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	abstract	An X-ray emitting section 22 for emitting soft X-ray is arranged facing a chamber 21. An inlet duct 23 and a outlet duct 24 are arranged on both sides of the chamber 21. An irradiating region is ionized by the soft X-ray. It is therefore possible to achieve a charging device of aerosol particles that is safe and easy to handle.
	summary
044656530	description	DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Description is now given with reference to FIGS. 1, 2 and 3 of a fast breeder embodying this invention in which liquid sodium is applied as a coolant. Reference numeral 10 denotes a reactor vessel containing a core 14 mounted on a support board 16. An upper plenum chamber 18 is provided above the core 14. A lower plenum chamber 20 is formed below the core 14. The upper opening of the reactor vessel 10 is covered with a shielding plug 22. An upper core structure 24 is formed below the shielding plug 22 in a state facing the upper surface of the core 14. The primary coolant flows into the reactor core 14 from the lower plenum chamber 20, is heated to a high temperature while passing through the core 14, and enters the upper plenum chamber 18. In the reactor vessel 10, a plurality of vertically extending cylindrical intermediate heat exchangers 26 are arranged substantially around the periphery of the circular core 14, with the lower end of the respective heat exchangers 26 penetrating the core support board 16. A primary coolant inlet 28 is formed at that part of the vertically extending cylindrical heat exchanger 26 which is positioned below the level of the primary coolant held in the upper plenum chamber 18. A primary coolant outlet 30 is provided at the lower end of the heat exchanger 26. Hot primary coolant drawn out of the core 14 into the upper plenum chamber 18 flows into the intermediate heat exchanger 26 at the inlet 28. In the heat exchanger 26, heat exchange takes place between the primary and secondary coolants. The primary coolant whose temperature has now fallen runs through the outlet 30 into a lower plenum chamber 32 provided in the lower part of the reactor vessel 10 which is positioned below the core support board 16. Provided above the core support board 16 is a partition wall 34 which is shaped as a whole in the annular form and whose segments substantially surround the outer half periphery of each cylindrical heat exchanger 26. A vertically extending plenum chamber 36 which is shaped substantially in annular form is provided between the partition wall 34 and the inner wall of the reactor vessel 10. The primary coolant drawn out of the intermediate heat exchanger 26 into the plenum chamber 32 below the reactor vessel passes through a port 38 (FIG. 3) formed in the reactor support board 16 into the annular plenum chamber 36. A plurality of primary coolant circulation pumps 40 are provided outside of the reactor vessel 10. The annular plenum chamber 36 is made to communicate with the suction side of the primary coolant circulation pump 40 by means of a primary coolant outlet pipe 42. The discharge side of the primary coolant circulation pump 40 and lower plenum chamber 32 communicate with each other by means of a primary coolant inlet pipe 44. The primary coolant whose temperature has fallen and which has entered the annular plenum chamber 32 is conducted to the circulation pump 40 through the outlet pipe 42 and discharged from the circulation pump 40 in a highly pressurized state. The highly pressurized primary coolant is sent to the lower plenum chamber 20 through the inlet pipe 44, and then to the core 14. With a nuclear reactor embodying this invention which is constructed as described above, the primary coolant discharged from the circulation pump 40 passes through the inlet pipe 44, and lower plenum chamber 20 into the core 14. The primary coolant which has passed through the core 14 with an increase in temperature runs into the upper plenum chamber 18, and falls in temperature due to heat exchange with the secondary coolant during passage through the intermediate heat exchanger 26. The primary coolant whose temperature has now dropped flows into the lower plenum chamber 32, and then through the annular plenum chamber 36 and outlet pipe 42 back to the circulation pump 40. The primary coolant which has traveled through the aforementioned route has covered the whole of its circulation course, and is brought to a state ready for succeeding circulation. According to the above-mentioned circulation course of the primary coolant, only the intermediate heat exchangers 26 are set in the reactor vessel 10, and the primary coolant circulation pumps 40 are disposed outside of the reactor vessel 10. Therefore, the reactor vessel 10 can be rendered appreciably compact as in the conventional loop type reactor, and can be manufactured easily. Since only the primary coolant circulation pumps 40 are installed outside of the reactor vessel 10, it is possible to reduce the length of the outlet pipe 42 and inlet pipe 44 of the primary coolant, both being located outside of the reactor tank 10. Further, these outlet and inlet pipes 42, 44 allow for the passage of only the primary coolant which has passed through the intermediate heat exchangers 26 and whose temperature has dropped, making it possible to alleviate the thermal conditions to be taken into account in designing a nuclear reactor, and consequently facilitating the design and manufacture of pipes and simplifying their entire arrangement. Further, the primary coolant circulation pumps 40 built outside of the reactor vessel 10 can be simplified in construction and installation, assuring easy maintenance and repair of said circulation pumps 40 and intermediate heat exchangers 26. The foregoing description refers to only one embodiment of this invention. It will be noted that the invention is not limited to said embodiment. For instance, the aforementioned partition wall and plenum chambers need not always be provided.
	description	This application is a Continuation of U.S. patent application Ser. No. 12/360,795, filed Jan. 27, 2009, now issued as U.S. Pat. No. 8,009,794, entitled “METHODS, APPARATUS, AND COMPUTER-PROGRAM PRODUCTS FOR INCREASING ACCURACY IN CONE-BEAM COMPUTED TOMOGRAPHY,” which claims benefit under 35 USC 119(e) of U.S. Provisional Patent Application No. 61/024,903, filed Jan. 30, 2008, both of which are incorporated herein by reference in their entirety for any and all purposes. Cone beam (CB) computed tomography (CT) involves the imaging of the internal structure of an object by collecting several projection images (“radiographic projections”) in a single scan operation (“scan”), and is widely used in the medical field to view the internal structure of selected portions of the human body as well as in the industrial and security fields to perform non-destructive inspection and to detect contraband and weapons in security screening. Typically, several two-dimensional projections (which are images) are made of the object, and a three-dimensional representation of the object is constructed from these projections using various tomographic reconstruction methods. From the three-dimensional data sets, conventional CT slice images through the object can be generated. The two-dimensional projections are typically created by transmitting radiation from a “point source” through the object, which will absorb some of the radiation based on its size and density, and collecting the non-absorbed radiation onto a two-dimensional imaging device, or imager, which comprises an array of pixel detectors (simply called “pixels”). Such a system is shown in FIG. 1. Typically, the point source and the center of the two-dimensional imager lie on a common axis, which may be called the projection axis. The source's radiation emanates toward the imaging device in a volume of space approximately defined by a right-circular cone, with roughly circular- or ellipse-shaped cross sections perpendicular to the axis (where deviations are caused by non-ideal aspects that include the heel effect in X-ray sources), having its vertex at the point source and its base at the imaging device. This is the reason the radiation is often called cone-beam (CB) radiation. The imagers in state-of-the-art CBCT systems measure around 30 cm by 40 cm, having approximately 750 rows of pixels with approximately 1,000 pixels in each row, for approximately 750,000 pixels. Generally, when no object is present within the cone, the distribution of radiation is substantially uniform on any roughly circular or elliptical area on the imager that is centered about the projection axis, and that is within the cone. However, the shape of the radiation boundary on the imager may be non-uniform, from a large number of perturbations, so that there is no perfect rotational symmetry about the projection axis. In any event, any non-uniformity in the distribution can be measured in a calibration step and accounted for. The projection axis may not be at the center of the imager or the center of the object. It may pass through them at arbitrary locations including very near the edge. In an ideal imaging system, rays of radiation travel along respective straight-line transmission paths from the source, through the object, and then to respective pixel detectors without generating scattered rays. However, in real systems, when photons of X-radiation in rays interact with a portion of the object (including photoelectric, Compton and pair production interactions), one or more scattered rays are often generated that deviate from the transmission path of the incident radiation. These scattered rays are often received by “surrounding” pixel detectors that are not located on the transmission path that the initial photon-containing-rays of radiation was transmitted on, thereby creating errors in the electrical signals of the surrounding pixel detectors. Also, in typical two-dimensional imagers, the radiation meant to be received by a pixel is often scattered by various components of the source-imager system (e.g., scintillation plate, bow tie filters, radiation hardening filters, the metal anode that electrons hit in the source to produce X-rays etc.), and received by surrounding pixels. These effects are often characterized, in part, by a point-spread function (PSF), which is a two-dimensional mapping of the amount of error caused in surrounding pixels by a given amount of radiation intended for a central pixel. The surface of the PSF is similar to the flared shape of a trumpet output, with the greatest amount of error occurring in pixels adjacent to the central pixel. Each of the above non-ideal effects creates spatial errors in the pixel data generated by the two-dimensional imager. In turn, the spatial errors cause artifacts (e.g., phantom images) and loss of resolution and contrast and blurring in the CBCT image slices produced by the radiation imaging system. As part of making his inventions, the inventor has recognized that, while radiologists and physicians use CBCT imaging to obtain broad images of a patient's torso during the initial portion of the diagnostic phase, they often focus their attention to specific areas of the images, such as to parts of specific organs, during the latter portion of the diagnostic phase and/or treatment phase. As also part of making his inventions, the inventor has discovered that the accuracy of the images generated from CBCT can be greatly improved by obscuring portions of the radiation source so that the radiation only passes through the specific areas of the patient related to the regions-of-interest to the doctor. The obscuring action causes less radiation to pass through the patient's body, which in turn causes the radiation to undergo less scattering through the patient's body, thus reducing a major source of error in the image accuracy. The obscuring action may be performed with bodies of material that absorb at least 60 percent of the incident radiation (and up to 100 percent); total absorption of the incident radiation is not necessary although it is sometimes preferred. Thus, as used herein, the action of obscuring a portion of a radiation beam means absorbing at least 60 percent of the incident radiation, or initial value, of that portion, and up to 100 percent thereof. The obscuring action also causes the radiation to strike a smaller portion of the two-dimensional imager. The use of less than the full area of the two-dimensional imaging device is contrary to conventional wisdom and practice in the art, which teaches artisans, physicians, and radiologists to use the full extent of the two-dimensional imager. For this reason, the prior art teaches against the present invention. The obscuring action may be done along either or both of the axial and trans-axial dimensions of the imager (the axial dimension is parallel to the rotation axis of the gantry, and the trans-axial dimension is perpendicular to the axial dimension). If the obscuring action is only done along the axial dimension, then standard 3-D reconstruction methods may be used; this is often the preferred manner of obscuring the beam. If the obscuring action is done along the trans-axial dimension (also called the lateral dimension), then truncated 3-D reconstruction methods may be used to just reconstruct limited volumes of the object being imaged. In further preferred implementations of the present inventions, an estimate of the scattered radiation may be generated from the measured pixel data of selected pixels that lie outside of the illuminated area. The scatter estimate may be subtracted from, or otherwise factored out of, the CT data set to further improve the accuracy of the data. A first general invention of the present application is directed to a method of operating a cone-beam CT scanning system, the system having a two-dimensional pixel array with a number Xpix of pixels in a first dimension that is perpendicular to the system's axis of rotation and a number Ypix of pixels in a second dimension that is parallel to the system's axis of rotation, Xpix being greater than one hundred and Ypix being greater than ten. The system further has a source of radiation that emits a cone-beam of radiation that normally covers all of the pixels of the pixel array. Broadly stated, the method comprises positioning an object between the source of radiation and the pixel array, obscuring a portion of the cone beam of radiation such that direct rays of the radiation cover less than 85 percent of the area of the pixel array and span at least three percent of the second dimension in a portion of the pixel array, and obtaining a plurality of projections of the object with the cone beam obscured, the plurality of projections being taken at a corresponding plurality of relative angles between the object and the source of radiation. The obscuring action may be done by placing a collimator (e.g., one or more sets of fan blades) between the radiation source and the object. A second general invention of the present application is directed to a method of operating a cone-beam CT scanning system, the system having a two-dimensional pixel array with a number Xpix of pixels in one of the dimensions and a number Ypix of pixels in the other dimension, Xpix being greater than one hundred and Ypix being greater than ten. The system further has a source of radiation that emits a cone-beam of radiation that normally covers all of the pixels of the pixel array. Broadly stated, the method comprises determining an extent of the pixel array that will receive direct-path radiation passing through a target volume of the object during a rotational scan of the object, the rotation scan including a plurality of projections of the object taken at a corresponding plurality of relative angles between the object and the source of radiation, the extent of the angles being equal to or greater than 180 degrees, and the target portion being smaller than the size of the object. The method further comprises obscuring a portion of the cone beam of radiation such that direct rays of the radiation cover at least the determined extent, but less than 85 percent of the pixel array. The obscuring action may be done by placing a collimator (e.g., one or more sets of fan blades) between the radiation source and the object. Further embodiments of the method may include obtaining a plurality of projections of the object with the cone beam obscured, the plurality of projections being taken at a corresponding plurality of relative angles between the object and the source of radiation. A third general invention of the present application is directed to a method of operating a cone-beam CT scanning system, the system having a two-dimensional pixel array with a number Xpix of pixels in a first dimension that is perpendicular to the system's axis of rotation and a number Ypix of pixels in a second dimension that is parallel to the system's axis of rotation, Xpix being greater than one hundred and Ypix being greater than ten. The system further has a source of radiation that emits an un-obscured cone-beam of radiation that normally covers all of the pixels of the pixel array. Broadly stated, the method comprises obtaining a first scan of the object with the direct rays of the radiation covering at least 85 percent of the pixel array; and obtaining a second scan of the object with the direct rays of the radiation covering less than 85 percent of the pixel array and spanning at least three percent of the second dimension in a portion of the pixel array. Further preferred