuclei of the original fuel. Other nuclear reactions within the reactor transmute some of the elements present into new materials. Certain of these materials are themselves fissionable. Many of the fission products and new elements are highly radioactive, at least initially, and thus produce considerable heat and the entire fuel assembly is dangerously radioactive. The fuel rods can be reprocessed by chemically separating the fissionable material for reuse as fuel and recovering the various other fission products, or the fuel assemblies may be disposed of by placing them in permanent storage, or otherwise. When radioactive fuel elements of the type described above are discharged from a nuclear reactor, they are normally stored, at least initially, in a water-filled pool which serves two purposes. The first of these purposes is to permit a cooling period to occur so that the radioactivity of the fuel assemblies may decline and they can be more easily handled. Secondly, the pool forms a convenient temporary storage place for the elements until some permanent disposal means such as reprocessing is employed. Because of the cost of storage facilities for spent nuclear fuel assemblies, it is desirable to store as many elements as practical in the pool; and elaborate racks have been devised to permit close physical packing of these elements. The limiting factor in the number of fuel assemblies contained in a pool is the fact that the used fuel elements still contain fissionable materials as explained above; and if a given number of elements having a sufficient fissionable material content is placed together in certain configurations, the possibility exists that a self-sustaining neutron chain reaction (i.e., criticality) might be set up in the pool. It is, therefore, desirable to have available some form of instrumentation capable of monitoring the neutron multiplication in the pool to insure that criticality does not occur. As fuel assemblies are added or moved around within the pool, care must be taken that a neutron multiplication factor does not approach unity too closely. (A multiplication factor of 1 is called a critical condition and is that condition of the self-sustaining neutron chain reaction). The mutiplication factor (k) may be measured directly or the departure from criticality, loosely (k-1), which is called the reactivity, may be measured. Hence, the term shutdown reactivity meter is often employed as a generic name of such devices. In the past, shutdown reactivity meters have been used principally in reactors that are capable of deliberately going critical. In particular, the critical point is usually used as a reference point in the calibration of the instrument. Two such devices have been prominently mentioned in the literature. The first of these consists of a neutron detector that is coupled to an analog or digital computer which solves the kinetic equations describing the physical behavior of reactors. One such device, for example, is described in an article by G. S. Stubbs entitled "Design and Use of the Reactivity Computer", IRE Transactions on Nuclear Science, March 1957. A reactivity metering system of this type can be operated in critical, subcritical (i.e., k less than unity) or supercritical (i.e., k greater than unity) modes but depends on dynamic signals from a neutron detector which can be calibrated at zero reactivity. A system of this sort is primarily used in large test or power reactors to measure control rod calibrations and shutdown reactivity. In its described form, it is not particularly suited to a potential reactor without control rods that presumably does not reach criticality. The second type of shutdown reactivity meter operates on neutron noise signals from a detector monitoring the neutron power level in the reactor. One such meter, for example, is described in an article by M. A. Schultz, Applicant herein, entitled "Measurement of Shutdown Reactivity in Large Gamma Fields", Neutron Noise, Waves and Pulse Propagation, R. Uhrig, Ed, USAC Publication, May 1967. In this type of reactivity meter, the neutron noise signals are analyzed for frequency content; and from this information the transfer function, and hence the shutdown reactivity, can be inferred. Again, it is essential that the critical configuration transfer function be confirmed for the meter to be accurate. In addition, large efficient neutron detectors placed as closely as possible to the reactor must be used to obtain useful noise information. Furthermore, neither of the two above-described prior art systems are capable of reading multiplication factors below about 0.9. SUMMARY OF THE INVENTION In accordance with the present invention, radioactive neutron-emitting fuel elements are placed in succession in a liquid-filled tank wherein the addition of each successive fuel element will cause the aforesaid multiplication factor, k, to approach the critical value of unity in accordance with the equation: EQU CR.sub.2 /CR.sub.1 =(.alpha..sub.2 /.alpha..sub.1).(1-k.sub.1)/(1-k.sub.2) In the foregoing equation, CR.sub.1 is the neutron counting rate determined by a neutron counter before a successive fuel element is added or is an initial reference counting rate, CR.sub.2 is the neutron counting rate determined by the neutron counter after the successive fuel element or elements are added, .alpha..sub.2 /.alpha..sub.1 is a correction factor dependent upon the geometry of the liquid-filled tank and the positioning of the successive fuel element in relation to fuel elements already in the tank, k.sub.1 is the multiplication factor which exists before the successive fuel element is added to the tank in accordance with the equation: EQU CR.sub.1 =.alpha..sub.1 S/(1-k.sub.1) where S is the emission rate of neutrons in the tank either from the fuel elements themselves or from a deliberate neutron source placed in the tank, and k.sub.2 is the multiplication factor which exists after the successive fuel element is added to the tank in accordance with the equation: EQU CR.sub.2 =.alpha..sub.2 S/(1-k.sub.2) In carrying out the invention, the multiplication factor, k.sub.2, is determined after each successive fuel element is added to the tank to determine whether criticality exists (i.e., whether k.sub.2 is approaching unity). This is achieved by providing some form of neutron source in the tank and a neutron detector spaced from the source, together with computer means for electrical signals indicative of the quantities CR derived from the detector before and after each successive fuel element is added to the tank. The computer also includes memory means for storing a value indicative of .alpha..sub.2 /.alpha..sub.1 for each element added to the tank based upon a given geometric positioning of fuel cells already in the tank. Finally, the computer includes means for computing the quantity k.sub.2 after the insertion of each successive fuel element in the tank from the foregoing equation: EQU CR.sub.2 /CR.sub.1 =(.alpha..sub.2 /.alpha..sub.1).(1-k.sub.1)/(1-k.sub.2) wherein k.sub.1 is the stored value of the multiplication factor computed for the fuel element inserted into the tank before the aforesaid successive fuel element.
	description	This application is a division of U.S. patent application Ser. No. 14/874,219, filed Oct. 2, 2015, now U.S. Pat. No. 9,728,287, the disclosure of which is expressly incorporated by reference herein in its entirety. Nuclear energy originates with a nuclear reaction within a “nuclear reactor”. A nuclear reactor typically includes a vessel defining a chamber and a core including internal components situated within the chamber. In commercial power reactors, for example, the core includes a plurality of internal components arranged to accommodate the fuel assemblies and measurement devices/probes. The nuclear reaction releases energy, transferring heat to a circulating fluid. The nuclear reactor core is the location where the chain reaction of nuclear fission occurs and generates energy. Nuclear fissions also induce irradiation of the nuclear reactor core components and thus generate various irradiated materials. For example, the inside of the vessel, as well as the reactor internal components, are considered irradiated. To comply with pertaining regulations for dismantling and decommissioning a nuclear reactor at the end of its operating life, the irradiated materials require certain procedures/processes for handling. Removal and disposal of a nuclear reactor's fuel core is not considered part of the decommissioning process because used nuclear fuel disposal is subject to a different process. However, the decommissioning of the remaining portions the nuclear reactor core, for example, the vessel and the reactor internal components, are described in the present application. Many nuclear power plants will be shut down in the coming future, whether such shutdowns are scheduled or premature. Therefore, there exists a need for a process with improved efficiency and safety for decommissioning a nuclear reactor vessel and internal components. This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This summary is not intended to identify key features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. In accordance with one embodiment of the present disclosure, a method of decommissioning a nuclear reactor including a vessel defining an inner chamber and reactor internal components positioned within the inner chamber is provided. The method includes removing at least some of the internal components; repackaging at least some of the removed internal components in at least one of the first and second predefined sections of the vessel defining a cutting zone between the at least first and second predefined sections; disposing the vessel in a container; and encapsulating the internal components in the vessel and encapsulating the vessel in the container to generate a package. In accordance with another embodiment of the present disclosure, a package including components from a decommissioned and dismantled nuclear reactor is provided. The package includes a vessel encapsulated in a container, and a plurality of components encapsulated in the vessel, wherein the nuclear components are configured to define one or more cutting zones in the vessel for cutting the package into a plurality of sections. In any of the embodiments described herein, a method may further include cutting the vessel substantially along a plane through the cutting zone to divide the package into at least two sub-packages. In any of the embodiments described herein, a method may further include affixing end caps to the sub-packages after cutting the package into sub-packages. In any of the embodiments described herein, the end caps may have a skirt. In any of the embodiments described herein, the internal components may be entirely contained within at least one of the first and second predefined sections. In any of the embodiments described herein, repackaging the internal components may include repositioning the internal components and inserting a cutting zone in the vessel. In any of the embodiments described herein, the cutting zone may include first and second dividers spaced a predetermined distance from one another to define a space therebetween. In any of the embodiments described herein, a cutting material may be disposed between the first and second dividers. In any of the embodiments described herein, defining the cutting zone may include inserting a prefabricated divider assembly including first and second dividers. In any of the embodiments described herein, defining the cutting zone may include inserting first and second dividers in the vessel, the first and second dividers spaced a predetermined distance from one another. In any of the embodiments described herein, a method may further include disposing a cutting material between the first and second dividers. In any of the embodiments described herein, a divider may act as the cutting zone. In any of the embodiments described herein, encapsulating the internal components in the vessel may include encapsulating using a first material. In any of the embodiments described herein, the first material may be selected from the group consisting of cementitious grout, epoxy grout, resin, glass, and plastic or a mix thereof. In any of the embodiments described herein, the cutting zone may include a second material as a filling material. In any of the embodiments described herein, the second material may be selected from the group consisting of cementitious grout, epoxy grout, resin, glass, and plastic or a mix thereof. In any of the embodiments described herein, the second material may be the same or different from the third material. In any of the embodiments described herein, encapsulating the vessel in the container may include encapsulating using a third material. In any of the embodiments described herein, the third material may be selected from the group consisting of cementitious grout, epoxy grout, resin, glass, and plastic or a mix thereof. In any of the embodiments described herein, the dividers may be made from a structural material. In any of the embodiments described herein, the dividers may be attached to the interior surface of the vessel. In any of the embodiments described herein, the dividers may include one or more pathways to allow the encapsulation material to pass through to adjacent sections. In any of the embodiments described herein, a method may further include repackaging and/or rearranging at least some of the internal components in at least first, second, and third predefined sections of the vessel. In any of the embodiments described herein, a method may further include packaging other irradiated components from the nuclear reactor into the vessel prior to encapsulating. In any of the embodiments described herein, selected internal components positioned within at least one of the first and second predetermined sections may remain within the vessel. In any of the embodiments described herein, the container may include exterior circumferential grooves to align with the cutting zone in the vessel. In any of the embodiments described herein, a method may further include using a diamond wire to cut the cutting zones in the vessel. In any of the embodiments described herein, a method may further include using the grooves to guide the diamond wire. In any of the embodiments described herein, the dividers may include at least two dividing plates distanced from one another to create a space therebetween. In any of the embodiments described herein, at least a portion of the cladding of the vessel interior may be removed prior to repackaging near or at the cutting zones. The detailed description set forth below in connection with the appended drawings, where like numerals reference like elements, is intended as a description of various embodiments of the disclosed subject matter and is not intended to represent the only embodiments. Each embodiment described in this disclosure is provided merely as an example or illustration and should not be construed as preferred or advantageous over other embodiments. The illustrative examples provided herein are not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. Similarly, any steps described herein may be interchangeable with other steps, or combinations of steps, in order to achieve the same or substantially similar result. In the following description, numerous specific details are set forth in order to provide a thorough understanding of exemplary embodiments of the present disclosure. It will be apparent to one skilled in the art, however, that many embodiments of the present disclosure may be practiced without some or all of the specific details. In some instances, well-known process steps have not been described in detail in order not to unnecessarily obscure various aspects of the present disclosure. Further, it will be appreciated that embodiments of the present disclosure may employ any combination of the features described herein. Embodiments of the present disclosure relate to methods for decommissioning and dismantling a nuclear reactor core. In accordance with methods described herein, an optimized segmentation method can be used for decommissioning nuclear core components, for example, the reactor vessel and internal components. In previously developed decommissioning methods, a “one-piece” decommissioning method has been used. The method typically includes removing the Greater-Than-Class-C (GTCC) components from the reactor vessel internal components and loading the GTCC components in storage canisters typically stored in a dry used fuel storage facility known as an Independent Spent Fuel Storage Installation (ISFSI). The remaining reactor vessel internal components are then encapsulated inside the reactor vessel, for example in a cementitious grout. The resulting package is then encapsulated in a container and shipped in one piece to the disposal site. In another previously developed method, a “full segmentation” method includes segmenting all of the reactor vessel internal components and the vessel itself into pieces to be packaged in standardized containers, shipped, and disposed of at a disposal site. Such a process is described in U.S. Pat. No. 5,297,182, issued to Cepkauskas. The “one-piece” method has many advantages over the “full segmentation” method, including reducing the amount of work required inside the reactor or containment building, the radioactivity dose to workers, and the impact on the general population by shipping a limited number of radioactive waste shipments. However, the one-piece approach may not be feasible for larger commercial nuclear power plants given the locations and available transportation methods associated with current licensed disposal sites. For example, the one-piece method was efficient and cost effective to decommission the 60 megawatt reactor at the Shippingport Power Plant. The Shippingport reactor core was successfully shipped offsite in one-piece in December 1988. Given the restrictions on accessing disposal sites for larger reactors in use today, the nuclear decommissioning industry has moved toward the full segmentation approach to decommission the larger-scale nuclear reactor core components. In accordance with embodiment of the present disclosure, the “Optimized Segmentation” method as described herein presents a hybrid approach of the “one-piece” and “full segmentation” methods and considers the constraints of decommissioning large nuclear reactor core components. Referring to FIG. 1, an “Optimized Segmentation” method includes obtaining a reactor vessel 20 in an underwater pool, the reactor vessel 20 including internal components 22. The vessel 20 includes a body 24 and a top closure head 26. Referring to FIG. 2, removing the top closure head 26 provides access to the inner chamber 28 of the vessel 20, from which internal components 22 can be removed. When the internal components 22 have been removed, inner cladding and/or a portion of the inner wall material on the inner surface of the vessel 20 may be removed to accommodate a low radioactivity cut zone through the vessel 20 using segmentation technology, such as a diamond wire, as described in greater detail below. It should be appreciated that removal of the inner cladding may include removal of only a portion of the inner cladding, for example, removal of the inner cladding at or near the cutting zone 46 of the vessel 20, as described in greater detail below. The removal of the inner cladding at or near the cutting zone 46 aids in the cutting of the wall of the vessel 20. Removal of part or all of the reactor vessel inner cladding and/or reactor vessel shell may be performed using one or more different techniques, such as milling, sandblasting, high pressure water, etc. An abrasive water jet may be used to remove the cladding or shell material when positioned at the adequate distance away from the material to be removed and using a special end effector tool. The target removal areas and removal depth depend on the optimization pattern parameters. The repackaged internal components 22 may fall under different classifications within the regulations for disposal of radioactive waste. Each package must meet the disposal site's acceptance criteria and license requirements. These requirements may require removal of some internal components to meet the criteria, such as curie limitations. After the internal components are removed from the reactor vessel, internal components can be segmented, when necessary, using a technology such as abrasive water jet. Referring to FIG. 3, the internal components 22 are rearranged and reinserted into the vessel 20 using dividers 30 to create a plurality of sections 40, 42, 44 inside the vessel 20 and also to create a space region 32 between adjacent sections 40, 42, and 44. In the illustrated embodiment, the internal components 22 are rearranged into three sections 40, 42, and 44. However, it should be appreciated that any other plurality of sections is within the scope of the present disclosure. In accordance with embodiments of the present disclosure, at least some of the internal components 22 are rearranged and repackaged into the vessel 20. In one embodiment, all or substantially all of the internal components 22 may be rearranged and repackaged in the vessel 20. Alternatively or in addition, some of the original internal components 22 can be left in the vessel 20 in a predetermined section 40, 42, or 44. Alternatively or in addition, other components which are not internal components to the vessel 20, such as nozzles, insulation, instrumentation, and secondary waste, can also be inserted into the vessel 20 prior to encapsulation. Dividing sections 42 and 44 is a space region 32 between sections 42 and 44 defining an unencumbered cutting zone 46. An unencumbered cutting zone 46 refers to a cutting zone free or substantially free of highly irradiated radioactive material. Spacing the compartmented internal components 22 as described in this patent is one example of a method to create an unencumbered cutting zone 46. Embodiments of the present disclosure are directed to systems and methods for creating compartments inside the vessel 20 for the purpose of creating an unencumbered cutting zone 46. As a non-limiting example and depending on the cutting technology parameters and accuracy, a suitable thickness for the unencumbered cutting zone 46 may be in the range of about 6 inches to about 12 inches. The space region 32 may be empty or may be filled with a suitable material 54, such as grout. In the illustrated embodiment, two dividers 30 are positioned adjacent each other to create a space region 32 between the adjacent dividers 30. The dividers 30 may be designed to provide appropriate shielding in the cutting zone 46 after the sections 40, 42, and 44 have been cut (see FIG. 10). Therefore, the dividers 30 may be designed with considerations for relevant material and thickness for shielding purposes. In one embodiment of the present disclosure, the dividers 30 may be metal plates, such as alloys of steel, lead, nickel, or other metals. The dividers 30 may also include neutron absorbing materials. In other embodiments of the present disclosure, the dividers 30 may be other non-metal structural materials, such as plastic or another inorganic material. The dividers 30 may be discrete plates or may be an assembly of multiple parts. As a non-limiting example of multiple parts, the dividers 30 may include several angled sections or any variation/configuration of material that would result in creating an unencumbered area for the purpose of enhancing the segmentation ease and performance. As another non-limiting example of multiple parts, the dividers 30 may be created by a set of rods that that create a space region 32 between two sections, for example, between sections 40 and 42. The dividers 30 may be attached to the interior surface of the vessel 20. In that regard, the dividers may be welded, fastened, or otherwise affixed to the interior surface of the vessel 20. In another embodiment, the dividers 30 are not affixed to the interior surface of the vessel 20 prior to encapsulation. A suitable thickness for the dividers 30 may be in the range of about 1 inch to about 6 inches depending on the radioactivity of the components. The dividers 30 may be sized based on a neutron activation analysis of the specific nuclear reactor core of the nuclear power plant that is undergoing decommissioning activities. The dividers 30 are used to separate the internal components 22 in the vessel 20. In the illustrated embodiment, the internal components 22 are reconfigured in a “smart” configuration, which may facilitate the cutting of the overall package (see FIG. 9), and the transportation and disposal of the sub-packages (see FIG. 10). In that regard, the internal components 22 are reconfigured from their original configuration (see FIG. 1) to a smart configuration (see FIG. 3) to avoid cutting through any internal components 22 when cutting is performed (see FIG. 9). In that regard, the internal components 22 are entirely contained within the predetermined sections 40, 42, 44. The dividers 30 may be designed to work by pairs, each pair of dividers delimiting space region 32 forming a cutting zone 46 between the pair of dividers 30. Alternatively, a divider may be a prefabricated element having a sufficient thickness to form a cutting zone as such before installation into the vessel 20. It can be pre-filled with a filling material before installation in the vessel 20 or it can be filled with an encapsulation material after installation in the vessel 20. Referring to FIG. 3, the internal components 22 may be rearranged and reinserted into the vessel 20 in a manner to create optimized sections considering constraints on dimension, weight, and waste classification. Although the nuclear reactor core design is an important aspect in understanding and planning the segmentation phase of the large package, a variety of reactor designs exist. Therefore, an optimization pattern will vary depending on the nuclear power plant. Such optimization can lead to reducing the overall nuclear reactor core decommissioning costs (including package, transportation, and disposal costs). Referring to FIG. 4, with at least some of the internal components 22 rearranged and reinserted in the vessel 20, the vessel 20 can be encapsulated with an encapsulation material 54. Prior to encapsulation, adequate preparation of the reactor vessel 20 may be required, for example, attaching metal plates 50 and 52 to the vessel 20 top opening and to inner or outer ends of severed nozzles. An encapsulation delivery system allows encapsulation of the internal components 22 within each vessel section 40, 42, and 44 and any other open space in the vessel 20. In one non-limiting example, hoses may be used to deliver encapsulation material 54 to each section 40, 42, and 44 and to space region 32, after cutting zones 46 have been set. As another non-limiting example, the dividers 30 or cutting zone 46 can be fabricated with holes or pathways to allow for the encapsulation material to pass through the dividers (see, for example, FIGS. 5A-5C). The dividers 130, 230, 330 shown in respective FIGS. 5A-5C have holes for enabling the encapsulating material to flow through them. The holes are designed to prevent direct exposition to radiation or “shine”. The holes may take any appropriate shape to achieve the prevention of exposition to direct radiation, such as for example a dog-leg shape (FIG. 5C), a wave shape (FIG. 5B), or more simply and inclined shape (FIG. 5A). Alternatively, the dividers 30 can be omitted provided that the internal components 22 are attached to the vessel prior to encapsulation in such a way that distinct groups or sections of internal components 22 are formed, leaving free space between the sections forming unencumbered cutting zones 46. During the encapsulation process for the sections 40, 42, and 44, the space region 32 between sections 42 and 44 and 40 and 42 forming an unencumbered cutting zone 46 also may be encapsulated. Suitable encapsulation materials, such as grout, may be used to fill the sections 40, 42, and 44 of the vessel 20. Likewise, suitable encapsulation materials, such as grout made of cementitious or epoxy material, may be used to fill the space region 32 between sections 42 and 44 and 40 and 42. Different kinds of encapsulation materials may be used for different performance characteristics. For example, one type of grout may be advantageous for holding the internal components together in the vessel 20. Another type of material, such as low density grout may be advantageous for cutting. Suitable encapsulation materials include but are not limited to cementitious or epoxy grout, resin, glass, plastic, etc. Referring to FIGS. 6B-7B, after the vessel 20 has been repackaged with unencumbered cut zones and encapsulated, the resulting vessel 20 is inserted into a container 60 for further encapsulation with encapsulation material 56. In the illustrated embodiment, the container 60 is cylindrical having a circular cross-section. However, in other embodiments of the present disclosure, the container 60 may have another cross-sectional shape, including but not limited to square or hexagonal cross-sections. Referring to FIG. 6A, the vessel 20 is lifted into the container 60. In the illustrated embodiment, the container 60 is in the cavity with water. However, if the vessel 20 has been encapsulated and radioactively protected, this step may be performed as a dry step. The container 60 may include a top portion 66, or the top portion may be added after the vessel 20 has been lifted into the container 60. After the vessel 20 has been positioned in the container 60, a bottom plate (not shown) can be welded, fastened, or otherwise attached to the container 60. Referring to FIGS. 7A and 7B, an alternate method is provided. The container 60 is dropped to the bottom of the reactor cavity. The vessel 20 is lifted and placed into the container 60 (which already includes a bottom portion 64). Referring to FIG. 8, after the vessel 20 is received in the container 60, the vessel 20 is encapsulated inside the container 60. Different or similar encapsulation materials 58, such as grout, may be used to fill the container 60 as used to fill the space regions 32 and sections 40, 42, and 44. Referring to FIG. 9, after encapsulation of the container 60, the package 68 can be segmented using a suitable segmentation technology, such as diamond wire cutting, to segment the whole package into transportable segments. Grooves 62 on the outer surface of the container 60 correspond with cutting zones 46 to provide alignment and positioning of the cutting means during the segmentation process of the package. The grooves 62 can be used for one or more non-limiting purposes: controlling segmentation path, aligning cutting equipment, cutting in the unencumbered cut zone. The grooves 62 can be machined on-site after repackaging the internal components 22 into the vessel 20 to ensure the correct location to the cutting zones 46. For example, the grooves 62 could be machined by mechanical saw. Alternatively, the grooves 62 can be prefabricated during the manufacturing of the container 60. Referring to FIG. 10, after cutting, the cut segments 80, 82, and 84 of the package 68 will be sealed with material, such as end caps 86, attached to the cutting surfaces for the purpose of creating independent transportable packages compliant with relevant regulations. End caps 86 close the cut segments 80, 82, and 84 and provide radiological shielding to meet Nuclear Regulatory Commission transport requirements. End caps 86 can be installed on the free ends of the package before or after cutting. As an example, segments 80, 82, and 84 could be disc sections sealed with end caps 86 welded to the container cut edge. The segments 80, 82, and 84 can then be transported via road, rail, or barge to a licensed disposal site. The end caps 86, like the dividers 30, may be formed from metal, such as alloys of steel, lead, nickel, or other metals. The end caps 86 may also include neutron absorbing materials. In other embodiments of the present disclosure, the end caps 86 may be other non-metal structural materials, such as plastic or another inorganic material. The end cap 86 may be designed and configured to include a skirt or similar feature that will allow for the end cap 86 to be installed and aligned, and to correct an uneven segmentation line. This design feature will maintain segment package integrity to comply with relevant regulation for such packages. Accordingly, embodiments of the present disclosure are directed to whole package design including all the features which allow for the best decommissioning approach of removing the vessel 20 and internal components 22. The engineered package can be designed to allow for as many segments as needed for specific problem areas. Also, the design will accommodate the diamond wire cutting device to reduce the dose concerns and high secondary waste classifications. In another embodiment of the present disclosure, a diamond wire cleaning chamber is provided. The wire will run through a cleaning chamber containing one or more water jet nozzles for ejecting pressurized water on the wire in different angles. The 360 degree wire cleaning effect will be supported by water reflections from the chamber walls opposite the nozzle. The nozzle may contain a concave shaped inlay to focus the reflections. Brushes (e.g., ring shaped brushes) clean the wire from water and residue before leaving the chamber. The flow of removed material and water can be supported by either installing the device in an angle or designing the lower part of the chamber (below or around the concave inlay) as a labyrinth guided into a potentially vacuuming disposal tube that provides low pressure to prevent the excessive emission of contaminated water mist. For cleaning purposes, the nozzle/brush part can be designed as an independent unit mounted and sealing to the initially top-open chamber. The principles, representative embodiments, and modes of operation of the present disclosure have been described in the foregoing description. However, aspects of the present disclosure which are intended to be protected are not to be construed as limited to the particular embodiments disclosed. Further, the embodiments described herein are to be regarded as illustrative rather than restrictive. It will be appreciated that variations and changes may be made by others, and equivalents employed, without departing from the spirit of the present disclosure. Accordingly, it is expressly intended that all such variations, changes, and equivalents fall within the spirit and scope of the present disclosure, as claimed.
053012151	abstract	A reactor building for enclosing a nuclear reactor includes a containment vessel having a wetwell disposed therein. The wetwell includes inner and outer walls, a floor, and a roof defining a wetwell pool and a suppression chamber disposed thereabove. The wetwell and containment vessel define a drywell surrounding the reactor. A plurality of vents are disposed in the wetwell pool in flow communication with the drywell for channeling into the wetwell pool steam released in the drywell from the reactor during a LOCA for example, for condensing the steam. A shell is disposed inside the wetwell and extends into the wetwell pool to define a dry gap devoid of wetwell water and disposed in flow communication with the suppression chamber. In a preferred embodiment, the wetwell roof is in the form of a slab disposed on spaced apart support beams which define therebetween an auxiliary chamber. The dry gap, and additionally the auxiliary chamber, provide increased volume to the suppression chamber for improving pressure margin.
	description	This invention relates to a substrate holding apparatus for use in ion implanters. In particular, the present invention relates to a substrate holding system comprising two or more substrate holders that can adopt interchangeable positions, thereby allowing one substrate holder to scan a substrate through an ion beam while substrates can be swapped on the other substrate holder. Although the present invention is not limited to the field of ion implanters, this field corresponds to a contemplated application and provides a useful context for understanding the invention. Hence there follows a description of ion implanters. Ion implanters are well known and generally conform to a common design as follows. An ion source produces a mixed beam of ions from a precursor gas or the like. Only ions of a particular species are usually required for implantation in a substrate, for example a particular dopant for implantation in a semiconductor wafer. The required ions are selected from the mixed ion beam using a mass-analysing magnet in association with a mass-resolving slit. Hence, an ion beam containing almost exclusively the required ion species emerges from the mass-resolving slit to be transported to a process chamber where the ion beam is incident on a substrate held in place in the ion beam path by a substrate holder. Often, the cross-sectional profile of the ion beam is smaller than the substrate to be implanted. For example, the ion beam may be a ribbon beam smaller than the substrate in one axial direction or a spot beam smaller than the substrate in both axial directions. In order to ensure ion implantation across the whole of the substrate, the ion beam and substrate are moved relative to one another such that the ion beam scans the entire substrate surface. This may be achieved by (a) deflecting the ion beam to scan across the substrate that is held in a fixed position, (b) mechanically moving the substrate whilst keeping the ion beam path fixed or (c) a combination of deflecting the ion beam and moving the substrate. For a spot beam, relative motion is generally effected such that the ion beam traces a raster pattern on the substrate. Our U.S. Pat. No. 6,956,223 describes an ion implanter of the general design described above. A single wafer is held in a moveable substrate holder. While some steering of the ion beam is possible, the implanter is operated such that ion beam follows a fixed path during implantation. Instead, the wafer holder is moved along two orthogonal axes to cause the ion beam to scan over the wafer following a raster pattern. The above design is particularly suitable for serial processing of wafers where a robot must unload a processed wafer before loading a new wafer to be implanted. Loading and unloading wafers between each implant causes an undesirable delay. Our U.S. Pat. No. 6,555,825 describes an ion implanter having a twin scanning arm arrangement shown in FIG. 1. Each scanning arm has a motorised hub unit A that can rotate about an axis X1 between a scanning position shown on the right and a loading position shown on the left. A hollow arm B is rotatably mounted to the hub unit at one of its ends so as to be able to turn about axis X2 to effect scanning of a wafer through an ion beam. The other end of the arm is provided with a wafer holder C. Wafer holder C can rotate about axis X3 to allow the orientation of the wafer to be varied. The construction and arrangement of each scanning arm is such that when the arm is in the loading position, it is above the axis X1 and therefore above the path of the ion beam D. This has particular significance because the wafer holder can be loaded and unloaded without any undesired effects due to the presence of the ion beam. At the same time, the hub unit can be rotated through 90° to convey the wafer holder to the scanning position where a wafer may be scanned through the path of the ion beam. As shown in dotted outline, the wafer may be moved on the arm from position P1 down through lower positions to position P2. In this ion implanter, a ribbon ion beam is used such that this movement sees the entire wafer implanted. Provision of two such scanning arms allows one scanning arm to be used to scan a wafer while the other scanning arm may be positioned for concurrent loading and unloading of wafers. Hence, as soon as an implant is complete for one wafer, another wafer is ready for implant on the other scanning arm. Such a scanning arm arrangement is not capable of producing linear raster scans. Another disadvantage of such radial scanning arrangements is the resultant non-uniform dose characteristics arising from differences in scan speed across the width of the wafer. This is because the closest edge of the wafer to the pivot scans more slowly than the outer edge, causing a higher dose on that side of the wafer. Against this background, the present invention resides in a substrate holder assembly for holding substrates to be exposed to an ion beam during implantation in an ion implanter, the substrate holder assembly comprising a base rotatable about a first axis and at least two support arms extending from the base to ends provided with substrate holders. Rotation of the base allows the substrate holders to adopt designated positions, with the at least two support arms extending from points displaced from the axis of rotation by substantially equal distances and separated by a substantially equal separation angle such that rotation of the base through the separation angle causes the support arms to move between designated positions. Thus, two or more sample holders may be provided that may be rotated to swap positions. For example, one position may correspond to a substrate scanning position and another position may correspond to a substrate loading/unloading position. Then, the substrate holder assembly may comprise a pair of support arms disposed on opposite sides of the axis of rotation of the base. When rotating the base between designated positions, one support arm moves from the scanning position to the loading position and the other support arm moves from the loading position to the scanning position. More than two support arms may be used. For example, three support arms may be used, arranged with a separation of 120°, or four support arms may be used arranged 90° apart. Clearly, the provision of three support arms leads to three designated positions and, likewise, four support arms gives four designated positions. Various processes may be performed at each designated position, e.g. unloading a substrate, loading a substrate, both unloading and loading a substrate, implanting, cleaning, etching, annealing, deposition, etc. One or more designated positions may not have associated processes, i.e. the substrate may merely be parked at this position while other substrates are processed at one or more other designated positions. Preferably, the substrate holders are each provided with a support surface for supporting the substrate aligned substantially normal to the support arm's longitudinal axis, and the at least two support arms are rotatable about their longitudinal axes. Optionally, the support surface is rotatable about its centre axis. This allows the orientation of a substrate held by the substrate holder to be varied. Preferably, the at least two support arms are moveable along their longitudinal axes such that the distance of each substrate holder from the base may be varied. This allows a substrate to be moved into and out of a beam, and to be scanned through an ion beam in this direction. The present invention also resides in an ion implanter comprising an ion source, optics operable to guide ions produced by the ion source along an ion beam path to a process chamber for implantation in a substrate, a substrate transfer mechanism, and a substrate holder assembly as described above to hold substrates in the process chamber. The at least two support arms extend substantially normal to the ion beam path. A first of the designated positions corresponds to the substrate holder being disposed to face into the ion beam. A second of the designated positions corresponds to the substrate holder being disposed to be clear of the ion beam path and to co-operate with the substrate transfer mechanism thereby allowing substrates to be placed on and removed from the substrate holder. Preferably, the at least two support arms are moveable along their longitudinal axes such that the distance of each substrate holder from the base may be varied. Optionally, the base may have an associated scanning unit that is operable to scan the support arm back and forth along its longitudinal axis. Also, the scanning unit may be operable to scan the support arm in a direction substantially normal to both the longitudinal axis of the support arm and the ion beam path. This allows a substrate to be scanned relative to a fixed ion beam, for example according to a raster pattern. Alternatively, the substrate may be held in position while an ion beam is scanned across the substrate or a hybrid system may be used where both substrate and ion beam are moved. In order to provide a context for the present invention, an exemplary application is shown in FIG. 2, although it will be appreciated that this is merely an example of an application of the present invention and is in no way limiting. FIG. 2 shows a known ion implanter 10 for implanting ions in semiconductor wafers 12. Ions are generated by the ion source 14 to be extracted and follow an ion path 34 that passes, in this embodiment, through a mass analysis stage 30. Ions of a desired mass are selected to pass through a mass-resolving slit 32 and then to strike the semiconductor wafer 12. The ion implanter 10 contains an ion source 14 for generating an ion beam of a desired species that is located within a vacuum chamber 15 evacuated by pump 24. The ion source 14 generally comprises an arc chamber 16 containing a cathode 20 located at one end thereof. The ion source 14 may be operated such that an anode is provided by the walls 18 of the arc chamber 16. The cathode 20 is heated sufficiently to generate thermal electrons. Thermal electrons emitted by the cathode 20 are attracted to the anode, the adjacent chamber walls 18 in this case. The thermal electrons ionise gas molecules as they traverse the arc chamber 16, thereby forming a plasma and generating the desired ions. The path followed by the thermal electrons may be controlled to prevent the electrons merely following the shortest path to the chamber walls 18. A magnet assembly 46 provides a magnetic field extending through the arc chamber 16 such that thermal electrons follow a spiral path along the length of the arc chamber 16 towards a counter-cathode 44 located at the opposite end of the arc chamber 16. A gas feed 22 fills the arc chamber 16 with the species to be implanted or with a precursor gas species. The arc chamber 16 is held at a reduced pressure within the vacuum chamber 15. The thermal electrons travelling through the arc chamber 16 ionise the gas molecules present in the arc chamber 16 and may also crack molecules. The ions (that may comprise a mixture of ions) created in the plasma will also contain trace amounts of contaminant ions (e.g. generated from the material of the chamber walls 18). Ions from within the arc chamber 16 are extracted through an exit aperture 28 provided in a front plate of the arc chamber 16 using a negatively-biased (relative to ground) extraction electrode 26. A potential difference is applied between the ion source 14 and the following mass analysis stage 30 by a power supply 21 to accelerate extracted ions, the ion source 14 and mass analysis stage 30 being electrically isolated from each other by an insulator (riot shown). The mixture of extracted ions are then passed through the mass analysis stage 30 so that they pass around a curved path under the influence of a magnetic field. The radius of curvature travelled by any ion is determined by its mass, charge state and energy, and the magnetic field is controlled so that, for a set beam energy, only those ions with a desired mass to charge ratio and energy exit along a path coincident with the mass-resolving slit 32. The emergent ion beam is then transported to the process chamber 40 where the target is located, i.e. the substrate wafer 12 to be implanted or a beam stop 38 when there is no wafer 12 in the target position. In other modes, the beam may also be accelerated or decelerated using a lens assembly positioned between the mass analysis stage 30 and the wafer position. The semiconductor wafer 12 is mounted on a wafer holder 36, wafers 12 being successively transferred to and from the wafer holder 36, for example through a load lock (not shown). The ion implanter 10 operates under the management of a controller, such as a suitably programmed computer 50. The computer 50 controls scanning of the wafer 12 through the ion beam 34 to effect desired scanning patterns. These scanning patterns may comprise raster scans, including interlaced patterns, as is well known in the art. FIG. 3 shows apparatus 100 for holding two wafers 102a,b in an ion implanter 10 like the one shown in FIG. 2. FIG. 4 shows the apparatus 100 in position in a process chamber 40, its sectional view corresponding to a section taken a little above the plane of the ion beam 34. As will be appreciated, the apparatus 100 is mounted to a wall 130 of the process chamber 40 and is used either to hold a wafer 102a,b in position while the ion beam 34 is scanned or to scan a wafer 102a,b through an ion beam 34. The apparatus 100 also cooperates with a robot 132 during loading and unloading of wafers 102a,b. The apparatus 100 comprises a turntable 106 that mates with a rotary actuator 134 that provides full range of rotation of the turntable 106 in the direction indicated by arrow 110. The turntable 106 is supported by a crossed-roller bearing and sealing is provided by floating air bearing labyrinth seal units with differential pumping. The rotary actuator 134 has an associated flange for mounting the apparatus to the process chamber 40. Two scanning arms 114a,b are provided, each with a wafer holder 116a,b at its end. Each scanning arm 114a,b extends from its wafer holder 116a,b back towards the supporting turntable 106, and in fact extends through the turntable 106 to be received by a linear actuator 118a,b that is mounted to the rear of the turntable 106. The scanning arms 114a,b are supported at the turntable 106 by sealed bushings 120a,b that allow the scanning arms 114a,b to be driven through the turntable 106 by the linear actuator 118a,b. In this way, the distance of the wafer holder 116a,b from the turntable 106 can be varied, i.e. the wafer 102a,b can be driven into and out of the process chamber in the direction indicated by arrow 122. In addition to driving the scanning arm 114a,b into and out of the process chamber 40, the linear actuator 118a,b also drives rotary motion of the scanning arm 114a,b such that it rotates about its longitudinal axis as indicated by the arrow 124. Each scanning arm 114a,b is hollow so as to provide routing for services to the wafer holder 116a,b. This includes a drive mechanism that allows a chuck 126a,b that supports the wafer 102a,b to be rotated about its centre, as indicated by arrow 128. The chuck 126a,b holds the wafer 102a,b firmly in place electrostatically, such that rotation of the chuck 126a,b causes corresponding rotation of the wafer 102a,b. Other methods of mounting the wafer 102a,b to the chuck 126a,b are equally possible. FIGS. 3 and 4 show the apparatus 100 with turntable 106 set so that wafer holder 116a occupies the loading position while wafer holder 116b occupies the scanning position. Rotating the turntable 106 through 180° swaps the positions occupied by the wafer holders 116a,b. In the loading position, the scanning arm 114a is rotated about direction 124 to ensure that the wafer 102a faces upwards. The electrostatic force holding wafer 102a to the chuck 126a can be interrupted and the wafer 102a removed from the chuck 126a by the robot 132. A simple robot 132 is shown in FIG. 4 that comprises a pair of hinged jaws 136 that can open and close by rotation of cam 138. Jaws 136 and cam 138 are cantilevered on an arm 140 that is mounted to shaft 142. Shaft 142 allows vertical movement (i.e. in and out of the plane of the paper) and rotation as indicated by arrow 144. Thus, the robot 132 may be rotated such that jaws 136 move over wafer 102a, the jaws 136 may be lowered on shaft 142 and closed to grip the wafer 102a. The robot 132 may then be raised on shaft 142 and subsequently rotated in direction 144 such that the wafer 102a in jaws 136 swings out of the process chamber 40 through gate valve 146. Due to vacuum considerations, a load lock is preferable to the single gate valve 146 shown in FIG. 4. The reverse procedure may then be used to load a new wafer 102a onto wafer holder 126a. As will be apparent to those skilled in the art, many other alternative robot arrangements may be used to load and unload wafers. Once a new wafer 102a is loaded onto the chuck 126a and held in place by electrostatic force, it is ready for the scanning arm 114a to be rotated. As will be appreciated from FIG. 3, the loading position sees the wafer 102a held away from the ion beam path 34. The scanning arm 114a holds the wafer 102a above the level of the ion beam path 34 and also the scanning arm 114a is retracted towards the turntable 106 along direction 122 thereby moving the wafer 102a back from the ion beam path 34. In the scanning position, the scanning arm 114b is extended away from the turntable 106 in direction 122 and is rotated in direction 124 such that the wafer 102b is held upright to face the incoming ion beam 34. In some applications, it will be preferable for the ion beam 34 to strike the wafer 102b at an angle rather than perpendicularly, for example when implanting trench walls or when using grazing angles to achieve shallower implants. This is easily accomplished by rotating the scanning arm 114b in the direction 124 such that the wafer 102b adopts the desired angle to the ion beam 34. In addition, the chuck 126b can be rotated about direction 128 to achieve a desired orientation of the wafer 102b. In this way, features on the wafer 102b such as trench walls can be correctly aligned with the ion beam 34. In this embodiment, the wafer 102b is held in the scanning position while a ribbon beam 34 is scanned across the static wafer 102b. However, other arrangements are possible. For example, a ribbon beam need not be used, and a spot beam may be scanned across the wafer 102b using a raster pattern for example. Also, the wafer 102b may be scanned in addition to or as an alternative to scanning the ion beam 34. Scanning in the x direction (taken to be the horizontal here) is readily achieved using the linear actuator 118a to drive the scanning arm 114b back and forth in the x direction. To move wafer holders 116a,b between the loading and scanning positions, three movements are required: (1) the turntable must be rotated through 180° about direction 110, either clockwise or anticlockwise as desired; (2) scanning arms 114a,b must be rotated through 90° about direction 124, scanning arm 114a in an anticlockwise direction and scanning arm 114b in a clockwise direction; and (3) scanning arms 114a,b must be moved along direction 122, scanning arm 114a into the process chamber 40 away from the turntable 106 and scanning arm 114b towards the turntable 106. Generally, these movements will be effected by the controller 50, but how it coordinates these three different movements is a matter of preference. Clearly, it is advantageous to effect the movements concurrently to avoid delay and maximise throughput of wafers 102a,b through the ion implanter 10. The scanning arms 114a,b are separated sufficiently to ensure that the wafers 102a,b cannot collide as they are rotated during movement between loading and scanning positions, even when larger 300 mm wafers are being processed. The skilled person will appreciate that changes may be made to the above-described embodiment without departing from the scope of the present invention. For example, the above embodiment exemplifies the present invention for use in the field of implanting semiconductor wafers. However, the present invention enjoys far wider applicability. For example, the present invention may be used in any type of ion implanter, whether that be for implanting semiconductor wafers or any other type of substrate. Also, the present invention may be used in any other type of apparatus that requires workpiece manipulation, where workpieces are rotated between a number of designated positions. The above embodiment describes a twin scanning arm apparatus 100. However, three or more scanning arms 114a,b may be used. Advantageously, the scanning arms 114a,b are equally spaced from the centre of rotation of the turntable such that the wafer holders 116a,b adopt the same position as they are moved between positions. Also, it is advantageous for the scanning arms 114a,b to be separated by substantially equal angles such that the scanning arms 114a,b merely rotate between successive positions. Each position may correspond to a station where a processing step is performed, e.g. implanting, loading/unloading, etching, annealing, deposition, cleaning, etc. Loading and unloading may be split into two separate actions performed at separate stations, i.e. a wafer 102a,b or other substrate is unloaded at a station before a new wafer 102a,b or other substrate is loaded at the next station. One or more positions may be idle positions where the wafer 102a,b or other substrate dwells before moving on to the next position. An idle station may be useful where limited space precludes the installation of processing apparatus adjacent that position. The embodiment of the present invention described above enjoys many degrees of movement to provide a flexible system. However, the apparatus 100 need not be provided with such capability. For example, an apparatus 100 enjoying only rotation about direction 110 to allow the scanning arms 114a,b to swap positions is possible. The loading robot would need to be adapted to load and unload wafers 102a,b from a vertical orientation, but such adaptation is straightforward. Scanning arms 114a,b need not be mobile in direction 122, i.e. towards and away from the turntable 106, because the wafer 102a,b is rotated clear of the ion beam 34. While FIG. 3 shows the scanning arms 114a,b to extend through the turntable 106, telescopic arms may be provided that do not need to penetrate the turntable 106.
044434022	description	DETAILED DESCRIPTION FIG. 1 shows a fuel rod 1 whose cladding has a fissure 2. The upper end of the rod is closed by a cap 3, with an ultrasonic generator 4 disposed in contact, producing ultrasonic waves which are propagated in the whole fuel rod from the end represented in FIG. 1 to its opposite end. The fuel rod 1 is entirely immersed in the water which fills the fuel pond. An ultrasonic sensor 5 is disposed near the lateral surface of the rod 1, connected to a vertical displacement apparatus allowing it to take up any position along the length of the rods. Z designates the displacement axis of the sensor 5 which, in the case of the apparatus represented in FIG. 1, corresponds to the vertical direction. A connection between the ultrasonic generator 4 and the sensor 5 allows the time of emission of an ultrasonic wave to be established as time origin for the sensor 5. FIG. 2 shows the signal picked up by the sensor 5 in the case of an ultrasonic wave being emitted by the generator 4. This signal S can be resolved into two signals S1 and S2. The signal S1 corresponds to the ultrasonic waves scattered at the defect 2 into the water surrounding the rod while the signal S2 corresponds to interference signals which arrive at the sensor 5 after the signal S1. In practice, when the ultrasonic wave is propagated in the cladding of the fuel rod 1, part of the energy associated with these waves is transmitted to the water surrounding the cladding in which it is propagated in the form of compression waves with a lower speed than the propatation speed of the wave in the metal of the cladding. The waves are reflected at the structures surrounding the fuel rod 1 and finally arrive at the sensor 5, which translates them into an interference signal S2. The principal signal S1 is the result of the waves which are propagated in the cladding of the rod as far as the fissure 2 where they are scattered into the water in which the rod is immersed, before arriving at the sensor 5. These scattered waves, which have a shorter path in the water than the waves reflected by the elements surrounding the rod 1, arrive at the sensor 5 before the reflected waves. In the signal registered by the sensor 5, the part S1 of the signal therefore precedes the part S2 corresponding to the interference signals. The form of the signal S1 scattered at the defect is established by calculation or measurement on an isolated rod, so that a window can be isolated, like that represented in the hatched part of FIG. 2, corresponding to the part of the ultrasonic signal scattered into the water at the defect. During displacements of the sensors 5 in the direction Z, the signal S1 is shifted in time, since the path of the scattered waves in the water varies with the position Z of the sensor 5. Accurate measurement of the position Z of the sensor 5 allows the position of the window corresponding to the signal S1 in the measured signal to be determined. The maximum amplitude of the signal S1 is then measured and the variations in this maximum amplitude as a function of the position Z of the sensor 5 along the height of the rod are determined. FIG. 3 shows the variation of this maximum amplitude as a function of the position of the sensor. It is quite clear that in the case of a defect being present in the cladding of the rod, i.e., in the case of the existence of the scattered signal S1, the curve representing the variations A (Z) has a maximum at the value Z=ZO corresponding to the position of the sensor at the exact height of the defect 2. The measuring and testing apparatus connected to the sensors 5, as shown in FIG. 1, consequently includes a preamplifier 7, a filter 8, an apparatus 9 for recording or displaying the signal A (t), after amplification and filtering, a filter 10 associated with a unit 11 for recording or displaying the window S1 of the signal filtered by the filter 10, and a unit 12 for determining the maximum amplitude A of the signal S1. The apparatus also includes a unit 14 for measuring and recording the parameter Z determining the position of the sensor 5 over the height of the rods, a signal corresponding to this value of Z being transmitted to the filter 10 to determine the window corresponding to the signal S1 as a function of the position of the sensor. Last, the apparatus includes a unit 16 for recording and/or displaying the signal A (Z) and determining the maximum of the curve A (Z). The unit 16 receives on the one hand a signal representing the instantaneous value of Z and on the other hand the value of the maximum A of the signal S1 corresponding to this value of Z. The two values are recorded and allow recording and/or display of the curve A (Z). Determination of the maximum of this curve when the sensor 5 is moved along the rod over its whole length allows determination of the value ZO corresponding to this maximum. The apparatus therefore allows, on the one hand, determination of the presence of a defect in the rod 1 during examination and on the other, determination of the exact position of this defect on the rod. In practice, the presence or absence of a scattered signal S1 in the signal picked up by the sensor 5 allows determination of a defective rod or a non-defective rod, respectively. Accurate tracing of the curve A (Z) depends on the width of the window corresponding to the signal S1 in the signal picked up by the sensor 5. Either calculating or display units can be used for the different units 9, 11 and 16, allowing determination and location of the defect by triggering of a signal associated with a numerical value, or by examination of a curve the maximum of which is determined. In the case of a non-defective rod, the signal recorded and possibly displayed by the unit 9 is characterized of interference signals, including only a part S2. The signal is easily recognizable if calibration has previously been effected on a non-defective rod in a particular way, for example a new rod, put in a comparable environment. When examination of an assembly is required, after an end plate has been removed allowing access to the end of each of the fuel rods of this assembly, a single sensor can be used, which is moved successively and automatically from one rod to another, or a set of ultrasonic emitters arranged in an array corresponding to the lattice of transverse sections of the rods in the assembly. FIG. 4 shows diagrammatically such an apparatus used for testing an assembly 20 constituted by a set of rods 21 arranged in a square-mesh lattice in a transverse plane. A set of ultrasonic emitters 22 is disposed on a plate with approximately the dimensions of the end plate of the assembly which is positioned over this so that each of the emitters 22 is over a rod 21 and in contact with its upper cap. An ultrasonic generator 23 is connected to each of the emitters 22 and associated with an electronic addressing apparatus allowing each of the emitters to be energized successively, i.e., ultrasonic waves to be sent successively into each of the rods 21 constituting the assembly. X, Y addressing, for each of the rods of the assembly, in a transverse plane with respect to the assembly allows the fuel rod in which the ultrasounds are propagated to be identified. The address of the emitter and the corresponding fuel rod is transmitted to a unit 26 which also receives the signal transmitted by a sensor 25 movable in the direction Z of the assembly, at a fixed distance from the side wall of the latter. The assembly 20 is tested while the assembly is entirely immersed in the water of the fuel pond, and the sensor 25 is constituted by a bar of unit sensors the total length of which is at least equal to the side of the square constituting the transverse section of the assembly. In this way, the value of the signal received is increased because, when work on a rod disposed inside the assembly is involved, the wave scattered into the water is reflected at the components near the rod, so that the beam emitted outside the assembly has a greater width than that of a unit sensor, generally of the order of the side of the transverse section of the assembly. The measuring and testing apparatus associated with the sensor 25 and the unit 26 is also like that described for a single fuel rod and represented in FIG. 1. This apparatus includes a preamplifier 27, a filter 28, a unit 29 for recording and displaying the signal A (t), a filter 30 receiving a signal representing the measurement Z and allowing determination of the signal S1 and its recording and/or display in the unit 31 and a unit 32 for calculating the maximum of the amplitude A of the signal A (t). This apparatus also includes a unit 34 for accurate measurement and development of a signal corresponding to the value of Z defining the position of the sensor 25 in the height dimension of the assembly and a unit 36 for recording and displaying the curve A (Z) and for determining the maximum of this curve corresponding to the value ZO defining the position of a possible defect in the rod during examination defined by its coordinates X, Y. To give the apparatus extra sensitivity, instead of a single bar disposed near one of the faces of the assembly, a set of four bars entirely surrounding this assembly can be used. The working of the apparatus represented in FIG. 4 is substantially identical to the working of the apparatus represented in FIG. 1, except that it allows identification of the defective rod or rods in an assembly by their coordinates X, Y. In practice, the coordinates X, Y can be identified at the unit 26, each time an ultrasonic signal scattered by a defect (S1) is identified on the curve A (t). If no scattered signal is found for the whole of an assembly, such assembly can be considered non-defective. One of the important advantages of the apparatus according to the invention is that it allows defective rods to be located with greater sensitivity than in prior techniques, since the signal picked up and undergoing discrimination is not drowned in the background noise of the signal produced in the rod, there being a time lag between the signal scattered by the defect and the background noise. In addition, examination can be carried out while the assembly is immersed in a protective liquid, as is always the case for irradiated assemblies during storing or moving. In addition, the detection method does not assume that the rod or the fuel assembly will be heated or that any other modification will be made in the physical conditions of the medium in which the assembly is immersed. The method according to the invention also has the advantage of allowing all the rods to be examined, even those not at the periphery of the assembly, since, with those rods disposed within the assembly, the energy scattered by the possible defect travels to the sensor after reflection on the elements adjacent to that element disposed within this assembly. In addition, the method according to the invention allows rods to be examined over their entire length and even in that part of them which is hidden by spacer grids, since the presence of the grids is translated simply into attenuation of the signal picked up which is compensated for by action on the amplitude of the signal emitted. In addition, the method according to the invention can be used on an assembly which has not been dismantled by using the free space between the caps of the rods and the upper plate for locating the sensors. The invention is not, however, limited to the embodiment described; it includes all the variants thereof. Thus, it is possible to use a fixed sensor positioned near the lateral surface of the rod or the assembly and receiving the waves which may be scattered into the water in which the rod or assembly is immersed by the defects thereof. Of course, in this case, accurate locating of the defect will not be possible, but discrimination and filtering of the signal corresponding to the scattered waves are still possible by using a sensitive enough sensor disposed at a distance from the assembly, allowing both measurement and discrimination of the signal possibly associated with waves scattered into the water. In the case of the testing of a complete assembly, instead of a bar of sensors corresponding in length to the length of the side of the assembly, a single sensor can be used, moved parallel to the side of the assembly's section so as to increase the extent of the region inspected. In this instance, the sensor is moved both parallel to the axis of the assembly and in a direction perpendicular to that axis. Use can also be made of a sensor which is moved inside guide tubes constituting the framework of the assembly instead of a sensor which is movable outside the assembly. Lastly, different ways of effecting discrimination of the signal scattered into the water in which the fuel rod or assembly is immersed from those described can be envisaged. The method and apparatus according to the invention is applicable to the detection and location of defects in any fuel assemblies constituted by fuel rods having a cladding within which the nuclear fuel is contained and which may have defects such as fissures.
047042486	summary	The present invention relates to fuel elements used in nuclear reactors and, more particularly, to a high performance fuel element including components for forming a peripheral seal and additional coolant passages aligned with, but not communicating coolant to, the sealing components. BACKGROUND OF THE INVENTION It is conventional in the nuclear reactor art, and in particular in high temperature gas cooled reactors, to provide a reactor core made up of a number of core blocks or elements which are stacked in columns. The core elements may include fuel elements and control rod elements. An example of such a fuel block or element is disclosed in U.S. Pat. No. 4,060,450 which illustrates and describes a fuel element or block comprised substantially of graphite and having generally cylindrical passages or channels therethrough for receiving fuel rods or rod segments and facilitating passage of coolant through the fuel element. Other blocks or elements are for accommodating control rods and are similar in exterior shape but generally include channels for control rods, reserve shutdown pellets or power rods which include a neutron absorbing material, such as boron carbide, and function to control operation of the reactor core. In high temperature gas cooled reactors employing prismatic fuel and control elements having generally planar end surfaces, gaps may form at the interface between stacked elements allowing coolant leakage flow into and out of the element coolant channels. Should a gap be created between adjacent fuel elements, the coolant leakage into and out of the nearest coolant channels can result in undesirable maldistribution of coolant within the fuel elements. In order to prevent or at least substantially reduce such coolant leakage, it has been proposed to provide a dependent peripheral flange on one end surface of the element and a mating recess on the other to align the coolant passages of the stacked elements and form a peripheral seal. For further information regarding the structure and operation of such fuel elements, reference may be made to U.S. Pat. No. 3,413,196, particularly to FIG. 5. The effectiveness of the seal is, in part, a function of the thickness of the flange. However, as flange thickness increases, the relative core power density decreases because a continuation of the normal fuel hole and coolant passage pattern is not possible in the region underlying the flange without degrading the operation of the seal. SUMMARY OF THE INVENTION Among the several objects of the present invention may be noted the provision of an improved high performance fuel element for a high temperature gas cooled reactor. The fuel element has increased core power density by including fuel holes and accompanying coolant passages in the region underlying the flange, but without compromising the sealing function and without mechanically weakening the flange. Stacked fuel elements are proportioned to define plenums therebetween so that a single blockage in one coolant passage in one element does not render inoperative vertically aligned passages in other elements because the presence of the plenums enables communication of coolant through all passages opening onto it to shunt around the blockage. Other aspects and features of the present invention will be, in part, apparent and, in part, pointed out in the following specification and in the accompanying claims and drawings. Briefly, the fuel element of the present invention includes an elongate block having substantially parallel, spaced, first and second end surfaces. The first end surface has a peripheral sealing flange while the second end surface has a peripheral sealing recess sized to receive the flange. The block has a plurality of first coolant passages disposed inwardly of the flange and recess and a plurality of elongate fuel holes disposed inwardly of the flange and recess. The block also includes a plurality of peripheral longitudinal second coolant passages extending intermediate the end surfaces and in general alignment with the flange and the recess. The block includes two bypasses for each peripheral coolant passage. One bypass intersects the peripheral passage adjacent the first end surface and intersects a first passage, and the other bypass intersects the second passage adjacent the second end surface and intersects a first passage so that coolant flowing through the second passages enters and exits the block through the first coolant passages.
	abstract	A multi-leaf collimator is disclosed which alleviates the problems of inter-leaf leakage and pixellation. The collimator comprises a first multi-leaf collimator set, a second multi-leaf collimator set at an acute angle to the first, and a third multi-leaf collimator set at an acute angle to the second. Each multi-leaf collimator set will usually include a pair of leaf banks mutually opposed to each other. The acute angle between the first and the second multi-leaf collimator set is preferably the same as the acute angle between the second and the third set. A suitable angle is about 60°. To improve the penumbra characteristics, (i) the leaves of the multi-leaf collimator closest to the radiation source can be deeper in the direction of the radiation than the leaves of a multi-leaf collimator more distant from the radiation source, (ii) the leaves of the multi-leaf collimator furthest from the radiation source can be shallower in the direction of the radiation than the leaves of a multi-leaf collimator closer to the radiation source, (iii) the tips of the leaves of the multi-leaf collimators can be rounded (iv) the radius of curvature of the tips of the leaves of the multi-leaf collimator closest to the radiation source can be greater than the radius of curvature of the tips of the leaves of a multi-leaf collimator more distant from the radiation source, and (v) the radius of curvature of the tips of the leaves of the multi-leaf collimator furthest from the radiation source can be less than the radius of curvature of the tips of the leaves of a multi-leaf collimator closer to the radiation source. In general, it is also preferred that the first multi-leaf collimator is closest to the radiation source, the third multi-leaf collimator is furthest from the radiation source, and the second multi-leaf collimator is between the first and third multi-leaf collimators.
047724455	summary	BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates in general to signal validation systems, and more specifically to a signal validation system in the control system of a nuclear reactor; the signal validation system being capable of determining direct current (DC) drift and noise components in signal discrepancies. 2. Description of the Related Art Reliability is an important consideration in many areas of technology, such as advanced avionic systems and the control systems of nuclear reactors. The use of redundant components, at least two, and more typically three or four components, is one technique that is used to increase reliability. The advantage of redundant components is that when a failure of one of the components is detected, the remaining component(s) which produce signals conveying the same information can still be used. Thus, system reliability becomes a function of the ability to identify and handle component failures. In the case of signals output by sensors, several types of failures are possible, including: bias--due to D.C. drift or noise, hardover--to a maximum or minimum level; sticking--at a given level; or common mode--where more than one sensor fails in the same manner, more or less simultaneously. In the case of sensors which output positive and negative values corresponding to the maximum and minimum values of a hardover error, null failure, resulting in the output of a zero value, is also possible. A powerful tool for identifying many types of failures while requiring relatively little variation for specific control systems, is provided by the parity-space algorithm. The parity-space algorithm was originally developed for advanced avionic systems as described in Potter and Suman, "Thresholdless Redundancy Management with Arrays of Skewed Instruments," Integrity in Electronic Flight Control Systems, NATO AGARDOGRAPH-224, 1977, pages 15-1 to 15-25 incorporated by reference herein. The application of the parity-space algorithm to control of nuclear reactors is described in a report available from the Electric Power Research Institute, Inc. as the Final Report dated Nov. 19, 1981 of NP-2110, Research Project 1541, by Deckert et al., entitled On-line Power Plant Signal Validation Technique Utilizing Parity-Space Representation and Analytic Redundancy incorporated by reference herein. As described therein, application of the parity-space algorithm to a specific system only requires determination of an error boundary for each sensor in the system. The parity-space algorithm provides information concerning discrepancies between redundant measurements of a parameter. Rather than comparing the measurements against a reference value, the parity-space algorithm looks at the differences between the values. As a result, the number of dimensions q of a parity vector generated by the parity-space algorithm is equal to the number of measurements of a parameter minus the dimensions of the parameter. For example, according to the parity-space algorithm, l measurements of a scalar parameter produce a parity vector having q=l-1 dimensions. One particular type of parity space has been termed "orthogonal parity space" by Potter and Suman in their article referenced above. As defined therein, orthogonal parity space has the following properties. An orthogonal parity vector p is defined according to equation (1), where V is an upper triangular matrix that transforms l measurements in an l by 1 column vector m into the parity vector p. EQU p=Vm (1) The measurement vector m is defined according to equation (2), where x is the actual value of the parameter being measured and has n dimensions where n equals 1 if the parameter being measured is a scaler, .epsilon. is the error in each of the measurements, and H is an l by n matrix. EQU m=Hx+.epsilon. (2) Thus, when a scalar is measured by three sensors, H is defined by equation (3). ##EQU1## In orthogonal parity space, matrix V is defined to have the properties of equation (5) where matrix K is defined as in equation (4). EQU K=(H.sup.T H).sup.-1 H.sup.T ( 4) EQU V.sup.T V=I-HK=W (5) From equation (5) it follows that equations (6) and (7) are true. EQU VV.sup.T =KH=I (6) EQU VH=KV.sup.T =0 (7) Given the above characteristics of matrix V, Potter and Suman have found that the elements of the matrix V are defined by equations (8)-(12). ##EQU2## The simplest application of the parity-space algorithm in orthogonal parity space occurs when a scalar parameter (n=1) is measured by three sensors (l=3). In this case, the matrix H is defined by equation (3) and, as defined in equation (4), K=1/3[1,1,1]. Using the definition in equation (5), the elements of matrix W have the values in equation (13). ##EQU3## The formulas in equation (8)-(12) give the following results for matrix V. ##EQU4## The columns of matrix V are vectors of length .sqroot.2/3 which lie along the measurement axes in parity space. Plotting these vectors results in a positively valued measurement axis every 120.degree., as illustrated in FIG. 1. As a result of the special properties of orthogonal parity space, several meaningful values can be found using a minimum amount of calculation when the parameter being measured is a scalar. A residual .eta..sub.j can be found for each of the measurements m.sub.j by subtracting the mean m from each measurement m.sub.j, i.e., .eta..sub.j =m.sub.j -m, where m is calculated according to equation (15). ##EQU5## The residuals can then be reordered from smallest to largest, as indicated in equation (16). EQU .eta..sub.1 .ltoreq..eta..sub.2 .ltoreq. . . . .ltoreq..eta..sub.l ( 16) After the reordering, there is a one-to-one correspondence between the measurements m.sub.j and the residuals .eta..sub.j, but the residual .eta..sub.2, for example, is not necessarily the residual for the measurement m.sub.2. After such reordering, a projection p.sub.j of the parity vector along the measurement axis of each sensor j can be can be calculated according to equation (17). EQU P.sub.j =.sqroot.l/(l-1).multidot..eta..sub.j ( 17) Given measurements from three sensors, for example, the parity vector 10 will be two-dimensional and thus easily depicted on a display screen 20, as illustrated in FIG. 1. In the case of such a two-dimensional parity vector 10, it is relatively easy to convert the projection p.sub.j into two-dimensional component parity vectors (the coordinates of the parity vector in the plane), or into sensor components of the parity vector in the direction of the measurement axes, using appropriate geometric and trigonometric relationships. An example of conversion will be given in the Description of the Preferred Embodiment. Failure of any one of the sensors can be detected by analyzing the parity vector. When the sensors are assumed to have a uniform error boundary b, at least one of the sensors is in error if the inequality (18) is satisfied, where .delta..sub.a is defined by equations (19a) and (19b). ##EQU6## In many cases, it is possible to identify which of the sensors has failed by calculating orthogonal components ##EQU7## in accordance with equation (20) for each of the sensors. ##EQU8## Since the residuals .eta..sub.j were ordered according to equation (16) above, the orthogonal component ##EQU9## will have the largest value of any of the orthogonal components. Therefore, if the orthogonal component ##EQU10## is small, i.e., the inequality in equation (21), where .delta..sub.l-1 is defined by equations (19a) and (19b), is true for j=1, then no inconsistency has been detected in the measurements supplied by the sensors and the value of the parameter measured by the sensors can be estimated as the mean m. ##EQU11## If the inequality in equation (21) is not satisfied for j=1, then the inequality is tested repeatedly for each value of j=2 through j=l. As j gets larger, the value of p.sup.2.sub.j will get smaller. If the inequality in equation (7) is satisfied for a value of j between 2 and l-1, inclusive, then the sensor which produced the inconsistency cannot be positively identified, and the best estimate for the value of the parameter measured by the sensors is m, where m is defined by equation (22). ##EQU12## If the first value of j which satisfies the inequality in equation (21) is l, then the sensor which generated the residual .eta..sub.l can be identified as having produced the inconsistent measurement and equation (22), with j=l, can be used for the best estimate m of the value of the parameter measured by the sensors. If none of the measurements can be identified as having been inconsistent, then the above procedure is repeated, throwing out the measurement which generated the largest residual .eta..sub.l. This is equivalent to decrementing the value of l by 1 and repeating equations (15) through (22). However, if the value of l is decremented below three, i.e., only two measurements are left, without isolating an inconsistent measurement, it is impossible to isolate the inconsistent measurement using the conventional parity-space algorithm. Assuming this does not occur, when the equation in (21) is satisfied and the value of the decremented l is at least three, then the estimate m for the value of the parameter measured by the sensors can be calculated according to equation (22). However, if the value of j which satisfies the inequality in equation (21) equals the value of the decremented l, it is necessary to compare the measurements of the excluded sensors with the measurement of the sensor having the orthogonal component ##EQU13## which satisfied equation (21) to determine whether the difference therebetween is less than the error-bound b. In other words, if the inequality in equation (23) is true for any value of k greater than the value of j and less than or equal to the original value of l, where the value of j equals the value of the decremented l, then a common mode inconsistency has occurred which the parity-space algorithm is unable to isolate. EQU .vertline.m.sub.k -m.sub.j .vertline..ltoreq.2b (23) When a sensor is identified as having generated consecutive inconsistent measurements, for example, three times, then that sensor is identified as having failed. As described above, although the basic parity-space algorithm is extremely powerful, it has limitations with respect to the types of failures which are detected. For example, a sensor may have a significant amount of DC drift, e.g., due to poor calibration, without having actually failed. Since the parameter-space algorithm does not distinguish between noise and DC drift contributions to inconsistent measurements, the information which could be provided by analysis of these components is not utilized. SUMMARY OF THE INVENTION An object of the present invention is to provide a system for determining direct current drift and noise levels in redundant sensors using parity-space signal validation. A further object of the present invention is to identify one or more failed sensors in situations in which parity-space signal validation is unable to identify a failed sensor. Another object of the present invention is to provide a direct current drift signal for each sensor in a system utilizing redundant sensors to permit remote calibration of the sensors. The above mentioned objects are attained by utilizing a method of measuring direct current drift and noise in samples of sensor signals received from corresponding sensors, including the step of converting the samples of the sensor signals into parity vector signals, each of the parity vector signals representing inconsistancy among a corresponding sample of the sensor signals. The method also includes the steps of converting the parity vector signals into a direct current drift signal by producing a first running average of the parity vector signals and producing an instantaneous noise signal for a corresponding parity vector signal by subtracting the direct current drift signal from the corresponding parity vector signal. These objects, together with other objects and advantages which will be subsequently apparent, reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part hereof, wherein like reference numerals refer to like parts throughout.
	description	This application is a continuation of U.S. patent application Ser. No. 15/437,338, filed on Feb. 20, 2017, which is a continuation of U.S. patent application Ser. No. 14/402,666, filed on Apr. 20, 2015, which is a U.S. National Stage of International Application No. PCT/JP2013/057471, filed on Mar. 15, 2013, which claims priority to Japanese Patent Application No. 2012-115533 filed on May 21, 2012, the contents of each of which are incorporated herein by reference. The present invention relates to a reflective mirror, a projection optical system, an exposure apparatus, and a device manufacturing method. Relating to exposure apparatuses for use in a photolithography process, EUV exposure apparatuses in which extreme ultraviolet (EUV) light is used as exposure light have been proposed, as disclosed, for example, in the following Patent Document 1. In an optical system of an EUV exposure apparatus, a multilayer-film reflective mirror having a multilayer film capable of reflecting at least a portion of incident light is used. [Patent Document 1] U.S. Patent Application Publication No. 2005/157384 In multilayer-film reflective mirrors, there is a possibility that the reflectance of the multilayer film will change according to the incident angle of the light with respect to the multilayer film. For example, when the reflectance of the multilayer film decreases, there is a possibility that exposure light of a desired intensity will not be irradiated onto a substrate. Consequently, there is a possibility that exposure defects will be generated and defective devices will be manufactured. An object of aspects of the present invention is to provide a reflective mirror with high reflectance. Another object of the aspects of the present invention is to provide a projection optical system and an exposure apparatus which can suppress the generation of exposure defects. Accordingly, the throughput of the exposure apparatus is improved. Still another object of the aspects of the present invention is to provide a device manufacturing method which can suppress the generation of defective devices. Accordingly, the throughput of the device manufacturing is improved. According to a first aspect of the present invention, there is provided a reflective mirror reflecting incident light, the reflective mirror including: a base, and a multilayer film configured to reflect at least a portion of the incident light and having a first layer and second layer that are laminated alternately on the base, the multilayer film being provided with a first portion having a first thickness and with a second portion having a second thickness different from the first thickness, the second portion being provided at a position rotationally symmetric to a position of the first portion about an optical axis of the reflective mirror. According to a second aspect of the present invention, there is provided a projection optical system including a plurality of optical elements, the projection optical system projecting an image of a first surface onto a second surface, and at least one of the optical elements being the reflective mirror according to the first aspect. According to a third aspect of the present invention, there is provided an exposure apparatus for exposing a substrate to exposure light, the exposure apparatus including the reflective mirror according to the first aspect. According to a fourth aspect of the present invention, there is provided a device manufacturing method including exposing a substrate using the exposure apparatus according to the third aspect, and developing the exposed substrate. According to the aspects of the present invention, it is possible to suppress a decrease in reflectance in the multilayer film. In addition, according to the aspects of the present invention, it is possible to suppress the generation of exposure defects and the generation of defective devices. Accordingly, it is possible to use a reflective mirror with high reflectance. In addition, the throughput of the exposure apparatus is improved. Below, description will be given of embodiments of the present invention with reference to the diagrams; however, the present invention is not limited to the description. In the following description, an XYZ rectangular coordinate system is established, and the positional relationship of respective members is described with reference to the XYZ rectangular coordinate system. A predetermined direction within a horizontal plane is made the X axis direction, a direction orthogonal to the X axis direction within the horizontal plane is made the Y axis direction, and a direction orthogonal to both the X axis direction and the Y axis direction (that is, a perpendicular direction) is made the Z axis direction. Rotation (tilt) directions about the X axis, the Y axis, and the Z axis are made the θX, θY and θZ directions, respectively. FIG. 1 is a schematic view showing an example of a multilayer-film reflective mirror 10 (reflective mirror) according to the present embodiment. In FIG. 1, the multilayer-film reflective mirror 10 is provided with a base 5, and a multilayer film 4 having a first layer 1 and second layer 2 laminated alternately on the base 5 and capable of reflecting at least a portion of incident light EL. In the present embodiment, the light EL incident on the multilayer film 4 contains extreme ultraviolet light. Extreme ultraviolet light is, for example, an electromagnetic wave in a soft X-ray region with a wavelength of approximately 11 to 14 nm. Extreme ultraviolet light is reflected by the multilayer film 4. In the following description, extreme ultraviolet light will be referred to as EUV light as appropriate. Here, the light EL incident on the multilayer film 4 may be an electromagnetic wave in a soft X-ray region of approximately 5 to 50 nm or may be an electromagnetic wave of approximately 5 to 20 nm. In addition, the light EL may be an electromagnetic wave with a wavelength of 193 nm or less. For example, the light EL may be vacuum ultraviolet (VUV) light such as ArF excimer laser light (wavelength of 193 nm) or F2 laser light (wavelength of 157 nm). The base 5 is, for example, formed of ultra-low expansion glass. As the base 5, ULE manufactured by Corning Inc., Zerodur (registered trademark) manufactured by Schott AG, or the like is used. The multilayer film 4 includes the first layer 1 and second layer 2 laminated alternately with a predetermined periodic length d. The periodic length d refers to the sum (d1+d2) of the thickness d1 of the first layer 1 and the thickness d2 of the second layer 2. Based on the theory of optical interference, each of the thickness d1 of the first layer 1 and the thickness d2 of the second layer 2 is set such that the reflected waves reflected by each interface with the first layer 1 and the second layer 2 coincide with one another in phase. In the following description, one set of the first layer 1 and the second layer 2 is referred to as a layer pair 7 as appropriate. In the present embodiment, with regard to one layer pair 7, the first layer 1 is arranged on the base 5 side (on the −Z side in the diagram) with respect to the second layer 2. The multilayer film 4 is formed by the layer pair 7 of the first layer 1 and the second layer 2 being laminated on the base 5. For example, there are tens to hundreds of the layer pairs 7 laminated on the base 5. As an example, in the present embodiment, there are 50 layer pairs 7 laminated on the base 5. In the present embodiment, the thickness of the multilayer film 4 includes a thickness Da of the entirety of the multilayer film 4 which is the sum of the thicknesses of the plurality (for example, 50) of the layer pairs 7. In addition, in the present embodiment, the thickness of the multilayer film 4 includes the thickness of one layer pair 7 including one first layer 1 and one second layer 2. That is, in the present embodiment, the thickness of the multilayer film 4 includes the periodic length d (=d1+d2). The first layer 1 is formed of a material with a refractive index differing greatly from the refractive index of vacuum with respect to EUV light. The second layer 2 is formed of a material with a refractive index differing little from the refractive index of vacuum with respect to EUV light. In the present embodiment, the first layer (heavy atom layer) 1 is formed of molybdenum (Mo). The second layer (light atom layer) 2 is formed of silicon (Si). That is, the multilayer film 4 of the present embodiment is a Mo/Si multilayer film where a molybdenum layer (Mo layer) and a silicon layer (Si layer) are laminated alternately. The refractive index of vacuum n is 1. In addition, for example, the refractive index of molybdenum nMo with respect to EUV light with a wavelength of 13.5 nm is 0.92, and the refractive index of silicon nSi is 0.998. In this manner, the second layer 2 is formed of a material where the refractive index with respect to EUV light is substantially equal to the refractive index of vacuum. As shown in FIG. 1, in the present embodiment, there is a distribution in the thickness of the multilayer film 4. In other words, the multilayer film 4 has a plurality of portions with different thicknesses. As shown in FIG. 1, the multilayer film 4 has at least a first portion PA1 with a first thickness and a second portion PA2 with a second thickness which is different from the first thickness. In the present embodiment, the distribution of the thickness of the multilayer film 4 (the thickness distribution of the multilayer film) does not have an axis of rotational symmetry. The multilayer film 4 has a thickness distribution which is not rotationally symmetric (a non-rotationally symmetric thickness distribution). In the present embodiment, the distribution of the thickness of the multilayer film 4 is non-rotationally symmetric with respect to the center of the region to which the light EL is incident on a surface 4S of the multilayer film 4. In the present embodiment, the distribution of the thickness of the multilayer film 4 is non-rotationally symmetric with respect to any position on the XY plane on the surface 4S of the multilayer film 4. In addition, in the present embodiment, the shape of a surface 5S of the base 5 where the multilayer film 4 is formed is determined such that an aberration caused by the distribution of the thickness of the multilayer film 4 are reduced. In the example shown in FIG. 1, the shape of the surface 5S of the base 5 is determined such that a surface 5S2 of the base 5 where the second portion PA2 is formed is arranged at a position further from the surface 4S of the multilayer film 4 than that of a surface 5S1 of the base 5 where the first portion PA1 is formed. FIG. 2 is a diagram schematically showing the surface 4S of the multilayer film 4. In FIG. 2, the thickness of the multilayer film 4 is different in the first position (the first portion PA1) and the second position (the second portion PA2) of the surface 4S. In the example shown in FIG. 2, the first portion PA1 and the second portion PA2 are at an equal distance from an optical axis AX of the multilayer-film reflective mirror 10. That is, the distance between the first portion PA1 and the optical axis AX is equal to the distance between the second portion PA2 and the optical axis AX. In other words, the first portion PA1 and the second portion PA2 are positioned on a circle centered on the optical axis AX. This shows that the second portion PA2 is provided at a position which is rotationally symmetric about the optical axis (reference axis) AX of the multilayer-film reflective mirror 10 with respect to the first portion PAL In this manner, in the present embodiment, the distribution of the thickness of the multilayer film 4 does not have an axis of rotational symmetry (a point of rotational symmetry). In other words, the distribution of the thickness of the multilayer film 4 is not a rotationally symmetric distribution. This shows that, in the first portion PA1 and the second portion PA2 which are rotationally symmetric about the optical axis (reference axis) AX, the thicknesses of the multilayer film 4 are different from each other. That is, the multilayer-film reflective mirror 10 has a thickness distribution where the thickness of the multilayer film 4 changes in the azimuthal direction of the optical axis AX (for example, the rotation direction around the optical axis AX, the θZ direction, or the like). For example, the multilayer-film reflective mirror 10 has a thickness distribution which continuously changes along the azimuthal direction of the optical axis AX. In addition, in the present embodiment, the distribution of the thickness of the multilayer film 4 is line symmetric with respect to a line which passes through the center of the region to which the light EL is incident on the surface 4S of the multilayer film 4. In addition, in the present embodiment, the distribution of the thickness of the multilayer film 4 is line symmetric with respect to a line which passes through the optical axis AX and the center of the region to which the light EL is incident on the surface 4S of the multilayer film 4. In addition, in the present embodiment, the distribution of the thickness of the multilayer film 4 has a finite number of axes of rotational symmetry in the surface 4S of the multilayer film 4. The multilayer film 4 has a thickness distribution which has a finite number of axes of rotational symmetry in the surface 4S of the multilayer film 4. Note that, in either case, the multilayer-film reflective mirror 10 is provided with the first portion PA1 which has the first thickness and the second portion PA2 which has a second thickness different from the first thickness, second portion PA2 being provided at a position rotationally symmetric about the optical axis AX of the multilayer-film reflective mirror 10 with respect to a position of the first portion PA1. For example, even in a case where the distribution of the thickness of the multilayer film 4 has a finite number of axes of rotational symmetry in the surface 4S of the multilayer film 4, at least a part of the multilayer-film reflective mirror 10 has portions where the thicknesses of the multilayer film are different from each other at positions rotationally symmetric about the optical axis AX. FIG. 3 is a diagram showing a relationship between the incident angle of the light EL with respect to the surface 4S of the multilayer film 4 and the reflectance of the multilayer film 4 with respect to the incident light EL. When the thickness of the multilayer film 4 changes, the reflectance characteristic with respect to the incident angle changes. For example, as shown by lines Ca1 and Cb1 in FIG. 3, the multilayer film 4 with the periodic length da is capable of reflecting the light EL incident at an incident angle of from θah to θar. The multilayer film 4 with a periodic length db is capable of reflecting the light EL incident at an incident angle of from θbh to θbr. In addition, the multilayer film 4 with the periodic length da reflects the light EL, which is incident at the incident angle θam, with a reflectance H1. The multilayer film 4 with the periodic length db reflects the light EL, which is incident at the incident angle θbm, with the reflectance H1. The incident angle θam is a value in the middle of the incident angles of from θah to θar. The incident angle θbm is a value in the middle of the incident angles of from θbh to θbr. The reflectance H1 is the maximum reflectance (peak reflectance) when the light EL is incident at an incident angle of from θah to θar on the surface 4S of the multilayer film 4 with the periodic length da. The reflectance H1 is the maximum reflectance (peak reflectance) when the light EL is incident at an incident angle of from θbh to θbr on the surface 4S of the multilayer film 4 with the periodic length db. Note that, in FIG. 3, the lines Ca1 and Cb1 have bilateral symmetry; however, there is a possibility that the lines will not have bilateral symmetry. In addition, FIG. 3 shows an example where the value in the middle of the incident angles is the maximum reflectance; however, there is a possibility that the value in the middle of the incident angles will not be the maximum reflectance. In this manner, the incident angle where the reflectance H1 is obtained is θam when the light EL is incident on the surface 4S of the multilayer film 4 with the periodic length da, and the incident angle where the reflectance H1 is obtained is θbm when the light EL is incident on the surface 4S of the multilayer film 4 with the periodic length db. In other words, it is possible to obtain the reflectance H1 by setting the periodic length of the multilayer film 4 where the light EL is incident at the incident angle θam to da, and it is possible to obtain the reflectance H1 by setting the periodic length of the multilayer film 4 where the light EL is incident at the incident angle θbm to db. In addition, as shown in FIG. 3, the reflectance is substantially zero even when the light EL is incident on the surface 4S of the multilayer film 4 with the periodic length da at the incident angle θbm. In other words, the light EL is substantially not reflected even when the light EL is incident on the surface 4S of the multilayer film 4 with the periodic length da at the incident angle θbm. In addition, the reflectance is substantially zero even when the light EL is incident on the surface 4S of the multilayer film 4 with the periodic length db at the incident angle θam. In other words, the light EL is substantially not reflected even when the light EL is incident on the surface 4S of the multilayer film 4 with the periodic length db at the incident angle θam. In addition, as shown by line Ca2 in FIG. 3, it is possible to adjust the incident angle (incident angle range) of the light EL which the multilayer film 4 is capable of reflecting by adjusting at least one of the thickness d1 of the first layer 1 and the thickness d2 of the second layer 2. For example, it is possible to increase the incident angle range of the light EL which the multilayer film 4 is capable of reflecting by adjusting at least one of the thickness d1 of the first layer 1 and the thickness d2 of the second layer 2. In addition, it is possible to decrease the incident angle range of the light EL which the multilayer film 4 is capable of reflecting by adjusting at least one of the thickness d1 of the first layer 1 and the thickness d2 of the second layer 2. In the example shown by line Ca2, it is possible for the multilayer film 4 to reflect the light EL which is incident at the incident angles of from θaf to θat. In addition, the maximum reflectance is adjusted by adjusting at least one of the thickness d1 of the first layer 1 and the thickness d2 of the second layer 2. In the example shown in FIG. 3, the reflectance (maximum reflectance) H2 is smaller than the reflectance (maximum reflectance) H1. In addition, it is even possible to adjust the incident angle (incident angle range) which the multilayer film 4 is capable of reflecting by adjusting the thickness Da of the entire multilayer film 4. In addition, it is even possible to adjust the maximum reflectance of the multilayer film 4 by adjusting the thickness Da of the entire multilayer film 4. In this manner, at least one of the incident angle (incident angle range) of the light EL which can be reflected, and the reflectance (maximum reflectance) with respect to the incident angle of the light EL is determined based on the thickness of the multilayer film 4, which includes at least one of the periodic length d of the multilayer film 4, the thickness d1 of the first layer 1, the thickness d2 of the second layer 2, and the thickness Da of the entire multilayer film 4. In addition, it is possible to adjust at least one of the incident angle range and the maximum reflectance by adjusting the thickness of the multilayer film 4. FIG. 4 is a schematic view showing a multilayer film 4J according to a Comparative Example. In FIG. 4, the light EL is incident at a first incident angle θa to a position (portion PAJ1) on a surface 4SJ of the multilayer film 4J, and the light EL is incident at a second incident angle θb to a position (portion PAJ2) which is different from the portion PAJ1. In the multilayer film 4J, the thickness of the portion PAJ1 and the thickness of the portion PAJ2 are equal to each other. The light EL incident on the portion PAJ1 is reflected. On the other hand, the light EL incident on the portion PAJ2 is not reflected. FIG. 5 is a schematic view showing the multilayer film 4 according to the present embodiment. The light EL is incident at the first incident angle θa to a first position (first portion PA1) on the surface 4S of the multilayer film 4, and the light EL is incident at the second incident angle θb to a second position (second portion PA2) which is different from the first portion PA1. In the multilayer film 4, the thickness of the first portion PA1 and the thickness of the second portion PA2 of the multilayer film 4 are different from each other. The first portion PA1 has a thickness capable of reflecting the light EL which is incident at the first incident angle θa. The second portion PA2 has a thickness capable of reflecting the light EL which is incident at the second incident angle θb. In the present embodiment, the thicknesses of the multilayer film 4 in the first portion PA1 and the second portion PA2 are determined such that the reflectances of the light EL in the first portion PA1 (first position) and the second portion PA2 (second position) are high, and the difference between the reflectances is reduced. FIG. 6 is a diagram showing an example of a projection optical system PL according to the present embodiment. The projection optical system PL has a plurality of optical elements and projects an image of a first surface BJ onto a second surface IM. The light EL from the first surface BJ is irradiated onto the second surface IM via the plurality of optical elements of the projection optical system PL. In the present embodiment, at least one of the plurality of optical elements of the projection optical system PL is the multilayer-film reflective mirror 10 having the multilayer film 4. For example, an optical element having the largest incident angle range of the light EL out of the plurality of optical elements of the projection optical system PL may be the multilayer-film reflective mirror 10 according to the present embodiment. In the example shown in FIG. 6, after being reflected by an optical element M1, the light EL from the first surface BJ is irradiated onto the second surface IM via an optical element M2, an optical element M3, an optical element M4, an optical element M5, and an optical element M6. In such a case, for example, the optical element M3 may be the multilayer-film reflective mirror 10, or the optical element M5 may be the multilayer-film reflective mirror 10. Naturally, at least one of the optical elements M1, M2, M4, M6 may be the multilayer-film reflective mirror 10, or all of the optical elements M1 to M6 may be the multilayer-film reflective mirror 10. FIG. 7 and FIG. 8 are diagrams showing examples of distributions of the incident angle of the light EL with respect to the multilayer film 4. As shown in FIG. 7 and FIG. 8, in the present embodiment, the distribution of the incident angle of the light EL with respect to the multilayer film 4 is line symmetric with respect to a line parallel with the Y axis in the diagram. The direction parallel with the Y axis is a scanning direction (scan direction) when a substrate P is exposed in an exposure apparatus EX to be described below. For example, in FIG. 7, the multilayer film 4 has a portion where the incident angle of the light EL is 23.10°. In addition, the multilayer film 4 has a portion where the incident angle of the light EL is 1.155°. FIG. 9 is an example showing a difference in the incident angle distribution of the maximum incident angle of the light EL incident on the multilayer film 4 (for example, FIG. 7) and the incident angle distribution of the minimum incident angle (for example, FIG. 8). The incident angle of the light EL incident on the multilayer film 4 changes in a case where the numerical aperture NA of the projection optical system PL changes, a case where the image height changes, or the like. In the present embodiment, for example, the multilayer film 4 is formed in consideration of the incident angle distribution of the maximum incident angle and the incident angle distribution of the minimum incident angle. In one example, it is possible for the multilayer film 4 to have the thickness distribution shown in FIG. 9. In such a case, in the multilayer-film reflective mirror 10, the thickness of the multilayer film 4 changes according to the gradations shown FIG. 9. For example, the multilayer film 4 has a high film thickness at points in FIG. 9 showing high values, and has a low film thickness at points showing low values. In addition, in the present embodiment, the distribution of the thickness of the multilayer film 4 is line symmetric with respect to a line parallel with the Y axis. The direction parallel with the Y axis is a scanning direction (scan direction) when the substrate P is exposed in the exposure apparatus EX to be described below. The distribution of the thickness of the multilayer film 4 may be represented by the rectangular coordinate system. In addition, the distribution of the thickness of the multilayer film 4 may be represented by the polar coordinate system. For example, the distribution of the thickness of the multilayer film 4 may be represented by a polynomial series representing the distribution of the thickness of the multilayer film 4 using the distance from the optical axis AX on the surface 4S of the multilayer film 4 and polar coordinates. In addition, the distribution of the thickness of the multilayer film 4 may be represented by Zernike polynomials. FIG. 10 is a diagram showing an example of the exposure apparatus EX according to the present embodiment. The exposure apparatus EX of the present embodiment is an EUV exposure apparatus which exposes the substrate P to EUV light. The multilayer-film reflective mirror 10 described above is used as an optical system of the EUV exposure apparatus EX according to the present embodiment. In FIG. 10, the exposure apparatus EX is provided with a mask stage 11 capable of moving while holding a mask M, a substrate stage 12 capable of moving while holding the substrate P onto which exposure light EL is irradiated, a light source apparatus 13 which generates the light (exposure light) EL which includes EUV light, an illumination optical system IL which illuminates the mask M held by the mask stage 11 with the exposure light EL emitted from the light source apparatus 13, the projection optical system PL which projects an image of a pattern of the mask M illuminated by the exposure light EL onto the substrate P, and a chamber apparatus VC which has a vacuum system which forms a predetermined space through which at least the exposure light EL passes and sets the predetermined space to a vacuum state (for example, 1.3×10−3 Pa or less). The substrate P includes a substrate where a photosensitive film is formed on a base such as a semiconductor wafer. The mask M includes a reticle where a device pattern which is projected onto the substrate P is formed. In the present embodiment, EUV light is used as the exposure light EL, and the mask M is a reflective mask which has a multilayer film capable of reflecting EUV light. The multilayer film of the reflective mask includes, for example, a Mo/Si multilayer film, and a Mo/Be multilayer film. The exposure apparatus EX illuminates the reflecting surface (pattern forming surface) of the mask M where the multilayer film is formed with the exposure light EL and exposes the substrate P to reflected light of the exposure light EL reflected by the mask M. The light source apparatus 13 of the present embodiment is a laser-excited plasma light source apparatus which includes a laser apparatus 15 for emitting laser light, and a supply member 16 for supplying a target material such as a xenon gas. The laser apparatus 15 generates laser light with a wavelength in the infrared region and the visible region. The laser apparatus 15 includes, for example, a YAG laser, an excimer laser, or the like using semiconductor laser excitation. In addition, the light source apparatus 13 is provided with a first collection optical system 17 for collecting laser light emitted from the laser apparatus 15. The first collection optical system 17 collects the laser light emitted from the laser apparatus 15 at a position 19. The supply member 16 has a supply port which supplies the target material to the position 19. The laser light collected by the first collection optical system 17 is irradiated onto the target material supplied from the supply member 16. The target material irradiated by the laser light is heated to a high temperature due to the energy of the laser light. Then, the target material is excited into a plasma state and generates light including EUV light during a transition to a low potential state. Note that, the light source apparatus 13 may be a plasma discharge light source apparatus. The light source apparatus 13 generates light (EUV light) which has a spectrum in the extreme ultraviolet region. The exposure apparatus EX is provided with a second light-collection mirror 18 arranged at the periphery of the position 19. The second light-collection mirror 18 includes an elliptical mirror. The second light-collection mirror 18 which includes the elliptical mirror is arranged such that a first focal point and the position 19 are substantially matched. The EUV light (exposure light) EL collected at a second focal point by the second light-collection mirror 18 is supplied to the illumination optical system IL. The illumination optical system IL includes a plurality of optical elements 20, 21, 22, 23, 24 to which the exposure light EL emitted from the light source apparatus 13 is supplied and illuminates the mask M with the exposure light EL emitted from the light source apparatus 13. At least one of the optical elements 20, 21, 22, 23, 24 of the illumination optical system IL may be the multilayer-film reflective mirror 10 described above. The optical element 20 of the illumination optical system IL is a third light-collection mirror functioning as a collimator mirror, to which the exposure light EL from the second light-collection mirror 18 is supplied. The exposure light EL from the second light-collection mirror 18 is guided to the third light-collection mirror 20. The third light-collection mirror 20 includes a parabolic mirror. The third light-collection mirror 20 is arranged such that the focal point thereof and the second focal point of the second light-collection mirror 18 are substantially matched. In addition, the illumination optical system IL has an optical integrator 25. In the present embodiment, the optical integrator 25 includes a reflective fly eye mirror optical system. The reflective fly eye mirror optical system 25 includes an incident side fly eye mirror 21 and an emission side fly-eye mirror 22. The third light-collection mirror 20 supplies the exposure light EL to the incident side fly eye mirror 21 of the reflective fly eye mirror optical system 25, with the exposure light EL substantially collimated. The incident side fly eye mirror 21 includes a plurality of unit mirrors (reflecting element group) having reflecting surfaces disposed in parallel with each other, the reflecting surfaces having an arcuate shape substantially similar to an illumination field as disclosed, in for example, U.S. Pat. No. 6,452,661, and the like. The incident side fly eye mirror 21 is arranged at a position optically conjugate with the reflecting surface of the mask M and the surface of the substrate P, or in the vicinity thereof. In addition, the emission side fly eye mirror 22 includes a plurality of unit mirrors (reflecting element group) corresponding to the plurality of unit mirrors of the incident side fly eye mirror 21. Each of the unit mirrors of the emission side fly eye mirror 22 has a rectangular shape and is arranged in parallel. The emission side fly eye mirror 22 is arranged at a position optically conjugate with the pupil position of the projection optical system PL, or in the vicinity thereof. The collimated light from the third light-collection mirror 20 is incident on the incident side fly eye mirror 21 and undergoes wave front splitting through the incident side fly eye mirror 21. Each of the unit mirrors of the incident side fly eye mirror 21 collects the incident light and forms a plurality of light collection points (light source image). A plurality of unit mirrors of the emission side fly eye mirror 22 are arranged at positions near where the plurality of light collection points are formed. A plurality of light collection points (secondary light source) which correspond to the number of unit mirrors of the emission side fly eye mirror 22 are formed on the emission surface of the emission side fly eye mirror 22 or in the vicinity thereof. In addition, the illumination optical system IL has a condenser mirror 23. The condenser mirror 23 is arranged such that a focal position of the condenser mirror 23 and the position in the vicinity of the secondary light source which is formed by the reflective fly eye mirror optical system 25 are substantially matched. The light from the secondary light source formed by the reflective fly eye mirror optical system 25 is reflected and collected by the condenser mirror 23 and supplied to the mask M via an optical path bending mirror 24. In this manner, the illumination optical system IL including the plurality of optical elements 20 to 24 uniformly illuminates an illumination region on the mask M with the exposure light EL emitted from the light source apparatus 13. The exposure light EL illuminated by the illumination optical system IL and reflected by the mask M is incident on the projection optical system PL. Note that, in order to spatially separate the optical path of the light supplied to the mask M and the optical path of the light reflected by the mask M to be incident on the projection optical system PL, the illumination optical system IL of the present embodiment is a non-telecentric system. In addition, the projection optical system PL is also a mask side non-telecentric system. The mask stage 11 is a stage capable of moving with six degrees of freedom in six directions, which are the X axis, Y axis, Z axis, θX, θY, and θZ directions, while holding the mask M. In the present embodiment, the mask stage 11 holds the mask M such that the reflecting surface of the mask M and the XY plane are substantially parallel. The position information of the mask stage 11 (mask M) is measured by a laser interferometer 41. The laser interferometer 41 measures position information relating to the X axis, Y axis, and θZ directions of the mask stage 11 using a measuring mirror provided in the mask stage 11. In addition, the surface position information of the surface of the mask M held by the mask stage 11 (position information relating to the Z axis, the θX, and the θY) is detected by a focus leveling detection system (not shown). The position of the mask M held by the mask stage 11 is controlled based on the measurement result made by the laser interferometer 41 and the detection result made by the focus leveling detection system. In addition, the exposure apparatus EX of the present embodiment is provided with a blind member 60 arranged at a position opposite to at least a portion of the reflecting surface of the mask M and limits the illumination region of the exposure light EL on the reflecting surface of the mask M as disclosed in, for example, Japanese Unexamined Patent Application Publication No. 2004-356415A, and the like. The blind member 60 has an opening through which the exposure light EL can pass and defines the illumination region of the exposure light EL on the reflecting surface of the mask M. The projection optical system PL includes a plurality of optical elements 31, 32, 33, 34, 35, 36 to which the exposure light EL from the mask M is supplied and projects an image of the pattern of the mask M illuminated by the exposure light EL onto the substrate P. At least one of the optical elements 31, 32, 33, 34, 35, 36 of the projection optical system PL may be the multilayer-film reflective mirror 10 described above. The projection optical system PL is provided with a first mirror pair including a first reflecting mirror 31 having a reflecting surface with a concave surface and a second reflecting mirror 32 having a reflecting surface with a concave surface, a second mirror pair including a third reflecting mirror 33 having a reflecting surface with a predetermined shape and a fourth reflecting mirror 34 having a reflecting surface with a concave surface, and a third mirror pair including a fifth reflecting mirror 35 having a reflecting surface with a convex surface and a sixth reflecting mirror 36 having a reflecting surface with a concave surface. In each of the mirror pairs, the first reflecting mirror 31, the third reflecting mirror 33, and the fifth reflecting mirror 35 are each arranged such that the reflecting surfaces face the object plane side (mask M side) of the projection optical system PL, and the second reflecting mirror 32, the fourth reflecting mirror 34, and the sixth reflecting mirror 36 are each arranged such that the reflecting surfaces face the image plane side (substrate P side) of the projection optical system PL. The exposure light EL from the mask M forms an intermediate image after being reflected by the first mirror pair in order of the first reflecting mirror 31 and the second reflecting mirror 32. The light from the intermediate image is reflected by the second mirror pair in order of the third reflecting mirror 33 and the fourth reflecting mirror 34. The light reflected by the second mirror pair is reflected by the third mirror pair in order of the fifth reflecting mirror 35 and the sixth reflecting mirror 36 to be guided to the substrate P. A field stop FS which limits the projection region on the substrate P is arranged at a position where the intermediate image is formed. An aperture stop AS which limits the numerical aperture NA of the projection optical system PL is arranged between the first reflecting mirror 31 and the second reflecting mirror 32 of the first mirror pair. The aperture stop AS has an opening with a variable size (diameter). The size (diameter) of the opening is controlled by an aperture stop control unit 51. The substrate stage 12 is a stage capable of moving with six degrees of freedom in six directions, which are the X axis, Y axis, Z axis, θX, θY, and θZ directions, while holding the substrate P. In the present embodiment, the substrate stage 12 holds the substrate P such that the surface of the substrate P and the XY plane are substantially parallel. Position information of the substrate stage 12 (substrate P) is measured by a laser interferometer 42. The laser interferometer 42 measures position information relating to the X axis, Y axis, and θZ directions of the substrate stage 12 using a measuring mirror provided in the substrate stage 12. In addition, the surface position information of the surface of the substrate P held by the substrate stage 12 (position information relating to the Z axis, the θX, and the θY) is detected by the focus leveling detection system (not shown). The position of the substrate P held by the substrate stage 12 is controlled based on the measurement result made by the laser interferometer 42 and the detection result made by the focus leveling detection system. When exposing the substrate P, the substrate stage 12 holding the substrate P is moved in the Y axis direction in synchronization with the movement of the mask stage 11 holding the mask M in the Y axis direction while the illumination optical system IL illuminates a predetermined illumination region on the mask M with the exposure light EL. As a result, the image of the pattern of the mask M is projected onto the substrate P via the projection optical system PL. As described above, according to the present embodiment, since the thickness of each position (each portion) of the multilayer film 4 is made to be different such that the light EL is reflected based on the incident angle of the light EL with respect to the surface 4S of the multilayer film 4 without the distribution of the thickness of the multilayer film 4 having an axis of rotational symmetry, it is possible for the multilayer film 4 to reflect the incident light EL with high reflectance. Accordingly, it is possible to suppress the generation of exposure defects caused by a decrease in the reflectance in the multilayer film and the generation of defective devices. For example, in a case where portions of a plurality of multilayer films 4 in a circle with the optical axis of the multilayer-film reflective mirror as the center are set to the same thickness, as described with reference to FIG. 3 and FIG. 4, there is a possibility that there will be a portion which is not capable of reflecting the light EL depending on the incident angle of the light EL. In addition, when trying to increase the incident angle range of the light EL in which the light EL can be reflected, for example, there is a possibility that the maximum reflectance will decrease as described with reference to the line Ca2 in FIG. 3. In the present embodiment, for example, the necessary thickness of the multilayer film 4 in each of the first portion PA1 and the second portion PA2 is calculated so as to obtain a target reflectance in each of the first portion PA1 and the second portion PA2. The calculated result is fitted to a function, and then the multilayer film 4 is manufactured. As a result, it is possible to manufacture the multilayer-film reflective mirror 10 having the multilayer film 4 with the desired reflectance. That is, it is possible to manufacture a reflective mirror with high reflectance. In addition, by using the multilayer-film reflective mirror 10 according to the present embodiment in at least one of the illumination optical system IL and the projection optical system PL, it is possible to suppress a decrease in the optical performance of these optical systems IL and PL and in the exposure performance of the exposure apparatus EX. Accordingly, throughput of the exposure apparatus is improved. Note that description was given of an example of a case where the multilayer film 4 is an Mo/Si multilayer film in each of the embodiments described above; however, for example, it is possible to change the material forming the multilayer film 4 according to the wavelength band of the EUV light. For example, in a case of using EUV light of a wavelength band close to 11.3 nm, it is possible to obtain a high reflectance by using an Mo/Be multilayer film where a molybdenum layer (Mo layer) and a beryllium layer (Be layer) are laminated alternately. In addition, in each of the embodiments described above, ruthenium (Ru), molybdenum carbide (Mo2C), molybdenum oxide (MoO2), molybdenum silicide (MoSi2), and the like may be used as the material for forming the first layer 1 of the multilayer film 4. In addition, it is possible to use silicon carbide (SiC) as the material forming the second layer 2 of the multilayer film 4. Alternatively, it is possible for the multilayer-film reflective mirror 10 to use a reflective mirror having a reflecting surface which is an aspherical surface or a free-form surface. In such a case, for example, it is possible to regard a straight line passing through the origin obtained from a formula representing the aspherical surface or free-form surface, or a straight line passing through the center or the center of gravity of the reflecting surface (a reference line or a reference axis) as the “optical axis”. In one embodiment, it is possible to determine the optical axis in the reflective mirror having a spherical reflecting surface or another reflecting surface as a design reference. Alternatively and/or additionally, it is possible to regard a straight line passing through the origin obtained from a formula representing a curved surface of the reflecting surface (a reference line or a reference axis), or a straight line passing through the center or the center of gravity of the reflecting surface (a reference line or a reference axis) as the optical axis, and it is possible to determine the optical axis as a design reference. In addition to a semiconductor wafer for manufacturing a semiconductor device, a glass substrate for a display device, a ceramic wafer for a thin-film magnetic head, an original plate (synthetic quartz or silicon wafer) of a mask or a reticle used in the exposure apparatus, or the like may be applied as the substrate P in the embodiment described above. As for the exposure apparatus EX, in addition to a scan type exposure apparatus of step-and-scan type (scanning stepper) in which while synchronously moving the mask M and the substrate P, the pattern of the mask M is scan-exposed, a step-and-repeat type projection exposure apparatus (stepper) in which the pattern of the mask M is exposed in a batch in the condition that the mask M and the substrate P are stationary, and the substrate P is successively moved stepwise can be used. Furthermore, in the step-and-repeat type exposure, after a reduced image of a first pattern is transferred onto the substrate P by using the projection optical system, in the state with the first pattern and the substrate P being substantially stationary, a reduced image of a second pattern may be exposed in a batch onto the substrate P, the reduced image of the second pattern being partially overlapped on the first pattern, by using the projection optical system, in a state with the second pattern and the substrate P being substantially stationary (a stitch type batch exposure apparatus). In addition, it is also possible to apply the stitch type exposure apparatus to a step-and-stitch type exposure apparatus transferring at least two patterns onto the substrate P in a partially overlapping manner, and moving the substrate P in sequence. In addition, for example, it is also possible to apply the present invention to an exposure apparatus which combines patterns of two masks on a substrate via a projection optical system, and double exposes a single shot region on the substrate at substantially the same time, using a single scan exposure light, as disclosed in U.S. Pat. No. 6,611,316, or the like. In addition, it is also possible to apply the present invention to a twin stage type exposure apparatus provided with a plurality of substrate stages as disclosed in U.S. Pat. No. 6,341,007, U.S. Pat. No. 6,400,441, U.S. Pat. No. 6,549,269, U.S. Pat. No. 6,590,634, U.S. Pat. No. 6,208,407, U.S. Pat. No. 6,262,796, and the like. Furthermore, for example, it is also possible to apply the present invention to an exposure apparatus provided with a substrate stage holding a substrate and a measurement stage on which is mounted a reference member where a reference mark is formed and/or various photoelectric sensors, as disclosed in U.S. Pat. No. 6,897,963 and the like. In addition, it is possible to apply the present invention to an exposure apparatus provided with a plurality of substrate stages and measurement stages. The types of the exposure apparatuses EX are not limited to exposure apparatuses for manufacturing semiconductor elements which expose semiconductor element patterns onto a substrate P, and are widely applicable to apparatuses including exposure apparatuses for manufacturing liquid crystal display elements or for manufacturing displays, and exposure apparatuses for manufacturing thin-film magnetic heads, picture elements (CCD), micromachines, MEMS, DNA chips, reticles, masks, and the like. The exposure apparatus EX of the present embodiment is manufactured by assembling various subsystems including each of the constituent elements listed in the Claims so as to maintain a predetermined mechanical precision, electrical precision, and optical precision. In order to ensure these precisions, adjustments to achieve the optical precision for the various optical systems, adjustments to achieve the mechanical precision for the various mechanical systems, and adjustments to achieve the electrical precision for the various electrical systems are performed before and after this assembly. The process of assembling the various subsystems into the exposure apparatus includes mechanical connections, wiring connections of electrical circuits, piping connections of air pressure circuits, and the like between the various subsystems. Before the process of assembling the various subsystems into the exposure apparatus, it is needless to mention that there are individual assembly processes for each of the subsystems. When the assembly processes of the various subsystems into the exposure apparatus are finished, comprehensive adjustment is performed and the various precisions are ensured for the exposure apparatus as a whole. Note that, it is desirable that the manufacturing of the exposure apparatus be performed in a clean room where the temperature, the cleanliness, and the like are controlled. As shown in FIG. 11, devices such as semiconductor devices are manufactured through: a step 201 of performing function and performance design for the device, a step 202 of creating the mask (reticle) based on this design step, a step 203 of manufacturing the substrate which is a base of the device, a substrate processing step 204 including substrate processing (exposure processing) for exposing the substrate P to exposure light from the pattern of the mask according to the embodiment described above and for developing the exposed substrate, a device assembly step (including treatment process such as a dicing process, a bonding process, and a packaging process) 205, an inspection step 206, and the like. By implementing the aspects of the present invention, the throughput of the device manufacturing is improved. Note that, it is possible to combine the conditions of each of the embodiments described above as appropriate. In addition, there may be cases where some constituent elements are not used. In addition, the disclosures of all of the published patents and US patents relating to apparatuses or the like cited in each of the embodiments and modifications described above are incorporated as a part hereof by reference to the extent permitted by law. 1 FIRST LAYER 2 SECOND LAYER 4 MULTILAYER FILM 4S SURFACE 5 BASE 5S SURFACE 10 MULTILAYER-FILM REFLECTIVE MIRROR (REFLECTIVE MIRROR) EX EXPOSURE APPARATUS
	claims	1. A laser patterning apparatus comprising:a stage for supporting an acceptor substrate;a shielding mask on the acceptor substrate and for forming a pattern and attaching to a donor film on one surface thereof;a laser gun at an upper part of the stage for radiating laser light to a portion of the donor film through the pattern of the shielding mask;a pressing member corresponding to a portion of the shielding mask; andan actuator connected to one side of the pressing member and configured to press the pressing member toward the acceptor substrate. 2. The laser patterning apparatus of claim 1, wherein the shielding mask comprises a glass substrate. 3. The laser patterning apparatus of claim 1, wherein the shielding mask comprises:a transfer area corresponding to the donor film; anda non-transfer area corresponding to an outer side of the donor film at an outer side of the transfer area,wherein the pressing member comprises a rim corresponding to at least a part of the non-transfer area. 4. The laser patterning apparatus of claim 3, wherein, with respect to a plane of the stage, an interval is formed between the end of an inner side of the pressing member and the end of an outer side of the transfer area. 5. The laser patterning apparatus of claim 3, wherein, with respect to a plane of the stage, the actuator corresponds to the center between the end of an outer side of the transfer area and the end of an outer side of the shielding mask. 6. The laser patterning apparatus of claim 3, wherein the actuator comprises a plurality of cylinders and is symmetrically disposed with respect to the center of the donor film. 7. The laser patterning apparatus of claim 3, wherein the pressing member comprises a quadrangular rim, andthe actuator comprises four cylinders at four corner portions of the quadrangular rim. 8. A laser patterning apparatus comprising:a stage for supporting an acceptor substrate;a shielding mask for forming a pattern on the acceptor substrate and attaching to a donor film on one surface thereof;a laser gun at an upper part of the stage for radiating laser light to a portion of the donor film through the pattern of the shielding mask;a pressing member for pressing a portion of the shielding mask without interrupting laser radiation of the laser gun; andan actuator connected to one side of the pressing member and configured to press the pressing member toward the acceptor substrate. 9. The laser patterning apparatus of claim 8, wherein the shielding mask comprises a glass substrate. 10. The laser patterning apparatus of claim 8, wherein the shielding mask comprises:a transfer area overlapping the donor film; anda non-transfer area overlapping an outer side of the donor film at an outer side of the transfer area,wherein the pressing member comprises a rim overlapping at least a part of the non-transfer area. 11. The laser patterning apparatus of claim 10, wherein, with respect to a plane of the stage, an interval is formed between the end of an inner side of the pressing member and the end of an outer side of the transfer area. 12. The laser patterning apparatus of claim 10, wherein, with respect to a plane of the stage, the actuator is on the center between the end of an outer side of the transfer area and the end of an outer side of the shielding mask. 13. The laser patterning apparatus of claim 10, wherein the actuator comprises a plurality of cylinders and is symmetrically disposed with respect to the center of the donor film. 14. The laser patterning apparatus of claim 10, wherein the pressing member comprises a quadrangular rim, andthe actuator comprises four cylinders at four corner portions of the quadrangular rim.