embodiments of this method may include generating a three-dimensional CT data set of the object from the projections of the scans using a truncated reconstruction method. A related computer-program product invention may comprise acquiring the sets of radiographic projections of these two scans and generating a three-dimensional CT data set of the object with a truncated reconstruction method. A fourth general invention of the present application is directed to a method of reconstructing projection data comprising acquiring a set of radiographic projections of an object that has been taken with a portion of the pixels being obscured from the cone-beam radiation, acquiring an indication of which pixels have been obscured, and performing a truncated reconstruction of the object using the radiographic projection and the indication of which pixels have been obscured. The action of acquiring the sets of radiographic projections may comprise receiving the sets from another entity or process, and may comprise instructing a cone-beam CT scanning system to generate the sets. The action of acquiring the indication of which pixels have been obscured may comprise receiving the indication from another entity or process, and may comprise analyzing the pixel values of the scans to determine which pixels have been obscured. Further preferred embodiments of this method may include generating estimates of scattered radiation from the data of the obscured pixels and generating corrected radiographic projections from the acquired radiographic projections and the estimates of the scattered radiation. A related computer-program product invention comprises instruction sets that direct a data processor to perform the above actions. A fifth general invention of the present application is directed to a method of processing projection data comprising acquiring a set of radiographic projections of an object that have been taken with a portion of the pixels being obscured from the cone-beam radiation, obtaining an indication of which pixels have been obscured, and generating estimates of scattered radiation from the values of the obscured pixels. The action of acquiring the sets of radiographic projections may comprise receiving the sets from another entity or process, and may comprise instructing a cone-beam CT scanning system to generate the sets. The action of acquiring the indication of which pixels have been obscured may comprise receiving the indication from another entity or process, and may comprise analyzing the pixel values of the scans to determine which pixels have been obscured. Further preferred embodiments of this method may include generating corrected projections from the radiographic projections and the estimates of the scattered radiation. A related computer-program product invention comprises instruction sets that direct a data processor to perform the above steps. A sixth general invention of the present application is directed to a cone-beam CT scanning apparatus. Broadly stated, the apparatus comprises a two-dimensional pixel array with a number Xpix of pixels in an axial dimension and a number Ypix of pixels in a trans-axial dimension, Xpix being greater than one hundred and Ypix being greater than ten, a source of radiation that emits a cone-beam of radiation that normally covers all of the pixels of the pixel array, a collimator disposed closer to the source of radiation than the two-dimensional pixel array and that is selectively moveable to obscure at least one portion of the cone-beam, a first positioner that positions the collimator in response to a first set of at least one control signal, and a controller that generates the first set of at least one control signal. In one preferred embodiment, the collimator comprises a first set of fan blades that are selectively moveable to obscure one or both sides of the cone-beam, and the first positioner positions the first set of fan blades in response to the first set of at least one control signal. The edges of the fan blades of the first set are oriented substantially perpendicular to the scan axis, and are substantially parallel with the trans-axial dimension of the imaging device. With this configuration of this preferred embodiment, the first set of fan blades can selectively obscure pixels in the axial (Ypix) dimension. Further preferred embodiments further comprise a second set of fan blades that are selectively moveable to obscure one or both sides of the cone-beam along the trans-axial dimension, and a second positioner that positions the second set of fan blades in response to a second set of at least one control signal, wherein the controller further generates the second set of at least one control signal. In this further preferred embodiment, the edges of the fan blades of the second set are oriented substantially parallel to the scan axis, and are substantially perpendicular to the axial dimension of the imaging device. The obscuring of the cone beam according to the present invention reduces the field of view of the image, but improves image accuracy in the field of view. A reconstructed three-dimensional CT data set models the radiation attenuation coefficient of the object's material at a three dimensional array of locations, called voxels (which is shorthand for “volume pixels”). As a ray of radiation passes through the voxels of the object, its intensity decreases exponentially along the beam path. It is the small differences in the attenuation coefficients of the voxels that produce the subtle contrasts that physicians and radiologists use to image, identify, and diagnose problems. When there is a lot of scattering of the radiation rays, there is a lot of noise in the projection data, and this noise decreases the accuracy of reconstructing, and thereby measuring, each voxel's attenuation coefficient. The scattered radiation represents noise because it has been generated at unknown points in the object being imaged, and has been attenuated by unknown materials along unknown paths through the object. As part of making his invention, the inventor has recognized that scattered radiation generated at a point of the object can be dispersed over a wide area of the pixel array. The present invention reduces the overall magnitude of the scattered radiation by decreasing radiation in areas where it is not needed for the physicians and radiologists to see the subtle contrasts that they seek to examine. The improvement in the imaging quality results in more accurate Hounsfield units for the voxels. A Hounsfield unit is essentially a rescaling of the attenuation coefficient of a voxel, where a Hounsfield unit value of 0 represents the attenuation coefficient of water, and a Hounsfield unit value of −1000 represents the attenuation coefficient of air. Voxels that are more dense than water have Hounsfield units that are greater than zero, and materials that are less dense than water have Hounsfield units that are less than zero. The Hounsfield unit system provides physicians and radiologists with higher contrast perspective to see finer details since the human body is mostly water. The present inventions improve the accuracy of measured Hounsfield units by reducing radiation scattering and reducing the field of view. These and other inventions are described below in greater detail. The inventions disclosed herein may be used separately to together in various combinations, and one or more elements and features of each invention may be used in the other inventions. The inventions of the present application will be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments of the inventions are shown. This inventions may, however, be embodied in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure is thorough and complete and fully conveys the scope of the inventions to one skilled in the art. In the drawings, the relative dimensions of some elements may be exaggerated for clarity. The same reference numerals are used to denote the same elements throughout the specification. The elements may have different interrelationships and different positions for different embodiments. The terms used herein are for illustrative purposes of the present inventions only and should not be construed to limit the meaning or the scope of the present inventions. As used in this specification, a singular form may, unless definitely indicating a particular case in terms of the context, include a plural form. Also, the expressions “comprise” and/or “comprising” used in this specification neither define the mentioned characteristics, numbers, steps, actions, operations, members, elements, and/or groups of these, nor exclude the presence or addition of one or more other different characteristics, numbers, steps, operations, members, elements, and/or groups of these, or addition of these. Spatially relative terms, such as “over,” “above,” “upper,” “under,” “beneath,” “below,” “lower,” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of an apparatus in use or operation in addition to the orientation depicted in the figures. For example, if an apparatus in the figures is turned over, elements described as “below” or “beneath” or “under” other elements or features would then be oriented “over” or “above” the other elements or features. Thus, the exemplary term “above” may encompass both an above and below orientation. As used herein, terms such as “first,” “second,” etc. may be used to describe one or more members, components, characteristics, etc. However, it is obvious that the members, components, characteristics, etc. should not be defined by these terms. The terms are used only for distinguishing one member, component, characteristic, etc. from another. Thus, a first member, component, characteristic, etc. that is described may also refer to a second member, component, characteristic, etc. without departing from the scope of the present invention. System Overview. FIG. 2A is a schematic diagram of a first exemplary imaging system 100 according to the system inventions of the present application. System 100 comprises a radiation source 110, a two-dimensional imaging device 120 disposed opposite to radiation source 110 along a projection line, a first set of fan blades 130 disposed between the radiation source and the two-dimensional imaging device, a first fan-blade drive 135 that holds fan blades 130 and sets their positions. The edges of fan blades 130 are oriented substantially perpendicular to the scan axis (defined below), and are substantially parallel with the trans-axial dimension (defined below) of imaging device 120. As an option, system 100 may further comprise a second set of fan blades 140 disposed between the radiation source and the two-dimensional imaging device, and a second fan-blade drive 145 that holds fan blades 140 and sets their positions. The edges of fan blades 140 are oriented substantially parallel with the scan axis (defined below), and are substantially parallel to the axial dimension (defined below) of imaging device 120. The fan blades are examples of a collimator, and are disposed closer to radiation source 110 than imaging device 120. Examples of other collimators are provided below. System 100 further comprises a gantry 150 that holds radiation source 110, imaging device 120, and fan-blade drives 135 and 145 in fixed or known spatial relationships to one another, a mechanical drive 155 that rotates gantry 150 about an object disposed between radiation source 110 and imaging device 120, with the object being disposed between fan blades 130 and 140 on the one hand, and imaging device 120 on the other hand. The term gantry has a broad meaning, and covers all configurations of one or more structural members that can hold the above-identified components in fixed or known (but possibly movable) spatial relationships. For the sake of visual simplicity in the figure, the gantry housing, gantry support, and fan-blade support are not shown. These components do not form part of the present inventions. Also not shown is a support table for the object (i.e., an object support member), which does not form a part of the present inventions related to System 100. Additionally, system 100 further comprises a controller 160 and a user interface 165, with controller 160 being electrically coupled to radiation source 110, mechanical drive 155, fan-blade drives 135 and 145, imaging device 120, and user interface 165. User interface 165 provides a human interface to controller 160 that enables the user to at least initiate a scan of the object, to collect measured projection data from the imaging device, and to adjust the positions of fan blades 130 and 140. User interface 165 may be configured to present graphic representations of the measured data. In imaging system 100, gantry 150 is rotated about the object during a scan such that radiation source 110, fan blades 130 and 140, fan-blade drives 135 and 145, and two-dimensional imaging device 120 circle around the object. More specifically, gantry 150 rotates these components about a scan axis, as shown in the figure, where the scan axis intersects the projection line, and is typically perpendicular to the projection line. The object is aligned in a substantially fixed relationship to the scan axis. The construction provides a relative rotation between the projection line on the one hand and the scan axis and an object aligned thereto on the other hand, with the relative rotation being measured by an angular displacement value θ. Mechanical drive 155 is mechanically coupled to gantry 150 to provide rotation upon command by controller 160. The two-dimensional imaging device comprises a two-dimensional array of pixels that are periodically read to obtain the data of the radiographic projections. Imaging device 120 has an X-axis and a Y-axis, which are perpendicular to each other. Imaging device 120 is oriented such that its Y-axis is parallel to the scan axis. For this reason, the Y-axis is also referred to as the axial dimension of imaging device 120, and the X-axis is referred to as the trans-axial dimension, or lateral dimension, of device 120. The X-axis is perpendicular to a plane defined by the scan axis and the projection line, and the Y-axis is parallel to this same plane. Each pixel is assigned a discrete X-coordinate (“X”) along the X-axis, and a discrete Y-coordinate (“Y”) along the Y-axis. In typical implementations, the size of the array is 1024 pixels by 768 pixels, with the longer dimension of the array being oriented parallel to the X-axis. As used herein, the discrete X-coordinates start at 1 and end at Xpix (e.g., Xpix=1024), and the discrete Y-coordinates start at 1 and end at Ypix (e.g., Ypix=768). A smaller number of pixels are shown in the figure for the sake of visual clarity. The imaging device may be centered on the projection line to enable full-fan imaging of the object, may be offset from the projection line to enable half-fan imaging of the object, or may be movable with respect to the projection line to allow both full-fan and half-fan imaging of objects. As an example of a half-fan configuration, the imaging device may be offset from the center by 16 centimeters in its X-dimension when the imaging device has a span in the X dimension of 40 centimeters. FIG. 3 shows a perspective view of a first exemplary implementation of fan blades 130 and fan-blade drive 135. Each fan blade 130 may have a thin rectangular shape, and may comprise a material that absorbs the radiation of source 110. Such a material may comprise lead (Pb). Each fan blade 130 absorbs at least 60% of the incident radiation from radiation source 110. In preferred implementations, a fan blade absorbs at least 90 percent, and more preferably at least 99 percent, of the radiation incident upon it. Fan-blade drive 135 may comprise two mechanical positioners. In one exemplary implementation, each mechanical positioner is mechanically coupled to a respective fan blade to cause the fan blade to move in a controlled and measurable (e.g., predictable) manner. In another implementation, one of the mechanical positioners is mechanically coupled to the fan blades to cause the blades to move relative to one another so as to vary the distance of the gap between the blades in a controlled and measurable manner, and the other positioner is mechanically coupled to the blades to cause the blades to move as a group in a controlled and measurable manner. In the latter exemplary implementation, the first positioner and the fan blades may be mechanically disposed on a carriage, and the second positioner may be mechanically coupled to the carriage. Each positioner may comprise a linear motor servo, a rotating motor servo with rotation-to-linear translation mechanism, or the like. The construction of fan blades 140 and fan blade drive 145 may be the same as that of fan blades 130 and fan-blade drive 135, respectively. FIG. 4 shows a perspective view of a second exemplary implementation of fan blades 130 and fan-blade drive 135. Each fan blade 130 may comprise an eccentric cam, and may comprise a material that absorbs at least 60% of the incident radiation from radiation source 110. Such a material may comprise lead (Pb). In preferred implementations, a fan blade absorbs at least 90 percent, and more preferably at least 99 percent, of the radiation incident upon it. Each fan-blade drive 135 may comprise a rotating servo motor, preferably with a set of reduction gears, which drives the eccentric cam. Fan blades 130 may be placed in an overlapping relationship so that each may obscure more than 50% of imaging device 120. The construction of fan blades 140 and fan blade drive 145 may be the same as that of fan blades 130 and fan-blade drive 135, respectively. As used herein, the term “fan blades” has broad meaning, and covers all configurations of structural members that can provide a primary region (e.g., gap, aperture, etc.) through which radiation may pass with relatively little attenuation compared to one or more surrounding regions, and where a dimension of the primary region may be controlled and/or where the primary region may be selectively disposed toward or away from the projection line so that the primary region can be selectively disposed inside or outside of the source's radiation field that is collected by the imaging device. Also as used herein, the terms “fan-blade drive” and “positioners” have broad meanings, and cover all configurations of electro-mechanical elements that can provide the above positioning of the fan blades and other collimators. Each fan blade 130 and 140 is disposed closer to radiation source 110 than imaging device 120, and is adapted to significantly attenuate the radiation that strikes it, and to preferably substantially block it. The distal edges of fan blades 130 are preferably parallel to the X-axis of imaging device 120 and are selectively moveable, by way of fan blade drive 135, to obscure one or both sides of the cone-beam along the axial dimension. An example of the obscuring action is shown in FIG. 5, where pixels having Y coordinate values less than Y1 and greater than Y2 are substantially shielded from the radiation emitted by source 110, where Y1<Y2, and where both Y1 and Y2 are greater than 1 and less than Ypix. This is typically the preferred obscuring configuration, and leaves an imaging window through which direct-path radiation from source 110 may be received. The window is defined by the four points: (1,Y1), (1,Y2), (Xpix,Y1), and (Xpix,Y2). Similarly, the distal edges of fan blades 140 are preferably parallel to the Y-axis of imaging device 120 and are selectively moveable, by way of fan blade drive 145, to obscure one or both sides of the cone-beam along the trans-axial dimension. An example of the obscuring action is shown in FIG. 6, where pixels having X coordinate values less than X1 and greater than X2 are substantially shielded from the radiation emitted by source 110, where X1<X2, and where both X1 and X2 are greater than 1 and less than Xpix. This leaves an imaging window through which direct-path radiation from source 110 may be received, where the window is defined by the four points: (X1,1), (X1,Ypix), (X2,1), and (X2,Ypix). FIG. 7 shows an example where both sets of fan blades are positioned to obscure portions of the imaging device, leaving an imaging window through which direct-path radiation from source 110 may be received. The window is defined by the four points: (X1,Y1), (X1,Y2), (X2,Y1), and (X2,Y2). In preferred embodiments, controller 160 can send control signals to fan-blade drives to select any location and size of window desired by the operator. Referring back to FIG. 2A, when controller 160 receives a request from the user to begin a scan of an object, controller 160 instructs fan-blade drives 135 and 145 to set the fan blades 130 and 140, respectively, in given positions (as described in greater detail below), instructs mechanical drive 155 to begin a scan rotation of gantry 150, and instructs radiation source 110 to begin emitting radiation. As it rotates, mechanical drive 155 provides controller 160 with an indication of the angular displacement value θ. Controller 160 uses this information to read the values of imaging device 120's pixel detectors at selected angular displacement values θ to obtain the data for the radiographic projections. Typically, there are between 250 and 1000 projections taken in the 360-degree scan rotation, with each projection being spaced from adjacent projections by a set increment Δθ of angular displacement. The controller stores the data from each projection in a memory storage device, along with the angular displacement value θ at which the projection was taken. Controller 160 comprises a processor, an instruction memory for storing instruction sets that direct the operation of the processor, a data memory that stores pixel and other data values used by the present inventions implemented by the imaging system, and an I/O port manager that provides input/output data exchange between processor 160 and each of radiation source 110, mechanical drive 155, fan-blade drives 135 and 145, and imaging device 120. The instruction memory and data memory are coupled to the main processor through a first bidirectional bus, and may be implemented as different sections of the same memory device. Because of the large amount of data provided by the two-dimensional imaging device, the I/O port manager is preferably coupled to the main processor through a second bidirectional bus. However, the I/O port manager may be coupled to the main processor by way of the first bidirectional bus. The operation of the processor is guided by a group of instruction sets stored in the instruction memory, which is an exemplary form of computer-readable medium. Exemplary instruction sets are illustrated below. In exemplary imaging system 100 shown in FIG. 2A, the gantry rotates about the object, which means that the projection line rotates about the object and the scan axis. Instead, it may be appreciated that the object and the scan axis may be rotated while the gantry and the projection line are stationary. A second exemplary imaging system which rotates the object is shown at 100′ in FIG. 2B. System 100′ comprises all of the components of system 100, with the components being coupled to one another in the same way, except that the mechanical drive is coupled to an object support member, which holds the object being scanned. In system 100′, the gantry remains stationary while the mechanical drive rotates the object support member and the object. System 100′ is suitable for industrial uses (e.g., scanning non-human objects), whereas system 100 is suitable for medical uses (e.g., scanning human objects). Methods and Computer-Program Products. A first general invention of the present application is directed to a method of operating a cone-beam CT scanning system, such as systems 100 and 100′, and is illustrated by the flow diagram of an exemplary method 200 in FIG. 8. The exemplary method comprises positioning an object between the radiation source 110 and the imaging device 120, obscuring one or more portions of the cone-beam radiation from source 110 such that direct rays of the radiation cover 85 percent or less of the area of the pixel array and span at least three percent of the array's axial dimension (Y-axis) in at least a portion of the pixel array. These limitations can be stated mathematically as:(X2−X1)(Y2−Y1)≦0.85XpixYpix, and(Y2−Y1)≧0.03Ypix over at least a portion of the X-axis.The obscuring action may be done before or after the positioning action. A lamp emitting visible light may be substantially co-located with radiation source 110 to facilitate performing the obscuring action by illuminating the imaging window onto the object support table before the positioning action, or onto the object during the positioning action. In typical implementations, the obscuring action is performed such that direct rays of the radiation span at least fifteen percent of the array's axial dimension (Y-axis) in at least a portion of the pixel array, and more typically at least twenty percent. Also, in many typical implementations, direct rays of the radiation may cover 75 percent or less of the area of the pixel array, and 50 percent or less. In some cases, it can be lower than 35 percent. The exemplary method further comprises obtaining a plurality of projections of the object with the cone beam obscured, with the plurality of projections being taken at a corresponding plurality of relative angles θ between the object and radiation source 110. The number of projections is preferably sufficient to perform at least a truncated reconstruction of the voxel attenuation coefficients, being at least 250, preferably at least 400, more preferably at least 500, and most preferably at least 600. The actions of method 200 may be performed by an operator of system 100 (or 100′), such as a radiologist, physician, technologist, etc., and the projections may be stored in the data memory of controller 160. From there, the projections may be processed by a truncated reconstruction procedure to generate CT images of the imaged area of the object, as described below in greater detail, or may be exported to another data processor for processing. To assist the operator with performing the above obscuring and obtaining actions, the instruction memory of data processor 160 may be loaded with an exemplary computer-program product 210 shown in FIG. 9. Product 210 comprises a computer-readable medium and a plurality of instruction sets embodied on the computer-readable medium. Instruction set #1 directs data processor 160 to receive input from the operator on the desired extents of the imaging window and to set fan blades 130 and 140 at respective positions. These instructions may include a subset of instructions that direct processor 160 to receive the values of the imaging window (e.g., the values of X1, X2, Y1, and Y2); they may include a subset of instructions that direct data processor 160 to provide a graphical representation of the pixel array of device 120 to the user, and to receive inputs from the user, such as in the form of mouse clicks, to define an imaging window on the graphical representation, and to draw a representation of the imaging window on the graphical representation. The subset of instructions may further direct the data processor 160 to receive inputs from the user to modify the position of the defined imaging window. In further embodiments, this subset of instruction set #1 may include instructions that direct data processor 160 to take a projection of the object (such as with θ=0), and to display the projection on the graphical representation. This enables the operator to identify features of the object, such as bones of a patient, and to locate the imaging window with respect to the identified features. The operator can also temporarily place radiation-absorbing markers on the object (e.g., patient) that indicate the desired extent of the imaging window during this initial projection. The markers will appear on the initial scan, and the operator can set the imaging window relative to the shown markers. Instruction set #2 of product 210 directs data processor 160 to receive input from the operator to start a scan of the object. Instruction set #3 directs data processor 160 to perform the scan of the object and obtain a plurality of radiographic projections of the object at a corresponding plurality of angular displacement values θ between the object and the radiation source. Under the direction of instruction set #3, data processor 160 preferably instructs mechanical drive 155 to begin a scan rotation of gantry 150, instructs radiation source 110 to begin emitting radiation, receives indications of the angular displacement value θ from mechanical drive 155, and reads the values of imaging device 120's pixel detectors at selected angular displacement values θ to obtain the data for the radiographic projections. Instruction set #4 of computer-program product 210 directs data processor 160 to store the radiographic projections (i.e., pixel data and corresponding angular displacement value θ), in a computer-readable medium, such as the data memory of data processor 160, which may include a disk storage unit. Instruction set #4 may be performed in parallel with instruction set #3, storing each projection as it is read from imaging device 120. Product 210 may include an optional instruction set #5 that directs data processor 160 to store indications of the locations of fan blades 130 and 140 along with the projection data. This information can be stored as the extent of the imaging window (e.g., as X1, X2, Y1, and Y2), and can be useful to a truncation reconstruction procedure, which is described in greater detail below. However, the reconstruction procedure may comprise processing actions that deduce the extent of the imaging window, in which case the results of instruction set #5 are not needed. Typically the operator wishes to set the imaging window to a target area of the object (e.g., patient), such as an organ of the patient, which is generally contained within a three-dimensional volume. It is important for the operator to recognize that the position of the object and the extent of the imaging window have to be collectively set so that the target volume is irradiated during the scan of the object. In one implementation, the values X1 and X2 are set to the full extent of the imager's x-dimension (X1=1 and X2=Xpix), and fan blades 130 are adjusted with the help of the previously described illumination lamp to illuminate the desired crosssection of the object. Since the rays of the cone-beam radiation diverge, this action is generally sufficient to capture the target region as long as the scan axis runs through the object (the reader may visually verify this by looking ahead to FIG. 11). The position of the object support table and/or the height of the object over the table may be adjusted to bring the scan axis within the volume of the object. In another implementation, the object is positioned such that the target volume at θ=0 is centered on the scan axis, such as by adjusting the trans-axial position of the object to center the lateral extent of the target volume about the scan axis, and adjusting the height of the object support table to center the thickness of the target volume about the scan axis. In this case, the axial extent of the target volume need only be located within the axial extent of imaging device 120. However, if desired and if possible, the axial position of the object may be adjusted so as to center the axial extent of the target volume about the position of the projection axis at θ=0. These adjustment actions may be done by the operator as a further embodiment of method 200, described above. Once the target volume has been centered about the scan and projection axes, the extent of the imaging window may be determined as follows, and as illustrated by the trans-axial crosssection of the system shown in FIG. 10. The target area measures 2Δx by 2Δy by 2Δz, where Δx, Δy, and Δz can have different values, and where the dimension 2Δy is perpendicular to the page. In order to provide reconstructed voxel values in the target volume, the width of the imaging window in the X-dimension should be set to 2ΔX=2rD/d, where r=[Δx 2+Δz2]1/2, where D is the shortest distance between radiation source 110 and imaging device 120, and where d is the distance between radiation source 110 and the scan axis. This can be deduced by applying geometric principles to the construction shown in the figure. X1 and X2 may then be set to X1=(Xpix/2−ΔX) and X2=(Xpix/2+ΔX). If it is not possible to center the x- and z-dimensions of the target value about the scan axis, then one may expand the size of the volume shown in the figure, in either one or both of the x- and z-dimensions, so as that the expanded volume encompasses the target volume, and then work with the expanded volume instead of the target volume. This approach can be taken when it is not possible to adjust the height of the object with respect to the support table. FIG. 11 shows the axial crosssection of the system with the target volume centered about the scan axis and the projection axis. During the scan of the object, there will be angles at which the some edges of the target volume will be at a distance of (d−r) from radiation source 110, as illustrated by dashed lines in the figure. In order to provide reconstructed voxel values in the target volume, the width of the imaging window in the Y-dimension should be set to 2ΔY=2ΔyD/(d−r), which can be deduced by applying geometric principles to the construction shown in the figure. Y1 and Y2 may then be set to Y1=(Ypix/2−ΔY) and Y2=(Ypix/2+ΔY). The value of r may be based on the dimensions of the target volume, or the above-described expanded volume if it is not possible to center the target volume about the scan axis. If it is not possible or desirable to center the y-dimension of the target volume about the projection axis, an offset may be added to the Y1 and Y2 values. For example, if the y-dimension of the target value is offset by a value Δb from the projection axis, then a value of ΔB may be added to both Y1 and Y2, such as Y1=(Ypix/2−ΔY+ΔB) and Y2=(Ypix/2+ΔY+ΔB), where ΔB=ΔbD/(d−r). Δb has a positive value when the target volume is offset toward Y=Ypix, and a negative value when the target volume is offset toward Y=1. As a point of generality, we may refer to the point (Xpix/2, Ypix/2) as (Xc,Yc), where the latter is defined as the point where the projection axis intersects the pixel array. If y1 and y2 are the extend of the target volume, as measured relative to the center point where the projection axis and scan axis intersect, then Δy may be generated as the absolute value of the difference between y1 and y2, and Δb may be generated as (y1+y2)/2. Instruction set #1 of product 210 described above may comprise a subset of instructions that receives the extent of the target volume from the operator and computes the values X1, X2, Y1, and Y2 of the imaging window. The extent of the x- and y-dimensions