	summary
	claims	1. A device for producing electricity, comprising:a substrate;a plurality of stacked material layers above the substrate, the plurality of stacked material layers comprising,a base layer doped with dopants of a first dopant type;an emitter layer doped with dopants of a second dopant type;a window layer having a lattice structure matched to the lattice structure of the emitter layer;wherein each one of the plurality of layers comprises a type III-V semiconductor;a beta particle source for generating beta particles; andwherein the substrate comprises a GaAs substrate, the base layer comprises an n type InGaP layer, the emitter layer comprises a p type InGaP layer, and the window layer comprises a p type InAlP layer. 2. The device of claim 1 further comprising an InGaP back surface reflector layer between the substrate and the base layer. 3. The device of claim 1 wherein the plurality of stacked material layers further comprises a GaAs cap layer disposed between the window layer and the beta particle source, wherein a doping level of the cap layer is about 10^18 ND/cm^3. 4. The device of claim 1 further comprising an intrinsic InGaP layer between the base layer and the emitter layer, wherein a thickness of the intrinsic InGaP layer is between about 1000 and 3000 Angstroms or is between about 50 and 100 Angstroms. 5. The device of claim 1 wherein a bandgap of the window layer is greater than the bandgap of the emitter layer. 6. A device for producing electricity, comprising:a substrate;a plurality of stacked material layers above the substrate, the plurality of stacked material layers comprising,a base layer doped with dopants of a first dopant type;an emitter layer doped with dopants of a second dopant type;a window layer having a lattice structure matched to the lattice structure of the emitter layer;wherein each one of the plurality of layers comprises a type III-V semiconductor;a beta particle source for generating beta particles; andwherein the substrate comprises a GaAs substrate, the base layer comprises a p type InGaP layer, the emitter layer comprises an n type InGaP layer, and the window layer comprises an n type InAlP layer. 7. The device of claim 6 further comprising an InGaP back surface reflector layer between the substrate and the base layer. 8. The device of claim 6 wherein the plurality of stacked material layers further comprises a GaAs cap layer disposed between the window layer and the beta particle source, wherein a doping level of the cap layer is about 10^18 ND/cm^3. 9. The device of claim 6 further comprising an intrinsic InGaP layer between the base layer and the emitter layer, wherein a thickness of the intrinsic InGaP layer is between about 1000 and 3000 Angstroms or is between about 50 and 100 Angstroms. 10. The device of claim 6 wherein a bandgap of the window layer is greater than the bandgap of the emitter layer. 11. A multilayer device for producing electricity, comprising:a beta particle source layer for generating beta particles; andat least three semiconductor layers each having a bandgap substantially similar to a band gap of the other layers, the at least three layers comprising a doped emitter top layer, an undoped intermediate layer and a doped bottom base layer, wherein the emitter and the base layers are doped with opposite-type dopants, and wherein the emitter layer is closer to the beta particle source layer than the base layer; wherein the emitter and the intermediate layers absorb more beta particles than the base layer. 12. The device of claim 11 further comprising a window layer in contact with the emitter layer and a cap layer atop the window layer, wherein the window layer is doped with dopants of the same dopant type as the emitter layer, the window layer having a bandgap larger than the bandgap of the emitter, intermediate and base layers, the window layer having a closely matched lattice to the emitter layer, the cap layer for current collection and for protecting the device from environmental effects.
	claims	1. A method of tracking operational parameters of a drive system including first and second members driven respectively by first and second coupling shafts, the method comprising:providing a first sensor unit on the first coupling shaft, the first sensor unit adapted for wireless communication with a remote processing unit, the first sensor unit including an integrated local processor and local memory;providing a second sensor unit on the second coupling shaft, the second sensor unit adapted for wireless communication with the remote processing unit, the second sensor unit including an integrated local processor and local memory;the first sensor unit operating to acquire and store sensor data in its local memory until the first sensor unit receives a data transmit trigger from the remote processing unit;the second sensor unit operating to acquire and store sensor data in its local memory until the second sensor unit receives a data transmit trigger from the remote processing unit;sending a transmit trigger wirelessly from the remote processing unit to the first sensor unit, the first sensor unit responsively wirelessly transmits sensor data to the remote processing unit;sending a transmit trigger wirelessly from the remote processing unit to the second sensor unit, the second sensor unit responsively wirelessly transmits sensor data to the remote processing unit;wherein the sending of the transmit trigger to the second sensor unit is offset in time from the sending of the transmit trigger to the first sensor unit so as to assure that transmission of sensor data from the first sensor unit to the remote processing unit is completed before transmission of sensor data from the second sensor unit to the remote processing unit takes place. 2. The method of claim 1 wherein the remote processing unit is located spaced apart from, but in a common facility with the first sensor unit and the second sensor unit. 3. The method of claim 1 wherein the first sensor unit operates with an alarm monitor feature active, wherein the first sensor unit monitors acquired sensor data for at least one defined alarm conditions and, if the defined alarm condition is detected the first sensor unit automatically initiates a wireless transmission of an alarm indication to the remote processing unit. 4. A method of tracking operational parameters of a drive system, the method comprising:providing a first sensor unit on a first component of the drive system, the first sensor unit including an integrated local processor;providing a second sensor unit on a second component of the drive system, the second sensor unit including an integrated local processor;detecting a working condition of the drive system;responsive to detection of the working condition,sending a data acquire instruction to the first sensor unit; andsending a data acquire instruction to the second sensor unit, causing both the first and second sensor units to acquire sensor data during a common time period that overlaps with the drive system operating in the working condition. 5. The method of claim 4 wherein the working condition is a speed condition of the drive system. 6. The method of claim 5 wherein the working condition is detected by detecting an increase in speed. 7. A data acquisition system for tracking operational parameters of a drive system, the data acquisition system comprising: a first sensor unit mounted on a rotating component of the drive system, the first sensor unit including an integrated processor and means for wireless communication with a processing unit that is spaced from the first sensor unit, the first sensor unit configured to operate in each of (i) a listening mode during which the first sensor unit awaits instruction from the processing unit, (ii) a data acquisition mode triggered by receipt of a data acquire instruction from the processing unit and during which the first sensor unit acquires sensor data and stores the sensor data in on-board memory and (iii) a data transmit mode triggered by receipt of a data transmits instruction from the processing unit and during which the first sensor unit wirelessly transmits stored sensor data from on-board memory to the processing unit. 8. The data acquisition system of claim 7 wherein the data acquisition mode includes an alarm feature by which the first sensor unit monitors acquired sensor data for one or more alarm conditions and, if an alarm condition is identified, the first sensor unit automatically communicates an alarm notification to the processing unit via wireless transmission. 9. The data acquisition system of claim 7 wherein the processing unit monitors a speed of the drive system and wirelessly transmits the data acquire instruction to the first sensor unit when the speed reaches a certain level.
043472141	summary	BACKGROUND OF THE INVENTION This invention relates to a detection and location apparatus for failed fuel in a reactor utilizing tag gas. Conventionally, there is known a failed fuel detection and location system (FFDL) in which stable tag gas with modified composition, e.g. rare gas, is previously enclosed in the respective fuel pins of a plurality of fuel assemblies disposed inside a reactor, so that the location of a broken fuel pin, if any, is detected by collecting and analyzing tag gas which is released in cover gas when such breakage is occurred. Since the concentration of the tag gas released in cover gas in the reactor, however, is extremely low, it is impossible to determine the composition of the tag gas by directly analyzing the same, according to the existing analysis technique. Therefore, it is necessary to collect the released tag gas securely and to enrich the same to an analyzable concentration. Conventionally, the collection and enrichment of tag gas are achieved by adsorbing the gas with low-temperature activated charcoal cooled to approximately -80.degree. C. or lower and heating it to about 350.degree. C. for removal. In "Design and Manufacture of Gas Tags for FFTF Fuel and Control Assemblies," NUCLEAR TECHNOLOGY, vol. 26, page 472, Aug., (1975) appears a method in which tag gas is collected and enriched by using activated charcoal which is cooled to -79.degree. C. Further, stated in "Proceedings of the Specialists' Meeting on In-Core Instrumentation and Failed Fuel Detection and Location," pages 313 to 317, AECL-5124, May, (1974) is a method in which tag gas is collected by means of activated charcoal cooled to -100.degree. C. and then selectively removed by reheating and sweeping with helium. However, a low-temperature activated-charcoal adsorption apparatus requires large-sized cooling means utilizing a large quantity of liquid nitrogen. Moreover, the selective desorption of the tag gas adsorbed by low-temperature activated charcoal requires extremely difficult selection and control of desorption conditions including temperature, removal time, degree of vacuum, flow rate of sweeping gas, etc., as well as complicated operations. Furthermore, in the low-temperature activated-charcoal adsorption apparatus, impurities such as water contained in various gases may coagulate at an extremely low temperature, tending to cause clog in piping. SUMMARY OF THE INVENTION The object of this invention is to provide a failed fuel detection and location apparatus capable of collecting and enriching tag gas released in cover gas at normal temperature. According to this invention, there is provided a failed fuel detection and location apparatus which comprises means for supplying cover gas containing released tag gas to collection/enrichment means for tag gas, means for collecting tag gas from the sampled cover gas at normal temperature and enriching the tag gas to an analyzable concentration, and means for analyzing the enriched tag gas. Preferably, the collection/enrichment means for tag gas is composed of normal-temperature activated-charcoal adsorption apparatus to adsorb tag gas at normal temperature and heaters to heat their corresponding ambient-temperature activated-charcoal adsorption apparatus to remove the adsorbed tag gas. Alternatively, there may be used a gas separator including a selectively gas-permeable membrane selectively permeating tag gas at normal temperature.
H00009148	summary	BACKGROUND OF THE INVENTION This invention relates to improved apparatus for supporting contactors used in extracting nuclear materials from liquids, and more particularly, to box beam support frames for contactors used for liquid extraction involving nuclear materials. Contactors are centrifugal devices used to extract nuclear materials from liquid solutions. They generally include a housing in which aqueous radioactive materials which include nuclear waste such as transuranic elements (TRUs) are mixed with an organic solvent. The organic solvent extracts the TRUs from the aqueous phase as the two phases are mixed. The two phases are then separated by centrifugal force and removed through separate exit ports. Centrifugal force is created by a rotor in the housing and a motor secured to the top of the housing. Typically, aqueous radioactive waste is processed through a series of contactor stages arranged in a row. The apparatus is isolated to contain radioactivity, and is operated and maintained with mechanical devices such as robotic arms. In known apparatus, the contactors are supported by an L-shaped beam secured near the top of the contactor housing. The beam is supported by vertical posts located both behind the contactor and in front of it. Interconnect pipes through which the liquids flow from one contactor to another bend around the outside of the posts. In order to have sufficient stability with the known design, the posts must be relatively short. A problem with using short posts is that the drain in the bottom of the contactor is then rather close to the ground surface, and is relatively difficult to access. If the posts are made much longer, they become susceptible to unacceptable vibrations. The longer posts cannot be made significantly thicker, however, without interfering with the interconnect pipes. Moreover, the known support system is inconvenient to use because the front posts limit access t a drain valve in the bottom of each contactor stage and other parts of the equipment which must be adjusted by the mechanical devices used to control and maintain the contactors. Thus, there is a need for support systems for contactors which have added stability and improved access for control and maintenance. Accordingly, one object of this invention is to provide new and improved apparatus for supporting contactors used for separating radioactive materials in aqueous solutions. Another object is to provide new and improved apparatus for supporting contactors which is sufficiently stable during operation. Still another object is to provide new and improved apparatus for supporting contactors which permits the contactors to be supported an extended distance from the effective ground surface, for improved access to the drain valves. Yet another object is to provide new and improved apparatus for supporting contactors which provides improved access to drain valves and other parts of the contactors from at least three sides of the contactors. SUMMARY OF THE INVENTION In accordance with one aspect of this invention, apparatus is provided for supporting one or more contactor stages used to separate radioactive materials in aqueous solutions. Each contactor stage has a housing having an internal rotor, a motor secured to the top of the housing for rotating the rotor, and a drain in the bottom of the housing. A plurality of pipes interconnect the contactor stages to each other beneath the motors and in the upper regions of the housings. The support apparatus includes two or more vertical members secured to a ground support, and a horizontally disposed frame member secured to the tops of the vertical members. The frame member may be any suitable shape, but is preferably a rectangular tube having substantially flat, spaced top and bottom surfaces separated by substantially vertical side surfaces. The top and bottom surfaces each have openings through which the contactor housings are secured so that the interconnect pipes are above the frame and the contactor drains are below the frame during use.
040642046	description	The following examples further illustrate various features of the present invention but are intended to in no way limit the scope of the invention which is defined in the appended claims. EXAMPLE I Six hundred gm batches of a graphite flour-pitch matrix and additive blend were prepared. The batches contained 342 gm of pitch, 240 gm of graphite flour having a particle size of less than about 0.04 and 18 gm of an additive. A control batch was prepared wherein the additive was replaced with an additional 18 gm of pitch. For each batch the pitch was heated to a temperature of 200.degree. C, the additive was blended with the heated pitch and the graphite flour was then added. The mixture was then blended for thirty minutes in a sigma blade mixer at a temperature of 200.degree. C and at a mixing rate of 100 rpm. After the batch was cooled, the batch was ground to provide a matrix and additive blend having a particle size in the range of 0.6 to 0.9 mm. The viscosity of the batches was then measured at 175.degree. C and a capillary viscometer. Each of the batches was non-Newtonian showing a decrease in apparent viscosity with increasing shear rate. At a wall shear rate of 100 sec.sup.-1 the apparent viscosities of the batches, with various additives were as set forth below in Table I. About 7 grams of the matrix and additive blend was mixed with about 20 grams of a nuclear fuel material consisting of coated ThC.sub.2 particles and having a particle size in the range of 0.6 to 0.9 mm. Each of the batches was then used to prepare nuclear fuel rods by placing the 27 gram batch (20 grams fuel particles, 7 grams matrix) into a steel mold and compressing the batch at a temperature of 190.degree. C and a pressure of 120 psig. After the nuclear fuel rod was formed the wall shear stress necessary to push each of four consecutive rods out of the same mold cavity with no cleaning of the molds between rods was measured. The average wall shear stress value obtained for each of the additives is indicated below in Table II. Fuel rods fabricated as described above using matrix without additives and fuel rods fabricated using matrix with additives were heat treated to 1800.degree. C in graphite sleeves about 12 inches long, about 0.625 inches inside diameter, and about 0.975 inches outside a diameter with both ends plugged with graphite. It was found that the fuel rods fabricated using matrix without additives adhered to the graphite sleeve, while those fabricated using matrix with additive did not. Table I ______________________________________ Viscosity, Additive Poise ______________________________________ None 2350 Petrolatum (avg. molecular weight-approx. 500) 610 1-Octodecanol 600 Paraffin wax (avg. molecular weight-approx. 700) 770 Oleic acid 920 Stearic acid 660 1-Hexadecanol 800 Stearic acid + paraffin (50:50) 660 Stearic acid + 1-Octadecanol (50:50) 660 1-Octadecylamine 800 ______________________________________ Table II ______________________________________ Additive Shear Stress, PSI ______________________________________ None 1900 Petrolatum 8.71 1-Octadecanol 0.61 Paraffin wax (avg. molecular weight-approx. 31.28 700) Oleic acid 2.11 Stearic acid 0.73 1-Hexadecanol 3.56 Stearic acid + paraffin (50:50) 1.21 Stearic acid + 1-Octadecanol (50:50) 0.95 ______________________________________ EXAMPLE II Further batches of a graphite flour, pitch and additive matrix were prepared having the formulation set forth below in Table III. The apparent viscosity of each of the batches was determined. Each of the matrix batches was then used to prepare fuel rods by the injection method. In this method, about 20 grams of ThC.sub.2 nuclear fuel particles having a particle size in the range of 0.6 to 0.9 mm, were placed in a 15.9 mm diameter cylindrical steel mold. About 7 grams of coarsely ground matrix having a particle size of about 0.6 mm were placed on top of the fuel particles in the mold. The mold was then heated to a temperature of 200.degree. C and a piston was used to force the matrix through the fuel particles to form fuel rods having a length of 61 mm. The average shear stress required to remove four fuel rods from the mold was measured and is reported below in Table III. Table III ______________________________________ Apparent Graph- Viscosity at Average ite Addi- 175.degree. C and Shear Flour- Pitch.sup.1 - tive Additive 100 sec.sup.-1 - Stress- grams grams grams Type poise psig ______________________________________ 180.sup.2 402 18 1-Octadecanol 410 12.6 180.sup.2 384 36 " 420 14.5 198.sup.2 384 18 " 460 14.5 198.sup.2 384 60 " 270 10.6 240.sup.3 324 36 " 380 14.8 240.sup.4 324 36 " 260 2.0 ______________________________________ .sup.1 Obtained from Ashland Oil Co. and identified as A-240 .sup.2 Obtained from Asbury Graphite Corp. and identified as grade 6353 .sup.3 Obtained from Great Lakes Carbon Co. and identified as grade 1089 .sup.4 Obtained from Lonza Ltd. and identified as grade KS-44. By the present invention, a matrix composition with reduced viscosity is provided for the manufacture of nuclear fuel rods intended for use in gas cooled nuclear reactors. The invention also provides a matrix composition that reduces the adhesion of the fuel rods to graphite fuel elements after heating the fuel rods in the fuel element.
	claims	1. An apparatus for decreasing random motions of a levitated diamagnetic cylinder, the apparatus comprising:a vacuum chamber;a plurality of dipole line magnets disposed within the vacuum chamber;a light source disposed within the vacuum chamber;one or more photodetectors disposed within the vacuum chamber;a diamagnetic rod disposed within the vacuum chamber;a first electrode and a second electrode disposed within the vacuum chamber and connected to an external voltage source;a control computer comprising a proportional-integral-derivative (PID) control loop;an input circuit connected to the one or more photodetectors, a differentiator circuit and inputs associated with the PID control loop;a differentiator circuit to calculate the velocity signal; andan electrode voltage drive circuit connected to the first electrode, the second electrode and with inputs coming from the the PID control loop. 2. The apparatus of claim 1, wherein the first electrode and second electrode are an enclosing electrodes design further comprising two semi-circular cylindrical non-magnetic metal shells partially enclosing the diamagnetic rod. 3. The apparatus of claim 1, wherein the first electrode and second electrode are a non-enclosing electrode design further comprising a plurality of semi-circular cylindrical non-magnetic metal shells facing away from the diamagnetic rod towards the dipole line magnets and separated from the dipole line magnets by an insulator wherein the first electrode and the second electrode share a common electrical ground. 4. The apparatus of claim 1, wherein the first electrode and second electrode are a non-enclosing electrode design further comprising a plurality of semi-circular cylindrical non-magnetic metal shells facing away from the diamagnetic rod towards the dipole line magnets and separated from the dipole line magnets by an insulator wherein the dipole line magnets have a separate electrical ground. 5. The apparatus of claim 1, wherein the first electrode and second electrode are an enclosing electrode design further comprising a plurality of flat rectangular non-magnetic metal sheets adjacent to the diamagnetic rod wherein the dipole line magnets have a separate electrical ground. 6. The apparatus of claim 1, wherein the input circuit further comprises a differential amplifier electrically connected to the differential photodetector pair, differentiator, and control computer. 7. The apparatus of claim 6, wherein the output circuit further comprises an electrode voltage drive electrically connected to the control computer and the first electrode and the second electrode. 8. The apparatus of claim 7, wherein the PID controller loop operates on “the velocity error signal”. 9. The apparatus of claim 1, wherein the light source has a broad band spectrum or is monochromatic with wavelength from infrared (IR) to ultra violet (UV). 10. A method for decreasing the effective temperature of a levitated diamagnetic rod trapped between a pair of dipole line magnets, the method comprising:measuring a displacement signal of a diamagnetic rod based on a light source and one or more photodetectors;calculating a velocity signal and a drive polarity, based on the displacement signal, by a differentiator circuit wherein the velocity signal is sent to a proportional-integral-derivative (PID) control loop, wherein the PID control loop generates an output signal;responsive to a positive drive polarity, adjusting a first electrode based on the output signal; andresponsive to a negative drive polarity, adjusting a second electrode based on the output signal. 11. The method in claim 10, further comprises:tuning the PID control loop wherein the PID control loop is connected to an electrode voltage drive, the first electrode, the second electrode, one or more photodetectors, differentiator circuit and an differential amplifier. 12. The method in claim 11, wherein measuring the displacement signal of a diamagnetic rod further comprises:transmitting a light from a light source towards the one or more photodetectors wherein the diamagnetic rod is disposed between the light source and the one or more photodetectors;receiving a displacement signal by the differential amplifier associated with the movement of the diamagnetic rod. 13. The method in claim 10, wherein adjusting the second electrode further comprisesreceiving the output signal from the PDI controller;applying a voltage to the second electrode based on the output signal; andpulling the diamagnetic rod based on the applied voltage. 14. The method of claim 10, wherein adjusting the first electrode further comprisesreceiving the output signal from the PID controller;applying a voltage to the first electrode based on the output signal; andpulling the diamagnetic rod based on the applied voltage. 15. The method in claim 10, further comprising:monitoring the displacement s(t) and velocity v(t) signal from the control loop. 16. A system for decreasing random motions of a levitated diamagnetic cylinder, the system comprising:a vacuum chamber;a plurality of dipole line magnets disposed within the vacuum chamber;a light source disposed within the vacuum chamber;one or more photodetectors disposed within the vacuum chamber;a diamagnetic rod disposed within the vacuum chamber;a first electrode and a second electrode disposed within the vacuum chamber and connected to an external power source;a control computer comprising a proportional-integral-derivative (PID) control loop;an input circuit connected to the one or more photodetectors and inputs associated with the PID control loop;a differentiator circuit to calculate the velocity signal;an electrode drive circuit connected to the first electrode, the second electrode and outputs associated with the PID control loop; anda test server connected to the control computer over a network. 17. The system of claim 16, wherein the test server comprises a database wherein the database is used for storing historical changes of the displacement, velocity and effective temperature of the diamagnetic rod. 18. The system of claim 16 wherein PID controller loop operates on “the velocity error signal”. 19. The system of claim 16, wherein the network further comprises an Ethernet connection and wireless connection. 20. The system of claim 16, wherein the control computer further comprises of a feed-forward loop and a feedback loop.
	description	This application is a National Phase Application of PCT International Application No. PCT/IL2003/000455, International Filing Date Jun. 1, 2003, claiming priority of Israel Patent Application Serial No. 150056, filed Jun. 5, 2002, entitled “Low Pressure Chamber for Scanning Electron Microscopy in a Wet Environment”. The present invention relates to specimen enclosures for scanning electron microscope (SEM) inspection systems and more particularly to fluid specimen enclosures. The following patent documents are believed to represent the current state of the art: U.S. Pat. Nos. 4,071,766; 4,720,633; 5,250,808; 5,326,971; 5,362,964; 5,417,211; 4,705,949; 5,945,672; 6,365,898; 6,130,434; 6,025,592; 5,103,102; 4,596,928; 4,880,976; 4,992,662; 4,720,622; 5,406,087; 3,218,459; 3,378,684; 4,037,109; 4,448,311; 4,115,689; 4,587,666; 5,323,441; 5,811,803; 6,452,177; 5,898,261; 4,618,938; 6,072,178; 4,929,041 and 6,114,695. The present invention seeks to provide apparatus and systems for enabling scanning electron microscope inspection of fluid containing specimens. There is thus provided in accordance with a preferred embodiment of the present invention a specimen enclosure assembly for use in an electron microscope and including a rigid specimen enclosure dish having an aperture and defining an enclosed specimen placement volume, an electron beam permeable, fluid impermeable, cover sealing the specimen placement volume at the aperture from a volume outside the enclosure and a pressure controller communicating with the enclosed specimen placement volume and being operative to maintain the enclosed specimen placement volume at a pressure which exceeds a vapor pressure of a liquid sample in the specimen placement volume and is greater than a pressure of a volume outside the enclosure, whereby a pressure differential across the cover does not exceed a threshold level at which rupture of the cover would occur. In accordance with another preferred embodiment of the present invention the pressure controller includes a passageway communicating with the enclosed specimen placement volume. Preferably, the passageway includes a tube having a lumen whose cross section is sufficiently small as to maintain the pressure, which exceeds the vapor pressure of the liquid sample in the specimen placement volume and is greater than the pressure of the volume outside the enclosure, for a time period of at least 15 minutes. Additionally, the tube communicates with a fluid reservoir. In accordance with yet another preferred embodiment of the present invention the specimen enclosure assembly also includes a liquid ingress and egress assembly permitting supply and removal of liquid from the enclosed specimen placement volume. Preferably, the liquid ingress and egress assembly includes at least two tubes. There is also provided in accordance with another preferred embodiment of the present invention a specimen enclosure assembly for use in an electron microscope and including a rigid specimen enclosure dish having an aperture and defining an enclosed specimen placement volume, an electron beam permeable, fluid impermeable, cover sealing the specimen placement volume at the aperture from a volume outside the enclosure and a liquid ingress and egress assembly permitting supply and removal of liquid from the enclosed specimen placement volume. Preferably, the liquid ingress and egress assembly includes at least two tubes. There is further provided in accordance with yet another preferred embodiment of the present invention a scanning electron microscope assembly including a scanning electron microscope defining an examination volume, a specimen enclosure assembly disposed in the examination volume and including a rigid specimen enclosure dish having an aperture and defining an enclosed specimen placement volume, an election beam permeable, fluid impermeable, cover sealing the specimen placement volume at the aperture from a volume outside the enclosure and a pressure controller communicating with the enclosed specimen placement volume and being operative to maintain the enclosed specimen placement volume at a pressure which exceeds a vapor pressure of a liquid sample in the specimen placement volume and is greater than a pressure of a volume outside the enclosure, whereby a pressure differential across the cover does not exceed a threshold level at which rupture of the cover would occur. In accordance with another preferred embodiment of the present invention the pressure controller includes a passageway communicating with the enclosed specimen placement volume. Preferably, the passageway includes a tube having a lumen whose cross section is sufficiently small as to maintain the pressure, which exceeds the vapor pressure of the liquid sample in the specimen placement volume and is greater than the pressure of the volume outside the enclosure, for a time period of at least 15 minutes. Additionally, the tube communicates with a fluid reservoir. In accordance with yet another preferred embodiment of the present invention the scanning electron microscope also includes a liquid ingress and egress assembly permitting supply and removal of liquid from the enclosed specimen placement volume. Preferably, the liquid ingress and egress assembly includes at least two tubes. There is also provided in accordance with yet another preferred embodiment of the present invention a specimen enclosure assembly for use in an electron microscope and including a fluid reservoir, a plurality of rigid specimen enclosure dishes, each having an aperture and defining an enclosed specimen placement volume, the plurality of rigid specimen enclosure dishes communicating with the fluid reservoir, an electron beam permeable, fluid impermeable, cover sealing each of the specimen placement volumes at the apertures from a volume outside each of the enclosures, and a pressure controller communicating with the fluid reservoir and being operative to maintain the enclosed specimen placement volumes at a pressure which exceeds a vapor pressure of a liquid sample in the specimen placement volumes and is greater than a pressure of a volume outside the fluid reservoir, whereby a pressure differential across the covers does not exceed a threshold level at which rupture of the covers would occur. In accordance with another preferred embodiment of the present invention the pressure controller includes a passageway. Preferably, the passageway includes a tube having a lumen whose cross section is sufficiently small as to maintain the pressure, which exceeds the vapor pressure of the liquid sample in the specimen placement volume and is greater than the pressure of the volume outside the plurality of enclosures, for a time period of at least 15 minutes. Additionally, the tube communicates with the fluid reservoir. Additionally or alternatively, the specimen enclosure assembly also includes a liquid ingress and egress assembly permitting supply and removal of liquid from the enclosed specimen placement volume. Preferably, the liquid ingress and egress assembly includes at least two tubes. Reference is now made to FIG. 1, which is a simplified sectional illustration of a specimen enclosure assembly 100 constructed and operative in accordance with a preferred embodiment of the present invention. As seen in FIG. 1, the specimen enclosure assembly 100 comprises a specimen enclosure dish 102 seated in a container 104. Specimen enclosure dish 102 preferably is formed of a ting 106 having a generally central aperture 108. Ring 106 is preferably formed of PMMA (polymethyl methacrylate), such as Catalog No. 692106001000, commercially available from Irpen S. A. of Barcelona, Spain, and preferably defines a specimen placement enclosure with a volume of approximately 20 microliters and a height of approximately 2 mm. The specimen enclosure dish 102 is seated in a recess 109 formed in a top of the container 104. An O-ring 110 is preferably disposed between ring 106 and an interior surface 112 of container 104. An electron beam permeable, fluid impermeable, cover 114 is placed on specimen enclosure dish 102 against and over central aperture 108. The electron beam permeable, fluid impermeable, cover 114 preferably comprises a polyimide membrane, such as Catalog No. LWN00020, commercially available from Moxtek Inc. of Orem, Utah, U.S.A. Cover 114 is adhered, as by an adhesive, to a mechanically supporting grid 116, which is not shown to scale, such as Catalog No. 2007N or Catalog No. 2005N, which is commercially available from Structure Probe Inc. of 569 East Gay Street, West Chester, Pa., U.S.A. A preferred adhesive is commercially available from Norland Products Inc. of Cranbury, N.J., U.S.A., identified by Catalog No. NOA61. The electron beam permeable, fluid impermeable, cover 114 is also adhered to ring 106, preferably by an adhesive, such as Catalog No. NOA61, commercially available from Norland Products Inc. of Cranbury, N.J., U.S.A. A top element 118 is provided to retain the specimen enclosure dish 102 in container 104. Top element 118 is preferably formed as a ring having a generally central aperture 122 and is attached to container 104 by any conventional means, such as by screws (not shown). A specimen 123, typically containing cells 124 in a liquid medium 125, is typically located within the specimen enclosure dish 102, lying against the electron beam permeable, fluid impermeable, cover 114. Examples of specimens containing liquid may include cell cultures, blood and bacteria. It is noted that the liquid 125 in specimen 123 does not flow out of the specimen enclosure dish 102 due to surface tension. Container 104 defines a fluid reservoir 126 containing at least one fluid. The fluid preferably comprises a liquid 128, such as water or specimen liquid. The liquid 128 in fluid reservoir 126 is provided to supply the specimen enclosure dish 102 with vapor, such as water vapor, so as to prevent evaporation of the specimen liquid 125 by permitting vapor flow into specimen enclosure dish 102 through aperture 108. A pressure controller assembly 130 is operative to maintain the specimen enclosure dish 102, during microscopic inspection, generally over a time duration in a range of several minutes to several hours, typically a time period of at least 15 minutes, at a pressure which exceeds a vapor pressure of the specimen 123 and is greater than a pressure of a volume outside the specimen enclosure assembly 100, whereby a pressure differential across the electron beam permeable, fluid impermeable, cover 114 does not exceed a threshold level at which rupture of cover 114 would occur. The pressure controller assembly 130 preferably comprises a tube 132, such as Catalog No. MF34G-5 or Catalog No. MF28G-5, commercially available from World Precision Instruments Inc. of 175 Sarasota Center Boulevard, Sarasota, Fla., U.S.A., and a tube housing 134. Tube 132 is inserted into an aperture 136 formed in a wall of container 104 above a surface of the liquid 128 in the fluid reservoir 126. Tube 132 is sealingly attached to the container wall so that fluid flows from container 104 only through the tube 132. It is a particular feature of the present invention that the tube 132 has a lumen with a cross section sufficiently small, preferably of a diameter in a range of 50 to 150 micrometers, to provide for relatively slow dissipation of pressure from the specimen enclosure assembly 100. Reference is now made to FIG. 2, which is a simplified sectional illustration of a specimen enclosure assembly 200 constructed and operative in accordance with another preferred embodiment of the present invention. As seen in FIG. 2, the specimen enclosure assembly 200 comprises a specimen enclosure dish 202 seated in a container 204. Specimen enclosure dish 202 preferably is formed of a ring 206 having a generally central aperture 208. Ring 206 is preferably formed of PMMA (polymethyl methacrylate), such as Catalog No. 692106001000, commercially available from Irpen S. A. of Barcelona, Spain, and preferably defines a specimen placement enclosure with a volume of approximately 20 microliters and a height of approximately 2 mm. The specimen enclosure dish 202 is seated in a recess 209 formed in a top of the container 204. An O-ring 210 is preferably disposed between ring 206 and an interior surface 212 of container 204. An electron beam permeable, fluid impermeable, cover 214 is placed on specimen enclosure dish 202 against and over central aperture 208. The electron beam permeable, fluid impermeable, cover 214 preferably comprises a polyimide membrane, such as Catalog No. LWN00020, commercially available from Moxtek Inc. of Orem, Utah, U.S.A. Cover 214 is adhered, as by an adhesive, to a mechanically supporting grid 216, which is not shown to scale, such as Catalog No. 2007N or Catalog No. 2005N, which is commercially available from Structure Probe Inc. of 569 East Gay Street, West Chester, Pa., U.S.A. A preferred adhesive is commercially available from Norland Products Inc. of Cranbury, N.J., U.S.A., identified by Catalog No. NOA61. The electron beam permeable, fluid impermeable, cover 214 is also adhered to ring 206, preferably by an adhesive, such as Catalog No. NOA61, commercially available from Norland Products Inc. of Cranbury, N.J., U.S.A. A top element 218 is provided to retain the specimen enclosure dish 202 in container 204. Top element 218 is preferably formed of as a ring having a generally central aperture 222 and is attached to container 204 by any conventional means, such as by screws (not shown). A specimen 223, typically containing cells 224 in a liquid medium 225, is typically located within the specimen enclosure dish 202, lying against the electron beam permeable, fluid impermeable, cover 214. Examples of specimens containing liquid may include cell cultures, blood and bacteria. Container 204 contains at least one fluid. The fluid preferably comprises a liquid 228, such as water or specimen liquid. Liquid 228 typically fills container 204 and specimen enclosure dish 202, as shown in FIG. 2, or fills part of container 204, similar to reservoir 126 shown in FIG. 1. The liquid 228 in container 204 is provided to supply the specimen enclosure dish 202 with vapor, such as water vapor, so as to prevent evaporation of the specimen liquid 225. A fluid reservoir 230 contains at least one fluid in addition to the fluid contained in the specimen enclosure assembly 200. The fluid preferably comprises a liquid 232, such as water or specimen liquid. Preferably, fluid reservoir 230 has a larger internal volume than specimen enclosure assembly 200. A lid 234 covers fluid reservoir 230 and is attached to fluid reservoir 230 by any conventional means, such as by screws (not shown). The liquid 232 in fluid reservoir 230 is provided to supply the specimen is enclosure assembly 200 with additional vapor, such as water vapor, in addition to the container liquid 228, so as to Anther prevent evaporation of the specimen liquid 225, by permitting vapor flow into specimen enclosure dish 202 through a fluid passageway 240. The fluid passageway 240 comprises a conduit 242 having a first end portion and a second end portion, designated by reference numerals 244 and 246 respectively. First end portion 244 is inserted into an aperture 248 formed in a wall of container 204 and second end portion 246 is inserted into an aperture 250 formed in a wall of fluid reservoir 230. A pressure controller assembly 260 is operative to maintain the specimen enclosure dish 202, during microscopic inspection, generally over a time duration in a range of several minutes to several hours, typically a time period of at least 15 minutes, at a pressure which exceeds a vapor pressure of the specimen 223 and is greater than a pressure of a volume outside the specimen enclosure assembly 200, whereby a pressure differential across the electron beam permeable, fluid impermeable, cover 214 does not exceed a threshold level at which rupture of cover 214 would occur. Additionally, the fluid in fluid reservoir 230 is provided to further maintain the pressure within the specimen enclosure assembly 200, as described hereinabove, during microscopic inspection. The pressure controller assembly 260 preferably comprises a tube 262, such as Catalog No. MF34G-5 or Catalog No. M28G-5, commercially available from World Precision Instruments Inc. of 175 Sarasota Center Boulevard, Sarasota, Fla., U.S.A., and a tube housing 264. Tube 262 is inserted into an aperture 266 formed in the fluid reservoir wall above a surface of the liquid 232 in the fluid reservoir 230. Tube 262 is sealingly attached to the fluid reservoir wall so that fluid flows from fluid reservoir 230 only through the tube 262 and fluid passageway 240. It is a particular feature of the present invention that the tube 262 has a lumen with a cross section sufficiently small, preferably of a diameter in a range of 50 to 150 micrometers, to provide for relatively slow dissipation of pressure from the fluid reservoir 230. Reference is now made to FIG. 3, which is a simplified sectional illustration of a specimen enclosure assembly 300 constructed and operative in accordance with yet another preferred embodiment of the present invention. As seen in FIG. 3, the specimen enclosure assembly 300 comprises a specimen enclosure dish 302 seated in a container 304. Specimen enclosure dish 302 preferably is formed of a ring 306 having a generally central aperture 308. Ring 306 is preferably formed of PE (polymethyl methacrylate), such as Catalog No. 692106001000, commercially available from Irpen S. A. of Barcelona, Spain, and preferably defines a specimen placement enclosure with a volume of approximately 20 microliters and a height of approximately 2 mm. The specimen enclosure dish 302 is seated in a recess 309 formed in a top of the container 304. An O-ring 310 is preferably disposed between ring 306 and an interior surface 312 of container 304. An electron beam permeable, fluid impermeable, cover 314 is placed on specimen enclosure dish 302 against and over central aperture 308. The electron beam permeable, fluid impermeable, cover 314 preferably comprises a polyimide membrane, such as Catalog No. LWN00020, commercially available from Moxtek Inc. of Orem, Utah, U.S.A. Cover 314 is adhered, as by an adhesive, to a mechanically supporting grid 316, which is not shown to scale, such as Catalog No. 2007N or Catalog No. 2005N, which is commercially available from Structure Probe Inc. of 569 East Gay Street, West Chester, Pa., U.S. A preferred adhesive is commercially available from Norland Products Inc. of Cranbury, N.J., U.S.A., identified by Catalog No. NOA61 The electron beam permeable, fluid impermeable, cover 314 is also adhered to ring 306, preferably by an adhesive, such as Catalog No. NOA61, commercially available from Norland Products Inc. of Cranbury, N.J., U.S.A. A top element 318 is provided to retain the specimen enclosure dish 302 in container 304. Top element 318 is preferably formed as a ring having a generally central aperture 372 and is attached to container 304 by any conventional means, such as by screws (not shown). A specimen 323, typically containing cells 324 in a liquid medium 325, is typically located within the specimen enclosure dish 302, lying against the electron beam permeable, fluid impermeable, cover 314. Examples of specimens containing liquid may include cell cultures, blood and bacteria. Container 304 contains a liquid 328, such as water or specimen liquid, filling container 304 and the specimen enclosure dish 302. A fluid reservoir 330 contains at least one fluid in addition to the fluid contained in the specimen enclosure assembly 300. The fluid preferably comprises a liquid 332, such as water or specimen liquid. Preferably, fluid reservoir 330 has a larger internal volume than specimen enclosure assembly 300. A lid 334 covers fluid reservoir 330 and is attached to fluid reservoir 330 by any conventional means, such as by screws (not shown). The liquid 332 in fluid reservoir 330 is provided to supply the specimen enclosure assembly 300 with additional vapor, such as water vapor, in addition to the container liquid 328, so as to further prevent evaporation of the specimen liquid 325, by permitting vapor flow into specimen enclosure dish 302 through a fluid passageway 340. The fluid passageway 340 comprises a conduit 342 having a first end portion and a second end portion, designated by reference numerals 344 and 346 respectively. First end portion 344 is inserted into an aperture 348 formed in a wall of container 304 and second end portion 346 is inserted into an aperture 350 formed in a wall of fluid reservoir 330. A pressure controller assembly 360 is operative to maintain the specimen enclosure dish 302, during microscopic inspection, generally over a time duration in a range of several minutes to several hours, typically a time period of at least 15 minutes, at a pressure which exceeds a vapor pressure of the specimen 323 and is greater than a pressure of a volume outside the specimen enclosure assembly 300, whereby a pressure differential across the electron beam permeable, fluid impermeable, cover 314 does not exceed a threshold level at which rupture of cover 314 would occur, Additionally, the fluid in fluid reservoir 330 is provided to further maintain the pressure within the specimen enclosure assembly 300, as described hereinabove, during microscopic inspection. The pressure controller assembly 360 preferably comprises a tube 362, such as Catalog No. MF34(G-5 or Catalog No. MF28G-5, commercially available from World Precision Instruments Inc. of 175 Sarasota Center Boulevard, Sarasota, Fla., U.S.A., and a tube housing 364. Tube 362 is inserted into an aperture 366 formed in the fluid reservoir wall above a surface of the liquid 332 in the fluid reservoir 330. Tube 362 is sealingly attached to the fluid reservoir wall so that fluid flows from fluid reservoir 330 only through the tube 362 and fluid passageway 340. It is a particular feature of the present invention that the tube 362 has a lumen with a cross section sufficiently small, preferably with a diameter in a range of 50 to 150 micrometers, to provide for relatively slow dissipation of pressure from the fluid reservoir 330. Specimen enclosure assembly 300 is preferably provided with a liquid ingress and egress assembly 370 so as to permit supply and removal of liquid from the specimen enclosure assembly 300 to an environment outside a SEM enclosure wall, here designated by reference numeral 372. Liquid ingress and egress assembly 370 preferably comprises an inlet conduit 374 and an outlet conduit 376 attached to specimen enclosure assembly 300. Reference is now made to FIG. 4, which is a simplified sectional illustration of a multiple specimen enclosure assembly constructed and operative in accordance with a preferred embodiment of the present invention. As seen in FIG. 4, the multiple specimen enclosure assembly is comprised of a plurality of individual specimen enclosure assemblies 400. Each specimen enclosure assembly 400 comprises a specimen enclosure dish 402 seated in a container 404. Specimen enclosure dish 402 preferably is formed of a ring 406 having a generally central aperture 408. Ring 406 is preferably formed of PEA (polymethyl methacrylate), such as Catalog No. 692106001000, commercially available from Irpen S. A. of Barcelona, Spain, and preferably defines a specimen placement enclosure with a volume of approximately 20 microliters and a height of approximately 2 mm. The specimen enclosure dish 402 is seated in a recess 409 formed in a top of the container 404 An O-ring 410 is preferably disposed between ring 406 and an interior surface 412 of container 404. An electron beam permeable, fluid impermeable, cover 414 is placed on specimen enclosure dish 402 against and over central aperture 408. The electron beam permeable, fluid impermeable, cover 414 preferably comprises a polyimide membrane, such as Catalog No. LWN00020, commercially available from Moxtek Inc. of Orem, Utah, U.S.A. Cover 414 is adhered, as by an adhesive, to a mechanically supporting grid 416, which is not shown to scale, such as Catalog No. 2007N or Catalog No. 2005N, which is commercially available from Structure Probe Inc. of 569 East Gay Street, West Chester, Pa., U.S.A. A preferred adhesive is commercially available from Norland Products Inc. of Cranbury, N.J., U.S.A., identified by Catalog No. NOA61. The electron beam permeable, fluid impermeable, cover 414 is also adhered to ring 406, preferably by an adhesive, such as Catalog No. NOA61, commercially available from Norland Products Inc. of Cranbury, N.J., U.S.A. A top element 418 is provided to retain the specimen enclosure dish 402 in container 404. Top element 418 is preferably formed as a ring having a generally central aperture 422 and is attached to container 404 by any conventional means, such as by screws (not shown). A specimen 423, typically containing cells 424 in a liquid medium 425, is typically located within the specimen enclosure dish 402, lying against the electron beam permeable, fluid impermeable, cover 414. Examples of specimens containing liquid may include cell cultures, blood and bacteria. It is noted that the liquid 425 in specimen 423 does not flow out of the specimen enclosure dish 402 due to surface tension. The multiple specimen enclosure assembly, as shown in FIG. 4, also comprises a fluid reservoir 430 containing at least one fluid. The fluid preferably comprises a liquid 432, such as water or specimen liquid. The liquid 432 in fluid reservoir 430 is provided to supply each specimen enclosure assembly 400 with vapor, such as water vapor, so as to prevent evaporation of the specimen liquid 425 by permitting vapor flow into individual specimen enclosure assemblies 400 through apertures 434 formed on a bottom surface of containers 404. A lid 440 defines an array of specimen enclosure assembly support locations 442. Each specimen enclosure support location 442 is preferably defined by a recess 444 arranged to receive specimen enclosure assemblies 400. Specimen enclosure assemblies 400 are sealingly attached to lid 440, by any conventional means, such as by screws (not shown), so as to prevent dissipation of fluid from lid 440. Lid 440 covers the fluid reservoir 430 and is attached to fluid reservoir 430 by any conventional means, such as by screws (not shown). A pressure controller assembly 460 is operative to maintain, during microscopic inspection, generally over a time duration in a range of several minutes to several hours, typically a time period of at least 15 minutes, each specimen enclosure dish 402 at a pressure which exceeds a vapor pressure of the liquid specimen 423 and is greater than a pressure of a volume outside the specimen enclosure assembly 400, whereby a pressure differential across the electron beam permeable, fluid impermeable, cover 414 does not exceed a threshold level at which rupture of cover 414 would occur. The pressure controller assembly 460 preferably comprises a tube 462, such as Catalog No. MF34G-5 or Catalog No. MF28G-5, commercially available from World Precision Instruments Inc. of 175 Sarasota Center Boulevard, Sarasota, Fla., U.S.A., and a tube housing 464. Tube 462 is inserted into an aperture 466 formed in a wall of fluid reservoir 430 above a surface of the liquid 432. Tube 462 is sealingly attached to the fluid reservoir wall so that fluid flows from fluid reservoir 430 only through the tube 462. It is a particular feature of the present invention that the tube 462 has a lumen with a cross section sufficiently small, preferably with a diameter in a range of 50 to 150 micrometers, to provide for relatively slow dissipation of pressure from the specimen enclosure assembly 400. Reference is now made to FIG. 5, which is a simplified pictorial and sectional illustration of a SEM including the specimen enclosure assembly of FIG. 1. As seen in FIG. 5, the specimen enclosure assembly, here designated by reference numeral 500, is engaged with a pressure controller assembly, here designated by reference numeral 502. Specimen enclosure assembly 500 and pressure controller assembly 502 are shown positioned on a stage 504 of a SEM 506. Reference is now made to FIG. 6, which is a simplified pictorial and sectional illustration of a SEM including the specimen enclosure assembly of FIG. 2. As seen in FIG. 6, the specimen enclosure assembly, here designated by reference numeral 600, is engaged with a fluid reservoir, here designated by reference numeral 602, via a fluid passageway 604. A pressure controller assembly, here designated by reference numeral 608, is engaged with fluid reservoir 602. Specimen enclosure assembly 600 and fluid reservoir 602 are shown positioned on a stage 610 of a SEM 612. Reference is now made to FIG. 7, which is a simplified pictorial and sectional illustration of a SEM including the specimen enclosure assembly of FIG. 3. As seen in FIG. 7, the specimen enclosure assembly, here designated by reference numeral 700, is engaged with a fluid reservoir, here designated by reference numeral 702, via a fluid passageway 704. A pressure controller assembly, here designated by reference numeral 708, is engaged with fluid reservoir 702. Specimen enclosure assembly 700 and fluid reservoir 702 are shown positioned on a stage 710 of a SEM 712. An inlet conduit 720 and an outlet conduit 722 are attached to the specimen enclosure assembly 700. Reference is now made to FIG. 8, which is a simplified pictorial and sectional illustration of a SEM including the multiple specimen enclosure assembly of FIG. 4. As seen in FIG. 8, the multiple specimen enclosure assembly, here designated by reference numeral 800, is shown positioned on a stage 802 of a SEM 804. A pressure controller assembly, here designated by reference numeral 808, is engaged with the multiple specimen enclosure assembly 800. It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove. Rather the scope of the present invention includes both combinations and subcombinations of the various features described hereinabove as well as modifications and variations thereof as would occur to a person of skill in the art upon reading the foregoing specification and which are not in the prior art.
054460751	abstract	Apparatus (10) for providing manipulative physical therapy includes a first mass (14) of a putty including a reaction product of siloxane with a boron- or tin-containing compound and a normal polysiloxane. At least one additional mass (18-32) of the putty is provided to the patient, the additional mass adaptable to be manually combined by the patient with the first mass (14) until a uniform color is achieved in the combined mass (38). Preferably, a plurality of additional masses (18-32) having a variety of colors are provided for successive combination with the combined mass. The apparatus provides a means by which the progress of manipulative physical therapy may be monitored, as a uniform color in the combined mass will be achieved only after extensive manipulation.
	claims	1. A radiation therapy treatment planning machine for use with a multileaf collimator, said machine comprising:a Multileaf-Collimator-Position-Calculation-Unit that generates multileaf collimator leaf positions as a time series;a Motion-Speed-Calculating-Unit that calculates leaf motion speed based on the generated time series leaf positions;a Motion-Speed-Limit-Establishing-Unit that establishes a motion speed limit of the leaves; anda Motion-Display-Unit that indicates leaf motion information and indicates the motion information of an area where the calculated motion speed exceeds the established motion speed limit. 2. The radiation therapy treatment planning machine according to claim 1, wherein said Motion-Speed-Limit-Establishing-Unit comprises a Motion-Speed-Limit-Inputting-Unit that inputs a motion speed limit of the leaves as the established motion speed limit. 3. The radiation therapy treatment planning machine according to claim 2, further comprising:a Motion-Acceleration-Calculating-Unit that calculates leaf motion acceleration based on the time series leaf positions generated by said Multileaf-Collimator-Position-Calculation-Unit; anda Motion-Acceleration-Limit-Inputting-Unit that inputs a motion acceleration limit of the leaves,wherein said Motion-Display-Unit indicates the motion information of an area where the calculated motion acceleration exceeds the inputted acceleration limit. 4. The radiation therapy treatment planning machine according to claim 1, wherein said Motion-Speed-Limit-Establishing-Unit comprises a Motion-Speed-Limit-Setting-Unit that sets a predetermined motion speed limit of the leaves as the established motion speed limit. 5. The radiation therapy treatment planning machine according to claim 4, further comprising:a Motion-Acceleration-Calculating-Unit that calculates leaf motion acceleration based on the time series leaf positions generated by said Multileaf-Collimator-Position-Calculation-Unit; anda Motion-Acceleration-Limit-Setting-Unit that sets a predetermined motion acceleration limit of the leaves,wherein said Motion-Display-Unit indicates the motion information of an area where the calculated motion acceleration exceeds the predetermined set acceleration limit. 6. The radiation therapy treatment planning machine according to claim 1, further comprising:a Motion-Acceleration-Calculating-Unit that calculates leaf motion acceleration based on the time series leaf positions generated by said Multileaf-Collimator-Position-Calculation-Unit,wherein said Motion-Display-Unit indicates the motion information of an area where the calculated motion acceleration exceeds a motion acceleration limit. 7. A radiation therapy treatment planning machine for use with a multileaf collimator, said machine comprising:a Multileaf-Collimator-Position-Calculation-Unit that generates multileaf collimator leaf positions as a time series;a Motion-Speed-Calculating-Unit that calculates leaf motion speed based on the generated time series leaf positions;a Motion-Speed-Limit-Establishing-Unit that establishes a motion speed limit of the leaves; anda Leaf-Position-Correction-Unit that corrects the leaf positions of an area, where the calculated motion speed exceeds the established motion speed limit, such that the leaf motion speed is equal to or less than the established motion speed limit. 8. The radiation therapy treatment planning machine according to claim 7, wherein said Motion-Speed-Limit-Establishing-Unit comprises a Motion-Speed-Limit-Inputting-Unit that inputs a motion speed limit of the leaves as the established motion speed limit. 9. The radiation therapy treatment planning machine according to claim 8, wherein the leaf positions are corrected toward a direction to widen the radiation field shape when said Leaf-Position-Correction-Unit corrects the leaf positions of an area where the calculated motion speed exceeds the inputted motion speed limit such that the leaf motion speed is equal to or less than the inputted motion speed limit. 10. The radiation therapy treatment planning machine according to claim 9, further comprising:a Motion-Acceleration-Calculating-Unit that calculates leaf motion acceleration based on the leaf positions corrected by said Leaf-Position-Correction-Unit; anda Motion-Acceleration-Limit-Inputting-Unit that inputs a motion acceleration limit of the leaves,wherein said Leaf-Position-Correction-Unit corrects the leaf positions of an area, where the calculated motion acceleration exceeds the inputted acceleration limit, such that the leaf motion acceleration is equal to or less than the inputted acceleration limit. 11. The radiation therapy treatment planning machine according to claim 8, wherein the leaf positions are corrected toward a direction to narrow the radiation field shape when said Leaf-Position-Correction-Unit corrects the leaf positions of an area where the calculated motion speed exceeds the inputted motion speed limit such that the leaf motion speed is equal to or less than the inputted motion speed limit. 12. The radiation therapy treatment planning machine according to claim 11, further comprising:a Motion-Acceleration-Calculating-Unit that calculates leaf motion acceleration based on the leaf positions corrected by said Leaf-Position-Correction-Unit; anda Motion-Acceleration-Limit-Inputting-Unit that inputs a motion acceleration limit of the leaves,wherein said Leaf-Position-Correction-Unit corrects the leaf positions of an area, where the calculated motion acceleration exceeds the inputted acceleration limit, such that the leaf motion acceleration is equal to or less than the inputted acceleration limit. 13. The radiation therapy treatment planning machine according to claim 8, further comprising:a Motion-Acceleration-Calculating-Unit that calculates leaf motion acceleration based on the leaf positions corrected by said Leaf-Position-Correction-Unit; anda Motion-Acceleration-Limit-Inputting-Unit that inputs motion acceleration limit of the leaves,wherein said Leaf-Position-Correction-Unit corrects the leaf positions of an area, where the calculated motion acceleration exceeds the inputted acceleration limit, such that the leaf motion acceleration is equal to or less than the inputted acceleration limit. 14. The radiation therapy treatment planning machine according to claim 7, wherein said Motion-Speed-Limit-Establishing-Unit comprises a Motion-Speed-Limit-Setting-Unit that sets a predetermined motion speed limit of the leaves as the established motion speed limit. 15. The radiation therapy treatment planning machine according to claim 14, wherein the leaf positions are corrected toward a direction to widen the radiation field shape when said Leaf-Position-Correction-Unit corrects the leaf positions of an area where the calculated motion speed exceeds the predetermined set motion speed limit such that the leaf motion speed is equal to or less than the predetermined set motion speed limit. 16. The radiation therapy treatment planning machine according to claim 15, further comprising:a Motion-Acceleration-Calculating-Unit that calculates leaf motion acceleration based on the leaf positions corrected by said Leaf-Position-Correction-Unit; anda Motion-Acceleration-Limit-Setting-Unit that sets a motion acceleration limit of the leaves,wherein said Leaf-Position-Correction-Unit corrects the leaf positions of an area, where the calculated motion acceleration exceeds the predetermined set acceleration limit, such that the leaf motion acceleration is equal to or less than the predetermined set acceleration limit. 17. The radiation therapy treatment planning machine according to claim 14, wherein the leaf positions are corrected toward a direction to narrow the radiation field shape when said Leaf-Position-Correction-Unit corrects the leaf positions of an area where the calculated motion speed exceeds the predetermined set motion speed limit such that the leaf motion speed is equal to or less than the predetermined set motion speed limit. 18. The radiation therapy treatment planning machine according to claim 17, further comprising:a Motion-Acceleration-Calculating-Unit that calculates leaf motion acceleration based on the leaf positions corrected by said Leaf-Position-Correction-Unit; anda Motion-Acceleration-Limit-Setting-Unit that sets a motion acceleration limit of the leaves,wherein said Leaf-Position-Correction-Unit corrects the leaf positions of an area, where the calculated motion acceleration exceeds the predetermined set acceleration limit, such that the leaf motion acceleration is equal to or less than the predetermined set acceleration limit. 19. The radiation therapy treatment planning machine according to claim 14, further comprising:a Motion-Acceleration-Calculating-Unit that calculates leaf motion acceleration based on the leaf positions corrected by said Leaf-Position-Correction-Unit; anda Motion-Acceleration-Limit-Setting-Unit that sets a predetermined motion acceleration limit of the leaves,wherein said Leaf-Position-Correction-Unit corrects the leaf positions of an area, where the calculated motion acceleration exceeds the predetermined set acceleration limit, such that the leaf motion acceleration is equal to or less than the predetermined set acceleration limit. 20. A radiation therapy treatment planning machine for use with a multileaf collimator, said machine comprising:a Multileaf-Collimator-Position-Calculation-Unit that generates multileaf collimator leaf positions as a time series;a Motion-Acceleration-Calculating-Unit that calculates leaf motion acceleration based on the generated time series leaf positions;a Motion-Acceleration-Limit-Establishing-Unit that establishes a motion acceleration limit of the leaves; anda Motion-Display-Unit that indicates leaf motion information of an area where the calculated motion acceleration exceeds the established acceleration limit. 21. The radiation therapy treatment planning machine according to claim 20, wherein said Motion-Acceleration-Limit-Establishing-Unit comprises a Motion-Acceleration-Limit-Inputting-Unit that inputs a motion acceleration limit of the leaves as the established motion acceleration limit. 22. The radiation therapy treatment planning machine according to claim 20, wherein said Motion-Acceleration-Limit-Establishing-Unit comprises a Motion-Acceleration-Limit-Setting-Unit that sets a predetermined motion acceleration limit of the leaves as the established motion acceleration limit. 23. A radiation therapy treatment planning machine for use with a multileaf collimator, said machine comprising:a Multileaf-Collimator-Position-Calculation-Unit that generates multileaf collimator leaf positions as a time series;a Motion-Acceleration-Calculating-Unit that calculates leaf motion acceleration based on the generated time series leaf positions;a Motion-Acceleration-Limit-Establishing-Unit that establishes a motion acceleration limit of the leaves; anda Leaf-Position-Correction-Unit that corrects the leaf positions of an area, where the calculated motion acceleration exceeds the established motion acceleration limit, such that the leaf motion acceleration is equal to or less than the established motion acceleration limit. 24. The radiation therapy treatment planning machine according to claim 23, wherein said Motion-Acceleration-Limit-Establishing-Unit comprises a Motion-Acceleration-Limit-Inputting-Unit that inputs a motion acceleration limit of the leaves as the established motion acceleration limit. 25. The radiation therapy treatment planning machine according to claim 23, wherein said Motion-Acceleration-Limit-Establishing-Unit comprises a Motion-Acceleration-Limit-Setting-Unit that sets a predetermined motion acceleration limit of the leaves as the established motion acceleration limit.
046876308	claims	1. In a nuclear fuel assembly having at least one control rod guide thimble and a top nozzle, said guide thimble including an upper extension member, said top nozzle including a lower adapter plate supported on said guide thimble with said extension member extending above said lower adapter plate, an upper hold-down plate having a passageway slidably receiving an upper end portion of said extension member and at least one hold-down spring disposed between said plates so as to bias said upper hold-down plate for movement upwardly along said extension member in a direction away from said lower adapter plate, an improved joint structure flexibly interconnecting said hold-down plate with said upper end portion of said guide thimble upper extension member, said joint structure comprising: (a) first overlapping means on said upper hold-down plate at side passageway thereof; and (b) second overlapping means on said upper end portion of said guide thimble extension member; (c) said first and second overlapping means being respectively disposed to interfere with one another so as to limit said upward movement of said hold-down plate along said guide thimble extension member in the direction away from said lower adapter plate; (d) at least one of said first and second overlapping means being resiliently yieldable so as to bias said hold-down plate in an opposite direction toward said lower adapter plate and against the bias of said hold-down spring for absorbing the energy of an impulse load applied to said hold-down plate in the direction upwardly along said guide thimble extension member so as to thereby limit transfer of said load to said guide thimble extension member. a recess defined on said upper end portion of said guide thimble extension member; and a spring member fitted on said upper end portion within said recess thereon and extending outwardly therefrom so as to overlie said internal ledge in said hold-down plate passageway. (a) an internal annular ledge defined on said upper hold-down plate within said passageway at a lower portion thereof so as to surround said upper end portion of said extension member; (b) means defining an annular recess on said upper end portion of said guide thimble extension member; and (c) an annular spring member fitted on said upper end portion within said annular recess therein, said spring member having an outside diameter greater than an inside diameter of said internal ledge but less than an inside diameter of the remainder of said passageway above said ledge such that said spring member extends outwardly from said recess so as to overlie said internal ledge and thereby interfere therewith to limit said upward movement of said upper hold-down plate in the direction away from said lower adapter plate along said guide thimble extension member but not limit downward movement of said upper hold-down plate in the opposite direction toward said lower adapter plate, said spring member being resiliently yieldable so as to bias said hold-down plate in an opposite direction toward said lower adapter plate and against the bias of said hold-down spring for absorbing the energy of an impulse load applied to said hold-down plate in the direction upwardly along said guide thimble extension member so as to thereby limit transfer of said load to said guide thimble extension member. a lower upwardly-facing shoulder on said upper end portion of said guide thimble extension member; and an upper detachable member releasably applied to said upper end portion of said extension member. 2. The improved joint structure as recited in claim 1, wherein said first overlapping means is an internal ledge defined on said hold-down plate within said passageway thereof so as to surround said upper end portion of said extension member. 3. The improved joint structure as recited in claim 2, wherein said internal ledge is located in a lower portion of said passageway. 4. The improved joint structure as recited in claim 2, wherein said second overlapping means includes: 5. The improved joint structure as recited in claim 4, wherein said spring member is at least one belleville spring which deflects axially upon application of a large impulse load thereto via said internal ledge of said hold-down plate. 6. The improved joint structure as recited in claim 4, wherein said recess is defined between a lower upwardly-facing shoulder on said upper end portion of said guide thimble extension member and an upper detachable member releasably applied to said upper end portion of said extension member. 7. In a nuclear fuel assembly having at least one control rod guide thimble and a top nozzle, said guide thimble including an upper tubular extension member, said top nozzle including a lower adapter plate supported on said guide thimble with said extension member extending above said lower adapter plate, an upper hold-down plate having a passageway slidably receiving an upper end portion of said guide thimble extension member and at least one hold-down spring disposed between said plates so as to bias said upper hold-down plate for movement upwardly along said extension member in a direction away from said lower adapter plate, an improved joint structure flexibly interconnecting said hold-down plate with said upper end portion of said guide thimble upper extension member, said joint structure comprising: 8. The improved joint structure as recited in claim 7, wherein said spring member is in the form of a stack of belleville springs which deflect axially upon application of a large impulse load thereto via said internal ledge of said hold-down plate. 9. The improved joint structure as recited in claim 7, wherein said means defining said recess includes: 10. The improved joint structure as recited in claim 9, wherein said detachable member is a retainer nut threadably attached to a terminal end of said upper end portion of said extension member such that when said nut is removed from said extension member, said top nozzle spring member can be disassembled from said guide thimble extension member.
	claims	1. A method for manufacturing at least a portion of a grid or collimator with at least some non-parallel walls orientation, having at least one layer comprising a plurality of walls defining openings therein, and being adaptable for use with an electromagnetic energy emitting device that generates a sheet x-ray beam with the long dimension in the x-direction and the short dimension in the y-dimension propagating in the z-direction, the method comprising the steps of:attaching a photoresist material onto a substrate; covering the photoresist with a mask having a plurality of aperture therein; irradiating parallel sheet beam of x-rays of energy onto the first mask, such that some of the rays of energy enter at least some of the apertures in the first mask and strike portions of the photoresist as the first mask and photoresist/substrate assembly scans in the y-direction and the assembly forms a predetermined angle with respect to the z-direction at each y-location; covering the photoresist with a second mask having a plurality of aperture therein; rotating the photoresist/substrate assembly by approximately an angle θ, in an x-y plane; irradiating parallel sheet beam of x-rays of energy onto the second mask, such that some of the rays of energy enter at least some of the apertures in the second mask and strike portions of the photoresist as the second mask and photoresist/substrate assembly scans in the y-direction and the assembly forms a second set of predetermined angles with respect to the z-direction at each y-location; rotating the photoresist/substrate by approximately an angle θ/2, in an x-y plane and covering the photoresist with a third mask having a plurality of aperture therein to form corners of the focused grid or collimator; irradiating parallel sheet beam of x-rays of energy onto the third mask, such that some of the rays of energy enter at least some of the apertures in the third mask and strike portions of the photoresist as the third mask and photoresist/substrate assembly scans in the y-direction and the assembly forms a third set of predetermined angles with respect to the z-direction at each y-location; removing portions of said photoresist material to create openings in said photoresist material exposing areas of said substrate; and placing septal wall material in said openings in said photoresist material on said exposed areas of said substrate. 2. The method as claimed in claim 1, wherein said some of the rays enter at least some of the apertures in the mask at an entering angle other than 0° with respect to a front surface of the mask. 3. The method as claimed in claim 1, wherein said removing includes using a developing solution to remove said portions of said photoresist material before placing the septal wall material. 4. The method as claimed in claim 1, further comprising:removing said substrate from said material. 5. The method as claimed in claim 1, wherein said substrate removing step removes said substrate from said material by abrasion. 6. The method as claimed in claim 1, further comprising:removing remaining portions of said photoresist material from said grid after placing the wall material. 7. The method as claimed in claim 1, wherein:said photoresist material includes a positive photoresist; and wherein the method further comprises removing said portions of said photoresist material exposed to beam of ray of energy in a positive photoresist developing solution. 8. The method as claimed in claim 1, wherein:said photoresist material includes a negative photoresist; and wherein the method further comprises removing said portions of said photoresist material unexposed to beams of ray of energy in negative photoresist developing solution. 9. The method as claimed in claim 1, wherein said wall material placing step includes electroforming said material on said exposed areas of said substrate. 10. The method as claimed in claim 1, wherein said wall material placing step includes electroplating said material on said exposed areas of said substrate. 11. The method as claimed in claim 10, wherein said wall material includes at least one of the following: nickel, nickel-iron, copper, silver, gold, lead, tungsten, uranium, or any other common electroplating/electroforming or casting materials. 12. The method as claimed in claim 1, further comprising:forming a plurality of said layers by performing said steps recited in claim 1 to form each said layer; and stacking said layers to form said grid. 13. The method as claimed in claim 1, wherein said substrate base material includes a graphite substrate. 14. The method as claimed in claim 1, wherein said substrate base material includes a silicon substrate coated with a plating base. 15. The method as claimed in claim 1, further comprising:forming a plurality of said portion of a grid or collimator by performing said steps recited in claim 1 to form each said portion of a grid or collimator; and assembling said portions of a grid or collimator to form a said layer of a said grid or collimator. 16. The method as claimed in claim 1, further comprising:repeating the steps of covering of the mask, irradiation of rays of energy and removing at least a portion of the mask a number of appropriate times. 17. The method as claimed in claim 1, the angle of rotation θ of the substrate is approximately 90 degrees. 18. The method as claimed in claim 1, wherein the orientation of some of the walls is focused to a line. 19. The method as claimed in claim 1, wherein the focal distance of some parts of the wall is different than the focal distance at other walls. 20. The method as claimed in claim 1, wherein the orientation of some of the walls is focused to a different line than the orientation of other parts of the walls. 21. A method of manufacturing at least a portion of an air-core grid or focused collimator, having at least one layer comprising a plurality of walls defining openings therein, and being adaptable for use with an electromagnetic energy emitting device, the method comprising the steps of:attaching a machinable mold material onto a substrate base; ablating portions of the machinable material to create mold openings; placing a septa wall material in said openings in said machinable material forming septal walls of the grid or collimator; removing substrate base material; and removing remaining portion of said mold material from said grid or collimator. 22. The method as claimed in claim 21, wherein said machinable mold material is negative photoresist. 23. The method as claimed in claim 21, wherein the mold material is a material that can be removed. 24. The method as claimed in claim 21, wherein the substrate base material includes graphite substrate. 25. The method as claimed in claim 21, wherein the step of removing said substrate base material comprises:abrading said base material from said at least one layer. 26. The method as claimed in claim 21, wherein the step of ablating portions of the machinable material to create mold openings comprises:ablating said mold material by mechanical machining. 27. The method as claimed in claim 21, wherein the step of ablating portions of the machinable material to create mold openings comprises:ablating said mold material by laser ablation. 28. The method as claimed in claim 21, wherein the step of ablating portions of the machinable material to create mold openings comprises:ablating said mold material by reactive ion etching. 29. The method as claimed in claim 21, wherein said wall material placing step comprises:electroforming said material on said exposed areas of said base material. 30. The method as claimed in claim 21, wherein said wall material placing step comprises:electroplating said material on said exposed areas of said base material. 31. The method as claimed in claim 21, wherein said wall material includes at least one of the following: nickel-iron, copper, silver, gold, lead, tungsten, uranium, or any other common electroplating/electroforming or casting materials. 32. The method as claimed in claim 21, where said wall material includes casting. 33. The method as claimed in claim 21, further comprising:forming a plurality of said layers by performing said steps recited in claim 21 to form each said layer; and stacking said layers to form said grid. 34. The method as claimed in claim 21, further comprising:forming a plurality of said layers by performing said steps recited in claim 21 to form each said layer; and assembling said layers to form said grid. 35. The method as claimed in claim 21, further comprising the steps of:repeating said steps of ablating portions of the machinable material to create openings and placing a septa wall material in said openings in said machinable material forming septal walls of the grid or collimator prior to removal of the mold and substrate. 36. The method as claimed in claim 21, wherein the orientation of some of the walls is focused to a line. 37. The method as claimed in claim 21, wherein the focal distance of parts of the wall is different than the focal distance at other parts of the wall. 38. The method as claimed in claim 21, wherein the orientation of some of the walls is focused to a different line than the orientation of other walls.
	claims	1. A non-destructive inspection device, comprising a radiation source unit, a grating group and a radiation ray detector unit, wherein:the radiation source unit is configured to irradiate radiation rays having transmissivity to a subject toward the grating group;the grating group is composed of a plurality of gratings that transmit the radiation rays irradiated toward the grating group;each of the plurality of gratings includes a plurality of grating members arranged at a predetermined period determined for each grating;the radiation ray detector unit is configured to detect the radiation rays diffracted by the plurality of grating members;a radiation ray passage area through which the radiation rays irradiated from the radiation source unit and reaching the radiation ray detector unit pass includes at least first to third partial areas;the first to third partial areas are arranged at positions displaced from each other in a direction intersecting with an irradiation direction of the radiation rays; andwhen a part of the grating group located in a space through which each of the radiation rays to be transmitted through any one of the first to third partial areas passes is called a reference grating partial group and parts of the grating group located in spaces through which the radiation rays to be transmitted through the other ones of the first to third partial areas pass are respectively called first and second grating partial groups, the grating members of some of the gratings included in the reference grating partial group are arranged at the predetermined period in this grating, some of the gratings included in the first grating partial group includes a grating member having a first phase difference with respect to the arrangement at the predetermined period in some of these gratings, and some of the gratings included in the second grating partial group includes a grating member having a second phase difference with respect to the arrangement at the predetermined period in some of these gratings, wherein:each of the first to third partial areas includes a mutually overlapping part and a non-overlapping part;the grating member having the first phase difference and the grating member having the second phase difference are both arranged in the non-overlapping parts; andthe radiation source unit is configured to irradiate the radiation rays to the first to third partial areas at different timings; andwherein:one of the plurality of gratings is a G0 grating which constitutes a micro radiation source array,a part of the G0 grating belonging to the reference grating partial group, a part of the G0 grating belonging to the first grating partial group, and a part of the G0 grating belonging to the second grating partial group are arranged while being spaced apart or adjacent in the direction intersecting with the irradiation direction of the radiation rays, andthe first and second phase differences are set between the part of the G0 grating belonging to the reference grating partial group, the part thereof belonging to the first grating partial group, and the part thereof belonging to the second grating partial group. 2. The non-destructive inspection device according to claim 1, wherein:the radiation ray detector unit is configured to detect the radiation rays transmitted through the reference grating partial group, the radiation rays transmitted through the first grating partial group and the radiation rays transmitted through the second grating partial group. 3. The non-destructive inspection device according to claim 2, further comprising a processing unit, wherein:the processing unit is configured to calculate any one of an absorption image, a refraction image and a scattering image of the subject using detection values of the radiation rays transmitted through the reference grating partial group, detection values of the radiation rays transmitted through the first grating partial group and detection values of the radiation rays transmitted through the second grating partial group. 4. The non-destructive inspection device according to claim 1, further comprising a conveying unit, wherein:the conveying unit is configured to move the subject relative to the grating group in the direction interesting with the irradiation direction of the radiation rays. 5. The non-destructive inspection device according to claim 1, wherein:the grating group is composed of two gratings. 6. The non-destructive inspection device according to claim 1, wherein:the grating group is composed of three gratings. 7. The non-destructive inspection device according to claim 1, wherein:the radiation source unit includes first to third ray sources;the first ray source unit is configured to irradiate the radiation rays transmitted through the first partial area;the second ray source unit is configured to irradiate the radiation rays transmitted through the second partial area; andthe third ray source unit is configured to irradiate the radiation rays transmitted through the third partial area. 8. The non-destructive inspection device according to claim 1, wherein:the first and second phase differences are set at values capable of performing phase imaging using a detection result of the radiation rays transmitted through the reference grating partial group, a detection result of the radiation rays transmitted through the first grating partial group and a detection result of the radiation rays transmitted through the second grating partial group. 9. The non-destructive inspection device according to claim 1, wherein:the radiation rays are X-rays or neutron rays. 10. The non-destructive inspection device according to claim 1, further comprising a driving unit, wherein:the driving unit is configured to move the radiation source unit, the grating group and the radiation ray detector unit as a whole relative to the subject in the direction intersecting with the irradiation direction of the radiation rays. 11. The non-destructive inspection device according to claim 1, wherein:the subject is a living body. 12. A medical image diagnosis device, comprising the non-destructive inspection device according to claim 11 and an image presentation unit, wherein:the image presentation unit is configured to present an absorption image, a refraction image or a scattering image obtained from information of the radiation rays detected by the radiation ray detector unit as an image for diagnosis. 13. A non-destructive inspection method using the non-destructive inspection device according to claim 1, comprising:a step of moving the subject relative to the grating group in the direction intersecting with the irradiation direction of the radiation rays;a step of detecting the radiation rays transmitted through the subject when the subject passes through the reference grating partial group;a step of detecting the radiation rays transmitted through the subject when the subject passes through the first grating partial group; anda step of detecting the radiation rays transmitted through the subject when the subject passes through the second grating partial group. 14. The non-destructive inspection device according to claim 1, wherein:the entire non-destructive inspection device rotatable about a rotation axis that passes through the subject so that the subject moves relative to the non-destructive inspection device.
	summary
	summary
	summary
041535065	claims	1. A method of starting operation of a nuclear reactor in which fresh fuel rods are installed of the type having a plurality of cylindrical oxide pellets and a moisture getter enclosed in an elongated tubular cladding of a zirconium alloy comprising: a first step of increasing fuel power produced by the fuel rods to a fuel power amount below an amount which causes an interaction between the pellets and the claddings in the fuel rods, a second step of maintaining the fuel power amount below the interaction amount for a predetermined period, and a third step of increasing the fuel power amount to a desired maximum power level of the nuclear reactor after the predetermined period. 2. The method according to claim 1, wherein the fuel power amount in the first step is greater than an amount which is large enough to heat the surface of the pellets to remove residual H.sub.2 O from the fuel rods. 3. The method according to claim 2, wherein the fuel power amount in the second step is kept constant below the amount which causes an interaction between the pellets and the claddings in the fuel rods for the predetermined period. 4. The method according to claim 3, wherein the predetermined period is a sufficient period to remove the residual H.sub.2 O from the fuel rods. 5. The method according to claim 4, wherein the fuel power amount P(Kw/ft) in the first step is smaller than an amount P.sub.1 (Kw/ft) determined from an equation; EQU P.sub.1 = 366 .times. (G/D) - 1.38, 6. The method according to claim 5, wherein the fuel power amount P(Kw/ft) in the first step is larger than an amount P.sub.2 (Kw/ft) determined from an equation; EQU P.sub.2 = 9.54 - 123 .times. (G/D) - 0.016 T, 7. The method according to claim 1, wherein the fuel power amount P(Kw/ft) in the first step is determined by the inequality EQU P.sub.1 > P .gtoreq. P.sub.2 8. The method according to claim 7, wherein the fuel power amount P is maintained at a constant level for the predetermined period in the second step. 9. The method according to claim 8, wherein the predetermined period in the second step is a sufficient period of time to remove the residual H.sub.2 O from the fuel rods. 10. The method according to claim 1, wherein the first and second steps are effected so as to sufficiently absorb moisture into the moisture getter to minimize fuel rod damage due to hydride localization.