of the target volume may be input by numeric values relative to a predefined measuring point, or may be obtained through the above-described graphical interface that shows the user an initial projection at θ=0 and enables the user to define a box on the graphical interface (the subset of instructions may then back-project the box to the plane of the scan axis using simple geometric operations). The z-dimension may be input as numeric values relative to the top of the object support table by the operator, and corrected for the distance between the scan axis and the table top. In some implementations, the subset of instructions may take a second projection of the object at θ=90, and provide the operator with a graphic representation of the second projection and graphic interface that enables the operator to define the z-dimension (the subset of instructions may then back-project this input to the plane of the projection axis using simple geometric operations). With this information, the subset of instructions may expand the target volume to account for any off-centering of the target volume, and then compute the image window with the actions previously described above. The paragraphs describing FIGS. 10 and 11 illustrated various actions that can be taken to determine (e.g., find) the extent of the pixel array that will receive direct-path radiation passing through a target volume of the object during a rotational scan of the object. This determination action actually comprises a part of another invention of the present application, which is described next with reference to the method flow diagram illustrated in FIG. 12. This invention relates to a method of operating a cone-beam CT scanning system, such as systems 100 and 100′, which is illustrate by exemplary method 220 (FIG. 12). Method 220 comprises determining an extent of the pixel array that will receive direct-path radiation passing through a target volume of the object during a rotational scan of the object, the rotation scan including a plurality of projections of the object taken at a corresponding plurality of relative angles between the object and the source of radiation, the extent of the angles preferably being equal to or greater than 180 degrees, and the target portion being smaller than the size of the object. The extent may be determined by taking actions described in the three previous paragraphs. Method 220 further comprises obscuring one or more portions of the cone beam of radiation such that direct rays of the radiation cover at least the determined extent, but 85 percent or less of the pixel array. The obscuring action may be done by placing a collimator and/or one or more fan blades (e.g., fan blades 130 and/or 140) between the radiation source and the object. This action typically further comprises providing an imaging window in which the direct rays span at least three percent of the array's axial dimension, and more typically at least 15 to 20 percent of the array's axial dimension. Also, in many typical implementations, direct rays of the radiation may cover 75 percent or less of the area of the pixel array, and 50 percent or less. In some cases, it can be lower than 35 percent. The exemplary method 220 further comprises obtaining a plurality of projections of the object with the cone beam obscured, with the plurality of projections being taken at a corresponding plurality of relative angles θ between the object and radiation source 110. The number of projections is preferably sufficient to perform at least a truncated reconstruction of the voxel attenuation coefficients. The actions of method 220 may be performed by an operator of system 100 (or 100′), such as a radiologist, physician, technologist, etc., and the projections may be stored in the data memory of controller 160. From there, the projections may be processed by a truncated reconstruction procedure to generate CT images of the imaged area of the object, as described below in greater detail, or may be exported to another data processor for processing. Truncated reconstruction methods have been widely developed and used in the art for the case where the object is larger than the area of the two-dimensional imaging device. While these truncated reconstruction methods were not developed with the present inventions in mind, they may be readily adapted to process the projection data collected by the present inventions without undue experimentation by those of ordinary skill in the art. Papers and patents describing truncated reconstruction methods can be readily located by searching the Internet and free-access patent databases with the search terms “truncated reconstruction” and “tomography.” U.S. Pat. Nos. 5,640,436 and 6,542,573, and published PCT application WO-2005-104038 A1 provide examples of truncated reconstruction methods, and are incorporated herein by reference. Yet another general invention of the present application is directed to a method of operating a cone-beam CT scanning system, such as systems 100 and 100′, the system having a two-dimensional pixel array with a number Xpix of pixels in a first dimension that is preferably perpendicular to the system's axis of rotation and a number Ypix of pixels in a second dimension that is preferably parallel to the system's axis of rotation, Xpix being greater than one hundred and Ypix being greater than ten. The method is illustrated at 240 in FIG. 13, and comprises obtaining a first scan of the object with the direct rays of the radiation covering at least 85 percent of the pixel array, and obtaining a second scan of the object with the direct rays of the radiation covering less than 85 percent of the pixel array and spanning at least three percent of the second dimension in a portion of the pixel array. This action typically further comprises providing an imaging window in the second scan in which the direct rays span at least three percent of the array's axial dimension, and more typically at least 15 to 20 percent of the array's axial dimension. Also, in many typical implementations, direct rays of the radiation in the second scan may cover 75 percent or less of the area of the pixel array, and 50 percent or less. In some cases, it can be lower than 35 percent. The first and second scans may be performed in any order, and they may be performed in succession without having the object move from the support table, or they may be performed with a sufficiently long span of time, such as on different days, to allow the object to be away from the support table for a period of time. The projection data may be stored in a computer-readable medium. This action may be performed in an interleaved manner, with a portion of the action being performed after each scan, or contemporaneously with each scan. Further preferred embodiments of this method may include generating a three-dimensional CT data set from these projections using a truncated reconstruction method, as described below in greater detail. Data of the first scan may be used to estimate the missing data of the second scan. The obscured regions of either or both of the first and second scans may be used to generate estimates of the scattered radiation (as described below in greater detail), and these estimates may be subtracted out of the projection data, or otherwise factored out, prior to the reconstruction procedure. Reconstruction Computer-Program Products. Related to the above inventions are a plurality of computer-program product inventions related to reconstructing three-dimensional CT data (e.g., voxels) from the two-dimensional projection data collected above. These products are described next. A first exemplary product is shown at 300 in FIG. 14. Product 300 comprises a computer-readable medium and a plurality of instruction sets embodied on the computer-readable medium, as shown in the figure. Instruction set #1 directs the data processor to acquire the projection data that was collected in the above-described inventions, such as by methods 200 and 220. In one embodiment, the instruction set may direct the data processor to receive the data, such as by reading it from a computer-readable medium. In another embodiment, product 300 may be loaded onto controller 160 and this instruction set may direct the data processor of controller 160 to instruct system 100 (or 100′) to obtain the projection data. Typically, product 300 only uses one of instruction sets 2A and 2B, and may only comprise one or the other. Instruction set #2A directs the data processor to read the values of the imaging window (e.g., X1, X2, Y1, and Y2) from the stored projection data. Instruction set #2B directs the data processor to infer the extents of the imaging window (e.g., X1, X2, Y1, and Y2) from the stored projection data. This may be done by detecting the step change in pixel value that occurs at the boundaries of imaging window, such as convolving one or more of the projections with the sum of two orthogonal spatial derivative operators, which essentially generate the sum of dF/dx+dF/dy, where F represents the pixel data, and thereafter least-squares fitting four lines to the convolved data. It may also be done by a histogram analysis of the data to identify the group of pixels within the imaging window by their high value, differentiating them from the pixels outside the window by their low value, and then fitting a rectangle to pixels found to be within the window. Instruction set #3 directs the data processor to identify truncated projection data from the projection data and the values of the imaging window, as found by instruction set #2A or #2B. Instruction set #3 may create arrays of the truncated data, and copy the pixel values within the imaging window to the new array for each projection. It may also merely set index ranges to the full projection data, to which further instructions may refer. As an option component of product 300, instruction set #4 directs the data processor to generate estimates of the scattered radiation from the projection data outside of the imaging window, and to generate corrected truncated projection data from the truncated projection data and the estimates. Exemplary instructions for this are described in a dedicated section below. Instruction set #5 directs the data processor to perform a truncated reconstruction with the truncated projection data, or the corrected truncated projection data, if available, to generate a set of three-dimensional CT data. These instructions may implement the methods described in U.S. Pat. Nos. 5,640,436 and 6,542,573, or similar methods found in the art. The particulars of the reconstruction are not essential to the invention of product 300. Instruction set #6 directs the data processor to store the generated three-dimensional CT data in a computer-readable medium. From the three-dimensional CT data, a number of crosssections of the target volume may be constructed. Product 300 may comprise additional instruction sets that receive input from an operator to select a crosssection for display, and that in turn display the requested crosssection. The particulars of such crosssection display instructions are not essential to the invention of product 300. Product 300 may be run by data processor 160 (shown in FIGS. 2A and 2B), or another data processor. A second general reconstruction product is illustrated by the exemplary produce 340 shown in FIG. 15. Product 340 comprises a computer-readable medium and a plurality of instruction sets embodied on the computer-readable medium, as shown in the figure. It is similar to product 300, but is intended to process the dual-scan data collected by method 240, described above. Instruction set #1 directs the data processor to acquire the projection data that was collected with method 240, or the like, from the appropriate computer-readable mediums. In one embodiment, the instruction set may direct the data processor to receive the data, such as by reading it from a computer-readable medium. In another embodiment, product 300 may be loaded onto controller 160 and this instruction set may direct the data processor of controller 160 to instruct system 100 (or 100′) to obtain the projection data. Instruction set #2A directs the data processor to read the values of the imaging window (e.g., X1, X2, Y1, and Y2) for each of the scans from the stored projection data. Instruction set #2B directs the data processor to infer the extents of the imaging window (e.g., X1, X2, Y1, and Y2) for each of the scans from the stored projection data. This may be done as described above for method 300, the actions of which are incorporated herein by reference. Typically, product 340 only uses one of instruction sets 2A and 2B, and may only comprise one or the other. Instruction set #3 directs the data processor to identify truncated projection data for both of the scans from the projection data and the values of the imaging window, as found by instruction set #2A or #2B. Instruction set #3 may create arrays of the truncated data, and copy the pixel values within the imaging window to the new array for each projection. It may merely set index ranges to the full projection data, to which further instructions may refer. As an option component of product 340, instruction set #4 directs the data processor to generate estimates of the scattered radiation from the projection data outside of the imaging window, and to generate corrected truncated projection data from the truncated projection data and the estimates. This is preferably done for both scans. Exemplary instructions for this are described in a dedicated section below. If the imaging window for the scan of the larger pixel area covers the entire pixel array, this step is omitted for the larger-area scan, or is modified to use estimates from the smaller-area scan. Instruction set #5 directs the data processor to perform a truncated reconstruction with the truncated projection data, or the corrected truncated projection data, if available, to generate a set of three-dimensional CT data. These instructions may implement the methods described in published PCT application WO-2005-104038 A1, or similar methods found in the art. The method essentially finds where each projection of the smaller-area scan matches the corresponding projection of the larger-area scan (which may be done by a two-dimensional auto-correlation of the original data or the scatter-corrected data), and then replaces the data of the larger-area scan in the matched area with the corresponding data of the smaller-area scan, in the matched area. The particulars of the reconstruction are not essential to the invention of product 340. Instruction set #6 directs the data processor to store the generated three-dimensional CT data in a computer-readable medium. From the three-dimensional CT data, a number of crosssections of the target volume may be constructed. Product 340 may comprise additional instruction sets that receive input from an operator to select a crosssection for display, and that in turn display the requested crosssection. The particulars of such crosssection display instructions are not essential to the invention of product 340. Product 340 may be run by data processor 160 (shown in FIGS. 2A and 2B), or another data processor. It may be appreciated that each of the above computer-program products performs a corresponding method, which may be separately recited herein as a set of independent and dependent method claims. Scatter-Estimation Methods and Computer-Program Products. FIG. 16 shows the pixel values of an axial line of pixels from Y1 to Ypix for some value of X that crosses through the imaging window. Image data and scattered radiation are present within the imaging window (the scattered radiation being much less compared to the case of a full-width imaging window), and scatter radiation is present at the extremes of the axial line (near Y=1 and Y=Ypix). At the edges of the imaging window, there are transition regions due to the penumbra of radiation source 110. As is know in the art, the source is not a perfect point, but has some width. This width interacts with the edges of fan blades 130 to create a tapering of the incident radiation, rather than a step change, and this tapering causes tapered regions of width Δp between the edges of the imaging window and the scatter radiation profiles at the extremes. The likely profile of the scattered radiation within the imaging window can be estimated by human eye as the dot-dashed line shown in the figure. A good estimate of the likely profile can be generated at the dashed straight line, which is constructed as a straight line from two pixel values just outside of the two penumbra regions, such as at (Y1−Δp) and (Y2+Δp). This is a simple linear interpolation form. More complex interpolation forms may be used, such as splines. Because the pixel data often has spurious noise, it is preferred to average the value of (Y1−Δp) with the corresponding values of adjacent axial lines, and to average the value of (Y2+Δp) with the corresponding values of adjacent axial lines, before constructing the interpolation. This will lessen the effects of spurious noise. This interpolation may be done for each axial line traversing the imaging window. While the above methods of estimating the scatter radiation have been done along the axial lines, it may be done along the trans-axial lines as well, particularly if the trans-axial width of the imaging window is narrower than the axial width of the imaging window. Once the estimates of the scatter radiation inside the imaging window are generated by such an interpolation, they may be subtracted directly from the corresponding pixel values in the imaging window to generate corrected projection data. However, because of possible spurious noise, it may be preferred to perform a truncated subtraction rather than a direct subtraction. The truncated subtraction is generated by forming the ratio between the scatter estimate for a pixel and the pixels value, limiting the maximum value of this ratio to a predetermined ceiling value a that represents a reasonable expected upper bound for scattering ratio, multiplying the limited ratio by the pixel's value, and thereafter subtracting the resulting multiplication from the pixel value. This may be mathematically expressed as PVc=PV−PVlimit(SE/PV, α), where PVc is the scatter-corrected pixel value, PV is the pixel value, SE is the scatter estimate for the pixel, and limit(,*) is the limit function. In view of the above discussion, an exemplary computer-program product 400 for scatter correction is provided in FIG. 17. Product 400 is suitable for stand-alone use or use with products 300 and 340 as instruction set #4. Product 400 comprises a computer-readable medium and a plurality of instruction sets embodied on the computer-readable medium, as shown in the figure. Instruction set #1 directs the data processor to acquire the projection data of a scan and the values of the imaging window (e.g., X1, X2, Y1, and Y2). In one embodiment, the instruction set may direct the data processor to receive the data, such as by reading it from a computer-readable medium. In another embodiment, product 400 may be loaded onto controller 160 and this instruction set may direct the data processor of controller 160 to instruct system 100 (or 100′) to obtain the projection data. Instruction set #2 directs the data processor to generate one or more interpolated profiles of the estimated scattered radiation across the imaging window suitable for each projection of the scan. Instruction set #2 preferably includes averaging pixel values outside of the imaging window, and generating the interpolations from the averaged values. Product 400 includes instructions embodied on the computer-readable medium that directs the data processor to store the estimates of the scattered radiation on a computer-readable memory. Instruction set #3 directs the data processor to generate a set of corrected projection data for each projection from the projection data itself and the interpolated profile(s) of the estimated scattered radiation across the imaging window for the projection. This may be generated as a direct subtraction of the estimated scatter profile from the pixel values, or as the truncated subtraction of the estimated scatter profile from the pixel values, as described above. Instruction set #4 directs the data processor to store the corrected projection data for each projection in a computer-readable medium. It may be appreciated that the above computer-program products perform corresponding methods, which may be separately recited herein as sets of independent and dependent method claims. For projection data collected from method 240 for the large-area scan, if the imaging window covers the entire area of the large area scan, then the interpolation profiles of estimated scattered radiation generated for each projection of the small-area scan may be applied to the corresponding projection of the large area scan, with the profiles being extrapolated to the regions outside of the imaging window, and optionally scaled by a factor greater than 1 to account for the additional radiation received by the object during the large area compared to the small area scan. (The additional radiation received by the object cases more scattered radiation in the large area scan than compared to the small area scan.) The instruction sets of the above-described computer-program products may be combined together, either in whole or various sub-combinations, to provide additional computer-program products. The actions of the methods performed by the instruction sets may be similarly combined to provide additional methods. Additional Collimator Structures. In addition to fan blades, the present inventions may be practiced with various collimator structures. An exemplary collimator structure 500 is shown in FIG. 18. It comprises a plate of radiation attenuation material, with the properties described above for fan blades 130 and 140, a central aperture 510 through the plate to allow radiation to pass without attenuation, and a plurality of slits 520 disposed along the axial and trans-axial dimensions, crossing at the center of aperture 510. Collimator 500 may replace fan blades 130 and 140 in systems 100 and 100′, and may be moved in the axial and trans-axial directions by linear motor servos and the like. Collimator 500 produces a circular or oval-shaped image window on imaging device 120, and it may also be moved along the projection axis by another linear motor servo to vary the diameter of the image window. Slits 520 also allow radiation to pass through the plate without attenuation, and generate projection slices of the object which may be found and used by truncation reconstruction programs to better estimate the missing projection data. Slits 520 do not appreciably increase the scatter radiation. Slits 520 may be incorporated into fan blades 130 and 140. Any recitation of “a”, “an”, and “the” is intended to mean one or more unless specifically indicated to the contrary. As used herein, computer-readable medium includes, but is not limited to, volatile memory, such as a data memory of a data processor, non-volatile memory (such as EPROMs, EEPROMs, “jump drives”), magnetic disk drive storage (including fixed media and removable media), floppy disks, optical discs (such as CD-ROM discs and writable DVD discs), magnetic tape, optical tape, magnetic drums, optical drums, holograms, and any other tangible medium to which data may be written, and from which data may be read, at the request of a computer, microprocessor, data processor, and the like. The pixel arrays used here preferably have X- and Y-dimensions of at least 100 pixels in each dimension, and more preferably at least 400 pixels in each dimension, and most preferably at least 700 pixels in each dimension. The terms and expressions which have been employed herein are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding equivalents of the features shown and described, it being recognized that various modifications are possible within the scope of the invention claimed. Moreover, one or more features of one or more embodiments of the invention may be combined with one or more features of other embodiments of the invention without departing from the scope of the invention. While the present invention has been particularly described with respect to the illustrated embodiments, it will be appreciated that various alterations, modifications, adaptations, and equivalent arrangements may be made based on the present disclosure, and are intended to be within the scope of the invention and the appended claims.
	summary
039649660	abstract	Molten fuel produced in a core overheating accident is caught by a molten core retention assembly consisting of a horizontal baffle plate having a plurality of openings therein, heat exchange tubes having flow holes near the top thereof mounted in the openings, and a cylindrical, imperforate baffle attached to the plate and surrounding the tubes. The baffle assembly is supported from the core support plate of the reactor by a plurality of hanger rods which are welded to radial beams passing under the baffle plate and intermittently welded thereto. Preferably the upper end of the cylindrical baffle terminates in an outwardly facing lip to which are welded a plurality of bearings having slots therein adapted to accept the hanger rods.
047568763	description	The drawing shows the containment 1 of the modular device which consists of walls 2 of great thickness made of lead, covered on ther inner faces with a steel sheet 3. The containment 1 comprises a side wall 2a and a bottom 2b which are connected to one another so as to form a shaft of vertical axis ZZ', the bottom of which is closed in a leak-proof manner by means of the sheets 3 covering the walls 2a and 2b. Reinforced angle pieces 5 are fastened to the edges of the bottom 2b, to constitute the supports of the modular ultrafiltration device. These angle pieces are perforated with holes making it possible to fasten the device on a supporting surface 6 by means of screws. The orifice located in the upper part of the containment 1 is closed by means of a cover 7. Inside the containment 1, the ultrafilter 15 is retained by means of an assembly of beams 50 arranged radially and fastened on the one hand to the outer wall of the casing 8 of the ultrafilter and on the other hand to the steel sheet 3 covering the inside of the containment 1; the dimensions of these beams make it possible to absorb forces, such as those generated by a seismic shock or in the event of an accident of any kind. The casing 8, which is symmetrical in terms of revolution and which is arranged in the containment 1 with its axis coinciding with the axis ZZ', comprises a cylindrical central part, integral with a connecting flange 9 of great thickness, and a rounded bottom. The casing 8 contains an ultrafiltration assembly 10 which can be introduced into this containment 8 or removed via its upper orifice 8a. Three connection pieces pass through the wall of the casing 8: an inlet connection piece 12 for water to be purified and a concentrateoutlet connection piece 14, both in the upper part of the casing, and a filtrate-outlet connection piece 16 in the lower part of the casing 8. The connection pieces 12 and 16 pass through the side wall 2a of the containment 1 in a leak-proof manner by means of a metal membrane 51 welded, on the one hand, to the inner wall 3 of the containment and, on the other hand, to the corresponding connection piece, and on the outside of the containment 1 are integral with connecting flanges 13 and 17, respectively. There will now be a brief description of the ultrafiltration assembly 10 and its arrangement inside the casing 8, the ultrafilter 15 consisting of the casing 8, its connection pieces and the elements arranged inside the casing 8 being of a new type described in a patent application filed on the same day as the present application. The ultrafiltration assembly 10 consists of a cylindrical casing 11 with a rounded bottom, inside which is placed the ultrafiltration wall consisting of an assembly of vertical tubes 18, the ends of which are fastened on the inside of two tube plates 19 and 20 respectively. The upper tube plate 20 is machined on its periphery to form a groove which receives an O-ring gasket 52 interacting with a gasket bearing surface 53 attached to the inner surface of the casing 8. Centering pieces 54 integral with the inner surfaces of the casing 8 ensure that the casing 11 is retained transversely. The rounded bottom of the casing 11 bears on the bottom of the casing 8 by means of a spring 55. Arranged above the plate 20 is a partitioning 21 which makes it possible to delimit several compartments in the inner volume of the casing 8 above the plate 20. In the same way, a partitioning 22 makes it possible to delimit several compartments in the part of the casing 11 located underneath the tube plate 19. The ultrafilter 15 operates as follows: The water to be purified is introduced into the casing 8 via the connection piece 12, inside one of the compartments delimited by the partitioning 21. The water to be purified penetrates into the ultrafiltration tubes and then circulates inside these tubes 18 in one direction and then the other as a result of the relative arrangement of the partitionings 21 and 22. The liquid circulating in the tubes 18 constitutes the concentrate, the impurity content of which increases, and filtrate consisting of pure water passes through the walls of the tubes and enters the inner volume of the casing 11 between the tube plates 19 and 20. A partitioning (not shown) also allows the filtrate to circulate in this space of the ultrafiltration assembly. The last compartment in the circulation of the filtrate communicates via an orifice passing through the casing 11 with the space provided between the casings 8 and 11. The filtrate is discharged through the connection piece 16 which communicates with the space. The last compartment arranged in the circulation of the concentrate and above the plate 20 communicates with the concentrate-outlet connection piece 14. A pump 25 for circulating the water to be purified and the concentrate is fastened to the removal cover 7 of the containment 1. This pump incorporates a connecting flange 26 matching the flange 9 of the ultrafilter 15. the flanges 9 and 26 have holes in matching positions for the passage of bolts or fastening screws. A gasket 27 is inserted between the two flanges during assembly, with the result that the pump 25 and its flange 26 ensure the leak-proof closure of the upper part of the casing 8. The pumping and circulation of the concentrate are carried out by means of the pump 25, of which the necessary junctions with the corresponding compartments delimited by the partitioning 21 are provided. Holes 29 pass through the cover 7 in line with the fastening screws of the flanges 9 and 26, to allow these flanges to be fitted and removed. The pump 25 is cooled by a cooling fluid penetrating into the pump housing via a pipeline 30. Lifting rings 31 and 32 respectively are fastened to the containment 1 and to the pump 25, thus making it possible either to transport the molded assembly by means of the rings 31 or to transport the pump 25 by means of the rings 32 and gain access to the tube bundle. A cylindrical heat exchanger 32 with a rounded bottom, making it possible to cool the concentrate, is mounted inside the containment 1. The concentrate-outlet connection piece 14 penetrates in a leak-proof manner inside the casing of the heat exchanger 32, where it is connected to an exchange tube, the other end of which is connected to a concentrate-discharge connection piece 35. The connection piece 35 passes through the containment 1 so as to be connected on the outside of this containment 1 to a connecting flange 36. Cooling fluid is introduced into the casing of the exchanger 32 via a connection piece 37 and is recovered via a connection piece 39, and the connection pieces 37 and 39, because of welded sealing membranes 51, pass in a leak-proof manner through the side wall 2a of the containment 1, to be connected outside this containment to connecting flanges 38 and 40, respectively. A heat-insulating material in divided form 41 fills the free volume of the containment 1 outside the elements located within this containment 1. The modular ultrafiltration device just described can be mounted very easily inside the containment shell of a nuclear reactor, for example in order to be arranged on an ultrafiltration loop taken off from an auxiliary primary-fluid treatment circuit, to constitute an ultrafiltration circuit of a new structure, such as that described in a patent application filed on the same day as the present application. All that is necessary, in fact, is to place the modular ultrafiltration device at the desired location by using a lifting means attached to the rings 31. The module is subsequently secured in place by means of its supports 5. The connection pieces are then connected up, by means of the corresponding connecting flanges, to the corresponding pipes provided for this purpose. The module, assembled in the way shown in the drawing, incorporates all the necessary active elements of the ultrafiltration loop and can be connected to the auxiliary primary-fluid treatment circuit purely by means of passive elements. It is quite clear that the modular device can be removed very simply and very quickly, and the module as a whole provides biological protection because of the very thick lead walls 2. Furthermore, the modular device in itself provides good thermal insulation for its elements, in which the primary water circulates, by means of the material in divided form 41. On the other hand, one of the essential advantages of the modular device according to the invention is that it makes it possible to separate and extract the ultrafiltration assembly easily, in order to service it, repair it or replace its tubular ultrafiltration wall. All that is necessary for this purpose, in fact, is to separate the flanges 9 and 26 from outside the containment 1 and then lift the cover 7 and the flange 26 by means of the ring 32 of the pump 25, to gain access to the inner part of the casing 8 containing the partitioning 21 and the ultrafiltration assembly 10. The filter can be refitted very easily and very quickly by means of operations carried in reverse order to the removal operations, for example after the ultrafiltration assembly 10 has been replaced. The invention is not limited to the embodiment which has been described. The thick-walled containment can be made in a different form, and the components constituting the module can be placed in different respective arrangements. For example, the arrangement of the ultrafilter 15 can be completely reversed, the liquid to be purified entering in its lower part and the filtrate being discharged in its upper part. Finally, the modular ultrafiltration device according to the invention can be used in any nuclear reactor, the cooling liquid of which is at a high temperature and a high pressure.