041815726	claims	1. A closure head for a nuclear reactor comprising: a stationery outer ring disposed on a reactor vessel; a first rotatable plug disposed within said stationery outer ring defining a first annulus therebetween for enclosing internals of said reactor vessel and for positioning refueling equipment; a first bearing assembly mounted in said stationery outer ring and in contact with said first rotatable plug for supporting said first rotatable plug from said stationary outer ring; first seal means disposed in said first annulus for preventing passage of gases through said first annulus; first biasing means mounted on said stationery outer ring and near said first seal means for selectively contacting said first seal means and urging said first seal means into contact with said first rotatable plug thereby sealing said first annulus; and first fluid means connected to said first annulus near said first bearing assembly for introducing a fluid into said first annulus and into contact with said first seal means causing said first seal means to compress said first biasing means and allowing said fluid to pass over said first seal means while forming a fluid layer between said first seal means and said first rotatable plug thereby sealing said first annulus. second seal means disposed in said first annulus such that said first bearing assembly is disposed between said first seal means and said second seal means for preventing passage of gases through said first annulus; and second biasing means mounted on said stationery outer ring and near said second seal means for selectively contacting said second seal means and urging said second seal means into contact with said first rotatable plug thereby sealing said first annulus, said first fluid means also causing said fluid to contact said second seal means and causing said second seal means to compress said second biasing means and allowing said fluid to pass over said second seal means while forming a fluid layer between said second seal means and said first rotatable plug thereby sealing said first annulus. a first housing mounted on said stationery outer ring; a first spring mounted in said first housing and extending toward said first tubular seal member; and a first contact member mounted on said first spring near said first tubular seal member, said first spring causing said first contact member to contact said first tubular member thus forcing said first tubular member against said first rotatable plug. a second housing mounted on said stationery outer ring; a second spring mounted in said second housing and extending toward said first tubular seal member; and a second contact member mounted on said second spring near said second tubular seal member, said second spring causing said second contact member to contact said second tubular member thus forcing said second tubular member against said first rotatable plug. a fluid source; an inlet conduit connected between said first annulus near said first bearing assembly and said fluid source for conducting said fluid from said fluid source to said first annulus; a first return conduit connected at one end to said first annulus so that said first seal means is between said first bearing assembly and said first return conduit for conducting said fluid to said fluid source; and a second return conduit connected at one end to said first annulus so that said second seal means is between said first bearing assembly and said second return conduit for conducting said fluid to said fluid source. a pump connected in said inlet conduit for forcing said fluid through said inlet conduit; and a recirculating system connected around said pump for maintaining a constant volume flow through said pump. an outer race mounted in said first rotatable plug; a bearing ball disposed in said outer race; an inner race mounted in said stationery outer ring for supporting said bearing ball, said inner race having a clearance on its inner diameter between said inner race and said bearing ball for accommodating differential thermal expansion of the components of said closure head. a gas inlet line connected to said first annulus for conducting a purge gas to said first annulus; and a gas outlet line connected to said first annulus for conducting said purge gas from said first annulus thus purging said first annulus and removing contaminants therefrom. a second rotatable plug disposed within said first rotatable plug defining a second annulus therebetween for enclosing said internals of said reactor vessel and for positioning said refueling equipment; a second bearing assembly mounted in said first rotatable plug and in contact with said second rotatable plug for supporting said second rotatable plug from said first rotatable plug; third seal means disposed in said second annulus for preventing passage of gases through said second annulus; third biasing means mounted in said first rotatable plug and near said third seal means for selectively contacting said third seal means and urging said third seal means into contact with said second rotatable plug thereby sealing said second annulus; and third fluid means connected to said second annulus near said second bearing assembly for introducing a second fluid into said second annulus and into contact with said third seal means causing said third seal means to compress said third biasing means and allowing said second fluid to pass over said third seal means while forming a fluid layer between said third seal means and said second rotatable plug thereby sealing said second annulus. 2. The closure head according to claim 1 wherein said closure head further comprises: 3. The closure head according to claim 2 wherein said first annulus has a portion formed into a dip seal between said first seal means and said second seal means for further preventing passage of said gases therethrough. 4. The closure head according to claim 3 wherein said first seal means comprises a first tubular seal member disposed in said first annulus and extending around the circumference of said first rotatable plug. 5. The closure head according to claim 4 wherein said second seal means comprises a second tubular seal member disposed in said first annulus and extending around the circumference of said first rotatable plug. 6. The closure head according to claim 5 wherein said first biasing means comprises: 7. The closure head according to claim 6 wherein said second biasing means comprises: 8. The closure head according to claim 7 wherein said first fluid means comprises: 9. The closure head according to claim 8 wherein said fluid source comprises: 10. The closure head according to claim 9 wherein said fluid is a lubricating liquid for lubricating said first bearing assembly while sealing said first annulus. 11. The closure head according to claim 10 wherein said lubricating liquid is silicone. 12. The closure head according to claim 11 wherein said first bearing assembly comprises: 13. The closure head according to claim 12 wherein said closure head further comprises: 14. The closure head according to claim 1 wherein said closure head further comprises:
	abstract	One embodiment relates to an objective lens utilizing magnetic and electrostatic fields which is configured to focus a primary electron beam onto a surface of a target substrate. The objective lens includes a magnetic pole piece and an electrostatic deflector configured within the pole piece. An electrostatic lens field is determined by the pole piece and the electrostatic deflector, and the electrostatic lens field is configured by adjusting offset voltages applied to plates of the electrostatic deflector. Other embodiments, aspects and features are also disclosed.
	summary
	description	Examples of the present invention will now be described with reference to the accompanying drawing which is a schematic illustration of an ion source for positive ions with an extraction arrangement incorporating an example of the present invention. Referring to the FIGURE, an ion source comprises an arc chamber 10 which may be configured as a Bernas source, or any other known ion source. A feed gas, here shown as BF3 is supplied to the arc chamber along a pipe 11 and the arc chamber operates to create a plasma within the arc chamber in which are formed the ions B+and BF2+, for example. These positive ions are then extracted from the arc chamber via an exit aperture 12 to form a beam. In the described example, the source is providing a beam of boron ions (or BF2 ions) which may be useful for implanting a silicon substrate with boron. However, other ions may be produced where required, such as As+, P+or Ar+, for example. The ions are extracted from the arc chamber 10 by the electric fields produced by electrodes 13 and 14. To extract positive ions from the source, the arc chamber 10 and in particular the front face 15 containing the exit aperture 12 is held at a positive potential relative to the electrodes 13 and 14. In practice, the electrode 14 may form the entrance aperture to a mass analysing magnet and will usually be at ground potential. The mass analysing magnet and a subsequent mass selection slit are used to select from the ions drawn from the arc chamber 10 ions of the precise mass required for implanting. For example, the mass analyser and mass selection slit may select only B+ions for onward transmission to the semiconductor substrate target. Neither the mass analyser magnet nor the subsequent elements of the beam path to the substrate target are illustrated in the drawing. These components may be typical of those customarily used in this art. In order to ensure that ions entering the mass analyser magnet, passing through the electrode 14, have a well defined energy, the potential of the front face 15 of the arc chamber 10 is controlled by a power supply 16. In the illustrated example, power supply 16 applies a potential of about 2 kV or less to the front face, so that the energy of the beam in the mass analyser will be correspondingly 2 keV or less depending on the potential applied. The electrode 13 constitutes an electron suppression electrode and is set by a power supply 17 at a negative potential relative to the electrode 14 so as to prevent electrons in the beam downstream of the electrode 14, in the direction of the arrow 18 from being drawn out of the beam by the positive potential on the arc chamber 10. In this way, space charge neutralisation within the analyser magnet, downstream of the electrode 14, is largely maintained. In the described example, the potential on the suppression electrode 13 is about xe2x88x92200 volts, but suppression potentials of several kilovolts below the ground potential of the analyser magnet and electrode 14 may be used. As can be seen in the drawing, a substantial electric field exists between the exit aperture 12 of the arc chamber and the suppression electrode 13, and also, though to a lesser extent, between the suppression electrode 13 and the ground electrode 14 at the entrance to the mass analyser. In these regions, any electrons in the beam have very short residence times due to their small mass and high mobility. As a result, space charge neutralisation by electrons in the beam in these regions is ineffective. In the described example, a source of argon gas is supplied along a pipe 20 to expand in a chamber 21. The sudden expansion of the argon gas in the chamber 21, causes clusters of argon atoms to condense together, producing clusters each of at least 100 atoms and in appropriate conditions, up to 1000 atoms or more. Within the chamber 21, a heated cathode, 22 emits electrons, which arc accelerated through a grid electrode 23. The cathode 22 is biased relative to the grid 23 by a power source 24 to produce electrons of low energy (below about 50 eV). The resulting xe2x80x9csprayxe2x80x9d of low energy electrons passing through the grid 23 ionises argon clusters within the chamber 21, forming negatively charged cluster ions. The cluster ions in the chamber 21 diffuse from the chamber through an aperture 25 immediately adjacent the electron suppression electrode 13. The resulting flood of negatively charged cluster ions emerging from the aperture 25 assists in neutralising the space charge of the portion of the ion beam between the exit aperture 12 of the arc chamber 10 and the suppression electrode 13. As explained previously, for total space charge neutralisation, the density in a particular region of the ion beam of positive ions should equal the density of negative cluster ions (Nb=Nc). Further, Nb=Jb/evb=Nc=Jc/evc, where Jb is the current density resulting from the positive beam ions, vb is the velocity of those ions in the beam, Jc is the current density in the beam of negative cluster ions, and vc is their velocity. If at a particular location in the beam, the energy of the required positive ions is equal to the energy of the negative cluster ions, mb vb2=mc vc2, where mb is the mass of the positive ions and mc is the mass of the cluster ions. From the above, Jb/Jc=vb/vc=(mc/mb). Cluster ions comprising between 200 and 300 argon atoms are typically formed in the chamber 21. However, taking a minimum of 100 atoms in a cluster ion, mcxe2x89xa74000 a.u. If the positive ion in the ion beam is B+(mass≈10.8), mc/mb≈400 and Jb/Jc≈20. Thus, for full space charge neutralisation in the region of the beam where both the positive ions and the negative cluster ions have the same energy, the current of cluster ions in the beam, accelerated by the electric field towards the exit aperture 12 of the arc chamber 10, must be about one-twentieth of the beam current of boron ions from the arc chamber. For a typical boron beam current of 5 mA, this implies a cluster ion current of 0.25 mA. In the Figure, a power supply 26 is illustrated connected to apply a negative bias to the cluster ion source relative to the electron suppression electrode 13. In fact, the cluster ion source may be held at the same potential as the suppression electrode 13, relying on any residual positive charge in the ion beam to draw cluster ions from the aperture 25 and into the beam. However, a small negative bias may additionally be applied to the cluster ion source to control the flow of cluster ions. In the illustrated example, the cluster ion source is shown delivering cluster ions on the upstream side of the suppression electrode. Since the potential difference between the arc chamber 10 and the suppression electrode 13 is likely to be greater than that between the suppression electrode 13 and the grounded electrode 14, the problem of space charge suppression in this region is most severe, especially if it is desired to extract relatively high currents at low energy from the arc chamber 10. However, cluster ions may also be delivered on the other side of the suppression electrode 13 to neutralise space charge of the ion beam in the region between the suppression electrode 13 and the grounded electrode 14. The example of the invention described above refers to a positive ion beam comprising boron ions. However, the invention is applicable equally to other desired positive ion beams. The invention may also be applied to beams of negative ions, in which case positive cluster ions are introduced. Positive cluster ions may be formed in the chamber 21 by spraying the condensed clusters of atoms with electrons of higher energy. Further, the above examples describe using argon cluster ions. Other gases may be used which can be made to produce large clusters of atoms. For ion implantation purposes, the cluster ions should be of a species which can be tolerated in the implantation process. Further, for minimum mobility of the cluster ion in the electric field regions of the ion beam, relatively heavy atoms are preferred such as xenon. Also, the above described example refers to neutralising the ion beam at the point of extraction from the arc chamber of the ion source. Examples of the invention may be used also at other regions of a beam where an external electric field renders the lifetime of any electrons in the beam extremely short so that space charge neutralisation becomes a problem. For example, negative cluster ion neutralisation may be employed in a region where the ion beam is accelerated, and more particularly decelerated, by means of an electric field prior to impact on a target. Also cluster ions may be used to provide beam space charge neutralisation in a region where a beam is scanned transversely. In this case, the cluster ion neutralisation process described may be useful even if the beam scanning is conducted by magnetic fields, rather than electric fields. In such regions, self neutralisation of the ion beam, by the creation of electrons through collisions with residual gas atoms, may be insufficient to maintain adequate control of the beam potential. The beam may be scanned too rapidly to allow sufficient numbers of electrons to accumulate in the beam to provide adequate neutralisation. Flooding the scanning region with massive negative cluster ions should substantially improve beam neutralisation. Ions of opposite polarity may also be used for neutralising an ion beam at other locations along the beam between the ion beam source and the ion beam process target. For example, such opposite polarity ions may be injected into the ion beam containing volume of a magnet used for mass analysis (or energy analysis) of the process ion beam. Improved beam neutralisation and control may then be achieved in the magnet, especially at low beam energies and high beam currents. Opposite polarity ions may also be used to neutralise an ion beam in so called drift regions of no electric or magnetic field. Examples of drift regions in an ion implanter are between the ion source extraction optics and the entrance to the mass analysis magnet, between the mass analysis magnet and the mass resolving system, and between a post mass selection acceleration (or deceleration) stage and a substrate neutralisation system. The invention is not restricted to the use of cluster ions for neutralising the beam. Some improvement in beam control may be achieved with ions of the second polarity (negative ions for a positive ion beam). Even He has a mass 4 which is about 104 times the rest mass of an electron (xcx9c5.5xc3x9710xe2x88x924 a.u.), so that the current density of Hexe2x88x92for the same neutralising effect is only one hundredth that for electrons. Generally, the second polarity ions should be of a species which will not have substantial deleterious effects in the process. More massive ions and cluster ions are preferred, especially for neutralising in regions of applied electric field.
	summary
044501340	claims	1. An improved method for transferring nuclear elements between a fluid storage pool and a fuel transfer cask comprising the steps of: (a) positioning at a first terminal location a transport having an aperture formed in a frame thereof and a cask tank vertically supported in said aperture on said transport and extending through said aperture; (b) introducing and supporting a nuclear fuel element cask into said tank at said first terminal location; (c) establishing a fluid sealed barrier between inner and outer surfaces of said cask; (d) advancing said transport in a horizontal direction to a second terminal location adjacent an overhead port of a nuclear fuel storage pool; (e) advancing said tank in a vertical direction toward said port at said second terminal location; (f) supporting said tank in engagement with said port; and, (g) establishing a fluid seal between said tank and said port. (a) Positioning at a first terminal location a transport having an aperture formed in a frame thereof and a cask tank vertically supported on said transport and extending through said aperture; (b) introducing and supporting a nuclear fuel element cask in said tank at said first terminal location and establishing a fluid sealed barrier between inner and outer surfaces of said cask; (c) advancing said transport in a horizontal direction to a second terminal location adjacent an overhead port of a nuclear fuel storage pool; (d) aligning said tank with respect to said port; (e) coupling said vertically orientated tank to said port and establishing a fluid sealed channel between said port and an interior of said cask; (f) flooding said sealed channel; (g) providing access between said fuel storage pool and the cask through said port; and, (h) transferring fuel elements between the said cask and said pool. (a) positioning a wheeled transport means which travels on elevated tracks in a corridor between first and second terminal locations of a nuclear facility at a first terminal location, said transport means including a frame defining an aperture formed therein and a cask tank positioned vertically in and extending through said aperture and supported on said transport, said cask tank extending below said transport means; (b) lowering a nuclear fuel element cask into said tank at said first terminal location and establishing a fluid sealed barrier between inner and outer surfaces of said cask; (c) advancing said transport means, said vertically supported tank and said cask in a horizontal direction to a said second location adjacent an overhead port of said nuclear fuel storage pool; (d) unweighting said tank from said transport by vertically advancing said tank into engagement with said port and supporting said tank from beneath by a rigid structure; (e) establishing a fluid sealed channel between said port and an interior of said cask; (f) flooding the sealed channel; (g) actuating a port closure to an open position for establishing clear access through said port between said pool and said cask; and (h) transferring fuel elements between said cask and said pool. (a) a transport means adapted for movement in a horizontal direction, said transport means having a frame and an aperture formed in said frame; (b) a tank means vertically supported on said transport means and extending through said aperture; (c) a nuclear fuel element cask having inner and outer surfaces supported in said tank means; (d) means establishing a fluid sealed barrier between inner and outer surface of said cask; (e) means for advancing said tank in a vertical direction toward an overhead port at a terminal location; (f) means for supporting said tank in engagement with said port; and, (g) means for establishing a fluid seal between said tank and said port. (a) a transport means adapted for movement in a horizontal direction, said transport means having an aperture formed in a frame thereof; (b) a tank means vertically supported on said transport and extending through said aperture; (c) a nuclear fuel element cask supported in said tank means; (d) means for establishing a fluid sealed barrier between an overhead port and said tank means at a terminal location; (e) means for aligning said tank with respect to said overhead port; and, (f) means for coupling said vertically orientated tank to said port and for establishing a fluid sealed channel between said port and an interior of said cask. 2. An improved method for transferring nuclear fuel elements between a fluid filled storage pool and a fuel transfer cask comprising the steps of: 3. The method of claim 2 including the step of guiding the advancement of said tank into engagement with said port. 4. The method of claim 1 wherein said tank is vertically advanced by elevating and unweighting said tank from said transport and supporting said tank from a rigid structure. 5. The method of claim 4 wherein said tank is elevated and unweighted from said transport by applying a lifting force to a lower surface of said tank and supporting said tank at said lower surface. 6. The method of claim 1 wherein said tank is vertically advanced by establishing a lifting force between said tank and said transport means. 7. The method of claim 6 wherein said lifting force is established by a lifting means positioned on said transport means for transport therewith. 8. The method of claim 2 wherein said coupling of said tank to said port is provided by extending a bellows coupling means between said port and said tank. 9. The method of claim 2 including seismically restraining said transport at said second location. 10. An improved method for transferring nuclear fuel elements between a fuel storage pool of a nuclear facility and a nuclear fuel transfer cask comprising the steps of: 11. An improved apparatus for transferring nuclear elements between a fluid storage pool and a fuel transfer cask comprising: 12. An improved apparatus for transferring nuclear fuel elements between a fluid filled storage pool and a fuel transfer cask comprising: 13. The apparatus of claim 12 including means for guiding the advancement of said tank into engagement with said port. 14. The apparatus of claim 11 including lifting means vertically advancing said tank, unweighting said tank from said transport, and for supporting said tank on a rigid structure. 15. The apparatus of claim 14 wherein said lifting means is positioned for applying a lifting force to a lower surface of said tank. 16. The apparatus of claim 11 wherein said means for vertically advancing said tank establishes a lifting force between said tank and said transport means. 17. The apparatus of claim 16 wherein said lifting means is positioned on said transport means for transport therewith. 18. The apparatus of claim 12 wherein said coupling means includes a bellows extending between said port and said tank. 19. The method of claim 12 including means for seismically restraining said transport means at a terminal location. 20. The apparatus of claim 15 wherein said means for support said tank on a rigid structure supports said tank at said lower surface.
	summary
	claims	1. An energy reclamation system comprising:a plurality of storage cavities having substantially vertical axes and arranged in a spaced-apart side-by-side manner;at least one hermetically sealed canister containing spent nuclear fuel emanating heat positioned within each of the storage cavities;an air-intake passageway extending from an ambient environment to a bottom portion of each of the storage cavities;an air-outlet manifold fluidly coupling a top portion of each of the storage cavities to an air-outlet passageway, the air outlet manifold converging heated air exiting the top portions of the storage cavities and directing said converged heated air into the air-outlet passageway, the air-outlet manifold comprising a first network of pipes that directly fluidly couples the top portion of each storage cavity to either: (1) the top portion of at least two other ones of the storage cavities; or (2) one other one of the storage cavities and the air-outlet passageway, so that the top portion of each of the storage cavities is fluidly coupled to at least one other one of the storage cavities and to the air-outlet passageway; andan energy reclamation unit located within the air-outlet passageway. 2. The system of claim 1 further comprising an air-intake manifold fluidly coupling the bottom portions of the storage cavities to an air-intake cavity. 3. The system of claim 2 wherein the air-intake manifold comprises a second network of pipes forming hermetically sealed passageways between the bottom portions of the storage cavities and the air-intake cavity. 4. The system of claim 3 wherein each of the storage cavities is formed by a storage shell and the air-intake cavity is formed by an air-intake shell. 5. The system of claim 4 wherein the first network of pipes forms hermetically sealed passageways between the top portions of the storage cavities and the air-outlet passageway. 6. The system of claim 5 wherein each of the storage shells comprises at least one outlet opening to which the first network of pipes is fluidly coupled and at least one inlet opening to which the second network of pipes is fluidly coupled, and wherein for each of the storage cavities, a bottom of the canister is located above a top of the inlet opening and a top of the canister is located below a bottom of the outlet opening. 7. The system of claim 5 further comprising:a ground having a grade;wherein the storage shells are positioned so that at least a major portion of a height of each storage shell is located below the grade and a top edge of each storage shell is at or above the grade, the first and second network of pipes being located below the grade;the air-intake cavity forming a passageway between an opening located above the grade and the second network of pipes; andthe air-outlet passageway extending from the first network of pipes to an opening located above the grade. 8. The system of claim 7 wherein the storage shells, the air-intake shell, and the first and second networks of pipes are hermetically sealed against the ingress of below grade liquids. 9. The system of claim 7 wherein the top edge of each storage shell defines an opening through which the canisters can be inserted into the storage cavities, and the system further comprising a lid detachably coupled to the top edge of each of the storage shells to enclose the storage cavities. 10. The system of claim 1 wherein each of the storage cavities is formed by a storage shell, and wherein for each storage cavity, a gap exists between the storage shell and the canister, the horizontal cross-section of the storage cavity accommodating no more than one of the canisters. 11. The system of claim 10 further comprising one or more layers of insulating material circumferentially surrounding the vertical axis of each storage cavity and affixed to the storage shell. 12. The system of claim 1 wherein the first network of pipes forms hermetically sealed horizontal passageways between the top portions of the storage cavities and the air-outlet passageway, the air outlet passageway being substantially vertical. 13. The system of claim 1 wherein the energy reclamation unit is a heat exchanger. 14. An energy reclamation system comprising:a plurality of storage cavities having substantially vertical axes and arranged in a spaced-apart side-by-side manner;at least one hermetically sealed canister containing spent nuclear fuel emanating heat positioned within each of the storage cavities;an air-intake passageway extending from an ambient environment to a bottom portion of each of the storage cavities;an air-outlet manifold fluidly coupling a top portion of each of the storage cavities to an air-outlet passageway, the air outlet manifold converging heated air exiting the top portions of the storage cavities and directing said converged heated air into the air-outlet passageway;an energy reclamation unit located within the air-outlet passageway; andwherein each of the storage cavities is formed by a storage shell, and further comprising a lid detachably coupled to a top edge of each of the storage shells to enclose the storage cavities, wherein each of the storage shells comprises at least one opening to which the air-outlet manifold is fluidly coupled, and wherein the at least one opening is formed directly into the storage shell at a location below the lid. 15. An energy reclamation system comprising:a plurality of storage cavities having substantially vertical axes and arranged in a spaced-apart side-by-side manner;at least one hermetically sealed canister containing spent nuclear fuel emanating heat positioned within each of the storage cavities;an air-intake passageway extending from an ambient environment to a bottom portion of each of the storage cavities;an air-outlet manifold fluidly coupling a top portion of each of the storage cavities to an air-outlet passageway, the air outlet manifold converging heated air exiting the top portions of the storage cavities and directing said converged heated air into the air-outlet passageway, the air-outlet manifold comprising a network of pipes forming hermetically sealed passageways that extend directly between the top portions of adjacent ones of the storage cavities and directly between at least one of the storage cavities and the air-outlet passageway; andan energy reclamation unit located within the air-outlet passageway. 16. The system of claim 15 wherein the top portions of each of the storage cavities is directly fluidly coupled to either: (1) the top portion of at least two other ones of the storage cavities; or (2) one other one of the storage cavities and the air-outlet passageway. 17. The system of claim 15 wherein each of the storage cavities is formed by a storage shell, and wherein the network of pipes comprises at least one pipe having a first end coupled directly to One of the storage shells and as second end coupled directly to the air-outlet passageway.
	claims	1. A method for imaging an object, the method comprising:acquiring a first projection image of the object using a source and a detector, wherein the first projection image comprises a primary image of the object and a scatter image of the object;positioning a scatter rejecting aperture plate between the object and the detector, wherein the aperture plate comprises a high-density material and defines a plurality of sub-centimeter sized apertures, wherein the apertures are positioned on a hexagonal grid;acquiring a second projection image of the object with the scatter rejecting aperture plate disposed between the object and the detector, wherein the second projection image comprises the primary image of the object;generating the scatter image of the object based on the first projection image and the second projection image; andstoring the scatter image of the object for subsequent imaging, wherein subsequent imaging comprises reconstructing a three-dimensional image of the object based on a scatter free projection image by subtracting the scatter image of the object from the projection images,wherein a respective scatter image is generated and stored for each of a plurality of projection angles, said plurality of projection angles being realized by relatively rotating the object and the radiation source in a common plane of rotation, andwherein the hexagonal grid comprises grid lines and one of the grid lines of the hexagonal grid is inclined against a surface normal of the common plane of rotation by an inclination angle being in the range of 0 to 15 degrees, wherein the inclination angle is greater than 0 degrees. 2. The method of claim 1, wherein the reconstructing of the three-dimensional image of the object based on a scatter free projection image comprises subtracting the scatter image of the object from the projection images in a single subtraction process step. 3. The method of claim 1, wherein generating the scatter image further comprises generating a scatter grid image by subtracting the second projection image from the first projection image. 4. The method of claim 3, wherein generating the scatter image further comprises detecting a plurality of aperture points for the scatter grid image and interpolating the scatter grid image based on the aperture points. 5. The method of claim 1, wherein subsequent imaging comprises acquiring a plurality of projection images of the object from a plurality of projection angles, wherein the plurality of projection angles are realized by relatively rotating the object and the radiation source in a common plane of rotation. 6. The method of claim 5, wherein subsequent imaging comprises generating a plurality of scatter free projection images based on the projection images and respective scatter images. 7. The method of claim 5, wherein reconstructing comprises normalizing and correcting at least one bad pixel in a plurality of scatter free projection images. 8. The method of claim 1, further comprising maintaining a plurality of substantially similar imaging parameters. 9. The method of claim 8, wherein the imaging parameters are selected from the group consisting of a type of object being imaged, a shape and an orientation of the object being imaged, projection angles from which the scatter images and subsequent projection images are acquired, an x-ray technique being employed, a geometry and one or more settings of the source and the detector, and combinations thereof. 10. The method of claim 1, wherein the apertures comprises a diameter and a next-neighbor distance between edges of the apertures, wherein the ratio between the next-neighbor distance and the diameter is in the range of 2 and 3. 11. The method of claim 1, wherein the diameter of the apertures are in the range of 1.5 to about 2.5 millimeters. 12. The method of claim 1, wherein the distance between next-neighbor apertures are in the range of 4 to 6 millimeters. 13. The method of claim 1 further acquiring a plurality of projection images of the object at a plurality of projection angles generating a plurality of scatter free projection images by correcting the plurality of projection images based on the respective ones of the plurality of stored scatter images by subtracting the scatter images from the respective projection images in a single process step, wherein the scatter images are generated and stored for each of the projection angles and reconstructing a three-dimensional image of the object based on the scatter free projection images. 14. The method of claim 13, wherein the apertures have a diameter and a next-neighbor distance between edges of the apertures, and wherein the ratio between the next-neighbor distance and the diameter is in the range of 2 and 3. 15. The method of claim 13, wherein the diameter of the apertures are in the range of 1.5 to about 2.5 millimeters. 16. The method of claim 13, wherein the distance between next-neighbor apertures are in the range of 4 to 6 millimeters. 17. The method of claim 1, further comprising determining the inclination angle based on coincidence of a feature on the object with a first sub-centimeter sized aperture of the plurality of sub-centimeter sized apertures. 18. A volumetric CT system for imaging an object, the system comprising:a source and a detector configured to move with respect to the object, wherein the detector is further configured to acquire a plurality of projection images of the object from a plurality of projection angles; anda processor configured to generate a plurality of scatter free projection images in a single process step by correcting the projection images based on respective stored scatter images, subtracting the scatter images from the respective projection images, and to reconstruct a three-dimensional image of the object based on the scatter free projection images, wherein the scatter images are generated and stored for each of the projection angles by employing a scatter rejecting aperture plate positioned between the object and the detector, and wherein the aperture plate comprises a high-density material and defines a plurality of sub-centimeter sized apertures, wherein the apertures are positioned on an hexagonal grid;wherein one of the grid lines of the hexagonal grid is inclined against a surface normal of a common plane of rotation of the object and the radiation source by an inclination angle, said inclination angle being in the range of 0 to 15 degrees, wherein the inclination angle is greater than 0 degrees. 19. The system of claim 18, wherein for each of the projection angles, the detector is further configured to acquire a first projection image of the object and a second projection image of the object with the scatter rejection plate positioned between the object and the detector, and wherein the processor is further configured to generate the scatter image of the object at the respective one of the projection angles based on the first projection image and the second projection image. 20. The system of claim 19, wherein said plurality of projection angles are realized by relatively rotating the object and the radiation source in a common plane of rotation. 21. The system of claim 19, the apertures having a diameter and a next-neighbor distance, wherein the ratio between the next-neighbor distance and the diameter is in the range of 2 and 3. 22. The system of claim 19, wherein the diameter of the apertures are in the range of 1.5 to about 2.5 millimeters. 23. The system of claim 19, wherein the distance between the next-neighbor apertures is in the range of 4 to about 6 millimeters.
044850670	abstract	A manipulator for transferring fuel assemblies between inclined fuel chutes for a liquid metal nuclear reactor.. Hoisting means are mounted on a mount supported by beams rotatably attached by pins to the mount and to the floor. Rotation of the beams can be impelled by a one dimensional movement causing the manipulator to accomplish a complicated, two dimensional transfer.
060020636	description	DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The first stage of the process entails the identification of a suitable injection site and target stratum, identified in FIG. 1 as reference 2, and to determine the extent of the site. The preferred site and target stratum will have the following characteristics: a) The site will be free of significant quantities of hydrocarbons and other valuable minerals that could become the target for exploitation in the foreseeable future. PA0 b) The target stratum will have a minimum thickness of 4 meters and be at least 0.5.times.2.0 km in extent, or be connected hydraulically to permeable strata that have these dimensions. PA0 c) The minimum transmissivity of the target stratum will be 0.5 Darcy-meters (average permeability in Darcy units multiplied by the stratum thickness in meters). PA0 d) The direction of groundwater flow in the region around the stratum will be generally horizontal, i.e., deviating from the horizontal by no more than about 2.5 degrees. PA0 e) The target stratum will comprise granular, poorly-cemented or uncemented sandstone or highly fractured porous rock. The rock will have no significant large-scale tensile fracture strength (tensile resistance to hydraulic fracturing) and a compressibility of at least 1.times.10.sup.-6 kPa..sup.-1 PA0 f) The rock in the target stratum will not react chemically with the solid or liquid phases of the slurry to release any free gases or new noxious compounds, apart from the ordinary slow dissolution of minerals which takes place in aqueous systems. PA0 g) The stratum will have a minimum porosity of about 15% in the portions that have a permeability above 100 mD (milliDarcy). PA0 h) The stratum will not be intersected by any faults or other geological features that could give direct or easy access from the stratum to surface groundwater. PA0 i) The target stratum will be overlain by at least 1-2 meters, and preferably 10 meters of low permeability overburden strata with a maximum permeability of 10 mD, for example a ductile shale or clayey siltstone. The overburden will preferably consist of alternating permeable and impermeable stratum (less than about 10 milliDarcies). This capping stratum is typically a thick, ductile non-faulting shale to best provide hydraulic isolation and a stress barrier to upward fracture propagation. The overlying permeable zones absorb wastes if hydraulic isolation of the target is breached and also act as further fracture barriers. The alternating stratigraphy further serves as a barrier to contamination of overlying groundwater zones and directs flow laterally rather than vertically. PA0 a) The well depth will be a minimum of 250 m in regions of modest surface elevational differences (20 m or less) and 500 m in hilly terrain (20-200 m). PA0 b) The well will be isolated from all shallow groundwater sources by laterally continuous overburden strata that extend a minimum of about 10 km in all directions. These barrier strata will have a combined thickness of 50 m, counting only those strata that are at least 5 m thick and shall have an aggregate transmissivity to water no greater than 0.02 Darcy-meters. PA0 c) There will be at least one "security zone" consisting of a permeable layer above the target zone to bleed off any liquid that might migrate upwards and to blunt the upward propagation of fractures. The security zone should have a transmissivity of at least 1.0 Darcy-meters and be dominated by horizontal groundwater flow, unconnected to shallow potable water sources. Preferably, at least one such zone is within 100 meters of the target stratum, and is greater than about 2 meters thick on average. This zone also serves as a barrier to contamination of overlying groundwater zones. PA0 d) The groundwater in the target stratum, security zone and all other affected strata must not be a source of potable water, and must be shown to be hydraulically isolated from regional potable drinking water (no local faults through jointed rocks). This isolation can be demonstrated isotopically or through groundwater or lithostratigraphic studies. PA0 e) The overburden may include a sedimentary sequence that includes minerals such as clays or zeolites which have the capacity to absorb wastes such as heavy metals and organics. This aspect permits moving liquids and leachates to contact large amounts of clay minerals in shale, clayey silts and in the interstices of unconsolidated sandstones, for the absorption of heavy metals, organic molecules and other contaminants. PA0 a) The total slurry volume to be injected for each well or series of wells is a function of the projected interstitial volume of the target stratum. This is determined by assessing the size of the target stratum (both area and thickness), the approximate interstitial volume, and preferably also the mechanical compressivity of the stratum. PA0 b) The target flow rate ("injection rate") for the slurry is determined by the speed at which the target stratum is capable of absorbing the slurry while maintaining a steady state well bottom pressure. Ideally, this pressure is between 115% and 135% of the overburden stress. The well bottom pressure is measured by the pressure gauge 7 positioned at the well bottom. The optimal infectivity is determined as: injection rate/(Press.sub.inj -Press.sub.fmt), where Press.sub.inj =injection pressure and Press.sub.fmt =formation pressure. PA0 c) The duration of each injection and inter-injection episode is determined by the rate at which the slurry spreads within the target stratum and the rate at which the pressure at well-bottom dissipates. The spread of slurry within the target stratum is assessed primarily by the magnitude and decay rate of ground surface uplift in the region around the well, as determined by tiltmeters or other surface uplift indicators. Typically, maximum surface uplift during an injection episode will be limited to a maximum of about 5 cm or such other value as may be set by a regulatory body. Once this amount of uplift has occurred, the episode is halted until pressure decays to an acceptable level (i.e. less than 80% of overburden stress) and the deformation rate is small. PA0 d) The localization of the injected solids within the target stratum is determined by microseismic surveillance and, in the case of shallow (.ltoreq.800 m) disposal depths, measurement of surface uplift using tiltmeters or the like. Through known analysis techniques, the localization of the region of uplift provides an indication of the lateral spread of the embedment zone, and as well provides reconstruction of the fracture behavior in terms of geometry (dip, orientation, aspect ratio) and deformation (volumetric and shear formation). Microseismic surveillance assesses by means of known techniques the horizontal and vertical positioning of the zone. PA0 Maximum slurry injection rate: 1.1-2.0 times fracture extension rate PA0 Daily slurry injection volume: 700-1500 m.sup.3 /day PA0 Waste injection volume: 50-225 m.sup.3 /day PA0 Av. slurry concentration: 5-30% sand by volume PA0 Av. slurry density: 1000-1300 kg/m.sup.3 PA0 Max. slurry density: 1375 kg/m.sup.3 PA0 Injection Pressures 1.1 to 1.5 times the fracture extension pressure PA0 injection episodes: 24 hour injection/interinjection cycle, including 4-14 hours/day injection episode PA0 injection cycle: 5 day injection cycle, 2 days shut-in or 11 day injection cycle followed by 3 day shut-in. PA0 Maximum slurry injection rate: 1.1-2.0 times fracture extension rate PA0 Daily slurry injection volume: 700-1000 m.sup.3 /day PA0 Waste injection volume: 50-100 m.sup.3 /day PA0 Av. slurry concentration: .about.15% slop by volume PA0 Av. slurry density: 1000-1200 kg/m.sup.3 PA0 Max. slurry density: 1250 kg/m.sup.3 PA0 Injection Pressures 1.1 to 1.5 times the fracture extension pressure PA0 injection episodes: 24 hour injection/interinjection cycle, including 4-14 hours/day injection episode PA0 injection cycle: 5 day injection cycle, 2 days shut-in. Additional requirements are imposed for the selection of target strata and preparation of the injection well where it is desired to dispose of wastes that will produce mildly or substantially toxic liquids (as opposed to merely salty or noxious), whether such liquids comprise the injection fluid itself or leachate resulting from interaction between the solid wastes and the carrier liquid. These additional requirements are, at a minimum: The horizontal stratification and high permeability of the target stratum ensures that long term pressures do not build up, that emplaced solids remain close to the injection well and that the carrier liquids dissipate uneventfully in the stratum. The porosity, lack of large-scale cohesion and and low fracture resistance mean that fracture initiation and extension take place repeatedly without blockages or excessive treatment pressures. The injection well is prepared by drilling into the target stratum, as described in detail below. A waste-bearing slurry is prepared, with solid wastes being suspended in the slurry in particulate form. The maximum particle size of suspended wastes is about 5 mm with no more than 15% of the particles being larger than 2.5 mm. The most desirable range of mean grain size of the slurry is between 2 .mu.m and 1000 .mu.m. The solids concentration should be a maximum of 40% by volume for fine grained materials (less than 150 .mu.m particles) or 20% for courser materials (150 .mu.m-500 .mu.m). Granular waste streams with substantial proportions greater than 1000 .mu.m will be specially analyzed to ensure that the concentration of large particles is sufficiently low as not to block perforation openings during injection. Slurry design parameters include: the amount of non-dissolved solid material in the slurry; PA1 the liquid phase viscosity (which will affect the injection rate and underground pressure bleed-off); PA1 colloidal material content (clay and polymer content); PA1 non-aqueous liquids content (e.g. oils and other immiscible liquids); PA1 content of cementitious agents (Portland (tm) cement, lime, etc.); and PA1 additives used to enhance or alter the rheology of the slurry, such as polymers, thickeners, gels or emulsifiers. PA1 finely ground gypsum, limestone or lime PA1 Ground FGD (flue gas desulphurization) sludge, which serves as permeability blocking agent PA1 ground shale, clay or other finely divided material PA1 synthetic non-biodegradable polymer agents PA1 Portland (tm) cement or other commercial cements or pozzolanic cementitious agent PA1 fly ash or finely ground combustion clinker. PA1 during pre-flush to facilitate fracture injection; PA1 during fracture screen-out conditions, when the wellbottom and head pressures unexpectedly surge. PA1 a) optimization of SFI process in terms of length of injection cycles, slurry composition, daily injection volumes and injection rates and pressures; PA1 b) maximizing hydraulic isolation and containment of the injected wastes; PA1 c) providing diagnostic information to evaluate formation stress state and flow response, well integrity, formation containment and response, in situ waste distribution, formation storage capacity and formation infectivity during the injection process; PA1 d) personnel safety during injection procedures; PA1 e) evaluation of the target stratum mechanical and flow responses to the injection process; and PA1 f) determination of the distribution of the injected material within the target stratum. PA1 slurry density measuring means 80; PA1 pump pressure measuring means 82; PA1 means 84 to measure water input into the system; PA1 means 86 to measure injection rates; PA1 a control data logger 88 linked to all of the measuring means to record and store the data in real time. A digital display 90 is provided in the data logger. The monitoring system is also linked to and receives data from the pressure gauges 7 and 10 at the well bottom and surface. Cementitious agents are added to slurries that include wastes of intermediate or high toxicity, such as PCB-contaminated soil, radioactive wastes, and heavy metals or arsenic compounds. The use of cementitious agents reduces the permeability of solid waste materials within the target zone. Thus, after the carrier liquid bleeds off, a solid waste body results that has a permeability substantially lower than that of the surrounding rock, with a consequent hydraulic isolation of the target waste body and a reduced leachate generation rate. Cementitious agents may include: The injection conditions, including the slurry composition are optimized for the particular injection conditions by determining slurry additives (including viscosifiers, surfactants and adsorbing agents), slurry viscosity, slurry waste concentrations and slurry specific gravity, as well as other SFI variables, as functions of the following considerations: Composition of waste material (e.g.. Mud/sand/slop/water ratios). An optimum mix is required to avoid excess injection pressures, formation blockage, injectivity maintenance, wellbore integrity and pump wear. The specific rations depend on many factors, many of which are identified below. The minimum water to waste rations is approximately 4:1 and the minimum sand to viscous fluid rations is approximately 0.5:1. Daily slurry injection volumes. Typically, upper slurry volume limits of 800-2000 m.sup.3 and solids volume limits of 200-300 m.sup.3 per day per injection well are used to insure that no well or formation damage occurs. Higher volumes are permissible only if geological parameters can be shown to be adequate so that the larger volumes do not lead to formation injectivity impairment, blockage, excessive pressurization or unacceptably slow pressure decay rates. Maximum sand grain size during injection. The maximum grain size is controlled by two factors: the opening diameter of the perforations in the case wellbore and the concentration of the large particles. The limit required is that the ration of the perforation opening diameter, D.sub.perf, to the diameter of the largest grains, D.sub.max, be 5 or less, and that there be no more than about 15% of the granular solid portion of the slurry in the diamter ration range of about 5-10. Unless the perforations are specifically designed accordingly, the maximum grain size should be less than about 0.5 mm. Fines/clay content during injection. Excessive amounts of fine-grained material can lead to an unacceptable formation blockage, resulting in excessively high treatment pressures during waste injection. Accordingly, the percentage of clay materials (grain size of less than about 2 microns) is limited to about 10% by volume of the total or, if the clays are not geochemically active, to an amount that does not lead to an excessive slurry viscosity. However, a greater clay content may be allowed if the formation geological characteristics are shown to be adequate to avoid injectivity impairment, slow pressure decay or excessive treatment pressures. Hydrocarbon content of the sand or viscosity of the muds and slops. The hydrocarbon content limit is related to the viscosity of the hydrocarbon. For example, if the viscous fluids to be disposed contain more that 10% by volume of viscous crude oil, having an oil viscosity greater than 1000 cp, the slurry is diluted with make-up water to comprise a maximum of about 10% oil content by volume. Different limits apply for low viscosity oils and emulsified waste materials. The geological characteristics of the target stratum also is a factor. A courser-grained stratum having a mean grain diamter of greater than about 150 microns will accommodate without formation impairment a higher oil content than will a finer-grained stratum. Formation grain size and stress state. SFI is most effective and secure in strata where there are no large pre-existing tectonic stresses that could lead to wellbore impairment or formation shearing during the injection treatment. Specifically, the ration of the major and minor principal stresses should be less than about 3.0. Formation geology. SFI is conducted in target zones comprising sandstones, limestones, chalk or diatomite. As already discussed, the most favorable target stratum is a permeable uncemented sandstone overlain by a sequence of impermeable shales and permeable beds. These geological characteristics dictate aspects of the slurry design, including grain size and slurry content. Heterogeneous effective stress and permeability distribution in the formation. Geological and rock mechanics studies must demonstrate that the stress state is acceptable and that there are not likely to be highly heterogeneous stress distributions that could he detrimental; to SFI activity. Accordingly, the permeability characteristics of the target zone must also be demonstrated not to be excessively heterogeneous in the lateral or vertical directions. The slurry density, waste concentrations and rheology must minimize the development of long term formation stress and pressure gradients in the target zone. Repeated loading and unloading of rock stresses. SFI generates substantial load changes with each cycle. The purpose of pressure and deformation monitoring is partially to ensure that these do not become so large as to lead to wellbore or formation impairment. The slurry density, waste concentrations and rheology must minimize the development of long term formation stress and pressure gradients in the target zone. Wellbore cement quality. Before a pre-existing well is adapted for SFI use, the cement between the casing and the rock must be shown to be of a sufficient quality to assure that upward inter-formation leakage is unlikely to occur. The slurry density and waste concentrations and compositions must be designed in order to minimize cement cracking and deterioration of the casing cement bond and deterioration of the formation cement bond. Preferably, a cement bond log is performed and examined. If a new dedicated SFI well is prepared, a specific approach to cementation is taken using a cement formulation with low shrinkage and a good bond potential. Wellbore completions quality (casing, perfing etc.). The SFI wellbore must pass pressure tests demonstrating that it can withstand pressures higher than the maximum to be encountered during slurry injection operations. The design of the perforations should be in accordance with the guidelines stated above relating to grain size, with the perforations having a diameter about five times the diameter of the largest grain size that will pass the waste screening process. Perforations may be fully phased and the length and location of the perforated interval will be dictated by the geological parameters of the target zone so as to minimize the risk of wellbore impairment and to maximize access to high permeability rock in the formation. The slurry density and waste concentration and composition must be designed to minimize blockage of the perforations, plugging of the injection tubing, plugging of the well across the injection interval and to minimize back flow of waste material during interinjection shut down periods. In one version, the slurry can incorporate a high percentage of shale chips and clays, approximately 50%-90% of the solids portion by volume, in order to reduce the risk of poor-quality leachate generation within the target stratum. With this approach, once the waste material is compacted at depth, the solidified material possess a reduced permeability with a high adsorptive capacity. This method is particularly useful for disposing of low or intermediate-level radioactive wastes or other hazardous wastes. The slurry mixture may be tested prior to injection for the reduction in its permeability. The tests may comprise quantitative analysis using high-pressure uniaxial and/or triaxial compressibility cells with creep testing and fluid flow rate testing methods. To test the ultimate permeability of a particular cementitious slurry, a sample of the mixed slurry is placed in a test chamber and subjected to the overburden stress, pore pressure and temperature it will experience at depth. Compaction is allowed to occur by making provision for the drainage of expelled pore liquid, simulating the densification process at depth. These conditions are maintained on the test sample for a period of no less than two weeks, at which time an axial permeability test is carried out in the same manner. The axial permeability test consists of determining the flow velocity through the test sample when a water pressure difference is imposed between the top and bottom of the compacted cementitious solid material. To be effective as a means of isolating the wastes from surrounding groundwater flow, the permeability should be no more than 1% of the average permeability of the target strata. The slurry is also formulated to ensure rapid bleed-off of pressure during injection, so that fracturing does not propagate far, either vertically or horizontally. The typical injection well 68 is similar to a conventional oil well, but with a larger diameter to accommodate a lining comprising a substantially full-length concrete production casing 3 and, where appropriate, a cemented surface casing 4. The well will not deviate from the vertical by substantially more than about 45 degrees. The lower portion of the well casing, comprising a length of at least 3 meters, is perforated. The well is prepared using controlled drilling practices (rather than conventional boring). During drilling, a high rate of mud circulation is employed to reduce filter cake buildup and to keep the bore clean. A heavy grade casing is employed for the surface and production drill strings. Conveniently, the casing surface is roughened by sandblasting or the like prior to insertion, to enhance concrete bonding. An epoxy/sand coated casing may also be employed. After drilling, the well bore is cleaned by flushing with conditioned mud to remove drill cuttings and filter cake from the bore. Conveniently, the mud flush can employ about double the usual quantity of mud, followed by about 5 m.sup.3 of scavenger slurry immediately prior to cementing. A low shrinkage, pliable and expandable cement should be used for cementing the well, in order that the repeated and sequential applications of pressure during the SFI process does not fracture or crack the concrete layer. A concrete lining extend from about the well bottom to at least above the 10 lowermost casing joints (assuming the use of conventional 10 m length casing units). In the cementing process, casing scrapers and centralizers are used to achieve a better cement bond with the casing. As well, the casing should be rotated and reciprocated vertically during cementing. The cement may be prepared using a continuous batch mixing method to achieve a generally constant cement weight. The cement should not bear weight for a period of time following cementing. When the concrete has cured, the casing and lining are perforated by means of low impact perforation techniques or cutting or slotting techniques. The perforation interval should not exceed 10 meters in order to sustain high injection pressures and rates. The perforation density is preferably about 20 holes/meter and covers between at least about 90.degree. to 120.degree. phasing (and preferably is fully phased) to ensure good radial distribution around the well. An open-bottom injection tubing string 5 is lowered into the hole and there retained within a metal casing-packer 6 in such a manner that the lower part of the tubing string protrudes no more than 3 meters below the packer and at least 1meter above the uppermost perforation. During installation of the tubing string, a hole-bottom electronic pressure gauge 7 is installed to measure pressure of the fluid within the tubing near the bottom of the hole. The gauge is submersible, and may comprise a strain gauge, vibrating wire or vibrating strip-type gauge, capable of measuring bottom-hole pressure from 7-70 Mpa. The gauge is installed in a stainless steel saddle 8 welded to the tubing string 0.5 to 3 meters above the top of the packer. The sensor provides an electronic signal to the surface through a multiconductor, high-pressure cable 9 strapped to the outside of the tubing and installed along with it. The gauge is employed to measure fluid pressure of the slurry during and after the injection. A second electronic pressure sensor or continuous pressure recording device 10 is installed within the annular space between the casing and the tubing at the wellhead. The slurry may be formed either in advance and trucked to the site in the pumping truck 12, or prepared on site. The density of the slurry is monitored either at the pumping truck exit line 14 or at the exit line from the slurry formation apparatus. Where the slurry is mixed on site, the quantities of waste solids, aqueous carrier, additive solids and waste liquids entering the slurry are monitored. Prior to slurry injection, it is desirable to conduct pressure fall-off and step-rate injectivity tests within the injection well in order to assess the formation flow behavior (formation permeability and transmissivity), formation geomechanical behavior (compressibility, fracture behavior, stress state), and potential slurry injectivity into the reservoir. The information obtained from this procedure is used both to optimize the injection protocol and during the slurry injection procedure to determine if anomalies are occurring. In particular, these tests assess whether the formation is suitable for long term (greater than about 2 months) and generally continuous (greater than 4 hours/day) injection. FIG. 4 illustrates a typical desirable pressure fall-off curve analysis, wherein the X-axis represents bottom-hole pressure and the Y-axis represents time, with the resulting curve representing pressure fall-off over time. An extrapolated formation pressure level is shown for comparison. The step-rate test also permits the determination of the required fracture extension rate and fracture extension pressure required for carrying out the SFI method. An example of a step-rate test is shown in FIG. 5, wherein the fracture-opening pressure is shown as a constant, with the bottom-hole pressure increasing in response to increasing injection rates. Slurry is injected into the well in a series of one or more injection episodes of between about 3-30 hours each. The injection pressure of the slurry is sufficient to overcome the parting pressure of the formation. The natural pressure in the porous strata will be far less than the water pressure in the slurry, proving a strong natural gradient that draws the water away, leaving the solids component behind. The individual injection episodes are separated by interinjection periods of between 5 and 100 hours, and preferably between 8 and 14 hours, depending on the response of the stratum. Each injection episode is initiated by pumping solids-free liquid through the system at a pressure sufficient to initiate fracturing of the target stratum. Typically, the flow rate during this stage will be about 1.5 m.sup.3 /min. Solids are gradually introduced to the flowing mixture, and the target solids content is built up over 15-20 minutes. At the end of each injection episode, the solids content of the slurry is gradually diminished, the well is flushed with clear liquid and the well is shut in under pressure (i.e., while pumping). The wellhead and well bottom pressures are recorded at this stage and periodically thereafter throughout the interinjection episode. The interinjection shut in period is preferably between 10 and 72 hours. The shut in period permits the stress and localized pressure fields generated during the injection period to redistribute and dissipate. In one preferred regime, the SFI process commences with an initial injection of carrier liquid (typically water) at a high rate to initiate hydraulic fracturing within the target formation. The formation pressure will as a result fall to a stable injection level as a result of bleed-off. A slurry is gradually introduced into the carrier until the selected target concentration is reached, to achieve SFI at an injection pressure (Press.sub.inj) of between 1.05-1.4 times the overburden pressure, depending on the site and slurry properties. The injection episode is then carried on for between about 4 to 14 hours. Pressure variations of between 5-10% may occur in this period. During this period, an increased formation pressure results in the vicinity of the injection well. At the termination of the injection episode, the slurry is gradually replaced with a clear carrier liquid, with about 5-40 m.sup.3 being flushed through the system. The well is then shut-in during an interinjection period, resulting in a sharp drop in formation pressure. During this period, liquid flow within the formation typically consists largely of porous medium flow rather than the fracture flow which characterizes the injection episode. The entire process is repeated 12-24 hours later. Preferably, the entire injection/interinjection cycle is approximately 24 hours duration, resulting in a convenient daily cycle time. The daily injection cycle may be repeated about 5-10 times, followed by a prolonged interinjection period of about 2-3 days, following which the injection cycle may be repeated a further 5-10 times, and so forth until the calculated storage volume is generally fully saturated. This strategy permits a long term (2 months or more) injection regime. The cyclical injection episodes facilitate fracture re-initiation and propagation. FIG. 6 is a graph illustrating a typical 24 hour SFI cycle, with the vertical axis comprising bottom-hole pressure and the horizontal axis signifying time. A successful SFI strategy will result in the wastes being deposited progressively outwardly from the injection well, while maintaining hydraulic isolation. Where the SFI method is used for the disposal of viscous fluids such as oily wastes, municipal sludges, or industrial wastes, the slurry is injected into an appropriate target stratum in such a manner that the formation flow behavior (i.e. permeability and transmissivity) is not significantly impaired and permeability blockage is minimized. This minimizes fractures that tend to propagate out of the target stratum and breach hydraulic isolation. Mathematical analysis of the pressure and surface deformation data may be conducted to determine the orientation and distribution of the injected slurry. This analysis assists in evaluating containment of the material within the disposal formation. The injection well and the region surrounding the well are monitored by means of surface and subsurface techniques to optimize infectivity and to track formation response to the injected solids. Appropriate monitoring permits optimization of: the total slurry volume to be injected; the injectivity rate; the slurry density and composition; the duration of the injection and inter-injection episodes and the total period of use of the injection well. These factors are determined as follows: The pressure responses of the formation during and after injection are analyzed to give the formation parameters, including permeability, transmissivity and radius of the altered zone. These parameters are tracked over time to ensure that the formation is responding in an optimal manner, if the formation is not responding well, direct alterations of the injection strategy may be made, including alteration of injection rates and periods. The slurry formulation may also be changed to increase the pressure decay rate. In general, if formation blockage or excessive pressurization appear to be occurring, the content of slops and mud will be diminished in favour of sand and water and the volume and duration of the clear water pre-treatment and post-flush will be increased. Waste pod monitoring data are also analyzed to provide a quantitative assessment of the hydraulic isolation of the waste pod within the formation during and after SFI, as well as wellbore integrity. For example, surface deformation data are analyzed to determine the shape and location of the solids injected zone at depth. The zone is determined to be unacceptable and hydraulic isolation is in question, then slurry formulation changes are instituted or the formation around the well is deemed full. The analysis can also be based on formation pressure data analysis and geophysical tracer logging data analysis. Geophysical logging techniques are used periodically to evaluate hydraulic isolation of the disposal formation during SFI operations. Experience has shown that near-wellbore formation flow and stress state changes occur readily during SFI operations. Radioactive tracer log and temperature log data collected concurrently provide a quantitative assessment of the hydrologic isolation of the formation and near well containment of the waste body. Additionally, pressure characteristics within monitoring wells in the region around the injection well may be taken into account. An injection episode should be terminated if the well-bottom pressure within a remote monitoring well (more than 50 m distance) climbs by about 25% of its original pressure. As well, any particular information that is available regarding the structure and seismic characteristics of the target stratum may be taken into account. For example, unexpected microseismic activity or anomalous pressure response in an adjacent monitoring well can result in a modification of one or more the parameters set out above. An injection strategy suitable for use with predominantly particulate waste streams is as follows: The fracture pressure and extension values are determined by the step-wise injection tests and pressure fall-off tests described above. Slop may be injected during the procedure to facilitate the sand injection, to avoid frac tip screen-outs, wellbore sanding and other clogging problems. Slop may be injected at the following stages: For the latter slop injection procedure, a slug of slop (approx. 10 m.sup.3) is injected at the rate of 10-15 m.sup.3 /hr., until the wellbottom pressure recovers to normal. During this procedure, the sand concentration in the slurry is reduced. The maximum slop injection should not exceed about 60 m.sup.3 /day. An SFI strategy for disposal of predominantly viscous liquids is as follows: In this regime, sand may be introduced into the slurry to facilitate the slop injection, by minimizing injection pressure surge effects, avoidance of formation and wellbore plugging and other problems. Typically, sand and slop are injected in a series of alternating stages. For example, a slop slurry stage incorporating 30 m.sup.3 slop material may be alternated with 20 m.sup.3 sand material mixed with sufficient water to generate a suitable slurry. These two stages may be alternated until the daily slop injection target is reached. The injection cycle may be concluded with a 20-50 m.sup.3 sand-based slurry injection, followed by a clear flush of approximately 50 m.sup.3 water. An example of a typical injection protocol developed for a site in East-Central Alberta is: Target Stratum Description: 14 m. thick, 30% porosity depleted sandstone reservoir; compressibility of 10 kPa or higher; flat-lying (horizontal) of great lateral extent (>1 km in all directions). Description of overlying strata: directly overlain by 100 m alternating shales and clayey silts; permeability less than 10 mD, except for several thin stringers (1-3 m) of permeability >100 mD, for lateral bleed-off of any vertically migrating fluid; from 100 m above the target to 250 m above the target, a continuous bed of ductile shale (horizontal) of extremely low permeability. Slurry Composition: The carrier phase is waste water (weak brine) produced along with oil from an adjacent oil filed (70%-80% of slurry volume). The solid waste is fine-grained sand with a small fraction of clay (<1-2%) contaminated with heavy oil (15-30% of slurry volume). Also, the slurry may include 0-25% of "slops", i.e., ground surface wastes, including soil, sand or water mixed with spilled oil. Injection Pressure: Measured at hole bottom, no greater than 140% of overburden stress. Injection Rate: from 1.1 to 1.8 m.sup.3 /min. of slurry. Total Slurry Volume: Max 800 m.sup.3 in a 24 hour period. Total for well--100,000 m.sup.3 of 20% solids content for a total of 20,000 m.sup.3 of sand. Average Injection Duration: 10 hours Average Interinjection Period: 14hours Maximum Surface Uplift: less than 1 mm for each episode. Monitoring strategy: Four pressure monitoring wells in a square, each well being 150 m from the injections well; 12 tilt meters arranged in a first circle of 8 placed at 150 m radius around the injection well and a second circle of 4 at 300 m radius from the injection well. Annular casing pressure, tubing wellhead pressure and tubing well bottom pressure recorded during injection and interinjection episodes. Injection volumes, rates and solids contents measured and recorded. In most applications, additional variables should be monitored and recorded, in particular slurry density, pressure, volume and composition. The pressure data from the injection and monitoring wells are used, together with step-rate injection test data, to evaluate the waste emplacement process. In general, the process is accompanied by a suite of monitoring procedures conducted before, during and after the injection process, as follows: i) Monitoring the slurry injection and emplacement by means of measurements of wellbottom hole pressure ("BHP") within the injection wells to assess formation pressure response to the waste injection, as well as permitting pressure fall-off tests and assessment of SFI and formation mechanics. The BHP sensors should have a minimum 0.1% full scope accuracy, very low hysteresis and thermal zero-shift and high resolution (approx. 0.025% FRO). These tests are typically conducted at 5 minute intervals during both interinjection and injection episodes. Further, a 5-60 second scan rate may be used for the first 60 minutes after the daily shut-in. ii) Monitoring BHP within observation wells displaced from the injection wells within about 400 meters to provide assessment of formation pressure gradients and SFI mechanics. The observation well BHP sensors should have the same characteristics as the injection well BHP sensor, and the minimum scan rate is typically 15 minutes. Observation well BHP monitoring is typically conducted in projects involving greater than 3000 m.sup.3 /month or 10,000 m.sup.3 /year. iii) Step rate injection tests ("SRT") conducted within the injection well, to assess fracture extension rate and formation pressure response, as well as closure stress gradient and waste containment within the formation. A baseline SRT is performed prior to the start of the SFI process and is repeated after every 3000-5000 m.sup.3 of wastes have been injected, or at the end of the project. iv) Fluid level measurements within the offset monitoring wells to assess distribution of pressure gradients within the waste emplacement zone and to provide a measurement of waste containment. Baseline levels are established at the start of the SFI process and the test is repeated daily during SFI injection. v) Tracer logs within the injection well, to determine the extent of hydraulic isolation of the formation and wellbore during the injection process and an assessment of fracture orientation within the target formation. A preliminary baseline is established, and the test is repeated after every 3000-5000 m.sup.3 of wastes or at the end of the project. vi) monitoring of surface tiltmeter data generated in the region about the wellhead; to assess the fracture orientation and azimuth, as well as permitting a reconstruction of fracture geometry, horizontal and vertical dimensions and spread of the waste body within the target formation and the rate of change of same, and deformation within the formation, as well as a further assessment of the SFI mechanics. A baseline is established, and tests are repeated every 30 minutes throughout the project duration. Normally, 2-3 data sets per month are analyzed. vii) Injection parameter monitoring (real time recording of injection pressures at wellhead and wellbottom, casing pressure, injection rate, injection volumes and slurry density) to permit a correlation of formation response with the SFI operating parameters. Monitoring is performed continuously, with a minimum scan rate of 1 second. Data is recorded to disk about every 5 minutes. viii) Material sampling of the slurry is conduced regularly and frequently to accommodate various local regulatory requirements. Typically, this occurs weekly, with analysis performed monthly. The monitoring strategy in any given regime is determined in part by the volume and type of waste to be disposed, the geological characteristics of the target stratum, the condition and completion of the wellbore, and the monitoring objectives, including any regulatory requirements. Alterations in large-scale permeability, excessive pressure build-up, abnormal fracture pressure, too-rapid pressure decay or other anomalous reservoir responses are identified and analyzed to decide if these present problems for the continuation of the injection process in a particular well. For example, if the monitoring wells display sudden pressure responses, this would indicate that a discrete fracture plane is interacting with the remote wells, thereby suggesting that the fracture bleed-off is being impaired by permeability blockage. If this is the case, or if other anomalous responses are noted, the slurry design and the injection strategy are altered to rectify the problem and remain within the realm of rapid bleed-off and near-wellbore solids emplacement. Injection procedures may be adjusted appropriately in the event that well-bottom pressure is decaying too slowly, if it appears that solids are being transported out of the target stratum, if the monitoring wells show anomalous pressure responses, or if other monitoring reveals substantive formation containment impairment. For example, slow strain relaxation and pressure decay may be due to excessive fines in the slurry, too large a volume injected within each episode or too short an interval between injection episodes. The response of the reservoir stratum and overlying rock to the slurry injection may be assessed by way of the surface deformation data, in combination with the previously-determined capacity of the reservoir. The reservoir response may be determined from this data as follows: a) The tiltmeter response data over the time period of interest (i.e. 1 hr. to several days) is examined to ensure against anomalous noise signals in the data base. b) The magnitude and direction of the surface tilt responses provide input to a computer programmed to analyze the tiltmeter data. c) The analysis provides an estimate of the size and shape of the zone of solids emplaced at depth over the time period analyzed. A variety of monitoring tools may be used in addition to surface deformation measurement to assess the mechanical formation response to the injection. Changing formation response can result in changing and multiple flow regimes, that in turn may require alteration to the SFI strategy and regime. Typical changes that may be monitored by the methods described herein include changes in formation compressibility and stress state, rate of dynamic fracture propagation and orientation (dip, azimuth), dynamic in situ pressures and stress gradient formations and stress dissipation, formation mechanical deformation and yielding, overburden straining and bending, and asymmetric distribution of waste material around the injection well. Confirmation that the injection process is proceeding properly is obtained by insuring that there is a rough balance between the solids volume input and the volume of deformation, by comparing known input to the results of the mathematical analysis. The surface uplift data allow discrimination between vertical and horizontal fracture orientations by virtue of the magnitude and direction of the tilt vectors from an array of 10-20 tiltmeters positioned around the injection well. This indicates whether vertical or horizontal material transport away from the wellbore may be occurring. In general, the tilt response for long-term injection wells should be dominated by horizontal fracturing components. The tilt data can be analyzed in terms of total deformation to give limits on the extent of the deformation in the reservoir, and by this means the approximate radial and preferably vertical extent of the emplacement zone can be assessed. Also, the tilt or deformation data can be used directly to demonstrate that the ground surface deformations are small and meet limits which might be set by regulatory guidelines. The time-dependent decay of surface tilt changes and internal pressures provides direct evidence of the speed by which the reservoir and the overlying rocks are responding to the volumetric and pressure changes induced by the injection activity. If deformations continue slowly for many days after an injection episode, combined with a slow pressure decay rate, it is proof that the reservoir is approaching capacity, that permeability has become blocked, or that injectate has migrated to a zone of low fluid transmissivity. Conversely, rapid decay and cessation of deformation is evidence that the reservoir is responding as expected with efficient bleed-off and solids localization near the wellbore. These measures over time are used directly to adjust the slurry design and the injection strategy to achieve the best possible reservoir response to the injection. Mathematical analysis of the pressure and tilt data allows for reconstruction of the size and distribution of the injected material. The method may also include microseismic monitoring of the surrounding region to assess the injection process. Such monitoring involves detecting and analyzing small seismic disturbances associated with rock deformation that accompanies the slurry injection. Microseismic monitoring is used in conjunction with the surface deformation and uplift data to determine the approximate dimensions horizontally and vertically of the solids emplacement zone. The locations of microseismic events are plotted three-dimensionally over time, and resulting identification of the microseismic emission field identifies the size and growth rate of the solids emplacement zone. If large amounts of microseismic activity are observed high above or far away from the perforation locations in the well, the nature of the signals is analyzed along with the surface uplift response to the injection, to ensure that solids are not migrating out of the injection zone. If the microseismic emissions continue beyond the time of active injection by several hours or days, this is taken as evidence that pressures are not decaying sufficiently rapidly or have entered a zone of lower permeability. The data from microseismic monitoring are combined with other measures (tilt, volume, rate, pressures) to permit the injection process to be controlled and optimized continuously. The monitoring data may be used to perform the following: The nature and extent of monitoring is a function of the volume of waste to be injected, the geological characteristics of the target stratum, the nature of the waste material, the wellbore characteristics, and the monitoring objectives (e.g., regulatory, personnel safety, etc.). The monitoring data are analyzed to carry out the operations described above with a computer linked to the monitoring instruments described above and programmed to perform the following operations: ##STR1## These operations permit the rapid assessment of events within the reservoir, and permit the dimensions of the solids containment area to be evaluated. This in turn permits the user to demonstrate that the solids are being appropriately contained within the target stratum. Post-injection monitoring is carried out to ensure that the solid wastes are generally contained within the target stratum. The surface deformation and microseismic monitoring described above is carried out subsequent to the injection, typically for a period of several days. If the site has been properly selected and the injection properly carried out, the post-injection monitoring should disclose stable underground conditions. If surface or subsurface instability continues after the injection terminates (allowing for a period of approximately one week for stabilization to be achieved), this is evidence that the solids are potentially migrating,out of the target zone. Surface deformation and microseismic analysis as described above is also deployed in the post-injection period to determine on a periodic basis the positioning of the solids emplacement zone, to ensure that this zone is not expanding beyond set limits and is not potentially communicating with potable water. Referring to FIGS. 2 and 3, the slurry formation and injection apparatus comprises in general terms a feed hopper 30, mixing-averaging apparatus 32 and injection pump apparatus 34. A conveyor 36 transports waste material from the hopper to the mixing-averaging apparatus and comprises a rotatably-driven auger 37 housed within an elongate chamber 38. A water supply tank 39, linked by pipe 40 to the mixing-averaging apparatus, provides a steady high-pressure (approx. 200 psi) source of water for the creation of the slurry. A pipe 48 transports the slurry from the mixing-averaging apparatus to the pump 34. The feed hopper 30 comprises waste-receiving means and is utilized for wastes that consist of oil or sludge-bearing sand, or the like. For certain other, more fluid types of wastes, the hopper may be dispensed with and the wastes deposited directly into the mixing-averaging apparatus. The hopper is designed to receive a load of between 8 and 20 cubic meters of sand. The mixing-averaging apparatus comprises a particle sizing means to screen out oversized particles, consisting of a reciprocally-driven multilevel screen deck 50 onto which wastes are deposited from the conveyor 36. The individual screens within the deck are adjustable and removable to optimize slurry composition for particular injection conditions. A water sprayer 52 is positioned to direct a high-pressure stream of water at the wastes as they exit the conveyor 36. The sprayers are linked to the pipe 40. The screen deck is comprised of three levels of screens, each having a variable matrix size. Waste material is dumped onto the uppermost screen deck 58 either directly or from the conveyor 36. The action of the spray jet and the shaking of the screens serves to remove particles having a size greater than 0.25 to 1 cm. and foreign objects in the waste stream. These oversized particles are either crushed by a stand-alone crusher 60, to be fed back into the waste stream, or are collected and disposed of by other means, not shown. The screened wastes fall from the screen deck into a slurry averaging and mixing tank 61 that supports therein dual rotatably driven mixing screw augers 62 and 63. Additives and agents may be added directly into the tank 61, if required. A pipe 64 leads from the base of the slurry averaging tank into the booster pump apparatus 34, which pressurizes the slurry and discharges it under pressure through a discharge pipe 66 into the well 68. The various components of the system are driven by conventional variable speed hydraulic motors 70. These in turn are linked to a control means 72 which permits control over the inputs into the slurry-production means and over the slurry design. The control means, shown schematically in FIG. 3, receives input from a real-time monitoring system that monitors, records and visually displays the injection parameters of slurry density, injection rate, surface injection pressures, injected volumes and slurry solids concentration. The monitoring system consists of: The control means is adapted to maintain an even slurry density and delivery rate and pressure. The means by which this is achieved comprise generally conventional feedback means. The apparatus further includes a computer operatively linked to the surface uplift indicators and, optionally, to the micro seismographs described above, and programmed to assess the localization and movement of the solids embedment zone in the manner described above. Although the present invention has been described by way of preferred embodiments, it will readily be seen by those skilled in the art to which this invention pertains that numerous departures, variations, etc. of the invention may be made, without departing from the spirit and scope of the invention, as defined in the following Claims.
	claims	1. A collimator for a radiation imaging detector, the collimator comprising:a plurality of adjustable segments;a plurality of collimator holes within each of the plurality of adjustable segments, and wherein the plurality of adjustable segments are configured to move independently of a detector to adjust a field of view of the collimator holes; anda shielding member between each of the plurality of adjustable segments. 2. The collimator of claim 1, wherein the plurality of adjustable segments are configured for swiveling about an axis parallel to an axis of rotation about a patient. 3. The collimator of claim 1, wherein the plurality of adjustable segments are independently movable from each of the other plurality of adjustable segments. 4. The collimator of claim 1, wherein at least two of the plurality of segments include collimator holes slanted at different angles. 5. The collimator of claim 1, wherein the plurality of adjustable segments pivot. 6. The collimator of claim 5, wherein at least one of the plurality of adjustable segments is pivoted at an angle different than the angle of at least one of the other plurality of adjustable segments. 7. The collimator of claim 1, wherein each of the plurality of adjustable segments includes a curved end and wherein the shielding member includes a complementary curved portion. 8. The collimator of claim 1, wherein the plurality of collimator holes are pre-slanted. 9. The collimator of claim 1, wherein the plurality of adjustable segments include collimator holes having different lengths. 10. A nuclear medicine (NM) imaging system comprising:a gantry;at least one imaging detector supported on the gantry and configured to rotate about the gantry defining an axis of rotation;a segmented collimator connected to the at least one imaging detector, the segmented collimator having a plurality of movable segments configured to move independently of the at least one imaging detector, wherein the movable segments are independently controllable;a controller configured to control movement of the movable segments; andan image reconstruction module configured to reconstruct an image from data acquired from the at least one imaging detector, wherein the image reconstruction module is configured to compute a probability that image voxels are obtained from a projection for a plurality of at least one of segments, detector or gantry angle combinations. 11. The NM imaging system of claim 10, wherein the plurality of movable segments are configured to swivel about an axis parallel to the axis of rotation. 12. The NM imaging system of claim 10, wherein the at least one imaging detector is pivotally connected to the gantry and configured for movement independent from the movement of the plurality of segments. 13. The NM imaging system of claim 10, wherein at least two of the plurality of segments are positioned at different swivel angles for imaging. 14. The NM imaging system of claim 10, wherein the at least one imaging detector comprises a Single Photon Emission Computed Tomography (SPECT) camera. 15. The NM imaging system of claim 10, wherein the plurality of segments are configured for sweeping operating at each of a plurality of positions of the at least one imaging detector. 16. The NM imaging system of claim 10, wherein the collimator comprises pre-slanted holes. 17. A method for collimating a detector of an imaging system, the method comprising:configuring a segmented collimator to provide movement of each of a plurality of segments independently of a detector to adjust a field of view of collimator holes of the plurality of segments;coupling the segmented collimator to the detector of the imaging system; andproviding a controller to control the imaging system to move at least one of the plurality of segments, the detector or a gantry of the imaging system to which the detector is coupled, wherein the controlling comprises using acquired scan acquisition information for a current scan to control movement of the segmented collimator. 18. The method of claim 17, wherein the controlling comprises one of swiveling the plurality of segments, pivoting the detector or rotating the detector about the gantry. 19. The method of claim 17, wherein the controlling comprises using at least one of (i) anatomical information or (ii) prior information for a patient to define a scan pattern to control movement of the segmented collimator. 20. The method of claim 17, wherein the controlling comprises changing a defined scan pattern based on the acquired scan information, wherein the acquired scan information comprises one of raw data counts or an initial image reconstruction.
051909901	summary	BACKGROUND OF THE INVENTION This invention was supported in part by research grant number DE09322-01 to the American Dental Association Health Foundation from the National Institute of Dental Research. This invention relates to the field of shielding healthy tissues from radiation damage during radiotherapy for malignant conditions. It also relates particularly to the field of such shielding where the tissues to be shielded are of irregular conformation and/or associated with metallic restorations or prostheses, as in the mouth. Approximately 30,000 people were diagnosed with some form of oral cancer in 1985, accounting for more than 3% of all patients with cancer and 3% of cancer related deaths (American Cancer Society, 1985). Treatment of oral malignancies is a great challenge to radiotherapists because of their potential curability. Treatment of head and neck tumors by electron, x-, or gamma-ray teletherapy is a well established and highly successful modality. S. Benak, F. Buschke, and M. Galanta, "Treatment of Carcinoma of the Oral Cavity," Radiology 96, 137-143 (1970), T. L. Phillips, and S. Benak, "Radiation Modalities in Treatment of Cancer of the Oral Cavity," J. Prosthet. Dent. 27, 413 (1972); J. A. Toljanic, and V. W. Saunders, "Radiation Therapy and Management of the Irradiated Patient," J. Prosthet. Dent. 52, 852 (1984). The ease of access, localization of malignancies, and relatively high responsiveness of these tumors to radiation leads to encouraging treatment prognoses. One of the major complications of head and neck radiotherapy is the post-irradiation damage to healthy tissues in front of, adjacent to, or beyond the treated tumors. This latent radiation damage to nonmalignant tissues can range in severity from slight post-treatment discomfort to life-threatening necrosis. Manifestations of radiation damage include dry mouth (xerostomia), loss of taste, changes in oral microflora and salivary chemistry, erythema and ulceration of oral mucosa, glossitis and edema of the tongue, moniliasis of the lips, salivary gland dysfunction and edema, dysphagia, muscle fibrosis, and osteonecrosis. J. Beumer, S. Silverman, and S. B. Benak, "Hard and Soft Tissue Necrosis Following Radiation Therapy for Oral Cancer," J. Prosthet. Dent. 27:640-644 (1972); J. Beumer, T. R. Curtis, and R. Harrison, "Radiation Therapy of the Oral Cavity: Sequelae and Management," Part 1, Head and Neck Surgery, 1:301-312 (1979); D. L. Larson, "Management of Complications of Radiotherapy of the Head and Neck," Surgical Clinics of North America 66:169-182 (1986); S. Driezen, L. R. Brown, S. Handler, and B. M. Levy, "Radiation-Induced Xerostomia in Cancer Patients, Effect on Salivary and Serum Electrolytes," Cancer 38, 273-278 (1976); S. Driezen, T. E. Daly, J. B. Drane, and L. R. Brown, "Oral Complications of Cancer Radiotherapy," Postgrad. Med. 61, 85-92 (1977); cited by I. L. Shannon, "Management of Head and Neck Irradiated Patients," Adv. Physiol Sci. Vol. 28, Saliva and Salivation (1980). Diminished salivary function is a very common post-irradiation condition which often leads to accelerated tooth decay or "radiation caries". J. Beumer, S. Silverman, and S. B. Benak, "Hard and Soft Tissue Necroses Following Radiation Therapy for Oral Cancer," J. Prosthet. Dent. 27:640-644 (1972); J. Beumer, T. R. Curtis, and R. Harrison, "Radiation Therapy of the Oral Cavity: Sequelae and Management," Part 1, Head and Neck Surgery 1:301-408 (1979), C. Fernandez, S. Master, B. Sarosh, and M. Turner, "Efficacy of Radiation Protection Prosthesis in Controlling Radiation Induced Xerostomia," J. Indian Dent. Assoc. 56:371-378 (1984). The severity of the above side effects on normal tissues has been reduced by a number of techniques including selection of the radiation source to have the least effect on normal surrounding or overlying tissues, careful positioning and collimation of the source beam, and shielding. In treatment of head and neck lesions with high-intensity radiation (teletherapy), an important aspect of the protection of healthy tissues has thus been manufactured and application of an individually customized prosthetic appliance, which is designed, modelled, and formed into a custom-made metal on plastic shield. Specifically, in treating lesions of the skin or oral tissues with electrons, photons, x-, or gamma-rays, shields and stents containing cast forms made from metals or alloys of high atomic density elements have been used to protect surrounding tissues. The fabrication of these appliances is a multi-step procedure often requiring the cooperative efforts of the radiotherapist and the dentist/prosthodontist. First, impressions are made of the intra- or extraoral treatment site and a plaster model of the tissues fabricated from these. A wax replica of the shielding prosthesis is fabricated on the plaster model and this is cast in polymerized acrylic by a lost-wax method to form the working stent. This stent is tried for fit and then hollowed out in the appropriate region for incorporation of a metal liner, which serves as the customized radiation shield. Molten lead or a low-temperature-melting alloy such as Lipowitz metal (50% bismuth, 26.7% lead, 3.3% tin, and 10% cadmium) is then poured and formed into the working polyacrylic stent, to form the shielding appliance, leaving a window exposing only the tissue being irradiated, where appropriate. After cooling, the metal casting is covered with an additional layer of polyacrylic. The completed appliance is then polished and adjusted to the final fit. Textbook of Radiotherapy, edited by G. H. Fletcher, second ed. (Philadelphia, Lea and Febiger, 1973). SUMMARY OF THE INVENTION The prior art method for shielding healthy tissues during high energy radiation therapy is slow and technique-intensive, and can add to patient discomfort and inconvenience during molding and fabrication of the shield. The difficulty encountered in fabricating a well-fitting stent particularly for head and neck cancer which can be comfortably worn during repeated treatments makes utilization of these techniques problematic for treatment facilities not having access to dental or maxillofacial services. The increasing utilization of outpatient clinics specializing in radiotherapy delivery enhances the need for shielding materials and techniques which can be much more easily fabricated and fitted in the treatment setting. It is an object of the present invention to provide radiation shielding and absorbing materials that can be more easily fabricated and fitted in clinics specializing in radiotherapy. These materials will then reduce the frequency, severity and morbidity of side effects from treatment of malignant diseases. It is an additional object of the present invention to provide protective prostheses which are of minimal weight, easy to adjust in the treatment room, easy to repair, easy to clean and easy to place and remove. The invention contemplates a material for preparation of a radiation shield for use during radiation therapy, where the material comprises a composite of non-radioactive non-toxic high atomic density metal or metal alloy spherical particles dispersed in a manually moldable elastomeric material, which will harden within a clinically acceptable time period to a firm or set structure which is semi-rigid in that it is elastomeric, i.e., deformable, but returns to its original conformation, when the deforming force is removed. Within the purview of the invention are mixtures of Sn-Sb, Ag-Cu, Cu-Al, Au-Cu, Sn-Bi, Ag-Pd, and stainless steel alloy spherical particle powders in a polymerizable elastomeric precursor or resin such as vinyl polysiloxane resin or silicone resin. Also contemplated as part of the invention are custom radiation shields formulated of this material. A further aspect of the invention is a method for fabricating such a custom shield which comprises mixing a powder of non-radioactive non-toxic high atomic density metal or metal alloy spherical particles with a manually moldable elastomeric precursor to form a moldable composite, custom fitting the moldable composite to the patient's tissues which are to be shielded during radiation therapy, and permitting the composite to harden. The inventive method for shielding healthy tissues during radiation therapy further comprises positioning the custom-fitted hardened radiation shield in the desired location on the patient's body prior to and during radiation treatment. It is a further aim of the present invention to provide an improved shielding stent material, device and method for intraoral and extraoral use in teletherapy. The inventive composite material is especially designed to allow for ease and speed of fabrication of shielding appliances. The material is formulated to be readily shaped to an individual anatomical form without excessive laboratory support, prosthetic expertise, or discomfort to the patient. Appliances can be fabricated from this material directly on the patient without the taking of preliminary impressions, heat-treating of acrylics, or casting of metals. The material can be formed and molded in the plastic state and chemically polymerized to form a firm elastomeric composite. This new material allows for much higher metallic loading fractions than are commonly used in filled resin formulations.
	abstract	The present invention provides a system, method, and program product for understanding, analyzing and troubleshooting performance issues in a data storage environment. More specifically, this invention is a system and method for preparing a trace of workload data for analysis by splitting information related to components on which the workload is experienced and by information type.