050531913	description	DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 shows a single fuel assembly 10 having a lower end fitting 12 resting on a lower core support plate 14, an upper end fitting 16 vertically spaced from the lower end fitting 12, and a plurality of thimble tubes 18 rigidly connected to the end fittings. A plurality of vertically spaced apart grids 20 are rigidly connected to the thimble tubes 18, and define an egg crate-type structure for individually supporting a plurality of nuclear fuel rods 22, in a manner well known in the art. On a periodic basis, for example annually, the nuclear reactor is opened, the upper core support plate 24 removed, depleted fuel assemblies 10 are removed and replaced, and the remaining assemblies are rearranged. The upper core plate 24 is then lowered onto the upper end fittings 16 so as to contact and load the cantilever spring packs 28 which define the vertically upper extent of the fuel assembly. FIGS. 2 and 3 show the upper end fitting 16 and associated cantilever spring packs 28 of the prior art, in greater detail. For purposes of the present invention, it should be appreciated that one spring pack 28 is attached along each upper rim 30a, b, c and d of the end fitting 16. Each spring pack 28 has a primary spring member 32 Which is preferably a bent, unitary, substantially flat bar of varying thickness. The primary spring 32 has a straight, long leg portion 34 with one end 36 attached in a known manner to the corner bracket 38 or fixture of the end fitting, and a second end 40 defining the juncture at which the spring member begins to form the arcuate transition portion 42 which turns in the direction away from the upper core plate. A straight, short leg portion 44 typically extends vertically downward from the transition portion and has a free end 46 spaced from a stop 48 formed in the end fitting. At the juncture 40 of the second end of the long leg with the transition portion, the vertically highest elevation of the spring member 32 and of the fuel assembly is established. This serves in the prior art as the only loading point, and in the present invention as the primary loading point, against the upper core plate. As shown in FIG. 3(b), the normal operating condition of the reactor provides a space 50 between the upper core plate 24 and the rigid frame 52 of the upper end fitting 16. During some transient conditions, as shown in FIG. 3(c), the spring can become excessively loaded so that it deforms plastically. The rigid stop surface 48 is provided in order to preclude contact between the upper core plate 24 and the upper end fitting frame 52. Such contact would directly transmit unbiased loads to the thimbles 18 shown in FIG. 1, and has the potential for damaging or distorting the thimbles or the grids 20 in a manner that could require the repair or replacement of the assembly 10 prior to the resumption of normal reactor operation. In order to increase the stiffness in the prior art springs 32, one or more auxiliary springs 54 are provided, each of which has a first end 56 secured to the upper end fitting adjacent to the first end 36 of the primary spring 32, preferably in stacked fashion under the same corner bracket 38, and a free end 58 which extends to the vicinity of the juncture of the transition portion with the short leg portion 44 of the primary spring. At the second ends 58, the auxiliary springs have openings 60 through which the short legs pass, but the walls define openings 60 sufficiently narrow so that the walls engage downwardly facing shoulders 62 on the transition portion 42. In this manner, the secondary springs 54 provide a cantilevered, upward bias on the primary cantilevered spring 32. It should be appreciated, however, that as shown in FIG. 3(c), the primary spring yields beyond its elastic limit during accident conditions, even before the upper core plate 24 contacts the upper end fitting 16. Moreover, the contact of the free end 46 of the short leg with the stop 48 immediately increases the rigidity of the primary spring 32, so that although the core plate does not contact the upper end fitting, the shape of the primary spring is such that the severe loading while the free end 46 is in contact with the stop 48, further permanently deforms the spring. This deformation is great enough in the prior art to degrade the performance of the spring upon return to normal operating conditions. In accordance with the present invention, as shown in FIGS. 4(a)-(c), a thickening or projection 64 is formed on the upper surface of the long leg 66 of the primary spring 68, for the purpose of changing the fuel assembly holddown spring rate upon the occurrence of a known or predetermined deflection of the primary spring resulting from the movement of the core plate 24 and end fitting 16 relatively toward each other. Viewed from another aspect, the conditions under which the stiffening due to the projection occurs, directly correlates with the displacement of the primary loading point 70 downwardly toward the fuel rods. As shown in FIG. 4(c), the contact 72 of the upper core plate with the projection 64, effectively shortens the cantilever of the primary spring 68 and thereby increases the spring rate. The increased stiffness maintains an adequate spacing between the upper core plate and the frame 52 of the upper end fitting, such that the free end 74 of the short leg 76 does not bear against the stop 48 under loads which would result in the prior art condition shown in FIG. 3(c). The exact shape and placement of the projection 64 is to be determined by the ordinarily skilled practitioner in accordance with the particular needs of the reactor system into which the fuel assemblies will be placed. In general, however, the projection is in the form of a large dimple that is closer to the transition portion 70 of the primary spring, than it is to the rigid attachment to the bracket 38. As shown in FIG. 4(a), the vertical peak 72 of the dimple 64, is at approximately the same elevation as the shoulders 78 at the juncture between the transition portion 70 and the short leg 76 of the primary spring, when the spring is in the unloaded condition. The vertical peak of the dimple is at a lower elevation than the primary loading point 80 at the second end of the long leg. In general, the difference in elevation between the primary loading point 80 and the dimple peak 72 in the unloaded condition, indicated by d.sub.1 in FIG. 4(a), is less than the distance between the free end 74 of the short leg and the stop 48 in the unloaded condition, as shown at d.sub.2 in FIG. 4(a). Preferably, the distance d.sub.1 will lie in the range 0.25 d.sub.2 .ltoreq.d1.ltoreq.0.50 d.sub.2. As shown in FIG. 4(b), in the normally loaded condition, the peak 72 of the dimple remains below the elevation of the primary loading point 80, and above the elevation of the end fitting frame 52. Although the invention as shown in the drawings provides the projection 64 in the form of a dimple, it should be appreciated that, more generally, the dimple is a special form of the thickening of the beam 66 at a point along the long leg as one follows the profile of the long leg from the primary loading point 80 toward the spring attachment point. This variation in the thickness of the long leg, allows the change of loading points, thereby decreasing the length of the cantilever beam and increasing the spring stiffness. The present invention accommodates significantly higher spring loads under a variety of accident and start-up conditions. This improved capability is especially advantageous to the plant operators during certain reactor start-up conditions, whereby the operators may, with the benefit of the present invention, operate within a wider window, and thus achieve full power more quickly.
	description	The present application claims priority from Japanese Patent application serial no. 2008-001077, filed on Jan. 8, 2008, the content of which is hereby incorporated by reference into this application. The present invention relates to jet pump and reactor and more particularly, to a jet pump and a nuclear reactor suitable for application in a boiling water reactor. A conventional boiling water reactor (BWR) has a jet pump installed in its reactor pressure vessel. The jet pump has a nozzle, a bell mouth, a throat, and a diffuser. A recirculation pipe is connected to the reactor pressure vessel. Cooling water pressurized by operation of a recirculation pump provided on the recirculation pipe, passes through the recirculation pipe and is ejected from the nozzle into the jet pump as a driving flow. The nozzle increases the speed of the driving flow. The ejected driving flow causes the cooling water present around the nozzle to flow into the throat as a suction flow. The cooling water discharged from the diffuser is supplied to a core through a lower plenum (for example, see U.S. Pat. No. 3,625,820). A jet pump disclosed in Japanese Patent Laid-open No. 2002-89499 has a suction pipe for sucking a conveying object (rainwater, wastewater flowed into a grit pound, solid matter, etc.) and an annular member surrounding the suction pipe. In addition, this jet pump forms a high-pressure water feed chamber between the suction pipe and the annular member, provided around the suction pipe. A plurality of water injection openings opened to the high-pressure water feed chamber are disposed around the suction pipe. High-pressure water supplied into the high-pressure water feed chamber is jetted from those injection openings to suck the conveying object into the suction pipe. The jet pump disclosed in FIG. 3 of Japanese Patent Laid-open No. 2001-90700 has a venturi pipe and a nozzle for ejecting a driving flow to the upper course of the venturi pipe. This nozzle has an inner cylinder and an outer cylinder surrounding the inner cylinder. A driving flow passage formed between the inner cylinder and the outer cylinder is an annular passage for the driving flow, the cross section of which passage gradually diminishes toward the discharging side of the driving flow. The driving flow supplied to the driving flow passage is ejected from one end of the passage (a discharge outlet) into the venturi pipe. Washing water present around the nozzle is sucked into the venturi pipe due to the driving flow ejected from the nozzle. To be more precise, this washing water flows into the venturi pipe through each of a first coolant suction passage formed between the nozzle and the venturi pipe and a second coolant suction passage formed inside the inner cylinder. The driving flow in a cylindrical form is ejected from the nozzle. The cross sections of the driving flow in a cylindrical form look like continuous rings. Performance of a jet pump can be indicated by the M ratio, N ratio and efficiency as shown below. M ratio is the ratio of a flow rate Qs of the suction flow (cooling water) flowed into a throat portion, to a flow rate Qn of the driving flow (recirculating water) at a nozzle portion, represented as in an equation (1).M ratio=Qs/Qn (1) N ratio is the total pressure ratio of the suction flow to the driving flow, represented as in an equation (2).N ratio=(Pd−Ps)/(Pn−Pd) (2) Here, Pd is the total pressure of a diffuser portion, Ps is the total pressure of the throat portion, and Pn is the total pressure of the nozzle portion. Efficiency η is the ratio of energy of the suction flow to the driving flow, represented as a product of the M ratio and the N ratio.η=M ratio×N ratio (3) It is preferable for a jet pump to have a larger M ratio, N ratio and efficiency η. If the flow rate of the cooling water discharged from the jet pump could be efficiently increased using a recirculation pump of small capacity, the recirculation system can be downsized and installation space for the recirculation system can be reduced. For example, when a power uprate in an existing nuclear reactor (BWR, for example) is to be implemented, the reactor power can be increased by increasing the core flow to enhance the cooling capability of the core. In addition, since expanding the control range of the core flow rate increases the range of void fraction change in the core, the economical efficiency of fuel can be improved. In order to increase the core flow rate, the recirculation pump, the feed water pump, and the jet pump may be modified. The inventors have found out that modification of the jet pump was more effective than reconstruction or replacement of large equipment such as the recirculation pump and the feed water pump, for the reconstruction of the existing reactor for the power uprate. Since performance of the jet pump heavily depends on the shape of the mixing part for mixing the driving flow and the suction flow, the performance may be improved by modifying the nozzle for ejecting the driving flow. The jet pump disclosed in Japanese Patent Laid-open No. 2002-89499, which has the suction pipe for sucking a conveying object, and the annular member surrounding the suction pipe to supply a driving flow inside, cannot be used as a jet pump of the nuclear reactor to supply coolant to the core. If the jet pump disclosed in the patent document is installed in a downcomer, which is an open area inside the reactor pressure vessel, pressure loss at the suction portion will be too large to increase the M ratio. If the diameter of the suction pipe is made larger to reduce the pressure loss at the suction portion and also to increase the M ratio, the high-pressure water feed chamber that is the annular portion, will be large, causing the jet pump to be uninstallable in the small downcomer area above a set of two jet pumps in a current BWR. The jet pump disclosed in FIG. 3 of Japanese Patent Laid-open No. 2001-90700 flows a suction flow present around the nozzle into the venturi pipe through each of the first coolant suction passage and the second coolant suction passage by ejecting a driving flow from the nozzle. By using the nozzle disclosed in Japanese Patent Laid-open No. 2001-90700 in the jet pump disclosed in U.S. Pat. No. 3,625,820, the efficiency of the jet pump can be increased. However, in the jet pump disclosed in FIG. 3 of Japanese Patent Laid-open No. 2001-90700, the driving flow is supplied to the driving flow passage formed between the inner cylinder and the outer cylinder, from the side at a right angle through a driving flow feeding pipe. Because of this, the driving flow flowing into the driving flow passage hits the inner cylinder from the side and turns downward at a right angle, causing great pressure loss and applies large forces to the connection part between the nozzle and the driving flow feeding pipe connected to the nozzle. The connection part between the nozzle and the driving flow feeding pipe needs to be strengthened. In addition, a jet pump disposed in the reactor pressure vessel of a BWR has an inverted U-shaped elbow pipe, a nozzle, and a throat portion joined as a single detachable unit. A raiser pipe connected to the elbow pipe is fixed to a core shroud