055725635	description	DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described with reference to the drawings. FIRST EMBODIMENT FIG. 1 is a vertical cross-sectional view illustrating a reflecting mirror unit according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line A--A shown in FIG. 1. As shown in FIG. 1, the present embodiment relates to a mirror unit (mirror chamber) for supporting a (reflecting) mirror 1, provided in the optical path of sheet-shaped synchrotron radiation light C, indicated by a broken-line arrow, between a synchrotron ring (not shown), serving as a light source, and a semiconductor exposure apparatus utilizing synchrotron radiation light (not shown), for spreading the synchrotron radiation light C in a direction perpendicular to the sheet plane of the synchrotron radiation. The inside of a chamber (also called a beam line) 6 for providing the optical path of the synchrotron radiation light C is maintained in a vacuum. FIG. 1 is the cross-sectional view of the mirror chamber taken along the optical axis of the synchrotron radiation light C. As shown in FIGS. 1 and 2, a front portion of the chamber 6 is connected to the synchrotron ring via a front flange 7a and a bellows 8a. A rear portion of the chamber 6 is connected to the exposure apparatus via a rear flange 7b and a bellows 8b, so that illuminating light is guided to the main body of the exposure apparatus. The front flange 7a and the rear flange 7b are fixed to the chamber 6 by a plurality of flange fixing bolts 10 and flange fixing nuts 11 via ring gaskets 9a and 9b for vacuum sealing, respectively. According to this configuration, the inside of the chamber 6 is maintained in an ultrahigh or high vacuum state. An opening 6a for mounting the mirror 1 is formed in a side of the chamber 6. The mirror 1 is disposed in the opening 6 such that a reflecting surface 1a of the mirror 1 is inside the chamber 6 (downward in FIG. 1). The back 1b of the mirror 1 is exposed to the outside (in the atmosphere). In order to spread the sheet-shaped synchrotron radiation light C in a direction perpendicular to the sheet plane of the synchrotron radiation, the reflecting surface 1a of the mirror 1 has the shape of a portion of a cylinder having a radius of about 100 m, so that the circumferential direction of the cylinder has an incident angle of about 10 mrad with respect to the optical axis of the synchrotron radiation light C. The cross section of the mirror 1 has the general shape of a block T. A frame 2 is fixed to the shoulder portions of the block T-shaped mirror 1 by a method capable of maintaining airtightness, such as brazing (see brazed portions B). The frame 2 has the shape of a plate having an opening capable of passing the mirror 1 through in its central portion. Annular edges (projections) for pressing a gasket 3 for vacuum sealing are formed on a surface opposite to the surface fixed to the mirror 1. The same annular edges (projections) as the annular edges of the frame 2 are formed on a surface of the chamber 6 at positions facing the edges of the frame 2. By compressing the gasket 3 by the edges formed on the surfaces of the chamber 6 and the frame 2, vacuum sealing is assured. In order to fix the mirror 1 to the chamber 6, and to press the gasket 3 so as to be sufficient for vacuum sealing, a mirror fixing member 4, serving as a frame-shaped mirror holding member, is fastened to the chamber 6 by a plurality of bolts 5. The mirror fixing member 4 is made of a relatively soft frame-shaped material, such as a plastic or the like, so as not to deform the reflecting surface 1a of the mirror 1 by an unbalanced force applied thereto. The mirror unit having the above-described configuration is disposed in the beam line between the synchrotron ring and the exposure apparatus so as to guide the radiation light to the exposure apparatus present at the downstream side while spreading the radiation light in a direction perpendicular to the sheet plane of the synchrotron radiation by the mirror 1. The relative position between the reflecting surface 1a of the mirror 1 and the radiation light is precisely aligned by driving the entire chamber 6 by a position-adjusting mechanism (not shown). It is possible to precisely align the reflecting surface 1a making the back 1b a reference by precisely measuring the shape of the mirror 1 before disposing the mirror 1 in the chamber 6. The relative movement of the chamber 6 with respect to the beam line during the alignment can be absorbed by the bellows 8a and 8b. While light having longer wavelengths of the radiation light is reflected by the reflecting surface 1a of the mirror 1, light having shorter wavelengths of the radiation light is absorbed by the mirror 1. The energy of the absorbed light is converted into heat, which is conducted through the mirror 1 and is radiated into the atmosphere from the back 1b of the mirror 1 exposed to the atmosphere. If the heat cannot be sufficiently radiated only by atmospheric cooling, a cooling-water channel may be formed in the back or the inside of the mirror 1, and cooling water may be circulated therein. If the reflecting surface 1a of the mirror 1 is damaged, the mirror 1 must be exchanged. When exchanging the mirror 1, the connected member comprising the mirror 1 and the frame 2 is exchanged. That is, the mirror fixing member 4 is first detached from the chamber 6, and then the connected member comprising the mirror 1 and the frame 2 is detached from the chamber 6. After replacing the gasket 3 with a new one, a new connected member comprising a mirror 1 and a frame 2 is fixed to the chamber 6 by the mirror fixing member 4. Thus, the exchange of the mirror 1 is completed. By previously providing a connected member comprising a mirror 1 and a frame 2 for exchange, the time required for the exchange can be shortened. According to the above-described configuration, since it is only necessary to provide a space for passing incident light and reflected light within the mirror chamber, it is possible to reduce the volume of the mirror chamber and to reduce the surface area of the inside of the chamber. As a result, only a relatively small evacuation capability is required for an evacuation system. In order to prevent the shape of the reflecting surface 1a of the mirror 1 from being deformed by heat, brazing of the mirror 1 and the frame 2 is performed before polishing the reflecting surface 1a. After the brazing, the surface of the mirror 1 is polished so as to provide a cylindrical surface. Although in the above-described embodiment the mirror 1 is fixed to the frame 2 by brazing, the mirror 1 may be fixed to the frame 2 by any other method provided that vacuum sealing can be realized. Although in the above-described embodiment a gasket is used for performing vacuum sealing, an O-ring may also be used. SECOND EMBODIMENT FIG. 3 is a vertical cross-sectional view ilustrating a mirror unit according to a second embodiment of the present invention. FIG. 4 is a cross-sectional view taken along line A--A shown in FIG. 3. As with the above-described first embodiment, the present embodiment relates to a mirror chamber for supporting a mirror, provided in the optical path of sheet-shaped synchrotron radiation light between a synchrotron ring, serving as a light source, and a semiconductor exposure apparatus utilizing synchrotron radiation light (not shown), for spreading the synchrotron radiation light in a direction perpendicular to the sheet plane of the synchrotron radiation by a cylindrical reflecting surface of the mirror. In FIGS. 3 and 4, the same components as those shown in FIGS. 1 and 2 are indicated by the same reference numerals, and a description will be omitted for components described in the first embodiment. As shown in FIGS. 3 and 4, a reflecting surface 1Xa of a mirror 1X has the shape of a portion of a cylinder having a radius of about 100 m so as to spread a sheet-shaped light beam in a direction perpendicular to the sheet plane of the synchrotron radiation. A mirror holding member (mirror mounting flange) 12 is fixed to side portions of the mirror 1X by means of brazing or the like so as to be integral with the mirror 1X (see brazed portions B). Brazing is performed so as to prevent leakage in order to maintain a vacuum within the chamber 8. The connected member comprising the mirror 1X and the mirror holding member 12 is disposed in the opening of the chamber 6 so that the reflecting surface 1Xa of the mirror 1X is present inside the chamber 6. In order to provide the chamber 6 with airtightness, annular edges for vacuum sealing are formed on a surface of the mirror holding member 12. By compressing the gasket 3 between the above-described edges and edges formed along the opening of the chamber 6 at positions facing the edges of the mirror holding member 12, vacuum sealing is assured. The mirror 1X is fixed to the chamber 6 by uniformly fastening the mirror holding member 12 along a circumference outside the sealed surface by a plurality of bolts 5. The mirror unit having the above-described configuration is disposed in the beam line between the synchrotron ring and the exposure apparatus so as to guide the radiation light to the exposure apparatus present at the downstream side while spreading the radiation light in a direction perpendicular to the sheet plane of the synchrotron radiation by the mirror 1X. The relative position between the reflecting surface 1Xa of the mirror 1X and the radiation light is precisely aligned by driving the entire chamber 6 by a position-adjusting mechanism (not shown). It is possible to precisely align the reflecting surface 1Xa making the back 1Xb a reference by precisely measuring the shape of the mirror 1X before disposing the mirror 1X in the chamber 6. The relative movement of the chamber 6 with respect to the beam line during the alignment can be absorbed by the bellows 8a and 8b. While light having longer wavelengths of the radiation light is reflected by the reflecting surface 1Xa of the mirror 1X, light having shorter wavelengths of the radiation light is absorbed by the mirror 1X. The energy of the absorbed light is converted into heat, which is conducted through the mirror 1X and is radiated into the atmosphere from the back 1Xb of the mirror 1X exposed to the atmosphere. If the heat cannot be sufficiently radiated only by atmospheric cooling, a cooling-water channel may be formed in the back 1Xb or the inside of the mirror 1X, and cooling water may be circulated therein. If the reflecting surface 1Xa of the mirror 1X is damaged, the mirror 1X must be exchanged. When exchanging the mirror 1X, the connected member comprising the mirror 1X and the mirror holding member 12 integrated by brazing is exchanged. That is, the connected member comprising the mirror 1X and the mirror holding member 12 is first detached by removing the fixing bolts 5, the gasket 3 is then exchanged, and a new connected member comprising a mirror 1X and a mirror holding member 12 is fixed to the chamber 6 by the fixing bolts 5. Thus, the exchange of the mirror 1X is completed. By previously providing a connected member comprising a mirror 1X and a mirror holding member 12 for exchange, the time required for the exchange can be shortened. According to the above-described configuration, since it is only necessary to provide a space for passing incident light and reflected light within the mirror chamber, it is possible to reduce the volume of the mirror chamber and to reduce the surface area of the inside of the chamber. As a result, only a relatively small evacuation capability is required for an evacuation system. In order to prevent the shape of the reflecting surface 1Xa of the mirror 1X from being deformed by heat, brazing of the mirror 1X and the mirror holding member 12 is performed before polishing the reflecting surface 1Xa. After the brazing, the surface of the mirror 1X is polished so as to provide a cylindrical surface. Although in the above-described embodiment the mirror 1X is fixed to the mirror holding member 12 by brazing, the mirror 1X may be fixed to the mirror holding member 12 by any other method provided that vacuum sealing can be realized. Although in the above-described embodiment a gasket is used for performing vacuum sealing, an O-ring may also be used. THIRD EMBODIMENT FIG. 5 is a vertical cross-sectional view illustrating a mirror unit according to a third embodiment of the present invention. FIG. 6 is a partially-cutaway perspective view of the mirror unit shown in FIG. 5. FIG. 7(a) is a cross-sectional view taken along line A--A shown in FIG. 5. FIG. 7(b) is an enlarged cross-sectional view illustrating a connected portion between a mirror and a mirror holding member. As the above-described first embodiment, the present embodiment relates to a mirror chamber for supporting a mirror, provided in the optical path of sheet-shaped synchrotron radiation light C between a synchrotron ring, serving as a light source, and a semiconductor exposure apparatus utilizing synchrotron radiation light (not shown), for spreading the synchrotron radiation light C in a direction perpendicular to the sheet plane of the synchrotron radiation by a cylindrical reflecting surface of the mirror. The inside of the chamber for providing the optical path of the synchrotron radiation light C is maintained in a vacuum. In FIGS. 5 through 7(b), the same components as those shown in FIGS. 1 and 2 are indicated by the same reference numerals, and a description will be omitted for components described in the first embodiment. As shown in FIGS. 5 through 7(b), a reflecting surface 1Ya of a mirror 1Y has the shape of a portion of a cylinder having a radius of about 100 m so as to spread a sheet-shaped light beam in a direction perpendicular to the sheet plane of the synchrotron radiation. A mirror holding member 13 is fixed to side portions of the mirror 1Y by means of brazing so as to be integral with the mirror 1Y (see brazed portions B). Brazing is performed so as not to provide leakage in order to maintain a vacuum within the chamber 6. Portions of the mirror holding member 13 brazed to the mirror 1Y provide an arch-shaped spring structure. The arch portion 14 absorbs deformation generated when the fastening force of the fixing bolts 5 for fixing the mirror holding member 13 to the chamber 6 is non-uniform, to prevent the reflecting surface 1Ya of the mirror 1Y from being deformed. The mirror holding member 13 is disposed in the opening of the chamber 6 so that the reflecting surface 1Ya of the mirror 1Y is present inside the chamber 6. In order to provide the chamber 6 with airtightness, annular edges 18 (see FIG. 7(b)) for vacuum sealing are formed on a surface of the mirror holding member 13. By compressing the gasket 3 between the above-described edges and edges 19 (see FIG. 7(b)) formed along the opening of the chamber 6 at positions facing the edges of the mirror holding member 13, vacuum sealing is assured. The mirror 1Y is fixed to the chamber 8 by fastening the mirror holding member 13 by fixing bolts 5. The mirror unit having the above-described configuration is disposed in the beam line between the synchrotron ring and the exposure apparatus so as to guide the radiation light to the exposure apparatus present at the downstream side while spreading the radiation light in a direction perpendicular to the sheet plane of the synchrotron radiation by the mirror 1Y. The relative position between the reflecting surface 1Ya of the mirror 1Y and the radiation light is precisely aligned by driving the entire chamber 6 by a position-adjusting mechanism (not shown). It is possible to precisely align the reflecting surface 1Ya making the back 1Yb a reference by precisely measuring the shape of the mirror 1Y before disposing the mirror 1Y in the chamber 6. The relative movement of the chamber 6 with respect to the beam line during the alignment can be absorbed by the bellows 8a and 8b. The position of the mirror 1Y changes due to the deformation of the arch portion 14 depending on whether the inside of the chamber 6 is maintained in a vacuum or exposed to the atmosphere. Accordingly, the mirror 1Y must be positioned while maintaining the inside of the chamber 6 in a vacuum. While light having longer wavelengths of the radiation light is reflected by the reflecting surface 1Ya of the mirror 1Y, light having shorter wavelengths of the radiation light is absorbed by the mirror 1Y. The energy of the absorbed light is converted into heat, which is conducted through the mirror 1Y and is radiated into the atmosphere from the back 1Yb of the mirror 1Y, which is exposed to the atmosphere. If the heat cannot be sufficiently radiated only by atmospheric cooling, a cooling-water channel may be formed in the back 1Yb or the inside of the mirror 1Y, and cooling water may be circulated therein. If the reflecting surface 1Ya of the mirror 1Y is damaged, the mirror 1Y must be exchanged. When exchanging the mirror 1Y, the connected member comprising the mirror 1Y and the mirror holding member 13 integrated by brazing is exchanged. That is, the connected member comprising the mirror 1Y and the mirror holding member 13 is first detached by removing the fixing bolts 5, the gasket 3 is then exchanged, and a new connected member comprising a mirror 1Y and a mirror holding member 13 is fixed to the chamber 6 by the fixing bolts 5. Thus, the exchange of the mirror 1X is completed. By previously providing a connected member comprising a mirror 1Y and a mirror holding member 13 for exchange, the time required for the exchange can be shortened. According to the above-described configuration, since it is only necessary to provide a space for passing incident light and reflected light within the mirror chamber, it is possible to reduce the volume of the mirror chamber and to reduce the surface area of the inside of the chamber. As a result, only a small evacuation capability is required for an evacuation system. In order to prevent the shape of the reflecting surface 1Ya of the mirror 1Y from being deformed by heat, brazing of the mirror 1Y and the mirror holding member 13 is performed before polishing the reflecting surface 1Ya. After the brazing, the surface of the mirror 1Y is polished so as to provide a cylindrical surface. Although in the above-described embodiment the mirror 1Y is fixed to the mirror holding member 13 by brazing, the mirror 1Y may be fixed to the mirror holding member 13 by any other method provided that vacuum sealing can be realized. Although in the above-described embodiment a gasket is used for performing vacuum sealing, an O-ring may also be used. FOURTH EMBODIMENT FIG. 8 is a vertical cross-sectional view of a mirror unit according to a fourth embodiment of the present invention. FIG. 9 is a cross-sectional view taken along line A--A shown in FIG. 8. FIG. 10 is a top plan view of the mirror unit shown in FIG. 8. As in the above-described first embodiment, the present embodiment relates to a mirror unit for supporting a mirror, provided in the optical path of sheet-shaped synchrotron radiation light C between a synchrotron ring, serving as a light source, and a semiconductor exposure apparatus utilizing synchrotron radiation light (not shown), for spreading the synchrotron radiation light C in a direction perpendicular to the sheet plane of the synchrotron radiation by a cylindrical reflecting surface of the mirror. The inside of the chamber for providing the optical path of the synchrotron radiation light C is maintained in a vacuum. In FIGS. 8 through 10, the same components as those shown in FIGS. 1 and 2 are indicated by the same reference numerals, and a description will be omitted for components described in the first embodiment. As shown in FIGS. 8 through 10, a reflecting surface 1Za of a mirror 1Z has the shape of a portion of a cylinder having a radius of about 100 m so as to spread a sheet-shaped light beam in a direction perpendicular to the sheet plane of the synchrotron radiation. The entirety of a back surface 1Zb, opposite to the reflecting surface 1Za, of the mirror 1Z is uniformly fixed to a mirror holding block 15, serving as a mirror holding member, by means of brazing so as to be integral with the mirror holding block 15 (see brazed portions B). The mirror holding block 15 is disposed in the opening of the chamber 6 so that the reflecting surface 1Za of the mirror 1Z is present inside the chamber 6. In order to provide the chamber 6 with airtightness, annular edges for vacuum sealing are formed on a surface of the mirror holding block 15. By compressing the gasket 3 between the above-described edges and edges formed along the opening of the chamber 6 at positions facing the edges of the mirror holding block, vacuum sealing is assured. The mirror 1Z is fixed to the chamber 6 by fastening the mirror holding block 15 by fixing bolts 5. In order to prevent the generation of a non-uniform force to deform the mirror holding block 15 and to distort the reflecting surface 1Za of the mirror 1Z when fastening the mirror holding block 15 by the fixing bolts 5, the mirror holding block 15 has a sufficient strength and includes a groove around its surface connected to the mirror 1Z. The back of the mirror holding block 15 is finished to a plane having high accuracy, and is used as a reference for the alignment of the reflecting surface 1Za of the mirror 1Z. The synchrotron radiation light is reflected by the mirror 1Z, but light having short wavelengths is absorbed by the mirror 1Z and is converted into heat. There is the possibility that the mirror 1Z is deformed by thermal expansion due to the heat. In order to cool the heat absorbed by the mirror 1Z, a (cooling) channel 16 for running cooling water is provided within the mirror holding block 15. The cooling water is guided from a cooling-water inlet 17a into the channel 16 to absorb the heat conducted from the mirror 1Z, and is discharged from a cooling-water outlet 17b. The cooling water is maintained at a constant temperature by a cooling device (not shown). The mirror unit having the above-described configuration is disposed in the beam line between the synchrotron ring and the exposure apparatus so as to guide the radiation light to the exposure apparatus present at the downstream side while spreading the radiation light in a direction perpendicular to the sheet plane of the synchrotron radiation by the mirror 1Z. The relative position between the reflecting surface 1Za of the mirror 1Z and the radiation light is precisely aligned by driving the entire chamber 6 by a position-adjusting mechanism (not shown). It is possible to precisely align the reflecting surface 1Za making the external surface of the mirror holding block 15 (the side of the mirror chamber exposed to the atmosphere) a reference by precisely measuring the shape of the mirror holding block 15, to which the mirror 1Z is bonded, before disposing the mirror 1Z in the chamber 6. The relative movement of the chamber 6 with respect to the beam line during the alignment can be absorbed by the bellows 8a and 8b. The entire chamber 6 is deformed differently due to the atmospheric pressure depending on whether the inside of the chamber 6 is maintained in a vacuum or exposed to the atmosphere. Accordingly, the mirror 1Z must be positioned while making the inside of the chamber 6 a vacuum when very precise positioning is required. If the reflecting surface 1Za of the mirror 1Z is damaged, the mirror 1Z must be exchanged. When exchanging the mirror 1Z, the connected member comprising the mirror 1Z and the mirror holding block 15 integrated by brazing is exchanged. That is, the connected member comprising the mirror 1Z and the mirror holding block 15 is first detached from the chamber 6 by removing the fixing bolts 5, cooling pipes (not shown) are then detached from the cooling-water inlet 17a and the cooling-water outlet 17b, pipes are mounted in a connected member comprising a new mirror 1Z and a new mirror holding block 15, the gasket 3 is exchanged, and the new connected member comprising the mirror 1Z and the mirror holding block 15 is fixed to the chamber 6 by the fixing bolts 5. Thus, the exchange of the mirror 1Z is completed. Since it is unnecessary to perform an operation of mounting pipes for cooling water within the mirror chamber, cooling water leaking within the chamber 6 during the mounting operation will be prevented. By previously providing a connected member comprising a mirror 1Z and a mirror holding block 15 for exchange, the time required for the exchange can be shortened. According to the above-described configuration, since it is only necessary to provide a space for passing incident light and reflected light within the mirror chamber, it is possible to reduce the volume of the mirror chamber and to reduce the surface area of the inside of the chamber. As a result, only a small evacuation capability is required for an evacuation system. In order to prevent the shape of the reflecting surface 1Za of the mirror 1Z from being deformed by heat, brazing of the mirror 1Z and the mirror holding block 15 is performed before polishing the reflecting surface 1Za. After the brazing, the surface of the mirror 1Z is polished so as to provide a cylindrical surface. Although in the above-described embodiment the mirror 1Z is fixed to the mirror holding block 15 by brazing, the mirror 1Z may be fixed to the mirror holding block 15 by any other method provided that vacuum sealing can be realized. Although in the above-described embodiment a gasket is used for performing vacuum sealing, an O-ring may also be used. Although the present invention has been described illustrating the four embodiments in which synchrotron radiation light is guided to an exposure apparatus using a mirror having a cylindrical reflecting surface while maintaining an exposure atmosphere, the present invention may, of course, be also applied to a mirror-swinging method. As described above, since heat absorbed by the reflecting surface of the mirror is conducted to the atmosphere without passing through an interface in a vacuum and is cooled, an excellent cooling efficiency is obtained. Since the mirror can be mounted in the chamber in the same manner as mounting a flange, the operability is greatly improved and the mirror can be easily exchanged as compared with the conventional approach in which an operation of mounting the mirror is performed by putting hands within the chamber through a maintenance hole of the chamber. Since no movable unit is present within the chamber and only the reflecting surface off the mirror is exposed within the chamber, the surface area of the chamber is reduced, and therefore an evacuating system having a small evacuating capability can be used. According to the above-described configuration, it is possible to provide a mirror unit having an excellent maintenance capability and a high reliability. Next, a description will be provided of a method of manufacturing devices utilizing an exposure apparatus having any of the above-described mirror units. FIG. 11 is a flowchart for manufacturing minute devices (semiconductor chips of IC's (integrated circuits), LSI's (large-scale integrated circuits) or the like, liquid-crystal panels, CCD's (charge-coupled devices), thin-film magnetic heads, micromachines or the like). In step S1 (circuit design), circuit design of the semiconductor devices is performed. In step S2 (mask manufacture), masks on which designed circuit patterns are formed are manufactured. In step S3 (wafer manufacture), wafers are manufactured using a material, such as silicon or the like. Step S4 (wafer process) is called a preprocess, in which actual circuits are formed on the wafers by means of photolithography using the above-described masks and wafers. The next step S5 (assembly) is called a postprocess which manufactures semiconductor chips using the wafers manufactured in step 54, and includes an assembling process (dicing and bonding), a packaging process (chip encapsulation), and the like. In step S6 (inspection), inspection operations, such as operation-confirming tests, durability tests and the like of the semiconductor devices manufactured in step S5, are performed. The manufacture of semiconductor devices is completed after passing through the above-described processes, and the manufactured devices are shipped (step S7). FIG. 12 is a detailed flowchart of the above-described wafer process. In step S11 (oxidation), the surface of the wafer is oxidized. In step S12 (CVD (chemical vapor deposition)), an insulating film is formed on the surface of the wafer. In step S13 (electrode formation), electrodes are formed on the surface of the wafer by vacuum deposition. In step S14 (ion implantation), ions are implanted into the wafer. In step S15 (resist process), a photosensitive material is coated on the wafer. In step S16 (exposure), the circuit pattern on the mask is exposed and printed on the wafer by the above-described exposure apparatus. In step S17 (development), the exposed wafer is developed. In step S18 (etching), portions other than the developed resist image are etched off. In step S19 (resist separation), the resist which becomes unnecessary after the completion of the etching is removed. By repeating these steps, a final circuit pattern made of multiple patterns is formed on the wafer. By using the manufacturing method of the present embodiment, it is possible to manufacture semiconductor devices with a high degree of integration which have previously been difficult to manufacture. The individual components shown in outline or designated by blocks in the drawings are all well known in the mirror unit and exposure apparatus arts and their specific construction and operation are not critical to the operation or the best mode for carrying out the invention. While the present invention has been described with respect to what is presently considered to be preferred embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. To the contrary, the present invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
061750514	abstract	Liquid metal coolants, such as alkali metal used in nuclear reactor systems can be safely deactivated to form a disposable solid waste material. The alkali metal is dissolved in an ammoniacal liquid, such as anhydrous liquid ammonia to form a reaction mixture comprising alkali metal cations and solvated electrons. A precipitating agent that ionizes in the liquid ammonia is introduced into the reaction mixture to combine with the alkali metal cations and/or solvated electrons to form a precipitating alkali metal salt. Additionally, solidified alkali metal remaining within the coolant system after initial drainage of liquid alkali metal can be dissolved by circulating an ammoniacal liquid within the coolant system. Removal of the liquid ammonia having the alkali metal dissolved therein is combined with a ionizable precipitating agent to form a alkali metal salt.
053435044	summary	BACKGROUND OF THE INVENTION Nuclear power reactors are a well known source of energy. In one type of nuclear reactor the nuclear fuel is comprised of elongated rods formed of sealed cladding tubes of suitable material, such as a zirconium alloy, containing uranium oxide and/or plutonium oxide as the nuclear fuel. A number of these fuel rods are grouped together and contained in an open-ended tubular flow channel to form a separately removable fuel assembly or bundle. A sufficient number of these fuel bundles are arranged in a matrix, approximating a right circular cylinder, to form the nuclear reactor core capable of self-sustaining a fission reaction. The core is submerged in a fluid, such as light water, which serves both as a coolant and as a neutron moderator. A typical fuel bundle is formed by an array of spaced fuel rods supported between upper and lower tie plates; the rods typically being in excess of ten feet in length, on the order of one-half inch in diameter and spaced from one another by a fraction of an inch. To provide proper coolant flow past the fuel rods it is important to maintain the rods in precisely controlled, spaced relation such as to prevent bowing and vibration during reactor operation. A plurality of fuel rod spacers are thus utilized at spaced intervals along the length of the fuel bundle for this purpose. Design considerations of such fuel rod bundle spacers include the following: retention of rod-to-rod spacing, retention of fuel bundle shape, allowance for fuel rod thermal expansion, restriction of fuel rod vibration, ease of fuel bundle assembly, minimization of contact areas between spacer and fuel rods, maintenance of structural integrity of the spacer under normal and abnormal (such as seismic) loads, minimization of reactor coolant flow distortion and restriction, maximization of thermal limits, minimization of parasitic neutron absorption, and minimization of manufacturing costs including adaptation to automated production. Commonly assigned Matzner et al. U.S. Pat. No. 4,508,679 discloses and claims a nuclear fuel rod bundle spacer uniquely constructed to address these design concerns. As disclosed therein, a spacer is formed of an array of conjoined tubular cells or ferrules surrounded by a peripheral support band, each ferrule bore thus providing a passage through which a fuel rod or other elongated element of the fuel bundle is inserted. The ferrules are spot welded together and to the peripheral support band to provide an assembly of high structural strength. The rods or elements extending through the ferrules are centered and laterally supported therein between rigid projections or stops and resilient members. The rigid projections or stops are inwardly formed as fluted or dimpled portions of the ferrule wall at locations near the upper and lower ferrule edges to maximize the axial distance therebetween and thus enhance fuel rod support. The resilient members take the form of slender continuous loop springs of generally elliptical shape held captive by oppositely directed tabs formed by C-shaped cutouts in the walls of a pair of adjacent ferrules, whereby the two sides of each spring member project into the bores of its ferrule pair. Thus, a single spring serves two ferrules in biasing the fuel rods into contact with the two axially spaced pairs of stops pursuant to centering the rods in the ferrule bores. In commonly assigned U.S. Patent Application entitled "Nuclear Fuel Bundle Spacer Spring Force Gauge", Ser. No. 07/659,664, filed Feb. 25, 1991, a gauge is disclosed for measuring the fuel rod-centering forces exerted by the two sides of the Matzner et al. double-acting springs assembled in a manufactured spacer as a quality assurance check prior to being put into nuclear reactor service. It is also desirable to determine the integrity of these springs at times of reactor servicing and/or refueling. It has been determined that the most reliable integrity check to determine whether long periods of high temperature and radiation exposure have degraded the utility of these springs is to measure their spring constant (ratio of spring force to spring deflection). SUMMARY OF THE INVENTION It is accordingly an objective of the present invention to provide a gauge suitable for quality assurance application to measure the spring constant of double-acting, fuel rod-centering springs assembled in spacers employed in nuclear fuel bundles. Additional objectives and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. To achieve the objectives and in accordance with the purpose of the invention, as embodied and described herein, the invention comprises a gauge for measuring the spring constants of double-acting springs assembled with different pairs of ferrules in a spacer of a nuclear fuel bundle, wherein each spring has a first resilient side acting in one ferrule of each ferrule pair to exert a fuel rod centering force and a second resilient side acting in the other ferrule of each pair to exert a separate fuel rod centering force. The spring constant gauge includes an alignment rod for insertion into one of the ferrules of a pair to simulate the presence of a fuel rod and thus load the first resilient side of the spring. The gauge also includes a probe for insertion into the other ferrule of the ferrule pair also to simulate the presence of a fuel rod. A force measuring device is included with the probe and is subjected to the fuel rod-centering force exerted by the second resilient side of the spring. A deflection measuring device is also provided to induce plural measured deflections of the second resilient side of the spring. The spring force readouts of the force measuring device and the spring deflection readouts of the deflection measuring device are fed to a spring constant indicating device. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as defined in the appended claims.
043552366	abstract	An adjustable strength multipole permanent magnet is disclosed that comprises a plurality of axial layers of magnetic material wherein one layer can be angularly displaced with respect to an adjacent layer, each of said axial layers comprising a plurality of segments comprising an oriented, anisotropic,, permanent magnet material arranged in a ring, each segment having a predetermined easy axis orientation that is preferably determined by the formula: EQU .alpha.=2.theta.. where .theta. is the angle between the radial symmetry line of a segment and the X-axis and .alpha. is the angle between said radial line and the easy axis of the segment.
	summary
044407149	abstract	An inertial confinement fusion method in which target pellets are imploded in sequence by laser light beams or other energy beams at an implosion site which is variable between pellet implosions along a line. The effect of the variability in position of the implosion site along a line is to distribute the radiation fluence in surrounding reactor components as a line source of radiation would do, thereby permitting the utilization of cylindrical geometry in the design of the reactor and internal components.
	abstract	A pressurized water nuclear reactor (PWR) includes a pressure vessel having a lower portion containing a nuclear reactor core comprising a fissile material and an upper portion defining an internal pressurizer volume. A condenser is secured to, and optionally supported by, the upper portion of the pressure vessel. A condenser inlet is in fluid communication with the internal pressurizer volume. A heat sink is in fluid communication with the condenser such that the condenser operates as a passive heat exchanger to condense steam from the internal pressurizer volume into condensate while rejecting heat to the heat sink. A condenser outlet connects with the pressure vessel to return condensate to the pressure vessel. A single metal forging having a first end welded to the pressure vessel and a second end welded to the condenser inlet may provide the fluid communication between the condenser inlet and the internal pressurizer volume.
048641464	summary	BACKGROUND OF THE INVENTION 1. Field of the Invention The disclosed invention generally relates to fire simulation by emittance of radiation that simulates one or more distinguishing attributes of the radiant energy produced by a fire, and more particularly, is directed to fire simulation apparatus and methods for simulation of substantially all of the key attributes of a fire which distinguish it from other sources of radiation. 2. Description of the Technology Fire simulators are used to check the operation of optical fire sensor systems which are in use in a variety of military and civil applications. The military, for example, deploys a number of such fire sensor systems in fighting vehicles to trigger fire-quenching Halon gas should the vehicle's crew compartment be subjected to an incipient fire from an armor piercing shell. Such systems are important in protecting the lives of vehicle occupants. Engine compartments in vehicles are also protected from fire by optical fire sensor systems. Aircraft "dry" bays, that is compartments not containing fuel, are protected by fire sensor systems which warn the crew of fire and may dispense fire-quenching material. Such sensing systems have many potential uses for protecting persons and equipment in closed areas from ignition and fire. Fire simulating systems are used to test the operation in the field of installed fire sensor systems as well as operation on the test bench or at the factory. Checks of fire sensor systems for proper operation precedent to use under actual conditions must of course use simulated fire stimuli in most circumstances. Open flames cannot be used generally as a test source since flammables are often present. Fire sensors are designed to avoid response to non-fire stimuli, so it is not surprising that known simulators are narrowly designed to include only the principal fire-like stimuli upon which a particular sensor to be tested operates. To test a fire sensor requires presenting it with one or more distinguishing features of a fire. The main distinguishing features of a fire are smoke, noise, light and heat. Fast-responding optical fire sensor systems respond to a fire's light and heat radiation. This radiation may roughly be divided into a region of ultraviolet and visible light, and infrared radiation. In particular, the main distinguishing attributes of the radiant energy emitted by a glowing fire have been found by investigators to be: light and heat represented by 1200 degrees to 1700 degrees Kelvin blackbody radiation from about 0.4 to 25 micrometers wavelength; carbon dioxide and water vapor spectral radiation emission in bands mainly at about 2.7 and 4.3 micrometers wavelength; ultraviolet light from about 0.20 to 0.32 micrometers wavelength; and a flickering pattern, which is a change of emitted radiation varying in time. It has been found that the energy emitted is nearly constant for flickering frequencies of 0 to 5 Hertz and then rolls off roughly as the inverse of the flickering frequency. A fire which glows yellow, such as burning wood for example, emits radiation having a characteristic blackbody shape, and the heat energy tends to dominate the light emissions. A natural gas fire which glows blue, also has characteristic blackbody radiation but the ultraviolet, CO.sub.2 and H.sub.2 O emissions tend to dominate the heat energy. Burning of different materials could be simulated by adjusting the relative amplitudes of radiation from manufactured sources of radiant energy which generate the light, heat and spectral emissions indicative of a fire. Known optical fire sensor systems sense one or at the most two of the distinguishing features of a fire in order to perform detection. As a result, known fire simulators have catered specifically to individual fire sensor system technologies. While these simulators are satisfactory for the sensor systems they are designed to test, such systems, because they simulate only one or perhaps two key characteristics, are useful only to test a sensor system that operates on those particular characteristics. A proliferation of various fire sensor system technologies has produced a need for a "universal" fire simulator which will test all of the currently deployed designs as well as systems with new technologies which are still not constructed or even conceived. Military services in particular, that have a variety of systems installed in aircraft and ground vehicles, could save time and expense by procuring one universal fire simulator with which to test and maintain all of their deployed systems. The use of a universal fire simulator obviates the need to use an actual fire to test fire sensing systems even where possible, for example, in laboratory or field test-stand evaluation. Improved safety, cleanliness and dependability would result from the use of such a simulator. A universal fire simulator would be especially useful if it were small enough to be held in the palm of one's hand, particularly while testing aircraft or vehicle-installed fire sensors. Frequently, fire sensors are installed in crowded compartments with only minimal access through hand-access holes. A universal fire simulator which closely simulates a fire is useful in testing fire sensors which are particularly subject to environments which may produce false alarms. Such a system would have the ability to simulate all of the key distinguishing attributes of a fire so the features of a fire sensor system which prevent false alarms are exercised. Protecting against false alarms is of prime concern in most fire sensor systems. When automatic dispensing of fire quenching or retardant materials is included in the application, false alarms can be disastrous because of the possible damage to equipment from such materials. Inappropriate fire alarms which prompt action by aircraft or vehicle crew members are likewise not desirable. None of the known fire simulating systems closely simulate all of the main distinguishing features of a fire or an ignition and fire, nor do they provide a basis for reducing the size of such simulating systems to a size that is usable in the restricted space and access of aircraft or vehicle compartments. Critical fire sensor systems, therefore, might not now be tested fully while installed. A practical and reliable means for closely simulating all of the key attributes of a fire, particularly in a small, portable size, would constitute a major advancement in the art of fire simulation. Users of fire sensor systems could employ such a system to test more fully and verify the operation of a variety of fire sensor systems in the field, on the test stand or on the production line. It is likely that they could do so at reduced costs and with improved results over currently known fire simulating systems. The aim of the present invention is to help accomplish this major advancement in the art. SUMMARY OF THE INVENTION The disclosed invention provides a simulation of the key distinguishing attributes of a fire, both static and dynamic. It will enable designers, constructors and users of fire sensor systems to evaluate more fully the operation of their systems and to insure reliable sensor operation if an actual fire should occur. The Universal Fire Simulator has sources for the generation and transmission of radiation in the ultraviolet, visible, and infrared spectral regions which are preadjusted to appropriate energy levels to reproduce the spectral energy distribution of a fire. A coil of heating wire, heated by an electric current, generates and transmits a blackbody-type distribution of energy. The current is set for the blackbody temperature desired, for example, 1200 to 1700 degrees Kelvin. Gaseous radiant emissions associated with a fire are generated and transmitted by heating a mixture of gases, of the types which are products of combustion, to emissive temperature. The mixture heating takes place in a sealed chamber which also serves as the reflector and housing for the blackbody heating wire. Simulation of a fire's flickering characteristic in the visible and infrared spectral region is provided by electrically modulating the heating wire with a source of random or "white" noise current, shaped by an electrical filter. A source of ultraviolet radiation, for example an ultraviolet bulb, generates and transmits energy in a spectral region of 0.2 to 0.3 micrometers wavelength. Like the blackbody, it is also driven by a modulating electric current to produce a "spike" of time-varying ultraviolet energy. A flash-tube source of radiant energy is provided to generate and transmit radiant energy having the radiation signature of an ignition flash. A discharge tube or photographer's flash bulb provides energy, predominantly in the visible and infrared spectrums, which simulates the distinguishing characteristics of an ignition flash. The discharge tube is fired by a stored source of high voltage, for example a charged capacitor or a simple "ring-up" circuit. A control circuit is used to select radiation sources which simulate: (1) fire only, by energizing the said heater wire coil and ultraviolet bulb; (2) ignition flash only, by energizing the said discharge tube (or photographer's flashbulb); or (3) fire ignited by ignition flash, by energizing the said discharge tube, heater wire coil, and ultraviolet bulb sequentially. This innovative system provides apparatus which can be compacted in size for ready transport to confined areas in which fire sensing and reacting equipment is housed for the purpose of testing such equipment with an appropriate simulation of a fire and ignition flash. This invention teaches a method of generating and transmitting radiation stimuli which has the key attributes of a fire both statically and dynamically. It is an object of this invention, therefore, to provide apparatus which closely simulates a fire which may be used, inter alia, to test fire sensing systems on the production line, in the field, or installed in vehicles, aircraft or the like. Another object of this invention is to provide apparatus which is adjustable in the field to simulate fires, explosions, or fires resulting from explosions. It is a further object of this invention to provide a method of generating radiant energy simulating key attributes of a fire or ignition in a convenient, portable and compact size that can be safely used to test fire sensing and reacting equipment in the engine or other compartments of vehicles or aircraft where the presence of flammables precludes the employment of actual fires. An appreciation of other aims and objects of the present invention and a more complete understanding of this invention may be achieved by persons skilled in the art by referring to the following description and by referring to the accompanying drawing.
055352502	summary	BACKGROUND OF THE INVENTION a) Field of the Invention The present invention is directed to a device for manipulating a bundle of synchrotron rays, in particular in irradiating apparatuses for deep X-ray lithography which contain within a vacuum chamber an object table for receiving an object to be irradiated, which object table is adjustable by means of a scanning movement relative to the synchrotron beam bundle entering the vacuum chamber via a window. b) Description of the Related Art Such irradiating devices can be used to fabricate microsystems components by means of a technique known as the LIGA process (lithography with synchrotron radiation, electroforming and plastics molding) (LIGA process, Microelectronic Engineering 4 (1986) 35-56). In this process, a resist layer is exposed directly by synchrotron radiation in the deep X-ray lithography process step by masking with an X-ray mask. To this end, the X-ray mask and the resist layer applied to the substrate are arranged on an object table which is adjustable in a scanning movement relative to the synchrotron beam bundle. The dimensions of the object table are typically approximately 100 mm in the horizontal direction and approximately 5 mm in the vertical direction. As a result of the action of radiation in the non-masked regions, the structure of the resist is changed in such a way that the exposed surfaces of the resist layer can be dissolved in a subsequent development process. Since the synchrotron beam bundle has substantially constant characteristics with respect to its dimensions and spectral properties, modifications are required for the multitude of different applications. These modifications must be carried out under vacuum conditions and may not have a disruptive influence on the exposure process itself. For example, overexposure at the reversal points of the scanning movement must be eliminated in particular. OBJECT AND SUMMARY OF THE INVENTION Therefore, a primary object of the present invention is to produce, under vacuum conditions, properties of the beam bundle which are adapted to the respective case of application for deep X-ray lithography, in particular which are adapted to the scanning regimen. In a device for manipulating a synchrotron beam bundle, in particular in irradiating apparatuses for deep X-ray lithography containing within a vacuum chamber an object table for receiving an object to be irradiated, which object table is adjustable by a scanning movement relative to the synchrotron beam bundle entering the vacuum chamber via a window, the proposed object is met according to the invention in that pairs of diaphragms which are displaceable relative to one another are provided between the object table and window adjacent to a filter chamber which is connected upstream of the vacuum chamber and contains filters which can be inserted into the synchrotron beam bundle, and the pair of diaphragms for which the direction of relative displacement of the diaphragms coincides with the scanning movement is coupled with the scanning movement. Filter changers are advantageously provided for inserting the filters into the synchrotron beam bundle, a pneumatic cylinder being fastened via stay rods to a vacuum flange which can be arranged on the filter chamber. The movement of the pneumatic cylinder is transmitted to a connecting rod by means of a rod linkage which extends into a guide bush and membrane bellows, a filter holder being fastened to the connecting rod. The filter holder can have two frame members which are provided with an elongated aperture adapted to the cross section of the synchrotron beam bundle. In an advantageous manner, one pair of diaphragms which are displaceable relative to one another forms a component part of a first beam limiting unit which limits the synchrotron beam bundle horizontally. For each of the diaphragms which are displaceable relative to one another, a guide rail is rigidly supported on a mounting plate and a spindle is rotatably supported on the mounting plate via holding elements, and a spindle nut which is fixed relative to rotation on the spindle carries one of the diaphragms. Sensors which are fastened to the mounting plate serve for positioning the diaphragms. The other pair of diaphragms which are displaceable relative to one another should form a component part of a second beam limiting unit which limits the synchrotron beam bundle vertically and in which the displacement of the diaphragms is carried out by driving members which substantially correspond to those driving the diaphragms and are fastened to the movable part of the object table. Apart from the selective spectral filtering, the device according to the invention at the same time realizes an edge limiting of the synchrotron beam bundle so as to rule out overexposure at the reversal points of the object table.
	summary
043943454	description	DESCRIPTION OF PREFERRED EMBODIMENTS The transducer apparatus described herein is constructed to be mounted on and to examine ultrasonically jet pump beams in nuclear reactors such as the beam 10 shown in FIG. 1. By way of background, the jet pump arrangement includes an inlet riser 11 which supplies pressurized driving water to a jet pump nozzle 12 through an elbow 13. The jet pump beam 10 is positioned between a pair of arms 14 extending from the inlet riser 11 and bearing against the elbow 13 to hold it in place. The jet pump beam 10, the arms 14, the elbow 13 and the inlet riser 11 are all part of the jet pump assembly 15 such as that shown in FIG. 1. Further details as to the construction and operation of such jet pumps are given in the previously mentioned U.S. Pat. Nos. 3,378,456 and 3,389,055 which are incorporated herein by reference. As FIG. 2A shows, a jet pump beam assembly 15' includes the beam 10, a beam bolt 16, a sleeve lock 17, and a weld plate 18. The beam 10 includes two ends 20, a raised central portion 21, and trunions 22. The ends 20 are supported in notches 23 of the arms 14 of the inlet riser 11. The bolt 16 includes a multisided head 25, threaded sides 26, and a butt end 27, which bears against a shoulder 30 of the elbow 13 (FIG. 1) of the jet pump assembly 15. The beam bolt 16 passes through both the sleeve lock 17 and the weld plate 18, but whereas the weld plate 18 does not inhibit the bolt 16 from turning, the sleeve lock 17 slides snugly over the multisided head 25 of the beam bolt 16, and (after the bolt 16 is tightened) is tack welded onto the weld plate 18 to prevent bolt 16 from loosening. Because the bolt 16 is threaded through an aperture 28 of the beam 10 and applies an upward force on the beam 10, any cracks in the beam 10 are typically localized at the raised central portion of the beam 10, where the bolt 16 passes through, and extends toward the trunions 22 in the sides of the beam 10. A typical pattern of such cracks 31 is illustrated in FIG. 2B in a plan view of the jet pump beam 10 (with the weld plate 18 cut away). The weld plate 18 shown in FIG. 2A is U-shaped, is suitably fixed onto the sides of the beam 10 and includes clearance bays 32 in the ends thereof for fitting around the trunions 22. The central portion of the weld plate 18 is disposed considerably above the beam 10 and allows access for the ultrasonic examination of the raised central portion 21 of the beam 10. FIG. 3 depicts a part of the apparatus for ultrasonically examining the jet pump beam 10, namely a transducer carriage 35 for positioning a plurality of ultrasonic transducers 36 near the jet pump beam 10 just described. FIG. 5 schematically shows the entire transducer apparatus including a switching mechanism or box 40, a signal generator or ultrasonic transmitter 41, receiver 42, and visual display 43--the last three of which are available commercially in a single console 44. The transducer carriage 35 fits over part of the superstructure of the jet pump beam assembly 15', as shown in FIG. 4, and suitably orients the ultrasonic transducers 36 toward the raised central portion 21 of the jet pump beam 10. The carriage 35 (FIGS. 3 and 4) comprises a central body 46 including extensions such as legs 47, wings 48, and struts 50, as well as a cavity 52 (shown in phantom), which is suitably fashioned in the underside of the central body 46 for receiving portions of the jet pump beam assembly 15', such as for example the upper parts of the beam bolt 16, sleeve lock 17, and weld plate 18. The legs 47 include recessed portions or bays 53 for cooperatively receiving the trunions 22 of the beam 10. Four transducers 36(1)-36(4), two on each side, are removably mounted in the wings 48 of the carriage 35 through cylindrical apertures of suitable diameter. Wing bolts (not shown) may conveniently removably secure the transducers 36 in the wings 48. The struts 50 between the ends of the wings 48 and the legs 47 protect the transducers 36 from damage in collisions that might occur when the carriage is lowered into the reactor vessel. The transducers 36(1)-36(4) in this embodiment are oriented downward 60.degree. from the horizontal toward the center of the jet pump beam 10. Other suitable orientations may be utilized, depending on the position of the transducers 36 relative to the center of the beam 10. The central body 46 of the transducer carriage 35 is preferably formed of aluminum, as are the wings 48 which extend outwardly from the body 46 for holding the transducers 36. Any convenient number of transducers 36 may be employed, but at least one is required and at least two are preferable. Suitably mounted at the top of the central body 46 is a coupling device 55 which permits the attachment of the carriage 35 to a pole 56 or other device for lowering the carriage 35 into the reactor vessel and remotely manuvering the carriage 35 into position on a selected jet pump beam assembly 15'. The coupling device 55 may be fixed, permitting no relative motion between the pole 56 and the carriage 35, but it is preferable for the device 55 to be in the nature of a swivel or universal joint which permits limited pivotal motion of the carriage 35. This permits the carriage 35 to be properly seated on a jet pump beam 10, even though the mounting pole 56 is not in exact alignment with the beam 10. An electrical lead 59 extends from each transducer 35(1)-36(4) toward the switching mechanism or box 40 shown in FIG. 5, which is located external to the reactor vessel. Conveniently, the switching mechanism 40 may be located in the immediate proximity of the console 44 which houses the signal generator 41, receiver 42, and the visual display 43. One example of such console 44 is the Krautkramer USIP11. Transducers suitable for use in this embodiment of the invention are manufactured by Ultran Laboratories under Part No. WS.5-2.25 MHZ. FIG. 5 shows the circuitry within the switching box 40, including a mode switch 60, four transducer switches 61(1)-61(4), four current limiting variable resistors 62, and terminals 63, leading a signal toward transducers 36(1) and 36(2). Accordingly, either transducer 36(3) and 36(4) may receive the transmitted signal and transfer it by leads 74 or 75, and 76 to receiver 42 and the visual display 43. In this mode of operation, switches 61 (1) and 61(2) are open, and one of the switches 61(3) and 61(4) is closed. The corresponding variable resistor 62 may be adjusted to enhance or reduce the signal level in the visual display 43. In the "pulse-echo" mode, switch 60 directs a signal from the ultrasonic transmitter 41 through lead 71' to terminal 64. A selected one of switches 61(1)-(4) is closed, determining which of the transducers sends and receives the signal generated by the transmitter 41. The transmitter 41 and receiver 42 are staggered in time of operation, preventing the transmitter signal from passing along the path of leads 71' and 76. In other words, the receiver 42 is "off" or disabled during the time fraction in which the transmitter sends its signal. Terminal 63 connecting leads 72 and 73 considerably simplifies the switching arrangement, avoiding possible attempts to switch non-cooperating transducers together in the "thru" mode. Since transducers 36(1) and 36(2) both send a signal when either of them sends a signal, switching to either transducer 36(3) or 36(4) provides meaningful information on the visual display 43. By suitably closing switch 60 to one of its two contacts and also closing a selected one or two of switches 61(1) through 61(4), the desired mode of operation (thru or pulse-echo) may be established. The "thru" mode is set by closing switch 60 to the upper contact shown in FIG. 5 and by additionally closing either switch 61(3) or 61(4) of the set of switches 61(1)-61(4) and keeping the remainder of the switches in the set open. The "pulse-echo" mode, on the other hand, is set by closing switch 60 to the lower contact shown in FIG. 5 and by additionally closing exclusively a selected one of switches 61(1) through 61(4). For ultrasonic examination, the carriage 35 is lowered into the reactor vessel, with the electric leads 59 streaming behind, and is straddlingly mounted on a selected beam 10. The legs 47 of the carriage 35 straddle the beam 10, as shown in FIG. 4, and the bays 53 of the legs 47 are seated on the trunions 22 of the beam 10. Furthermore, portions of the bolt head 25 and the sleeve lock 17 of the jet pump beam assembly 15' are disposed within the cavity 52 of the central body 46 of the carriage 35. So positioned, the transducers 36(1)-36(4) held in the wings 48 of the carriage 35 are properly oriented from above and toward the jet pump beam 10, and under the central portion of the U-shaped weld plate 18, to effect a proper ultrasonic examination of critical beam regions. By energizing the ultrasonic console 44 and manually selecting one or more transducers 36 for sending and receiving ultrasonic signals, actual test operation can commence. In particular, the switching mechanism 40 permits a selected one or two of the transducers to be operative either individually or in pairs. As noted above, the transducers 36(1)-36(4) are oriented from above in this embodiment in a form of examination commonly known as "critical angle surface examination." The angle of incidence of the ultrasonic signal to the horizontal upper surface of the beam is 60.degree.. In the "pitch-catch" mode, as it is often referred to, two of the transducers 36(1)-36(4) cooperate, one sending an ultrasonic signal and the other receiving it after passage along the top surface of the beam 10. Cracks in the surface of the beam inhibit a signal sent by the "pitch" transducer from substantially reaching the "catch" transducer 36. Whatever signal is received by the "catch" transducer is shown on the visual display 43 of the console 44, permitting an indication of the position and extent of a crack. In the "pulse-echo" mode of operation, the selected one of the transducers 36(1)-36(4) both sends and receives ultrasonic signals. A return signal is received only when the transmitted signal is substantially reflected from a crack. A second version of embodiment of a jet pump beam assembly 109 is shown in FIG. 6. In this version the assembly 109 includes a beam 110, a beam bolt 116, a weld plate 118, and a bolt lock 119 similar to the assembly 15' discussed above. The beam 110 includes two ends 120 and a raised central portion 121. Additionally, the beam includes a vertically directed, threaded cylindrical aperture 122 in the central raised section 121 and between the two ends 120. Furthermore, a pair of oppositely disposed trunions 123 extend from the sides of the beam 110. The bolt 116 includes a multisided head 125, a butt end 127, and a threaded midsection 128 of diameter, thread size, and pitch to mesh cooperatively with the threaded cylindrical aperture 122 of the beam 110 mentioned above. However, the weld plate 118 is flat, rather than U-shaped as in the first embodiment and it is mounted flush with the central raised portion 121 of the beam 110. A circular aperture in the weld plate 118 permits the beam bolt 116 to pass through without obstruction. The bolt lock 119 is in the form of a sleeve fitting over the multisided head 125 of the beam bolt 116. Additionally, the bolt lock 119 is tack welded onto the weld plate 118, and thereby locks the bolt 116 onto the beam 110. The beam assembly 109 is mounted in notches 23 of the arms 14 of the inlet riser 11 (shown in FIG. 1), and the butt 27 of the beam bolt 116 bears downward on a shoulder 30 of pipe elbow 13, thereby holding it in place in the jet pump assembly 15. A second version of the transducer carriage 138, particularly adapted to examine the version of the beam assembly 109 just discussed, is described immediately hereafter in conjunction with FIGS. 7 and 8. A cavity 139 in the underside of the carriage 138 fits over part of the superstructure of the jet pump beam assembly 109 just including the flat weld plate 118 (FIG. 6). Furthermore, extensions such as wings 140 of the carriage 138 extend below the raised central portion 121 of the beam 110 in order to examine the beam 110 for cracks from below. This is necessary since the flat weld plate 118 obstructs examination from above. The second version of the transducer carriage 138 includes a central body 146 from which the two wings 140 extend. Each of the wings 140 holds a pair of transducers 155 and each such wing has a recessed portion 145 for placement on the trunions 123. However, any suitable number of transducers may be mounted in the carriage 138. The carriage 138 includes a coupling device 156 mounted preferably near the center of its upperside. The coupling device 156 connects to a pole 157 or like device, for lowering the carriage 138 into the reactor vessel. The coupling device 156 may be of any suitable kind including a swivel or universal joint type device as mentioned hereinbefore in connection with coupling 55 of FIG. 3. Transducers 155 of any suitable kind are provided for transmitting and receiving ultrasonic signals. For this embodiment, an Ultran Laboratories PS.5-2.25 MHZ transducer is suggested. The wings 140 extend below the raised central portion 121 of the beam 110, as shown in FIG. 8, and each wing 140 includes a horizontal wing plate 161 having two blocks 162 suitably mounted on each wing plate. Each block 162 is formed with an internal approximately horizontal aperture for receiving and mounting a transducer 155 by insertion. Each of the transducers 155 is directed toward the region of the beam 110 most susceptible to cracking. Accordingly, the transducers 155 are specifically aimed toward the raised central portion 121 of the beam 110 at an angle of about 65.degree. from a vertical plane defined by the axis of the beam 110. Additionally, the transducers 155 are horizontally mounted about 0.1 inches below the raised central portion 121 of the beam 110. In the alternative, the transducers 155 can be tilted slightly upward from the horizontal, as for example, by 10.degree. in order to focus from below at the upper surface of the beam 110. The transducers 155 of the carriage 138 may be connected for operation in conjunction with the ultrasonic apparatus of FIG. 5 by substituting the electrical connections thereto (i.e., leads 163) for the connections to the transducers 36 therein shown. In operation, a technician lowers the transducer carriage 138 into a reactor vessel by pole 157. He maneuvers the carriage 138 into position whereby it straddlingly mounts the beam assembly 109 as shown in FIG. 8. In particular, the cavity 139 in the central body 146 sits over the head 125 of the beam bolt 116 and notches 145 in the wings 140 engage the trunions 122 in the beam 110. In this manner, the four transducers 155 in the instant embodiment are suitably positioned relative the jet pump beam 110 for ultrasonic examination. To begin examination, the signal generator 41 (FIG. 5) is energized, and the switching mechanism 40 is suitably manually set to allow the signal generator 41 to provide an electric signal to a chosen transducer 155. This signal is converted into an ultrasonic signal impinging on the side of the beam 110, which refracts from a longitudinal wave into a shear wave according to Snell's law and continues on a path without reflection until a crack 31 is met. This form of ultrasonic examination in which the ultrasonic shear wave signal travels within the body tested is known as "shear wave" examination. Depending on the arrangement selected by the switching mechanism 40, the receiver 42 can receive either an "echo" of the generated signal impinging on a crack, or the remnant of the transmitted signal. In the latter case, a second usually oppositely disposed transducer 155 must be used in cooperation with the first. As noted earlier, using two transducers 155--one to send, and one to receive--is known as the "pitch-catch" mode of operation. Once a given jet pump beam has been tested, the technician may remove the carriage to another beam and repeat the entire operation described above. Typically, the operation is repeated approximately 20 times in each reactor, once for each jet pump beam. After reference to the foregoing, modifications of this invention may occur to those skilled in the art. However, it is to be understood that this invention is not intended to be limited to the particular embodiment shown and described herein, but is intended to cover all modifications coming within the spirit and scope of the invention claimed.
042648238	description	DESCRIPTION OF THE PREFERRED EMBODIMENT Referring initially to FIG. 1 a well logging system embodying the concepts of the present invention is illustrated schematically. A well borehole 11 is lined with a steel casing 12 and filled with a borehole fluid 15. The steel casing 12 is cemented in place by a cement layer 13 and effectively seals off earth formations 14 from communication with the borehole 11 except in instances where the steel casing and cement layer are perforated for oil production. A fluid tight, hollow body member or sonde 16 is suspended in the borehole 11 by a well logging cable 17 of the usual armored cable type known in the art. The logging cable 17 communicates electrical signals to and from the sonde to surface equipment. At the surface, the well logging cable 17 passes over a sheave wheel 18 which is electrically or mechanically linked, as indicated by the dotted line 20, to a well logging recorder 19. This linkage enables measurements made by the downhole sonde 16 to be recorded as a function of borehole depth by the recorder 19. Signals from the well logging cable 17 are provided to surface data processing circuits 21 and to a control digital computer 30 which process measurement data to provide information which is supplied to the recorder 19 for recording as a function of borehole depth. Power supply 22, located at the surface, supplies power for the operation of the downhole equipment on cable 17 conductors. The control computer 30 provides digital control signals which will be described in more detail subsequently to the downhole sonde 16 to control the average neutron output thereof and the waveform of the neutron output as a function of time. In the downhole sonde 16 equipment is provided for making pulsed neutron measurements. While not shown in the schematic drawing of FIG. 1 it will be understood that appropriate power supplies in the downhole instrument convert power source 22, power supplied from the surface into the necessary operating voltages for the equipment in the downhole sonde 16. Control circuits 23, which will be described in more detail subsequently, provide control functions for a neutron generator tube 27 and a high voltage power supply 28 associated therewith and which are located near the lower end of the sonde. Neutron shielding material 29 which may consist of alternate layers of iron, paraffin, cadmium and borated foils or the like is provided to shield the neutron generator 27 from the remainder of the instrumentation within the downhole sonde 16. A gamma ray detector in the form of a scintillation crystal 24 of thallium activated sodium iodide or the like is optically coupled to a photomultiplier tube 25. This provides for detecting gamma radiation originating in the earth formations in the vicinity of the borehole and resultant from neutron bombardment by the neutron generator 27. As is well known in the art the impingement of gamma rays upon the detector crystal 24 produces light flashes therein whose intensity is proportional to the energy of the gamma ray producing the scintillation. The photomultiplier tube 25 is optically coupled to the detector crystal 24 and amplifies the light flashes produced by the detector crystal 24 and converts them to electrical voltage pulses whose amplitude is proportional to the intensity of the light flashes. These electrical signals are further amplified in an amplifier 26 and conducted into a data transmission circuit 31 where they are appropriately supplied to conventional cable driving circuits (not shown) for transmission to the data processing circuits 21 and the control computer 30 located at the surface of the earth. Control computer 30 may comprise, for example, a small general purpose digital computer such as the Model PDP-11 supplied by Digital Equipment Corporation of Cambridge, Mass. The neutron output of a neutron generator tube 27 of FIG. 1 is illustrated in FIG. 3 as a function of time. In the illustration two different intensity modulated neutron modes of operation of the neutron generator tube are contemplated. The high voltage power supply is on at all times in the system and modulated waveforms of neutrons as a function of time are produced by applying amplitude and/or frequency modulated voltages to the ion source of the neutron generator. The neutrons are produced by the neutron generator tube 27 as previously described. Voltages of a predetermined amplitude and frequency content are applied as a function of time to the ion-source of the neutron generator tube 41. In this manner the neutron output of the generator tube may be made to vary as indicated in FIG. 3. The surface control computer 30 monitors the target beam current, as will be described subsequently, and uses the value of this current to control the average value N.sub.avg of the neutron output. Moreover, by monitoring the target beam current and the count rate produced by the detector (24, 25 of FIG. 1) the surface control computer 30 can adjust the voltage waveform which is applied to the ion source of the neutron generator to vary logging programs (or waveshapes) if desired or to maintain optimum conditions of pulse width and repetition rate of pulsed (on-off) operation of the generator in a pulsed neutron logging measurement. In FIG. 3 two different wave shapes are shown for neutron output as a function of time. A first, sinusoidal, modulation is labelled PROG. 1 and a second, sawtooth waveshape, modulation is labelled PROG. 2. These waveshapes of neutron intensity as a function of time are provided by applying the appropriate control voltages to the generator tube ion source as a function of time. Both waveshapes vary about an average neutron output N.sub.avg. The control circuits to be described in more detail subsequently also control N.sub.avg by monitoring the target beam current and comparing this with a reference signal provided by the surface control computer 30 of FIG. 1. For typical well logging operations the on-time of the neutron generator tube in pulsed mode will usually not exceed a duty cycle of approximately 5-10% of its operating cycle. That is to say, the neutron generator tube will generally only be on from 5-10% of the time and the off periods will occupy approximately 90-95% of its time in a typical well logging operation. Neutron pulse durations of approximately 50 microseconds duration and repetition rates of from 100-20,000 pulses per second are typical for pulsed neutron well logging techniques. For modulated waveshapes the generator will, in general, produce continuous neutron output with intensity varying about an average value N.sub.avg as illustrated in FIG. 3. The neutron generator control system of the present invention operates to maintain the average value N.sub.avg of the neutron output at a constant or predetermined value for the duration of a well logging run. Obviously such a system cannot replace tritium in the tube which is used up in generating the neutron output. Long term deterioration of the neutron output is unavoidable in generator tubes which provide only deuterium in the replenisher. Tubes having a dueterium and tritium mixture can avoid such long term neutron output deterioration. The need for short term control of average neutron output arises from the relationship between the replenisher current and the neutron output, which is a complicated function. Very small changes in the replenisher current can cause very large changes in the neutron output. By monitoring the target current (which is related to the neutron output) and correcting the replenisher current to hold the target current constant, the neutron output may be stabilized for short term variations such as could occur during a well logging job. Alternatively, it should be noted that the neutron generator 27 could be operated continusouly as modulated as in FIG. 3 for certain types of well logs. In this instance the control system of the present invention would maintain approximately a constant average neutron output N.sub.avg from the neutron generator 27 for the duration of a well logging job. Referring now to FIG. 2 a portion of the control circuitry 23 of FIG. 1 having to do with the control of the neutron output from a neutron generator tube is illustrated in more detail, but still schematically. Point A of the circuit is connected to the low side of the target high voltage power supply (which may typically be negative 125 kilovolts). The neutron generator tube 41 target beam current (which is sampled at Point A) flows to ground through resistor R.sub.1 generating a voltage V.sub.B at Point A which is related to the neutron output of the generator tube. The sampled voltage at Point A is used to regulate the drain current I.sub.D of the VMOS power field effect transistor 45 (labelled FET1). This current is also the replenisher current of the neutron generator tube 41, and is sampled at point 47. The sampled voltage at Point A is converted to digital form by an analog to digital converter 51 and provided to the surface control computer 30. Similarly, counts from the detector 24, 25 of FIG. 1 are converted to digital form by an analog to digital converter 52 and provided to the surface control computer 30. In response to its preprogrammed logic, surface computer 30 provides digital voltage levels to a digital to analog converter 53, as a function of time, for controlling the ion source voltage of neutron generator. A digital to analog converter 50 converts the digital voltage signal from the computer 30 to analog form and establishes a reference voltage for controlling the average neutron output N.sub.avg of the generator tube 41. The magnitude of the reference voltage provided by DAC 50 is determined by the transfer characteristics of the VMOS power FET 45 and the relationship between the replenisher current I.sub.D and the neutron output of the generator tube 41. In general, the transfer characteristics will vary with each FET and generator tube. For the purpose of this description it will be assumed that the desired average neutron output is obtained when the average target beam current is 100 microamperes and the replenisher current is 3 amperes. These are typical values encountered in the operation of neutron generator tubes in well logging usage. In this case, the surface computer 30 would vary the digital voltage value supplied to DAC until the replenisher current is 3 amperes and the target current is 100 microamperes giving a reference voltage V.sub.B at Point A, of 3 volts. This voltage establishes the average operating point of the neutron generator tube 41. Operational amplifier 44 is connected as an inverting voltage gain circuit with the gain determined by the ratio R3/R.sub.2. The output voltage V.sub.G of the operational amplifier 44 is supplied to the gate of the VMOS power field effect transistor 45. This gate voltage controls the drain current I.sub.D of the field effect transistor 45 which is supplied from a 5 ampere current supply 42. This drain current is sampled at point 47 and fed back through resistor R3 to establish the operating conditions of the operational amplifier 44 as previously described. The non-inverting input of the operational amplifier 44 is connected to the voltage setting provided by surface computer 30 via DAC 50 through resistor R.sub.4. This voltage applied to the non-inverting input of the operational amplifier 44 plus the voltage developed across R.sub.1 by the target current of generator tube 41 determines the output voltage V.sub.g of the operational amplifier 44. If the average value of the neutron output N.sub.avg begins to decrease below the operating value as determined by the voltage level provided by surface control computer 30, the target beam current will decrease. This will cause the voltage V.sub.B to decrease. When V.sub.B decreases, this causes the output voltage V.sub.G of the operational amplifier 44 to increase. The increased voltage output V.sub.G of the operational amplifier 44 causes the replenisher current I.sub.D to increase. The increase in replenisher current I.sub.D tends to increase the target beam current as sampled at Point A and provided to surface computer 30. If the neutron output of the generator tube 41 begins to increase above predetermined average operating value N.sub.avg, the target beam current will increase. This causes the voltage V.sub.B across resistor R.sub.1 to increase. When V.sub.B increases, this causes the output voltage V.sub.G of the operational amplifier 44 to decrease. The decrease of V.sub.G, the gate voltage of field effect transistor 45, causes the replenisher current I.sub.D, as sampled at point 47, to be reduced. This in turn reduces the output of the neutron generator tube 41 by cooling the replenisher heater element. When the control voltage level provided by surface computer 30 goes to zero volts, the voltage applied to the non-inverting input of operational amplifier 44 goes to zero volts. When zero volts is applied to the non-inverting input of the operational amplifier 44, the voltage output of the operational amplifier is reduced sufficient to insure that the field effect transistor 45 is completely turned off. This interrupts the replenisher current I.sub.D completely and effectively reduces the output of the neutron generator tube 41 to zero. Thus surface control for turning neutron generator 41 on and off is provided. Similarly, feedback logic contained in surface computer 30 may be used to vary the waveshape of modulated neutron output waveforms from neutron generator tube 41. Count rate information from detector 24, 25 of FIG. 1 is supplied via ADC 52 to the surface computer. Preprogrammed logic responsive to this information and other well logging information supplied to surface computer 30 may be used to vary the neutron output of the generator. For example, information pertaining to the thermal neutron lifetime or thermal neutron decay time of the earth formation in the vicinity of the borehole 11 of FIG. 1 may be determined from detector 24, 25 count rates by the computer 30. This information can be used to control or vary the neutron pulse duration and repetition rates to optimize detector 24, 25 count rates statistically as a function of borehole depth via signals supplied from surface computer 30 to DAC 53. Similarly modulated neutron flux techniques for measuring the thermal neutron decay time and porosity of the formation as disclosed in the aforementioned U.S. Pat. No. 3,940,611 may be implemented via pre-programmed logic included in surface computer 30. Thus a very versatile and powerful tool for investigating nuclear properties of earth formations in the vicinity of a well borehole is provided by the present invention. The foregoing descriptions may make other alternative embodiments of the invention apparent to those skilled in the art. It is therefore the aim of the appended claims to cover all such changes and modifications as fall within the true spirit and scope of the invention.
047028785	claims	1. A device for searching and retrieving objects in a steam generator having an outer cylindrical shell, a horizontal tube sheet adjacent the lower end of said shell, a bundle of vertical tubes supported by said tube sheet, a wrapper barrel surrounding said tubes extending from the upper portion of said shell downwardly to a predetermined point above said tube sheet to form an annulus inside said shell and an opening through said shell to said annulus, said device comprising: (a) a sled adapted to be passed through said shell opening and down said annulus to said tube sheet; (b) a flexible tube connected at one end to said sled and having its other end extending out through said shell opening, said flexible tube being of sufficient length to be freely movable into and out of said shell opening to move said sled along said tube sheet; (c) a probe and a gripper associated with said sled for searching and retrieving objects; (d) adjusting means on said sled for changing the operating positions of said probe and said gripper; (e) control means outside of said shell extending through said flexible tube for operating said probe, said gripper and said adjusting means; (f) said control means comprising a probe cable attached to said probe, a gripper shaft attached to said gripper and a rotatable actuator cable connected to said adjusting means, said probe cable and said gripper shaft being slidably received within said flexible tube; and (g) said adjusting means comprising a rotatable turret mounted on said sled and said probe cable and said gripper shaft being slidably connected to said turret. a. a sled adapted to be passed through said shell opening and down through said annulus to said tube sheet; b. a flexible tube connected at one end to said sled and having its other end extending out through said shell opening, said flexible tube being of sufficient length to be freely movable into and out of said shell opening to move said sled along said tube sheet; c. a guide tube secured to said shell and extending from said shell opening down through said annulus to said tube sheet to guide said sled and said flexible tube into operating position on said tube sheet; d. a probe and a gripper mounted on said sled for searching and retrieving objects; e. a probe cable attached to said probe and a gripper shaft attached to said gripper extending through said flexible tube to operate said probe and said gripper; f. a rotatable turret mounted on said sled and slidably connected to said probe cable and said gripper shaft for controlling the operating positions of said probe and said gripper; and g. a rotatable actuator cable extending through said flexible tube and operatively connected to said turret to rotate said turret. 2. The device of claim 1 which includes a pull wire attached to said flexible tube. 3. The device of claim 1 which includes a guide tube secured to said shell at said shell opening and extending down through said annulus to said tube sheet to guide said sled and said flexible tube into operating position on said tube sheet. 4. The device of claim 3, wherein the lower end of said guide tube includes a segment parallel to said tube sheet. 5. The device of claim 3 which includes a guide plate for securing said guide tube to said shell. 6. In a nuclear reactor system having a steam generator which includes an outer cylindrical shell, a horizontal tube sheet adjacent the lower end of said shell, a bundle of vertical tubes supported by said tube sheet, a wrapper barrel surrounding said tubes extending from the upper portion of said shell downwardly to a predetermined point above said tube sheet to form an annulus inside said shell and an opening through said shell to said annulus, a device for searching and retrieving objects comprising: 7. The device of claim 8, wherein the lower end of said guide tube includes a segment parallel to said tube sheet. 8. The device of claim 8 which includes a guide plate for securing said guide tube to said shell.
	abstract	Radiation therapy systems and their components, including secondary radiation shields. At least some versions of the disclosed systems combine a radiation delivery device, a primary radiation shielding device, and a secondary shielding layer into an integrated, modular unit. This is accomplished by using a small direct beam shield capable of blocking a primary beam from a radiation delivery device. In turn, a thinner shielding layer can be used to surround the radiation delivery device and primary shielding device, enabling a single modular unit to be delivered to an installation site. In some embodiments, a bed may be disposed within the secondary shielding layer. In some embodiments, the system is configured to provide up to 4-pi (4π) steradians of radiation coverage to the bed from the radiation delivery device.
	abstract	A method for writing a master image on a substrate includes dividing the master image into a matrix of frames, each frame including an array of pixels defining a respective frame image in a respective frame position within the master image. An electron beam is scanned in a raster pattern over the substrate, while shaping the electron beam responsively to the respective frame image of each of the frames as the electron beam is scanned over the respective frame position, so that in each frame, the electron beam simultaneously writes a multiplicity of the pixels onto the substrate.
	summary
	summary
	claims	1. A source wire assembly for radiographic applications, including traversing a curved path of a radiographic projector, including:an axial core comprising a cable including a plurality of metallic strands, the axial core including a distal end and a proximal end;the distal end including a device for holding a radiographic source and the proximal end including a device for connecting to a drive apparatus; anda plurality of toroidal rings mounted on the cable, wherein a first portion of the toroidal rings are metallic shielding beads, and a second portion of the toroidal rings is at least one stainless steel spacer bead positioned to a proximal side of the metallic shielding beads. 2. The source wire assembly of claim 1 wherein the plurality of metallic strands are intertwined with each other. 3. The source wire assembly of claim 2 wherein each of the strands include a plurality of metal wires. 4. The source wire assembly of claim 3 wherein the plurality of metal wires within each strand are intertwined with each other. 5. The source wire assembly of claim 4 wherein the strands are intertwined in a configuration chosen from the group consisting of twisted, helix wound, woven and braided. 6. The source wire assembly of claim 5 wherein the metal wires are intertwined in a configuration chosen from the group consisting of twisted, helix wound, woven and braided. 7. The source wire assembly of claim 1 wherein the metallic shielding beads are comprised of tungsten. 8. The source wire assembly of claim 1 further including a coil spring wrapped around the core and engaging, on a first end, a stainless steel spacer bead and, on a second end, a housing of the device for connecting to a drive apparatus. 9. The source wire assembly of claim 8 wherein the housing further includes an enlarged lip with a diameter equal to or greater than that of the plurality of toroidal rings. 10. The source wire assembly of claim 9 wherein the stainless steel spacer bead engaged by the first end of the coil spring includes an undercut cylindrical slot radially outward from the core for receiving the first end of the coil spring. 11. The source wire assembly of claim 10 wherein the second end of the spring urges against the enlarged lip of the housing. 12. The source wire assembly of claim 11 wherein the enlarged lip of the housing surrounds a proximal end of the cable. 13. The source wire assembly of claim 12 wherein the device for holding a radiological source includes a blind aperture for engaging and securing a distal end of the cable. 14. The source wire assembly of claim 8 further including a spacer sleeve coaxially surrounding a portion of the cable, the spacer sleeve including a first end and a second end, the first end of the spacer sleeve abutting the device for holding a radiographic source and the second end of the spacer sleeve abutting a most distal metallic shielding bead. 15. The wire source assembly of claim 14 wherein the most distal metallic shielding bead has a lesser diameter than a diameter of other shielding beads. 16. The source wire assembly of claim 8 wherein the device for holding a radiological source further includes a capsule assembly for encasing a radiological source.
	abstract	In an illustrative embodiment, a pressurized water nuclear reactor (PWR) includes a pressure vessel (12, 14, 16), a nuclear reactor core (10) disposed in the pressure vessel, and a vertically oriented hollow central riser (36) disposed above the nuclear reactor core inside the pressure vessel. A once-through steam generator (OTSG) (30) disposed in the pressure vessel includes vertical tubes (32) arranged in an annular volume defined by the central riser and the pressure vessel. The OTSG further includes a fluid flow volume surrounding the vertical tubes and having a feedwater inlet (50) and a steam outlet (52). The PWR has an operating state in which feedwater injected into the fluid flow volume at the feedwater inlet is converted to steam by heat emanating from primary coolant flowing inside the tubes of the OTSG, and the steam is discharged from the fluid flow volume at the steam outlet.
	summary
	abstract	An over-etched defect in a semiconductor wafer is detected by applying an electrical field to the contacts in a first area and comparing the intensity measured with the intensity from a reference area. In one embodiment, one of the contacts in each of the first and reference areas is a gate contact in an MOS device and a second contact is either a source or drain contact. The selected charging field forward biases the pn junctions between the source and drain regions and the well in which they are formed. As a result, defects caused by gate contacts shorted to one of the source and drain contacts are visible using voltage contrast imaging techniques.
	description	This invention was made with government support under Contract No. DE-FC07-051D14636 awarded by the Department of Energy. The government has certain rights to this invention. 1. Field of the Invention This invention relates to water-cooled nuclear reactors, and more particularly to pressurized water reactors having in-core instrumentation that enter the reactor vessel through penetrations from the top of the reactor vessel and are used to monitor the neutron activities and coolant temperature within the core fuel assemblies. 2. Description of the Prior Art Many water-cooled nuclear reactors utilize a core of vertically-positioned fuel assemblies within a reactor vessel. To monitor the neutron activities and coolant temperature within the core fuel assemblies, movable in-core instrumentation, such as movable neutron detectors, conventionally enter the core from penetrations in the bottom of the vessel. In a few instances in the past leakage occurred at the penetrations at the bottom of the vessel which presented significant repair problems. Accordingly, it would be desirable to have all the in-core instrumentation access the core through penetrations from the top of the reactor vessel. Thus, it is therefore necessary to provide structure which can satisfactorily guide and protect the in-core instrumentation entering from the top of the vessel and mitigate the potential for leakage. To provide guidance and protection for the in-core instrumentation the upper core plate, which is just above the fuel assemblies, upward to the penetrations through the vessel head, the existing upper support columns are available in-between the upper core plate and the upper support assembly. What is needed is a structure which provides guidance and protection for the in-core instrumentation in the elevations between the upper support assembly and the penetrations in the vessel head. This invention provides upper mounted instrumentation columns that provide guidance and protection for the in-core instrumentation in between the upper support assembly and the penetrations in the reactor vessel head. The design of this invention provides a support system for the upper internals in-core instrumentation that does not require the addition of a substantial framework within the upper internals. The invention design also minimizes additional disassembly requirements to remove and install the upper internals guide tubes in the event maintenance of the guide tubes is required. The main body of each of the upper mounted instrumentation columns is seated at its bottom end at the top of the upper support assembly. Each upper mounted instrumentation column is attached at its upper end to the top of an adjacent upper guide tube through a bracket, for lateral support and alignment. Funnels of varying lengths, depending on the elevations of the matching reactor vessel head penetrations, extend from the top of the upper instrumentation columns to provide continued guidance and protection for the in-core instrumentation between the head penetrations and the top of the upper instrumentation columns. This structure is an economic and efficient way to provide guidance and protection for the in-core instrumentation. It also provides the least hindrance to the replacement of guide tubes should such replacement be required. Referring now to the drawings, FIG. 1 shows a simplified nuclear reactor primary system, including a generally cylindrical reactor pressure vessel 10 having a closure head 12 enclosing a nuclear core 14. A liquid reactor coolant, such as water, is pumped into the vessel 10 by pump 16 through the core 34 where heat energy is absorbed and is discharged to a heat exchanger 18, typically referred to as a steam generator, in which heat is transferred to a utilization circuit (not shown) such as a steam driven turbine-generator. The reactor coolant is then returned to the pump 16, completing the primary loop. Typically, a plurality of the above-described loops are connected to a single reactor vessel 10 by reactor coolant piping 20. A conventional reactor design is shown in more detail in FIG. 2. As previously mentioned, though not shown in FIG. 2, in a conventional pressurized water reactor design, the movable in-core neutron detectors enter the core from the bottom of the reactor through tubes that extend from penetrations in the vessel bottom to the lower core plate 36 where they mate with the instrumentation thimbles within the fuel assemblies. Furthermore, in such a traditional reactor design, the thermocouples that measure core temperature enter the upper head 12 through a single penetration and are distributed by a yoke or cable conduit, such as is shown in U.S. Pat. No. 3,827,935, to the individual support columns 48 and thereby to the various fuel assemblies. In addition to the core 14 comprised of a plurality of parallel, vertical co-extending fuel assemblies 22, for purposes of this description, the other vessel internal structures can be divided into the lower internals 24 and the upper internals 26. In conventional designs, the lower internals function to support, align and guide core components and instrumentation, as well as to direct coolant flow within the vessel. The upper internals restrain or provide a secondary restraint for the fuel assemblies 22 (only two of which are shown for simplicity), and support and guide instrumentation and components such as control rods 28. In the exemplary reactor shown in FIG. 2, coolant enters the vessel 10 through one or more inlet nozzles 30, flows downward about a core barrel 32, is turned 180° in a lower plenum 34, passes upwardly through a lower core support plate 36 upon which the assemblies 22 are seated, and through and about the assemblies. The coolant flow through the core and surrounding area 38 is typically large, in the order of 400,000 gallons per minute at a velocity of approximately 20 feet per second. The resulting pressure drop and frictional forces tend to cause the assemblies to rise, which movement is restrained by the upper internals, including a circular upper core plate 40. Coolant exiting the core 14 flows along the underside of the upper core plate 40 and upwardly through a plurality of perforations 42. The coolant then flows upwardly and radially to one or more outlet nozzles 44. The upper internals 26 can be supported from the vessel or vessel head and include an upper support assembly 46. Loads are transmitted between the upper support assembly 46 (sometimes referred to as the upper support plate) and the upper core plate 40 primarily by a plurality of support columns 48. A support column is aligned above a selected fuel assembly 22 and perforation 42 in the upper core plate 40. Rectilinearly movable control rods 28 typically including a drive shaft 50 and a spider assembly 52 of neutron poison rods are guided through the upper internals 26 and into aligned fuel assemblies 22 by control rod guide tubes 54. The guide tubes are fixedly joined to the upper support assembly 46 and connected by a split pin 56 force-fit into the fop of the upper core plate 40. The pin configuration provides for ease of guide tube assembly and replacement if ever necessary, and assures that core loads, particularly under seismic or other high-loading accident conditions, are taken primarily by the support columns 48 and not the guide tubes 54. This assists in retarding guide tube deformation under accident conditions which could detrimentally affect control rod insertion capability. In accordance with this invention, all of the instrumentation is routed through penetrations in the upper head 12. This structural modification is shown in the elevational view of the upper internals illustrated in FIG. 3. The reactor internals designed in accordance with this invention relocates the instrumentation penetrations from die bottom of the reactor vessel to the reactor vessel head 12. This upper mounted instrumentation utilizes forty-two slender in-core instrumentation assembly column extensions 90 that extend above the upper support assembly 46 towards the vessel head 12 not shown in FIG. 3. These slender columns 90 provide a guide way for the in-core neutron detectors/core exit thermocouple transducers that engage the penetrations through the reactor vessel head 12. The upper mounted instrumentation columns are respectively attached to forty-two individual upper guide tubes 88 which provide lateral support for the upper mounted instrumentation columns 90 and alignment with the penetrations in the reactor vessel head as it is lowered into position. In addition, the natural frequencies of this arrangement do not coincide with the coolant pump rotation frequencies, thus avoiding setting up a resonant vibration that could damage the upper internal components. Thus, in accordance with this invention, forty-two in-core instruments exit the pressure boundary through individual penetrations in the reactor vessel head 12, similar to the 69 control rod drive mechanism drive rods. The forty-two in-core instruments and 69 guide tubes must simultaneously enter the penetrations in the reactor vessel as it is lowered into position following refueling. The instrumentation columns are long slender tubes 90 that require a lateral support to assure alignment, with the reactor vessel head penetrations. The preferred design for the upper mounted instrumentation assembly is to attach each of the forty-two in-core instrumentation assembly column extensions 90 to an adjacent rod cluster control assembly upper guide support tube 88 which can best be seen in FIGS. 4, 5 and 6. The upper guide tube 88 is modified to include a bracket 94 which attaches the in-core instrumentation assembly column extensions 90 to the upper guide tube 88 near the top 92 of the guide tube 88. The bottom end 96 of the in-core instrumentation assembly column extensions 90 are screwed into the upper ends of the upper support columns 48. The design of this invention has a number of benefits. It takes advantage of the rigid construction of the control rod guide tubes 88 to secure the position of the top end of the instrumentation columns 90 to insure alignment with the reactor vessel head penetrations as the head is lowered onto the vessel. Secondly, it provides lateral support for the instrumentation columns 90 to insure the vibrational responses; i.e., the natural frequencies, are sufficiently removed from the coolant pump excitation frequencies to prevent resonance. Thirdly, this arrangement permits the removal of individual guide tubes, should that be necessary. The design of this invention requires a bracket 94 be welded to an upper surface 92 of the upper control rod guide tube 88. The upper mounted instrumentation column extensions 90 are connected to the peripheral end of the brackets 94 through threaded joints. The bottom 96 of the upper mounted instrumentation columns 90 are threaded into the top end of the support columns 48. There is no wear concern at the bottom 96 of the upper mounted instrumentation column extension at its interface with the support columns 48. Additionally, the major pump frequencies are avoided. FIG. 4 is a plan view of the upper internals shown in FIG. 3, taken at an elevation IV-IV and clearly shows the control rod guide members 88 to which the brackets 94 and instrumentation column extensions 90 are attached. FIG. 5 is a plan view of the upper internals shown in FIG. 6, taken along the lines V-V and provides a better view of the upper control rod guides 88 and the support columns 90 at an elevation below the upper support assembly 46. Referring back to FIG. 3, it can be appreciated that the instruments gain access to the instrument thimbles in the fuel assemblies through the reactor head, into the upper funnels 98 of the in-core instrumentation assembly column extensions 90 and down through the support columns 48 where they exit the support columns into the top opening of the instrumentation thimbles in the fuel assemblies. During refueling, the in-core instruments are withdrawn into the head and removed from the upper internals 26 before the head 12 is removed from the vessel 10. 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 die scope of the invention which is to be given the full breadth of the appended claims and any and all equivalents thereof.
	description	FIGS. 1, 2a and 2b show a fuel assembly 1 according to a first embodiment of the invention. FIG. 2a is a cross section Axe2x80x94A through the lower part of the fuel assembly in FIG. 1. FIG. 2b is a cross section Bxe2x80x94B through the upper part of the fuel assembly in FIG. 1. The fuel assembly is of boiling-water type and comprises a long tubular container, of rectangular cross section, referred to as a fuel channel 2. The fuel channel 2 is open at both ends, thus forming a through-going flow passage through which coolant flows. The fuel channel 2 is provided with a hollow support means 11 of cruciform cross section, which is secured to the four walls of the fuel channel. The support means comprises four hollow wings and a hollow enlarged cruciform centre. The support means 11 forms a vertical cruciform channel 8 through which non-boiling water flows upwards through the fuel assembly. The fuel channel 2 with support means 11 surround four vertical channel-formed parts 12a-12d, so-called sub-channels, with a substantially square cross section. Each sub-channel contains a fuel bundle comprising a plurality of parallel and spaced apart fuel rods 3a, 3b, 3c. A fuel rod comprises a number of cylindrical pellets 4 of uranium dioxide, stacked on top of each other and enclosed in a cladding tube. The fuel rods in the lower part of the fuel assembly, FIG. 2a, are arranged in a symmetrical 5xc3x975 grid in which all the fuel rod positions except one are occupied by fuel rods. The non-occupied fuel rod position is located inside the cruciform centre of the support means. The spaces between the fuel rods in positions adjacent each other are traversed by coolant and are referred to hereinafter as coolant channels 14. The coolant channels formed between four fuel rods in positions adjacent to each other have a cross section area A1. The fuel rods are of three different types, full-length straight fuel rods 3a, part-length fuel rods 3b, and full-length bent fuel rods 3c. The part-length fuel rods 3b have a height which at least corresponds to half the height of the fuel assembly, but may constitute as much as 80% of the height of the fuel assembly. That part of the fuel assembly in which the part-length fuel rods are arranged is referred to in this patent application as the lower part 10 of the fuel assembly. Each sub-bundle comprises two part-length fuel rods 3b and three bent fuel rods 3c. Part-length fuel rods are marked with a P in this figure and in the following figures. Bent fuel rods are marked with a B in this figure and in the following figures. All the fuel rods 3a, 3b, 3c in a fuel bundle are retained at the bottom by a bottom tie plate 6. The part-length fuel rods 3a, 3c in the fuel bundle are retained at the top by a top tie plate 5. The fuel rods are kept spaced apart from each other by means of spacers 7a, 7b. In the lower part 10 of the fuel assembly, the fuel rods 3a, 3b, 3c are kept in position by the spacers 7a and in the upper part of the fuel assembly the fuel rods 3a, 3c are kept in position by spacers 7b. The part-length fuel rods 3b terminate below the top tie plate 5, usually in or in the vicinity of a spacer. According to the invention, the bent fuel rods 3c are arranged in positions adjacent the part-length fuel rods 3b and are bent in a direction towards these. The bending begins at the uppermost one of the spacers 7a in the lower part of the fuel assembly and terminates at the lowermost of the spacers 7b in the upper part of the fuel assembly. Before and after the bending, the fuel rod is straight. In this embodiment, the bending takes place between two consecutive spacers, which is an advantage since it is then sufficient with two different spacer types. If the bending is to be large, however, it may be necessary to distribute the bending between several spacers. According to the invention, the bent fuel rods 3c are arranged in positions adjacent the part-length fuel rods 3b and are bent in direction towards these. The bending begins at the uppermost one of the spacers 7a in the lower part of the fuel assembly and terminates at the lowermost of the spacers 7b in the upper part of the fuel assembly. Before and after the bending, the fuel rod is straight. In this embodiment, the bending takes place between two consecutive spacers, which is an advantage since it is then sufficient with two different spacer types. If the bending is to be large, however, it may be necessary to distribute the bending between several spacers. Bending may be in the interval of 1-10 mm, preferably in the range of 2-4 mm. Also, the spacers are arranged to take up the bending forces during the bending of the fuel rods. From FIG. 2b it is clear that the grid in the upper part of the fuel assembly is no longer regular. Above the part-length fuel rods an open region 15 is formed. The bent rods 3c are bent inwards towards the open region. The coolant channels which adjoin the open region will thus have a cross-section area A2 in the upper part-of the fuel assembly which is larger than their cross-section area A1 in the lower part of the fuel assembly. The other coolant channels have a cross-section area A1 which is substantially constant in its longitudinal direction. From FIG. 2b it is clear that the grid in the upper part of the fuel assembly is no longer regular. Above the part-length fuel rods an open region 15 is formed. The ben rods 3c are bent inwards towards the open region. The coolant channels which adjoin the open region will thus have a cross-section area A2 in the upper part of the fuel assembly which is larger than their cross-section area A1 in the lower part of the fuel assembly. The other coolant channels have a cross-section area A1 which is substantially constant in its longitudinal direction. The second cross-sectional area A2 is more than 10% larger than the first cross-sectional area A1. Moreover, the second cross-sectional area A2 may be between 10% and 40% larger than the first cross-sectional area A1. FIGS. 3a and 3b show the invention applied to a different type of fuel assembly. This fuel assembly comprises two vertical water channels 16a, 16b with a substantially circular cross section. FIG. 3a shows a cross section through the lower part of the fuel assembly. The fuel rods are arranged in a symmetrical 9xc3x979 grid. The fuel assembly has eight part-length fuel rods 3b and the other fuel rods 3a, 3c are full-length rods. FIG. 3b shows a cross section through the upper part of the fuel assembly. The four fuel rods which are arranged immediately adjacent to a part-length fuel rod are bent inwards towards the open region which is formed above the part-length fuel rod. The coolant channels which adjoin the open region above the part-length fuel rod have a cross-section area A4, A6 in the upper part of the fuel assembly which is larger than the cross-section area A3, A5 in the lower part of the fuel assembly. FIGS. 4a and 4b show a further embodiment of the invention. This embodiment differs from the preceding one in that the bent fuel rods 3c have a diameter d1 which is larger than the diameter d2 of the straight, full-length fuel rods 3a. One advantage of arranging the bent rods with a larger diameter is that the distance between the fuel rods is reduced, which results in a reduced transverse flow from the adjoining coolant channels to the open region above the part-length fuel rods. In this embodiment the part-length fuel rods 3b have the same diameter d2 as the straight full-length fuel rods 3a. In another embodiment, the part-length fuel rods 3b may have the same diameter d1 as the bent fuel rods 3b. A disadvantage of also the part-length fuel rods also having a larger diameter is that a larger quantity of uranium is obtained in the lower part of the fuel assembly where the moderation is good. FIG. 5 shows in more detail a bent fuel rod 3c and the design of the spaces which surround the bent fuel rod. The bent rod is fixed to the bottom tie plate and the top tie plate and the rod is bent between two spacers 7a and 7b. The bending forces from the bent rod must be taken up by the spacers, and primarily by the two spacers 7a, 7b which are positioned nearest the bent part 20 of the rod. Most spacer types keep the rods in position by one or more fixed supports as well as by one or more resilient supports. According to the invention, the fixed support are arranged so as to absorb the greatest bending forces, that is, on the concave sides of the rod. Fixed supports 21a, 21b are mounted on one side each of the bent rod, one support 21a being arranged in the spacer 7b above the bent part 20 and the other support 21b being arranged in the spacer 7b below the bent part 20. On the opposite side of the fixed supports, resilient supports 22a, 22b are arranged.
	description	This application is a National Phase Application of PCT International Application No. PCT/JP2007/052209, which has an International filing date of Feb. 8, 2007, and which designated the United States of America. The present invention relates to an X-ray convergence element including a tubular body, for reflecting X-rays entered into the tubular body, and for converging the reflected X-rays, and to an X-ray irradiation device including the X-ray convergence element. For various purposes, such as research and development including development of materials or examination of living bodies, quality management including foreign object analyses or defect analyses, or the like, an X-ray analyzing device is utilized for irradiating X-rays onto a sample, detecting fluorescent X-rays emitted from the sample, transmitted X-rays through the sample, diffracted X-rays, or the like, and analyzing an internal composition or crystal structure of the sample. Some X-ray analyzing devices may reflect and converge X-rays irradiated from an X-ray source by an X-ray mirror to irradiate focused X-rays onto the sample. However, in the case of the X-ray analyzing device adopting an X-ray mirror, for example, in order to make a diameter of an X-ray beam irradiated to the sample approximately 1 μm, it has disadvantages that a high processing accuracy of an X-ray mirror surface is required to prevent scattering of the X-rays on the mirror surface, and that a temperature control is needed to reduce an influence of a thermal strain caused by energy of the incident X-rays onto the mirror surface. Because an X-ray tube (capillary) used for solving the disadvantages is formed of a narrow and long glass tube, the influence of the thermal strain can be reduced with an axially-symmetrical structure, and X-rays can be converged to higher density with a simple structure. As an example of the X-ray tube, an X-ray tube is proposed in which X-rays enter from one opening end of the X-ray tube, and the entered X-rays are totally reflected on an inner surface of the X-ray tube to exit the X-rays from the other opening end toward the sample to converge the X-rays onto the sample. In addition, it is known that the inner surface of the X-ray tube is formed in a rotating paraboloid or a rotating ellipsoid to further improve X-ray convergeability (refer to Japanese Patent Application Laid-Open No. 2001-85192). However, in the X-ray tube, according to Japanese Patent Application Laid-Open No. 2001-85192, because both ends of the X-ray tube are open, in order to prevent the entering X-rays from one opening end of the X-ray tube from directly exiting from the other opening end without being reflected inside the X-ray tube, a diameter of the other opening end on the exit side is needed to be reduced in size. Although the diameter of the other opening end on the exit side is reduced, the distance to converge the exiting X-rays is shortened to make it difficult to sufficiently ensure a working distance (WD) from the opening end on the exit side to a specimen (e.g., approximately 0.1 mm). Therefore, there arise problems in which a sample (specimen) with rough surface cannot be analyzed, a takeoff angle of fluorescent X-rays emitted from the sample cannot be ensured, diffraction of X-rays cannot be sufficiently analyzed, because the sample cannot be rotated or inclined. The present invention is made in view of the conditions described hereinabove, and provides an X-ray convergence element and an X-ray irradiation device including the X-ray convergence element. The X-ray convergence element includes a tubular body in which a diameter of an entrance-side opening end thereof is greater than that of the exit-side opening end, and an X-ray blocking member having a diameter that is approximately the same as the diameter of the exit-side opening end, the center of which being arranged on the center axis of the tubular body. Therefore, a working distance from the exit-side opening end to the specimen can be extended, and an analysis of the specimen with rough surface, a fluorescent X-ray analysis, and an X-ray diffraction analysis can be performed regardless of a size of the specimen. Another object of the present invention is to provide an X-ray convergence element and an X-ray irradiation device including the X-ray convergence element in which the X-ray blocking member is supported by a plurality of supporting members extending from an annular member fixed in proximity to the entrance-side opening end toward the center of the X-ray blocking member. Therefore, unnecessary X-rays can be blocked with a simple structure. Still another object of the present invention is to provide an X-ray convergence element and an X-ray irradiation device including the X-ray convergence element in which the X-ray blocking member is a plate-like body. The diameter of the X-ray blocking member being narrowed toward the X-ray entering side. Therefore, entering of unnecessary scattered X-rays can be prevented. Another object of the present invention is to provide an X-ray convergence element and an X-ray irradiation device including the X-ray convergence element in which the X-ray blocking member has an X-ray incident surface that is a part of a spherical surface. Therefore, entering of unnecessary scattered X-rays can be prevented. Another object of the present invention is to provide an X-ray convergence element and an X-ray irradiation device including the X-ray convergence element in which the X-ray blocking member forms a spherical body, and the X-ray convergence element includes a plurality of fixing members for fixing the X-ray blocking member to the tubular body between an inner surface of the tubular body and a surface of the X-ray blocking member. Therefore, the center of the X-ray blocking member can be easily arranged on the axis of the tubular body. Another object of the present invention is to provide an X-ray convergence element and an X-ray irradiation device including the X-ray convergence element in which the fixing members form spherical bodies. Therefore, the center of the X-ray blocking member can be easily arranged on the center axis of the tubular body with a simple structure. Another object of the present invention is to provide an X-ray convergence element and an X-ray irradiation device including the X-ray convergence element in which the fixing members are stick-like bodies arranged so as to be spaced from each other with a predetermined distance in the circumferential direction of the tubular body. Therefore, the center of the X-ray blocking member can be easily arranged on the center axis of the tubular body with a simple structure. Another object of the present invention is to provide an X-ray convergence element and an X-ray irradiation device including the X-ray convergence element in which the X-ray convergence element includes an X-ray transmitting sheet for fixing the X-ray blocking member to the entrance-side opening end. Therefore, unnecessary X-rays can be blocked with a simple structure, while more X-rays are converged. According to a first aspect of the invention, an X-ray convergence element includes a tubular body, X-rays entering from one side opening end thereof, the entered X-rays being reflected on an inner surface of the tubular body, and the reflected X-rays exit from the other side opening end while being converged. A diameter of the entrance-side opening end is greater than that of the exit-side opening end. The X-ray convergence element includes an X-ray blocking member having approximately the same diameter as the diameter of the exit-side opening end. The center of the X-ray blocking member is arranged on the center axis of the tubular body. According to a second aspect of the invention, the X-ray convergence element may further include an annular member fixed in proximity to the entrance-side opening end, and a plurality of supporting members extending from the annular member toward the center of the X-ray blocking member to support the X-ray blocking member. According to a third aspect of the invention, the X-ray blocking member may be a plate-like body, and a diameter of the X-ray blocking member may be narrowed toward the X-ray entering side. According to a fourth aspect of the invention, the X-ray blocking member may have an X-ray incident surface that is a part of a spherical surface. According to a fifth aspect of the invention, the X-ray blocking member may form a spherical body. The X-ray convergence element may include a plurality of fixing members for fixing the X-ray blocking member to the tubular body between an inner surface of the tubular body and a surface of the X-ray blocking member. According to a sixth aspect of the invention, the fixing members may be spherical bodies arranged so as to be spaced from each other in the circumferential direction of the tubular body. According to a seventh aspect of the invention, the fixing members may be spaced from each other with a predetermined distance in the circumferential direction of the tubular body. The fixing members may be stick-like bodies arranged approximately parallel to each other in the axial direction of the tubular body. According to an eighth aspect of the invention, the X-ray convergence element may further include an X-ray transmitting sheet for fixing the X-ray blocking member at the exit-side opening end. According to a ninth aspect of the invention, an X-ray irradiation device includes an X-ray convergence element for converging X-rays irradiated from an X-ray source, and irradiating the converged X-rays. The X-ray convergence element may be the X-ray convergence element according to any of the aspects of the invention described above. According to the first and ninth aspects of the invention, the inner surface of the tubular body may be, for example constructed to be a rotating paraboloid or a rotational ellipsoid about the center axis of the tubular body. X-rays entering into the entrance-side opening end of the tubular body parallel to the center axis are totally reflected on the inner surface of the tubular body when they are incident onto the inner surface of the tubular body at a smaller incident angle than the total reflected optimal angle. The reflected X-rays exit from the exit-side opening end so as to be converged at a focal point, which may be formed by the rotating paraboloid or rotational ellipsoid of the inner surface of the tubular body. The diameter of the entrance-side opening end of the tubular body is greater than that of the exit-side opening end. The X-ray blocking member having approximately the same diameter as the diameter of the exit-side opening end is arranged so as to have its center on the center axis of the tubular body. Therefore, the X-ray blocking member blocks the entering X-rays which may pass through the tubular body without being reflected on the inner surface of the tubular body, and, thus, it prevents the X-rays from directly exiting from the exit-side opening end. The entered X-rays which are not blocked by the X-ray blocking member are totally reflected on the inner surface of the tubular body, and exit from the exit-side opening end so as to be converged at the focal point. The diameter of the exit-side opening end of the tubular body is approximately the same as the diameter of the X-ray blocking member. Therefore, the diameter of the exit-side opening end of the tubular body is not needed to be a very small to irradiate a microscopical X-ray beam onto a specimen. Thus, the diameter of the exit-side opening end of the tubular body may be increased to extend a distance (i.e., an working distance) from the exit-side opening end to the focal point at which the X-rays are converged. According to the second and ninth aspects of the invention, the plurality of supporting members for supporting the X-ray blocking member extend from an annular member toward the center of the X-ray blocking member. The annular member is fixed in proximity to the entrance-side opening end. Therefore, the X-ray blocking member is fixed to the tubular body so that the center of the X-ray blocking member is located on the center axis of the tubular body. According to the third and ninth aspects of the invention, the X-ray blocking member is a plate-like body, and is narrowed toward the X-ray entering side. If the diameter of the X-ray blocking member is smaller than the diameter of the entrance-side opening end, X-rays entering from the entrance-side opening end may be reflected on a side surface of the X-ray blocking member in the axial direction to be unnecessary scattered X-rays. Thus, the greater a dimension in the axial direction of the X-ray blocking member is, the more the scattered X-rays are increased. By narrowing the diameter of the X-ray blocking member toward the X-ray entering side, a traveling direction of the entered X-rays can be significantly changed, and thereby preventing the unnecessary scattered X-rays reflected on the side surface from entering into the inner surface of the tubular body. According to the fourth and ninth aspects of the invention, the X-ray blocking member has an X-ray incident surface that is a part of a spherical surface to eliminate the side-surface portion parallel to the axial direction of the X-ray blocking member. Therefore, X-rays that are incident to the X-ray blocking member are prevented from entering to the inner surface of the tubular body as an unnecessary scattered X-ray. According to the fifth and ninth aspects of the invention, the X-ray blocking member forms a spherical body. A plurality of fixing members for fixing the X-ray blocking member to the tubular body are provided between the inner surface of the tubular body and the surface of the X-ray blocking member. Therefore, the center of the X-ray blocking member is easily arranged on the center axis of the tubular body. According to the sixth and ninth aspects of the invention, the fixing members are spherical bodies arranged so as to be spaced from each other with a predetermined distance in the circumferential direction of the tubular body. Therefore, if the diameters of the spherical bodies are the same, the center of the X-ray blocking member is arranged on the center axis of the tubular body. According to the seventh and ninth aspects of the invention, the fixing members are spaced from each other with a predetermined distance in the circumferential direction of the tubular body, and are stick-like bodies arranged approximately parallel to each other in the axial direction of the tubular body. Therefore, if the diameters or thicknesses of the stick-like bodies are the same, the center of the X-ray blocking member is arranged on the center axis of the tubular body. According to the eighth and ninth aspects of the invention, the X-ray transmitting sheet may be provided for fixing the X-ray blocking member at the entrance-side opening end. Therefore, unnecessary X-rays are blocked by the X-ray blocking member, while transmitting more X-rays through the X-ray transmitting sheet. According to the first and ninth aspects of the invention, the diameter of the entrance-side opening end of the tubular body is greater than that of the exit-side opening end. The X-ray blocking member having approximately the same diameter as the diameter of the exit-side opening end is provided. The center of the X-ray blocking member is arranged on the center axis of the tubular body. Therefore, the entered X-rays do not directly exit from the exit-side opening end without being totally reflected on the inner surface of the tubular body. In addition, the diameter of the exit-side opening end can be increased, and the working distance from the exit-side opening end to the specimen can be extended. By extending the working distance, the X-rays can be irradiated onto a desired position of the specimen even if the specimen has a rough surface. In addition, a sufficient takeoff angle of fluorescent X-rays emitted from the specimen can be ensured, and the specimen can be rotated at a desired angle or moved for a desired distance. Therefore, an analysis of the specimen, a fluorescent X-ray analysis, and a X-ray diffraction analysis can be performed regardless of a size of the specimen. According to the second and ninth aspects of the invention, by supporting the X-ray blocking member with a plurality of the supporting members extending from the annular member fixed in proximity to the entrance-side opening end toward the center of the X-ray blocking member, unnecessary X-rays can be blocked with a simple structure. According to the third and ninth aspects of the invention, the X-ray blocking member is the plate-like body, and the diameter of the X-ray blocking member is narrowed toward the X-ray entering side. Therefore, unnecessary scattered X-rays can be prevented from entering. According to the fourth and ninth aspects of the invention, the X-ray blocking member has the X-ray incident surface that is a part of the spherical surface. Therefore, unnecessary scattered X-rays can be prevented from entering. According to the fifth and ninth aspects of the invention, the X-ray blocking member forms a spherical body. The plurality of fixing members for fixing the X-ray blocking member to the tubular body are provided between the inner surface of the tubular body and the surface of the X-ray blocking member. Therefore, the center of the X-ray blocking member is easily arranged on the center axis of the tubular body. According to the sixth and ninth aspects of the invention, the fixing members are spherical bodies arranged so as to be spaced from each other with a predetermined distance in the circumferential direction of the tubular body. Therefore, the center of the X-ray blocking member is easily arranged on the center axis of the tubular body. According to the seventh and ninth aspects of the invention, the fixing members are spaced from each other with a predetermined distance in the circumferential direction of the tubular body, and are stick-like bodies arranged approximately parallel to each other in the axial direction of the tubular body. Therefore, the center of the X-ray blocking member is easily arranged on the canter axis of the tubular body. According to the eighth and ninth aspects of the invention, the X-ray transmitting sheet is provided for fixing the X-ray blocking member at the entrance-side opening end. Therefore, unnecessary X-rays are blocked by the X-ray blocking member with a simple structure, while transmitting more X-rays through the X-ray transmitting sheet. Hereinafter, the present invention will be described based on the appending drawings illustrating embodiments thereof. FIG. 1 is a block diagram showing a configuration of an X-ray analyzing device including an X-ray convergence element according to the present invention. In this figure, the reference numeral 1 indicates an X-ray shutter and filter for controlling ON/OFF of X-rays and an output intensity of X-rays. An X-ray convergence element 2 is attached to the X-ray shutter and filter 1. A parallel X-ray beam exiting from the X-ray shutter and filter 1 enters into the X-ray convergence element 2, the X-ray convergence element 2 totally reflects the entered X-rays on an inner surface of the X-ray convergence element 2 to converge the X-rays. Then, a diameter of the beam is narrowed by, for example 1 μm order, while leading the X-rays to an opening 15 provided in proximity to a sample stage 12. In this embodiment, the opening 15 is a space closed with an X-ray transmitting body 14, and an inside of the space is a vacuum. In this case, the vacuum space is formed in the opening 15 by sectioning the sample stage 12 and the opening 15 by the X-ray transmitting body 14. The opening 15 may be a space in atmosphere, and the entire space including the sample stage 12 may also be a vacuum space. However, it is preferable that an X-ray irradiated space is maintained to be a vacuum to prevent attenuation of secondary X-rays. In the opening 15, an exit-side opening end of the X-ray convergence element 2 is arranged. Also inside the opening 15, a tip-end portion of a fluorescent X-ray detector 8 is arranged for detecting a fluorescent X-ray emitted from a sample (specimen) 13 to which the X-rays are irradiated. In addition, a photo-receiving portion of an imaging device 11 for imaging the sample 13 placed on the sample stage 12 is provided inside the opening 15. For example, below the X-ray transmitting body 14, an annular diffracted X-ray detector 9 for detecting diffracted X-rays is arranged. On the opposite side of the sample stage 12 from where the sample 13 is arranged, a transmitted X-ray detector 10 for detecting X-rays transmitted through the sample 13. The diffracted X-ray detector 9 is not limited to the annular shape, and may also be in a shape other than the annular shape. A motor 7 is attached to the sample stage 12. The motor 7 moves the sample stage 12 in two directions that are parallel to the surface of the sample stage 12 where the sample 13 is arranged and are perpendicular to each other (X-direction and Y-direction), while rotating the X-ray irradiating direction against the sample 13 to a desired angle. The motor 7 moves the sample stage 12 in a normal direction of the surface of the sample stage 12 where the sample 13 is arranged to adjust a distance between the opening 15 and the sample stage 12. Upon analyzing the diffracted X-rays, stages that rotate about three axes R, θ, and φ (not illustrated) will be further used. A stage controller 6 is connected to the motor 7, and the stage controller 6 controls the motor 7 to control a position of the sample 13 placed on the sample stage 12. An X-ray controller 3 is connected to the X-ray shutter and filter 1, and the X-ray controller 3 performs opening/closing of the shutter and switching of the filter to control the ON/OFF of the X-rays and the output intensity of the X-rays. A data processing unit 5 is connected to the imaging device 11, the X-ray controller 3, and the stage controller 6. The data processing unit 5 transmits a control signal to the imaging device 11, the X-ray controller 3, and the stage controller 6 via a communication interface module (not illustrated) to control operations of the imaging device 11, the X-ray controller 3, and the stage controller 6, respectively. In addition, a computer 4, as well as the fluorescent X-ray detector 8, the diffracted X-ray detector 9, and the transmitted X-ray detector 10, are connected to the data processing unit 5 via the communication interface module. When the data processing unit 5 receives a control parameter of the X-ray shutter and filter 1 from the computer 4, the data processing unit 5 generates a control signal corresponding to the received parameter, and then transmits it to the X-ray controller 3. The X-ray controller 3 controls ON/OFF of the generated X-rays by the X-ray shutter and filter 1 based on the received control signal, while controlling the output intensity of the X-rays. When the data processing unit 5 receives a control parameter of the imaging device 11 from the computer 4, the data processing unit 5 generates a control signal corresponding to the received parameter, and then transmits it to the imaging device 11. The imaging device 11 captures an image of the sample 13 placed on the sample stage 12 based on the received control signal, and then transmits the captured image (including a still image) to the computer 4. When the data processing unit 5 receives a control parameter of the sample stage 12 from the computer 4, the data processing unit 5 generates a control signal corresponding to the received parameter, and then transmits it to the stage controller 6. The stage controller 6 drives the motor 7 based on the received control signal, and moves or rotates the sample stage 12. For example, the data processing unit 5 transmits the sample image captured by the imaging device 11 to the computer 4, and causes a displaying unit (not illustrated) of the computer 4 to display the captured image. When a predetermined operation button on a screen is operated, the data processing unit 5 receives the control parameter of the sample stage 12 from the computer 4. In the result, a position of the sample 13 can be controlled, while viewing the captured image of the sample 13 displayed on the displaying unit of the computer 4. The data processing unit 5 receives detection signals detected by the fluorescent X-ray detector 8, the diffracted X-ray detector 9, and the transmitted X-ray detector 10 via the communication interface module (not illustrated), and performs a predetermined data processing based on the received detection signals to output the processing results to the computer 4. The computer 4 includes a CPU, a RAM, a storage unit for storing various data, a communication unit for performing data communication with the data processing unit 5 and the like, an input/output unit, such as a mouse and a keyboard, the displaying unit, such as a display (any of units are not illustrated). The computer 4 performs a predetermined analyzing process for the sample 13 based on the output data from the data processing unit 5, and then displays the analyzing results on the displaying unit, or stores it in the storage unit (not illustrated). FIG. 2 is an exterior perspective view of the X-ray convergence element 2. The X-ray convergence element 2 includes a capillary (tubular body) 20 typically made of glass, and an X-ray blocking member 23 which will be described below. A length of the capillary 20 in the axial direction is, for example 100 mm or 200 mm. In this embodiment, an outer diameter of the capillary 20 on a side to which the X-rays enter is, for example, 5 mm, and a diameter of the entrance-side opening end 22 is approximately 1 mm. In addition, an outer diameter of the capillary 20 on a side from which the X-rays exit is, for example 4.6 mm, and a diameter of the exit-side opening end 21 is approximately 0.6 mm. FIG. 3 is a schematic view showing a longitudinal cross-section of the capillary 20. As shown in this figure, the center axis of the capillary 20 is designated as x-axis, and a radial direction of the capillary 20 is designated as y-axis. The capillary 20 is a rotational symmetry about x-axis, and an inner surface 20a of the capillary 20 forms a rotating paraboloid. A diameter φ2 of the entrance-side opening end 22 of the capillary 20 is greater than a diameter φ1 of the exit-side opening end 21 (φ2>φ1), and the disk-like X-ray blocking member 23 having the same diameter as the diameter φ1 of the exit-side opening end 21 is provided in proximity to the entrance-side opening end 22 of the capillary 20. The entering X-rays parallel to the center axis of the capillary 20 from the entrance-side opening end 22 (x-axis) are incident onto the inner surface 20a of the capillary 20 at an incident angle θ. If the incident angle θ is smaller than a total reflection optimal angle θc, the X-rays are totally reflected on the inner surface 20a of the capillary 20, and exit from the exit-side opening end 21 to be converged at a focal point F. The X-rays entering within the diameter φ1 that are centering the center axis (x-axis) are blocked by the X-ray blocking member 23. Therefore, all of the X-rays entering from the entrance-side opening end 22 are totally reflected on the inner surface 20a of the capillary 20, and exit from the exit-side opening end 21 to be converged at the focal point F (position of the sample 13). The X-rays are converged to a beam diameter of approximately 1 μm, for example. In the result, the X-rays do not directly exit from the exit-side opening end 21 without being totally reflected on the inner surface 20a of the capillary 20. Assuming that the paraboloid of the inner surface 20a of the capillary 20 is y2=4ax. A coordinate of a point P2 at the entrance-side opening end is P2(x2, y2), and a coordinate of a point P1 at the exit-side opening end is P1(x1, y1). In addition, an angle of the paraboloid at the point P1 with respect to x-axis is θ, and a coordinate of the focal point F on the paraboloid is F(a, 0). As shown in the following equations, by differentiating y2=4ax with respect to x, “a” is represented by the equation (1). Here, because y′ is represented by the equation (2), y′ can be represented by the equation (3). By substituting the equation (3) into the equation (1), “a” can be represented by the equation (4). Assuming that the length (dimension in the axial direction) of the capillary 20 is L, y2 can be represented by the equation (5). A distance S from the exit-side opening end 21 to the focal point F can be represented by the equation (6). An X-ray convergence efficiency E can be represented by the equation (7). a = 1 2 ⁢ y · y ′ ( 1 ) y ′ = ⅆ y ⅆ x ( 2 ) y ′ = tan ⁢ ⁢ θ ( 3 ) a = 1 2 ⁢ y · tan ⁢ ⁢ θ ( 4 ) y ⁢ ⁢ 2 = ( y ⁢ ⁢ 1 2 + 4 ⁢ aL ) 1 2 ( 5 ) S = x ⁢ ⁢ 1 - a ( 6 ) E = y ⁢ ⁢ 2 2 - y ⁢ ⁢ 1 2 y ⁢ ⁢ 2 2 ( 7 ) Next, the above equations will be explained by being applied with specific values. Assuming that the length L of the capillary 20 is 100 mm, the diameter of the X-ray blocking member 23 and the diameter of the exit-side opening end 21 are 0.6 mm. That is, a y-coordinate y1 at the point P1 is 0.3 mm, and the total reflected optimal angle θc is 3 mrad. In addition, the total reflected optimal angle θc may be varied in accordance with energy of X-rays and the like. In this case, the energy of X-rays is approximately 10 keV, for example. Under the conditions described above, the following values can be obtained: a=0.00045 mm from the equation (4); x1=50 mm from x1=y12/4a; y2=0.52 mm from the equation (5); S=50.0 mm that is a working distance WD from the equation (6); and the X-ray convergence efficiency E=66.7% from the equation (7). In addition, if used in a radiation light facility, and a luminance of the entered X-rays is set to 1012 photon/sec/mm2, by narrowing the diameter of the entered X-rays to 1 μm, 7×1017 photon/sec/mm2 can be realized. Alternatively, assuming that the length L of the capillary 20 is 100 mm, and the diameter of the X-ray blocking member 23 and the diameter of the exit-side opening end 21 are 0.6 mm. That is, a y-coordinate y1 at the point P1 is 0.3 mm, and the total reflected optimal angle θc is 4 mrad. In addition, the total reflected optimal angle θc may be varied in accordance with the energy of X-rays and the like. In this case, the energy of X-rays is approximately 7.5 keV, for example. Under the conditions described above, the following values can be obtained: a=0.00060 mm from the equation (4); y2=0.574 mm from the equation (5); S=37.5 mm that is the working distance WD from the equation (6), and the X-ray convergence efficiency E=72.7% from the equation (7). As described above, if X-rays with less energy are used (i.e., the total reflected optimal angle θc is greater), the working distance WD from the output point to the focal position is shorter, while the X-ray convergence efficiency is improved. On the other hand, if X-rays with greater energy are used (i.e., the total reflected optimal angle θc is smaller), the working distance WD is greater, while the X-ray convergence efficiency is degraded. These values are merely examples, and they may be arbitrarily set to obtain the desired working distance WD and X-ray convergence efficiency. In any case, the working distance WD can be sufficiently ensured, while converging the X-rays onto the sample with high efficiency. FIGS. 4A and 4B are views showing a shape of the X-ray blocking member 23. FIG. 4A shows a front view of the X-ray blocking member 23, and FIG. 4B shows a longitudinal cross-sectional view thereof. The X-ray blocking member 23 is provided with three supporting members 233 for supporting the X-ray blocking member 23 so as to extend from an annular member 232 having approximately the same diameter as the diameter of the entrance-side opening end 22 (outer diameter of the capillary 20) toward the center of the X-ray blocking member 23. The annular member 232 is fixed to the capillary 20. as follows: The annular member 232, the supporting members 233, and the X-ray blocking member 23 may be integrally formed of a metal that shields the X-rays, such as tantalum, tungsten, and molybdenum. A dimension in the axial direction (thickness) of the X-ray blocking member 23 is set to be sufficient for blocking the X-rays. It is preferable that areas of the supporting members 233 with respect to the X-ray incident surface are as small as possible so that the entering X-rays are not interrupted. In addition, in order to ensure a sufficient strength to support the X-ray blocking member 23, the supporting members 233 may be narrow stick-like shapes, and arranged so as to have 120 degrees with each other about the center axis. The number of the supporting members 233 is not limited to three, and two, or four or more members may be used. However, for the strength and the reduction of the X-ray interruption, three members may be suitable. The shape of the X-ray blocking member is not limited to that of the embodiment described above, and may be in other shapes. FIGS. 5A and 5B are views showing another shape of the X-ray blocking member. FIG. 5A shows a front view of the X-ray blocking member 24, and FIG. 5B shows a longitudinal cross-sectional view thereof. A difference from Embodiment 1 is that the diameter of the X-ray blocking member 24 is narrowed toward the X-ray entering side. The X-ray blocking member 24 is provided with three supporting members 243 for supporting the X-ray blocking member 24 so as to extend from an annular member 242 having approximately the same diameter as the diameter of the entrance-side opening end 22 (outer diameter of the capillary 20) toward the center of the X-ray blocking member 24. The annular member 242 is fixed to the capillary 20. In this case, when the entered X-rays from the entrance-side opening end 22 are reflected on a side surface of the X-ray blocking member 24 approximately in the axial direction, traveling directions of the entered X-rays are significantly changed, and thereby preventing unnecessary scattered X-rays reflected on the X-ray blocking member 24 from entering into the capillary 20. FIGS. 6A and 6B are views showing still another shape of the X-ray blocking member. FIG. 6A shows a front view of the X-ray blocking member 25, and FIG. 6B shows a longitudinal cross-sectional view thereof. A difference from Embodiment 1 is that an X-ray incident surface of the X-ray blocking member 25 forms a part of a spherical surface. The X-ray blocking member 25 is provided with three supporting members 253 for supporting the X-ray blocking member 25 so as to extend from an annular member 252 having approximately the same diameter as the diameter of the entrance-side opening end 22 (outer diameter of the capillary 20) toward the center of the X-ray blocking member 24. The annular member 252 is fixed to the capillary 20. In this case, the X-rays entering from the entrance-side opening end 22 can be blocked without being reflected on the side surface of the X-ray blocking member 25 approximately in the axial direction. Therefore, the unnecessary scattered X-rays reflected on the X-ray blocking member 25 can be prevented from entering into the capillary 20. FIGS. 7A and 7B are views showing another shape of the X-ray blocking member. FIG. 7A shows a front view of the X-ray blocking member 26, and FIG. 7B shows a longitudinal cross-sectional view thereof. A difference from Embodiment 1 is that the X-ray blocking member 26 is formed in a spherical body, and spherical fixing members 27 are used instead of the supporting members 233. The X-ray blocking member 26 is made of a metal, such as tantalum, tungsten, or molybdenum, and has the same diameter as the diameter φ1 of the exit-side opening end 21. The fixing members 27 are spherical bodies having smaller diameters than the diameter of the X-ray blocking member 26, and are arranged so as to be spaced from each other with a predetermined distance in the circumferential direction of the capillary 20. Therefore, the center of the X-ray blocking member 26 is located on the center axis of the capillary 20. Because the X-rays entering from the entrance-side opening end 22 are blocked without being reflected on the side surface of the X-ray blocking member 26 approximately in the axial direction, the unnecessary scattered X-rays reflected on the X-ray blocking member 26 are prevented from entering into the capillary 20. In addition, it is preferable that the diameters of the fixing members 27 may be as small as possible so that the entering X-rays are not interrupted. The fixing members 27 can be arranged so as to have 120 degrees from each other about the center axis. The number of the fixing members 27 is not limited to three, and, thus, two, or four or more members may also be used. The shape of the fixing member 27 is not limited to that of Embodiment 4 described above, and may be in other shape. FIGS. 8A and 8B are views showing another shape of the fixing member. Particularly, FIG. 8A shows a front view of the fixing members 28, and FIG. 8B shows a longitudinal cross-sectional view thereof. A difference from Embodiment 4 is that fixing members 28 are stick-like bodies, instead of the spherical bodies. The fixing members 28 are spaced from each other with a predetermined distance in the circumferential direction of the capillary 20, and are the stick-like bodies arranged approximately parallel to the axial direction of the capillary 20. Therefore, the center of the X-ray blocking member 26 is arranged on the center axis of the tubular body. Because the X-rays entering from the entrance-side opening end 22 are blocked without being reflected on the side surface of the X-ray blocking member 26 approximately in the axial direction, the unnecessary scattered X-rays reflected on the X-ray blocking member 26 can be prevented from entering into the capillary 20. In addition, it is preferable that a thickness of the fixing member 28 is as thin as possible so that the entering X-rays are not interrupted, and the fixing members 28 can be arranged so as to have 120 degrees from each other about the center axis. The number of the fixing members 28 is not limited to three, and, thus, two, or four or more members may also be used. A fixation method of the X-ray blocking member is not limited to those of Embodiments 1 to 5, and other fixation methods may also be used. FIGS. 9A and 9B are views showing another example of fixation of the X-ray blocking member. FIG. 9A shows a front view of the X-ray convergence element 2, and FIG. 9B shows a longitudinal cross-sectional view of the X-ray convergence element 2. In these figures, a reference numeral 30 indicates a resin film with a high X-ray transmittance (e.g., PET sheet or the like). The resin film 30 is adhered to the entrance-side opening end 22 of the capillary 20. In a central portion of the resin film 30, a half-spherical X-ray blocking member 29 having the same diameter as the diameter φ1 of the exit-side opening end 21 is fixed so as to protrude outwardly from the entrance-side opening end 22. A position of the resin film 30 may be adjusted so that the center of the X-ray blocking member 29 is easily located on the center axis of the capillary 20. In this case, by using the resin film 30 with a high X-ray transmittance, the X-rays entering from the entrance-side opening end 22 can be blocked by the X-ray blocking member 29, while necessary X-rays pass through the resin film 30. Therefore, more X-rays can be converged. In Embodiment 6 described above, the structure in which the X-ray blocking member 29 is arranged so as to protrude outwardly from the entrance-side opening end 22 with respect to the resin film 30 has been described, but it is not limited to this structure. A structure in which the X-ray blocking member 29 is arranged so as to protrude inwardly from the entrance-side opening end 22 with respect to the resin film 30 may also be applied. As explained above, according to an aspect of the present invention, the diameter φ2 of the entrance-side opening end 22 of the capillary 20 is greater than the diameter φ1 of the exit-side opening end 21. Further, the X-ray blocking member is provided so that the center thereof is arranged on the center axis of the capillary 20, and the X-ray blocking member has the same diameter as the diameter φ1 of the exit-side opening end 21, with respect to the center axis. Therefore, the incoming X-rays do not directly leave from the exit-side opening end 21 without being reflected on the inner surface of the capillary 20. Thus, the diameter φ1 of the exit-side opening end 21 can be increased, and the working distance from the exit-side opening end 21 to the sample 13 can be extended. In the result, the X-ray convergence element that can converge X-rays with high efficiency can be realized with a simple structure. In addition, by extending the working distance of the X-ray convergence element, X-rays can be irradiated at a desired position of the sample even if the sample has a rough surface. Thus, a sufficient takeoff angle of the fluorescent X-rays emitted from the sample can be ensured. Further, the sample can be rotated by a desired angle or moved for a desired distance. Therefore, An X-ray analyzing device that can perform an analysis of the sample, the fluorescent X-ray analysis, and the X-ray diffraction analysis can be realized regardless of a size of the sample. In Embodiment described above, although the structure in which the X-ray blocking member is arranged in proximity to the entrance-side opening end 22 has been described, the position of the X-ray blocking member on the axis of the capillary is not limited to this structure. The X-ray blocking member may be arranged between an X-ray source and the capillary, and may also be in any position inside the capillary. For example, the capillary may be divided into two pieces at an intermediate portion, the X-ray blocking member may be provided in proximity to an opening end of one piece of the capillary, and the divided pieces of the capillary may be fixed. In Embodiment described above, the structure in which the X-rays parallel to the axis of the capillary 20 enter from the entrance-side opening end 22 of the capillary 20 to converge the X-rays has been described. However, the inner surface of the capillary may be formed in a rotating paraboloid or a rotating ellipsoid, and an X-ray source of a point source is located at one focal position. Thus, incoming X-rays from the X-ray source are totally reflected on the inner surface of the capillary to be parallel X-rays, and the parallel X-rays are again totally reflected on the inner surface of the capillary to be converged at the other focal position. In addition, the X-ray blocking member having approximately the same diameter as that of the entrance-side opening end is arranged inside the capillary, and X-rays directly passing through from the entrance-side opening end to the exit-side opening end are blocked. In Embodiment described above, although the example in which the X-ray convergence element 2 is adopted for the X-ray analyzing device has been described, application of the X-ray convergence element is not limited to this example. For example, it may be applied to a photoelectron microscope in which a converged X-ray beam is irradiated onto a sample, and photoelectrons emitted from the sample are measured. In this case, because the X-ray beam can be converged at the microscopical focal point with high efficiency, an X-ray density can be increased, and a real-time observation of the sample can be performed at a higher rate compared to a conventional observation method. In addition, other than the above applications, the X-ray convergence element may be applied to an X-ray irradiation device for irradiating X-rays, such as an X-ray lithography, a device for causing a chemical reaction by using X-rays, and an irradiating-side lens of an X-ray microscope.
	abstract	A debris trap catches debris falling through a fuel bundle orifice in a nuclear reactor. The debris trap includes a shaft and a debris capture tray attached to an end of the shaft. The debris capture tray includes a tray cavity sized larger than the fuel bundle orifice.
	abstract	The present invention comprises a radiation blocking clothing material utilized to construct articles of clothing such as but not limited to undergarments. The radiation blocking clothing material includes a first thread fiber, a second thread fiber and a third thread fiber constructed in a double sided knit structure. The double-sided knit structure promotes the material of the first thread fiber and second thread fiber to be on one side of the body of the radiation blocking clothing. The first thread fiber is a 84 D DTY silver fiber and the second thread fiber is a 90D DTY silver thread fiber and the conductive silver functions to block radiation having Faraday properties. The third thread fiber is manufactured from a cotton or a cotton blend. The composition of the body is operable to include a range of silver content within the range of 48 to 62 percent.
	description	This is a National Stage application of PCT international application PCT/EP2016/074990, filed on Oct. 18, 2016 which claims the priority of French Patent Application No. 1560047, filed Oct. 21, 2015, both of which are incorporated herein by reference in their entirety. The invention relates to the field concerning the processing of spent nuclear fuels. More specifically, the invention relates to the use of hydroxyiminoalkanoic acids as anti-nitrous agents in reductive stripping operations of plutonium. The invention can be applied to any method for processing spent nuclear fuels that includes one or more reductive stripping operations of plutonium. Said operations are notably included in the PUREX method such as implemented in modern nuclear fuel processing plants (i.e. UP3 and UP2-800 plants in La Hague in France, and the Rokkasho plant in Japan) first to perform the U/Pu partitioning step of the first decontamination cycle of this method, and secondly to improve the plutonium decontamination of fission products in the plutonium purification cycle conventionally called «second plutonium cycle», following after this first decontamination cycle. They are also included in a certain number of methods derived from this PUREX method, such as described for example in international application PCT WO 2006/072729 [1], known under the name COEX method, or the one described in international application PCT WO 2011/000844 [2]. In the reductive stripping operations of plutonium that are implemented in the aforementioned methods for processing spent nuclear fuel, the plutonium is caused to pass from an organic phase (or solvent phase), in which it is at oxidation state IV, into an aqueous phase by reducing it to oxidation state III, a state in which its affinity for the organic phase is very low. The reduction of plutonium(IV) to plutonium(III) is induced by a reducing agent that is added to the aqueous phase used for stripping and is stabilised with an anti-nitrous agent. For the first decontamination cycle, for example of the PUREX method such as implemented in modern nuclear fuel reprocessing plants (that will more simply be called «PUREX method» in the remainder hereof), the reducing agent used to strip plutonium at the U/Pu partitioning step is uranium(IV) (or uranous nitrate), whilst the anti-nitrous agent is hydrazinium nitrate, also known as hydrazine. The main chemical reactions to be taken into consideration are: the reducing of plutonium(IV) to plutonium(III) by uranium(IV) (functional reaction):U4++2Pu4++2H2O→UO22++2Pu3++4H+ the reoxidation of plutonium(III) to plutonium(IV) (parasitic reaction):Pu3++HNO2+1,5H++0,5NO3−→Pu4++0,5H2O+1,5HNO2 the destruction of nitrous acid to azothydric acid by hydrazine (useful reaction):N2H5NO3+HNO2→N3H+HNO3+2H2O. The two first reactions take place in the aqueous and organic phases, while the nitrous acid destruction reaction by hydrazine only takes place in the aqueous phase due to the inextractability of hydrazine by the organic phase, this phase being composed of tri-n-butyl phosphate (or TBP) at 30% (v/v) in hydrogenated tetrapropylene (or HTP). The presence of plutonium(III) in the organic phase, even in small amount, catalyses oxidation of uranium(IV) via the two first reactions and thereby generates nitrous acid. It was able to be ascertained, when conducting experimental studies in laboratory centrifuge extractors, that even with short extractor residence times (in the order of a few seconds), the consumption of uranium(IV) via oxidation is very high. This oxidation of uranium(IV) is essentially developed in the organic phase, since hydrazine is only contained in the aqueous phase. As a result, reductive stripping operating schemes of plutonium provide for a large excess of reducing agent. The azothydric acid formed by the destruction reaction of nitrous acid by hydrazine reacts in turn with nitrous acid according to the reaction:HN3+HNO2→N2+N2O+H2O. The kinetics of this reaction are much slower however than the destruction of nitrous acid by hydrazine, which means that azothydric acid is found in the effluent aqueous and organic phases of the U/Pu partitioning step. Therefore, since hydrazine is not extractable by the organic phase and therefore only acts in the aqueous phase, this leads to a high consumption of reagents and to the production of chemical species that impede the industrial application of the method. To solve this problem, it was proposed in international application PCT WO 2008/148863 [3] to use a two-phase anti-nitrous system associating butanal oxime, also called butyraldehyde oxime or butyraldoxime, with hydrazine, the butanal oxime allowing the organic phase to be stabilised while hydrazine stabilises the aqueous phase. While the use of butanal oxime, in association with hydrazine, affords a certain number of advantages, in particular in that it allows a notable reduction in the quantities of uranous nitrate and hydrazine needed to perform a reductive stripping of plutonium and thereby lessening the disadvantages related to the non-extraction of hydrazine in organic phase, it is not fully satisfactory however due to: the relatively low extraction of butanal oxime by the organic phase, necessitating large quantities of this oxime to be added to the extractor in which the reductive stripping of plutonium takes place, if it is desired to obtain an efficient concentration of butanal oxime in the organic phase; in particular, at the U/Pu partitioning step, the extraction of butanal oxime by the organic phase is greatly diminished by the saturation of this phase with actinides, which finally makes the use of this oxime little adapted for the performing of this partitioning step; the continued use of hydrazine in the aqueous phase; indeed, despite the fact that hydrazine is one of the most efficient anti-nitrous agents in aqueous phase, the use thereof is restrictive not only because of the problems previously indicated relating to the formation of azothydric acid, but also on account of its toxicity: hydrazine is effectively on the list of CMR substances, i.e. substances considered by Regulation (EC) 1907/2006 for the Registration, Evaluation, Authorisation and Restriction of Chemical products (REACH Regulation) as being potentially or proven to be cancerogenic, mutagenic and/or toxic for reproduction, and it is likely to be entered sooner or later into the list of substances subject to authorisation under Annex XIV of this Regulation, in which case the marketing and industrial use thereof will be prohibited unless specific exemption is given by the European Chemicals Agency (ECHA). In addition, a reaction of butanal oxime with hydrazine, leading to the formation of a hydrazone, has been observed. This reaction reduces the performance of butanal oxime and leads to an over-consumption of these two reagents. Having regard to the foregoing, the inventors have therefore set out to find compounds having high anti-nitrous properties but the use of which is free of the disadvantages brought by the use of hydrazine such as currently used in the PUREX method, or by the use of a two-phase butanal oxime/hydrazine system such as proposed in reference [3]. More specifically, they set themselves the objective that these compounds should be more extractable than hydrazine by an organic phase, in particular of the type used in the PUREX method (under the same conditions of temperature and pressure), including when this organic phase is saturated with actinides, so that it is possible (1) to reduce the quantities of these compounds needed for a reductive stripping of plutonium and (2) to use these compounds for a stripping of plutonium at the U/Pu partitioning step in the first decontamination cycle of the PU REX method as well as for a stripping of plutonium in the second plutonium cycle of this method. They further set themselves the objective that these compounds should allow the use of hydrazine to be fully circumvented. These objectives and others are reached with the invention that proposes using at least one hydroxyiminoalkanoic acid having at least 4 carbon atoms as anti-nitrous agent in a reductive stripping operation of plutonium. It is recalled that the hydroxyiminoalkanoic acids are compounds meeting the general formula: O═C(OH)—(R)—CH═N—OH wherein R is an alkylene group having at least one carbon atom, this group possibly being straight-chain or branched when it comprises two or more carbon atoms. In the present invention, any hydroxyiminoalkanoic acid may be suitable provided that the number of carbon atoms contained in the alkylene group represented by R is at least equal to 2. However, it is preferred that the hydroxyiminoalkanoic acid should meet the above general formula wherein R is an alkylene group having 2 to 12 carbon atoms. Further, it is preferred that the hydroxyiminoalkanoic acid should meet the above general formula wherein R is a straight-chain alkylene group having 3 to 8 carbon atoms. Such hydroxyiminoalkanoic acids are: 5-hydroxyiminopentanoic acid of formula: O═C(OH)—(CH2)3—CH═N—OH; 6-hydroxyiminohexanoic acid of formula: O═C(OH)—(CH2)4—CH═N—OH; 7-hydroxyiminoheptanoic acid of formula: O═C(OH)—(CH2)5—CH═N—OH; 8-hydroxyiminooctanoic acid of formula: O═C(OH)—(CH2)6—CH═N—OH; 9-hydroxyiminononanoic acid of formula: O═C(OH)—(CH2)7—CH═N—OH; and 10-hydroxyiminodecanoic acid of formula: O═C(OH)—(CH2)8—CH═N—OH. Among these, particular preference is given to 6-hydroxyiminohexanoic acid and 8-hydroxyiminooctanoic acid. Conforming to the invention, the operation for reductive stripping of plutonium preferably comprises: contacting an organic, non-water-miscible phase comprising an extracting agent and plutonium at oxidation state IV in an organic diluent, with an aqueous phase comprising a reducing agent capable of reducing plutonium(IV) to plutonium(III) and nitric acid, one of the organic and aqueous phases additionally comprising the hydroxyiminoalkanoic acid; then separating the so contacted organic and aqueous phases. In the invention, the reducing agent contained in the aqueous phase is preferably selected from among uranium(IV), hydroxylammonium nitrate also called hydroxylamine nitrate, alkylated derivatives of hydroxylamine, ferrous sulfamate and sulfamic acid. Among these reducing agents, uranium(IV) and hydroxylammonium nitrate are particularly preferred, these being the two agents used to reduce plutonium(IV) to plutonium(III) in the PUREX method, the first at the U/Pu partitioning step of the first decontamination cycle, the second at the second plutonium cycle. Also, the extracting agent is preferably a tri-n-alkyl phosphate and better still TBP, whilst the organic diluent is preferably a straight-chain or branched dodecane, such as n-dodecane or HTP, an isoparaffinic solvent such as Isane IP185, Isane IP165 or Isopar L, or kerosene, in which case the extracting agent is preferably contained in a proportion of 30% (v/v) in this organic diluent. Whichever the case, the hydroxyiminoalkanoic acid is used at a concentration preferably ranging from 0.01 mol/L to 3 mol/L and, better still, from 0.03 mol/L to 0.5 mol/L of organic or aqueous phase, whilst the reducing agent is used at a concentration preferably ranging from 0.02 mol/L to 0.6 mol/L and, better still, from 0.05 mol/L to 0.4 mol/L of aqueous phase. Regarding the nitric acid, this is advantageously contained in the aqueous phase at a concentration ranging from 0.05 mol/L to 2 mol/L. According to one particularly preferred provision of the invention, the reductive stripping of plutonium is preferably one of the plutonium stripping operations of the PUREX method or COEX method. The hydroxyiminoalkanoic acids useful in the invention can be obtained with synthesis methods known in the state of the prior art. For example, they can particularly be obtained via: nitrosation/hydrolysis of the corresponding cycloalkanones, for example such as described in French patent 1 349 281 [4] and by Ishigaki et al. (Bull. Chem. Soc. Jap., 1977, 50(3), 726-730 [5]); or else reaction of hydroxylamine on the corresponding oxoalkanoic acids, for example as described by Ayorinde et al. (J. Am. Oil Chem. Soc., 1997, 74(5), 531-538, [6]) and by Jackman et al. (J. Org. Chem., 1982, 47(10), 1824-1831, [7]), the oxoalkanoic acids themselves possibly being obtained: either by treatment of the corresponding bromoalkanoic acids with potassium hydroxide, for example as described by Thiele et al. (ACS Chem. Biol., 2012, 7(12), 2004-2011, [8]), followed by controlled oxidation of the hydroxyalkanoic acids resulting from this treatment, for example as described by Panzer et al. (US patent application 2008/0306153, [9]) and by Rajabi et al. (Synth. Comm., 2014, 44(8), 1149-1154, [10]); or via microwave irradiation of the corresponding 2-halogenocycloalkanones, for example as described by Utsukihara et al. (Tet. Lett., 2006, 47(52), 9359-9364, [11]), followed by oxidization by sodium periodate of the 2-hydroxy-cycloalkanones resulting from this irradiation, for example as described by Carrera et al. (Tet. Lett., 2009, 50(38), 5399-5402, [12]); or further, in the case of 6-oxohexanoic acid, via oxidation by sodium periodate of 2-hydroxycyclohexanone in its dimer form, for example as described by Bouet et al. (Tet. Asym., 2008, 19(20), 2396-2401, [13]). The invention affords numerous advantages. Indeed, it offers a range of anti-nitrous agents that are capable of most efficiently blocking the reoxidation of plutonium(III) to plutonium(IV) both in aqueous phase and in organic phase, as well as blocking the oxidation of a reducing agent, such as uranium(IV), by nitrous acid. Therefore, in addition to the fact that the invention allows reductive stripping operations of plutonium to be carried out without the use of hydrazine, whether for an operation such as the one implemented at the U/Pu partitioning step of the PUREX method or an operation such as the one implemented at the second plutonium cycle of this same method, it also allows a very strong reduction in the quantities of reducing agent and anti-nitrous agent needed to perform these operations compared with the quantities required when the anti-nitrous agent is hydrazine. The invention therefore allows the envisaging of a reduction in the number of points required for adding these anti-nitrous agents to equipment dedicated to reductive stripping operations of plutonium, and hence a simplification of this equipment. In addition, due to the presence of a carboxylic acid function in the molecules of hydroxyiminoalkanoic acids, the management of these anti-nitrous agents downstream of a reductive stripping operation of plutonium is simple since they are easily solubilised in a basic aqueous phase of the type used to process the organic phase derived from the stripping of uranium(VI) for recycling thereof in a typical scheme of the PUREX method. Other characteristics and other advantages of the invention will become better apparent on reading the following examples. Evidently, these examples are only given as illustrations of the subject of the invention and are not in any manner limiting in respect thereof. 6-hydroxyiminohexanoic acid (also called «6-HIHA» in the remainder hereof) is synthesised applying the following reaction scheme: where 2-hydroxycyclohexanone, denoted 1, commercially available in its dimer form (Sigma-Aldrich), is oxidized by sodium periodate (1.5 eq.) in a mixture of tetrahydrofuran and water, to give 6-oxohexanoic acid, denoted 2, with near-quantitative yield (98%); after dissolution in ethanol, the oxoacid 2 is reacted with hydroxylamine hydrochloride (8 eq.) in an aqueous medium and in the presence of sodium hydroxide (40° C., 1 hour), to give 6-HIHA with a yield of 60%. The global yield over the two steps is 58%. 8-hydroxyiminooctanoic acid (also called «8-HIOA» in the remainder hereof) is synthesised applying the following reaction scheme: where 8-bromooctanoic acid, denoted 1′, commercially available (Sigma-Aldrich), is treated with potassium hydroxide (2.7 eq.) in a mixture of tetrahydrofuran and water under microwave irradiation (80° C., 90 W, 5 hours), to give 8-hydroxyoctanoic acid, denoted 2′, with a yield of 76%; the hydroxyacid 2′ is subjected to a controlled oxidation with 2-iodobenzoic acid (IBX, 1.5 eq.) in dimethylsulfoxide (ambient temperature, 4 hours) to give 8-oxooctanoic acid, denoted 3′, with a yield of 73%; after dissolution in ethanol, the oxoacid 3′ is reacted with hydroxylamine hydrochloride (8 eq.), in the presence of sodium hydroxide and in an aqueous medium (65° C., overnight), to give 8-HIOA with a yield of 78%. The global yield of the three steps is 43%. 2.1—Coefficients of Distribution The coefficients of distribution, denoted D, of 6-HIHA and 8-HIOA are determined at an acidity close to 0.9 mol/L, this acidity representing the acidities at which most of the plutonium contained in the extractors dedicated to reductive stripping operations of plutonium is placed in the PUREX method. For doing that, extraction tests were performed using: two organic phases comprising 30% (v/v) of TBP in HTP, in the first of which 6-HIHA was solubilised in a proportion of 0.05 mol/L, and in the second of which 8-HIOA was solubilised in a proportion of 0.01 mol/L; and two aqueous phases corresponding to two aliquots of one same aqueous solution of nitric acid at 1 mol/L. Each of the organic phases was contacted with one of the two aqueous phases for 5 minutes, under agitation and at ambient temperature (22-25° C.), with an O/A (organic/aqueous) volume ratio of 1.3, after which the contacted phases were separated from one another. The concentrations of 6-HIHA and 8-HIOA were measured in the aqueous phases (by high performance liquid chromatography) and in the organic phases (by gas phase chromatography) and the concentration of nitric acid was measured in the aqueous phases (by potentiometric titration with 0.1 M NaOH). The same test was performed using an organic phase only comprising TBP (30%, v/v) in HTP and an aqueous phase comprising 1 mol/L nitric acid and 13 g/L of uranium(IV) (previously assayed by visible spectrophotometry, λ=647 nm). After separating the organic and aqueous phases, the concentration of uranium(IV) was measured in each of these phases (by visible spectrophotometry) as well as the concentration of nitric acid in the aqueous phase (by potentiometric titration). The final acidity of all the aqueous phases was 0.9 mol/L of nitric acid. FIG. 1 shows the quantities expressed in percentages of 6-NINA, 8-HIOA and uranium(IV) respectively found in the organic and aqueous phases. This Figure, by way of indication, also shows the quantities of hydrazine found in organic phase and aqueous phase in a test conducted under similar conditions but using an organic phase only comprising TBP (30%, v/v) in HTP, an aqueous phase comprising 1 mol/L of nitric acid and 0.26 mol/L of hydrazine, in an O/A volume ratio of 2. Taking into consideration the O/A volume ratio used for each test, the following coefficients of distribution were obtained: D6-HIHA=0.43; D8-HIOA=0.45; DU(IV)=0.80; and DHydrazine=0. To allow a stabilisation of uranium(IV) both in the organic phase and in the aqueous phase, an anti-nitrous agent, irrespective of the phase in which it is initially contained, should be distributed between the organic and aqueous phases in the same manner as uranium(IV). Yet, as shown in FIG. 1 and by the coefficients of distribution indicated above, 6-HIHA and 8-HIDA are properly distributed between the organic phase and aqueous phase, which is not the case for hydrazine which is not TBP-extractable. The «protective» effect of the hydroxyiminoalkanoic acids against oxidation of uranium(IV) by nitrous acid is therefore more advantageous than that provided by hydrazine which, because it remains in aqueous phase, is not capable of destroying the nitrous acid that is likely to oxidize uranium(IV) in the organic phase. 2.2—Stabilisation of the Actinides by 6-Hydroxyiminohexanoic and 8-Hydroxyiminooctanoic Acids To verify the capability of 6-HIHA and 8-HIOA to stabilise uranium(IV) and plutonium(III) under chemical conditions close to those in which the reductive stripping of plutonium is conducted in the PUREX method, three reductive stripping tests of plutonium(IV) were carried out starting with four different organic phases, namely: a first organic phase comprising 30% (v/v) of TBP in HTP and 10 g/L of plutonium(IV), this plutonium having been previously extracted from an aqueous 1 M nitric acid solution (contact time: 10 min, under agitation and at ambient temperature); a second organic phase comprising 30% (v/v) of TBP in HTP and 0.26 mol/L of 6-HIHA; a third organic phase comprising 30% (v/v) of TBP in HTP and 0.26 mol/L of 8-HIOA; and a fourth organic phase only comprising TBP in a proportion of 30% (v/v) in HTP. For the first test, an aliquot of the first organic phase was mixed, volume by volume, for 10 seconds and at ambient temperature with the second organic phase, and 4 ml of the mixture obtained were contacted for 5 minutes under agitation and at ambient temperature with 3 mL of a first aqueous phase comprising 1 mol/L of nitric acid and 9 g/L of uranium(IV). Thereafter, the contacted phases were separated from each other. The second test was performed in the same manner as the first but by replacing the second organic phase with the third organic phase. For the third test, another aliquot of the first organic phase, volume by volume, was mixed for 10 seconds and at ambient temperature with the fourth organic phase; 6 mL of the mixture obtained was placed in contact for 5 minutes, under agitation and at ambient temperature, with 3 mL of a second aqueous phase comprising 1 mol/L of nitric acid, 13 g/L of uranium(IV) and 0.26 mol/L of hydrazine. Thereafter, the contacted phases were separated from each other. Therefore, all the tests were conducted under identical initial conditions regarding acidity and concentrations of TBP, plutonium(IV) and uranium(IV), and with equivalent quantities of anti-nitrous agents (6-HIHA, 8-HIOA or hydrazine) in the organic phase/aqueous phase mixture having regard to the O/A volume ratios used. The contact time under agitation for 5 minutes was selected as representing the maximum residence time in the mixing part of an extractor such as used in a typical U/Pu partitioning scheme of the PUREX method. According to the reduction equilibrium of plutonium(IV) to plutonium(III) by uranium(IV) indicated previously, ½ mole uranium(IV) is consumed per mole of plutonium(III) produced. In these tests, the amount of uranium(IV) initially contained in the aqueous phases is about 1.3-1.4 times higher than the amount of plutonium(IV) initially contained in the organic phases. This excess of reducing agent was chosen to allow evaluation of the amount of uranium(IV) that is over-consumed, i.e. the consumption in addition to consumption solely due to the reducing reaction of plutonium(IV). After these tests, the concentrations of uranium(IV), plutonium and nitric acid were measured in each of the organic and aqueous phases: by visible spectrophotometry for uranium(IV), by α-spectrophotometry for plutonium and by potentiometric titration for nitric acid. The results of these measurements show that after a contact time of 5 minutes, the plutonium has quantitatively passed into the aqueous phase in oxidation state III (characteristic double peak at λ=560-600 nm), with an extremely low coefficient of distribution, comparable in the three tests (DPu=0.02). The reducing reaction of plutonium(IV) has therefore truly taken place. FIG. 2 shows the residual quantities of uranium(IV), expressed as percentages of the initial quantities of uranium(IV), obtained for the three tested anti-nitrous agents (6-HIHA, 8-HIOA and hydrazine), and the expected residual quantities of uranium(IV) for a consumption of uranium(IV) that is solely related to the reduction of plutonium(IV) by this reducing agent. As shown in this Figure, the quantities of uranium(IV) consumed in the presence of 6-HIHA and 8-HIOA are equivalent, even lower, than those expected for mere reduction of plutonium(IV) to plutonium(III). On the other hand, for hydrazine, an over-consumption of uranium(IV) is observed under the same operating conditions since there only remains 42% of uranium(IV) whereas there should remain 58% according to the stoichiometry of said reducing reaction. FIG. 3 shows the quantities of uranium(IV) consumed in organic phase and aqueous phase, obtained for the three tested anti-nitrous agents (6-NINA, 8-HIOA and hydrazine) and expressed as percentages of the expected quantities of uranium(IV) if uranium(IV) had solely been distributed between the two phases. This shows that, as expected, uranium(IV) is mostly consumed in organic phase since the reducing of plutonium(IV), initially contained in the organic phase, takes place in this phase. It also shows that uranium(IV) is less consumed in the presence of 6-HIHA or 8-HIOA than in the presence of hydrazine, thereby confirming the fact that hydroxyiminoalkanoic acids have greater anti-nitrous properties than hydrazine. In the presence of hydrazine, the consumption of uranium(IV) in organic phase is practically twice higher than in the presence of 6-HIHA or 8-HIOA since, contrary to the latter, hydrazine is not extractable in organic phase. On the other hand, uranium(IV) is scarcely consumed in aqueous phase. In the presence of 6-HIHA or 8-HIOA, uranium(IV) is consumed normally in the organic phase, i.e. in an amount needed to allow the reduction of plutonium. In aqueous phase, 6-HIHA appears to be just as efficient and even more efficient than hydrazine for stabilising uranium(IV) since there is no consumption of this reducing agent in the presence of this anti-nitrous agent. The operating conditions under which the foregoing tests were conducted and the results obtained for these tests are given in Table 1 below. TABLE IAnti-nitrous agent6-HIHA8-HIOAHydrazineInitial conditionsO/A volume ratio1.31.32Weight ratio U(IV) in aqueous phase/Pu(IV) in organic phase1.41.41.3[U(IV)] in aqueous phase (g/L)8.98.912.6[U(IV)] in aqueous phase (mol/L)0.0370.0370.053[HNO3] in aqueous phase (mol/L)1.01.01.0[Pu(IV)] in organic phase (g/L)4.64.64.9[anti-nitrous agent] in organic phase (mol/L)0.130.13—[anti-nitrous agent] in aqueous phase (mol/L)——0.26Danti-nitrous agent0.450.430DU(IV)0.80.80.8Aqueous phase after contacting (5 min)[anti-nitrous agent] estimated without consumption (mol/L)0.110.110.26[U(IV)] estimated without consumption (mol/L)0.0180.0180.020Estimated quantity of anti-nitrous agent without consumption63%64%100% Estimated quantity of U(IV) without consumption48%48%38%[U(IV)] estimate without consumption (g/L)4.34.34.8Measured [U(IV)] (g/L)4.43.54.7Quantity of consumed U(IV) in aqueous phase 0%19% 3%Measured [U(IV)] (mol/L)0.0190.0150.020Measured [Pu] (g/L)6.66.611Measured [Pu] (mol/L)0.0280.0270.045Measured [HNO3] (mol/L)0.900.820.99Aqueous volume (mL)333Organic phase after contacting (5 min)[anti-nitrous agent] estimated without consumption (mol/L)0.0490.0470[U(IV)] estimated without consumption (mol/L)0.0140.140.016Estimated quantity of anti-nitrous agent without consumption38%36% 0%Estimated quantity of U(IV) without consumption52%52%62%[U(IV)] estimated without consumption (g/L)3.43.43.9Measured [U(IV)] (g/L)1.701.740.3Quantity of U(IV) consumed in organic phase50%49%92%Measured [Pu] (g/L)0.110.090.23Organic volume (mL)446DPu0.0170.0140.021Pu balance110% 108% 113% Residual U(IV) balance76%65%42%Residual U(IV) balance without parasitic reactions63%63%58% 2.3—Ageing of the Organic and Aqueous Phases Once Separated To evaluate whether, for hydroxyimino alkanoic acids, there is a risk of oxidation of uranium(IV) to uranium(VI) and of reoxidation of plutonium(III) in all the stages dedicated to the U/Pu partitioning in a typical scheme of the PUREX method, the concentration of uranium(IV) in the organic and aqueous phases obtained after the stripping tests conducted under item 2.2 above, using 6-NINA and 8-HIOA as anti-nitrous agents, was monitored by visible spectrophotometry for several hours after their separation from one another. According to the O/A flow rates conventionally used in an industrial scheme or pilot test scheme of the PUREX method, the residence time of the aqueous phase in the extractors in which the operations conventionally known as «Pu stripping» and «U washing» for the U/Pu partitioning are conducted, does not exceed four hours whilst it is no more than two hours for the organic phase. The monitoring of the concentrations was therefore carried out over a time of 3 to 4 hours. The results are given in FIGS. 4A and 4B for 6-HIHA and in FIGS. 5A and 5B for 8-HIOA, FIGS. 4A and 5A corresponding to the concentrations of uranium(IV) measured over the first 30 minutes following after separation of the organic and aqueous phases, and FIGS. 4B and 5B corresponding to the concentrations of uranium(IV) measured over the entire length of monitoring time. As shown in these Figures, the concentration of uranium(IV), mixed with all the plutonium(III) in aqueous phase, is stable: there is therefore no risk of reoxidation of plutonium(III), or of oxidation of uranium(IV) in aqueous phase. In organic phase containing most of the nitrous acid, even if the concentration of uranium(IV) shows a greater reduction, the stability remains compatible with overall residence times of less than two hours since there remains some uranium(IV) after an ageing time of 3 hours. This means that 6-HIHA and 8-HIOA stabilise uranium(IV) sufficiently against its reoxidation by nitrous acid in organic and aqueous phases, so that it is maintained in sufficient quantity even after an ageing time of several hours. In all cases, the plutonium remained at oxidation state III during these few hours of ageing, which is the targeted objective for an efficient stripping of this actinide from an organic phase formed of TBP in HIP towards an aqueous nitric phase. 2.4—Management of 6-Hydroxyiminohexanoic and 8-Hydroxyiminooctanoic Acids Downstream of a Reductive Stripping Operation of Plutonium As shown in Table 1, most of the 6-HIHA and 8-HIHA after a reductive stripping of plutonium, is essentially in found in aqueous phase. Only a small proportion of these anti-nitrous agents remain in the organic phase. In a typical scheme of the PUREX method, the operation performed downstream of the reductive stripping of plutonium at the U/Pu partitioning step allows the stripping of uranium(VI) from the organic phase derived from this stripping operation towards an aqueous phase which comprises from 0.01 mol/L to 0.05 mol/L of nitric acid (ratio of O/A flow rates close to 1, temperature of 45° C.). The organic phase thus purified of plutonium and uranium is then reprocessed for recycling thereof using an aqueous solution comprising 0.3 mol/L sodium carbonate, followed by an aqueous solution comprising 0.1 mol/L sodium hydroxide (ratios of O/A flow rates 10-20, temperature of 45° C.). Stripping tests were therefore carried out using: as organic phases: two phases the first comprising 30% (v/v) of TBP in HTP and 0.05 mol/L of 6-NINA, and the second 0.05 mol/L of 8-HIOA; and as aqueous phases: aqueous solutions mimicking those in terms of acidity or basicity respectively used in a typical scheme of the PUREX method to strip uranium(VI) and regenerate the organic phase for recycling thereof. These tests were conducted at ambient temperature using an O/A volume ratio of 1 and a contact time between the organic and aqueous phases of 2 minutes under agitation. Measurements of the concentration du 6-NINA and 8-HIOA in the aqueous phases (by high performance liquid chromatography) and in the organic phases (by gas phase chromatography) obtained after these tests showed that the coefficients of distribution of 6-NINA and 8-HIOA are near-constant for acidities of between 0.01 mol/L and 0.05 mol/L. On the other hand, they also show that 6-HIHA and 8-HIOA pass quantitatively into the aqueous phase after only one contacting with a sodium hydroxide solution if the amount of base contained in this solution is sufficient to neutralise the fraction of these compounds contained in the organic phase. These anti-nitrous agents can therefore easily be removed from the organic phase resulting from stripping of uranium(VI), via the basic treatment to which this organic phase is subjected in a typical scheme of the PUREX method, for recycling thereof. [1] WO-A-2006/072729 [2] WO-A-2011/000844 [3] WO-A-2008/148863 [4] FR-B-1 349 281 [5] Ishigaki et al., Bull. Chem. Soc. Jap., 1977, 50(3), 726-730 [6] Ayorinde et al., J. Am. Oil Chem. Soc., 1997, 74(5), 531-538 [7] Jackman et al., J. Org. Chem., 1982, 47(10), 1824-1831 [8] Thiele et al., ACS Chem. Biol., 2012, 7(12), 2004-2011 [9] US-A-2008/0306153 [10] Rajabi et al., Synth. Comm., 2014, 44(8), 1149-1154 [11] Utsukihara et al., Tet. Lett., 2006, 47(52), 9359-9364 [12] Carrera et al., Tet. Lett., 2009, 50(38), 5399-5402 [13] Bouet et al., Tet. Asym., 2008, 19(20), 2396-2401
039719553	abstract	Container for use in the shipment and storage of radioactive material including a wrench-type cover. The cover includes a lid and a wrench-type attachment dimensioned so as to engage the cap of an enclosed bottle and provide space in which an absorbent pad can be located.
047972483	description	On referring to FIG. 2a, it can be seen that the first stage of dismantling a nuclear fuel assembly like that diagrammatically shown in FIG. 1 consists of separating from the remainder of the assembly, the upper end fitting (d), together with the sections (b.sub.1) of the guide tubes remaining attached thereto. This operation is carried out by internal cutting of the guide tubes at a certain distance below the upper end of rods (a), the assembly being considered vertically in the position which it occupies in the reactor core. Generally, the upper grid of the assembly is also dismantled during this operation, because its presence might subsequently prevent a correct use of the gripping apparatus according to the invention. It is pointed out that this first dismantling operation is of a conventional nature and does not form part of the invention. It will therefore not be described in greater detail. The second stage of dismantling consists of extracting the group of rods (a) from the remainder of the assembly framework constituted by the lower end fitting (e) (FIG. 1), the remaining grids (c) and the remaining parts (b.sub.2) of the guide tubes. According to the invention, this second stage is performed in a single operation diagrammatically illustrated in FIG. 2b using a gripping apparatus 10, which will now be described in detail with reference to FIGS. 3 to 6. To facilitate understanding, gripping apparatus 10 is allocated an orthonormalized coordinate system XYZ, in which the axes X and Y extend in two directions defined by the square grid formed by the rods to be gripped, axis Z being parallel to the axes of the rods, when a bundle of rods is gripped by apparatus 10. FIGS. 3 and 4 show that the gripping apparatus according to the invention comprises a body 12 constituted by a central portion 14 and two identical side portions 16a, 16b disposed on either side of the central portion 14. FIG. 4 shows that the central portion 14 comprises a rectangular or square flat plate 18, whose dimensions slightly exceed the overall dimensions which the bundle of rods (a) of an assembly have in section. This plate is parallel to plane X, Y and its sides are oriented in directions X and Y. Plate 18 is traversed by cylindrical perforations 20, whose axes are parallel to direction Z. Perforations 20 are disposed in accordance with a grid identical to the square grid formed by the group of rods (a) to be gripped. For example for a conventional square section assembly, said grid comprises 17 rows in direction Y of at the most 17 rods each. However, no perforation is provided at the locations previously occupied by the guide tubes in the group of rods. The diameter of the perforations 20 slightly exceeds the external diameter of the rods to be gripped. On the face of plate 18 opposite to the face by which rods (a) penetrate perforations 20 (i.e. on the upper face of plate 18 considering FIG. 4), said perforations issue into a rectangular recess 22. The section of this recess in plane X, Y is identical to that of plate 18. As is more specifically shown by FIG. 3 in its part closest to the perforated plate 18, recess 22 is subdivided into passageways 26 by planar, parallel partitions 24 extending parallel to plane Y, Z between lateral portions 16a, 16b of body 12. Passageways 26 all have the same dimensions. More specifically, the partitions 24 are disposed in such a way that two adjacent rows of holes 20 (considered in direction Y) issue into each of the passageways 26. In the example of an assembly with a square section having 17 rows of at the most 17 rods, there are nine passageways 26, as illustrated by FIG. 3, whereby only one row of rods is received in the lateral passageways (that at the top in FIG. 3). As illustrated in FIG. 4, recess 22 is closed on the side opposite to plate 18 by a part 28 fixed to the central portion 14 of body 12, e.g. by screws 30. Part 28 is also traversed by cylindrical perforations 32 arranged along a grid identical to that formed by perforations or holes 20, perforations 20 and 32 being aligned in pairwise manner. Perforations 32 also have a diameter slightly exceeding the external diameter of the rods (a) to be gripped. As is more specifically illustrated in FIG. 3, a row of mobile cross-shaped members 34 is placed in each of the passageways 26 defined by partitions 24. These member 34 will be described in greater detail hereinafter. It is merely pointed out that they are placed in each passageway in such a way that two holes 20 belonging to two adjacent rows in direction Y (as well as the facing holes 32) issue between two adjacent crosses of the same passageway. The mobile members 34 placed at the ends of each of the passageways 26 have a slightly different shape. More specifically, the face thereof turned towards the end of the passageway is planar. The gripping apparatus according to the invention also comprises locking or clamping means located in the lateral portions 16a, 16b of body 12. These locking means firstly comprise in each of the lateral portions 16a, 16b, a series of plungers 36a, 36b. In the considered example, each of the series or rows of plungers is constituted by nine identical plungers. The plungers 36a, 36b having a generally cylindrical configuration are aligned pairwise parallel to direction Y. Moreover, the axes of all the plungers 36a, 36b are all placed in the same plane parallel to plane X, Y. Each plunger 36a, 36b is received in a bore 38a, 38b formed in portion 16a, 16b respectively of body 12 and issuing into recess 22. More specifically, a bore 38a, 38b issues at each of the ends of passageways 26 defined by partitions 24. Each of the plungers 36a, 36b comprises a front part 40a, 40b, whereof the convex end abuts against the planar rear face of the corresponding mobile member 34'. Each of the plungers 36a, 36b also comprises a rear part 42a, 42b able to slide in direction Y with respect to the front part 40a, 40b. The front parts 40a, 40b and rear parts 42a, 42b of each of the plungers are subject to the action of a stack of elastic washers 44a, 44b so that move away from one another, tending to increase the length of each of the plungers 36a, 36b. The rear part 42a, 42b of the plungers of each row of plungers 36a, 36b issues into a recess 46a, 46b formed within the corresponding portion 16a, 16b of body 12. Each of the rows of plungers 36a, 36b cooperates with actuating means respectively located in recesses 46a, 46b. These actuating means are in each case constituted by a wedge device formed respectively by two parts 48a, 54a and 48b, 54b. Parts 48a, 48b are positioned so as to slide in direction Y in each of the recesses 46a, 46b. Each of the parts 48a, 48b has a planar front face 50a, 50b, parallel to plane X, Z and on which bears the convex end of each of the rear parts 42a, 42b of the corresponding plungers. The guidance of parts 48a, 48b in recesses 46a, 46b is obtained by sliding the end faces of the parts in direction X on planar surfaces formed in the recesses parallel to plane Y, Z. Moreover and as can best be seen in FIG. 4, each of the parts 48a, 48b has in its central portion in direction X an extension having a section in the form of an O. This configuration makes it possible to ensure a satisfactory guidance of these parts during their displacement. Thus, end faces of portions 16a, 16b spaced in direction Z are in sliding contact with planar surfaces parallel to the plane X, Y formed within O-shaped extensions of parts 48a, 48b. As can be seen in FIG. 3, each of the parts 48a, 48b is provided on its rear face with two ramps 52a, 52b, which are terminated by planar portions parallel to plane X, Y. The displacement of each of the parts 48a, 48b in direction Y is controlled by another part 54a, 54b interposed between the rear planar face 56a, 56b of recess 46a, 46b, parallel to plane X, Y and the rear face of the corresponding part 48a, 48b. Each of the parts 54a, 54b is extended out side body 12, in direction X, so as to be displaceable in said direction in one or other sense, e.g. under the action of a not shown jack. Each part 54a has a planar rear face 58a, 58b, which slidingly bears on the rear face 56a, 56b of the corresponding recess. The front face of each of the parts 54a, 54b is substantially complementary of the rear face of each of the parts 48a, 48b. More specifically, each part 54a, 54b also has two ramps 60a, 60b spaced by the same distance as ramps 52a, 52b and issuing at their ends on the planar portions parallel to plane X, Z. As is shown to the left of FIG. 3, when parts 54a, 54b occupy their unlocking position, in which they are removed to the maximum from body 12 of the apparatus in direction X, ramps 60a, 60b face ramps 52a, 52b. This position is stable, because the planar portions formed at the foot of ramps 52a, 52b of parts 48a, 48b bear on the planar portions formed at the top of ramps 60a, 60b of parts 54a, 54b. Parts 48a, 48b are then retracted rearwards within recesses 46a, 46b. Under the action of elastic washers 44a, 44b, the rear part 42a, 42b of each of the plungers is also drawn rearwards. The compression of the elastic springs is thus substantially eliminated, so that no locking force is exerted in direction Y by the front portions 40a, 40b of the plungers on the end members 34'. However, as illustrated to the right in FIG. 3, when parts 54a, 54b are forced to the maximum into recesses 46a, 46b in direction X, said parts push back parts 48a, 48b towards the front due to the wedge effect, as a result of the cooperation of ramps 52a, 52b and 60a, 60b. Thus, a stable locking position is attained, in which the planar portions formed at the top of ramps 52a, 52b of parts 48a, 48b bear on the planar portions formed at the top of ramps 60a, 60b of parts 54a, 54b. In this position, the rear portions 42a, 42b of the plungers are also pushed back to the maximum in the forwards direction in direction Y, which has the effect of compressing the elastic washers 44a, 44b. Due to this compression, a locking force is applied by the front portions 40a, 40b of the plungers on the mobile end members 34'. As is more particularly illustrated in FIG. 4, the gripping apparatus also comprises a grid 62 ensuring a prior positioning of the ends of rods (a) before they penetrate the apparatus. Grid 62 is fixed to the central portion 14 of body 12 from the side of plate 18 opposite to recess 22. Grid 26 comprises a frame by which it is fixed to body 12, e.g. by means of screws 64 and two rows of parallel thin sheets regularly arranged in directions X and Y, so as to define square cavities between them. The dimensions of these cavities are such that each of the holes 20 issues into one of the cavities. If the ends of certain of the rods to be gripped are slightly staggered with respect to the grid which they formed when the assembly was new, plate 62 makes it possible to recenter these ends in order to facilitate the penetration thereof into holes 20. The gripping apparatus according to the invention also comprises an ejector 66, whose main function is to permit the ejection of rods (a) from the apparatus after said rods have been transported and the locking force has been slackened. As shown in FIG. 4, said ejector 66 essentially comprises a flat plate 68 parallel to plane X, Y and a group of bars 70. Plate 68 is placed outside body 12 facing the central portion 14 of the latter and more specifically on the side of part 28 closing recess 22. Preferably, the generally square plate 68 is slidingly received on columns 72 projecting over the corresponding face of body 12 parallel to direction Z. Columns 72 traverse plate 68 in the vicinity of each of its angles. A spring 74 is compressed between plate 68 and a shoulder formed at the end of each column 72, so as to move plate 68 towards plate 28. Bars 70 are fixed to the face of plate 68 oriented towards plate 28 in accordance with a grid identical to that formed by perforations 20 and 32. Moreover, these bars 70 have a uniform circular section, whose diameter is substantially identical to that of the rods to be gripped. The axis of each of the bars coincides with the axis of one of the pairs of perforations 20, 32, the action of springs 74 has the effect of making said bars 70 enter each of the holes 32, then pass between mobile members 34 and finally into each of the perforations 20, as illustrated by the left-hand part of FIG. 4. When it is wished to use the described apparatus for gripping the ends of a group of rods (a), in order to extract same from a nuclear fuel assembly, the ends of the rods are firstly introduced into perforations 20, said operation being facilitated by the presence of grid 62. Generally this operation is performed whilst maintaining fixed the assembly containing the rods and by progressively moving the gripping apparatus 10 so as to introduce the ends of the rods into perforations 20, then between members 34 and finally into perforations 32, whilst forcing back ejector 66 in such a way that only the ends of bars 70 remain introduced in perforations 32. This situation is shown to the right of FIG. 4. As is more specifically illustrated by FIG. 5, the introduction of the ends of rods (a) into the gripping apparatus is performed in such a way that the upper end fitting (a.sub.1) of each of the rods completely penetrates the perforation 32 formed in part 28. Thus, the actual gripping takes place on can (a.sub.2), below the welding bead (a.sub.3) conventionally separating the latter from the upper end fitting. This precaution makes it possible to guarantee the quality of the gripping on each of the rods, despite the displacement along Z generally existing between the ends of the rods and which is shown in FIG. 5. This displacement is due to the differential elongation of the rods of the same assembly following irradiation. In this position, part of each of the rods to be gripped traverses the passageways 26 defined by partitions 24. As is more specifically illustrated in FIG. 6, on starting from the end of each of the passageways, one successively finds the front rounded part 40a, 40b of the corresponding plunger, the mobile end member 34', two juxtaposed rods (a), a mobile member 34, two other rods (a), etc. More specifically, the mobile end member 34' has a planar rear face on which bears the convex end of the plunger part 40b. On its front face, member 34' has two planar surfaces able to bear on each of the rods (a) and between which projects an intermediate branch 76'. Each of the mobile members 34 is shaped like a cross and whereof one branch positioned transversely with respect to the corresponding passageway, serves as a bearing support by its opposite faces for the four adjacent rods. The other branch 76 of the cross formed by each of the members 34 is constituted by two portions projecting on either side of the first branch between adjacent rods (a). The ends of branches 76, 76' are planar and normally spaced by a clearance (j). During locking, if a crushing of the cans of rods (a) leads to a deformation of said cans corresponding to clearance (j), branches 76, 76' bear against one another and prevent any increase in the force applied on the rods. Branches 76, 76' consequently make it possible to limit the locking force individually applied to each of the rods. It has been seen hereinbefore that the spaces initially occupied by the guide tubes in the assembly constitute spaces in the bundle of rods (a) to be gripped. Moreover, as illustrated in FIG. 3, the assembly can have an uneven number of row of rods, so that one of the lateral passageways only contains one row of rods. In order that the effectiveness of this locking is not disturbed by these spaces, rollers 78, whose axis is oriented in the direction of axis Z, are placed at the locations corresponding thereto in passageways 26. The length of these rollers is slightly less than the height of the corresponding passageway and the diameter thereof is substantially identical to the diameter of the rods. Thus, the grid is completed and the effectiveness of locking is retained. As indicated hereinbefore, the actual locking or clamping is performed by moving the parts 54a, 54b towards the interior of recesses 46a, 46b, e.g. using jacks. Through the cooperation of ramps 52a, 52b and 6a, 60b, parts 48a,48b are forced back in the manner shown to the right of FIGS. 3 and 4, in order to arrive in a stable locking position, where the parts are wedged against the planar portions of parts 54a, 54b. In this stable position, a locking force is applied in each of the passageways 26 to the end parts 34' by means of plungers 36a, 36b and elastic washers 44a, 44b carried by the latter. Thus, in each passageway, there is the locking of two rows of rods, each rod being gripped between two adjacent mobile members 34. Moreover, if there is excessive crushing of the can of certain of the rods, said crushing is limited by the abutment of the ends of the branches 76 of mobile members 34 between which said rods are locked. When the rods have been gripped in this way, they can be transported with the aid of apparatus 10 up to a rod release station, where is provided in fixed manner another set of jacks for actuating parts 54a, 54b. as a result of these jacks, parts 54a, 54b are brought into the position shown to the left in FIG. 3, in order to reduce the locking force applied to the ends of the rods. Under the action of springs 74, the rods are ejected out of the apparatus by introducing bars 70 into perforations 32 and 20, as illustrated to the left in FIG. 4. As a variant, springs 74 can be eliminated. The rods (a) are then ejected from apparatus 10 by the abutment of plate 68 against a fixed abutment located at the rod release station. Obviously, the invention is not limited to the embodiment described in exemplified manner hereinbefore and covers all variants thereof. It is firstly pointed out that there could be twice as many partitions 24, the passageways 26 defined between said partitions then receiving in each case a single row of rods (a). Moreover, the filling of the spaces of the group or bundle by rollers 78 can be avoided by using differently shaped parts 34 at said spaces. Finally, it is also possible to use different clamping or locking means from those described for exerting the longitudinal locking force within each of the passageways. In particular, said locking means might only be placed in one of the lateral portions of the body of the apparatus. Moreover, elastic washers 44a, 44b could be replaced by any other equivalent elastic devices, such as compression springs.