surrounding the core and disposed in the reactor pressure vessel. In order to install the nozzle having the inner cylinder and the outer cylinder, the raiser pipe and a nozzle fixture need to be modified. To increase the degree of the power uprate of the reactor, further improvement in the efficiency of the jet pump is expected. An object of the present invention is to provide a jet pump and a nuclear reactor which can further increase efficiency of the jet pump. A feature of the present invention for achieving the above object is that a nozzle apparatus having a header portion including, inside, a first pipe member forming a suction fluid passage for introducing suction fluid and the header portion surrounding the first pipe member, for introducing driving fluid, and a nozzle portion connected to the header portion, surrounding the first pipe member and forming an annular ejection outlet for ejecting the driving fluid; and a second pipe member having one end connected to the nozzle apparatus, for introducing the driving fluid to the header portion are comprised, wherein the first pipe member is disposed through the one end inside a driving fluid passage formed in the second pipe member, and forms an opening portion of the suction fluid passage opened to the outside of the second pipe member; and the driving fluid passage is formed so that the driving fluid flowing toward the one end hits the first pipe member diagonally to the axial direction of the first pipe member. Since the driving fluid passage formed inside the second pipe member is formed so that the driving fluid flowing toward the one end hits the first pipe member diagonally to the axial direction of the first pipe member, pressure loss inside the driving fluid passage is decreased. Since the speed of the driving fluid ejected from the annular ejection outlet of the nozzle portion becomes faster, the flow rate of the suction fluid sucked inside the jet pump body is increased. From above, efficiency of the jet pump is improved. The above object can also be achieved by a feature that a nozzle apparatus having aheader portion including, inside, a first pipe member forming a suction fluid passage for introducing suction fluid and the header portion surrounding the first pipe member, for introducing driving fluid, and a nozzle portion connected to the header portion, surrounding the first pipe member and forming an annular ejection outlet for ejecting the driving fluid; and an inverted U-shaped second pipe member having one end connected to the nozzle apparatus, for introducing the driving fluid to the header portion are comprised, wherein the first pipe member extending to the axial direction of the nozzle apparatus is disposed through the one end inside a driving fluid passage formed in the second pipe member, and forms an opening portion of the suction fluid passage opened to the outside of the second pipe member; and a fixing position of the first pipe member to the second pipe member is disposed lower than the top point of the outer surface of the second pipe member. According to the present invention, efficiency of the jet pump can be further increased. Various embodiments of the present invention are described below using figures. A jet pump according to first embodiment is described the first embodiment which is a preferred embodiment of the present invention below. Before the structure of the jet pump in the present embodiment is explained, a general structure of a boiling water reactor (BWR) is described below using FIGS. 3 and 4. A boiling water reactor (BWR) 1 has a reactor pressure vessel (hereinafter, referred to as a RPV) 2 and a core 3 disposed in the RPV 2. A plurality of fuel assemblies (not shown) are loaded in the core 3. A core shroud 4 disposed in the RPV 2 surrounds the core 3. A separator 5 and a dryer 6 are disposed above the core 3 in the RPV 2. A plurality of jet pumps 7 are disposed in a downcomer 31 which is an annular passage formed between the RPV 2 and the core shroud 4. The RPV 2 is provided with a recirculation system. This recirculation system has a recirculation pipe 32 and a recirculation pump 33. The recirculation pipe 32 is provided with the recirculation pump 33. One end of the recirculation pipe 32 is connected to the RPV 2, connecting with the downcomer 31. The other end of recirculation pipe 32 reaches in the RPV 2 and connects to a raiser pipe 34 (see FIG. 4) disposed in the downcomer 31. A feed water pipe 36 and a main steam pipe 35 are connected to the RPV 2. The jet pump 7 has a nozzle apparatus 8, an inverted U-shaped elbow pipe (a second pipe member) 19, a bell mouth 24, a throat 25 and a diffuser 26. The diffuser 26 is disposed to a dividing member installed to the core shroud 4. The throat 25 is joined to an upper end portion of the diffuser 26 by a joint 27. The bell mouth 24 is installed on the upper end of the throat 25. The nozzle apparatus 8 is disposed above the bell mouth 24, and is fixed to the bell mouth 24 with a plurality of support plates 37. An outside cooling water suction passage 38 is formed between the nozzle apparatus 8 and the bell mouth 24. One end of the elbow pipe 19 is fixed to the upper end of the nozzle apparatus 8. Two jet pumps 7 are disposed on both sides of the single raiser pipe 34. Each nozzle apparatus 8 of the jet pumps 7 is connected to the single raiser pipe 34 through the individual elbow pipe 19. Cooling water (suction fluid, coolant) present in the upper part in the RPV 2 is mixed with feed water supplied to the RPV 2 from the feed water pipe 36 and goes down in the downcomer 31. This cooling water flows into the recirculation pipe 32 by operation of the recirculation pump 33, and pressurized by the recirculation pump 33. This pressurized cooling water is called a driving flow (driving fluid) for convenience. This driving flow flows into the elbow pipe 19 of the jet pump 7 through the recirculation pipe 32 and the raiser pipe 34, and after the flow direction is changed 1800 by the elbow pipe 19, ejects from the nozzle apparatus 8. Cooling water present around the nozzle apparatus 8 is sucked into the bell mouth 24 through the outside cooling water suction passage 38 by the ejection of the driving flow, and further sucked into the throat 25. This cooling water, with the driving flow, goes down in the throat 25 and the diffuser 26, and is discharged from the diffuser 26. The discharged cooling water (including the driving flow) is supplied to the core 3 via a lower plenum 39. The cooling water is heated when passing the core 3, and becomes a two-phase flow including water and steam. The separator 5 separates the steam and the water discharged from the core 3. Moisture in the separated steam is further eliminated by the dryer 6, and the steam is discharged to the main steam pipe 35. This steam is introduced to a steam turbine (not shown) and turns the steam turbine. The steam discharged from the steam turbine becomes water through condensation in a condenser (not shown). This water is supplied into the RPV 2 through the feed water pipe 36 as feed water. The water separated by the separator 5 and the dryer 6 goes down the downcomer 31. The jet pump 7 effectively sucks the cooling water around the nozzle apparatus 8 by using the driving force of the driving flow discharged from the recirculation pump 33, and increases the flow rate of the cooling water discharged from the jet pump 7 more than the flow rate of the driving flow. The effective use of the kinetic energy of the driving flow generated by the recirculation pump 33 increases the rate of the cooling water discharged from the jet pump 7. The flow speed of the driving flow at the outlet of the nozzle apparatus 8 is increased to increase the kinetic energy of the driving flow, and at the same time, the passage area of the throat 25 is made smaller than that of the bell mouth 24 to increase the speed of the cooling water, so that static pressure can be reduced. From these, the cooling water can be sucked in the throat 25, and a required core flow rate can be obtained with little power. In the jet pump 7, in order to increase the M ratio and the N ratio and to further improve the efficiency η, it is important to minimize pressure loss and to optimize suction power induced by the driving flow. Thus, in the jet pump 7 in the present embodiment, an inner cooling water suction passage 17 which runs through the nozzle apparatus 8 in the axial direction, is formed inside the nozzle apparatus 8, forming an opening portion 18 connecting with the downcomer 31, at the upper end. In addition, in the jet pump 7, the inner cooling water suction passage 17 extends upward inside the elbow pipe 19, and the opening portion 18 is formed on the outer surface of the elbow pipe 19 at a lower position than a top point TP of the elbow pipe 19. A detailed structure of vicinity of the nozzle apparatus 8 in the jet pump 7 according to the present embodiment is explained using FIGS. 1 and 2. The jet pump 7, as described above, has the nozzle apparatus 8, the elbow pipe (the second pipe member) 19, the bell mouth 24, the throat 25 and the diffuser 26. The bell mouth 24, the throat 25 and the diffuser 26 are referred to as a jet pump body. The throat 25 has the smallest passage cross section in the jet pump body. The passage cross section of the bell mouth 24 expands upward from the connection portion with the throat 25. The passage cross section of the diffuser 26 gradually expands downward from the connection portion with the throat 25. The nozzle apparatus 8, as shown in FIG. 1, has a nozzle portion 9 and a nozzle header portion 13. The nozzle header portion 13 has an outer cylinder member 14 and an inner cylinder member 15 disposed inside the outer cylinder member 14. An annular header portion 16 is formed between the outer cylinder member 14 and the inner cylinder member 15, which are concentrically disposed. The nozzle portion 9 is disposed below the nozzle header portion 13 and fixed to the lower end portion of the nozzle header portion 13. The nozzle portion 9 has an outer cylinder member 10, an inner cylinder member 11, an outer funnel portion 40, and an inner funnel portion 41. The outer cylinder member 10 surrounds the inner cylinder member 11, and the outer cylinder member 10 and the inner cylinder member 11 are concentrically disposed. The outer funnel portion 40 surrounds the inner funnel portion 41, and the outer funnel portion 40 and the inner funnel portion 41 are concentrically disposed. Each cross section of the outer funnel portion 40 and the inner funnel portion 41 diminishes downward. The outer funnel portion 40 is fixed to the upper end of the outer cylinder member 10, and the inner funnel portion 41 is fixed to the upper end of the inner cylinder member 11. The outer funnel portion 40 is disposed to the lower end of the outer cylinder member 14. The inner funnel portion 41 is disposed to the lower end of the inner cylinder member 15. An annular ejection outlet 12 is formed between the outer cylinder member 10 and the inner cylinder member 11. An outlet end 21 of the elbow pipe 19 is fixed to the nozzle header portion 13, that is, the upper end of the outer cylinder member 14. An inlet end 20 of the elbow pipe 19 is disposed to the upper end of the raiser pipe 34. The elbow pipe 19 is provided with a fixing pedestal 29 having a through-hole 42. The elbow pipe 19 is detachably coupled with the raiser pipe 34 by a fixture 30. The center of the outlet end 21 of the elbow pipe 19 matches the axis of the nozzle header portion 13, or the outer cylinder member 14. The nozzle portion 9, the nozzle header portion 13, and the elbow pipe 19 are joined into a single unit by welding. The inner cylinder member 15 is inserted in the elbow pipe 19 from the outlet end 21 and extends upward. An opening portion 18 located at an upper end portion of the inner cylinder member 15 is formed on the outer surface of the elbow pipe 19 and connecting with the downcomer 31. The upper end of the inner cylinder member 15 is welded to the elbow pipe 19. A joint portion (fixed portion) 23 being at the highest point in the joint portion (fixed portion) of the inner cylinder member 15 to the elbow pipe 19 is disposed lower than the top point TP which is the highest point on the outer surface of the elbow pipe 19. A flow-adjusting plate (flow-adjusting member) 22 having the same curvature as the elbow pipe 19 is installed inside the elbow pipe 19, and disposed from the inlet end 20 of the elbow pipe 19 toward the inner cylinder member 15 along the axis of the elbow pipe 19. The flow-adjusting plate 22 is disposed to the upper course of the inner cylinder member 15. An upper passage 44 and a lower passage 45 are formed in the elbow pipe 19 by the installation of the flow-adjusting plate 22, which passages are separated into the top and bottom. Since the joint portion 23 is located lower than the top point TP, the upper passage 44 and the lower passage 45 in the elbow pipe 19 toward the outlet end 21 are formed diagonal to the axis of the inner cylinder member 15. In other words, the upper passage 44 and the lower passage 45 are formed so that the driving flow in the passages flows toward the outlet end 21, hitting the inner cylinder member 15 diagonally to the axial direction of the inner cylinder member 15. The inner cooling water suction passage 17 connecting with the downcomer 31 through the opening portion 18 is formed inside of the inner cylinder member 15, the inner funnel portion 41 and the inner cylinder member 11 all joined together. The joined inner cylinder member 15, the inner funnel portion 41 and the inner cylinder member 11 are first pipe members. The passage cross section of the inner cooling water suction passage 17 gradually diminishes downward in the inner funnel portion 41, and the lower end of the inner cooling water suction passage 17 opens toward the bell mouth 24. An annular passage 43 formed between the outer funnel portion 40 and the inner funnel portion 41 connects between the annular header portion 16 and the annular ejection outlet 12, and the passage cross section of the annular passage 43 gradually diminishes downward. A driving flow pressurized by the recirculation pump 33, that reaches the raiser pipe 34 is introduced into the annular header portion 16 through the elbow pipe 19. Since the flow-adjusting plate 22 is disposed in the elbow pipe 19, pressure loss in the elbow pipe 19 is reduced. In the elbow pipe 19, a part of the driving flow inside each of the upper passage 44 and the lower passage 45 flows toward the outlet end 21 hitting the outer surface of the inner cylinder member 15 diagonally to the axial direction of the first pipe member (especially the inner cylinder member 15). The driving flow introduced into the annular header portion 16 passes through the annular passage 43 and is ejected at a high speed toward the bell mouth 24 from the annular ejection outlet 12. The cross section of the driving flow ejected from the annular ejection outlet 12 is