047987006	summary	BACKGROUND OF THE PRESENT INVENTION The invention relates to ceramic installations and more particularly to ceramic reflectors for use in nuclear reactors. Ceramic installations are utilized in gas-cooled, high temperature reactors as side, bottom and roof reflectors intended to reduce losses caused by the migrating of neutrons. At least part of the neutrons moving to the outside are to be reflected back into the fission zone of the reactor, the so-called reactor core. The neutron flux increased at the edge of the fission zone by the reflector effect raises the output produced by unit mass of the fissionable material, leading to the improved utilization and more economical consumption of the nuclear fuel. Highly purified graphite is used in gas-cooled, high temperature nuclear reactors as the material for ceramic installations. It is relatively inexpensive, has adequate strength and may be processed mechanically. It is refractory and has good thermal conductivity. A disadvantage is the change in its crystalline structure caused by neutron and gamma radiation and expressed by changes in mechanical strength and in volume. Under the effect of temperature and high neutron fluxes, graphite expands at first negatively, but then positively beginning at a point of reversal, with increasing fluxes, which go beyond the original dimensions of the graphite body. The process is displaced with rising temperatures toward lower fluxes. The differences in expansion within the structural part--in keeping with the flux distribution, at the onset of the irradiation the block layers close to the surface of the front facing the core tend to become shorter to a relatively greater extent due to shrinkage than the deeper layers--are the cause of the generation of residual stresses. To reduce these residual stresses, it is necessary to provide relief by expansion equalization. This may be obtained advantageously by slit surface structures which are equivalent to a dimensional reduction of parts of the graphite block. In more recent developments of gas-cooled, high temperature nuclear reactors, in particular those of lower capacity (approximately 100 MWel) and with correspondingly smaller core diameters, in place of absorber rods inserted directly into the pile of spherical fuel elements, small absorber elements in the spherical form are provided for the shutdown of the reactor and are introduced into corresponding cavities of the reflectors. In a manner similar to the AVR nuclear power plant in Julich, in the core of which nose-like projections with vertical cavities, the so-called nose stones, are provided to receive the control and shutdown rods, the newer gas-cooled high temperature nuclear reactors presently in the planning stage are equipped with nose stones of this type, but here they are intended for shutdown rods only. The nose stones are ashlar-shaped graphite blocks extending radially from the side reflector, to which they are physically joined, over the entire height of the reactor core into which they are projecting. In view of the above-mentioned volume variations and the residual stress state caused by them in the irradiated graphite blocks, the surfaces facing the core of the latter are provided with vertical and horizontal surface slits, representing a resolution of the original large surface into small individual rills. To control stresses in the nose stones, the cavities provided for the introduction of the absorber elements are connected with the core by means of gaplike, vertically disposed continuous openings. These openings reduce the residual stresses in the nose stones to tolerable levels. However, the afore-mentioned expansions lead in the course of the operation to a widening of the openings to such an extent that the separation of the absorber material and the fuel elements is no longer assured and the absorber elements are able to exit from the cavities and fuel elements can enter them. Based on this state of the art, it is the object of the invention to provide measures for the design of ceramic installations which are simply and cost effectively realized and which prevent in a highly reliable manner the aforementioned deficiencies, in particular the passage of absorber and/or fuel elements through the continuous opening. SUMMARY OF THE PRESENT INVENTION In accordance with the present invention, the innermost gap width, i.e., the distance of the gap surfaces defining the gap from each other on the innermost side adjacent the cavity is determined such that it will correspond at most to one-half of the size of the minimum dimension of an absorber element present in the cavity. This insures that no absorber element can become jammed in or pass through the gap and hinder the deformation equalization for which the gap or continuous opening has been provided. Simultaneously, this determination also takes into account the fact that the deformations caused by neutron irradiation are essentially confined to a zone close to the surface of the graphite nose stone facing the core, so that the width of the gap varies only slightly inside the cavity and that therefore said deformations are not hindered and additional stresses are avoided. In addition, the individual absorber elements are appreciably smaller than the fuel elements, so that by means of the spalt geometry described above, the passage of both the absorber elements and the fuel elements is safely prevented. In a further embodiment of the invention the continuous opening is positioned on the front side of the nose stone and provided with an inserted graphite blocking member. This blocking member is guided positively in grooves molded opposingly into the surfaces of the opening. It is set loosely and transversely in the opening and assures the uniform absorption of neutron radiation by the absorber material inserted into the cavity, without preferential treatment being given to any spatial zone due to the absence of reflecting graphite. Another embodiment of the invention takes this condition into account by the fact that the gap opening comprises a continuation of a slit-like groove on the face of the nose stone projecting into the core. Here again a direct impact on absorber material of neutron radiation is almost entirely excluded. It has been found to be advantageous in this context to curve the opening away from the central portion of the core thereby obtaining a stronger reflection of the neutrons entering the gap and preventing the irradiation of the inner graphite areas. Further advantageous embodiments of the invention concern the design of the gap geometry with parallel gap surfaces or with surfaces expanding from the inside out. The latter characteristic takes into consideration the aforementioned deformation, which appears primarily on the surface of the nose stone facing the core and which in the case of extended irradiation times, i.e., over the entire period of operation, is manifested by a volume increase.
	description	This application claims the benefit of U.S. Provisional Application No. 61/625,326 filed Apr. 17, 2012. U.S. Provisional Application No. 61/625,326 filed Apr. 17, 2012 is hereby incorporated by reference in its entirety. The following relates to the nuclear power reactor arts, nuclear reaction coolant system arts, nuclear power safety arts, and related arts. Light water nuclear reactors are known for maritime and land based power generation applications and for other applications. In such reactors, a nuclear reactor core comprising a fissile material (for example, 235U) is disposed in a pressure vessel and immersed in primary coolant water. The reactor core heats the primary coolant in the pressure vessel, and the pressure vessel includes suitable devices, such as heaters and spargers, for maintaining the primary coolant at a designed pressure and temperature, e.g. in a subcooled state in typical pressurized water reactor (PWR) designs, or in a pressurized boiling water state in boiling water reactor (BWR) designs. Various vessel penetrations take primary coolant into and out of the pressure vessel. For example, in some PWR designs primary coolant is passed through large-diameter penetrations to and from an external steam generator to generate steam for driving a turbine to generate electrical power. Alternatively, an integral steam generator is located inside the reactor pressure vessel, which has advantages such as compactness, reduced likelihood of a severe loss of coolant accident (LOCA) event due to the reduced number and/or size of pressure vessel penetrations, retention of the radioactive primary coolant entirely within the reactor pressure vessel, and so forth. Additional smaller diameter vessel penetrations are provided to add primary coolant (i.e., a makeup line) or remove primary coolant (i.e., a letdown line). These lines are typically connected with an external reactor coolant system inventory purification device (RCI) that maintains a reservoir of purified primary coolant. Further vessel penetrations may be provided to connect with an emergency condenser, or for other purposes. Light water reactors must be evaluated to determine their response in the event that a pipe outside of the reactor vessel breaks and a loss of coolant accident (LOCA) occurs. The compact integral reactor design was developed, in part, to minimize the consequence of an external pipe break. However, the integral reactor designs still utilize small bore connecting piping that transports reactor coolant to and from the reactor vessel. Breaks in these pipes can cause a LOCA, and must be evaluated as design basis accidents. In accordance with one aspect, a nuclear reactor comprises: a nuclear reactor core comprising a fissile material; a pressure vessel containing the nuclear reactor core immersed in primary coolant disposed in the pressure vessel; and an isolation valve including a mounting flange secured to a wall of the pressure vessel and a valve body disposed in the wall or in a flange assembly including the mounting flange, the isolation valve closing responsive to a pressure difference across the valve exceeding a threshold pressure difference. In accordance with another aspect, a system comprises: at least one coolant pump configured to pump coolant water into or out of an associated nuclear reactor vessel; at least one external coolant conduit connecting said at least one coolant pump with the associated nuclear reactor vessel; and a vessel isolation valve having a mounting flange configured to connect with a mating flange of a vessel penetration through an outer wall of the associated nuclear reactor vessel. The vessel isolation valve fluidly connects with the at least one external coolant conduit. The vessel isolation valve is configured to block outward flow from the pressure vessel when a pressure differential across the valve exceeds prescribed criteria. The vessel isolation valve further includes: a valve seat defined in the mounting flange; a moveable valve member movable between an open position permitting flow through the vessel isolation valve and a closed position seating against the valve seat to block flow through the vessel isolation valve; and a biasing member that biases the valve member towards the open position. In accordance with another aspect, an isolation valve comprises: a mounting flange configured to connect with a mating flange of a pressure vessel; a valve seat formed into the mounting flange; and a valve member movable between an open position permitting flow through the isolation valve and a closed position in which the valve member seals against the valve seat to block flow through the isolation valve. The valve member is disposed inside the mounting flange or is arranged respective to the mounting flange so as to be disposed inside the mating flange of the pressure vessel when the mounting flange is connected with a mating flange of a pressure vessel. The isolation valve optionally further comprises a biasing member operatively connected to the valve member to bias the valve member towards the open position. If included, the biasing member is suitably configured to provide bias effective to keep the valve member in the open position except when a differential fluid pressure across the isolation valve and directed outward from the pressure vessel exceeds a threshold pressure. In accordance with another aspect, an apparatus comprises a pressure vessel including a mating flange and an isolation valve as set forth in the immediately preceding paragraph whose mounting flange is connected with the mating flange of the pressure vessel. In accordance with another aspect, an apparatus comprises a nuclear reactor comprising (i) a pressure vessel including a mating flange and (ii) a nuclear reactor core comprising fissile material disposed in the pressure vessel, and further includes an isolation valve as set forth in the immediately preceding paragraph whose mounting flange is connected with the mating flange of the pressure vessel of the nuclear reactor. FIG. 1 is a schematic illustration of a nuclear reactor including a pressure vessel 10. The pressure vessel 10 contains a nuclear reactor core 11 (shown in phantom) disposed at or near the bottom of the pressure vessel 10 and immersed in primary coolant water also disposed in the pressure vessel 10. The pressure vessel 10 further contains numerous internal components that are not visible in FIG. 1 but which are known in the art, such as structures defining a primary coolant flow circuit, e.g. a hollow cylindrical central riser defining a hot leg inside the riser and a cold leg in a downcomer annulus (e.g., flow region) defined between the central riser and the pressure vessel 10, and neutron-absorbing control rods and associated drive mechanisms for controlling reactivity of the nuclear reactor core. Some embodiments, e.g. integral pressurized water reactor (PWR) designs, also include one or more steam generators disposed inside the pressure vessel, typically in the downcomer annulus. A reactor coolant system inventory purification device (RCI) 12 is provided to maintain the quantity and purity of primary coolant inside the pressure vessel. A makeup line 14 delivers primary coolant from the RCI 12 to the pressure vessel 10, and a letdown line 16 removes primary coolant from the pressure vessel 10 into the RCI 12. The RCI 12 includes a pump 17 and other water processing components (not shown) for purifying and storing reserve primary coolant, injecting optional additives such as a soluble boron compound (a type of neutron poison optionally used to trim the reactivity), or so forth. Integral isolation valves 20 are provided at respective vessel penetration locations where the makeup line 14 and letdown line 16 pass through an outer wall 18 of the pressure vessel 10. The integral isolation valves 20 are configured to control flow into and/or out of the pressure vessel 10 through the makeup line 14 and letdown line 16 such that, during a LOCA, flow of coolant out of the pressure vessel 10 is automatically blocked. Turning to FIGS. 2 and 3, an exemplary integral vessel isolation valve 20, hereinafter referred to as simply an isolation valve 20, generally includes a biased open axial flow stop valve that is bolted or otherwise secured to a vessel penetration flange 22 providing a fluid penetration through the outer wall 18 of the reactor pressure vessel 10. As seen in FIG. 2, the exemplary isolation valve 20 generally includes a valve body 24 having a mounting flange 28 for securing the valve body 24 to the mating flange 22 of the reactor pressure vessel 10. The mounting flange 28 includes a plurality of bolt holes 32 for receiving bolts 36 or other fasteners for securing the valve body 24 to the flange 22 of the reactor pressure vessel 10. The flange 22 of the pressure vessel 10 may be inset into or flush with the wall 18 of the pressure vessel 10, or may extend outward as shown in FIGS. 2 and 3, e.g. a forging or casting integrally formed with the wall 18 or welded to the wall 18. The flange 22 has corresponding holes for receiving fasteners (e.g., bolts 36). Suitable sealing elements, such as gaskets or o-rings, can be provided for sealing the connection of the flanges 22, 24. As best seen in FIG. 3, which is a cross-sectional view of the isolation valve 20 taken through a central longitudinal axis thereof, the exemplary isolation valve 20 includes a valve member in the form of a piston 38 that is supported within the valve body 24 for reciprocating axial movement. The piston 38 is configured to seal against a valve seat 42 that is generally formed by a radially-inwardly extending shoulder within a central bore 44 of the valve body 24. When mounted to the pressure vessel 10, the piston 38 and valve seat 42 are located inside the wall 18 of the reactor pressure vessel 10, or at least inside the flange 22 extending away from the wall 18 (in some embodiments in which the flange protrudes away from the wall 10). The function of the isolation valve 20 is to seal the penetration 22 in the reactor pressure vessel 10 in the event of a pipe break or other sudden loss of pressure in the pipes external to the reactor pressure vessel 10, such as makeup line 14 and/or letdown line 16. Such sealing thus occurs at or within an outer boundary of the pressure vessel 10. As noted, the valve body 24 is generally hollow and has internal bore 44 extending from a first axial end to a second axial end thereof. The first axial end of the valve body 24 is configured to be received within the penetration 22 and serves as a flow inlet or outlet 54 (depending on the direction of flow through the isolation valve 20). The end 54 may be an open end in fluid communication with the downcomer annulus or other plenum defined inside the pressure vessel 10, or may connect to internal piping or other flow passages (not shown) within the pressure vessel 10. The second axial end of the valve body 24 is enclosed by a spring cover 56 which, as will be described in more detail below, houses a spring 58 for biasing the piston valve member 38 to an open position. An opening 60 in the valve body 24 communicates with the central bore 44 such that fluid can flow between the central bore 44 and the opening 60. The opening 60 functions as a flow inlet or outlet (again, depending on the direction of flow through the isolation valve 20). The opening 60 can be connected to suitable piping, such as makeup line 14 or letdown line 16, depending on its specific application. As noted above, a movable valve member in the form of piston 38 is supported within the central bore 44 of the valve body 24 for reciprocating axial movement between an open position (as shown in FIG. 3) permitting flow through the bore 44, and a closed position whereat the piston 38 seals against the valve seat 42 within the central bore 44, thus blocking flow through the central bore 44. In the illustrated embodiment, the valve seat 42 is generally coaxially aligned with the mounting flange 28 such that when the valve body 24 is secured to a pressure vessel, the valve seat 42 is disposed within the interior of the pressure vessel 10, or within the wall 18, or within the vessel penetration flange assembly 22, 28 (that is, an assembly of secured flanges 22, 28 that does not include any intervening piping). A rod 64 is connected with the piston 38 and extends axially through the central bore 44 and protrudes from the second axial end of the valve body 24. The protruding end of the rod 64 is operatively connected to a biasing member in the form of the spring 58 that is contained within spring cover 56. Spring 58 is in compression and acts between the spring cover 56 and the rod 64 to bias the piston 38 towards the open position as shown in FIG. 3. Absent any flow through the central bore 44, the spring 58 generally maintains the piston 38 in its open position. During normal operation of the isolation valve 20, the spring 58 is configured to maintain the piston 38 in its open position to permit flow between the axial inlet/outlet 54 in the valve body 24 and the inlet/outlet 60 of the valve body 44. That is, the spring 58 is configured to apply enough force to the piston 38 to permit a desired amount of flow through the valve 20 in either direction during normal operation. However, if the pressure on the inside of the pressure vessel 10 exceeds a prescribed pressure threshold, such pressure acting on piston 38 will overcome the preload spring bias thereby shifting the piston 38 to the closed position sealing the piston 38 against valve seat 42 and preventing flow from the interior of the pressure vessel through the penetration 22. It should be appreciated that, when installed on a pressure vessel 10, the valve 20 operates to seal the penetration 22 automatically when the pressure differential across the valve exceeds a threshold value. The threshold value can be set at least in part by the amount of bias applied to the piston 38 by spring 58. For example, during normal operation the pressure differential across the valve 20 may be minimal, and the spring 58 therefore would act to keep the piston 38 in the open position. In some instances, the pressure differential across the valve may increase. For example, a break in an external pipe connected to the valve 20 would result in a decrease in the pressure at inlet/outlet 60. If this decrease in pressure is large enough, it may have the effect of increasing the pressure differential between inlet/outlet 54 and inlet/outlet 60 such that the bias applied to the piston 38 by spring 58 would be overcome and thereby shift the piston to the closed position. The piston 38 would then remain in the closed position as long as the pressure differential that shifted the valve to the closed state continues to exist. It will be appreciated that spring 58 can be configured to provide different levels of biasing force to the piston 38. For example, a plurality of springs having various spring constants can be provided, and a given spring chosen and installed in to the valve 20 depending on a particular application. Alternatively, or in addition, a spring preload mechanism can be used to apply a preliminary preload to spring 58 to vary the force applied to the piston 38. Such a spring pretension mechanism can include a spring cover 56 having an axial length that is less than the axial length of the spring 58 such that, when installed, the spring cover 56 compresses the spring 58. By providing spring covers of different axial length, more or less preload can be applied to a given spring. Since the spring and spring cover of the valve shown in FIGS. 2 and 3 are located external to the pressure vessel 10 when the valve 20 is installed thereon, conventional materials can generally be used for the spring element and/or spring cover. The spring cover 56 and spring 58 are not safety-critical, because failure or removal of the spring cover 56 and/or spring 58 would simply remove the bias force keeping the isolation valve open and cause the valve to close to prevent coolant from escaping from the pressure vessel. (Alternatively, if there is positive flow from the opening 60 to the inlet/outlet 54 the valve may stay open in spite of the failure of the biasing mechanism 56, 58; but, in that case again no fluid would escape from the pressure vessel 10 because the flow would be into the vessel 10). It should be appreciated, however, that the spring and/or portions thereof could extend into the pressure vessel 10 or into the wall 18 or flange 22, or be located entirely within the pressure vessel. Turning to FIG. 4, another exemplary isolation valve 80 is illustrated having a spring element that is configured to be supported within a pressure vessel wall 82 (or within a welded flange extending therefrom) when installed. In this embodiment, the valve 80 is supported within a generally cylindrical valve body 84 that includes a thermal sleeve 86. The valve body 84 is supported within a bore 88 extending through the vessel wall 82. An annular space is formed between the thermal sleeve 86 and the bore 88 in which primary coolant can circulate for reducing thermal shock to fluid flowing into the reactor pressure vessel 82. In the illustrated embodiment, the valve body 84 is welded or otherwise secured to a mounting flange 90 that is configured to be bolted to a mating flange 92 that is flush with, inset into, or protrudes from the pressure vessel wall 82. A central passageway 98 in the mounting flange 90 communicates with a central passage 102 of the valve body 84. Supported within the central passage 102 of the valve body is a moveable valve member 108 that is biased to an open position by compressed spring 112. In this regard, spring 112 is interposed between radially inwardly extending ribs or vanes 113 of the valve body 84 and a spring retaining ribs or vanes 114 of the valve member 108 such that the spring biases the valve member 108 to the left in FIG. 4 and maintains it in an open position during normal operation. The moveable valve member 108 includes a sealing head 110 that is adapted to seal against a generally conical valve seat 118 formed in the flange 90, as will be described. Under normal operating conditions, the valve is configured to permit flow into the pressure vessel through the valve 80 from external piping, such as makeup line 14 shown in FIG. 1, with the spring 112 and pressure of the fluid flowing into the pressure vessel 82 acting to maintain the valve member 108 in the open position. In this open position, the ribs or vanes 113, 114 are spaced apart or have fluid passageways so that fluid can flow into the pressure vessel via the central passageway 98 and the thermal sleeve 86. Should the pressure differential (in the outward direction) across the valve 80 exceed the spring bias applied to the valve member 108, such as when a break in the external piping is experienced (or when pressure inside the vessel 82 increases), the pressure in the pressure vessel 82 will act to compress the spring 112 and the valve member 108 will shift to the right from its position in FIG. 4 and seal against valve seat 118. This effectively seals the penetration through pressure vessel wall 82 in the event of a LOCA, and the valve will generally remain in the closed position until the pressure differential that resulted in the closing of the valve is mitigated. It will further be appreciated that the illustrated valve can also accommodate fluid flowing out of the pressure vessel 82 through the valve 80, such as letdown flow flowing into letdown line 16. In such a configuration, the spring bias maintains the valve member in the open position against the pressure of fluid flowing out of the pressure vessel 82. A sudden increase in pressure within the pressure vessel 82, or a drop in pressure of fluid in the letdown line (due to a break, for example) such that the pressure differential in the outward direction exceeds a closure threshold will result in the valve member 108 shifting to the closed position. Various springs can be used to provide a valve with desired operating characteristics. For example, in some applications a relative high bias open force may be desired, and a very stiff spring can be utilized to achieve the desired bias. The thermal sleeve 86 provides protection against thermal shock, and is advantageous for the isolation valve protecting the make-up line 14. On the other hand, thermal shock to the nuclear reactor is less likely to occur in the case of the let-down line 16. Accordingly, in some embodiments the thermal sleeve is omitted. In such cases, the inner wall of the bore 88 extending through the vessel wall 82 suitably serves as the anchor for the isolation valve. Alternatively, a sleeve structurally similar to the thermal sleeve 86 may be provided, but made of thermally conductive material and/or without any gap between the sleeve and the bore 88. It should also be noted that the valve seat 118 is a surface of the flange 90, and accordingly proper sealing of the isolation valve is not dependent upon the structural strength or integrity of the sleeve 86. In some embodiments, it may be desired to provide additional closure force to assist and/or ensure closure of the valve. For example, with reference back to FIG. 3, an electrical, pneumatic or hydraulic actuator piston P (shown in phantom) can be connected with the end of the rod 64. When working fluid is injected into the actuator piston P via actuation line A, the actuator piston acts via the rod 64 to actively pull the piston 38 into closure against the valve seat 42. A solenoid with electrical actuation could be substituted for the actuator piston P and fluid actuation line A. As another option, a latch disposed on the rod 64 can engage a locking mechanism (features not shown) when piston 38 moves to the closed position so as to lock the piston in the closed position. The locking mechanism can include a manual or electrically actuated release so that the isolation valve only re-opens when the operator activates the release. This arrangement ensures that the isolation valve cannot re-open prematurely (that is, before the operator intends for it to reopen). The isolation valves of FIGS. 2-4 provide bidirectional operation, and only close upon an outward pressure differential greater than a threshold value. Such isolation valves can be used for both makeup lines 14 and letdown lines 16. However, if the vessel penetration is intended to support only unidirectional flow into the pressure vessel, then the valve can modified accordingly. With reference to FIGS. 5-6, another isolation valve embodiment includes two valves 80, 80a aligned in series, wherein the inner valve 80 is located inside wall of the pressure vessel and the outer valve 80a is located inside a wall forging 72 that is external to the pressure vessel 10 such that it may be bolted to the pressure vessel 10. The disclosed isolation valves passively isolate vessel penetrations that are in fluid communication with the reactor coolant in the pressure vessel in the event of a pressure rise inside the pressure vessel. As shown in FIG. 1, these isolation valves are suitably used on makeup and letdown lines. Additionally, they may find application in protecting other vessel penetrations, such as the return line of an emergency condenser. Because the disclosed isolation valves are located inside the pressure vessel wall or inside a welded vessel penetration flange or in a flange assembly, they are failsafe against pipe breakages. (As previously noted, in the embodiment of FIGS. 2 and 3 although the biasing elements 56, 58 are outside the pressure vessel and flange assembly the valve components, e.g. piston 38 and valve seat 42, would continue to operate to provide failsafe operation even if the biasing elements 56, 58 are broken off). Although not illustrated, in the embodiment of FIG. 4 or FIG. 5 the flange 90 may optionally be a spool flange enabling a flanged connection of an external component to the flange 90. In this case, there is no external piping between the external component and the vessel penetration, and the vessel penetration is protected by the isolation valve. The disclosed vessel isolation valves are well-suited for use in conjunction with protecting a vessel penetration in a nuclear reactor pressure vessel. However, the disclosed vessel isolation valves are more generally applicable to protecting a vessel penetration in a pressure vessel generally, i.e. in a pressure vessel for an application other than housing a nuclear reactor. The preferred embodiments have been illustrated and described. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the invention be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
	description	As can be seen in FIG. 1, the storage and dispatch container consists of a main body 1 with a capillary tube 8 for the uptake of the radiation sources 15. The radiation sources 15 (cylindrical tube sections) are arranged end-to-end in a quartz glass capillary tube 8 which is enveloped by the main body of the container for reasons of radiation safety and visibility. This part is fully symmetrical apart from an appropriate mark in the form of a groove on the internal diameter of the acrylic glass main body 1 to show the level of contents. Storage and transport of the radiation sources 15 fundamentally takes place with the main axis in a vertical position. The lower end (standing surface) of this tube-in-tube combination is closed by a cylindrical lower end-piece 2 made of aluminum. The internal tubular section of the glass capillary tube 8 continues eccentrically with a smaller diameter inside this lower end-piece 2 and finishes in a commercially available fluid-medium connection 4 (quick coupling) by means of which catheters, syringes or similar items may be connected. Suitable transport media, air for example, can be introduced via this medium connection 4 in order to expel the radiation sources 15 out of the container. The lower end-piece 2 is attached to the main body 1 with two screws 6. The opposite end of the tube-in-tube combination is also closed by a cylindrical upper end-piece 3 made of aluminum. The internal diameter of the glass capillary tube 8 continues concentrically inside it. The said tubular section serves the input and output of the radiation sources 15. This tube is closed by a plunger 10 which is self-actuated by the force of the compression spring 11 and can only be opened using a corresponding counterpart, here the adapter 16. The opening is achieved by a wedge effect. The plunger 10 has the lateral effect of a slide valve and is guided by a bush. A clamping ring 9 secures the spring 11 and the plunger 10 against loss. This end-piece is also attached to the main body 1 with two screws 7. Another possibility of connecting the upper and lower end-pieces 3, 2 to the main body 1 consists of direct screwing/gluing to the main body 1. The screws 6 and 7 then become redundant. The two sealing rings 5 hold the quartz glass capillary tube 8 firmly between the upper and lower end-pieces 3 and 2 respectively. A cylindrical closure cap 13 protects the accurately drilled channel in the upper end-piece 3 from contamination. The said cap is pressed against the upper end-piece 3 using a ball catch 14. The following is a description of the input/output of the radiation sources 15 in the storage and dispatch container using an adapter as shown in FIG. 2. The storage and dispatch container with its accurately broached channel is pushed onto the neck 17 of the adapter (against the resistance of the seal) after removal of the closure cap 13. The plunger 10 is moved during this process, thus allowing free access to the input channel. A precondition for this is that the slide valve 18 is set at xe2x80x9copenxe2x80x9d (prior to connection). Held like this by an expedient device, the slide valve 18 can be moved to the closed position (safe) by hand or other contrivance. The chamfered edge of the oblong hole in the slide valve 18 is pressed against the edge of the upper end-piece 3 in this case, as shown in FIG. 3, thus holding the container pressed against the neck 17. The input channel is opened in true alignment in this way. Radiation sources can be conveyed into the storage and dispatch container by installing a catheter 19 on the headpiece 16 of an adapter using a catheter-adapter 20 and by using a transport medium, air for example. The container can be unloaded under the precondition that a suitable transport medium is attached to the medium connection 4 of the storage and dispatch container and that a corresponding collection container is located at the end of the catheter 19. The container can be dismantled to its component parts and cleaned so that it can be used again after exchanging the xe2x80x9cradiation damagedxe2x80x9d parts. The container can be utilized for beta-emitting radiation sources. The said container can also be used for storage and dispatch of gamma-emitters of different photon energy if lead acrylic glass, for example, is used as the material of the main body 1, or for changing the wall thickness of the main body 1 and/or the capillary tube 8. As can be seen in FIG. 3, The locking and opening device consists of a cylindrical headpiece 16 and the cover 22 which is designed as a round metal washer. The headpiece 16 and cover 22 are joined together with screws 21. A slide valve 18 embedded in the headpiece 16 runs between headpiece 16 and cover 22. The slide valve 18 projects from opposite sides of the headpiece 16/cover 22 so that it can be pushed back and forth by the wings 18a and 18b. The slide valve 18 possesses a cylindrical pin acting as the cut-off needle 26 which projects into the side of the input/output channel 23 of the neck 17 in the opened condition of the said device thus blocking the input/output channel 23. All three designated parts, the headpiece 16, slide valve 18 and cover 22, possess a centralized opening designed as a drill hole which accommodates the opening of the correspondingly designed container. The slide valve is designed in such a way that the said drill hole is oblong and tapers somewhat. This taper is chamfered in the direction of the headpiece 16. The locking and opening device is intended for operation with the axis in the vertical direction. The neck 17 with the input/output channel 23 for radiation sources is anchored in the headpiece 16. The neck 17 is an cylindrical alignment insert which can be introduced into a correspondingly aligned socket of the container thus providing a truly aligned connection to the input/output channel 23 of the container. In addition to the input/output channel 23 in the center, the neck 17 also possesses four flutes in the main axis direction in order to counteract the suction effect of coupling and uncoupling as well as a transverse drilling in the upper part to accommodate the cut-off needle 26. The headpiece also possesses the insertion opening 24 for catheter adapter 20 of the catheter tube through which the radioactive radiation sources are fed in or out. The said catheter adapter 20 is secured with a set screw. The loading and unloading process is described in the following. The container has to be pushed onto the neck 17 in order to fix the container in the locking and opening device as shown in FIG. 4. A lock on the container is self-actuated and moved during this process, thus allowing free access to the input/output channel 23. A precondition for this is that the slide valve 18 is set in the position xe2x80x9cstation openxe2x80x9d as shown in FIG. 5. The slide valve 18 can now be moved to the position xe2x80x9cstation closedxe2x80x9d. The cut-off needle 26 is pulled back at the same time in this process and allows free access to the input/output channel 23 in neck 17. The previously described chamfered edge of the oblong hole in the slide valve 18 now presses against an edge of the container, thus keeping the latter pressed under tension against the neck 17. The input/output channel 23 is opened with true alignment. Provided a suitable transport medium is connected and the catheter 13 is attached by its catheter adapter 20 to the headpiece 16, the radioactive radiation sources can now be conveyed into or out of the said container. The invention is not confined to the exemplary embodiments shown here. On the contrary, it is possible to achieve other variants of the embodiments by combination and modification of the designated means and features without departing from the framework of the invention.
050646036	abstract	A hydroball string sensing system for a nuclear reactor that includes stainless tubes positioned to guide hydroball strings into and out of the nuclear reactor core. A sensor such as an ultrasonic transducer transmitter and receiver is positioned outside of the nuclear reactor core and adjacent to the tube. The presence of an object such a bullet member positioned at an end a hydroball string, or any one of the hydroballs interrupts the transmission of ultrasound from the transmitter to the receiver. Alternatively, if the bullet member and hydroballs include a ferritic material, either a Hall effect sensor or other magnetic field sensors such as a magnetic field rate of change sensor can be used to detect the location and position of a hydroball string. Placing two sensors along the tube with a known distance between the sensors enables the velocity of a hydroball string to be determined. This determined velocity can be used to control the flow rate of a fluid within the tube so as to control the velocity of the hydroball string.
052251462	description	DETAILED DESCRIPTION OF THE INVENTION FIG. 1 illustrates an electron injection scheme for controlling transport in a tokamak plasma. An electron injector 10 is shown external to a tokamak plasma 12. The plasma has a toroidal magnetic field B.sub.T. Preferably, the injector 10 is placed where the natural grad-B drift direction is radially inward. This would either be above or below the plasma 12 depending on the direction of B.sub.T. For purposes of illustration, FIG. 1 shows the injector 10 below the plasma. Electrons are emitted from a heated cathode 20. An electro cyclotron heating (ECH) waveguide cavity 16 has an acceleration region 17 adjacent to the cathode for accelerating the electrons by radio frequency waves at the electron cyclotron frequency. Referring to FIG. 1a, ripple or bending magnets 18 are locally placed around the torus and provide a ripple field region in the plasma. The cathode 20 is connected to power source 19. The electrons are injected into the plasma and then allowed to drift vertically, by means of the grad-B drift, into the region of field ripple. The field created by the bending magnets is a relatively small perturbation to the magnetic field to cause the electrons to be trapped and drift radially inward into the center of the plasma. This charges the interior of the plasma negative and thereby creates a radial electric field at the edge of the plasma. The arrangement provides a means of biasing large tokamak plasmas without the insertion of material objects, and a way of attaining H-mode regime with substantially lower applied power. A detailed view of the cathode 20 is illustrated in FIG. 2. The cathode includes a carbon heater 22 surrounded by tantalum shields 24, and inside tantalum shields 24a. The heater and tantalum shields are supported by current feed and support tubes 26. Preferably, the tubes 26 are coaxial copper tubes for supplying a current feed as well as providing for water flow. The carbon heater 22 is also attached at one end to copper mounting blocks 24a. Adjacent to the carbon heater 22 at an end opposite the mounting blocks is an electron emitting faceplate 28 of LaB.sub.6 coated on molybdenum or tungsten. In accordance with the above description, a method for creating a radial field at the edge of a plasma of a tokamak includes providing a ripple field region in the plasma by the localized placement of a plurality of bending or ripple magnets 18 around the torus of the tokamak. Electrons having a predominantly perpendicular energy with respect to the toroidal magnetic field direction B.sub.T, are externally or non-invasively injected into the ripple field region and are trapped. The plasma center is negatively charged by allowing the electrons to grad-B drift vertically toward the plasma interior until they are detrapped, thereby creating a radial electric field at the edge of the plasma. The electron injector 10 described is capable of injecting approximately 20A of electron current with electrons having low KeV energy and a perpendicular to parallel energy ratio (v.sub..perp. /v.sub..vertline.) of greater than 1. For trapping the electrons it is also necessary that: EQU v.sub..perp. /v.sub.51 .gtoreq.(2.delta.).sup.1/2 (1) where .delta. is the ripple fraction. As an example, if v.sub..perp. /v.sub..vertline. is .gtoreq. 10, then the electron becomes detrapped when .delta..ltoreq.0.005. A cathode having electro cyclotron heating as described would obtain electrons with v.sub..perp. /v.sub..vertline. >>1. The radial penetration distance of injected electrons, L, can be controlled by adjusting the injected electron energy: EQU L=V.sub.D /.nu..sub.eff =40E.sup.2.5 (2.delta.).sup.0.5 (RBn.sub.e).sup.-1 (2) where L is expressed in centimeters (cm); E in KeV; R in meters (m); B in Teslas (T); n.sub.e is (10.sup.12 cm.sup.-3), and: EQU .nu..sub.eff sec.sup.-1 =2.5.times.10.sup.3 n.sub.e E.sup.-1.5 (2.delta.).sup.-0.5 (3) and further: EQU V.sub.D =10.sup.5 E(RB).sup.-1 (4) where V.sub.D is in cm/sec. For a typical tokamak fusion test reactor (TFTR) having parameters of R.apprxeq.2.7, B.apprxeq.5, n.sub.e .apprxeq.3, .delta..apprxeq.0.02, and E=5, the expected penetration distance, L, is 11 cm. The required injection current is modest (on the order of 10A), even for large tokamak plasmas. The minimum required injected current is determined by the leakage radial current. Taylor et. al gives an expression of the leakage radial current density from the force balance equation as: EQU J.sub.r B.sub..phi. /c=n.sub.i m.sub.i cE.sub.r /(B.sub..phi. .tau..sub.p) (5) where .tau..sub.pp is the momentum damping time which is thought to be of the order of ion-ion collision time (T. H. Stix, Phys. Fluids 16, 1260 (1973)). Integrating equation 5 over the surface, the total radial current obtained is: EQU I.sub.r =4.pi..sup.2 aRn.sub.i m.sub.i c.sup.2 E.sub.r B.sub..phi..sup.-2 .tau..sub.p.sup.-1 (6) Assuming .tau..sub.p to be the ion-ion collision frequency, one obtains: EQU I.sub.r (A)=10aR.mu.n.sub.e.sup.2 E.sub.r B.sub..phi..sup.-2 T.sub.i.sup.-1.5 (7) where a is in meters, R is in meters, n.sub.e is 10.sup.12 cm.sup.-3, E.sub.r is 100 V/cm, B is in Teslas, and R.sub.i is 10 eV. As an example, in terms of the above units, on the Continuous current Tokamak (CCT) at UCLA, a=0.3, R=1.5, .mu.=1, n.sub.3 =1, E.sub.r =2, B.sub..phi. =0.3, and T.sub.i =3, the radial current is about 20 amperes, which is very close the observed required injected current to maintain the high confinement mode in the CCT. For the TFTR, a=0.8, R=2.7, .mu.=2.7, .mu..ltoreq.2, n.sub.3 =3, E.sub.r =5, B.sub..phi. =5, and R.sub.i =30, the radial current is 0.47A, which is relatively small. For CIT (Compact Ignition Takamak) parameters, a=0.6.times. 1.4, R=2.1, .mu.=2.5, n.sub.3 =20, E.sub.r =5, B.sub. .phi. =11, and T.sub.i = 30, and the I.sub.r =4.4A, which is still quite small. Thus, the CIT plasma can be induced to go into the high mode with less than 100 KW of injected power. There has thus been shown na electron injection scheme for controlling transport in a tokamak plasma. Electrons with predominantly perpendicular energy are injected into a ripple field region created by a group of localized poloidal field bending magnets. The trapped electrons then grad-B drift vertically toward the plasma interior until they are detrapped, charging the plasma negative. Calculations indicate that the highly perpendicular velocity electrons can remain stable against kinetic instabilities int he regime of interest for takamak experiments. The penetration distance can be controlled by controlling the "ripple mirror ratio", the energy of the injected electrons, and their v.sub..perp. /v.sub..vertline. ratio. In this scheme, the poloidal torque due to the injected radial current is taken by the magnets and not by the plasma. Injection is accomplished by the flat cathode containing an ECH cavity to pump electrons to high v.sub..perp.. The foregoing description of a preferred embodiment of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The embodiment was chosen and described to best explain the principles of the invention and its practical application and thereby enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto.
	description	This application is a continuation-in-part application of application Ser. No. 11/119,255 filed Apr. 29, 2005, now U.S. Pat. No. 7,440,863, which is incorporated herein by reference in its entirety and to which application we claim priority under 35 USC §120. Qualification of instruments for regulated markets has traditionally followed one of two models: paper-based protocols that are run on instruments using the native controllers of the respective instruments; and external calculations or qualification routines that are embedded into the controlling softwares of the instruments, respectively. Some efforts at automated data collection have required that an alternative data path be employed for the data collection while still controlling the instrument using its native controller. Examples of proprietary embedded software suites include Cerity NDS (Agilent Technologies, Inc. for chemical/pharmaceutical quality assurance and quality control, and Empower CDS (based on Waters Millenium software, Waters, Inc. These software suites are limited to the suite of instruments that they can control. Thus, even though these suites are proficient for producing data and results for qualification/quality assurance tasks for the particular instruments that they control, such suites cannot provide standardization of the data types that are processed, nor calculations across controller platforms. Further, data is maintained in a proprietary format that requires the collecting data system to be present and functioning for viewing and reprocessing any data used/outputted by these systems. Recently, an integrated single source of data collection and storage, EZChrom Elite, was introduced by Scientific Software Inc. While offering a relatively large driver set, this solution is still limited by the available drivers that are provided with the solution Further, all of the current solutions, including those mentioned above, as applied to instrument qualification, require decoupling of the native system that controls the instrument to be qualified, in one fashion or another. It would be desirable to provide a solution capable of incorporating data from different instruments, as well as from different manufacturers, to compile reports thereon. It would be further desirable that such a solution provides standardization among various data types so that one platform can be readily used to generate reports using data generated from instruments having different platforms, and/or still other instruments that aren't included with any established platforms. Accordingly, there is a need for solutions that are generally applicable for use with data generated/collected by instruments from most, if not all manufacturers, to readily prepare reports therefrom and/or otherwise manipulate the data as needed Methods, systems and computer readable media for compliance testing at least one of instrumentation and software are provided for: inputting data from at least one analytical instrument or software performing one or more calculations on the data to produce one or more outputs; and selecting from the one or more outputs to populate a final report; wherein the one or more outputs are standardized and are directly comparable to outputs resultant from carrying out the method carried on another set of one or more other analytical instruments, irrespective of manufacturer or model of the other analytical instruments. Methods, systems and computer readable media may compare at least one of the outputs to first and second test limits, and report compliance status of the at least one output relative to the first test limit and to the second test limit. Methods, systems and computer readable media are provided for compliance testing at least one of instrumentation and software, by inputting data from at least one analytical instrument or software; performing one or more calculations on the inputted data to produce one or more outputs; comparing at least one of the outputs to first and second test limits; and reporting compliance status of the at least one output relative to the first test limit and to the second test limit. Methods, systems and computer readable media are provided for compliance testing at least one of instrumentation and software, to display a test protocol form on a user interface and prompt a user to input information regarding a test for qualifying a result of a test; prompt at least one instrument or software associated with an instrument to initiate the test protocol in response to an input by the user into the test protocol displayed on the user interface, or results from another instrument in response to a test protocol run on the another instrument; automatically calculate results of the test protocol run on the at least one instrument; and output status of the results as determined by at least one set of dual test limits. A system for standardizing characterizations of at least one of analytical hardware and controlling software during compliance testing is provided to include: a data reduction engine configured to reduce outputted by an analytical or other instrument; a calculation engine configured to perform at least one calculation on at least one of the data outputted by an analytical or other instrument and the reduced data to produce one or more outputs required for a set of predefined criteria; and interactive forms providing procedural information including calculation instructions. These and other advantages and features of the invention will become apparent to those persons skilled in the art upon reading the details of the methods, systems and computer readable media as more fully described below. Before the present systems, methods and computer readable media are described, it is to be understood that this invention is not limited to particular hardware, software, formats or media described, as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting, since the scope of the present invention will be limited only by the appended claims. Where a range of values is provided, it is understood that each intervening value, to the tenth of the unit of the lower limit unless the context clearly dictates otherwise, between the upper and lower limits of that range is also specifically disclosed. Each smaller range between any stated value or intervening value in a stated range and any other stated or intervening value in that stated range is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range, and each range where either, neither or both limits are included in the smaller ranges is also encompassed within the invention, subject to any specifically excluded limit in the stated range. Where the stated range includes one or both of the limits, ranges excluding either or both of those included limits are also included in the invention. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, the preferred methods and materials are now described. All publications mentioned herein are incorporated herein by reference to disclose and describe the methods and/or materials in connection with which the publications are cited. It must be noted that as used herein and in the appended claims, the singular forms “a”, “and”, and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a limit” includes a plurality of such limits and reference to “the form” includes reference to one or more forms and equivalents thereof known to those skilled in the art, and so forth. The publications discussed herein are provided solely for their disclosure prior to the filing date of the present application. Nothing herein is to be construed as an admission that the present invention is not entitled to antedate such publication by virtue of prior invention. Further, the dates of publication provided may be different from the actual publication dates which may need to be independently confirmed. A “platform” as used herein refers to a support infrastructure for acceptance and coordination of tools and applications required to perform a series of related, but diverse tasks. An “enterprise content manager” refers to a system, scalable to enterprise levels, composed of various hardware and software elements that support the secure collection, indexing and storage of electronic objects. Disclosed herein are methods, systems and computer readable media for processing data outputted by analytical instruments in a standardized manner so that results of processing are directly comparable with results from processing data outputted by other instruments, regardless of model or manufacturer. Methods, tools and computer readable media for generating, transmitting and storing forms specific for a user's needs are provided, including, but not limited to compliance validation forms. Systems include computers and associated hardware that may be connectable to a network (for internet or intranet use) that can execute rules for a selected form (e.g., one non-limiting example is a form suitable for submission to a regulatory agency such as the FDA). In one embodiment, a system is provided to perform analytical hardware qualifications. Calculations may be performed to answer a series of questions relating to one or more performance tests designed to determine compliance of an analytical instrument and/or software under consideration with a set of predefined criteria. Such predefined criteria may be criteria defined for regulated industries. For example, “predefined criteria” include, but are not limited to regulations set forth in the Food, Drug, and Cosmetic Act. Predefined criteria are limits and criteria that represent best practices and manufacturers' specifications relating to instrument operation and performance. Compliance to these acceptance criteria provides documented evidence of a device's operation within expectation of intended use. Such compliance is required by law and is listed in the Code of Federal Regulations under headings Part 210, 211, 820, 58, and 21-Part 11 as well as other such regulations and guidance as applies. Optionally, criteria such as limits may be set according to a user's needs, such as when dual limits, are provided, for example. Forms may be used as built-in records to store data as it occurs, lending to use of the forms for tracking/audit trails. The forms are further useable as a basis for generating reports in a variety of formats. However, as reports are changed, the underlying processes (e.g., the forms containing the data from which the reports are generated) stay the same. Basic universal forms stay the same, while the data they contain can be used to report in many different ways. The forms may be provided to a user in a “wizard-type” environment (i.e., as a “wizard-type” interface), wherein the user is prompted for simple tasks, the response to which are incorporated into a much larger data product. In this way the user only has to deal with simple, single item tasks, one-at-a time. An enterprise content manager (ECM) may be employed to provide a secure platform to manage all data storage, metadata extraction and archival of data. Alternatively, the system may operate independent of an enterprise content manager to perform data reduction, calculations, and output results, as well as other forms-based functions as described herein. One non-limiting example of an ECM that may be employed is a Cerity ECM, available from Agilent Technologies Inc. Since an ECM is an enterprise system, it also provides scalability to the present system. Referring to FIG. 1, data is inputted to the system in its native format at event 110, for initial conversion to a technology neutral format (event 120) so that all further processing is with respect to data that is all in the same format, regardless of which instrument was used to originally output the data in its native format. Data conversion may be performed when the system is associated with an ECM content manager, by the ECM content manager. Alternatively, data may be provided to the system that is already in a technology neutral format, as for example, when an instrument owner converts the outputted instrument data to a technology neutral format, and then this converted data is directly inputted to the system. Under this option, the system does not perform events 110 and 120, as the data inputted is already in a technology neutral format. As another option, if data cannot be submitted to the system in a technology neutral format and an ECM is not employed, the analog data outputted by an instrument may be received by the system and then converted via an A/D converter to a digital signal to be inputted into the system. The digital signal may be provided in a technology neutral format, such as a .cdf format (e.g., AIA, AnDI, etc.) or proprietary formats such as: bxx, pts, raw, .ch or dat, for example. Data reduction may be performed at event 125 by a data reduction engine as described below, if needed. By performing calculations/further processing (event 130) on technology neutral formatted data or digital signals having been converted from the analog output of an instrument, with the present system, calculations are thereby standardized, so that results (event 140) are directly comparable between data produced by various instruments, models and manufacturers. The standardization is made possible by the system's ability to convert data from external sources into a technology neutral format, input of data that is already in a technology neutral format, or read proprietary data, which is then data reduced and calculated by common components. Further, this standardization may be applied to data sources manually, semi-automatically (requiring some manual application) or automatically, and such data may require data reduction, or may be in a ready-to-process form. In this way data that characterizes the operation of instrumentation or controlling data systems can be used for the purposes of qualification of said device irrespective of proprietary or native format. One non-limiting example of a technology neutral format that may be employed by the present system is referred to as Analytical Information Markup Language (AnIML, see http://animl.sourceforge.net/) which is an open source, XML-based standard for formatting analytical data. By converting all data to a technology neutral format, and then processing the converted data all according to the same protocols, results are generated that are standardized and directly comparable among results for different instruments which may be different models and/or made by different manufacturers. As noted, the computerized data system (CDS) that is in place for operating the instrument(s) to obtain the data on which a report is to be generated may be used as direct input to the system. Thus, original data collected for a report may be accomplished using the native controlling software (of the CDS) of the instrument(s) without the need to go through external analog to digital conversion or other manipulation. As noted, the data collected may alternatively be collected in analog form and A/D converted for input to the system. Original data, which may be preserved for possible reanalysis by the native CDS, may also be converted to an accepted technology-neutral format allowing the data to be submitted to a single reprocess and calculation engine for consistent reduction and processing. By using the native CDS, the present system may also make use of the drivers employed by the native CDS, thereby further facilitating the universal applicability of the present system to different types of instruments and to instruments having different standards/CDS's as a result of being produced by different manufacturers. Instructions may be instantiated as forms 200 (e.g., see FIG. 2) to provide procedural information, while also functioning as data repositories. Forms 200 may be constructed in many different ways and presented to have as many different appearances, some of which are dictated by the information to be displayed/stored and much of which may be flexibly designed. The instrument/process type as well as the required input to the form 200 dictates the content and appearance of form 200. FIG. 2 shows one example of a form 200 which is in no way meant to be limiting, as many different forms may be provided by the system. In FIG. 2, form 200 includes fields instructing the following data to be inserted and stored: Instrument Name 202; Other Name 204; Channel Description: Split-Splitless 206, Purged-Packed 208, Volatiles Inlet 210; Model Number 212; Serial Number 214; and License Certificate ID 216. Forms 200 may be run as an applications program interface (API) and, as such need not ever be even visualized by a user of the system when all data fields can be automatically identified from the technology neutral formatted data and/or native CDS and populated into form 200 to complete all data fields. Alternatively, or additionally, a user interface 250 may be provided to display one or more forms. In a case where automatic population of all required data is not possible, user interface 250 can display form 200 so that a user can interactively select an entry (as in the case of Model Number 212, shown in FIG. 2, where a drop down menu is provided from which the user can select the proper entry) or manually input an entry, such as by typing, cutting and pasting, scanning or some other alternative data entry mechanism that requires intervention on the part of the user. Further alternatively, the user interface 250 may be optionally used to enter all data required by a form, either as a result of user preference to do so, or because an instrument being considered is sufficiently old or unsophisticated, so as to lack a sophisticated enough software interface to supply some or all of the data automatically by interfacing with the present system. As another alternative, a user interface may display a test protocol that prompts the user to input information regarding results of a test. In some instances, the test may be automated, wherein the system may prompt one or more lab instruments to initiate a test protocol in response to one or more answers inputted into the user interface by the user in response to questions asked on an interactive form/test protocol, or in response to results from another instrument (e.g., in response to a test protocol designed for that instrument). The system may also provide a report detailing processes and/or instruments that do not comply with selected specifications (i.e., a protocol deviation form). The forms may be XML based forms that can be directly rendered to a final report (such as in pdf format, or other format suitable for paper documents, for example). Thus, for example, forms 200 may be displayed in pdf or some other document format on user interface 250 when part or all of them are to be interactively filled out by a user. As noted, part or all of forms 200 may be programmatically filled out from auto detection of calculation engines provided by the system. Forms 200 may be left in native XML format and thereby function as storage for the data that they contain. Forms 200 may be further rendered from the XML format to an HTML version for use with a browser. When used interactively, forms may be presented to a user according to need and thus, forms that apply only to the instrument(s) under test are presented, thereby reducing delivery complexity and error potential, while at the same time providing audit trails for tracking, since the forms may be saved, as noted above. By converting proprietary data into standardized data (i.e., data having a technology neutral format), the system may provide data in a standardized output form. Thus, inconsistent output from instruments can be converted to consistent input to an engine that can do calculations in a very predictable, standardized way, which is an important consideration for qualification and compliance reports. Once native data has been converted into technology neutrally formatted data, or, alternatively, after converting analog signals outputted from an instrument to digital signals, or after receiving digital output signals from an instrument, metadata may be created by data reduction engine 302 (FIG. 3) of the system 100 so that algorithms from the instrument's 10 system(s) do not need to be relied upon, and this further ensures standardization of results. For example, for application to chromatography, the present system does not rely upon the software 12 running the chromatography instrument 10 from which the raw data is generated to determine what is a peak in the data or where to define the location of that peak, as such determinations are made based upon calculations and algorithms run by the data reduction engine 302 of the present system. Data reduction engine 302 reads the data having been converted into technology neutrally formatted data, or otherwise, and converts this digital representation of an analog function into data representing features described/characterized by the data (e.g., peaks, noise, gradient steps, etc.). The same applies to other calculations, such as those determining and/or filtering noise levels, etc. Using this approach, consistent results are determined for data across the board, whether a particular type of instrument 10 was manufactured by one or another particular manufacturer, or whether the instrument 10 is a different model than another, both of which data is being processed from. As one example, signal data from a chromatography instrument 612, as inputted to system 100 by the native controlling software for the instrument is just a series of changing signals over time. Reduction engine 302 converts these signals (which may or may not have been converted to a technology neutral format into useable data, e.g., peak area, noise calculations, etc.—which can be fed to calculation engine 306—e.g., there are 5 peaks and those 5 peaks have peak areas of 2, 2.1, 1.9, 2 and 2 and the mean is X, with standard deviation of Y, etc. so that these values can be compared to an acceptance standard, or with like values calculated with regard to another instrument 612. Depending upon the instrument that has generated the data, a data reduction engine 302 may not even be needed. For example, a balance already outputs data that is reduced to numbers that are useable by calculation engine 306 and so this data does not need to be further reduced, although it may be converted to a technology neutral format. Further, other alternative reduction engines 302 may be included with the system 100 as part of a library that may be accessed for non-standard reduction requirements. By performing data reduction with a component of system 100, this separates reliability on each instrument's software for performing such functions. Accordingly, all data reduction is standardized across reports that are prepared by system 100, and performance is all standardized by evaluation by the same system. Further, since the data is standardized, only one method need be developed to produce a particular type of report based on the data, as opposed to the current need to create a method for each instrument that employs a different data type or format. Thus, calculation engine 306 can perform calculations based upon a single library 304 (e.g., series of calculations tailored to a specific type of report for a particular type of data reporting). For consistent raw data sets (i.e., technology neutrally formatted data) received by data reduction engine 302, these data sets can be properly manipulated with a single consistent method. Thus although the method for acquisition of data may vary depending upon the computer data system from which the data is being acquired, once that data has been converted to a technology neutral format, the back end processing is consistent (e.g., processing by data reduction and calculation engines, etc.). Library 304 typically contains a set of calculations for performance of the standardized tasks in the back end processing (e.g., calculation/identification of peaks; calculation of statistics describing the data, etc.). With respect to data reduction and calculation, the results may be standardized and independent of the originating data-system or controlled instrument, as noted above. Reports based on those results are fully customizable, as reports ranging from simple summary reports to traditional, fully described compliance protocols may be outputted. The library can be modified, typically added to, to increase functionality, but it does not have to be a different library based on the data system that the instrument used, contrary to what is currently required. Consequently, calls become consistent and calculations become reusable and portable. For example, a library may be created to calculate peak precision, signal-to-noise, etc., and library 304 may be built to accept only consistent input forms because the input format will always be the same, since the engine for extracting data (data reduction engine 302) will always be the same. Running processes in this way provides consistent metrics across all manufacturers, types and models of instrumentation. For example, peak detection and baseline evaluation can be performed as de facto standards against which all systems/instruments may be evaluated. Thus, such a library 304 is reusable and portable, being applicable to calculation of the defined data specifications based upon data inputted from the data reduction engine 302, and wherein data reduction engine 302 may be applied to data from any applicable instrument for which it makes sense to calculate the prescribed specifications, since the data from the instrument will have been converted to a technology neutral format that the data reduction engine 302 is configured to receive as input. The standardization of processing will advantageously reduce training requirements for operating personnel, since personnel will no longer need to be trained for operating with regard to each different piece of equipment, but can instead be trained to run the standardized processes. For example, under conditions prior to the present invention, it would not be unusual for an instrument (piece of hardware) 10 to be operating in various locations under multiple (e.g., three) different proprietary operating software platforms. For compliance purposes, it might then be necessary to replicate the compliance procedures as many times as there are multiple platforms. By providing the present system as built on an independent platform, it is not dependent upon the operating software of the particular instrument upon which reports are to be generated. In this way the system is readily adaptable to new/various hardwares as well as softwares, given the generic nature of the protocols. As noted, system 100 may further employ a calculation engine 306 to perform calculations on the reduced metadata set produced by data reduction engine 302 for formulating standardized results 308. Calculation engine 306 performs calculations on metadata in the reduced metadata set received from data reduction engine 302 as well as any calculations that may need to be performed on other data that has been converted to the technology-neutral format, as instructed by forms 200, such as for the performance of qualification services on analytical instruments as well as other instruments. As noted, forms 200 may act as instructions for processes carried out by calculation engine 306, as well as for data storage repositories of the results of these calculations. Forms 200 can contain any combination of input types including interactive manual input, information detected by software of system 100 and/or the CDS of the instrument being considered and/or calculated reduced data. Forms 200 may further include launch points for executables that perform detection, calculation, or any other function called for by the process. Forms 200 may be version controlled and stored as record of the data collection process leading to a resulting final report. In this way the stored versions of forms can serve as an audit trail from the time of initial collection of the data all the way through to the time of the issuance of the final report. When standardizing all data to a technology neutral format and creation of metadata from the same, calculations by calculation engine may be carried out by calls to a consistent and tested library, as the calculations are reusable and portable. In order to manage data storage, metadata extraction and archival of data, as well as compilation of final reports and other form management functions, system 100 may employ an enterprise content manager (ECM) 404, as noted earlier. ECM 404 may provide a secure platform on which to manage the functions described. FIG. 4 illustrates a flowchart of functions and processes that may be managed by ECM 404 via business process manager (BPM) 406. BPM 406 manages flow so that data storage and format conversion (to a technology neutral format) are carried out by ECM 404 at event 408, followed by reprocessing/data reduction by data reduction engine at event 410, functions of which were described above. Further calculations are carried out by calculation engine 306 at event 412, which may be based upon instructions contained in forms 200 and the data populated into form 200 may be recorded and stored in ECM 404 at event 414. The record forms 200 may then be data mined at event 416 by record mining engine 440 to extract specific items of data/metadata that are required to populate a final report. FIG. 5 illustrates data extraction from a form 200 to obtain information needed for preparing a report, wherein a portion of a record form 200 is shown from which a particular data entry 502 is located. Record mining engine 440 may employ toolsets for mining data, e.g., name-value pairs may be taken from forms 200 and calculation engine 306 may further extract those values needed by identifying such values based upon the names associated with the values in the name-value pairs. Data from a form 200 can be calculated and the resulting calculations may be returned to the same form 200 or to another form 200 as needed for purposes of organization, readability, clarity, etc. As shown, forms 200 actually do contain the information/data received from the software of the instrument being considered, and that data can be mined to fill out automated report applications or otherwise to fill out a final report 444. In this way, forms 200 act as a repository that can be mined in various ways—compliance, asset management, etc. Once a final report 444 is signed, however, the data that was mined to fill out the final report document 444 can no longer be changed, ensuring inviolable metadata, so that an effective audit trail is maintained. An automated report application (automated report generator) 442 may be optionally included, and if used, functions to automatically populate documents at event 418 which are then outputted as a customizable report 444 at event 420. Automated report generator 442 is an application that facilitates that construction of configuration-specific documents from a library of all possible configurations. Automated report generator 442 allows documents to be populated with content learned through many various mechanisms, such as the mechanisms that have populated forms 200. An analogy to one function of the automated report application 442 is with reference to an automobile and an automobile user's manual that accompanies the automobile. Because the owner will typically have many options from which to choose from, the owner's manual is typically written to describe each of these options. Thus, for example, if an owner has a particular type of sound system, but there are six different sound system options for the owner's car, in order to access information about the sound system, the owner will typically have to page through descriptions of all six sound systems options in the user's manual until the matching sound system is found. An automated report application for owner's manuals would prepare this user's manual based upon the options chosen by the owner, so that when the owner looked up the description of the sound system, only one sound system would be described in the owner's manual, i.e., the description for the sound system actually selected by the owner for his/her car. The automatically populated forms 200 as well as the final report 444 may be stored into ECM 404 when an ECM is employed, so that ECM 404 is the location of the initial collection, calculation, meta-data and final data, as well as audit trails. Thus, system 100 may include a relational database with tools such as data reduction engine 302, calculation engine 306, and record mining engine 440, for example, sitting on top of it. Reports 444 can take on any form, and may be selected by a user. For example, a report may be created in summary form or in full detail, with or without a logo, etc. While the reports 444 are customizable, the underlying forms 200 created by the system 100 do not change so that standardization is preserved. Auto-documentation feature 442 may be optionally provided, as noted above, whereby the user is provided with selectable choices, via user interface 250, to determine the format of the report 444 to be produced. Thus, depending upon the selection made, different groupings of metadata from the underlying forms 200 are selected and combined into a format of the final form selected. Audit trails may be automatically provided by the metadata stored as forms 200 by ECM 404, as alluded to above. Further BPM 406 may provide e-mail notification, scheduling and review, electronic signature functions, etc. Referring now to FIG. 6, a flow chart that further explains process flow by a system employing an ECM 404 and BPM 406 is shown. As noted above, a user interface may or may not be needed, which may depend upon the choice of the user, the types of instruments being reported upon, and/or whether the system is capable of fully automatically obtaining all information required to generate a final report. System control API's 602 are provided for running processes so that there is not a need to display the process on user interface 250. The business process manager (BPM) 406 permits flexible formatting of process. For example, the process can be changed just by changing/rearranging a flow chart similar to that which is shown in FIG. 6. For example, flow charts used may be flow charts produced by Microsoft Visio e.g., see http://office.microsoft.com/en-us/FX010857981033.aspx, or other alternative chart building software that allows flow charts to be readily modified interactively. Such chart building softwares provide a visual manifestation of a process implemented and controlled by BPM 406. As a simple example, if a current process flow of system 100 includes a process or subprocess defined by steps A>>B>>C>>, but the current user/client requires step C to be performed after step A and before step B, then the current process chart can be interactively rearranged, such as by dragging step C between steps A and B and dropping it there to result in a process/subprocess defined by the steps A>>C>>B. Accordingly, the system 100 provides a great amount of flexibility for customizing the process control, which is then managed by BPM 406 using forms-based process management 604 as was described earlier. The technology neutral design of system 100 allows any client's or manufacturer's data system (i.e., Instrument's Data System 606) to be fed into ECM 404. Accordingly, any type of instrument, model of instrument or manufacturer of an instrument may be included as instruments 612 from which data can be received by system 100. For example, Instrument 1 may be a liquid chromatography/gas chromatography instrument 612 produced by a first manufacturer, Instrument 2 may be a liquid chromatography/gas chromatography instrument 612 produced by a second manufacturer, Instrument 3 may be still another liquid chromatography/gas chromatography instrument 612 produced by a third manufacturer, Instrument 4 may be a mixed vendor system, Instrument 5 may be a refrigerator with an embedded microprocessor or other associated hardware/software configured to input data to system 100 (or alternatively, data from this instrument may be manually inputted via interface 250 if Instrument 5 is not sufficiently automated), and Instrument 6 may be a centrifuge, wherein the same considerations apply as described with regard to Instrument 5. A “mixed vendor system” refers to systems produced by more than one manufacturer/vendor. Examples of mixed vendor systems include, but are not limited to: a computer data system manufactured by a first vendor and controlling an instrument manufactured by a second vendor; a computer data system produced by a first vendor that controls instruments produced by second, third and fourth different vendors; or a computer data system produced by a first vendor and controlling a single instrument made up of components produced by different vendors, etc. As long as the associated computer data system can successfully drive the mixed vendor system, the present system can process the data in a manner as described. As noted above, if the instrument's data is proprietary data, the proprietary data may be converted to technology neutral formatted data, (e.g., AnIML, etc.) using data system control API's 602 (or, if provided in human readable form, the data may be added to the forms manually and included into qualification processing with any required calculations, or may be converted from an analog signal outputted by the instrument to a digital signal inputted to the system) and both the proprietary data and the converted (technology neutral, A/D converted, and/or manually inputted) data may be saved in ECM 404. The data can then be further processed by data reduction engine 302, calculation engine 306 and reporting engine 608. Reporting engine 608 requires at least one of a data mining application (e.g., record mining engine 440) or a middleware component configured to provide an input file to reporting engine 608 to correctly populate a report. Once final report 444 has been generated, BPM 406 can direct reviews and signatures electronically at event 610. The final report, both signed and unsigned may be stored in ECM 404. Further, all intermediate forms 200 and the data that they store may be stored in ECM 404 to maintain a complete audit trail, as was also discussed. All processing represented in FIG. 6 may be based on forms and the instructions contained therein. WYSIWYG (“what you see is what you get”) authoring capability may be provided by the forms designer application for designing forms 200. Secure data handling is ensured by ECM 404. Standardized results are the end product of these methods, providing a clear differentiator over anything that is currently available in the market. The data path that the instrument 612 uses is the same data path that system 100 uses for reports such as compliance. However, the calculations performed on the data for whatever report is to be produced, do not need to be performed on the instrument itself, nor does the instrument's software need to be employed for performing calculations. Advantageously system 100 provides everything that is needed for performing such calculations. This effectively reduces the native computer data system (CDS) to a controller and data acquirer. Such reduction provides checks on the interplay between the hardware and software of a system to be qualified at each qualification event without burdening the hardware qualification event with data reduction evaluation of the native CDS. This assures that the more frequent requirements for hardware qualification provide the maximum value with respect to CDS verification, without forcing extensive CDS evaluation. Further, the controlling system (CDS) need not be qualified for use in the qualifying of hardware, since it is not used for such purpose by system 100. Rather, system 100 performs calculations on the raw data produced by the instrument (after conversion to a technology neutral format, if necessary), thereby taking the instrument's controlling software out of the loop and effectively separating the instrument's hardware, from the associated software, so that the report can focus on the hardware, independent of qualifying the instrument's controlling software. The modularity provided by system 100 facilitates modular instrument qualification after repair. The process flow manager 406 may present forms specific to the tests associated with the requalification of a module. The resultant data can be associated with the module, stack and existing compliance documentation to requalify the module. Thus, if a module needs to be repaired, then that module can be requalified, rather than having to requalify the entire system, i.e., qualification may be done on a modular basis. BPM 406 may control the workflow from collection of data through approvals/signatures of final report 444, and may be tightly integrated into ECM 404. The entirety of processing may be web browser-based or terminal servers-based so that no footprint is imposed upon the user's qualified computer. In instances where ECM 404 has been incorporated into a customer's system, local interfaces (e.g., user interface 250) may be employed. Referring now to FIG. 7, a schematic representation of an embodiment of system 100 is shown for use in creating a compliance report for chromatographic instrumentation. System 100 is represented as interfacing with native CDS to receive data inputs. In this example, the equipment being reported on is mixed vendor equipment 612, in which case, any or all of the vendor's computer data systems 704 may be employed through which data is inputted to system 100. Typically, however, a common data system controller (CDS) is provided to control all of the mixed vendor modules, as noted above. Forms 200 (which may optionally be driven by BPM 406, in which case forms 200 may be presented to a user by placement into a user-specific inbox, e.g., BPM Inbox 706, that functions similarly to the inbox of an e-mail service) are presented to a user of system 100 for forming a compliance report. For example, simple instructions can be provided in a “wizard” like environment (i.e., where simple tasks are completed sequentially and interactively). Thus, if a message is placed in inbox 706 that instructs a simple task to be performed, once the task is performed or “Done”, then the next task can be emailed or placed into inbox 706. At event 708, whether or not BPM 406 is employed, a user, or manager assigning tasks to a user, may choose the type of test or qualification to be performed. In response to this choice system 100 may then run a template to call the correct forms to be completed for the chosen test. Configure stack 710 provides a configuration-specific template which determines the required tests, forms and instructions to be processed. Forms for Instruction 712 are one option for processing, herein these forms 200 associated with a qualification event may contain simple instructions for processing with no data entry potential. Forms for Acquisition Process 714 provide another option for processing according to forms associated with a qualification event in which forms 200 may describe the setup of the native data system to perform specific runs and acquire specific data from the instrument and/or software to be qualified. Those same forms 200 may provide controls for entry (which may be manual and/or automated) of the results obtained from the processes run with respect to the native computer data system to obtain the specific data. Forms for Manual Entry 716 are forms 200 in which manual entry may be made directly to. Alternatively, entry may be made to these forms 200 via an application supplied user interface when required by a system being tested. Manual data 718 refers to a further embodiment of forms 200 that may be created such that form elements are present to allow manual, interactive entry of data from an attendant user. Forms 200 may also be constructed as a mixed model where some elements of the forms 200 are automatically filled in when the data is available to the system. When data is not available to the system for automatically filling in the forms 200, such data can be interactively filled in (manually) by a user. Compliance auto detection engine 720 may be an applet very similar to calculation engine 306 that stores or accesses identifying characteristics regarding various types, manufacturers, etc. of equipment. So for example, where a form requests a model number and serial number of an instrument 612, rather than requiring a user to manually enter this information, autodetection engine 720 queries the software 704 associated with the piece of equipment 612 to obtain the required information and then automatically enters it into the form 200 from which the request originated. If autodetection engine 720 is unsuccessful in automatically retrieving some or all of the information that was queried for, system 100 leaves the entries for this information on the applicable forms 200 blank and presents the forms for manual completion in addition to the automatic generation (autodetected data 722) to whatever extent was possible. Data storage and format conversion of the inputted data may be performed by system 100 (optionally, by ECM 404 as controlled by BPM 406) in accordance with the instructions contained in forms 200 selected for processing the data, wherein forms 200 identify the particular data that is needed. In this example, data may be converted to AnIML formatting 724 or other common data form (CDF), such as AIA (Analytical Instrument Association) or ANDI (Analytical Data Interchange) format (typically annotated with .CDF extensions). When converting to AnIML, Native Data AnIML package 726 may be employed to provide/store the data in the AnIML format as well as in the native CDS format. Analog data from an instrument may be A/D converted into a standardized format 724′ for use by the system 100, such as AIA or Native EZC format or other compatible input format to reduction engine 302, for example. In any case, once the data is converted, data reduction engine 302, (whether integrated to ECM 404 or standalone) may perform reprocessing of the data in accordance with the needs of the final report to be generated, as instructed by the forms 200 that need to be filled out (and which may optionally be guided by BPM 406, as noted above). Reprocessing/data reduction calculations can be can be driven by API, so that no user interface is required (i.e., No-GUI Reprocess 728). Thus, data can be inputted directly from an instrument's operating software 704 to instrument 100 where it may be converted to a technology-neutral format and then fed directly to data reduction engine 302. The reduced/reprocessed data is forwarded to calculation engine 306 (in this example, calculations are performed for a compliance report, and engine 306 is referred to as a compliance engine) for further calculations that are instructed by forms 200. Calculation engine 306 may mine forms 200 that have been populated by the reprocessing by data reduction engine 302, or may obtain data from mining results based on matching names to name-value pairs as described above, perform the instructed calculations, and, together with the reprocessed data, output metadata 730, which is chromatographic metadata in this example. This processing may also be API driven, so that all processing may be carried out in the background, without interrupting a user for interactive input. However, even if all the automation cannot work as intended, (such as when an instrument lacks adequate software or other capability for automatically interacting with system 100, for example) then system 100 may launch user interface 250 to accept some interactive input from a user, under guidance of a standard operating procedure, so that the user can interactively choose information to be filled in. Even the calculation engine 306 is designed to work as an API, as noted. However, a user interface 250 may also be provided for calculation engine 306 to allow a user to use it as a custom calculator, for example, so that the same results can be manually calculated, through interface with a user, since the custom calculator uses the same engine 306 that the automated client uses. Any or all of the manual data 718, autodetected data 722 and metadata 730 may require some additional manual entry(ies) depending upon the particular instrument from which data is being obtained. Examples of metadata entries that may need to be entered manually include, but are not limited to results of data collected from a source other than the data source provided by the native CDS, such as readings from onboard sensors, readings from external measurement devices, etc. Forms 200 that contain the manual data 718, autodetected data 722 and metadata 730 are mined for the specific data required by the final report 444 to be created (such as by using record mining engine 440), and the mined data may be forwarded to an automated report generator application 442 that assembles the mined data into an automated report input file 732 which is forwarded to an unparsed master file 734, from which the automated report application renders the final document 440. Alternatively, an automated report application need not be implemented. For example, final reports 732′ may be embodied by completed forms 200 without the need to data mine such forms. Further alternatively, a final report may be compiled by mined data that is simply assembled and attached to the forms 200 containing metadata. Everything between the raw data (e.g., original data received from an instrument or instrumentation software) and the final reported values is considered metadata. Metadata may be raw data or mined data or a combination thereof as it is used to populate a form. Some pre-final data may already be provided on a form while additional pre-final data may need to be added by the process. The data on the forms 200 can all be considered metadata in the sense that it is used to create the final report data so it qualifies as data about the final report data. In instances wherein BPM 406 is employed, BPM 406 may then forward the final document, such as via e-mail, for example, to have the final document (which may be in pdf format, as in the example shown in FIG. 7) signed. Alternatively, the final document may be manually forwarded by a user, such as by the user emailing or otherwise forwarding the final document. The final report cannot be modified by those reviewing it, but must be reprocessed by the system 100 if changes are to be made. The process flow for such a rerun or re-evaluation involves returning the process to the step that begins processing the information that is desired to be re-evaluated. However, if this is not done, then any changes will still be captured by system 100 (or by ECM 404, if used) through its automatic audit trails functionality. Further, BPM 406, together with ECM 404 may track the review process and store records of the same to maintain the chain of the audit trail. The final report 440 is thus a defensible piece for use in meeting compliance regulations. Forms 200 provide the basis for processing data by system 100. Wizard-like central data collection may be provided wherein either the automated client or a user are provided with simple tasks to complete by filling in the appropriate data, which may require a user to type in, scan in, select, or otherwise enter data, or which may require the automated client to query the instrument's software for the data which is then inputted to the form, or to perform calculations on select technology neutral data having been converted from the native data received from the software of the instrument, or other processing as instructed by the particular task presented by the form. In their most basic configuration, forms 200 are provided to generate a customer deliverable, typically a final report containing specifically requested or required data. Thus, forms 200 with standard defaults may be provided to automatically generate such a final report. Further, forms 200 stored in ECM 404 may be configured to function to provide an audit trail (such as by storing versions of the forms as they are completed, together with data and time stamp, for example). Further, forms 200 may be configured to contain instructions for all processing by system 100. For example, certain forms 200 may contain specific instructions for calculations to be performed by calculation engine 306. Thus, forms 200 can be interactively filled out by a user through user interface 250, and/or can be programmatically filled out by autodetection processes or calculation engines. Various combinations of forms 200, automation and custom reporting may constitute a final report by system 100. For example, forms 200 alone may be interactively filled out by a user to prepare a final report. Using ECM 404 together with forms 200, forms 200 along with the final report 444 may be centrally stored and provide an audit trail for support of the final product. By adding the automated calculation engines, such as data reduction engine 302, calculation engine 306 and records mining engine 440, for example, processing may be fully automated to provide a final report, if only according to a defaulted form of the final report 444. Adding the autodoumentation application 442 provides further flexibility, whereby a final report 444 can be customized. Note also, that the modules need not be combined as described, or in the order as described. For example, forms 200 may be combined only with automated report application 442, so that a final report 444 generated from manual inputs to forms 200 may be customized using the automated report application 442. Further, a hierarchy of forms 200 may be provided for more efficient completion of forms 200 during processing. For example, a master form may be set up to feed other process forms. A master form generally contains information that is globally the same with respect to all process forms that it feeds. Accordingly, this permits global information to be filled out only once, after which is automatically appears in all of the subordinate forms 200 fed by that master form 200. Different types of master forms 200 may also be created. For example, a qualification master form 200 may contain global information such as customer information (address, names, etc.), instruments that a qualification will be covering, and/or acceptance limits for instrument categories. An instrument configuration master form 200 may contain a named configuration mapped to configuration details (e.g., a stack of instruments 612) and/or override limits for specific equipment needs. A stack, for example, may include all of one type of instrument, different vendors' instruments, or any combination of instruments, as the complexity of the stack can be programmed into an instrument configuration master form 200. Instrument configuration master forms 200 may be limited to only those instruments and vendors that are configuration master approved, to prevent a user from arbitrarily attempting to add an instrument to an instrument configuration master form for which there is no procedure for processing. Using the methods and systems described herein, non-vendor specific instrument qualifications may be processed using a native controlling software of an instrument combined with a technology-neutral, standardized, post-collection data reduction and reporting model. Such processes may be provided by universally applicable, scalable, automated, secure and consistent platform for the development, and delivery of instrument qualification. Original data collected for the qualification may be accomplished using the native controlling software without the need to go through external analog to digital conversion or other manipulation. However, the system 100 is not precluded from using alternative data input methods, including, but not limited to data that has already been digitized; manual input of data, etc., as already noted above. Original data may be preserved for possible reanalysis by the native controlling software, and may also be converted to an accepted technology-neutral format allowing the data to be submitted to a single reprocess and calculation engine for consistent reduction and processing. Instructions may be instantiated as forms, which may provide procedural information as well as act as data repositories. Forms may be presented according to need and apply only to the instrument under test to reduce delivery complexity and error while providing audit trails for tracking. FIG. 8 shows an example of a form 200 that may be provided for qualifying equipment, and may be used for recording test specification and report definitions in making qualification protocols. Each protocol may contain tests, with set points and limits, required to be executed on any single instrument or named group of equipment. Although FIG. 8 shows an example of a form 200 for testing flow accuracy and precision of solvent flow rate in a liquid chromatography apparatus, other tests/forms that may be included in a qualification protocol for such a liquid chromatography apparatus include, but are not limited to: accuracy and stability of column temperature; wavelength accuracy; signal noise and drift; injection precision and carry over; response linearity; solvent gradient composition accuracy, stability and linearity; and sample temperature accuracy. Of course, qualification by the present system 100 and forms 200 are not limited to liquid chromatography apparatus, but may be applied to other instrumentation, softwares and hardwares, as indicated above. A default list of tests, set points and limits may be provided for each type of qualification and instrument that may be qualified by the system 100, using recommended tests. The default set of tests may be accepted by a user, or a user-selected set of tests, optionally with user selected settings can be used for a custom configured qualification procedure. While FIG. 8 is described with reference to a flow accuracy and precision test, it is noted that common features that apply to forms 200 for other quality tests are described here. The test name 222 is typically provided by the system, although, for custom-designed tests, form 200 may allow editing of the test name 222. A brief test description 224 may also be provided. Field 226 may be manipulated by the user to run the identified test (i.e., “Run”, as shown), or to omit running this test, by toggling the field to “Don't Run”, for example by selecting button 227 to visualize a drop down menu from which to select either “Run” or “Don't Run”. The customer reference field 228 allows the user to input a description tailored to the user's needs for easily identifying/describing the test that is being performed, wherein specific equipment tested may also be identified. Test settings 230 (such as flow rates, for this example) are typically preset by the system, but may be modified by a user for customized testing, and many other purposes, such as by selecting from a drop down menu of available settings when selection on button 231. FIG. 9 shows another example of a form 200 that may be provided for qualifying equipment, and may be used for recording test specification and report definitions in making qualification protocols, in which dual limit features are used for qualifying instruments according to their age or number of hours of use. In this example, the limits fro newly installed instruments have been chosen by the user to match the limits recommended 236 by the system/form 200, while a secondary set of limits 234 in this example have been chosen to be less stringent than the first set of limits 232 and are to be used for instruments that have been in operation for a year or more and for which it is generally accepted that a less stringent performance limit can be applied to account for normal wear and tear and mechanical degradation. Regardless of what the first 232 and second 234 limits are chosen to be by a user, the system recommended limits 236 are always provided in forms 200. For example, the recommended limits 236 provided may be provided as specifications typically found to meet international industry standards and regulatory expectations, in the judgment of the protocol developers. Dual test limits (i.e., a more stringent limit and a less stringent limit) may be provided for any or all tests performed. The forms 200 may have system recommended limits preset in both sets of limits, which are then modifiable by a user, as noted in the example of FIG. 9 above. In the example shown in FIG. 8, the user has maintained the system preset limits in limit set 234 and limits 232 have been modified to less stringent limits. The user specification second limit 232 for Flow Rate 1: Accuracy has been changed to a less stringent limit (i.e., ≧10.00%) than the corresponding limit 234, which in this case is left at the system recommended limit (i.e., ≧5.00%). The user may modify a limit by selecting the button 233 (or 235) corresponding to the limit to be modified, and selecting a value from a resulting drop down menu of values. Thus, a user may individually modify any single limit 232 or 234 to a value that is less stringent or more stringent than the corresponding limit 234 or 232 in that dual limit set for a particular test. In the example of FIG. 8, the user has set the user specification limits 232 for accuracy and precision to be less stringent and more stringent, respectively, than the recommended limits, with regard to Flow Rate 1. For Flow Rate 2, the user specified limits 2322 have been left equal to the recommended limits 234. The names 232N and 234N for each respective limit may also be user modifiable, to name the limits appropriately, as can be noted in the names that have been entered by the user in the example of FIG. 9. For example, terminology naming the limits (i.e., names 232N and 234N) can be modified by the user to match the corporate glossary, procedural requirement, or department preferences or practices. The operator fields 238 for the limits may also be user modifiable. For example, the user may select button 239 and select a “≦” operator or a “≧” operator. As another example of the use of dual limits, the user may want to make limits 232 more stringent than limit 234, so that if the instrument passes limit 234, but fails limit 232, the user is identified as such and knows that the instrument, in this case, passes the qualification, but may not meet internal standards. Or this may alert the user that the instrument, although currently passing, should be tested more frequently, as it may need recalibration and/or repair soon, since it failed the more stringent limit. In other instances, a user may want to set user limits 232 less stringently than the recommended limits 234, depending upon the user's needs. Thus, for example, if something less stringent than the system's recommended limit is still a useful or useable limit for the user's intended purpose, then the user may set limit 232 to be less stringent than recommended limit 234. Upon running a dual limit test, the resulting status of the equipment tested is outputted. Default status names provided by the system include “Pass”, “Pass recommended limit only”, and “Fail”, where “Pass” indicates the test result meets both of the set limits 232 and 234, “Pass recommended limit only” indicates that the test result mess the less stringent limit, but not the more stringent limit, and “Fail” indicates that the test result does not meet either limit. These status names may also be user-modifiable to any name or term desired. While the present invention has been described with reference to the specific embodiments thereof, it should be understood by those skilled in the art that various changes may be made and equivalents may be substituted without departing from the true spirit and scope of the invention. In addition, many modifications may be made to adapt a particular hardware, software, instrument, module, process, process step or steps, to the objective, spirit and scope of the present invention. All such modifications are intended to be within the scope of the claims appended hereto.
058621938	claims	1. A method for producing a radionuclide via a (n,.gamma.) Szilard-Chalmers reaction, the method comprising irradiating a target with neutrons in the presence of an oxidizing agent to form an irradiated mixture, the target comprising a metal target nuclide in the form of a metallic element or an inorganic metallic compound or salt, the irradiated mixture comprising (a) an oxidized product nuclide formed by reaction of the target nuclide with neutrons via a (n,.gamma.) reaction and with the oxidizing agent via an oxidation reaction, and (b) unreacted target nuclide which has not reacted with a neutron or with the oxidizing agent, controlling oxidation of target nuclide which has not reacted with a neutron, and separating the oxidized product nuclide from unreacted target nuclide. irradiating a target with neutrons in the presence of an oxidizing agent to form an irradiated mixture, the target comprising a metal target nuclide in the form of a metallic element or an inorganic metallic compound or salt, the irradiated mixture comprising (a) an oxidized product nuclide formed by reaction of the target nuclide with the neutrons and with the oxidizing agent and (b) unreacted target nuclide which has not reacted with a neutron or with the oxidizing agent, the amount of oxidizing agent present during irradiation ranging from a stoichiometric amount to about four times the stoichiometric amount required for the target nuclide to react with the oxidizing agent to form the oxidized product nuclide, and separating the oxidized product nuclide from unreacted target nuclide. irradiating a target with neutrons at a pressure which is less than atmospheric pressure and in the presence of an oxidizing agent to form an irradiated mixture, the target comprising a metal target nuclide in the form of a metallic element or an inorganic metallic compound or salt, the irradiated mixture comprising (a) an oxidized product nuclide formed by reaction of the target nuclide with the neutrons and with the oxidizing agent, and (b) unreacted target nuclide which has not reacted with a neutron or with the oxidizing agent, separating the oxidized product nuclide from unreacted target nuclide. irradiating a target with neutrons in the presence of an oxidizing agent to form an irradiated mixture, the target comprising a metal target nuclide in the form of a metallic element or an inorganic metallic compound or salt, the irradiated mixture comprising (a) an oxidized product nuclide formed by reaction of the target nuclide with the neutrons and with the oxidizing agent and (b) unreacted target nuclide which has not reacted with a neutron or with the oxidizing agent, cooling the target while the target is being irradiated, and separating the oxidized product nuclide from unreacted target nuclide. irradiating a target with neutrons in the presence of an oxidizing agent to form an irradiated mixture, the target comprising a metal target nuclide present in a target layer formed on the surface of a substrate, the target layer comprising a metallic element or an inorganic metallic compound or salt and having a projected thickness of not more than about 150 nm, the irradiated mixture comprising (a) an oxidized product nuclide formed by reaction of the metal target nuclide with the neutrons and with the oxidizing agent, and (b) unreacted target nuclide which has not reacted with a neutron or with the oxidizing agent, separating the oxidized product nuclide from unreacted target nuclide by a protocol which includes the step of exposing the oxidized product nuclides to a non-oxidizing solvent. preparing a target comprising a metal target nuclide in the form of a metallic element or an inorganic metallic compound or salt, allowing the prepared target to age for at least about 24 hours, irradiating the aged target with neutrons in the presence of an oxidizing agent to form an irradiated mixture, the irradiated mixture comprising (a) an oxidized product nuclide formed by reaction of the target nuclide with the neutrons and with the oxidizing agent, and (b) unreacted target nuclide which has not reacted with a neutron or with the oxidizing agent, and separating the oxidized product nuclide from unreacted target nuclide. preparing a target comprising a rhenium target nuclide, .sup.t Re, having an oxidation state of not more than .sup.+ 6 in the form of elemental rhenium or an inorganic rhenium compound or salt, where t is 185 for producing .sup.186 Re and t is 187 for producing .sup.188 Re, allowing the prepared target to age for at least about 24 hours, irradiating the aged target with neutrons at a pressure which is less than atmospheric pressure and in the presence of an oxidizing agent for at least about 1 hour to form an irradiated mixture, the irradiated mixture comprising (a) an oxidized product nuclide, .sup.p Re, formed by reaction of .sup.t Re with neutrons via a (n,.gamma.) reaction and with the oxidizing agent via an oxidation reaction, where p is 186 when t is 185 and where p is 188 when t is 187, and (b) unreacted target nuclide which has not reacted with a neutron or with the oxidizing agent, cooling the target while the target is being irradiated, and separating the oxidized product nuclide from unreacted target nuclide to form a product mixture, the product mixture being isotopically enriched in the product nuclide by a factor of at least about 1.5 relative to the irradiated mixture. 2. The method of claim 1 wherein the target comprises elemental rhenium or an inorganic rhenium compound or salt which includes a .sup.t Re target nuclide in an oxidation state of not more than +6, where t is 185 or 187, and the oxidized product nuclide is .sup.p ReO.sub.4.sup.-, where p is 186 when t is 185 and p is 188 when t is 187. 3. The method of claim 1 wherein the target consists essentially of elemental rhenium. 4. The method of claim 1 wherein the target comprises an inorganic rhenium compound or a salt thereof which includes a .sup.t Re target nuclide in an oxidation state of not more than +6. 5. The method of claim 1 wherein the target comprises a rhenium oxide or a salt thereof which includes a .sup.t Re target nuclide in an oxidation state of not more than +6. 6. The method of claim 1 wherein the target comprises a rhenium oxide or a salt thereof which includes a .sup.t Re target nuclide in an oxidation state of not more than +6, and either or both of a M-oxide or a M-hydroxide where M is a metal other than rhenium. 7. The method of claim 6 wherein M is selected from the group of metals consisting of tin, titanium and magnesium. 8. The method of claim 1 wherein the oxidizing agent is oxygen. 9. The method of claim 1 wherein oxidation of target nuclide which has not reacted with a neutron is controlled by controlling the amount of oxidizing agent available to react with the target nuclide. 10. The method of claim 1 wherein oxidation of target nuclide which has not reacted with a neutron is controlled by controlling the temperature of the target during irradiation. 11. The method of claim 1 wherein the oxidized product nuclide is separated from unreacted target nuclide by a protocol that includes exposing the oxidized product nuclide to a non-oxidizing solvent. 12. A method for producing a radionuclide via a (n,.gamma.) Szilard-Chalmers reaction, the method comprising 13. The method of claim 12 wherein the target comprises elemental rhenium or an inorganic rhenium compound or salt which includes a .sup.t Re target nuclide in an oxidation state of not more than +6, where t is 185 or 187, and the oxidized product nuclide is .sup.p ReO.sub.4.sup.-, where p is 186 when t is 185 and p is 188 when t is 187. 14. A method for producing a radionuclide via a (n,.gamma.) Szilard-Chalmers reaction, the method comprising 15. The method of claim 14 wherein the target comprises elemental rhenium or an inorganic rhenium compound or salt which includes a .sup.t Re target nuclide in an oxidation state of not more than +6, where t is 185 or 187, and the oxidized product nuclide is .sup.p ReO.sub.4.sup.-, where p is 186 when t is 185 and p is 188 when t is 187. 16. The method of claim 14 wherein the target is irradiated at a pressure which is less than about 1 mm Hg. 17. A method for producing a radionuclide via a (n,.gamma.) Szilard-Chalmers reaction, the method comprising 18. The method of claim 17 wherein the target comprises elemental rhenium or an inorganic rhenium compound or salt which includes a .sup.t Re target nuclide in an oxidation state of not more than +6, where t is 185 or 187, and the oxidized product nuclide is .sup.p ReO.sub.4.sup.-, where p is 186 when t is 185 and p is 188 when t is 187. 19. The method of claim 17 wherein the target is cooled by contacting the target or a housing enclosing the target with a circulating fluid having a temperature, before contacting the target or housing, of not more than about 100.degree. C. 20. A method for producing a radionuclide via a (n,.gamma.) Szilard-Chalmers reaction, the method comprising 21. The method of claim 20 wherein the target comprises elemental rhenium or an inorganic rhenium compound or salt which includes a .sup.t Re target nuclide in an oxidation state of not more than +6, where t is 185 or 187, and the oxidized product nuclide is .sup.p ReO.sub.4.sup.-, where p is 186 when t is 185 and p is 188 when t is 187. 22. The method of claim 20 wherein the projected thickness of the target layer is not more than about 15 nm. 23. A method for producing a radionuclide via a (n,.gamma.) Szilard-Chalmers reaction, the method comprising 24. The method of claim 23 wherein the target comprises elemental rhenium or an inorganic rhenium compound or salt which includes a .sup.t Re target nuclide in an oxidation state of not more than +6, where t is 185 or 187, and the oxidized product nuclide is .sup.p ReO.sub.4.sup.-, where p is 186 when t is 185 and p is 188 when t is 187. 25. The method of claim 23 wherein the prepared target is allowed to age for at least about 48 hours before being irradiated. 26. The method of claim 23 wherein the prepared target is allowed to age for at least about one week before being irradiated. 27. A method for producing .sup.186 Re or .sup.188 Re via a (n,.gamma.) Szilard-Chalmers reaction, the method comprising 28. The method of claim 27 wherein the product mixture is isotopically enriched in the product nuclide by a factor of at least about 3 relative to the irradiated mixture. 29. The method of claim 1 wherein the oxidizing agent is molecular oxygen present in an atmosphere surrounding the target. 30. The method of claim 1 wherein the oxidizing agent is atomic oxygen present in the target. 31. The method of claim 30 wherein the target comprises a rhenium oxide or a salt thereof which includes a .sup.185 Re or .sup.187 Re target nuclide in an oxidation state of not more than +6, and a M-oxide, where M is a metal other than rhenium. 32. The method of claim 31 wherein M is magnesium. 33. The method of claim 31 wherein M is tin. 34. The method of claim 31 wherein M is titanium. 35. The method of claim 30 wherein the target comprises a rhenium oxide or a salt thereof which includes a .sup.185 Re or .sup.187 Re target nuclide in an oxidation state of not more than +6, and a M-hydroxide where M is a metal other than rhenium. 36. The method of claim 35 wherein M is magnesium. 37. The method of claim 35 wherein M is tin. 38. The method of claim 35 wherein M is titanium. 39. The method of claim 12 wherein the oxidizing agent is atomic oxygen present in the target. 40. The method of claim 39 wherein the target comprises a rhenium oxide or a salt thereof which includes a .sup.185 Re or .sup.187 Re target nuclide in an oxidation state of not more than +6, and a M-oxide, where M is a metal other than rhenium. 41. The method of claim 40 wherein M is magnesium. 42. The method of claim 17 wherein the oxidizing agent is atomic oxygen present in the target. 43. The method of claim 20 wherein the oxidizing agent is atomic oxygen present in the target. 44. The method of claim 23 wherein the oxidizing agent is atomic oxygen present in the target. 45. The method of claim 27 wherein the oxidizing agent is atomic oxygen present in the target.
054950627	abstract	Soil including sand and clays contaminated with nuclear waste materials are decontaminated by treating with anhydrous liquid ammonia alone or in combination with solvated electrons. Methods comprise concentrating radionuclides, such as plutonium and uranium in the fines of soil and clay to yield residual soil products which are sufficiently free of contaminants to allow reclamation. Economics are improved over aqueous systems since ammonia can be recovered and recycled. By concentrating nuclear wastes in soil fines space requirements ordinarily needed for storage of untreated soil and handling costs can be significantly reduced.
048037168	abstract	An x-ray diagnostics installation for radiographs has a secondary radiation grid disposed in front of a holder for x-ray film. The secondary radiation grid is moveable during an exposure. Control circuitry controls the speed of movement of the secondary radiation grid dependent on the anticipated exposure time, such that imaging of the lamellae of the secondary radiation grid on the x-ray film is reliably prevented for all exposure times.
056446152	claims	1. An X-ray analysis apparatus comprising an X-ray collimator, which collimator comprises a plurality of plates (30a, 30b etc.) of a radiation absorbing material which are provided with openings, which plates are arranged so as to extend parallel and offset relative to one another in the propagation direction of the radiation, each plate comprising a pattern of holes (40, 42) with a given period p.sub.1 in a direction perpendicular to one of the sides of the holes, said period having a given opening fraction t.sub.1, the holes (40, 42) have a rectangular shape, and the collimator is provided with a first series of plates in which the ratio of two successive distances (d.sub.i, d.sub.i+1) between the plates of the series is equal to the given opening fraction t.sub.1 of the period p.sub.1. a plurality of plates (30a, 30b etc.) of a radiation absorbing material which are provided with openings, which plates are arranged so as to extend parallel and offset relative to one another in the propagation direction of the radiation, each plate comprising a pattern of holes (40, 42) with a given period p.sub.1 in a direction perpendicular to one of the sides of the holes, said period having a given opening fraction t.sub.1, the holes (40, 42) have a rectangular shape, and the collimator is provided with a first series of plates in which the ratio of two successive distances (d.sub.i, d.sub.i+1) between the plates of the series is equal to the given opening fraction t.sub.1 of the period p.sub.1. 2. An X-ray analysis apparatus as claimed in claim 1, characterized in that the holes furthermore have a given second period p.sub.2 in a second direction in the plane of the plates, perpendicular to the first direction, said second period having a given second opening fraction t.sub.2, the collimator being provided with a second series of plates in which the ratio of two successive distances between the plates of the second series equals the given second opening fraction t.sub.2 of the second period p.sub.2. 3. An X-ray collimator, comprising 4. A collimator as claimed in claim 3, characterized in that the holes furthermore have a given second period p.sub.2 in a second direction in the plane of the plates, perpendicular to the first direction, said second period having a given second opening fraction t.sub.2, the collimator being provided with a second series of plates in which the ratio of two successive distances between the plates of the second series equals the given second opening fraction t.sub.2 of the second period p.sub.2.
	abstract	A flow rate verification failure diagnosis apparatus is applied to a gas supply pipe system including flow rate control devices and a flow rate verification unit for detecting flow rate abnormality by measuring flow rate of each of the flow rate control devices on the basis of pressure measured by a pressure measurement device. The flow rate verification failure diagnosis apparatus comprises a failure diagnosis device having a mode to diagnose a failure in the pressure measurement device at a time of the flow rate verification unit detecting the flow rate abnormality, thereby the reliability of flow rate verification can be enhanced.
051679060	claims	1. A displacer rod for use in a nuclear reactor to effect a spectral shift in said reactor to achieve increased nuclear fuel efficiency, said nuclear reactor containing a fluid moderator juxtaposed with fuel elements containing said nuclear fuel, said displacer rod comprising a body containing a non-poison sacrificial material immersed in said moderator, said sacrificial material having a reduction in volume rate when subjected to said moderator whereby said body decreases in effective volume during operation of said nuclear reactor to thereby increase the effective volume of said moderator to compensate for excess reactivity of said fuel in said fuel elements during operation of said nuclear reactor. 2. The displacer rod of claim 1 wherein said body comprises: a sleeve member for being disposed within said moderator; elements of said non-poison sacrificial material positioned within said sleeve member; and means for introducing said moderator into said sleeve whereby said sacrificial material is reduced in volume by said moderator to achieve said effective decrease in volume of said displacer rod during operation of said nuclear reactor. a sleeve member for being disposed within said moderator-coolant; elements of said non-poison sacrificial material positioned within said sleeve member; and means for introducing said moderator-coolant into said sleeve whereby said sacrificial material is dissolved by said moderator-coolant to achieve said effective decrease in volume of said displacer rod during operation of said nuclear reactor. 3. The displacer rod of claim 2 wherein said sleeve member is provided with wall perforations as said means for introducing said moderator into said sleeve member. 4. The displacer rod of claim 3 wherein said sleeve member is provided with internal transverse support plates, said support plates provided with further perforations, said support plates supporting portions of said non-poison sacrificial material. 5. The improved displacer rod of claim 2 wherein said non-poison sacrificial material has a reduction in volume rate of about 0.5 to about 2.5 mg/cm.sup.2 -day. 6. The displacer rod of claim 2 wherein said moderator is water and wherein said non-poison sacrificial material is an alloy of aluminum having a dissolution rate in water of about 0.5 to about 2.5 mg/cm.sup.2 -day. 7. The displacer rod of claim 4 wherein said non-poison sacrificial material is in the form of elongated pellets supported on said support plates. 8. The displacer rod of claim 4 wherein said non-poison sacrificial material is in the form of spheres supported on said support plates. 9. The displacer rod of claim 1 wherein said sacrificial material varies in composition along a length of said displacer rod to achieve said dissolution rate according to a temperature gradient along said displacer rod in said nuclear reactor. 10. The displacer rod of claim 1 wherein said sacrificial material is provided with a surface-to-volume ratio configuration whereby said sacrificial material changes in volume as a function of time to match a change of excess reactivity of said nuclear reactor as a function of time. 11. A displacer rod for use in a pressurized water nuclear reactor to effect a spectral shift in said reactor to achieve increased nuclear fuel efficiency, said nuclear reactor containing a water moderator-coolant juxtaposed with fuel elements containing said nuclear fuel, said displacer rod comprising a body containing a non-poison sacrificial material immersed in said moderator-coolant, said sacrificial material having a dissolution rate when subjected to said moderator-coolant whereby said body decreases in effective volume during operation of said nuclear reactor to thereby increase the effective volume of said moderator-coolant to compensate for excess reactivity of said fuel in said fuel elements during operation of said nuclear reactor. 12. The displacer rod of claim 11 wherein said non-poison sacrificial material has a dissolution rate in water of about 0.5 to about 2.5 mg/cm.sup.2 -day. 13. The displacer rod of claim 12 wherein said non-poison sacrificial material is an alloy of aluminum. 14. The displacer rod of claim 11 wherein said body comprises: 15. The displacer rod of claim 14 wherein said sleeve member is provided with wall perforations as said means for introducing said moderator-coolant into said sleeve member. 16. The displacer rod of claim 15 wherein said sleeve member is provided with internal transverse support plates, said support plates provided with further perforations, said support plates supporting portions of said non-poison sacrificial material. 17. The displacer rod of claim 16 wherein said non-poison sacrificial material is in the form of elongated pellets supported on said support plates. 18. The displacer rod of claim 16 wherein said non-poison sacrificial material is in the form of spheres supported on said support plates. 19. The displacer rod of claim 11 wherein said non-poison sacrificial material varies in composition along a length of said displacer rod to achieve said dissolution rate according to a temperature gradient along said displacer rod in said nuclear reactor. 20. The displacer rod of claim 11 wherein said non-poison sacrificial material is provided with a surface-to-volume ratio configuration whereby said sacrificial material changes in volume as a function of time to match a change of excess reactivity of said nuclear reactor as a function of time.
	summary
059828390	description	DETAILED DESCRIPTION FIG. 1 is a side view schematic illustration of an inspection assembly 10 in accordance with one embodiment of the present invention coupled to a pipe 12 and positioned to inspect a first area, or portion, 14 of pipe 12. Inspection assembly 10 includes a mounting subassembly 16 and a scanning subassembly 18. Mounting subassembly 16 includes a support element 20, or x-axis tube, and a coupling element 26. X-axis tube 20 is coupled to a clamp 28, which is removably coupled to a segment 30 of pipe 12. X-axis tube 20 also is configured to rotatably couple to a remotely operated vehicle (not shown in FIG. 1). coupling element 26 is movably coupled to scanning subassembly 18 and x-axis tube 20. Scanning subassembly 18 includes a scanning arm 32, or y-axis tube, and a scanning head 34. Scanning arm 32 is slidably coupled to coupling element 26 of mounting subassembly 16. More particularly, scanning arm 32 extends through an opening (not shown in FIG. 1) in coupling element 26. Scanning head 34 is substantially "C" shaped and is movably coupled to an end 36 of scanning arm 32. Particularly, scanning head 34 is pivotally and rotatably coupled to end 36 of scanning arm 32. Scanning head 34 includes a transducer support assembly 38 for performing inspections. When inspecting pipe first portion 14, for example, scanning head 34 extends substantially transversely with respect to scanning arm 32. FIG. 2 is an exploded side view of inspection assembly 10 positioned to inspect first portion 14 of pipe 12. Coupling element 26 includes a first bore, or opening, 40 extending therethrough and sized to receive scanning arm 32. Opening 40 is provided with a keyway or similar device (not shown in FIG. 2) so that scanning arm 32 may slide through coupling element opening 40, but is substantially prevented from rotating within opening 40 relative to coupling element 26. Coupling element 26 further includes an arm driving assembly 42, e.g., a computerized servo motor fitted with a gear 44, a belt 46, and two idlers 48 and 50, respectively, adjacent opening 40. Arm driving assembly 42 is coupled to scanning arm 32 and is configured to move scanning arm 32 relative to coupling element 26 through opening 40, i.e., along a y-axis. Scanning arm 32 includes a head driving assembly 52 adjacent end 36 and coupled to scanning head 34. Head driving assembly 52 is coupled to a gear 54 and is configured to move scanning head 34 relative to scanning arm 32. Particularly, head driving assembly 52 is configured to rotate scanning head 34 about a pivot point 56 with respect to an x-axis, e.g., the horizontal axis, a y-axis, e.g., the vertical axis, and a z-axis extending through pivot point 56. Coupling element 26 also includes a second bore or opening (not shown in FIG. 2) sized to receive x-axis tube 20. X-axis tube 20 extends through the second opening and is slidably engaged to coupling element 26. The second opening, like first opening 40, is provided with a keyway or similar device to substantially prevent x-axis tube 20 from rotating within the second opening relative to coupling element 26. X-axis tube 20 also is rotatably mounted to a rod 58 which is affixed to a mount member 24. Mount member 24 is configured to couple to a remotely operated vehicle (not shown in FIG. 2) and includes a driving assembly 60, e.g., a computerized servo motor fitted with a gear and belts 61, which is coupled to support member 20 and configured to rotate support member 20 relative to mount member 24. Coupling element 26 also includes a driving assembly 62. Driving assembly 62 may, for example, be a servo motor 66 fitted with a belt 64 and idlers 68, and is configured to move coupling element 26 with respect to clamp 28 along the same axis as x-axis tube 20, i.e., along an x-axis. Accordingly, and with respect to the orientation illustrated in FIG. 2, scanning arm 32 sometimes is referred to as the y-axis tube and support element 20 sometimes is referred to as the x-axis tube. An air ram (not shown in FIG. 2) is secured to x-axis tube 20 and is coupled to clamp 28. The air ram is configured to releasably engage clamp 28 to pipe 12. FIG. 3 is an exploded top view of scanning head 34 of inspection assembly 10. As shown more clearly, scanning head 34 includes a substantially "C" shaped element 70 having an inner circumference 72 sized to receive first portion 14 of pipe 12. Transducer support assembly 38 is substantially "U" shaped and also is sized to receive first portion 14 of pipe 12. In addition, transducer support assembly 38 is movably coupled to inner circumference 72 of substantially "C" shaped element 70. Transducer support assembly 38 includes a back portion 74 having first and second legs 76 and 78 pivotally mounted thereto and extending from opposite ends thereof. Back portion 74 of transducer support assembly 38 has a radius of curvature substantially the same as the radius of curvature of inner circumference 72 of substantially "C" shaped element 70. A transducer element 80 is coupled to each leg 76 and 78, respectively, so that transducer elements 80 are substantially aligned. Scanning head 34 also includes an air ram 81 coupled to transducer support assembly 38. Air ram 81 is configured to position transducer elements 80 in contact with pipe portion 14. Particularly, when air ram 81 is pressurized, legs 76 and 78 move toward each other and into contact with pipe portion 14. Scanning head 34 further includes a transducer driving assembly 82, e.g., a computerized servo motor, for moving transducer support assembly 38 relative to substantially "C" shaped element 70. Particularly, transducer driving assembly 82 is coupled to transducer support assembly 38 and is configured to move back portion 74 of transducer support assembly 38 along inner circumference 72 of substantially "C" shaped element 70, thus rotating transducer support assembly 38 about pipe first portion 14. A rear portion 84 of substantially "C" shaped element 70 includes a notch 86. A gear 88 is positioned in notch 86 and coupled to scanning head 34. Gear 88 also is coupled to gear 54 (FIG. 2) to facilitate rotating scanning head 34 about an axis 90, i.e. the z-axis (FIG. 2). FIG. 4 is an exploded schematic partial front view illustration of pipe first portion 14 extending through scanning head 34. Particularly, as shown, pipe first portion 14 extends through substantially "C" shaped element 70. During ultrasound inspection, pipe first portion 14 extends between transducer support assembly legs 76 and 78 (only leg 76 is shown in FIG. 4), and each transducer leg 76 and 78 is substantially "L" shaped. Accordingly, transducer elements 80 (only one transducer element 80 is shown in FIG. 4) are spaced from substantially "C" shaped element 70. In addition, a spring 91 is attached to each transducer leg 76 and 78 to facilitate spacing legs 76 and 78 from pipe portion 14. Springs 91 are biased so that when air ram 81 is not pressurized, springs 91 move legs 76 and 78 away from pipe portion 14 to facilitate repositioning scanning head 34 to other positions on pipe 12. FIG. 5 is a side view schematic illustration of inspection assembly 10 positioned to inspect a second portion 92 of pipe 12. Second portion 92 of pipe 12 extends substantially perpendicularly from first pipe portion 14, and has a substantially similar diameter as first pipe portion 14. Clamp 28 is coupled to pipe segment 30, and scanning arm 32 extends from coupling element 26 so that scanning head 34 receives pipe second portion 92. In this position, scanning head 34 extends substantially co-planarly with scanning arm 32. FIG. 6 is a top view schematic illustration of inspection assembly 10 coupled to core spray piping 94 including a T-box 96, or junction box, and header pipes 98. Scanning head 34 is positioned to inspect one of header pipes 98. As shown more clearly in FIG. 6, transducer support assembly legs 76 and 78 (only transducer support assembly leg 76 is shown in FIG. 6) are substantially "L" shaped. FIG. 7 is a perspective view of a remotely operated vehicle (ROV) 100 utilized in accordance with one embodiment of the present invention. ROV 100 includes four propellers 102 which are coupled to a cage element 104 and are positioned to facilitate steering ROV 100 through water, e.g., the water in a reactor pressure vessel of a boiling water reactor. ROV 100 also includes a buoy element 106, which provides ROV 100 with a positive buoyancy, and a video camera (not shown in FIG. 7). ROV 100 is electrically coupled to a remote workstation (not shown), and is configured to transmit video signals from the video camera to the workstation. ROVs are well known. Automated inspection assembly 10 further includes a remote computerized motion control system. Particularly, a control program may be loaded into the remote workstation to generate control signals. The motion control system is coupled to each drive assembly 42, 52, 62 and 82 and the control signals are transmitted to each drive assembly 42, 52, 62 and 82, respectively. Particularly, the motion control system controls the movement of: scanning arm 32 with respect to coupling element 26; scanning head 34 with respect to scanning arm 32; coupling element 26 with respect to mount element 24; and transducer support assembly 38 with respect to substantially "C" shaped element 70. The motion control system also may be coupled to driving assembly 60 and configured to control rotation of support member 20 relative to mount member 24. In operation, inspection assembly 10 is positioned in an RPV and an operator, using remote control, controls ROV 100 so that inspection assembly 10 moves to the pipe to be inspected, e.g., pipe 12. After reaching pipe 12, motor drive assembly 60 is activated to facilitate mounting clamp 28 to pipe 12. Clamp 28 is then positioned around pipe 12, and the operator actuates the air ram to releasably mount mounting subassembly 16 to pipe 12 with clamp 28. To scan first portion 14 of pipe 12 (FIG. 1), for example, scanning head 34 is positioned proximate first pipe portion 14 so that first pipe portion 14 extends between legs 76 and 78, respectively, of transducer support assembly 38. Particularly, the operator actuates arm driving assembly 42 to position scanning head 34 adjacent pipe first portion 14, and the operator actuates head driving assembly 52 to move scanning head 34 and position pipe first portion 14 between transducer support assembly legs 76 and 78, respectively. The operator then pressurizes air ram 81 to place transducer elements 80 in contact with pipe first portion 14. The operator then actuates the computerized motion control system to scan pipe first portion 14 and inspect the integrity thereof. Particularly, driving assemblies 42, 52, 62 and 82 are actuated so that transducer elements 80 rotate circumferentially about pipe first portion 14 and move axially with respect to pipe first portion 14. More specifically, transducer elements 80 are moved in accordance with the following cycle: rotate circumferentially about pipe first portion 14 for a first predetermined distance; move axially in a first direction with respect to pipe first portion 14 for a second predetermined distance; rotate circumferentially about pipe first portion 14 for a third predetermined distance; and move axially in a second direction, which is substantially opposite the first direction, for a fourth predetermined distance. This cycle is then repeated so that substantially the entire circumference of pipe first portion 14 is scanned. During the scan, transducer elements 80 transmit signals to the operator in a well known manner, and such signals are representative of the integrity of inspected pipe first portion 14. After inspecting pipe first portion 14, second pipe portion 92, for example, may be inspected without removing clamp 28 from pipe 12. Particularly, air ram 81 is depressurized so that transducer elements 80 are spaced from pipe first portion 14 and, referring again to FIG. 5, scanning head 34 is rotated so that it is substantially co-planar with scanning arm 32. Scanning arm 32 is then moved with respect to coupling element 26 so that pipe second portion 92 extends between legs 76 and 78, respectively, of transducer support assembly 38. Air ram 81 is again pressurized and transducer support assembly 38 is then rotated about pipe second portion 92 in accordance with the above described cycle to inspect the integrity of pipe second portion 92. The above described automated inspection assembly is particularly suitable for use in nuclear reactor applications and is easy to install and controllable for forming high quality piping inspections. The assembly also may be operated from a remote location other than the bridge. Of course, the assembly is not limited to practice in a nuclear reactor environment and is believed to be useful in many other underwater pipe inspection applications. From the preceding description of the present invention, it is evident that the objects of the invention are attained. Although the invention has been described and illustrated in detail, it is to be clearly understood that the same is intended by way of illustration and example only and is not be taken by way of limitation. For example, the inspection assembly was described in connection with inspecting piping in nuclear reactors. Such assembly may, however, also be utilized to inspect other piping located under water, e.g., oil rig piping. In addition, while the drive assemblies described above included servo motors, such drive assemblies alternatively may include stepper motors. Accordingly, the spirit and scope of the invention are to be limited only by the terms of the appended claims.
052992527	claims	1. A fluorescent X-ray film thickness measuring apparatus for measuring a film thickness of a sample, said film thickness measuring apparatus comprising: a collimator having an aperture for forming a primary X-ray beam having a beam axis and a rectangular cross section; means connected to said collimator for rotating said collimator around the primary X-ray beam axis to a desired angular position; and means for monitoring a portion of the sample comprising means for overlapping a representation of the sample portion with a representation of the orientation of the rectangular cross section of the formed primary X-ray beam. 2. A fluorescent X-ray film thickness measuring apparatus comprising: an X-ray tube for generating a primary X-ray; a collimator having a rectangular aperture for forming the primary X-ray into a beam having a beam axis and a rectangular cross section, the rectangular aperture and the rectangular cross section each having a long dimension; means for holding a sample at a measuring position for irradiation of a portion of the sample by the beam in order to cause fluorescent X-rays to be emitted from the sample portion, the sample portion having a long dimension; an X-ray detector disposed for detecting the fluorescent X-rays; a mirror for reflecting an image of the sample at the measuring position; display means for displaying the image of the sample portion reflected by said mirror; a collimator drive motor coupled to said collimator for rotating said collimator about the beam axis and for matching the orientation of the long dimension of the aperture with the orientation of the long dimension of the sample portion; and indicating means for indicating the orientation of the aperture and sending information indicating the orientation to said display means.
048062774	abstract	The present invention relates to a decontamination method in which an object to be decontaminated is immersed in a liquid, bubbles are produced by blowing vapor in the liquid, and these bubbles are caused to burst on a solid surface which constitutes the object to be decontaminated which is brought into contact with the liquid, whereby substances adhered to the solid surface are separated and removed by the impulsive force produced when the bubbles burst. Also provided is a method of decontaminating solid surfaces which exhibits a high degree of efficiency and a high level of safety.
053496140	claims	1. A plug installation tool for remotely installing a plug in a steam outlet nozzle of a reactor pressure vessel having a flange, comprising: a strongback assembly on which said plug is securely mounted; movable support means for supporting said strongback assembly, said movable support means being movable from an extended state to a collapsed state; rigid tool hanging means for hanging said movable support means from said flange and inside said vessel at an azimuth and an elevation such that said plug is aligned with but not inside said steam line nozzle when said movable support means is in said extended state; and first actuating means coupled to said movable support means such that said movable support means moves between said extended state and said collapsed state in response to manipulation of said first actuating means, whereby said plug is inserted inside said steam line nozzle during movement of said movable support means from said extended state to said collapsed state. first and second support members; means for translating said second support member toward said first support member from a first position to a second position; rigid means for hanging said first support member from said flange and inside said vessel at an azimuth and an elevation such that said plug is aligned with but not inside said steam line nozzle when said second support member is in said first position; a strongback assembly coupled to said second support member for securely supporting said plug; and first actuating means coupled to said translating means such that said second support member is translated from said first position to said second position during manipulation of said first actuating means, whereby said plug is inserted in said steam line nozzle during translation of said second support member from said first position to said second position. first and second rigid straight support members; a hanging bracket assembly coupled to support said first support member and designed to latch onto a top portion of a flange at a top of a reactor pressure vessel in a manner that prevents displacement of said first support member in downward and radially inward directions relative to said reactor pressure vessel; a collapsible assembly coupled to said first and second support members, said second support member being translated toward said first support member during collapse of said collapsible assembly; a mounting assembly coupled to said second support member for securely supporting a plug to be translated; and a first actuating element coupled to said collapsible assembly such that said collapsible assembly collapses in response to manipulation of said first actuating element. 2. The plug installation tool as defined in claim 1, wherein said movable support means comprises a scissors jack mechanism pivotably coupled to a carriage and said first actuating means comprises an actuating screw coupled to said carriage, said scissors jack mechanism moving between said extended state and said collapsed state in response to rotation of said actuating screw. 3. The plug installation tool as defined in claim 2, wherein said strongback assembly comprises notches for receiving a portion of a motor and means for latching said motor portion to said strongback assembly, said latching means being remotely releasable by manipulation of latch handle means connected to said latching means. 4. The plug installation tool as defined in claim 1, further comprising adjustable means for adjusting the elevation of said movable support means relative to said tool hanging means. 5. The plug installation tool as defined in claim 1, further comprising adjustable means for adjusting the elevation of said strongback assembly relative to said movable support means, and second actuating means coupled to said adjustable means such that said adjustable means moves between an extended state and an unextended state in response to manipulation of said second actuating means. 6. The plug installation tool as defined in claim 1, wherein said tool hanging means further comprises azimuth guide means for hanging said plug at a predetermined azimuth relative to said vessel. 7. The plug installation tool as defined in claim 2, wherein said movable support means further comprises an actuating channel coupled to said tool hanging means and a plug support tube coupled to said strongback assembly, and said scissors jack mechanism comprises first and second scissor bars, said first scissors bar being pivotably coupled at one end to said plug support tube and at the other end to said carriage, said second scissors bar being pivotably coupled at one end to a collar slidable along said plug support tube and at the other end to said actuating channel, and said first and second scissors bars being pivotably coupled to each other. 8. The plug installation tool as defined in claim 4, further comprising tool handling means pivotably coupled to said tool hanging means, said tool handling means being rotatable between first and second angular positions, and releasable means for locking said tool handling means in said first angular position. 9. A plug installation tool for remotely installing a plug in a steam outlet nozzle of a reactor pressure vessel having a flange, comprising: 10. The plug installation tool as defined in claim 9, wherein said translating means comprises a scissors jack mechanism pivotably coupled to a carriage and said first actuating means comprises an actuating screw coupled to said carriage, said scissors jack mechanism moving from an extended state to a collapsed state in response to rotation of said first actuating screw. 11. The plug installation tool as defined in claim 10, wherein said strongback assembly comprises notches for receiving a portion of a motor and means for latching said motor portion to said strongback assembly, said latching means being remotely releasable by manipulation of latch handle means connected to said latching means. 12. The plug installation tool as defined in claim 9, further comprising adjustable means for adjusting the elevation of said first support member relative to said hanging means. 13. The plug installation tool as defined in claim 9, further comprising adjustable means for adjusting the elevation of said strongback assembly relative to said translating means, and second actuating means coupled to said adjustable means such that said adjustable means moves between an extended state and an unextended state in response to manipulation of said second actuating means. 14. The plug installation tool as defined in claim 9, wherein said hanging means further comprises azimuth guide means for hanging said plug at a predetermined azimuth relative to said vessel. 15. The plug installation tool as defined in claim 10, wherein said first support member comprises an actuating channel and said second support member comprises a plug support tube, and said scissors jack mechanism comprises first and second scissors bars, said first scissors bar being pivotably coupled at one end to said plug support tube and at the other end to said carriage, said second scissors bar being pivotably coupled at one end to a collar slidable along said plug support tube and at the other end to said actuating channel, and said first and second scissors bars being pivotably coupled to each other. 16. The plug installation tool as defined in claim 12, further comprising handling means pivotably coupled to said hanging means, said handling means being rotatable between first and second angular positions, and releasable means for locking said handling means in said first angular position. 17. A plug installation tool comprising: 18. The plug installation tool as defined in claim 17, wherein said collapsible assembly comprises a scissors jack mechanism pivotably coupled to a carriage and said first actuating element comprises an actuating screw coupled to said carriage, said scissors jack mechanism moving from an extended state to a collapsed state in response to manipulation of said actuating screw. 19. The plug installation tool as defined in claim 17, further comprising an adjustable arrangement for adjusting the elevation of said mounting assembly relative to said collapsible assembly, and a second actuating element coupled to said adjustable arrangement such that said adjustable arrangement moves between an extended state and an unextended state in response to manipulation of said second actuating element. 20. The plug installation tool as defined in claim 18, wherein said first support member comprises an actuating channel and said second support member comprises a plug support tube, and said scissors jack mechanism comprises first and second scissors bars, said first scissors bar being pivotably coupled at one end to said plug support tube and at the other end to said carriage, said second scissors bar being pivotably coupled at one end to a collar slidable along said plug support tube and at the other end to said actuating channel, and said first and second scissors bars being pivotably coupled to each other.
052606210	description	DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention is shown in FIG. 1 as comprising a stack 22 of alternate emitting nuclide and semiconductor-junction strata, an inner heavy metal shield 24 that absorbs nuclear radiation escaping from stack 22, an intermediate high thermal impedance housing 26 that retards heat transfer from within stack 22, and an external metal casing 28 that snugly receives housing 26. The electrical output of stack 22 is established across a positive terminal 30 and a negative terminal 32. Negative terminal 32 connects electrically to metal casing 28. Positive terminal 30 projects through an opening in an electrically insulating cap 33 at the top of casing 28. As shown in FIG. 2, stack 22 is characterized by a sequence of say ten power cells of the type shown in FIGS. 2 and 3. Each power cell includes a pair of semiconductor-junction strata 34 between which is sandwiched a radionuclide emitter stratum 36. Each semiconductor-junction stratum typically ranges in thickness from 1 to 250 microns. At the lower end of this range, the semi-conductor junction stratum, in one form, is deposited on a substrate composed, for example, of silicon. Each emitter stratum typically ranges in thickness from 0.1 to 5 microns. The upper thickness limit is determined by undue self-absorption of emitted particles. Each semiconductor-junction stratum has an electrically positive face region 38 and an electrically negative face region 40. Positive face region 38 is established by subjection to a p-dopant selected, for example, from the class consisting of zinc and cadmium. Negative face region 40 is established by subjection to an n-dopant selected, for example, from the class consisting of silicon and sulfur. A lead 42 from positive face region 38 and a lead 44 from negative face region 40 connect into the remainder of the electrical system. In one form, emitter strata 36 produce alpha particles characterized by a monoenergetic level in excess of 4.5 MeV and ranging upwardly to about 6.5 MeV and ordinarily 5 to 6.1 MeV. In another form, emitter strata 36 produce beta particles having a maximum energy level in excess of 0.01 MeV and ranging upwardly to about 3.0 MeV. Typical compositions of emitter strata 36 are selected from the class consisting of the isotopes listed in the following table, in which E.sub.max refers to maximum energy, E.sub.avg to average energy, and T.sub.1/2 to half life: ______________________________________ Type of Maximum Half Emitter Energy Life Isotope (Mev) (Mev) Years ______________________________________ H.sup.3 .beta. 0.018 12.3 Ni.sup.63 .beta. 0.067 92.0 Sr.sup.30 /Y.sup.90 .beta. 0.545/ 27.7 2.26 Pm.sup.147 .beta. 0.230 2.62 Tl.sup.204 .beta. 0.765 3.75 Kr.sup.85 .beta. 0.670 10.9 Pu.sup.238 .alpha. 5.50 66.4 Cm.sup.242 .alpha. 6.10 0.45 Cm.sup.244 .alpha. 5.80 18.0 Po.sup.210 .alpha. 5.30 .38 ______________________________________ Preferably, voltaic-junctions strata 34 are inorganic semiconductors which are binary, ternary and/or quarternary compounds of Group III and Group V elements of the Periodic Table. Preferred Group III elements are selected form the class consisting of boron, aluminum, gallium and indium. Preferred Group V elements are selected from the class consisting of phosphorous, arsenic and antimony. These compounds are typified by the class consisting of AlGaAs, GaAsP, AlInP, InAlAs, AlAsSb, AlGaInP, AlGaInAs, AlGaAsSb, InGaAs, GaAsSb, InAsP, AlGaSb, AlInSb, InGaAsP, AlGaAsSb and AlGaInSb. Equivalent circuits of various embodiments of the battery of FIGS. 1 to 3 are shown in FIGS. 4 to 7. These embodiments are illustrated as schematics in which various series and parallel combinations achieve a range of output currents and voltages. In FIG. 4, a plurality of cells 50 are arranged in parallel to produce relatively high current. In FIG. 5, a plurality of cells 52 are arranged in series to produce relatively high voltage. FIG. 7 shows a plurality of parallel strings of cells 54, each string having a plurality of cells in series. FIG. 8 shows a plurality of submodules 56 in series, each submodule having a plurality of cells in parallel. EXAMPLE The present invention is specifically illustrated by a configuration of the cell of FIGS. 1, 2 and 3 in which voltaic junction 34 is an indium phosphide stratum, opposite face regions of which are implanted with (1) zinc ions to establish a p-region and (2) silicon ions to establish an n-region. Each voltaic-junction stratum is approximately 150 microns thick. In one version of this example, emitter stratum is composed of Pu-238. In another version of this example, the emitter stratum is composed of Sr-90. Each emitter stratum is approximately 1.5 microns in thickness. Radiation shielding enclosure 24 is composed of tantalum. Thermal insulating enclosure 26 is composed of ceramic. The thickness and composition of insulating enclosure 26 is selected to maintain the temperature of stack 22 at 50.degree. C. in an environment where the temperature is no greater than approximately 20.degree. C., i.e. (1) for space applications in which the cell is shielded from heating by solar radiation, or (2) no greater than 35.degree. C., i.e., for terrestrial applications in which the cell operates at room or body temperature. The indium phosphide anneals most of its radiation damage at temperatures below 100.degree. C. OPERATION AND CONCLUSIONS The present invention contemplates semiconductors with three unique features (1) relatively high radiation resistance, (2) continued photovoltaic function at elevated temperatures, and (3) real time annealing of radiation damage in the same temperature range. These features support a high energy density radio-nuclide battery operating with relatively high energy beta and/or alpha particle sources. The design of these batteries takes into consideration the rapidity of annealing of radiation damage in InP when irradiated at 100.degree. C., continued operation during annealing, and tolerance of different intensities of alpha and beta radiation for different applications. Annealing at elevated temperature supports a large dose rate with minimal degradation in power output. These properties make it possible to consider a much wider range of radioisotopes than has been possible with silicon betavoltaic cells. Since most previously developed silicon-based beta voltaic cells have used Pm-147, this nuclide serves as a good basis for comparison of prior art batteries with batteries of the present invention. Pm-147 emits beta particles with a peak energy of 0.23 MeV, average energy of 0.063 MeV, and half-life of 2.62 years. Promethium cells generally provide a maximum power of 1000 .mu.W/cm.sup.3 which drops to 266 .mu.W/cm.sup.3 after 5 years. At least 1.5 Ci/cm.sup.2 has been required to produce 50 .mu.W/cm.sup.2. To illustrate the advantage provided by InP, the Pm-147 silicon cell is compared below in Table 2 with other beta isotopes and an alpha emitter. In Table 2, T refers to half-life, E.sub.max refers to maximum energy, Ci/cm.sup.2 refers to curies per square centimeter, BOL refers to "Beginning Of Life", EOL refers to "End Of Life", W refers to watts and h refers to hours. ______________________________________ Output (5 years) T.sub.1/2 E.sub.max Activity BOL EOL Total Isotope Years MeV Ci/cm.sup.2 W/cm.sup.3 W/cm.sup.3 W-h/cm.sup.3 ______________________________________ Pm-147 2.62 0.230 1.50 1000 266 24.3 Tl-204 3.75 0.765 1.05 672 266 19.2 Sr-90 27.7 0.545 0.19 301 266 13.3 Pu-238 86.4 5.5 0.004 276 266 11.9 ______________________________________ The activity level for each of the above isotopes was adjusted to give the same End Of Life power density as Pm-147. This means that the longer lived isotopes require a much smaller activity level to achieve the same End Of Life power level. We note that total energy output of the Pu-238 powered cell at the end of twenty years is calculated to be 44.7 W-h/cm.sup.3 and its power density 235 W-h/cm.sup.3. After 20 years, the Pm-147 cell is calculated to generate just 33.0 W-h/cm.sup.2 and its power density is calculated to be 5.04 .mu.Wcm.sup.3. Another method of comparison is by lifetimes, assuming that the same average power is produced. Table 3 below compares the power output half-life for four cases, all starting at 1 mW/cm.sup.3 and generating an average power of 722 .mu.W/cm.sup.3. ______________________________________ Best Chemical Batteries Hg-Zn (chemical battery) 1 Month 0.55 W-h/cm.sup.3 Best Betavoltaic - Si Pm.sup.147 -Si 16.6 W-h/cm.sup.3 2.6 Years InP at Room Temp (No Anneal) Sr.sup.90 /Y.sup.90 -InP 182 W-h/cm.sup.3 28 Years InP with Anneal Pu.sup.238 -InP 544 W-H/cm.sup.3 86 Years ______________________________________ It is to be noted that even without annealing, the higher energy output of Sr-90 is far superior to previous configurations based on Si junctions, even ignoring emissions of the daughter nuclide, Y-90, which would also contribute. Annealing during operation allows an alpha source, such as Pu-238, to provide enormous operating times. The present invention anticipates that a nuclide with an extended alpha emitting decay chain (Ra-226) actually may increase power output as it ages. It is coincidence in this comparison, that the long lived materials actually use less radioactive material, in curies (Ci) or becquerel (Bq), than Pm-147. The number of curies required to provide a given power level is directly related to lifetime and inversely related to average energy of the emitted particles. Thus: for Pm-147, the activity is 1.5 Ci/cm.sup.2 ; PA1 for Sr-90, the activity is 0.63 Ci/cm.sup.2 ; and PA1 for Pu-238, the activity is 0.017 Ci/cm.sup.2. It is found that damage effectiveness of electrons drops rapidly with energy below 1 MeV and, for a pure Sr-90 beta spectrum, is estimated to be 1.2% of that for 1 MeV electrons. Tests have established that 10.sup.16 /cm.sup.2 of 1 MeV electrons drop InP cell efficiency to 80% of its initial value at room temperature. Considering the spread of energies in a Sr-90 beta spectrum, there is a requirement for an exposure of 10.sup.18 Sr-90 beta particles to produce the same effect as a 1 MeV electron beam. For 0.667 curies/cm.sup.2 of Sr-90 and again neglecting the daughter emissions, approximately 2.47.times.10.sup.10 electrons/cm.sup.2 /sec penetrate one face of the InP stratum. Since activity is sandwiched between two cells, actual curies/cm.sup.2 is 1.33 Ci from which 2.47.times.10 .sup.10 /sec follows. Exposure time required to reach a fluence of 10.sup.18 is estimated at 4.05.times.10.sup.7 seconds, 1.125.times.10.sup.4 hours, or 1.28 years. An electron beam of 10 .mu.A/cm.sup.2 delivers a fluence of 10.sup.16 /cm.sup.2 in 2.67 minutes so that test irradiation takes no longer than an hour. Efficiency of isotope powered cells is the fraction of particle energy converted to electrical energy. For Pm-147 powered silicon cells, it has been found that 5.55.times.10.sup.10 beta particles per square centimeter per second yielded a power output of 25 .mu.W/cm.sup.2. For Pm-147 beta particles with an average energy of 0.0625 MeV the input power is 555 .mu.W/cm.sup.2. The total efficiency achieved in this case is 4.5%. The theoretical efficiency achievable has been calculated as greater than 10%. High energy particles, such as alpha particles from Pu-238, will displace atoms from their normal bound positions in a crystalline semiconductor, such as indium phosphide. The number of atoms displaced depends upon the energy and mass of the incident particle, the mass of the target atoms, and the minimum energy required to remove it from its bound lattice position. A displaced atom can have considerable recoil energy immediately after being struck by the incident particles. The excess energy is dissipated by ionizing and displacing adjacent atoms in the crystal lattice until the primary recoil energy has dropped to thermal energies (0.025 eV at room temperature). The end result is a number of vacant lattice sites (vacancies) and displaced atoms in interstitual positions in the lattice (interstitials). At room temperature (300.degree. K.) the vacancies and interstitials are mobile, and diffuse through the crystal lattice until they interact with other defects or lattice impurities, or reach the surface, or annihilate. Many of the complex defects that result from these interactions are stable at room temperature and introduce energy levels throughout the forbidden gap of the semiconductor. The defect energy levels can reduce the lifetime of minority carriers, the majority carrier concentration, and the mobility of the majority carriers. All of these properties have a major impact on the operation of a device such as a solar cell. Each semiconductor material exposed to the same radiation develops a spectrum of radiation defects that are unique to that material. In addition, for a given material, the spectrum of defects observed is a strong function of the temperature at which the material is irradiated. At sufficiently low temperatures, the primary vacancies and interstitials can be "frozen in", and the changes in semiconductor properties associated with them studied as the semiconductor is warmed to room temperature and above. At sufficiently high temperatures, the material can be restored to its original state. Note that in semiconductors such as silicon the temperature required to restore the original properties is so high that it would destroy any device composed of the material. At such a temperature, impurities deliberately implanted in certain regions of the device to form p-n junctions diffuse throughout the material, and metal contacts are destroyed, thereby rendering the device useless. In accordance with the present invention, III-V compounds like indium phosphide are unique in that a large fraction of the radiation induced defects anneal at fairly low temperatures, in the case of indium phosphide, below 100.degree. C. The integrity of such devices therefore are maintained. The major factor governing the ability of a material to anneal damage is traceable to the stability of the complex defects formed under irradiation. Whether a semiconductor will anneal radiation induced damage at low temperatures or not has to be determined by experiment. No single property or combination of properties has been identified as being responsible for such behavior. In the case of indium phosphide, experiments have shown that the net defect density introduced by energetic particles is much less than in the case of common semiconductors such as silicon and gallium arsenide. The latter semiconductors, when irradiated at room temperature, form defects which are stable and which markedly affect their properties. Semiconductors that exhibit annealing behavior at particular temperatures can be determined only by experiment. Factors such as energy gap, threshold energy for displacement, diffusion coefficient, and defect mobility are not sufficient to identify a likely material.
054229227	abstract	A fuel assembly and a reactor core using same which are able to increase size of the fuel assembly with ensuring thermal margin and reactor shut down margin.. A distance between centers of adjacent fuel assemblies is about 23 cm, which is enlarged about 1.5 times of conventional fuel assemblies. A thickness of water gap region is about 16 cm, which is relatively thinner than that of prior art. While, H/U ratio is about 5 as same as that of the prior art, and decreasing amount of non-boiling water in the water gap region is arranged in a channel box as water rods. Consequently, a ratio of transversal cross section area of the water rods to transversal cross section area of the fuel rods becomes about 0.6, and local power peaking factor can be decreased and thermal margin can be increased. Further, the transversal cross section area of the water rod is selected to be 15 cm.sup.2 so as to ensure the reactor shut down margin by reducing excess reactivity.
	description	This application claims the benefit of U.S. Provisional Application No. 61/625,764 filed Apr. 18, 2012 and titled “UPPER INTERNALS”. U.S. Provisional Application No. 61/625,764 filed Apr. 18, 2012 titled “UPPER INTERNALS” is hereby incorporated by reference in its entirety into the specification of this application. This application claims the benefit of U.S. Provisional Application No. 61/625,399 filed Apr. 17, 2012 and titled “RISER TRANSITION”. U.S. Provisional Application No. 61/625,399 filed Apr. 17, 2012 titled “RISER TRANSITION” is hereby incorporated by reference in its entirety into the specification of this application. The following relates to the nuclear reactor arts and related arts. There is increasing interest in compact reactor designs. Benefits include: reduced likelihood and severity of abnormal events such as loss of a coolant accident (LOCA) event (both due to a reduction in vessel penetrations and the use of a smaller containment structure commensurate with the size of the compact reactor); a smaller and more readily secured nuclear reactor island (see Noel, “Nuclear Power Facility”, U.S. Pub. No. 2010/0207261 A1 published Aug. 16, 2012 which is incorporated herein by reference in its entirety); increased ability to employ nuclear power to supply smaller power grids, e.g. using a 300 MWe or smaller compact reactor, sometimes referred to as a small modular reactor (SMR); scalability as one or more SMR units can be deployed depending upon the requisite power level; and so forth. Some compact reactor designs are disclosed, for example, in Thome et al., “Integral Helical-Coil Pressurized Water Nuclear Reactor”, U.S. Pub. No. 2010/0316181 A1 published Dec. 16, 2010 which is incorporated by reference in its entirety; Malloy et al., “Compact Nuclear Reactor”, U.S. Pub. No. 2012/0076254 A1 published Mar. 29, 2012 which is incorporated by reference in its entirety. These compact reactors are of the pressurized water reactor (PWR) type in which a nuclear reactor core is immersed in primary coolant water at or near the bottom of a pressure vessel, and the primary coolant is suitably light water maintained in a subcooled liquid phase in a cylindrical pressure vessel that is mounted generally upright (that is, with its cylinder axis oriented vertically). A hollow cylindrical central riser is disposed concentrically inside the pressure vessel and (together with the core basket or shroud) defines a primary coolant circuit in which coolant flows upward through the reactor core and central riser, discharges from the top of the central riser, and reverses direction to flow downward back to below the reactor core through a downcomer annulus defined between the pressure vessel and the central riser. The nuclear core is built up from multiple fuel assemblies each comprising a bundle of fuel rods containing fissile material (typically 235U). The compact reactors disclosed in Thome et al. and Malloy et al. are integral PWR designs in which the steam generator(s) is disposed inside the pressure vessel, namely in the downcomer annulus in these designs. Integral PWR designs eliminate the external primary coolant loop carrying radioactive primary coolant. The designs disclosed in Thome et al. and Malloy et al. employ internal reactor coolant pumps (RCPs), but use of external RCPs (e.g. with a dry stator and wet rotor/impeller assembly, or with a dry stator and dry rotor coupled with a rotor via a suitable mechanical vessel penetration) is also contemplated (as is a natural circulation variant that does not employ RCPs). The designs disclosed in Thome et al. and Malloy et al. further employ internal pressurizers in which a steam bubble at the top of the pressure vessel is buffered from the remainder of the pressure vessel by a baffle plate or the like, and heaters, spargers, or so forth enable adjustment of the temperature (and hence pressure) of the steam bubble. The internal pressurizer avoids large diameter piping that would otherwise connect with an external pressurizer. In a typical PWR design, upper internals located above the reactor core include control rod assemblies with neutron-absorbing control rods that are inserted into/raised out of the reactor core by control rod drive mechanisms (CRDMs). These upper internals include control rod assemblies (CRAs) comprising neutron-absorbing control rods yoked together by a spider. Conventionally, the CRDMs employ motors mounted on tubular pressure boundary extensions extending above the pressure vessel, which are connected with the CRAs via suitable connecting rods. In this design, the complex motor stator can be outside the pressure boundary and magnetically coupled with the motor rotor disposed inside the tubular pressure boundary extension. The upper internals also include guide frames constructed as plates held together by tie rods, with passages sized to cam against and guide the translating CRA's. For compact reactor designs, it is contemplated to replace the external CRDM motors with wholly internal CRDM motors. See Stambaugh et al., “Control Rod Drive Mechanism for Nuclear Reactor”, U.S. Pub. No. 2010/0316177 A1 published Dec. 16, 2010 which is incorporated herein by reference in its entirety; and DeSantis, “Control Rod Drive Mechanism for Nuclear Reactor”, U.S. Pub. No. 2011/0222640 A1 published Sep. 15, 2011 which is incorporated herein by reference in its entirety. Advantageously, only electrical vessel penetrations are needed to power the internal CRDM motors. In some embodiments, the scram latch is hydraulically driven, so that the internal CRDM also requires hydraulic vessel penetrations, but these are of small diameter and carry primary coolant water as the hydraulic working fluid. The use of internal CRDM motors shortens the connecting rods, which reduces the overall weight, which in turn reduces the gravitational impetus for scram. To counteract this effect, some designs employ a yoke that is weighted as compared with a conventional spider, and/or may employ a weighted connecting rod. See Shargots et al., “Terminal Elements for Coupling Connecting Rods and Control Rod Assemblies for a Nuclear Reactor”, U.S. Pub. No. 2012/0051482 A1 published Mar. 1, 2012 which is incorporated herein by reference in its entirety. Another design improvement is to replace the conventional guide frames which employ spaced apart guide plates held together by tie rods with a continuous columnar guide frame that provides continuous guidance to the translating CRA's. See Shargots et al, “Support Structure for a Control Rod Assembly of a Nuclear Reactor”, U.S. Pub. No. 2012/0099691 A1 published Apr. 26, 2012 which is incorporated herein by reference in its entirety. The use of internal CRDMs and/or continuous guide frames and/or internal RCPs introduces substantial volume, weight, and complexity to the upper internals. These internals are “upper” internals in that they are located above the reactor core, and they must be removed prior to reactor refueling in order to provide access to the reactor core. In principle, some components (especially the internal RCPs) can be located below the reactor core, but this would introduce vessel penetrations below the reactor core which is undesirable since a LOCA at such low vessel penetrations can drain the primary coolant to a level below the top of the reactor core, thus exposing the fuel rods. Another option is to employ external RCPs, but this still leaves the complex internal CRDMs and guide frames. Disclosed herein are improvements that provide various benefits that will become apparent to the skilled artisan upon reading the following. In one disclosed aspect, an apparatus comprises: a pressure vessel comprising an upper vessel section and a lower vessel section connected by a mid-flange; a nuclear reactor core comprising fissile material disposed in the lower vessel section; upper internals disposed in the lower vessel section above the nuclear reactor core, the upper internals including at least internal control rod drive mechanisms (CRDMs) with CRDM motors mounted on a suspended support assembly; a hollow cylindrical central riser disposed in the upper vessel section; a hollow cylindrical section disposed in the lower vessel section and surrounding the nuclear reactor core; and a riser transition element connecting with the hollow cylindrical central riser and the hollow cylindrical section to form a continuous hollow cylindrical flow separator between a columnar hot leg flowing inside the continuous hollow cylindrical flow separator and an annular cold leg flowing in a downcomer annulus surrounding the continuous hollow cylindrical flow separator. The riser transition element is welded to the mid-flange of the pressure vessel and to the suspended support assembly of the upper internals to suspend the upper internals from the mid-flange In some embodiments the hollow cylindrical section disposed in the lower vessel section and surrounding the nuclear reactor core comprises a core basket or shroud. In some embodiments the riser transition section comprises an annular main body, and gussets extending outward and upward from the annular main body and welded to the mid-flange of the pressure vessel. In some such embodiments the each gusset comprises a first section extending laterally away from the annular main body, a second section extending upward and laterally away from the first section, and a third section extending laterally away from the second section. In another disclosed aspect, an apparatus comprises a riser transition element and tie rod bosses having upper ends welded to the riser transition element. The riser transition element includes an annular main body configured to connect with the lower end of a hollow cylindrical central riser of a small modular nuclear reactor (SMR) and with the upper end of a core basket or shroud of a nuclear reactor core of the SMR to form a continuous hollow cylindrical flow separator for the SMR, and gussets extending upwardly away from the annular main body. The apparatus may further comprise a flange to which outer ends of the gussets of the riser transition are welded. In such embodiments, each gusset of the riser transition element may include a horizontal cantilevered portion welded to the flange, and a tensile strained portion welded to the horizontal cantilevered portion and angled downward. The apparatus may further comprise upper internals including at least control rod drive mechanisms (CRDMs) with CRDM motors mounted in a support assembly suspended from tie rods, and upper ends of the tie rods of the support assembly are connected with the tie rod bosses such that the upper internals are suspended from the riser transition element via the tie rods and tie rod bosses. In another disclosed aspect, an apparatus comprises: a pressure vessel; a nuclear reactor core comprising fissile material disposed the pressure vessel; upper internals disposed in the pressure vessel above the nuclear reactor core, the upper internals including at least internal control rod drive mechanisms (CRDMs) with CRDM motors mounted on a suspended support assembly; a hollow cylindrical central riser disposed in the pressure vessel above the nuclear reactor core; a hollow cylindrical section disposed in the pressure vessel below the hollow cylindrical central riser and surrounding the nuclear reactor core; and a riser transition element connecting with the hollow cylindrical central riser and the hollow cylindrical section to form a continuous hollow cylindrical flow separator between a columnar hot leg flowing inside the continuous hollow cylindrical flow separator and an annular cold leg flowing in a downcomer annulus surrounding the continuous hollow cylindrical flow separator. The suspended support assembly of the upper internals is suspended from the riser transition element. In some embodiments, the pressure vessel comprises an upper vessel section and a lower vessel section connected by a mid-flange, and the riser transition element is welded to the mid-flange by gussets extending outward and upward from the riser transition element to the mid-flange. A method aspect performed in conjunction with an apparatus as set forth in the immediately preceding paragraph comprises opening the pressure vessel, and removing the riser transition element from the opened pressure vessel, the removing also simultaneously removing the upper internals which are suspended from the riser transition element. With reference to FIG. 1, a small modular reactor (SMR) 1 of the of the integral pressurized water reactor (PWR) variety is shown in partial cutaway to reveal selected internal components. The illustrative PWR 1 includes a nuclear reactor core 2 disposed in a pressure vessel comprising a lower vessel portion 3 and an upper vessel portion 4. The lower and upper vessel portions 3, 4 are connected by a mid-flange 5. Specifically, a lower flange 5L at the open top of the lower vessel portion 3 connects with the bottom of the mid-flange 5, and an upper flange 5U at the open bottom of the upper vessel portion 4 connects with a top of the mid-flange 5. The reactor core 2 is disposed inside and at or near the bottom of the lower vessel portion 3, and comprises a fissile material (e.g., 235U) immersed in primary coolant water. A cylindrical central riser 6 is disposed coaxially inside the cylindrical pressure vessel and a downcomer annulus 7 is defined between the central riser 6 and the pressure vessel. The illustrative PWR 1 includes internal control rod drive mechanisms (internal CRDMs) 8 with internal motors 8m immersed in primary coolant that control insertion of control rods to control reactivity. Guide frames 9 guide the translating control rod assembly (e.g., each including a set of control rods comprising neutron absorbing material yoked together by a spider and connected via a connecting rod with the CRDM). The illustrative PWR 1 employs one or more internal steam generators 10 located inside the pressure vessel and secured to the upper vessel portion 4, but embodiments with the steam generators located outside the pressure vessel (i.e., a PWR with external steam generators) are also contemplated. The illustrative steam generator 10 is of the once-through straight-tube type with internal economizer, and is fed by a feedwater inlet 11 and deliver steam to a steam outlet 12. See Malloy et al., U.S. Pub. No. 2012/0076254 A1 published Mar. 29, 2012 which is incorporated by reference in its entirety. The illustrative PWR 1 includes an integral pressurizer 14 at the top of the upper vessel section 4 which defines an integral pressurizer volume 15; however an external pressurizer connected with the pressure vessel via suitable piping is also contemplated. The primary coolant in the illustrative PWR 1 is circulated by reactor coolant pumps (RCPs) comprising in the illustrative example external RCP motors 16 driving an impeller located in a RCP plenum 17 disposed inside the pressure vessel. With reference to FIGS. 2 and 3, a variant PWR design 1′ is shown, which differs from the PWR 1 of FIG. 1 by having a differently shaped upper vessel section 4′ and internal RCPs 16′ in place of the external pumps 16, 17 of the PWR 1. FIG. 2 shows the pressure vessel with the upper vessel section 4′ lifted off, as is done during refueling. The mid-flange 5 remains disposed on the lower flange 5L of the lower vessel 3. FIG. 3 shows an exploded view of the lower vessel section 3 and principle components contained therein, including: the nuclear reactor core 2 comprising fuel assemblies 2′ contained in a core former 20 disposed in a core basket 22. With continuing reference to FIGS. 1 and 3 and with further reference to FIGS. 4 and 5, above the reactor core assembly 2, 20, 22 are the upper internals which include a suspended support assembly 24 comprising an upper hanger plate 30, a mid-hanger plate 32, and a lower hanger plate 34 suspended by tie rods 36 from the mid-flange 5. More particularly, in the illustrative embodiment the upper ends of the tie rods 36 are secured to a riser transition section 38 that is in turn secured with the mid-flange 5. The central riser 6 disposed in the upper vessel section 4, 4′ (shown only in FIG. 1) is connected with the core basket 22 in the lower vessel section 3 by the riser cone (not shown) and riser transition section 38 to form a continuous hollow cylindrical flow separator between the columnar hot leg of the primary coolant path flowing upward and the cold leg that flows through the downcomer annulus surrounding the hot leg. The suspended support assembly 24 comprising hanger plates 30, 32, 34 interconnected by tie rods 36 provides the structural support for the CRDMs 8 and the guide frames 9 (note the CRDMs 8 and guide frames 9 are omitted in FIG. 3). The CRDMs 8 are disposed between the upper hanger plate 30 and the mid-hanger plate 32, and are either (1) top-supported in a hanging fashion from the upper hanger plate or (2) bottom-supported on the mid-hanger plate 32 (as in the illustrative embodiments described herein). Lateral support for the CRDMs 8 is provided by both plates 30, 32. (Note that in the illustrative embodiment, the CRDMs 8 actually pass through openings of the upper hanger plate 30 so that the tops of the CRDMs 8 actually extend above the upper hanger plate 30, as best seen in FIG. 1). The guide frames 9 are disposed between the mid-hanger plate 32 and the lower hanger plate 34, and are likewise either (1) top-supported in a hanging fashion from the mid-hanger plate 32 (as in the illustrative embodiments described herein) or (2) bottom-supported on the lower hanger plate. Lateral support for the guide frames 9 is provided by both plates 32, 34. One of the hanger plates, namely the mid-hanger plate 32 in the illustrative embodiments, also includes or supports a distribution plate that includes mineral insulated cabling (MI cables) for delivering electrical power to the CRDM motors 8M and, in some embodiments, hydraulic lines for delivering hydraulic power to scram latches of the CRDMs 8. In the embodiment of FIGS. 2 and 3 (and as seen in FIG. 3), the internal RCPs 16′ are also integrated into the upper internals assembly 24, for example on an annular pump plate providing both separation between the suction (above) and discharge (below) sides of the RCPs 16′ and also mounting supports for the RCPs 16′. The disclosed upper internals have numerous advantages. The suspension frame 24 hanging from the mid-flange 5 is a self-contained structure that can be lifted out of the lower vessel section 3 as a unit during refueling. Therefore, the complex assembly of CRDMs 8, guide frames 9, and ancillary MI cabling (and optional hydraulic lines) does not need to be disassembled during reactor refueling. Moreover, by lifting the assembly 5, 24, 8, 9 out of the lower vessel 3 as a unit (e.g. using a crane) and moving it to a suitable work stand, maintenance can be performed on the components 5, 24, 8, 9 simultaneously with the refueling, thus enhancing efficiency and speed of the refueling. The tensile forces in the tie rods 36 naturally tend to laterally align the hanger plates 30, 32, 34 and thus the mounted CRDMs 8 and guide frames 9. The upper internals are thus a removable internal structure that is removed as a unit for reactor refueling. The upper internals basket (i.e., the suspension frame 24) is advantageously flexible to allow for movement during fit-up when lowering the upper internals into position within the reactor. Toward this end, the horizontal plates 30, 32, 34 are positioned at varying elevations and are connected to each other, and the remainder of the upper internals, via the tie rods 36. The design of the illustrative upper internals basket 24 is such that the control rod guide frames 9 are hung from the mid-hanger plate 32 (although in an alternative embodiment the guide frames are bottom-supported by the lower hanger plate). In the top-supported hanging arrangement, the guide frames 9 are laterally supported at the bottom by the lower hanger plate 34. The upper internals are aligned with the core former 20 and/or core basket 22 to ensure proper fit-up of the fuel to guide frame interface. This alignment is achieved by keying features of the lower hanger plate 34. With reference to FIGS. 6 and 7, alternative perspective views are shown of the hanger plates 30, 32, 34 connected by tie rods 36 and with the guide frames 9 installed, but omitting the CRDMs 8 so as to reveal the top surface of the mid-hanger plate 32. In the illustrative embodiment, a distribution plate 40 is disposed on top of the mid-hanger plate 32, as best seen in FIG. 6. The distribution plate 40 is a load-transferring element that transfers (but does not itself support) the weight of the bottom-supported CRDMs 8 to the mid-hanger plate 32. This is merely an illustrative example, and the distribution plate can alternatively be integral with the mid-hanger plate (e.g., comprising MI cables embedded in the mid-hanger plate) or located on or in the upper hanger plate. (Placement of the distribution plate in the lower hanger plate is also contemplated, but in that case MI cables would need to run from the distribution plate along the outsides of the guide frames to the CRDMs. As yet another option, the distribution plate can be omitted entirely in favor of discrete MI cables run individually to the CRDMs 8). With reference to FIG. 8, which shows a corner of the upper hanger plate 30 as an illustrative example, the tie rods 36 are coupled to each plate by tie rod couplings 42, which optionally incorporate a turnbuckle (i.e. length adjusting) arrangement as described elsewhere herein. Note that the ends of the tie rods connect with a hanger plate, with no hanger plate connecting at a middle of a tie rod. Thus, the upper tie rods 36 extend between the upper and mid-hanger plates 30, 32 with their upper ends terminating at tie rod couplings 42 at the upper hanger plate 30 and their lower ends terminating at tie rod couplings 42 at the mid-hanger plate 32; and similarly, the lower tie rods 36 extend between the mid-hanger plate 32 and the lower hanger plate 34 with their upper ends terminating at tie rod couplings 42 at the mid-hanger plate 32 and their lower ends terminating at tie rod couplings 42 at the lower hanger plate 34. With reference to FIGS. 9 and 10, the lower hanger plate 34 in the illustrative embodiment provides only lateral support for the guide frames 9 which are top-supported in hanging fashion from the mid-hanger plate 32. Consequentially, the lower hanger plate 34 is suitably a single plate with openings 50 that mate with the bottom ends of the guide frames (see FIG. 10). To simplify the alignment, in some embodiments guide frame bottom cards 52 (see FIG. 9) are inserted into the openings 50 and are connected with the bottom ends of the guide frames 9 by fasteners, welding, or another technique. (Alternatively, the ends of the guide frames may directly engage the openings 50 of the lower hanger plate 34). In addition to providing lateral support for each control rod guide frame 9, locking each in laterally with a honeycomb-type structure (see FIG. 10), the lower hanger plate 34 also includes alignment features 54 (see FIG. 10) that align the upper internals with the core former 20 or with the core basket 22. The illustrative alignment features are peripheral notches 54 that engage protrusions (not shown) on the core former 20; however, other alignment features can be employed (e.g., the lower hanger plate can include protrusions that mate with notches of the core former). Also seen in FIG. 10 are peripheral openings 56 in the lower hanger plate 34 into which the tie rod couples 42 of the lower hanger plate fit. The lower hanger plate 34 is suitably machined out of plate material or forging material. For example, in one contemplated embodiment the lower hanger plate 34 is machined from 304L steel plate stock. With continuing reference to FIGS. 6 and 7 and with further reference to FIG. 11, the mid-hanger plate 32 provides top support for the guide frames 9 and bottom support for the CRDMs 8. The mid-hanger plate 32 acts as a load distributing plate taking the combined weight of the CRDMs 8 and the guide frames 9 and transferring that weight out to the tie rods 36 on the periphery of the upper internals basket 24. In the illustrative embodiment, the power distribution plate 40 is also bottom supported. Like the lower hanger plate 34, the mid-hanger plate 32 includes openings 60. The purpose of the openings 60 is to enable the connecting rod, translating screw, or other coupling mechanism to connect each CRDM 8 with the control rod assembly driven by the CRDM. To facilitate hanging the guide frames 9 off the bottom of the mid-hanger plate 32, an egg crate-type structure made of orthogonally intersecting elements 61 is provided for increased strength and reduced deflection due to large loads. With reference to FIGS. 12 and 13, the mid-hanger plate 32 can be manufactured in various ways. In one approach (FIG. 12), a forging machining process is employed to machine the mid-hanger plate 32 out of a 304L steel forged plate 62. The machining forms the openings 60 and the intersecting elements 61. In another approach (FIG. 13), a machined plate 64 and the intersecting elements 61 are manufactured as separate components, and the intersecting elements 61 are interlocked using mating slits formed into the intersecting elements 61 and welded to each other and to the machined plate 64 to form the mid-hanger plate 32. As previously noted, the illustrative bottom-supported distribution plate 40 can alternatively be integrally formed into the mid-hanger plate. With reference to FIG. 14, in an alternative embodiment the guide frames 9 are bottom supported by an alternative lower hanger plate 34′, and are laterally aligned at top by an alternative mid-hanger plate 32′. In this case the alternative lower hanger plate 34′ may have the same form and construction as the main embodiment mid-hanger plate 32 of FIGS. 11-13 (but with suitable alignment features to align with the core former and/or core basket, not shown in FIG. 14), and the alternative mid-hanger plate 32′ can have the same form and construction as the main embodiment lower hanger plate 34 of FIG. 10 (but without said alignment features). If the CRDMs remain bottom supported, then the alternative mid-hanger plate 32′ should be made sufficiently thick (or otherwise sufficiently strong) to support the weight of the CRDMs. As another variant, the alternative mid-hanger plate 32′ can be made too thin to directly support the CRDMs, and an additional thicker upper plate added to support the weight of the CRDMs. In this case the thicker plate would be the one connected with the tie rods to support the CRDMs. In the illustrative embodiments, the guide frames 9 are continuous columnar guide frames 9 that provide continuous guidance to the translating control rod assemblies. See Shargots et al, “Support Structure for a Control Rod Assembly of a Nuclear Reactor”, U.S. Pub. No. 2012/0099691 A1 published Apr. 26, 2012 which is incorporated herein by reference in its entirety. However, the described suspended frame 24 operates equally well to support more conventional guide frames comprising discrete plates held together by tie rods. Indeed, the main illustrative approach in which the guide frames are top-supported in hanging fashion from the mid-hanger plate 32 is particularly well-suited to supporting conventional guide frames, as the hanging arrangement tends to self-align the guide frame plates. With reference to FIG. 15, an illustrative embodiment of the upper hanger plate 30 is shown. Like the other hanger plates 32, 34, the upper hanger plate 30 includes openings 70, in this case serving as passages through which the upper ends of the CRDMs 8 pass. The inner periphery of each opening 70 serves as a cam to laterally support and align the upper end of the CRDM 8. The upper hanger plate 30 can also suitably be made by machining from either plate material or forging material, e.g. a 304L steel plate stock or forging. With reference to FIGS. 16-18, the tie bar (alternatively “tie rod”) couplings 42 are further described. FIG. 16 shows the suspended frame 24 including the upper, mid-, and lower hanger plates 30, 32, 34 held together by tie rods 36. For clarity, the tie bars are denoted in FIG. 16 as upper tie bars 361 and lower tie bars 362, and the various levels of tie bar couples are denoted as upper tie bar couples 421, middle tie bar couples 422, and lower tie bar couples 423. At the upper end, short tie rods (i.e. tie rod bosses) 36B have upper ends welded to the riser transition 38 and have lower ends threaded into the tops of upper tie bar couplings 421. The upper tie bars 361 have their upper ends threaded into the bottoms of upper tie bar couplings 421 and have their lower ends threaded into the tops of middle tie bar couplings 422. The lower tie bars 362 have their upper ends threaded into the bottoms of middle tie bar couplings 422 and have their lower ends threaded into the tops of lower tie bar couplings 423. FIGS. 17 and 18 show perspective and sectional perspective views, respectively, of the middle tie bar coupling 422. As best seen in FIG. 18, the tie rod coupling 422 has a turnbuckle (i.e. length adjusting) configuration including outer sleeves 81, 82 having threaded inner diameters that engage (1) the threaded outsides of the ends of the respective mating tie rods 361, 362, and (2) the threaded outsides of a plate thread feature 84. Thus, by rotating the outer sleeve 81 the position of tie rod 361 respective to the mid-hanger plate 32 can be adjusted; and similarly, by rotating the outer sleeve 82 the position of tie rod 362 respective to the mid-hanger plate 32 can be adjusted. (Note that the plate thread feature 84 can be a single element passing through the mid-hanger plate 32, or alternatively can be upper and lower elements extending above and below the mid-hanger plate 32, respectively). The tie bar coupling 421 is the same as tie bar coupling 422 except that the upper outer sleeve 81 suitably engages the tie rod boss 36B; while, the tie bar coupling 42 is the same as tie bar coupling 422 but omits the lower half (i.e. lower outer sleeve 82 and the corresponding portion of the plate thread feature 84), since there is no tie rod “below” for the tie bar coupling 423 to engage. Said another way, the tie rod coupling portions 81, 82 can be threaded on their inner diameter with threads matching that of the outer diameter of the tie rods 36 and on the threading feature 84 of any of the plates 30, 32, 34 or riser transition 38. This allows the coupling 42 to be threaded onto the tie rod 36 and onto the threading feature 84 of any other component. The advantages to a coupling such as this is that a very accurate elevation can be held with each of the above mentioned components 30, 32, 34, 38 within the upper internals, and that each of the above components can hold a very accurate parallelism with one another. Essentially, the couplings allow for very fine adjustments during the final assembly process. They also allow for a quick and easy assembly process. Another advantage to the couplings 42 is that they allow for the upper internals to be separated at the coupling joints fairly easily for field servicing or decommissioning of the nuclear power plant. In an alternative tie rod coupling approach, it is contemplated for the tie rods to be directly welded to any of the plates or riser transition, in which case the tie rod couplings 42 would be suitably omitted. However, this approach makes it difficult to keep the tie rod perpendicular to the plates making assembly of the upper internals more difficult. It also makes breaking the upper internals down in the field more difficult. With reference to FIG. 19, the riser transition 38 is shown in perspective view. The riser transition assembly 38 performs several functions. The riser transition 38 provides load transfer from the tie rods 36 of the upper internals basket 24 to the mid-flange 5 of the reactor pressure vessel. Toward this end, the riser transition 38 includes gussets 90 by which the riser transition 38 is welded to the mid-flange 5. (See also FIGS. 4 and 5 showing the riser transition 38 with gussets 90 welded to the mid-flange 5). One or more of these gussets 90 may include a shop lifting lug 91 or other fastening point to facilitate transport, for example when the upper internals are lifted out during refueling. The load transfer from the tie rods 36 to the mid-flange 5 is mostly vertical loading due to the overall weight of the upper internals. However, there is also some radial differential of thermal expansion between the riser transition gussets 90 and the mid-flange 5, and the riser transition 38 has to also absorb these thermal loads. As already mentioned, the riser cone and riser transition 38 also acts (in conjunction with the central riser 6 and core basket 22) as the flow divider between the hot leg and cold leg of the primary coolant loop. Still further, the riser transition 38 also houses or includes an annular hydraulic collection header 92 for supplying hydraulic power via vertical hydraulic lines 94 to the CRDMs (in the case of embodiments employing hydraulically driven scram mechanisms). The riser transition 38 also has an annular interface feature 96 for fit-up with the riser cone or other connection with the central riser 6, and feature cuts 98 to allow the passing of the CRDM electrical MI cable. With brief returning reference to FIGS. 4 and 5, the gussets 90 are suitably welded to the mid-flange 5 at one end and welded to the main body portion 37 of the riser transition assembly 38 at the other end. The riser transition 38 if suitably made of 304L steel, in some embodiments, e.g. by machining from a ring forging. With reference to FIG. 20, an illustrative gusset 90 is shown, having a first end 100 that is welded to the mid-flange 5 and a second end 102 that is welded to the riser transition 38 as already described. The gusset 90 includes horizontal cantilevered portion 104, and a tensile-strained portion 106 that angles generally downward, but optionally with an angle A indicated in FIG. 20. The horizontal cantilevered portion 104 has a thickness dcant that is relatively greater than a thickness dG of the tensile-strained portion 106. The thicker cantilevered portion 104 handles the vertical loading component, while the tensile-strained portion 106 allows the gusset 90 to deflect in the lateral direction to absorb lateral loading due to thermal expansion. The angle A of the tensile-strained portion 106 provides for riser cone lead-in. The end 102 of the gusset 90 that is welded to the riser transition 38 includes an upper ledge 108 that serves as a riser cone interface. In the illustrative embodiments, the CRDMs 8 are bottom supported from the mid-hanger plate 32, and the tops of the CRDMs 8 are supported by the upper hanger plate 30, which serves as the lateral support for each CRDM, locking each in laterally with a honeycomb type structure (see FIG. 15). Even with this support structure, however, the CRDM 8 should be protected during an Operating Basis Earthquake (OBE) or other event that may cause mechanical agitation. To achieve this, it is desired to support the upper end of the CRDM to prevent excessive lateral motion and consequently excessive loads during an OBE. It is disclosed to employ a restraining device which still allows for ease of maintenance during an outage. Using spring blocks integrated into the CRDM 8 satisfies both of these requirements, as well as providing compliance that accommodates any differential thermal expansion. Integrating compliance features into support straps of the CRDM 8 allows the CRDM's to be removed while still maintaining lateral support. As the CRDM is lowered into its mounting location the compliant features come into contact with the upper hanger plate 30. The compliance allows them to maintain contact with the upper hanger plate yet allow for misalignment between the CRDM standoff mounting point and the upper hanger plate. Their engagement into the upper hanger plate 30 allows them to be of sufficient height vertically from the mounting base of the CRDMs to minimize the loads experienced at the base in an OBE event. Having no feature that extends below the upper hanger plate allows the CRDM to be removed from the top for service. With reference to FIGS. 21 and 22, an upper end of a CRDM 8 includes a hydraulic line 110 delivering hydraulic power to a scram mechanism. Straps 112, 114 secure the hydraulic line 110 to the CRDM 8. The strap 114 is modified to include compliance features 116. As seen in FIG. 22, the compliance features 116 comprise angled spring blocks that wedges into the opening 70 of the upper hanger plate 30 when the CRDM 8 is fully inserted. It will be appreciated that such compliance features 116 can be incorporated into straps retaining other elements, such as electrical cables (e.g. MI cables). The illustrative compliance features 116 can be constructed as angled leaf springs cut into the (modified) strap 114. Alternatively, such leaf springs can be additional elements welded onto angled ends of the strap 114. By including such springs on straps 114 on opposite sides of the CRDM 8, four contact points are provided to secure the CRDM against lateral motion in any direction. The wedged support provided by the straps 114 also leave substantial room for coolant flow through the opening 70 in the upper hanger plate 30. The disclosed embodiments are merely illustrative examples, and numerous variants are contemplated. For example, the suspended frame of the upper internals can include more than three plates, e.g. the power distribution plate could be a separate fourth plate. In another variant, the mid-hanger plate 32 could be separated into two separate hanger plates—an upper mid-hanger plate bottom-supporting the CRDMs, and a lower mid-hanger plate from which the guide frames are suspended. In such a case, the two mid-hanger plates would need to be aligned by suitable alignment features to ensure relative alignment between the CRDMs and the guide frames. The use of at least three hanger plates is advantageous because it provides both top and bottom lateral support for both the CRDMs and the guide frames. However, it is contemplated to employ only two hanger plates if, for example, the bottom support of the CRDMs is sufficient to prevent lateral movement of the CRDMs. In the illustrative embodiments, the suspended support assembly 24 is suspended from the mid-flange 5 via the riser transition 38. However, other anchor arrangements are contemplated. For example, the suspended support assembly could be suspended directly from the mid-flange, with the riser transition being an insert secured to the gussets. The mid-flange 5 could also be omitted. One way to implement such a variant is to include a ledge in the lower vessel on which a support ring sits, and the suspended support assembly is then suspended from the support ring. With the mid-flange 5 omitted, the upper and lower flanges 5U, 5L of the upper and lower vessel sections can suitably connect directly (i.e., without an intervening mid-flange). Instead of lifting the upper internals out by the mid-flange 5, the upper internals would be lifted out by the support ring. In the embodiment of FIGS. 2 and 3, the internal RCPs 16′ are incorporated into the upper internals and are lifted out with the upper internals. Other configurations are also contemplated—for example, internal RCPs could be mounted in the upper vessel and removed with the upper vessel. The preferred embodiments have been illustrated and described. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the invention be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
	description	This application claims the benefit of U.S. Provisional Application No. 62/330,726, filed May 2, 2016, which application is hereby incorporated by reference. This application is a divisional of U.S. patent application Ser. No. 15/584,659, titled “Molten Fuel Reactor Thermal Management Configurations”, filed May 2, 2017, now abandoned. The utilization of molten fuels in a nuclear reactor to produce power provides significant advantages as compared to solid fuels. For instance, molten fuel reactors generally provide higher power densities compared to solid fuel reactors, while at the same time having reduced fuel costs due to the relatively high cost of solid fuel fabrication. Molten fluoride fuel salts suitable for use in nuclear reactors have been developed using uranium tetrafluoride (UF4) mixed with other fluoride salts such as UF6, and UF3. Molten fluoride salt reactors have been operated at average temperatures between 600° C. and 860° C. Binary, ternary, and quaternary chloride fuel salts of uranium, as well as other fissionable elements, have been described in co-assigned U.S. patent application Ser. No. 14/981,512, titled MOLTEN NUCLEAR FUEL SALTS AND RELATED SYSTEMS AND METHODS which application is hereby incorporated herein by reference. In addition to chloride fuel salts containing one or more of PuCl3, UCl4, UCl3F, UCl3, UCl2F2, and UClF3, the application further discloses fuel salts with modified amounts of 37Cl, bromide fuel salts such as UBr3 or UBr4, thorium chloride (e.g., ThCl4) fuel salts, and methods and systems for using the fuel salts in a molten fuel reactor. Average operating temperatures of chloride salt reactors are anticipated between 300° C. and 600° C., but could be even higher, e.g., >1000° C. This disclosure describes various configurations and components of a molten fuel nuclear reactor. For the purposes of this application, embodiments of a molten fuel reactor that use a chloride fuel, such as a mixture of one or more fuel salts such as PuCl3, UCl3, and/or UCl4 and one or non-fissile salts such as NaCl and/or MgCl2, will be described. However, it will be understood that any type of fuel salt, now known or later developed, may be used and that the technologies described herein may be equally applicable regardless of the type of fuel used. For example, a fuel salt may include one or more non-fissile salts such as, but not limited to, NaCl, MgCl2, CaCl2, BaCl2, KCl, SrCl2, VCl3, CrCl3, TiCl4, ZrCl4, ThCl4, AcCl3, NpCl4, AmCl3, LaCl3, CeCl3, PrCl3 and/or NdCl3. Note that the minimum and maximum operational temperatures of fuel within a reactor may vary depending on the fuel salt used in order to maintain the salt within the liquid phase throughout the reactor. Minimum temperatures may be as low as 300-350° C. and maximum temperatures may be as high as 1400° C. or higher. Similarly, except were explicitly discussed otherwise, heat exchangers will be generally presented in this disclosure in terms of simple, single pass, shell-and-tube heat exchangers having a set of tubes and with tube sheets at either end. However, it will be understood that, in general, any design of heat exchanger may be used, although some designs may be more suitable than others. For example, in addition to shell and tube heat exchangers, plate, plate and shell, printed circuit, and plate fin heat exchangers may be suitable. FIG. 1 illustrates, in a block diagram form, some of the basic components of a molten fuel reactor. In general, a molten fuel reactor 100 includes a reactor core 104 containing a fissionable fuel salt 106 that is liquid at the operating temperature. Fissionable fuel salts include salts of any nuclide capable of undergoing fission when exposed to low-energy thermal neutrons or high-energy neutrons. Furthermore, for the purposes of this disclosure, fissionable material includes any fissile material, any fertile material or combination of fissile and fertile materials. The fuel salt 106 may or may not completely fill the core 104, and the embodiment shown is illustrated with an optional headspace 102 above the level of the fuel salt 106 in the core 104. The size of the reactor core 104 may be selected based on the characteristics and type of the particular fuel salt 106 being used in order to achieve and maintain the fuel in an ongoing state of criticality, during which the heat generated by the ongoing production of neutrons in the fuel causes the temperature of the molten fuel to rise when it is in the reactor core. Criticality refers to a state in which loss rate of neutrons is equal to or less than the production rate of neutrons in the reactor core. The performance of the reactor 100 is improved by providing one or more reflectors 108A, 108B, 108C around the core 104 to reflect neutrons back into the core. Reflectors may be made of any neutron reflecting material, now known or later developed, such as graphite, beryllium, steel, tungsten carbide. The molten fuel salt 106 is circulated between the reactor core 104 and one or more primary heat exchangers 110 located outside of the core 104. The circulation may be driven using one or more pumps 112. The primary heat exchangers 110 transfer heat from the molten fuel salt 106 to a primary coolant 114 that is circulated through a primary coolant loop 115. In an embodiment the primary coolant may be another salt, such as NaCl—MgCl2, or lead. Other coolants are also possible including Na, NaK, supercritical CO2 and lead bismuth eutectic. In an embodiment, a reflector 108 is between each primary heat exchanger 110 and the reactor core 104 as shown in FIG. 1. For example, in an embodiment a cylindrical reactor core 104, having a diameter of 2 meters (m) and a height of 3 m, is oriented vertically so that the flat ends of the cylinder are on the top and bottom respectively. The entire reactor core 104 is completely encased in reflectors 108 between which are provided channels for the flow of fuel salt 106 into and out of the reactor core 104. Although FIG. 1 illustrates one heat exchanger 110, depending on the embodiment any number of heat exchangers 110 may be used, the heat exchangers 110 being spaced around the exterior of the core 104. For example, embodiments having two, four, six, eight, ten, twelve and sixteen primary heat exchangers are contemplated. As discussed above, any design of heat exchanger may be used but, generally, the heat exchangers 110 will be discussed in terms of a shell and tube heat exchanger. In shell and tube heat exchanger embodiments, the fuel salt may flow through the tubes which are contained within a shell filled with the primary coolant. The fuel salt enters the tubes via one or more tube sheets in the shell to prevent the fuel salt from mixing with the primary coolant. This is referred to as either a tube-side fuel or a shell-side coolant configuration. Alternatively, the fuel salt may flow through the shell and the primary coolant may flow through the tubes, which is referred to either as a tube-side coolant or shell-side fuel configuration. Salt contacting surfaces of heat exchanger components may be clad to protect against corrosion. Other protection options include protective coatings, loose fitting liners or press-fit liners. In an embodiment, cladding on the internal surface of the tubes is molybdenum that is co-extruded with the base heat exchanger tube material. For other fuel salt contacting surfaces (exterior surfaces of the tube sheets and exterior surface of the shell), the cladding material is molybdenum alloy. Nickel and nickel alloys are other possible cladding materials. Molybdenum-rhenium alloys may be used where welding is required. Components in contact with primary cooling salt may be clad with Alloy 200 or any other compatible metals, such as materials meeting the American Society of Mechanical Engineers' pressure vessel code. The tube primary material may be 316 stainless steel or any other compatible metals. For example, in an embodiment alloy 617 is the shell and tube sheet material. In a tube-side fuel embodiment the fuel salt flows through the tubes of the heat exchanger 110 and exits into the fuel salt outlet channel. The primary coolant within the shell of the heat exchanger 110 removes heat from the fuel salt traveling through the tubes and heated coolant is then passed to the power generation system 120. As shown in FIG. 1, heated primary coolant 114 from the primary heat exchangers 110 is passed to a power generation system 120 for the generation of some form of power, e.g., thermal, electrical, or mechanical. The reactor core 104, primary heat exchangers 110, pumps 112, molten fuel circulation piping (including other ancillary components that are not shown such as check valves, shutoff valves, flanges, drain tanks, etc.) and any other components through which the molten fuel circulates or contacts during operation can be referred to as the fuel loop 116. Likewise, the primary coolant loop 115 includes those components through which primary coolant circulates, including the primary heat exchangers 110, primary coolant circulation piping (including other ancillary components that are not shown such as coolant pumps 113, check valves, shutoff valves, flanges, drain tanks, etc.). The molten fuel reactor 100 further includes at least one containment vessel 118 that contains the fuel loop 116 to prevent a release of molten fuel salt 106 in case there is a leak from one of the fuel loop components. Note that not all of the primary coolant loop 115 is within the containment vessel 118. In an embodiment fuel salt flow is driven by a pump 112 so that the fuel salt circulates through the fuel loop 116. In the embodiment shown, there is one pump 112 for each primary heat exchanger 110. Fewer or more pumps may be used. For example, in alternative embodiments multiple, smaller pumps may be used for each heat exchanger 110. In an embodiment, a pump 112 may include an impeller at some location within the fuel loop 116 that when rotated drives the flow of fuel salt around the fuel loop. The impeller may be attached to a rotating shaft that connects the impeller to a motor which may be located outside of the containment vessel. An example of this embodiment can be found in FIGS. 6A-6C, discussed below. Other pump configurations are also possible. Broadly speaking, this disclosure describes multiple alterations and component configurations that improve the performance of the reactor 100 described with reference to FIG. 1. Frustoconical Reactor Core Configuration In typical fuel salts, higher temperature molten salt is less dense than lower temperature salt. For example, in one fuel salt (71 mol % UCl4-17 mol % UCl3-12 mol % NaCl) for a 300° C. temperature rise (e.g., 627° C. to 927° C.), the fuel salt density was calculated to fall by 18%, from 3660 to 3010 kg/m3. In an embodiment, it is desirable that the reactor core and primary heat exchanger be configured such that fuel circulation through the fuel loop can be driven by the density differential created by the temperature difference between the higher temperature salt in the core and the lower temperature salt elsewhere in the fuel loop 116. This circulation may be referred to as natural circulation as the circulation flow occurs naturally as a result of the density differences in the fuel salt during steady state operation. FIGS. 2A-2C illustrate an embodiment of a reactor that uses only natural circulation to circulate fuel salt around the fuel loop. This configuration can obviate the need for fuel salt pumps and no pumps are shown. This reduces the complexity of the reactor 200, however, relying solely on natural circulation may limit the amount of heat that can be removed and, thus, limit the total power output of the reactor 200. FIG. 2A illustrates a reactor 200 that includes a roughly cylindrical reactor core 204, which is a volume defined by, a upper reflector 208A at the top, a lower reflector 208B at the bottom, and a lateral or inner reflector 208C that rings the circumference of the core. As with FIG. 1, flow paths are provided at the top and the bottom of the reactor core 204 to allow the fuel salt to flow around the lateral reflector 208C. In this natural circulation embodiment, heated fuel salt flows over the top the lateral reflector 208C to the heat exchanger(s) 210 during steady state fission. The fuel salt then circulates downward through the heat exchanger(s) 210 and cooled fuel salt returns to the reactor core 204 via one or more flow paths between the bottom reflector 208B and the lateral reflector 208C. In the embodiment shown, the lateral reflector 208B is provided with a flow guide shaped as a bulge below the heat exchanger 210 that constricts the cooled fuel salt flow path back into the reactor core 204. Any type of flow guide shape may be used. FIG. 2B is a cross-sectional view of half of the reactor of FIG. 2A showing the flow paths for the fuel salt. In the embodiment shown, for modeling purposes the reactor core 204 is 1 meter (m) in radius with a height of 3 m. Solid upper and lower bottom reflectors 208A, 208B define the upper and lower extents of the fuel salt. The spaces between the reflectors create flow paths, which may alternately be referred to as channels or ducts, allowing the circulation of fuel salt from the reactor core over the inner reflector, through the primary heat exchanger, under the inner reflector, and back into the bottom of the reactor core. One or more flow directing baffles or guide vanes may be provided in the fuel salt ducts of the fuel loop in order to obtain a more uniform flow and equally distribute the flow of fuel salt through the fuel loop and to reduce stagnant zones in the fuel loop. Fuel salt heated in the core will buoyantly rise and flow around the inner reflector 208C, through the heat exchanger 210, then through the return channel defined by the bulging shape of the inner reflector 208C and the lower reflector 208B. In an embodiment, the reflectors may be lead filled vessels and the guide structures (e.g., vanes 212) are solids with thermal properties of stainless steel. The contouring and guide structures illustrated are provided to promote good flow at the inlet of the heat exchanger and reduce the occurrence and impact of recirculation cells within the fuel loop. FIG. 2C illustrates temperature and flow modelling results for the embodiment shown in FIG. 2B under a set of representative operating conditions for a representative fuel salt (71 mol % UCl4-17 mol % UCl3-12 mol % NaCl). From the modeling, it was found that the highest temperature was approximately 1150° C. at the top of the center of the core 204 and the lowest temperature was about 720° C. at the outlet of the heat exchanger 210. The temperature results indicate that, under the conditions of the model, a natural circulation cell is created in which the dense, cool fuel salt flows into the bottom of the reactor core 204 thereby displacing the lighter, hot fuel salt into the heat exchanger 210. The ongoing fission in the center of the core 204 reheats the cooled fuel salt and drives the circulation cell until the fission is interrupted, for example by the introduction of a moderator or degradation of the fuel salt. In an alternative embodiment a reactor may use both pumps and natural circulation to move the fuel salt through the fuel loop during normal power-generating operation. Natural circulation is still beneficial, in such an embodiment, both in reducing the size of the pumps needed to achieve a target flow rate and in the event of a loss of power to the pump or pumps because the circulation, and thus the cooling, will continue even without the active pumping fuel salt through the fuel loop. One method of increasing the strength of natural circulation is through selectively locating the high temperature reactor core 204 below the primary heat exchanger 210. This enhances the effect of the density differential on the circulation by locating the densest salt, e.g., the cooled salt output by the primary heat exchanger, at a location in the fuel loop 116 physically above the highest temperature (thus least dense) salt, which can be found at the “thermal center” of the reactor core. For the purposes of this disclosure, the “thermal center” refers to that location within the reactor core, based on the shape and size of the core, where the most heat is generated by the ongoing nuclear fission reactions in the reactor core, in the absence of flow through the reactor. This point is identified in FIG. 2B, located at the center of the cylindrical reactor core, both vertically and horizontally. In a subcritical homogenous fuel salt, the location of the thermal center due to decay heat can be approximated by using the center of mass of the fuel salt volume defined by the reactor core 204. This is just an approximation, however, as the configuration and shape of the reflectors 208 and other components will have some impact on the fission reaction within the reactor core 204, and thus the location of the thermal center. In its most simple embodiment (not shown), a reactor designed to use natural circulation can locate the primary heat exchanger completely above the reactor core. However, this vertically stacked design is complicated by the generation of gases in the fuel salt during nuclear fission as well as potentially requiring a larger containment vessel. The evolution of gases into the heat exchanger increases the chance of vapor lock of the exchanger and generally increases the complexity and reduces the efficiency of the heat exchanger. For that reason, reactors with heat exchangers at or below the typical working surface level of the salt in the reactor core have certain benefits. FIG. 3 illustrates an embodiment of an improved configuration for a naturally circulating fission reactor core in which the reactor core is larger at the bottom than at the top. In the embodiment shown, the reactor core 304 has a roughly frustoconical shape. Frustoconical refers to the shape of a cone with the tip truncated by a plane parallel to the cone's base. FIG. 3 is a cross sectional view of half of the reactor core 300 similar to that of FIGS. 2A-2C. The reactor core 304 is surrounded by an upper reflector 308A, a lower reflector 308B and an inner reflector 308C that separates the reactor core from the primary heat exchanger 310. As with the reactor in FIG. 2B, there is no headspace and the entire reactor, i.e., reactor core 304, channels, and primary heat exchanger 310 is filled with fuel salt. The spaces between the reflectors 308A, 308B, 308C create channels allowing the circulation of fuel salt from the reactor core 304 over the inner reflector 308C, through the primary heat exchanger 310, under the inner reflector 308C, and back into the bottom of the reactor core 304. The frustoconical shape has the effect of moving the center of mass and, thus, the thermal center 324 of the fuel salt lower in the reactor core 304 and requires that the thermal center be below midpoint between the top and the bottom of the reactor core. Given a fixed location of the primary heat exchangers relative to the reactor core, this change to a shape in which the bottom of the reactor core is larger than the top, as occurs in a frustum of a cone or pyramid, will improve the natural circulation of the fuel salt in the fuel loop. FIG. 4 illustrates another embodiment of a frustoconical reactor core design. FIG. 4 is a cross sectional view of half of the reactor core 400 similar to that of FIGS. 2A-2C and 3. The reactor core 404 is surrounded by an upper reflector 408A, a lower reflector 408B and an inner reflector 408C that separate the reactor core from a vertically-oriented primary heat exchanger 410. The spaces between the reflectors 408A, 408B, 408C create channels allowing the circulation of fuel salt from the reactor core 404 over the inner reflector 408C, through the primary heat exchanger 410, under the inner reflector 408C, and back into the bottom of the reactor core 404. Again, the frustoconical shape has the effect of moving the center of mass and the thermal center 424 of the fuel salt lower in the reactor core. FIGS. 2A-2C, 3 and 4 are drawn roughly to the same scale and a comparison of the three illustrates the difference in approximate locations of their respective thermal centers. In FIG. 2B, the thermal center is approximately at the center of the reactor core which is almost level to the bottom of the primary heat exchanger. In FIGS. 3 and 4, the thermal centers are located significantly lower in the reactor core and clearly below the bottom of the primary heat exchanger. By bottom of the heat exchanger, it is meant the location where the coldest molten salt will be in the system, which is the outlet of the heat exchanger. For example, in a shell-and-tube heat exchanger, the bottom of the heat exchanger will be at the lower tube sheet. By using a reactor core that is larger at the bottom than at the top as shown in FIGS. 3 and 4, for any given heat exchanger configuration in which the top of the heat exchanger is level with or below the fuel salt level in the reactor core, the location of the thermal center relative to the location of the coldest fuel salt in the circulation loop can be altered. This further allows the amount of natural circulation to be controlled. In an embodiment, one performance factor that determines the strength of the natural circulation in a reactor is the ratio of the vertical distance, A, between the top and bottom of the reactor core, that is the depth of salt in the reactor core, (identified as distance A in FIGS. 3 and 4) and the distance below the bottom of the heat exchanger of the thermal center of the reactor core (identified as distance B in FIGS. 3 and 4). In an embodiment, the ratio of B/A is positive, that is the thermal center is below the bottom of the heat exchanger. The larger the ratio of B/A is, the stronger the natural circulation cell will be. In an embodiment, the ratio of B/A is between 0.01 and 0.45. In yet another embodiment, the ratio is between 0.1 and 0.4. Reactor cores shaped as the frustum of a cone are but one example of a reactor core shape that is larger at the bottom than the top and that, therefore, enhances the natural circulation through a primary heat exchanger. Other shapes are possible, especially since the shape of the reactor core is essentially defined by the upper, lower and internal reflectors. For example, the frustum need not be exactly conical, but could be a frustum of a pyramid having any number of planar or curved sides, e.g., a 3-sided pyramid, a 4-sided (or square) pyramid, a 5-sided (or pentagonal) pyramid, a 6-sided (or hexagonal) pyramid, and so on up to any number sides of a pyramid, each having a truncated tip. FIG. 5, for example, illustrates a frustum of a decagonal pyramid (10-sided pyramid), which would be a suitable shape for a naturally circulating reactor core. In addition, the shape need not be axially symmetrical. That is, a reactor core could be shaped as a trapezoidal prism having a base, a top, one set of parallel vertical sides and an opposing set of sloping planar sides. In yet another alternative some of the prism's sides could be curved instead of planar. The reactor core also could be shaped as a hyperboloid, as with the commonly observed cooling towers at some nuclear facilities, or irregularly shaped. Any such frustum shape is suitable as long as the area of the base of the reactor core is larger than the area of the top or the majority of the mass of the fuel salt is below the midpoint between the top and bottom of the reactor core so that the thermal center is lower than the midpoint between the level of fuel salt in the reactor core and the bottom of the reactor core. In combination with a heat exchanger having an inlet at or below the level of fuel salt in the reactor core and an outlet above the thermal center, the frustum-shaped reactor core significantly improves the natural circulation of the fuel salt during power-generating operation over a cylinder-shaped core of the same height. Integrated Active Vessel Cooling FIGS. 6A-6C illustrate an embodiment of a reactor design that integrates active cooling of the containment vessel into the primary coolant loop. FIG. 6A illustrates a perspective view of an eight-exchanger configuration of a molten salt reactor 600 partially cutaway to show different internal components. FIG. 6B is a cross-sectional view through the center of the reactor and two opposing heat exchangers. FIG. 6C is a cross-sectional view in perspective showing more detail about the heat exchanger design and the routing of the primary coolant. In the FIGS. 6B and 6C, brackets are provided to show the sections of the containment vessel 618 that are subjected to active cooling due to coolant or fuel salt flow. In the embodiment shown, the reactor core 604 and heat exchangers 610 are within a containment vessel 618. The primary containment vessel 618 is defined by a liner or set of liners that create an open-topped vessel. The cooled primary coolant enters and exits the vessel 618 from the top, which allows the containment vessel to be unitary and have no penetrations. The primary coolant loop is integrated into the reactor 600 so that the entering primary coolant first cools at least a portion of the containment vessel 618. After being routed next to an interior surface of the containment vessel 618 for some distance in a primary coolant inlet channel 630, in the embodiment shown the coolant is then routed into the bottom of the primary heat exchanger 610. The coolant exits the top of the primary heat exchanger 610 and is then routed out of the containment vessel 618 and to a power generation system (not shown). In the embodiment shown fuel salt is driven through the fuel loop eight separate impellers 612A located above the heat exchangers 610. Each impeller 612A is connected by a rotating shaft 612B to a motor (not shown) located above the reactor 600. The flow of the salt through the fuel loop is shown by dashed line 606 while flow of the primary coolant is shown by dotted line 614. Another aspect of the illustrated design is that the cooled fuel salt exiting the heat exchangers 610 is routed along a portion of the containment vessel prior to entering the reactor core 604. This integrates additional active cooling into the containment vessel. As the embodiment illustrates, the containment vessel is not immediately adjacent to the reactor core at any point. In fact, the containment vessel 618 of FIGS. 6A-6C is immediately adjacent to only three components: the inlet channel 630 for cooled primary coolant, the cooled fuel salt channel 632 that returns cooled salt to the reactor core 604, and the lower reflector 608B. Note also that the lower reflector 608B itself is cooled by the flow of cooled fuel salt entering the reactor core 604, which then indirectly cools the portion of the containment vessel 618 adjacent to the lower reflector. Thus, the containment vessel 618 is only adjacent to components that have been actively cooled by contact with either the cooled primary coolant or the cooled fuel salt. In operation, the primary coolant loop not only serves to remove heat from the molten fuel salt, but also directly removes heat from, and maintains the temperature of, the containment vessel. Note that the system as illustrated allows for independent control of both the fuel temperature and containment vessel temperature through the independent control of the flow of fuel salt and of the primary coolant. By modulating the two flows, the operator may be able to selectively maintain both the core temperature and the containment vessel temperature at independent levels. In addition, by routing the flows and providing insulation at various locations, the heat transfer characteristics between different components may be tailored to provide more or less cooling as needed. FIG. 7 is a flow diagram of an embodiment of a method for active vessel cooling. In the embodiment shown, integrated active cooling may be considered as a method 700 for actively cooling a containment vessel in a molten fuel salt nuclear reactor by removing heat directly from both the molten salt and at least a portion of the containment vessel via a primary coolant loop. In a first direct containment vessel cooling operation 702, at least a first portion of the containment vessel is cooled by the primary coolant, before the coolant enters the fuel salt heat exchanger proper. This is achieved by routing cooled primary coolant adjacent to an inside surface of at least a portion of the containment vessel prior to routing it into a primary heat exchanger. This serves to actively cool that portion of the containment vessel. In an embodiment, the coolant inlet channel and its thermal contact to the containment vessel in this portion may be designed to enhance the heat transfer between the coolant and the vessel. The first direct containment vessel cooling operation 702 may also include cooling the reactor head by routing the primary coolant through the reactor head. In an embodiment, this routing may be used to specifically cool the upper reflector of the reactor. This may be done using the same coolant that then flows to the heat exchanger, a side stream of coolant that is then combined with the main coolant stream, or using a completely separate coolant stream. In the embodiment shown, in a second direct containment vessel cooling operation 704 at least a second portion of the containment vessel is cooled by the cooled fuel salt exiting the primary heat exchanger before the cooled fuel salt enters the reactor core. This may be achieved by routing the cooled fuel salt adjacent to an interior surface of the second portion of the containment vessel as shown in FIGS. 6A-6C. Similar to the coolant inlet channel, the cooled fuel salt channel and its thermal contact to the containment vessel in this portion may be designed to enhance the heat transfer between the cooled fuel salt and the vessel. A third indirect cooling operation 706 may be performed, as well. In the third operation the cooled fuel salt may be routed adjacent to a surface of a neutron reflector that is in contact with some third portion of the containment vessel, thereby cooling the neutron reflector and, indirectly, the third portion of the containment vessel in contact with the neutron reflector. In this operation 706, depending on the embodiment, the reflector may be a lower reflector such as reflector 608B as shown in FIGS. 6A-6C, or a lateral reflector that is adjacent to a portion of the containment vessel. Shell-Side Fuel Configuration of Primary Heat Exchanger Where described in any detail above, primary heat exchangers have been discussed in terms of shell and tube heat exchangers with the fuel salt flowing through the tubes and primary coolant flowing through the shell and around the tubes. As mentioned, this may be referred to as a “tube-side fuel” or “shell-side coolant” configuration, alternatively. However, an improvement in the overall operation of the reactor may be obtained by moving to a shell-side fuel configuration. It has been determined that in an environment where metal components are exposed to high doses of radiation over long periods of time, it is more difficult to predict the degradation of welded components than of the unwelded material. Welds are weak and potentially subject to radiation damage and degradation over time at high doses. Thus, to reduce risk and increase the level of predictability inherent in a particular design, it is helpful to move welded components as far away as possible from the high neutron flux regions or eliminate welded components from the design altogether. One welded component that is difficult to eliminate are tube sheets in shell and tube heat exchangers. As the welds in the tube sheets prevent the mixing of the fuel salt with the primary coolant, the reduction of degradation of the welds over time is a design factor. An improvement in the reactor design is to switch the heat exchanger design to a shell-side fuel design and move the opposing tube sheets as far from the center of the reactor core as possible while remaining within the containment vessel. This reduces the relative dose received by the tube sheets in comparison to the designs in FIGS. 2A-2C, 3, 4, and 6A-6C. FIG. 8 illustrates an embodiment of a reactor with a shell-side fuel heat exchanger configuration. In the embodiment, half of the reactor 800 is illustrated as in FIGS. 4A-6. The reactor core 804 is surrounded by an upper reflector 808A, a lower reflector 808B and an inner reflector 808C that separates the reactor core from the primary heat exchanger 810. The spaces between the reflectors 808A, 808B, 808C create channels allowing the circulation of fuel salt (illustrated by a dashed line 806) from the reactor core 804 over the inner reflector 808C, through the shell side of the primary heat exchanger 810, under the inner reflector 808C, and back into the bottom of the reactor core 804. Baffles 812 are provided in the shell to force the fuel salt to follow a circuitous path around the tubes of the heat exchanger. Coolant flows through the tube-side of the heat exchanger 810, but before entering the bottom of the heat exchanger first flows down the length of a coolant inlet channel 830 adjacent to the side wall and a portion of the bottom of the containment vessel 818. Thus, the reactor 800 shown uses an embodiment of the active cooling method 700 described above with reference to FIG. 7 in which a portion of the reactor vessel 818 is directly cooled by the cool primary coolant and the lower reflector 808B is directly cooled by the cool fuel salt returning to the reactor core 804. The primary coolant enters the tubes of the heat exchanger 810 by flowing through the lower tube sheet 831, which is illustrated as being level with the bottom of the reactor core. The lower tube sheet 831 may be at or below the level of the lower reflector 808B depending on the embodiment. The coolant exits the tubes of the heat exchanger at the upper tube sheet 832, which is located in FIG. 8 some distance above the reactor core 804 and containment vessel 818. The flow of the coolant is also illustrated by a dashed line 814. FIG. 8 illustrates a region 834 within the shell of the heat exchanger that is above the level of salt in the reactor core 804. This region may either be solid, except for the penetrating tubes, or may be a headspace filled with inert gas. One or more pumps (not shown) may be provided to assist in the fuel salt circulation, the primary coolant circulation or both. For example, an impeller may be provided in one or both of the heated fuel salt inlet channel at the top of the reactor core 804 or (as discussed in greater detail below) the cooled fuel outlet channels at the bottom of the reactor core 804. Likewise, an impeller may be provided in the coolant inlet channel 830 to assist in control of the primary coolant flow. FIG. 9 illustrates an alternative embodiment of the reactor of FIG. 8. In the embodiment shown, the reference numbers correspond to those of FIG. 8 for the same elements. FIG. 9 illustrates an alternative configuration for the tube sheets 931, 932 that reduces, even further, the exposure of the welded tube sheets to neutron flux from the fuel salt. In the embodiment shown, at the tubes of the tube set at least partially penetrate the upper and lower reflectors 908A and 908B at either end of the heat exchanger 910. In yet another embodiment, the tube sheet is eliminated in favor of the reflectors 908A, 908B which then performs the tube sheet's role of preventing fuel salt from shell side leaking into the coolant on the tube side. Note also that FIG. 9 illustrates a second lateral reflector 908D between the heat exchanger 910 and the coolant inlet channel 930. This can provide additional reflection or can simply be a moderator or other protection to reduce neutron flux outside of the core 904. U-Tube Configurations of Primary Heat Exchanger Another improvement in the reactor design is to switch the heat exchanger design to a shell-side fuel design and utilize a U-tube heat exchanger. In this design, the single tube sheet of the U-tube exchanger is located above the reactor core and outside of the containment vessel, and thus in a relatively reduced dose environment in comparison to the designs in FIGS. 2A-2C, 3, 4, and 6A-6C. FIG. 10 illustrates an embodiment of a reactor with a shell-side fuel, U-tube heat exchanger configuration in which the single tube sheet is located above the reactor core. In the embodiment, half of the reactor 1000 is illustrated as in FIGS. 8 and 9. The reactor core 1004 is surrounded by an upper reflector 1008A, a lower reflector 1008B, and an inner reflector 1008C that define the reactor core and separate it from the primary heat exchanger 1010. The spaces between the reflectors 1008A, 1008B, 1008C create channels allowing the circulation of fuel salt (illustrated by a dashed line 1006) from the reactor core 1004 over the inner reflector 1008C, through the shell side of the primary heat exchanger 1010, under the inner reflector 1008C, and back into the bottom of the reactor core 1004. Baffles 1012 are provided in the shell to force the fuel salt to follow a circuitous path around the tubes of the heat exchanger. Coolant flows through the U-shaped tubes of the heat exchanger 1010, so that the coolant both enters the tubes and exits the tubes from the top, through the single tube sheet 1032. The upper tube sheet 1032 is located in FIG. 10 some distance above the reactor core 1004 and containment vessel 1018, and thus its exposure to radiation is reduced relative to the other designs as discussed above. The flow of the coolant is also illustrated by a dashed line 1014. FIG. 10 illustrates a region 1034 within the shell of the heat exchanger that is above the level of salt in the reactor core 1004. Again, this region may either be solid, except for the penetrating tubes, or may be a headspace filled with inert gas. If solid, it may be filled with a reflector material through which the tube set penetrates. Again, one or more pumps, or at least their impellers, (not shown) may be provided to assist in fuel salt and/or coolant circulation. For example, an impeller may be provided in one or both of the heated fuel salt inlet channel at the top of the reactor core 1004 or the cooled fuel outlet channel at the bottom of the reactor core 1004. In yet another embodiment, welded components such as tube sheets 1032 may be shielded from neutrons with a sheet of neutron-absorbing material. The neutron-absorbing material may be placed adjacent to the tube sheet on the side facing the reactor core 1004. Such a tube sheet, neutron-absorbing material combination may be used in any embodiment discussed above. The neutron-absorbing material may be a coating, an additional layer, or an independent structural component adjacent to or spaced apart from the tube sheet. Yet another embodiment of a U-tube heat exchanger design rotates the heat exchanger 90 degrees so that the coolant enters and exits the heat exchanger laterally with reference to the containment vessel. FIG. 11 illustrates an embodiment of a reactor with a shell-side fuel, U-tube heat exchanger configuration in which the single tube sheet is within the reactor but laterally mounted in a location away from the reactor core. In the embodiment, half of the reactor 1100 is illustrated as in FIGS. 4A-6. The reactor core 1104 is surrounded by an upper reflector 1108A, a lower reflector 1108B and an inner reflector 1108C that separates the reactor core from the primary heat exchanger 1110. The spaces between the reflectors 1108A, 1108B, 1108C create channels allowing the circulation of fuel salt (illustrated by a dashed line 1106) from the reactor core 1104 over the inner reflector 1108C, through the shell side of the primary heat exchanger 1110, under the inner reflector 1108C, and back into the bottom of the reactor core 1104. Baffles 1112 are provided in the shell to force the fuel salt to follow a circuitous path around the tubes of the heat exchanger. Coolant flows through the U-shaped tubes of the heat exchanger 1110, so that the coolant both enters the tubes and exits the tubes from the top of the reactor 1000. In the embodiment shown, coolant enters the reactor in a channel next to the containment vessel 1118 and flows downward and then laterally through the lower portion of the tube sheet 1132 and into the heat exchanger 1110. The coolant then exits from the upper portion of the tube sheet 1132 and out of the top of the containment vessel 1118. The flow of the coolant is illustrated by a dashed line 1114. Because the tube sheet 1132 is farther from the reactor core, relative to the designs discussed above, exposure to radiation is reduced. Note that this design is also another embodiment of an actively cooled containment vessel as described above. In yet another embodiment, the U-tubes may be horizontally-oriented (not shown) as opposed to the vertically-oriented U-tubes illustrated in FIG. 11. This orientation may provide benefits in terms of heat transfer while still locating the tube sheets away from the high flux environment. In an embodiment, the tube sheet 1132 is further protected from neutron damage by providing a second inner neutron reflector (not shown) between the tube sheet and the fuel salt. In this embodiment, the tubes penetrate the second inner neutron reflector before coming into contact with the fuel salt. This serves to further distance the tube sheet from neutrons emitted by the fuel salt. In an alternative embodiment, the tube sheet 1132 is separated from the fuel salt by a neutron moderator made of some amount of material having a relatively large neutron absorption cross-section such as steel alloys or other materials that include Ag, In, Cd, Bo, Co, Hf, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu. For example, high boron steel, Ag—In—Cd alloys, boron carbide, Titanium diboride, Hafnium diboride, gadolinium nitrate, or any other material used as a control rod or neutron absorber, now known or later developed may be used. In an embodiment, the reflector or absorber may simply be a coating of the appropriate material on the salt contacting side of the tube sheet 1132. Radial Loop Reactor FIGS. 12A and 12B illustrate an alternative reactor design referred to as a radial loop reactor. FIG. 12A is a plan view of the reactor 1200 and FIG. 12B is a cross section along the line A-A indicated on FIG. 12A. In the embodiment of the radial loop reactor 1200 illustrated, a reactor core 1204 is defined by an upper reflector 1208A, a lower reflector 1208B and a lateral or inner reflector 1208C in the shape of a tube. The reflectors 1208 are within a core containment vessel 1218A that is penetrated by eight heated fuel salt outlet pipes 1209 located at the top of the containment vessel 1218A and eight cooled fuel salt return pipes 1211 that penetrate the containment vessel at a level of the bottom of the reactor core 1204. Each set of outlet pipe 1209, heat exchanger 1210 and return pipe 1211 may be referred to as a heat exchanger leg. Eight primary heat exchangers 1210 are shown in a diagonal configuration around the core containment vessel 1218A, although more or fewer primary heat exchangers 1210 may be used depending on the embodiment. It should also be noted that the heat exchanger legs may be vertical or may be more or less diagonal than shown. In the embodiment shown, heated fuel salt circulates from the reactor core 1204 through the outlet pipes 1209 and through the heat exchangers 1210. The heat exchangers cool the fuel salt which then returns to the bottom of the reactor core 1204 via the return pipes 1211. In the embodiment shown the reactor core 2204 is cylindrical in shape but this shape could be modified into a substantially frustoconically-shaped reactor core or substantially frustum-shaped reactor core as described above to improve natural circulation of the fuel salt during operation. The word “substantially” is used here to convey that the reactor core shape may not be a perfect frustum having perfectly flat surfaces for the bottom and top and perfectly flat or conical sides. For example, FIGS. 3 and 4 illustrate substantially frustum-shaped reactor cores even though flow directing bulges or other shapes are provided in the center of the top and bottom and on the sides of the reactor core. In an embodiment (not shown), one or more pumps (or at least the impeller components of such pumps) are provided in one or both of the return and outlet pipes 1211, 1209. In yet another embodiment (not shown), shutoff valves may also be provided in one or both of the return and outlet pipes 1211, 1209, as well as drain taps to allow any one of the eight heat exchanger legs to be independently shut off from the reactor core 1204 and drained of fuel salt for ease of maintenance. In an embodiment (not shown) one or more drain tanks may be provided below the level of the heat exchangers, the core containment vessel 1218A, or the heat exchanger legs for receiving drained fuel salt. In an alternative embodiment, each heat exchanger leg may include a pump in the inlet pipe that evacuates the heat exchanger of fuel salt when it is drained; returning the fuel salt to the reactor core 1204 instead of to a drain tank. One benefit of this layout is that the loop legs and the angles of the heat exchangers can be adjusted to provide additional flexibility for fuel pump location (pumps not shown) to be located at the bottom of the heat exchanger. Furthermore, pump shafts through/beside the heat exchangers or vessel penetrations from below are not required in this embodiment. As shown in FIG. 12D, a secondary containment vessel 1218B may be provided around the entire reactor core assembly, that is, around all the components in the fuel loop of the reactor 1200. In an embodiment, the secondary containment vessel has a volume sufficient to hold at least all of the fuel salt contained in the reactor. The size may be further increased to provide a safety margin and sized sufficiently large to hold both a volume of coolant and the entire volume of fuel salt in the reactor. The containment vessel may completely surround the radial loop reactor 1200 as shown, may partially surround the reactor, or may simply be a large vessel below the reactor 1200 of sufficient size. In the embodiment, primary coolant is circulated through the primary heat exchangers 1210 from above the secondary containment vessel 1218B. Radial loop reactors 1200 allow for the size of the primary heat exchangers 1210 to not be limited by the height of the reactor core 1204. Furthermore, as the heat exchangers are outside of the core containment vessel 1218A, they may be more easily serviced and controlled, as well as being farther away from the reactor core and therefore receiving a reduced dose of radiation. It will be clear that the systems and methods described herein are well adapted to attain the ends and advantages mentioned as well as those inherent therein. Those skilled in the art will recognize that the methods and systems within this specification may be implemented in many manners and as such is not to be limited by the foregoing exemplified embodiments and examples. In this regard, any number of the features of the different embodiments described herein may be combined into one single embodiment and alternate embodiments having fewer than or more than all of the features herein described are possible. While various embodiments have been described for purposes of this disclosure, various changes and modifications may be made which are well within the scope contemplated by the present disclosure. Numerous other changes may be made which will readily suggest themselves to those skilled in the art and which are encompassed in the spirit of the disclosure.
	abstract	The invention comprises a system for patient specific control of charged particles in a charged particle beam path using one or more trays inserted into the charged particle beam path, such as at the exit port of a gantry nozzle in close proximity to a tumor of a patient. Each tray holds an insert, such as a patient specific insert for controlling the energy, focus depth, and/or shape of the charged particle beam. Examples of inserts include a range shifter, a compensator, an aperture, a ridge filter, and a blank. Trays in a tray assembly are optionally retracted into an output nozzle of a charged particle cancer treatment system. Optionally and preferably, each tray communicates a held and positioned insert to a main controller of the charged particle cancer therapy system.
043103855	description	DESCRIPTION OF THE INVENTION Referring to the drawings, and particularly FIG. 1, there is illustrated a primary portion of a nuclear power plant generally represented by the numeral 10, and generally includes a reactor core containment vessel 11 (FIGS. 1-3), associated multiple steam generators 12 (only two shown), and pressurizing vessels 13. The typical nuclear reactor core containment vessel 11 of a nuclear power plant 10 is provided with a nuclear reactor core 14, a main containment portion 15 and a top 16. The heat producing atomic reaction is provided by atomic fuel elements 17 of core 14. Heat transferring coolant fluid is presented to containment vessel 11 by pumps 21 (FIGS. 1-3) through respective entry conduits or system 22 and downwardly through an inner annular plenary conduit 23 in vessel 11 into a lower chamber 24 in bottom portion 25 of the containment vessel 11. The heat absorbing and transferring fluid thereafter passes upwardly through the center of the containment vessel 11 past the reactor cores 14 to absorb the heat generated by the cores 14. The heated fluid is thereafter similarly forced by pumps 21 and thermal action, through exhaust conduits 26 to respective steam generators 12 by conduits 28. The heated fluid is transferred through heat transfer coils 31, of the respective steam generators 12, into chambers 32 thereof containing water 34 and returned to the pump by respective conduits 33. Water 34 of steam generators 12 is thus transformed into steam in the steam generators 12 in the upper portion of chamber 32 as a result of the heat of the heat-transfer fluid passing in coils 31. The steam is then fed from the steam generator chambers 32 to a steam turbine (not shown) by conduits 35 to operate a turbine and generator for the production of electricity. The steam is condensed through the operation of the turbine and returned to steam generator by condenser water return inlet conduits 36 to respective steam generators 12. Existing types of nuclear reactor power plants as generally referred to above (FIG. 1) are sometimes provided with a supplemental, fixed quantity, emergency coolant containers containing emergency core cooling liquids such as borated water. In the event of an emergency caused by a predetermined drop in pressure, or increase in temperature, in the primary coolant supply, emergency core coolant fluid could be expelled into respective conduits leading to the core containment vessel 11 through conduits 22. The purpose of this would be to try to reduce the temperature of fuel core 14 to prevent a melt down of individual fuel elements 14a. In this situation, the emergency core cooling fluid would pass from the emergency coolant container into the coolant fluid conduit 22 and into and through the containment vessel 11, to provide whatever cooling effect it might be able to provide to attempt to lower the temperature of the fuel elements 14a. Above and beyond the elements of a conventional nuclear power plant as previously generally described, this invention provides a eutectic solute holding vessel 41 to provide emergency melt down core catching capacity. Holding vessel 41 has a storage chamber 42 and a discharge chamber 43 interconnecting storge chamber 42 with conduit 22 of core containment vessel 11. Vessel 41 (FIGS. 2-6) is further provided with a valve means which includes a normally closed chamber pressure valve 45 between storage chamber 42 and discharge chamber 43, and a normally open heat responsive discharge valve 46, positioned in an exhaust outlet 47 of discharge chamber 43, and fluid conduit 22. Chamber valve 45 (FIGS. 2-7) is illustrated to include a valve seat opening 51 (FIG. 6) between storage chamber 42 and discharge chamber 43. A valve plate 52 is pivotally connected to a straight internal surface 53 within holding vessel 41. Plate 52 is complementary in shape to the cross sectional area of discharge chamber 43 (FIG. 6), and is adapted to be pivoted at 54 to upwardly engage a valve seat surface 55 whereby when valve plate 52 is pivoted clockwise about 54 (FIG. 7), plate 52 will ultimately seat against valve seat surface 55 (FIGS. 4-6) to seal exhaust chamber 43 from storage chamber 42. Plate is biased to be releasably retained in the closed position (FIGS. 4-6), and is similarly positioned by force of normal pressure from fluid system in conduit 22. Normally closed discharge valve 46 (FIG. 4) is provided with a heat expansion stem 61 connected to the far or bottom side of conduit 22 and a valve ball 62 on the upper end of stem 61 adapted to seat against tapered seat surface 63 of discharge chamber 43 to normally seal discharge chamber 43 from exhaust outlet 47 and fluid conduit 22. In operation, and in a situation of cold shutdown, (FIG. 4), discharge valve 46 will be normally closed, sealing the pressure of the fluid system in discharge chamber 43 to maintain chamber valve plate 52 in the up or seated and sealed position (FIGS. 4 and 5). In normal operation, stem 61 (FIGS. 5 and 7) will be elongated by virtue of the coefficient of expansion resulting from operating temperatures and will maintain discharge chamber 43 open into discharge outlet 47 and conduit 22 by unseating ball 61 from seat 62, thus maintaining discharge chamber 43 open to conduit 22. However, in the event of malfunction in a fluid system of conduits 22 causing a large reduction in pressure, stem 61 will be maintained elongated as above set forth to allow the discharge from chamber 43 into respective conduits 22. When the pressure in discharge chamber 43 is thus lowered, during operating conditions, the greater pressure in storage chamber 42 will urge the contents thereof downwardly against valve plate 52 causing plate 52 to be pivoted counterclockwise and downwardly (FIG. 5) to the open position (FIG. 7). In this instance, the contents of storage chamber 42 will be released, by the pressure thereof, from storage chamber 42 through the discharge chamber 43, discharge outlet 47, into the coolant system of conduit 22, and into the bottom chamber 24 of containment vessel 11 through inner conduit 23. Storage chamber 42 (FIGS. 4 and 5) is normally filled with fluxing eutectic solute of flux material granules 65 and coolant 66 and, as generally set forth above, maintained at a pressure significantly greater than outside air pressure and significantly lower than that of the fluid system in conduit 22, by a gas 67 such as nitrogen or argon. Eutectic solute material has a eutectic 65 in granular form adapted to mix with the plant coolant in exhaust chamber 43 and is propelled as a slurry through the conduits 22 and 23 to chamber 24 of primary containment vessel 11. Eutectic 65 is deposited as core catching mass or deposit 68 in the bottom of vessel 11 (FIG. 3) as the coolant vaporizes or otherwise rises through vessel 11 past core elements 14a. In the event of a core melt down, causing eutectic solute 66 to thus be passed from holding vessel 13 to containment vessel 11 to form core catching deposit 68, the molten fuel that starts to form from cores 14, as the melt down progresses, will gradually drop and eventually slump as a bolus into the mass of eutectic solute material 68 formed from granular eutectic 65 which is acting as a catcher for the core melt down material. Eutectic solute 65 as mass 68, will thereby dissolve the beginning droplets and eventual mass of any full scale or partial melt down, to cool the molten fuel thereof by the eutectic effect of solute mass 68, and by being dissipated over a large volume, creating a larger area for heat exchange, and thus also inhibiting nuclear heat production by absorption and dispersal. The eutectic solute material 65 can be any granular matter capable of being mixed with coolant 66 and dissolving with reactor fuel. For example, if a reactor is fueled with UO.sub.2 and cooled with liquid sodium, then anhydrous basalt granules could be used as solute material 67. Alternatively, if the reactor is fueled with metallic uranium and cooled with water, filings or shot of relatively carbon free iron could be used. It is desirable to provide a surfeit of eutectic solute material 67 and several routes of access to the primary containment vessel to allow for losses through ruptures in the system. The eutectic materials 67 may be maintained apart, shielded and even at points remote from core 14, thereby eliminating uncertainties involving prolonged exposure. The measures to prevent spurious triggering of current emergency core cooling systems can be applied to this system. A further refinement of this invention involves the use of a poison control substance with the eutectic solute 67. In this form, one could use boron compounds in conjunction with the borosilicate mixture used in uranium glass for a UO.sub.2 water cooled reactor. If, on the other hand, the reactor were fueled with metallic uranium, one could use filings of iron alloyed with cadmium. This embodies the added benefits of neutron absorption via fission poisoning. In these cases, the eutectic solute material 67 dissolves with control substance as well as fuel. In all embodiments, this system can effectively alleviate the damage to plant and environment by its immediate dissipative eutectic solute action, and if enough eutectic solute or poisoned eutectic solute 67 is present, the integrity of the primary containment vessel 11 may be significantly preserved. This invention is designed to be easily adaptable and retrofitable to existing reactors and many proposed designs. An appropriate glass, for the above referred to, can be a borosilicate glass. A specific example of an appropriate glass for this purpose is a glass of 80%, SiO.sub.2 ; 14%, B.sub.2 O.sub.3 ; and 4%, Na.sub.2 O; and 2%, Al.sub.2 O.sub.3. This formula, is fused into glass, and then ground or otherwise formed into pellets, particulate or granules of the proper size and a density greater than that of coolant 66 to allow transport through conduit systems 22 in suspension and under turbulence thereof, but dense enough to precipitate out of the coolant in the less turbulent area of the bottom of vessel 11, to form the core catcher or mass 68, it could be used as the eutectic solute to dissolve molten UO.sub.2. Additional coolant can be applied through conduits 49 under the control of valve 48 of respective holding vessels 41. This provides an additional option of pressurized coolant to force the discharge of the contents of storage chambers 42 through and past chamber valve 45 to discharge the contents of chamber 42 through discharge chamber 43 and exhaust conduit 47 into coolant system of conduits 22. Thus, an ejection system is provided upon command by the manipulation of valve 40 to provide the ability to discharge the vessels 41, on operator command, by raising the pressure in the storage chamber 42. Alternatively, conduit 35 can be linked with existing emergency core cooling systems such as borated water systems to initiate the discharge. Therefore, it should be noted that this invention provides a fuel core melt down catcher which is not otherwise provided by the state of the art and that is, moreover, readily deployable to existing systems in various altered forms or applications. It is to be understood that the invention is not to be limited to the specific constructions and arrangements shown and described, as it will be understood to those skilled in the art that certain changes may be made without departing from the principles of the invention.
	abstract	According to an X-ray diagnostic apparatus, an X-ray tube radiates X-rays. An X-ray collimator adjusts an irradiation region of the X-rays. An X-ray detector includes a first detector and a second detector having a smaller detection area than a detection area of the first detector. The X-ray detector is able to detect the X-rays radiated with the first detector and the second detector at the same time. Processing circuitry generates a synthesized image obtained by synthesizing a first X-ray image generated based on an output from the first detector that detected the X-rays radiated in the irradiation region adjusted, and a second X-ray image generated based on an output from the second detector that detected the X-rays radiated in the irradiation region adjusted, the synthesized image having an image size corresponding to an aspect ratio of the irradiation region. The processing circuitry causes a display to display the synthesized image.
	description	The present application claims the benefit of U.S. Provisional Patent Application 61/326,460, filed Apr. 21, 2010, the entirety of which is hereby incorporated by reference. The present invention relates generally to the field of energy reclamation, and specifically to systems and methods that reclaim energy from heat emanating from passively cooled spent nuclear fuel. In the operation of nuclear reactors, it is customary to remove fuel assemblies after their energy has been depleted down to a predetermined level. Upon removal, this spent nuclear fuel is still highly radioactive and produces considerable heat, requiring that great care be taken in its packaging, transporting, and storing. In order to protect the environment from radiation exposure spent nuclear fuel is first placed in a transportable canister. One such type of canister that has gained acceptance in the art is the multi-purpose canister (“MPC”). MPCs are hermetically sealed thermally conductive structures that effectuate the dry storage of spent nuclear fuel and are used to transfer and store said spent nuclear fuel. In a typical nuclear power plant, an open empty canister is first placed in an open transfer cask. The transfer cask and empty canister are then submerged in a pool of water. Spent nuclear fuel is loaded into the canister while the canister and transfer cask remain submerged in the pool of water. Once fully loaded with spent nuclear fuel, a lid is typically placed atop the canister while in the pool. The transfer cask and canister are then removed from the pool of water, the lid of the canister is welded thereon and a lid is installed on the transfer cask. The canister is then properly dewatered and back filled with inert gas. The canister is then hermetically sealed. The transfer cask (which is holding the loaded and hermetically sealed canister) is transported to a location where a storage cask is located. The canister is then transferred from the transfer cask to the storage cask for long term storage. During transfer from the transfer cask to the storage cask, it is imperative that the loaded canister is not exposed to the environment. Once the storage casks are loaded with the canisters, the canisters must be ventilated so that the heat emanating from the spent nuclear fuel (and thermally conducted through the canister) can be removed from the system. Spent nuclear fuel that is discharged from light water reactors is stored in the fuel pools so that its decay heat can be removed by tubular heat exchangers known as spent fuel pool coolers. The spent fuel pool coolers, either directly or through an intermediate heat exchanger, reject the waste heat to the plant's ultimate heat sink (such as a river, lake, or sea). The rate of decay heat generation from spent nuclear fuel drops rapidly with the passage of time. Most of the thermal energy produced by the used fuel thus winds up as waste heat rejected to the environment (most of it to the local natural source of water). Only after the heat emission rate has attenuated sufficiently can the fuel be transferred to dry storage. The nuclear plant operators have had little choice in the matter because the available dry storage technologies have strict limits on the decay heat that a loaded canister in dry storage can have. The present day limit on NRC licensed systems is roughly in the range of 20 to 45 kW per canister. The canister, upon transfer to dry storage, continues to reject heat to the environment (now, ambient air, in lieu of a body of water when kept in wet storage). While attempts have been made to create systems for reclaiming the energy resulting from the heat emanating from nuclear waste at storage sites, such systems are inadequate and/or unrealistic in their implementation. See, for example: (1) U.S. Pat. No. 3,911,684; U.S. Pat. No. 4,292,536; U.S. Pat. No. 5,771,265; and U.S. Patent Application Publication No. 2010/0199667. These systems are not particularly suited to work with canister-based dry storage and/or can not be realistically implemented on-site at nuclear power plants. Thus, a need exists for a system and method for reclaiming the energy potential from the heat emanating from nuclear waste that takes the aforementioned deficiencies into consideration. The present invention provides a system and method for reclaiming energy from the heat emanating from spent nuclear fuel contained within a canister-based dry storage system. The inventive system and method provides continuous passive cooling of the loaded canisters by utilizing the chimney-effect and reclaims the energy from the air that is heated by the canisters. The inventive system and method, in one embodiment, is particularly suited to store the canisters below-grade, thereby utilizing the natural radiation shielding properties of the sub-grade while still facilitating passive air cooling of the canisters. In another embodiment, the invention focuses on a special arrangement of the spent nuclear fuel within the canisters so that spent nuclear fuel that is hotter than that which is typically allowed to be withdrawn from the spent fuel pools can be used in a dry-storage environment, thereby increasing the amount energy that can be reclaimed. In one aspect, the invention can be an energy reclamation system comprising: at least one thermally conductive canister having a hermetically sealed cavity and a central axis, a basket disposed within the hermetically sealed cavity and comprising a grid of cells containing spent nuclear fuel emanating heat, wherein the grid of cells comprises a first region of cells and a second region of cells circumferentially surrounding the first region of cells, wherein the spent nuclear fuel contained within the first region of cells is hotter than the spent nuclear fuel contained within the second region of cells; a storage cavity, the canister disposed within the storage cavity; an air-intake passageway from an ambient environment to a bottom portion of the storage cavity; an air-outlet passageway from a top portion of the storage cavity to an ambient environment; and an energy reclamation unit disposed within the air-outlet passageway. In another aspect, the invention can be an energy reclamation system comprising: a plurality of storage cavities having substantially vertical axes and arranged in a spaced-apart side-by-side manner; at least one hermetically sealed canister containing spent nuclear fuel emanating heat positioned within each of the storage cavities; an air-intake passageway extending from an ambient environment to a bottom portion of each of the storage cavities; an air-outlet manifold fluidly coupling a top portion of each of the storage cavities to an air-outlet passageway, the air outlet manifold converging heated air exiting the top portions of the storage cavities and directing said converged heated air into the air-outlet passageway; and an energy reclamation unit located within the air-outlet passageway. In yet another aspect, the invention can be a method of utilizing heat emanating from spent nuclear fuel comprising: positioning at least one canister containing spent nuclear fuel emanating heat in each of a plurality of storage cavities having substantially vertical axes and arranged in a spaced-apart side-by-side manner; the heat emanating from the spent nuclear fuel heating air within the storage cavities, the heated air rising within the storage cavities and exiting the storage cavities at top portions thereof; converging the heated air exiting the top portions of the storage cavities with an air-outlet manifold that is fluidly coupled to the storage shells and directing said converged heated air into an air-outlet passageway; reclaiming energy of the heated air within the air-outlet passageway using an energy reclamation unit; and cool air being drawn into bottom portions of the storage cavities via an air-intake passageway. FIG. 1 shows decay heat attenuation curves for a typical PWR spent nuclear fuel assembly that has accumulated 45 and 55 GWD/MTU burn-up. As can be seen from FIG. 1, the heat generation rate drops first quite steeply and later less rapidly with the passage of time. Nuclear plant operators keep the fuel in the pool for many years, sometimes as long as 10 or 20 years, before moving it to dry storage. Thus, it can be seen that for purposes of reclaiming the energy potential from the heat emanating from the spent nuclear fuel, it is desirable to contain the spent nuclear fuel in a dry storage canister and position said loaded container within an energy reclamation system 1000, such as the one disclosed in FIGS. 4-6, as soon as possible. Of course, this desire must be balanced with the radiation being emitted from the loaded canisters and a safety margin for the heat level. The present invention changes decay heat produced by spent nuclear fuel from that of waste heat to reclaimable energy. This energy source, like solar power, is entirely green and is extracted by the energy reclamation system 1000 of the present invention, which is also an entirely passive cooling system. An ancillary outcome of this effort would be to remove fuel into dry storage after only a short sojourn in wet storage (perhaps a year or so). This early transfer of fuel from the pool to dry storage will be a welcome boost to the nuclear plant's safety in the eyes of the USNRC, which has publicly held dry storage to be a more robust storage configuration than its wet counterpart. Referring now to FIGS. 2-3 concurrently, a canister 100 according to one embodiment of the present invention is illustrated. In the exemplified embodiment, the canister 100 is a multi-purpose canister (“MPC”) that comprises a thermally conductive body 101 that is hermetically sealed to contain spent nuclear fuel in a dry storage environment. The thermally conductive body 101 generally comprises a canister shell 102, a bottom enclosure plate 103 and a top enclosure plate 104. The canister shell 102, the bottom enclosure plate 103 and the top enclosure plate 104 are connected at their interfaces 105 so that a hermetically sealed canister cavity is formed therein. Hermetic sealing of the interfaces 105 can be accomplished via seal welding and/or the use gaskets as is know in the art. The canister 100 extends from a bottom 107 to a top 108 along a longitudinal axis A-A. When positioned within the energy reclamation system 1000 for storage and passive cooling, the canister 100 is oriented so that the longitudinal axis A-A is substantially vertical. The canister 100 is particularly suited for use in an energy reclamation system 1000, such as the one disclosed in FIGS. 4-6, that reclaims the energy potential of heat emanating from spent nuclear fuel. The canister 100 is an extremely efficient heat-rejecting MPC that is capable of holding spent nuclear fuel with an aggregate heat load in excess of 60 kWs while maintaining the peak cladding temperature of the contained spent nuclear fuel below the U.S.N.R.C. limit of 400° C. (U.S.N.R.C. ISG-11 Rev 3). In order to ensure thermal conductivity, the canister shell 102, the bottom enclosure plate 103 and the top enclosure plate 104 are constructed of a thermally conductive material, such as carbon steel. If desired, the outer surface 106 of the canister a body 101 may be galvanized or coated (flame-sprayed or weld overlaid with a corrosion-resistant veneer) to protect against long-term corrosion. Moreover, if increased heat dissipation is desired, the outer surface 106 of the canister shell 102 may include features to increase its overall surface area. For example, the outer surface 106 may be given a non-smooth topography, such as dimpled, pitted, roughened, waved, and/or combinations thereof. Moreover, in certain embodiments, a plurality of fins could be coupled to the outer surface 106 in order to increase the overall heat dissipating area. Such fins could be longitudinally extending fins that are arranged in a spaced-apart manner about the circumference of the canister 100. The canister 100 can be manufactured in the manner of an MPC (see U.S.N.R.C. Docket No. 72-1014). The canister 100 further comprises a fuel basket 110 that is positioned within the hermetically sealed cavity formed by the canister body 101. In certain embodiments, the fuel basket 110 can be constructed of a metal matrix composite material, such as a discontinuously reinforced aluminum/boron carbide metal matrix composite material. One particularly suitable material is disclosed in U.S. Patent Application Publication No. 2010/0028193, filed as U.S. Ser. No. 12/312,089 on Jun. 14, 2007, the entirety of which is hereby incorporated by reference. Such material is commercially available as Metamic-HT™, which is a nanotechnology product containing aluminum and boron carbide that has an exceedingly high thermal conductivity and in the anodized state possesses an extremely high emissivity as well. The fuel basket 110 is formed by a gridwork of plates 111 arranged in a rectilinear configuration so as to form a grid of cells 112. Such an arrangement is licensed by the U.S.N.R.C. in Docket Mo. 71-9325. The cells 112 are elongated cells that extend substantially parallel to the longitudinal axis A-A. Thus, the cells 112 are substantially vertically oriented spaces having a generally rectangular horizontal cross-sectional configuration. Each cell 50 is designed to accommodate at least one spent nuclear fuel rod. Thus, the fuel basket 110 (and thus the cells 112) has a height that is greater than or equal to the height of the spent nuclear fuel rods for which the fuel basket 110 is designed to accommodate. One suitable construction of the fuel basket 110 is disclosed in U.S. Patent Application Publication 2008/0031396, filed as U.S. Ser. No. 11/772,610 on Jul. 2, 2007, the entirety of which is hereby incorporated by reference. Another suitable construction for the fuel basket 110 is disclosed in U.S. Pat. No. 5,898,747, issued on Apr. 27, 1999, the entirety of which is hereby incorporated by reference. The canister 100 further comprises a fuel basket spacer 115. In the exemplified embodiment, the fuel basket spacer 115 is a ring-like structure that circumferentially surrounds the fuel basket 110. However, in alternate embodiment, the fuel basket spacer 115 may be in the form of non-connected shims that fill the spaces between the fuel basket 110 and the inner surface 113 of the canister shell 102. The fuel basket spacer 115 is designed to provide conformal surface contact between the inner surface 113 of the canister shell 102 and the outermost peripheral panels 111 of the fuel basket 110 so as to provide an efficient path for the transmission of heat. In certain embodiments, the fuel basket spacer 115 can be constructed of an aluminum alloy (high thermal conductivity and thermal emissivity) in the manner of MPC-37 and MPC-89 fuel baskets in U.S.N.R.C. Docket Nos. 72-1032 and 71-9325. Other suitable fuel basket spacers 115 are disclosed in detail in U.S. Patent Application Publication 2008/0031397, filed as U.S. Ser. No. 11/772,620 on Jul. 2, 1010, the entirety of which is hereby incorporated by reference. In certain embodiments, the fuel basket spacer 115 is preferably constructed of a material that has a coefficient of thermal expansion that is greater than the coefficient of thermal expansion of the material of which the canister shell 102 is constructed, which in one embodiment is at least 20%. Because the fuel basket spacer 115 is constructed of a material having a greater coefficient of thermal expansion than that of the canister shell 102, the fuel basket spacer 115 expands at a greater rate and a larger amount than the canister shell 102 when subjected to heat emanating from spent nuclear fuel loaded within the cells 112. As a result, the outside surfaces of the fuel basket spacer 115 becomes pressed against the inner surface 113 of the canister shell 102, thereby achieving substantially continuous surface contact therebetween. Similarly, the inner surface of the fuel basket spacer 115 and the outer surface of the fuel basket 110 will also come into substantially continuous surface contact with each other so as to be under compression. Furthermore, the canister 100 is further configured to achieve a cyclical thermosiphon flow of gas within the hermetically sealed cavity of the canister body 102 when spent nuclear fuel emanating heat is contained within the cells 122. Such cyclical thermosiphon flow of the gas further enhances the transmission of heat to the outer surface 106 of the canister 100. Achieving cyclical thermosiphon flow within the canister can be achieved by providing downcomer passageways 116 within the fuel basket spacer 115 and providing cutouts in the top and bottom of the gridwork of plates 111 to form top and bottom distribution plenums. Suitable configurations to achieve such cyclical thermosiphon flow are disclosed in U.S. Patent U.S. Patent Application Publication 2008/0031396, filed as U.S. Ser. No. 11/772,610 on Jul. 2, 2007, and U.S. Pat. No. 5,898,747, issued on Apr. 27, 1999, the entireties of which are hereby incorporated by reference. In accordance with the present invention, spent nuclear fuel will be stored within the canister 100 in a special arrangement, which is shown in FIG. 2. In accordance with this arrangement, the grid of cells 112 is conceptually divided into three regions. The first region of the cells comprises the cells 1-1 to 1-9 and is centrally located along the longitudinal axis A-A. The hottest spent nuclear fuel is contained within the first region of cells 1-1 to 1-9. The second region of cells comprises cells 2-1 to 2-12. The second region of cells 2-1 to 2-12 circumferentially surrounds the first region of cells 1-1 to 1-9 and contains spent nuclear fuel that is cooler than the spent nuclear fuel contained within the first region of cells 1-1 to 1-9. The third region of cells 3-1 to 3-16 circumferentially surrounds the second region of cells 2-1 to 2-12 and contains spent nuclear fuel that is cooler than the spent nuclear fuel contained within the second region of cells 2-1 to 1-12. Thus, the hottest spent nuclear fuel is contained within the central region of the fuel basket 110 while the coldest spent nuclear fuel is contained within in the radially outermost region. The cold spent nuclear fuel in the outer second and third regions create a shielding buffer around the very hot spent nuclear fuel (that can be only one year old) contained within the first region. This allow the canister 100 to be loaded with very hot spent nuclear fuel, without excessive dose to personnel. While the fuel basket 110 is divided into three regions in the exemplified embodiment, it is possible for more less regions to be utilized as desired. While the canister 100 is particularly suited for use in the energy reclamation system 1000 described below, it is to be understood that the canister 100 can be used in other energy reclamation systems where it is desirable to maximize the amount of heat emanating from the spent nuclear fuel that can be reclaimed. Moreover, all canister types engineered for the dry storage of spent fuel can be used in conjunction with the energy reclamation system 1000 described below. Suitable other canisters include, without limitation, the MPC that is disclosed in U.S. Pat. No. 5,898,747 to Krishna Singh, issued Apr. 27, 1999, the entirety of which is hereby incorporated by reference. Referring now to FIGS. 3-6 concurrently, an energy reclamation system 1000 is exemplified according to an embodiment of the present invention. The energy reclamation system generally comprises a cavity enclosure array (“CEA”) 200 and an energy reclamation chamber 300. The energy reclamation chamber 300 comprises a housing 301 forming a energy reclamation cavity 302 in which an energy reclamation unit 303 is operably positioned. The energy reclamation chamber 300 is fluidly coupled to the CEA 200 so that heated air exiting the CEA 200 flows into the energy reclamation cavity 301, flows into operable contact with the energy reclamation unit 303, and flows out of the energy reclamation cavity 301, thereby escaping into the ambient atmosphere via outlet openings 304. The heated air flowing out of the CEA 200 is heated by the heat emanating from the spent nuclear fuel contained within the canisters 100 that are stored within the CEA 200 as discussed below. As further discussed below, the air flow through the CEA 200 is passive in nature in that its flow is driven by the chimney-effect. In the exemplified embodiment, the energy reclamation unit 303 is a heat exchanger that can extract thermal energy from the heated air flowing through the energy reclamation chamber 300 and transfer said extracted thermal energy into a second fluid, such as water. The heat exchanger may be a cross flow heat exchanger in which the heated air flowing through the energy reclamation chamber 300 flows in “cross flow” across a finned bundle carrying a tube-side fluid, such as pressurized water. Depending on the quantity and temperature of the heated air flowing through the energy reclamation chamber 300, the heated water may be used as feed water to the power plant, or to provide heated service water to the site. In one embodiment, the energy reclamation unit 303 is a heat exchanger that is part of a Rankine cycle power generation system. However, in alternate embodiments, if the decay heat is sufficiently high, then it is also possible to produce electric power using a wind mill or another energy conversion device. In such an embodiment, the energy reclamation unit 303 may be a wind turbine. While not limited in all embodiments, the CEA 200 is specifically designed to achieve the dry storage of multiple hermetically sealed canisters 100 containing spent nuclear fuel in a below grade environment, while at the same time harnessing the air heated by the spent nuclear fuel within the canisters 100. The CEA 200 converges the heated air streams exiting the storage cavities 201 and directs the converged heated air flow into the energy reclamation chamber 300 so that the energy within the heated air flow can be reclaimed by the energy reclamation unit 303. The CEA 200 is a vertical, ventilated dry spent fuel storage system that is fully compatible with 100 ton and 125 ton transfer casks for spent fuel canister transfer operations. The CEA 200 can be modified/designed to be compatible with any size or style transfer cask. The CEA 200 is designed to accept multiple spent fuel canisters for storage at an Independent Spent Fuel Storage Installation (“ISFSI”) or on-site at nuclear power plants. The CEA 200 is a storage system that facilitates the passive cooling of the canisters 100 disposed therein through natural convention/ventilation. The CEA 200 is free of forced cooling equipment, such as blowers and closed-loop cooling systems. Instead, the CEA 200 utilizes the natural phenomena of rising warmed air, i.e., the chimney effect, to effectuate the necessary circulation of air about the canisters 100. In essence, the CEA 200 comprises a plurality of modified ventilated vertical modules that can achieve the necessary ventilation/cooling of multiple canisters 100 containing spent nuclear in a below grade environment, while at the same time converging and directing the heated air exiting each of the storage cavities 201 to energy reclamation chamber 300. The CEA 200 generally comprises a vertically oriented air-intake shell 210A, a plurality of vertically oriented storage shells 210B, an air-intake manifold 220 and an air-outlet manifold 230. The storage shells 210B and the air-intake shell 210A are secured to a baseplate 240 (FIG. 6) that is in turn secured atop a reinforced concrete pad 241. The baseplate(s) 240 can be keyed to prevent lateral sliding during an earthquake. The connection between the bottom edges 208 of the storage shells 210B and the air-intake shell 210A and the baseplate 240 is a hermetic seal so as t0 prevent the ingress of below grade fluids. In the exemplified embodiment, only a single air-intake shell 210A and a single energy reclamation chamber 300 (which acts as an outlet plenum) is utilized. However, in alternate embodiments, more than one air-intake shell 210A and/or energy reclamation chamber 300 can be incorporated into the CEA 200 as desired. The storage shells 210B surround the air-intake shell 210A. In the exemplified embodiment, the air-intake shell 210A is structurally similar to the storage shells 210B, with the exception that the air-intake shell 210A is not fluidly coupled to the air-outlet manifold 230 (discussed in greater detail below). As will be discussed below, the air-intake shell 210A remains empty (i.e., free of a heat load and unobstructed) so that it can act as an inlet passageway for cool air to enter the air-inlet manifold 220. Each of the storage shells 10B form a storage cavity 201 which receives at least one hermetically sealed canister 100 containing spent nuclear fuel. It should be noted that in alternate embodiments, the air-intake shell 210A can be designed to be structurally different than the storage shells 210B so long as the air-intake cavity 202 of the air-intake shell 10A allows cool air to enter the air-inlet manifold 220 so that said cool air can ventilate the storage shells 210B. Stated simply, the air-intake cavity 202 of the air-intake shell 10A acts as a downcomer passageway for the inlet of cooling air into the air-inlet manifold 220. For example, the air-intake shell 210A can have a cross-sectional shape, cross-sectional size, material of construction and/or height that can be different than that of the storage shells 210B. In the exemplified embodiment, both the air-intake shell 210A and the storage shells 210B are cylindrical in shape having a circular horizontal cross-section. However, in other embodiments the shells 210A, 210B can take on other shapes, such as rectangular, etc. The shells 210A, 210B have an open top end and a closed bottom end. The shells 210A, 210B are arranged in a side-by-side orientation forming an array. The air-intake shell 210A is located in a non-perimeter location of the array. The invention, however, is not so limited. The location of the air-intake shell 210A in the array can be varied as desired The shells 210A, 210B are preferably in a spaced-apart in a side-by-side relationship with respect to one another. The horizontal distance between the vertical center axis of the shells 210A, 210B is in the range of about 10 to 20 feet, and more preferably about 15 feet. However, the exact distance between shells 210A, 2101B will be determined on case by case basis and is not limiting of the present invention. The shells 210A, 210B are preferably constructed of a thick metal, such as steel, including low carbon steel. However, other materials can be used, including without limitation metals, alloys and plastics. Other examples include stainless steel, aluminum, aluminum-alloys, lead, and the like. The thickness of the shells 210A, 210B is preferably in the range of 0.5 to 4 inches, and most preferably about 1 inch. However, the exact thickness of the shells 210A, 210B will be determined on a case-by-case basis, considering such factors as the material of construction, the heat load of the spent fuel being stored, and the radiation level of the spent fuel being stored. The CEA 200 further comprises a removable lid 203 positioned atop each of the storage shells 210B. The lids 203 are positioned atop the storage shells 210B, thereby enclosing the open top ends of the storage cavities 201 formed by the storage shells 210B. The lids 203 provide the necessary radiation shielding so as to prevent radiation from escaping upward from the storage cavities 201 formed by the storage shells 10B when the canisters 100 containing spent nuclear fuel are positioned therein. The lids 203 are secured to the storage shells 210B by bolts or other detachable connectors. The lids 203 are capable of being removed from the storage shells 210B without compromising the integrity of and/or otherwise damaging either the lids 203 or the storage shells 210B. In other words, each lid 203 forms a non-unitary structure with respect to its corresponding storage shell 210B. In certain embodiments, however, the lids 203 may be secured to the storage shells 210B via welding or other semi-permanent connection techniques that are implemented once the storage shells 210B are loaded with one or more canisters 100 loaded with spent nuclear fuel. The removable lids 203 further comprises one or more layers of insulation 204 on a bottom surface thereof to prevent the heated air that rises into the top portions 201B of the storage cavities 201 from being cooled prior to (or during) flow through the air-outlet manifold 230. The lids 203 are detachably secured to top edges 205 of the storage shells 210B so that a hermetic seal is formed therebetween that prevents in-leakage of water. This can be accomplished through the use of gaskets or a seal weld. The lids 203 are solid and include no penetrations or passages. Thus, when the lids 203 are secured t the storage shells 210B, the top ends of the storage cavities 201 are hermetically sealed (with the exception of the air-outlet passageways formed by the air-outlet manifold 230 of course). Referring still to FIGS. 4-6 concurrently, the CEA 200 further comprises an air-inlet manifold 220. The air-inlet manifold 220, in the exemplified embodiment, is a network of pipes 221 that fluidly couple the storage cavities 201 of the storage shells 210B together and to the air-intake cavity 202 of the air-intake shell 210A. More specifically, the network of pipes 221 that form the air-inlet manifold 220 form hermetically sealed horizontal passageways 222 between the bottom portions 201A of the storage cavities 201 and the bottom portion 202A of the air-intake cavity 202. The air-intake shell 210A (and thus the air-intake cavity 202) extends from above the grade 450 of the ground 400 to protect against intrusion of debris, floodwater, etc., and to provide for an improved air suction action. One air-intake cavity 202 may serve an array of storage cavities 201 through the air-inlet manifold 220. The air-intake cavity 202 of the air-intake shell 210A, in combination with the various hermetically sealed passageways 222 of the air-intake manifold 220 form an air-intake passageway extending from the ambient atmosphere to the bottom portion 201A of each of the storage cavities 201. As result, cool air can enter the inlet openings 215 of the air-intake shell 210A, flow downward into the air-intake cavity 202, flow through the hermetically sealed passageways 222, and into the bottom portions 201A of the storage cavities via the inlet openings 206 formed in the sidewalls of the storage shells 210B. Once inside the storage cavities, this cool air will be drawn upward through the storage cavities 201 and into contact with the canisters 100 as discussed below. Conceptually, the air-intake manifold 220 acts as a lower plenum that distributes incoming cool air to from the air-intake cavity 202 of the air-intake shell 201A to the storage cavities 201 of the storage shells 210B. In alternate embodiments, however, the air-intake passageway that extends from the ambient atmosphere to the bottom portions 201A of the storage cavities 201 can be separate and distinct passageways for each storage cavity 201 and do not have to run through a manifold and/or common air-intake cavity. The network of pipes 221 of the air-inlet manifold 220 that join storage shells 210B are equipped with an expansion joint 225 that acts as a “flexible shell element” to structurally decouple each of the storage shells 210B from one another and the air-intake shell 210A. The CEA 200 further comprises an air-outlet manifold 230 that fluidly couples the top portions 201B of the storage cavities 201 of the storage shells 210B to one another and to the energy reclamation chamber 300. The air-outlet manifold 230 is not fluidly coupled to the air-intake cavity 202 of the air intake shell 210A. The air-outlet manifold 230, in the exemplified embodiment, is a network of pipes 231 that fluidly couple the storage cavities 201 of the storage shells 210B together and to the energy reclamation chamber 300. More specifically, the network of pipes 231 that form the air-outlet manifold 220 form hermetically sealed horizontal passageways 232 between the top portions 201B of the storage cavities 201 and the energy reclamation cavity 302 of the energy reclamation chamber 300. The energy reclamation cavity 302, in combination with the various hermetically sealed passageways 232 of the air-outlet manifold 230, form an air-outlet passageway extending from the top portion 201B of each of the storage cavities 201 to the ambient atmosphere. As a result, heated air within the top portions 201B of the storage cavities 201 can exit the storage cavities 201 through the outlet openings 215 of the storage shells 210B, flow through the hermetically sealed passageways 232, and into the energy reclamation chamber 300 where the energy from the heated air is reclaimed by the energy reclamation unit 303. The outlet openings 207 are located within the sidewalls of the storage shells 210B. One energy reclamation chamber 300 may serve an array of storage cavities 201 through the air-outlet manifold 220. The top edges 205 of the storage shells 210A extend equal to or above the grade 450 of the ground 400 so that each of the storage cavities 201 can be independently accessed from above-grade. While one embodiment of a plumbing/layout for the networks of pipes 221, 231 of the air-intake and air-outlet manifolds 220 is illustrated, the invention is not limited to any specific layout. Those skilled in the art will understand that an infinite number of design layouts can exist for the piping networks. Furthermore, depending on the ventilation and air flow needs of any given energy reclamation system 1000, the piping network may or may not comprise headers and/or expansion joints. The exact layout and component needs of any piping network will be determined on case-by-case design basis. The internal surfaces of the air-intake and air-outlet manifolds 220, 230 and the shells 210A, 210B are preferably smooth so as to minimize pressure loss. Similarly, ensuring that all angled portions of the piping network are of a curved configuration will further minimize pressure loss. The size of the pipes 221, 231 can be of any size. The exact size of the ducts will be determined on case-by-case basis considering such factors as the necessary rate of air flow needed to effectively cool the canisters. All components (pipes, expansion joints, etc.) of the air-intake and air-outlet manifolds 220, 230 are seal joined to one another at all connection points. Moreover, the air-intake manifold 220 is seal joined to all of the shells 210A, 210B while the air-outlet manifold 230 is seal joined to all of the storage shells 210B and the energy reclamation chamber 300, thereby forming an integral/unitary structure that is hermetically sealed to the ingress of water and other fluids. In the case of weldable metals, this seal joining may comprise welding and/or the use of gaskets. Thus, the only way water or other fluids can enter any of the cavities 201, 202 of the shells 210A, 210B or the manifolds 220, 230 is through the inlet openings 215 of the air-intake shell 210A and the outlet openings 304 of the energy reclamation chamber 300. An appropriate preservative, such as a coal tar epoxy or the like, is applied to the exposed surfaces of shells 210A, 210B and the manifolds 220, 230 to ensure sealing, to decrease decay of the materials, and to protect against fire. A suitable coal tar epoxy is produced by Carboline Company out of St. Louis, Mo. under the tradename Bitumastic 300M. A layer of insulating material 260 circumferentially surrounds each of the storage cavities 201. The layer of insulating material layer 260 may be located within or outside of the storage shells 110B. Suitable forms of insulation include, without limitation, blankets of alumina-silica fire clay (Kaowool Blanket), oxides of alumina and silica (Kaowool S Blanket), alumina-silica-zirconia fiber (Cerablanket), and alumina-silica-chromia (Cerachrome Blanket). The insulation 260 prevents excessive transmission of heat from spent nuclear fuel of the canisters 100 within the storage shells 210B to the surrounding radiation absorbing material 400, which can be the ground, a concrete mass or other engineered fill. Moreover, the network of pipes 231 of the air-outlet manifold 230 can also be insulated in a similar manner to further minimize heat loss. Insulating the storage shells 210B and the air-outlet manifold 230 serves to minimize the heat-up of the incoming cooling air before it enters the storage cavities 201 of the storage shells 210B and preserves the thermal energy of the heated air as is travels through the air-outlet manifold 230 to the energy reclamation chamber 300. As mentioned above, each of the storage shells 210B and the air-intake shell 210A are arranged in a side-by-side relation so that the bottoms edges 208 of the shells 210A, 210B are located in the same plane. Similarly, the top edges 205 of all of the storage shells 210A, 210B are also located in the same plane. In one embodiment, the entirety of the both the air-intake and air-outlet manifolds 220, 230 is located in or between these planes respectively. Each of the air-intake shell 210A and the energy reclamation chamber 300 comprises a cap that prohibits rain water and other debris from entering into the inlet and outlet openings 115, 304 while affording cool air to enter and heated air to escape the system 100 respectively. The storage shells 210B form vertically oriented cylindrical storage cavities 201. While the storage cavities 201 are cylindrical in shape having a circular horizontal cross-section, the storage cavities 210B are not limited to any specific shape, but can be designed to receive and store almost any shape of canister 100 without departing from the spirit of the invention. The horizontal cross-sectional size and shape of the storage cavities 201 of the storage shells 210B are designed to generally correspond to the horizontal cross-sectional size and shape of the spent fuel canisters 100 that are to be stored therein. The horizontal cross-section of the storage cavities 201 of the storage shells 210B accommodate no more than one canister 100 of spent nuclear fuel. Further, the horizontal cross-sections of the storage cavities 201 of the storage shells 210B are sized and shaped so that when the canisters 100 are positioned therein for storage, an annular gap/clearance 250 exists between the outer side walls of the canisters 100 and the inner side walls of cavities 201. Designing the storage cavities 201 of the storage shells 210B so that a small gap 250 is formed between the side walls of the stored canisters 100 and the side walls of the storage cavities 201 limit the degree the canisters 100 can move within the storage cavities 201 during a catastrophic event, thereby minimizing damage to the canisters 100 and the cavity walls and prohibiting the canisters 100 from tipping over within the storage cavities 201. These small gaps 250 also facilitates flow of the heated air during spent nuclear fuel cooling. The exact size of the annular gaps 250 can be controlled/designed to achieve the desired fluid flow dynamics and heat transfer capabilities for any given situation. The size of the air flow gaps 250 can also be selected with the aid of a suitable Computational Fluid Dynamics model to maximize the temperature of the exiting heated air. In one embodiment, the annular gaps 250 have a width of about 1 to 3 inches. Depending on the site, the storage cavities 201 may be stacked with 2 or 3 canisters 100 to maximize the heat load in each storage cavity 201. Stacked canisters 100 can be supported by a set of wedge-type supports 270 that also act as seismic restraints against excessive lateral rattling of the canisters 100 under an earthquake event. The wedge type restraints 270 are designed to minimize hydraulic resistance to the axial flow of ventilation air. The top region of the uppermost canister 100 in the stack is also protected from excessive rattling by the wedge-type restraints 270. When loaded within the storage cavities 201, the canisters 100 are positioned so that the top 108 of the uppermost canister 100 within the stack is below the bottoms of the outlet openings 207 that allow the heated air within the top portions 201B of the storage cavities 201 to enter into the air-outlet manifold 230. Thought of another way, the outlet openings 207 are at a greater elevation than the tops 108 of the uppermost canisters 100 in the stack. Similarly, the lowermost canister 100 in the stacks sit atop a set of alignment lugs that are located such that the bottoms 107 of the lowermost canister 100 in the stacks are above the inlet openings 206 thru which ventilation air enters the bottom portions 201A of the storage cavities 201. Thought of another way, the inlet openings 206 are located at an elevation that is lower than the bottoms 107 of the lowermost canisters 100 in the stacks. When only a single canister 100 is positioned within the storage cavities 201, the canister 100 can be considered both the uppermost and lower most canister for these purposes. In the illustrated embodiment of the energy reclamation system 1000, a radiation absorbing material 400 surrounds the shells 210A, 210B and the manifolds 220, 230. The radiation absorbing material 400 can be a concrete monolith, soil, or a suitable engineered fill. Furthermore, a top surface pad made of reinforced concrete or a similar structurally competent slab, surrounds the top portions of the storage shells 210B and the air-outlet manifold 230 and serves as the haul path and staging surface for the canister installation or extraction. The radiation absorbing material 400 provides the necessary radiation shielding for the spent nuclear fuel canisters 100 stored in the storage shells 210B. As mentioned above, the CEA 200 is particularly suited to effectuate the storage of spent nuclear fuel canisters 100 in a below grade environment. The CEA 200, including the radiation absorbing material 400, is positioned so that at least the major portions of the heights of the storage shells 210B are below the grade 450. Thus, the storage shells 210B are fully or partially surrounded by the subgrade. Both the air-intake and air-outlet manifolds are also located below the grade 450. By positioning the CEA 200 below the grade 450, the system 1000 is unobtrusive in appearance and there is no danger of tipping over. The low profile of the underground manifold storage system 1000 does not present a target for missile or other attacks. A small portion that includes the top edges 105 of the storage shells 210B protrude above the grade 450 so that the storage cavities 201 can be independently and easily accessed for canister transfer and maintenance. In the exemplified embodiment, the storage shells 210B are sufficiently below grade level so that when the canisters 100 of spent fuel are positioned in the storage cavities 201, the entire height of the canisters 100 are below the grade 450. This takes full advantage of the shielding effect of the surrounding soil. Thus, the soil provides a degree of radiation shielding for spent fuel stored that can not be achieved in aboveground facilities. An embodiment of a method of reclaiming the energy from heat emanating from the heat emanating from a canister 100 loaded with spent nuclear fuel utilizing the energy reclamation system 1000 will be described. First, the canister 100 is loaded with spent nuclear fuel in a spent fuel pool utilizing the regional loading approach described in FIGS. 1-3 above. Upon being removed from a spent fuel pool and treated for dry storage, the spent fuel canister 100 is hermetically sealed and positioned in a transfer cask. The transfer cask is then carried by a cask crawler to an empty storage shell 210B. Any suitable means of transporting the transfer cask to a position above the storage shell 210B can be used. For example, any suitable type of load-handling device, such as without limitation, a gantry crane, overhead crane, or other crane device can be used. In preparing the desired storage shell 210B to receive the canister 100, the lid 203 is removed so that the storage cavity 201 of the storage shell 210B is open and accessible from above. The cask crawler positions the transfer cask atop the storage shell 210B. After the transfer cask is properly secured to the top of the storage shell 210B, a bottom plate of the transfer cask is removed. If necessary, a suitable mating device can be used to secure the connection of the transfer cask to storage shell 210B and to remove the bottom plate of the transfer cask to an unobtrusive position. Such mating devices are known in the art and are often used in canister transfer procedures. The canister 100 is then lowered by the cask crawler from the transfer cask into the storage cavity 201 of the storage shell 210B until the bottom 207 of the canister 100 either rests on the support lugs or atop another previously loaded canister 100. At this time, the entire height of the canister 100 is below the grade level 450. Once the canister 100 is positioned and resting in the storage cavity 201, the lid 203 is positioned atop the storage shell 210B, substantially enclosing the storage cavity 201. The lid 203 is then secured in place via bolts or other means. When the canister 100 is so positioned within the cavity 201 of the storage shell 10B, the top and bottom portions 201B, 201A of the storage cavity 201 remain a fee volume. Moreover, the small annular gap 250 also exists between the side walls of the canister 100 and the wall of the storage shell 210B. The annular gap 250 extends between the top and bottom portion 201B, 201A of the storage cavity 201, thereby providing a passageway between the two. As a result of the chimney effect caused by the heat emanating from the spent nuclear fuel within the canister 100, cool air from the ambient is siphoned into the air-intake cavity 202 of the air-intake shell 210A via the inlet openings 215. This cool air is then siphoned through the network of pipes 221 of the air-intake manifold 220 and distributed into the bottom portions 201A of the storage cavities 201. This cool air is then warmed by the heat emanating from the spent nuclear fuel within the canisters 100, rises within the storage cavities 201 via the annular gap 250 around the canister 80, and into the top portions 201B of the storage cavities 201 above the canisters 100. This heated air exits the storage cavities 201 via the outlet openings 207 and enters into the network of pipes 231 of the air-outlet manifold 230. The heated air exiting all of the storage cavities 201 converges within the air-outlet manifold 230 where it is directed to and aggregated within the energy reclamation cavity 302, which acts as a vertically oriented outlet plenum. As passing through the energy reclamation cavity 302, the energy of the heated air is reclaimed using the energy reclamation unit 303 as discussed above. While the invention has been described and illustrated in sufficient detail that those skilled in this art can readily make and use it, various alternatives, modifications, and improvements should become readily apparent without departing from the spirit and scope of the invention.
	description	1. Field of the Invention This invention relates generally to method and system for calculating rod average criteria in a nuclear reactor. 2. Description of Related Art Operating nuclear plants have to conform to regulatory board guidelines for evaluating radiological consequences of design basis accidents. These guidelines provide guidance to licensees of operating power reactors on acceptable applications of Alternative Source Terms (AST); the scope, nature, and documentation of associated analyses and evaluations; consideration of impacts on analyzed risk; and content of submittals. The guidelines establish an acceptable AST and identify the significant attributes of other ASTs that may be found acceptable by the U.S. Nuclear Regulatory Commission (NRC). The guidelines also identify acceptable radiological analysis assumptions for use in conjunction with the accepted AST. The NRC mandates these guidelines in 10 CFR Part 50 documentation, particularly, 10 CFR 50.67 which describes the AST methodology characterized by radionuclide composition and magnitude, chemical and physical form of the nuclides, and the timing of release of these radionuclides. As part of the AST methodology, the inventory of fission products in the reactor core and availability of release to the containment may be determined to be acceptable for use with currently approved fuel. These values are evaluated to determine whether they are consistent with the safety margins, including margins to account for analysis uncertainties. The safety margins are products of specific values and limits contained in the technical specifications (which cannot be changed without NRC approval) and other values, such as assumed accident or transient initial conditions or assumed safety system response times. As an example, fractions of fission product inventory for fuel with a peak exposure up to, for example, 62,000 MWD/MTU (Mega Watt-Days per metric ton of Uranium) may be evaluated, if the maximum linear heat generation rate does not exceed 6.3-kW/ft (kilo-Watt per feet) peak rod average power for exposures exceeding 54,000 MWD/MTU. In other words, the AST methodology basis may simplify the acceptance criterion, (i.e., if the peak rod average exposure exceeds 54,000 MWD/MTU, then the rod's average linear heat generation rate cannot exceed 6.3 kW/ft). Further, fission gas release calculations should be performed using approved methodologies, and the U.S. NRC may consider the methodology on a case-by-case basis. However, current AST methodologies do not have a manner in showing compliance of criterion during the design, optimization, licensing, and/or monitoring phases because current methodologies fail to directly calculate the constraint. In other words, to obtain the criterion of the rods, one may need to manipulate data that is external to the design, optimization, licensing, and/or monitoring phases, which may be a time-consuming and laborious process. Further, conservative assumptions may be employed to determine the criteria, however, this procedure may provide inaccurate criteria, which may adversely impact plant operations. The present invention may provide a method and system to define a systematic manner of calculating the constraints in each fuel assembly. Further, exemplary embodiments of the present invention may employ a method to design, optimization, licensing, and/or monitoring applications in a general and flexible manner based on the averaging of weighted (axially) nodal quantities. Further, exemplary embodiments of the present invention may not be dependent on any particular set of methodologies. Exemplary embodiments of the present invention may provide a method of calculating and using a constraint having at least utilized pin nodal exposures and pin nodal powers to obtain the constraint, calculating rod average exposures and rod average powers (kW/ft) in each fuel assembly, developing core maps from the calculated rod average exposures and powers (kW/ft), and outputting the developed maps. Other exemplary embodiments may provide the calculation of the rod average exposures and powers (kW/ft) by calculating pin nodal exposures in each axial fuel node. Other exemplary embodiments may provide the calculation of the rod average exposures and powers (kW/ft) by calculating pin nodal powers in each axial fuel node. Other exemplary embodiments may further provide the weight factor of the pin nodal exposures. Other exemplary embodiments may provide the weight factor as one of a total nodal weight and a pin nodal weight. Other exemplary embodiments may provide the core maps as two-dimensional (2D). In yet other exemplary embodiments, determining the rod average exposure may develop the 2D core maps. In yet other exemplary embodiments, determining the rod average power (kW/ft) may develop the 2D core maps. In yet other exemplary embodiments, determining a peak rod average exposure may develop the 2D core maps. In yet other exemplary embodiments, determining a peak rod average power (kW/ft) may develop the 2D core maps. In yet other exemplary embodiments, the 2D core maps may be developed by a ratio of a peak rod average power (kW/ft) to a limit for AST considerations. Other exemplary embodiments may provide the calculation of the rod average exposures and the rod average powers (kW/ft) in a selected fuel assembly. Other exemplary embodiments may further provide editing the outputted generation maps. Exemplary embodiments of the present invention may provide a method of calculating and using a constraint for fuel rods in a nuclear reactor having at least utilized pin nodal exposures and pin nodal powers to obtain the constraint, calculating rod average exposures and rod average powers (kW/ft) in each fuel assembly, developing two dimensional (2D) core maps from the calculated rod average exposures and powers (kW/ft), outputting the developed 2D maps, and editing the outputted generation 2D maps. These and other features and advantages of this invention are described in, or are apparent from, the following detailed description of various exemplary embodiments of the method and systems according to the invention. The following description is directed toward a presently preferred embodiment of the present invention, which may be operative as an end-user application running. The present invention, however, is not limited to any particular computer system or any particular environment. Instead, those skilled in the art may appreciate that the system and method of the present invention may be advantageously applied to environments requiring management and/or optimization of any multiple control-variable critical industrial/scientific process or system, including chemical and mechanical process simulation systems, pressurized water reactor simulation systems, boiling water reactor simulation systems, and the like. Moreover, the invention may be embodied on a variety of different computer software platforms, including, for example, but not limited to UNIX, LINUX, Macintosh, Windows, Next Step, Open VMS, and the like, used for design, optimization, licensing, and/or monitoring applications. Therefore, the description of the exemplary embodiments, which follows, is for purposes of illustration and not a limitation. Exemplary embodiments of the present invention may provide a method of calculating and using constraints within the context of an operating nuclear reactor cycle design, licensing, and/or monitoring phase. The U.S. Nuclear Regulatory Commission (NRC) criterion for off-site dose calculations and radiological consequences may be the basis for the constraint. Current methods do not have the means to show compliance of the criterion because the methods do not directly calculate the constraint. It should be appreciated that the methods may include computer codes (i.e., core simulators) used for design, optimization, licensing, and/or core monitoring systems used to monitor a reactor operation. As an exemplary embodiment, the constraint may be on the peak rod average exposure, and its linear heat generation rate (usually indicated by kW/ft). Further, the constraint may also be on peak rod average liner heat generation rate, which may not necessarily be in the rod with peak average exposure. In an exemplary embodiment, a fuel assembly may have as many as 10×10 rods in a boiling water nuclear reactor (BWR). In it, the averaging may be over axial nodes (e.g., zones), as identified by the core simulator model. A typical BWR fuel assembly, for example may have as many as 25 axial nodes. Accordingly, the present invention may define a systematic method of calculating in each fuel assembly, the rod with peak average exposure and liner heat generation rate (kW/ft), and the rod with peak kW/ft and its exposure. In addition, the present invention may employ methods to design, optimization, licensing, and/or monitoring applications. Thus, the present invention may provide the ability to address the constraint in a general and flexible manner based on the averaging of weighted (axially) nodal quantities, and not dependent on any particular set of methodologies. It should be appreciated throughout the description that “pin nodal” may refer to a part of the rod in an axial node. It should further be appreciated that the “linear heat generation rate” (kW/ft) may also refer to “power”. FIG. 1 is a flowchart of a method for calculating rod peak criteria in accordance with an exemplary embodiment of the invention. As shown in FIG. 1, the operation begins at S100 and proceeds to S200 in which the operation may utilize pre-defined process to perform pin-exposure and pin-power reconstruction. A pre-defined process may be a pre-existing, well-defined process (e.g., pin-exposure reconstruction and pin-power reconstruction) that is used to determine the criterion, such as the rod average exposure and rod average power (kW/ft) in each fuel assembly. It should be appreciated that the pre-defined process may be specific to the set of methods used. Next, in S300, the operation calculates the rod average exposure and power (kW/ft). Specifically, the calculation may determine: a) peak rod average exposure, b) rod average power (kW/ft) for that rod, c) peak rod average power (kW/ft), and d) rod average exposure for that rod. The rod averages may be performed by an axially averaging for each rod in the assembly. The calculation may be performed utilizing the constraints and implementing into an algorithm described herein. With the calculated rod average exposure and power (kW/ft), the operation may proceed to S400 so as to input the rod average exposure limit and power (kW/ft) limit. The limits may be formed into an AST. The AST methodology basis may formulate the criterion based on limits for both: the peak rod average exposure and its power (kW/ft). For example, if the peak rod average exposure goes over 54,000 MWD/MTU, then this rod's average linear heat generation rate cannot exceed 6.3-kW/ft. Then in S500, the output generation for all the fuel assemblies may be developed to obtain the two-dimensional (2D) core maps. The 2D maps may be used to directly and/or indirectly calculate the constraints. The 2D maps may be generated from: a) the peak rod average exposure, b) the rod average power (kW/ft) for that rod, c) the peak rod average power (kW/ft), and d) the rod average exposure for that rod. It should be appreciated that the operation may also have the option to generate maps of rod average exposure and rod average power (kW/ft) in selected assemblies. In S600, the operation may edit and map the output generation. The maps may be available as output data for further processing. For example, during the design phase one may be interested in further processing of the 2D maps in selected assemblies to determine the magnitude and extent of the problem, (i.e., if it is a “local” problem confined to a few rods or if it is a “global” problem distributed throughout many rods). FIG. 2 is a flowchart, illustrating in detail, of calculating the rod average criteria in accordance with an exemplary embodiment of the invention. As shown in FIG. 2, operation S300 may calculate the criteria by calculating at least the pin nodal exposures S310 and pin nodal powers S320 in each axial fuel node. As an exemplary embodiment, the calculated ‘pin nodals’ may be part of the rod in an axial node, and the fuel may span several axial nodes. At S310, when the operation is calculating the pin nodal exposure, the operation proceeds to S311 to average the pin exposures. The average may be obtained by averaging the pin nodal exposures with a weight factor to preserve the rod's energy. Then, at S312, the operation determines whether the weight factor is based on the nodal weight or the pin weight. If the weight factor is based on the nodal weight, then the operation proceeds to S313 (option 1), which preserves the rod energy in the nodal sense. Nodal sense may mean the weight factor is total weight of interest in the node. For example, when exposure is in terms of MWD/MTU, the weight of interest is the weight of uranium in the unburned fuel. If the weight factor is based on the pin weight, then the operation proceeds to S314 (option 2), which may be exact for preserving rod energy. In this exemplary case, the pin exposure is in terms of the weight of uranium, for example, in the pin only, and not the entire node. Thus, the rod average exposure may be employed between option 1 or 2. At S320, when the operation is calculating the pin nodal power (kW/ft), the operation proceeds to S321 to average the pin powers. The averaging may be achieved by averaging an axial average for each rod in the assembly. This may give an estimate of the average power (kW/ft) over the entire span of the rod. FIG. 3 is a flowchart illustrating in detail of developing and generating the output criteria in accordance with an exemplary embodiment of the invention. As shown in FIG. 3, operation S500 may develop and generate a two-dimensional (2D) map for outputting all fuel assemblies. The generated output may be obtained by determining the peak rod average exposure (S510), the peak rod average power (kW/ft) (S520), the ratio of peak rod average power (kW/ft) to its limit (S530), and rod average exposure and power (kW/ft) in selected assemblies (S540). If the operation determines to develop the peak rod average exposure S510, then the operation proceeds to S511 to develop the rod average power (kW/ft) for the rods in S510. Accordingly, at S512, a 2D core map is generated for the rods in S510. If the operation determines to develop the peak rod average power (kW/ft) S520, then the operation proceeds to S521 to develop the rod average exposure for the rods in S520. Accordingly, at S522, a 2D core map is generated for the rods in S520. If the operation determines to develop a ratio of peak road average power (kW/ft) to its limit, then the operation proceeds to S530. At S530, the ratio-to-limit map will be performed. Only locations where the rod average exposure is greater than the exposure limit for AST, will have a number greater than zero (otherwise it will be zero). A map, such as this, may be driven by the AST criterion, which kicks in for the peak rod average power (kW/ft) (for example, 6.3 kW/ft), only when the rod average exposure exceeds a certain value (for example, 54,000 MWD/MTU). Accordingly, at S531, a 2D core map is generated for the rods in S530. If the operation determines to develop the rod average exposure and rod average power (kW/ft) in only selected assemblies, then the operation proceeds to S540. As an exemplary embodiment, a 10×10 2D map of rod average exposure and rod average power (kW/ft) in a selected 10×10 rod assembly may be outputted. Information to this level of detail may be essential during the design phase, where one may be interested in further process of the 2D maps in selected assemblies to determine the magnitude and extent of the problem (i.e., if it is a “local” problem confined to a few rods or if it is a “global” problem distributed throughout many rods). As part of the already established well-defined process, the pin nodal exposure and power (kW/ft) may be calculated for each rod within an axial node in an assembly. These datasets are identified as PINEXPO (IROD, JROD, KC) and PINKWFT (IROD, JROD, KC), where IROD and JROD run from 1 to N, the maximum number of rods in a N×N fuel assembly. It should be appreciated that the assembly dependency of PINEXPO and PINKWFT may be omitted. As discussed above, the process of determining PINEXPO and PINKWFT may be specific to the set of methods used. The present invention may deal with utilizing the already available data (e.g., the pin nodal exposure and power (kW/ft)) to get the rod average exposure and the rod average power (kW/ft) in each fuel assembly for all rods, including up to N×N. Performing an axial averaging for each rod in the assembly may give the rod average quantities. An exemplary embodiment for calculating the rod-average exposure APINEXPO (IROD, JROD) may be obtained as follows: APINEXPO ⁡ ( IROD , JROD ) = ∑ K = 1 K = MKC ⁢ WTNODE ⁡ ( KC ) ⁢ δ ⁡ ( KC ) PINEXPO ⁡ ( IROD , JROD , KC ) ∑ K = 1 K = MKC ⁢ WTNODE ⁡ ( KC ) ⁢ δ ⁡ ( KC ) In the equation above, MKC is the total number of axial nodes. The rod average exposure APINEXPO (IROD, JROD) may be obtained as an axial (node-wise) weighting of the pin nodal exposures. Accordingly, the nodal mass WTNODE (KC) may be used as a weighting parameter (in units of metric ton of Uranium—MTU), and may approximately conserve the total energy in the rod (in units of MWD—Mega Watt-Days) in an assembly-weighted nodal sense, to obtain the rod average exposure (MWD/MTU). This may be a reasonable approach because during core depletion, as the reactor fuel burns, the fuel exposure tracking is usually on a nodal basis, and not on a pin nodal basis. The function δ(KC) may be defined as follows:δ(KC)=1.0 if PINEXPO(IROD,JROD,KC)>0.0δ(KC)=0.0 if PINEXPO(IROD,JROD,KC)≦0.0 This may ensure that the axial averaging may include only the nodes in which rod actually exists. This may be particularly relevant for part-length rods that do not extend all the way to the top in the active core. It should be appreciated that the characterization of APINEXPO above may be the “nominal” definition. In an alternative exemplary embodiment, the pin nodal mass WTPIN (KC) may be used as the weighting parameter, to represent an “alternate” definition of APINEXPO, for example: APINEXPO ⁡ ( IROD , JROD ) = ∑ K = 1 K = MKC ⁢ WTPIN ⁡ ( KC ) PINEXPO ⁡ ( IROD , JROD , KC ) ∑ K = 1 K = MKC ⁢ WTPIN ⁡ ( KC ) This approach may be particularly relevant when fuel pin weights may be readily traceable and/or if fuel exposure tracking may be on a pin nodal basis. It should be appreciated that this approach may add further detail to the modeling and to the definition of the rod-average exposure. An exemplary embodiment for calculating the rod-average power (kW/ft) APINKWFT (IROD, JROD) may be obtained as follows: APINKWFT ⁡ ( IROD , JROD ) = ∑ K ⁢ = ⁢ 1 ⁢ K ⁢ - ⁢ MKC ⁢ DELTAZ ⁡ ( KC ) ⁢ δ ⁡ ( KCF ) PINKWFT ⁡ ( IROD , JROD , KC ) ∑ K = 1 K = MKC ⁢ DELTAZ ⁡ ( KC ) ⁢ δ ⁡ ( KC ) The above equations for APINEXPO and APINKWFT may calculate the rod average exposure and rod average power (kW/ft). Further, determining the maximum value for the N×N rods in each assembly may calculate the peak rod average exposure, the rod average power (kW/ft) for that rod, the peak rod average power (kW/ft) and, the rod average exposure for that rod Once constraint data is available, developing the 2D maps may be a straightforward process so as to make the data available for further use in the design, optimization, licensing, and/or monitoring tools. Exemplary embodiments of the present invention may define a systematic method of calculating the constraints in each fuel assembly. Further, exemplary embodiments of the present invention may employ methods to operate design, optimization, licensing, and/or monitoring applications in a general and flexible manner based on the averaging of weighted (axially) nodal quantities. Further, exemplary embodiments of the present invention may not be dependent on any particular set of methodologies. The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.
043354661	abstract	A new apparatus is used to substantially instantaneously obtain a profile of an object, for example a spent fuel assembly, which profile (when normalized) has unexpectedly been found to be substantially identical to the normalized profile of the burnup monitor Cs-137 obtained with a germanium detector. That profile can be used without normalization in a new method of identifying and monitoring in order to determine for example whether any of the fuel has been removed. Alternatively, two other new methods involve calibrating that profile so as to obtain a determination of fuel burnup (which is important for complying with safeguards requirements, for utilizing fuel to an optimal extent, and for storing spent fuel in a minimal amount of space). Using either of these two methods of determining burnup, one can reduce the required measurement time significantly (by more than an order of magnitude) over existing methods, yet retain equal or only slightly reduced accuracy.
	abstract	A method of controlling the criticality of a nuclear fuel cycle facility includes steps of producing a reactor fuel by adding less than 0.1% by weight of gadolinia to a uranium dioxide powder with a uranium enrichment of greater than 5% by weight and controlling the effective neutron multiplication factor of a uranium dioxide system in a step of handling the reactor fuel to be less than or equal to the maximum of the effective neutron multiplication factor of a uranium dioxide system with a uranium enrichment of 5% by weight.
046559906	abstract	Improvements to guide tubes for the fuel assemblies of light water nuclear reactors, said assemblies being immersed in operation in the cooling water of the core of such a reactor, the guide tubes being of the type made from zircaloy and fixed at their two ends respectively to an upper end part and a lower end part made from stainless steel or Irconel and which incorporate devices for braking the fall of the control rods which they house during the rapid shutdown of the reactor, wherein the said braking devices are constituted by means for restricting the diameter of the guide tubes comprising for each guide tube a zircaloy inner sleeve spot welded to the said guide tube and whose internal diameter permits the passage, with a calibrated clearance, of the corresponding control rod, the sleeve being distributed over the lower portion of each guide tube and associated with orifices made in the actual guide tubes to produce the progressive hydraulic absorption of the end of the fall of the control rods.. The invention also relates to a process for the disassembly of the guide tubes of a fuel assembly.
045377405	description	DETAILED DESCRIPTION The invention acts on a stream of reactor coolant immediately after passage through the fuel core of the reactor. A first embodiment is illustrated schematically in FIG. 1. A stream of coolant 1 from the core, containing entrained gas bubbles 15 enters from the bottom. A cylindrical filter element 2, with a pore 3 size of <100.mu. meters, would be wetted by the coolant as it passes through filter 2. When an entrained fission gas bubble 15 contacts filter 2 in the vicinity of a pore 3, (it must displace the liquid in the pore to pass) then a balance of forces is set up between the liquid, solid filter and gas interfaces as illustrated schematically in the expanded view of FIG. 2. As the gas attempts to pass through pore 3 it exerts a pressure .DELTA.P over the pore opening forming a miniscus with contact angle .theta.. The balance of forces may be expressed: EQU .DELTA.P.pi.r.sup.2 =2.pi.r.sigma. cos .theta.; .sigma.=surface tension (dynes/cm) (1) For the bubble to pass through pore 3, .DELTA.P must be large enough to that .theta..fwdarw.0 (cos .theta..fwdarw.1). For pressure drops below this value the gas will accumulate in annulus 4 near the upper end of the filter. As the gas accumulation continues it will tend to expand and displace the fluid-gas interface 5 downward. This would tend to decrease the useful surface area of the filter which would increase the pressure drop and decrease the total liquid flow through the filter. To prevent gas blanketing of an excessive area of the filter, the gas could be bled-off through outlet 6. Alternatively the system may be designed to allow the gas blanket accumulation to increase the pressure drop across the filter to the critical pressure and start to force some of the accumulate gas through the filter. Any subsequent gas bubbles arriving with the coolant would continue to mix with the gas blanket but a bleed of the gas blanket would pass through the filter. In general it is preferred to periodically draw off the accumulated gas to check for fission gas. The actual volume of fission gas released from a breached rod is relatively small (<<1l) and the system could be operated in a continuous "feed and bleed" mode in which a stream of inert gas would be added to the coolant stream upstream from the filter at inlet 7 and continuously bled-off at outlet 6 to provide a continuous gas sample stream. This sample would be enriched in fission gas when rod failure occurred. The "feed and bleed" mode would also provide a sparging action to disengage any dissolved fission gas. After the gas was drawn off it would be routed past a scintillation detector and mass spectrometer for conventional analysis. The system could be designed to accommodate the desired coolant flow rate with a pressure drop across the filter below the critical pressure drop which would force gas through pores 3. This would be accomplished by proper selection of the pore size and filter surface area. Sample Calculation The critical .DELTA.P may be calculated from equation (1) for a given value of r and .sigma. EQU .DELTA.P.sub.c =[(2.sigma. cos .theta.)/r].fwdarw.(2.sigma./r) for cos .theta..fwdarw.1 For liquid sodium at 500.degree. C., .sigma.=210 dynes/cm. For a 10 .mu.m pore diameter r=5.times.10.sup.-4 cm. (r=radius of pore) EQU .DELTA.Pc=8.2.times.10.sup.5 dynes/cm.sup.2 .congruent.11 psi. A second embodiment is illustrated schematically in FIG. 3. The device locates a filter 10, of relatively small area, in a tube 11 at a high point in a fission gas disengagement device. Typically this would be in or near the upper end of each fuel assembly in the reactor. During initial operation all filters would be wetted by the coolant and coolant would flow through tube 11. The flow rate through tube 11 would be comparable to that through an equal area of filter on the main gas disengagement filter 13. If a fuel element should rupture and leak fission gas, the gas disengagement device on the assembly will intercept some representative fraction (say 10 to 20%) of the assembly effluent and will strip the entrained gas bubbles from it. The buoyant forces on the entrapped gas will tend to concentrate it at the upper end 12 of the disengagement device where the small tube filter 10 is located. The accumulation of gas will lead to gas blanketing of the small filter 10 and ultimately complete blockage of coolant flow through small tube 11. A device (not shown) such as an eddy current sensor would monitor the accumulation of fission gas intercepted by the larger filter. A wide range of gas detection methods or associated sodium displacement measurements may be applied. If the device is located within the upper end of the fuel assembly, the sipping devices (17) could be mated to the outlet nozzle (16) to sample for accumulated gas. If the device were located above the fuel assembly it could contain sensors such as eddy current devices to detect the accumulation of gas below the small filter. This would permit continuous remote monitoring of each fuel assembly. The sipping operation could be performed immediately after detection of gas by the sensor or it might be delayed to some more convenient time such as a scheduled shutdown. Then each of the assemblies containing leaking rods could be identified, verified and removed. The presence of several leakers or even the simultaneous occurrence of several leakers would not interfere with identification. Since the inventory of released gas would be retained by the filter until sampling was performed, there would be not need to immediately identify the leaker when it occurs (as in the case of gas tagging). Similarly, if the gas sampling and analysis system was down when one or more of the leaks occur, there is no irreversible loss of identification capability. Since the device accumulates the fission gas over the entire period the assembly operates in the breached condition, it does not depend on inducing fission gas release from the breached rods at the time of sampling. For the sipping operation the sipping device 17 would be mated to the filter tube outlet 16 or the sipping system could be permanently attached to the outlet nozzle as part of a stationary sipping system with a common manifold system or rotary selector valve. By rapidly drawing on this tube the critical pressure drop across the small filter would be exceeded and the accumulated gas would be drawn through the filter up into the gas sampling stage where it could be analyzed to confirm the presence of fission gas and determine the amount. The gas accumulation monitoring in the tubes provides a simple and rapid method for fuel failure detection and location. The sipping procedure allows the verification of leaker identity. The filter device is a simple passive unit with no moving parts. EXAMPLE In a typical installation, (see FIG. 3) the main gas disengagement filter for a full size fuel assembly could be a cylinder 18 3-inch in diameter by 6-inches long surrounding 12 tubular filters 13 0.5-inch diameter by 6-inches long. This would provide approximately 1 ft.sup.2 of filter surface. A deflector cone 19 would be designed to create approximately 5 psi pressure drop across the filter when the full assembly flow was at its rated 500 gpm. A 10 .mu.m scintered stainless steel filter will allow about 20 gpm/ft.sup.2 /psi pressure drop. Then the 5 psi across 1 ft.sup.2 would accommodate 100 gpm flow or about 20% of the total fuel assembly flow. With good mixing in the assembly it can be assumed about 20% of the released gas would be intercepted by the main filters. Even if only 10 ml of gas were released by the breached rod, the 2 ml captured by the gas disengagement filter would be enough to gas blanket the small filter. During the sipping operation application of >10 psi pressure drop across the filter would draw the gas through the filter.

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