annular. Supplying the driving flow into the throat 25 at high speed reduces static pressure in the throat 25, and cooling water present around the nozzle apparatus 8 in the downcomer 31 is sucked into the bell mouth 24. There are two patterns for sucking the cooling water, which is the suction flow, present around the nozzle apparatus 8 into the bell mouth 24 due to the reduction of the static pressure in the throat 25. The first pattern is that the cooling water present above the elbow pipe 19 introduces into the inner cooling water suction passage 17 from the opening portion 18, and reaches the bell mouth 24 through the inner cooling water suction passage 17. In this pattern, the cooling water sucked into the inner cooling water suction passage 17 flows inside of the ejected annular flow. The second pattern is that the cooling water in the downcomer 31 reaches the bell mouth 24 through the outside cooling water suction passage 38 outside of the ejected annular flow. The driving flow ejected from the annular ejection outlet 12 and the cooling water (suction flow) sucked into the bell mouth 24 due to the effect of the driving flow are mixed in the throat 25 while exchanging their momentum, and introduced to the diffuser 26 placed below the throat 25. In the diffuser 26, the passage cross section gradually expands so that the flow of the cooling water (including the driving flow) would not be separated, and its kinetic energy is converted to pressure. In the diffuser 26, the pressure of the cooling water will be higher than the pressure at the position where the cooling water is sucked into the bell mouth 24. The cooling water with the increased pressure is discharged from the diffuser 26 and introduced to the core 3. In the present embodiment, since the joint portion 23 is positioned lower than the top point TP, the upper passage 44 and the lower passage 45 in the elbow pipe 19 are formed toward the outlet end 21, diagonally to the inner cylinder member 15 forming the inner cooling water suction passage 17 in the axial direction of the inner cylinder member 15. From this, pressure loss is reduced in the elbow pipe 19 where the inner cylinder member 15 exists, and the flow speed of the cooling water ejected from the annular ejection outlet 12 is increased. The reduction range of the static pressure in the throat 25 becomes larger, and the flow rate of the cooling water sucked into the bell mouth 24 through the inner cooling water suction passage 17 and the outside cooling water suction passage 38 is increased. This increase in the flow rate of the cooling water improves efficiency for the jet pump 7. This efficiency improvement of the jet pump 7 is specifically explained using FIG. 5. FIG. 5 shows a relationship between the M ratio and the efficiency of the jet pump for the jet pump in the present embodiment and the jet pump of a comparative example. In FIG. 5, the solid line shows the properties of the jet pump 7 in the present embodiment, and the broken line shows the properties of the jet pump of the comparative example. The jet pump of the comparative example uses the nozzle apparatus shown in FIG. 3 of Japanese Patent Laid-open No. 2001-90700 as a nozzle for the jet pump disclosed in U.S. Pat. No. 3,625,820 for a BWR. While the pressurized driving flow hits the inner cylinder of the nozzle apparatus at a right angle in the comparative example, in the jet pump 7, the driving flow flowing through the cooling water passage in the elbow pipe 19 hits the inner cylinder member 15 diagonally as described above. Because of such difference in the driving flows, the pressure loss in the jet pump 7 is less than that of the comparative example, which makes the efficiency of the jet pump 7 more than that of the comparative example. In the present embodiment, since the flow-adjusting plate 22 is disposed in the elbow pipe 19, the pressure loss in the elbow pipe 19 is further reduced. Because of this reduction in the pressure loss, the efficiency of the jet pump 7 is further increased. Since the flow-adjusting plate 22 is disposed to the upper course of the inner cylinder member 15, separation and uneven speed distribution of the flow in the elbow pipe 19 are improved, and the pressure loss in the elbow pipe 19 is reduced. Since the cooling water passages (the upper passage 44 and the lower passage 45) formed in the elbow pipe 19 are diagonal to the inner cylinder member 15 as described above, the driving flow flowing in the cooling water passages hits the outer surface of the inner cylinder member 15 diagonally to the axial direction of the inner cylinder member 15. This causes the stress generated at the contact portion between the inner cylinder member 15 and the elbow pipe 19 to be small. Thus, when the nozzle apparatus 8 is applied to a current BWR, it is not necessary to reinforce the joint portion by making the member particularly thick, or to modify the raiser pipe 34 and the fixture 30. In the present embodiment, since the inner cooling water suction passage 17 is formed in the nozzle apparatus 8, the effect of the pressure reduction in the area inside the ejected annular flow can be effectively used. From this, the flow of the cooling water reaching the bell mouth 24 through the inner cooling water suction passage 17 can be generated. Thus, the flow rate of the cooling water flowing into the bell mouth 24 is increased since the cooling water can flow into the bell mouth 24 through each of the inner cooling water suction passage 17 and the outside cooling water suction passage 38. Since the inner cooling water suction passage 17 is disposed in the axial direction of the RPV 2 and the opening portion 18 opens upward, the flow power of the cooling water moving down in the downcomer 31, supplied to the inner cooling water suction passage 17, can be effectively used to increase the suction power of the jet pump 20. From this, the rate of the cooling water sucked into the throat 25 can be increased. In addition, since the outer funnel portion 40, the outer diameter of which diminishes downward, is used in the nozzle portion 9, the nozzle apparatus 8 has a structure which allows the cooling water moving down in the downcomer 31 to be easily sucked into the bell mouth 24 through the outside cooling water suction passage 38. From this also, the flow rate of the cooling water flowing into the bell mouth 24 can be increased, thus the efficiency of the jet pump 7 can be increased. In a BWR, the flow rate of the cooling water to be supplied to the core 3 (core flow rate) is adjusted by controlling the rotation speed of the recirculation pump 33. By improving the M ratio and the efficiency of the jet pump, the core flow rate can be increased with less recirculation pump power. Thus, the power consumption required for operation of the recirculation pump 12 can be reduced. In addition, when a power uprate of a nuclear reactor implemented in the U.S. is to be implemented, the core flow rate can be further increased without increasing the capacity of the recirculation pump 33 by using the jet pump 7 in the present embodiment to the current nuclear reactor, which jet pump 7 increases the M ratio and the efficiency of the jet pump. For this reason, the power uprate can be easily handled by merely replacing the nozzle of each jet pump in the current nuclear reactor to the nozzle apparatus 8. Furthermore in the present embodiment, since the inverted U-shaped elbow pipe 19 is connected to the nozzle apparatus 8, each elbow pipe 19 connected to each nozzle apparatus 8 of two jet pumps 7 can be connected to the single raiser pipe 34 disposed in the downcomer 31, adjacent to the two jet pumps 7. Because of this, the space between the jet pumps 7 can be made equal to that of the current BWR. A jet pump according to second embodiment, which is another embodiment of the present invention is explained using FIG. 6. A jet pump 7A in the present embodiment has a nozzle apparatus 8A replacing the nozzle apparatus 8 of the jet pump 7 in the first embodiment. The other structure of the jet pump 7A is the same as the jet pump 7. The jet pump 7A is disposed in the downcomer 31 in the RPV 2 of a BWR also. The nozzle apparatus 8A has an inner cylinder member 15A replacing the inner cylinder member 15 of the nozzle apparatus 8, having a curved surface 46 on the inner surface of the upper end portion. The other structure of the nozzle apparatus 8A is the same as the nozzle apparatus 8. Because such inner cylinder member 15A is provided, the passage cross section of an opening portion 18A gradually diminishes downward due to the formation of the curved surface 46. The opening portion 18A is formed at the upper end portion of the inner cooling water suction passage 17 formed in the connected inner cylinder member 15A, the inner funnel portion 41, and the inner cylinder member 11. The inlet end 20 of the elbow pipe 19 is connected to the raiser pipe 34 using the fixture 30 in the same manner as the first embodiment. The flow-adjusting plate 22 is disposed in the elbow pipe 19. The outlet end 21 of the elbow pipe 19 is fixed to the upper end of the outer cylinder member 14 of the nozzle header portion 13 by welding. In the jet pump 7A in the present embodiment also, the joint portion 23 which is at the highest position in the joint portion between the inner cylinder member 15A and the elbow pipe 19, is located lower than the top point TP on the outer surface of the elbow pipe 19. Thus, the cooling water passages (the upper passage 44 and the lower passage 45) formed in the elbow pipe 19 are formed in such a way that the driving flow flowing toward the outlet end 21 hits the inner cylinder member 15A diagonally to the axial direction of the inner cylinder member 15A in the elbow pipe 19. In such jet pump 7A in the present embodiment also, the pressure loss in the elbow pipe 19 is reduced and efficiency of the jet pump is increased in the same manner as the jet pump 7. Since the jet pump 7A has the flow-adjusting plate 22, the efficiency of the jet pump is further increased. In the present embodiment in which the curved surface 46 is formed at the opening portion 18A of the inner cooling water suction passage 17, the following effects can occur. The cooling water sucked into the bell mouth 24 from the inner cooling water suction passage 17 is sucked in the inner cooling water suction passage 17 from a wider range than the opening size of the opening portion 18A. When the edge angle of the upper end of the inner cylinder member 15A is sharp, pressure loss will occur due to the abrupt change in the flow direction of the sucked cooling water; and in addition, the pressure loss may be further increased by possible flow separation. By forming the curved surface 46 on the inner surface of the upper end portion of the inner cylinder member 15A, the change in the flow direction of the sucked cooling water will be smooth as well as preventing flow separation, and thus, the pressure loss can be reduced. The larger the passage cross section of the opening portion 18A sucking the cooling water, the easier for the cooling water to be sucked into the inner cooling water suction passage 17. On the other hand, the smaller the outer diameter of the inner cylinder member 15A is, the larger the passage cross section of the annular header portion 16 formed in the nozzle header portion 13 will be. Since the flowing speed of the driving flow flowing in the annular header portion 16 can be reduced, the pressure loss in the nozzle header portion 13 can be decreased. Since the curved surface 46 is formed at the opening portion 18A of the inner cooling water suction passage 17, the passage cross section of the opening portion 18A can become larger and the outer diameter of the inner cylinder member 15A can become smaller. As discussed above, the reduction of passage drag at the opening portion 18A of the inner cooling water suction passage 17 and the reduction of the pressure loss inside the nozzle apparatus 8A can further improve the efficiency of the jet pump. A jet pump according to third embodiment which is another embodiment of the present invention is explained using FIGS. 7 and 8. A jet pump 7B of the present embodiment has a nozzle apparatus 8B replacing the nozzle apparatus 8 of the jet pump 7 in the first embodiment. The other structure of the jet pump 7B is the same as the jet pump 7. The jet pump 7B is disposed in the downcomer 31 in the RPV 2 of a BWR also. An inner cylinder member 15B provided to the nozzle apparatus 8B is longer than the inner cylinder member 15 provided to the nozzle apparatus 8 in the first embodiment. A protruding portion 47 is formed at the upper end portion of the inner cylinder member 15B. Since the inner cylinder member 15B is long, when the outlet end 21 of the elbow pipe 19 is welded to the upper end of the outer cylinder member 14, the protruding portion 47 protrudes upward from the outer surface of the elbow pipe 19. The joint portion 23 located at the highest position in the joint portion between the inner cylinder member 15B and the elbow pipe 19 is positioned lower than the top point TP on the outer surface of the elbow pipe 19. A curved surface 46A is formed on the inner surface of the upper end portion of the protruding portion 47. An opening portion 18B formed at the upper end portion of the inner cooling water suction passage 17 formed inside the connected inner cylinder member 15B, the inner funnel portion 41 and the inner cylinder member 11 is formed in the protruding portion 47. The cross section of the opening portion 18B gradually diminishes downward due to the formation of the curved surface 46A. The jet pump 7B in the present embodiment can also obtain the effects generated by the jet pump 7 in the first embodiment. In the present embodiment, since the inner cooling water suction passage 17 protrudes upward from the outer surface of the elbow pipe 19, the inner diameter of the opening portion 18B of the inner cooling water suction passage 17 can be made larger without being limited by the elbow pipe 19. Although the inner diameter of the opening portion 18B is large, the passage cross section of the protruding portion 47 can be moderately made smaller. Because of this, the outer diameter of the lower part of the inner cylinder member 15B below the protruding portion 47 can be made smaller. In the present embodiment, an inner diameter d2 at the upper end of the opening portion 18A is larger than an inner diameter d1 of the protruding portion 47 at the lower end of the protruding portion 47 (fixing position of the inner cylinder member 15B to the elbow pipe 19). Thus, drag in the inner cooling water suction passage 17 is reduced. From above, pressure loss in the annular header portion 16 can be reduced while increasing the suction rate of the cooling water into the inner cooling water suction passage 17. The present embodiment can improve efficiency of the jet pump. In the present embodiment, the effects generated in the first embodiment can be obtained. In the first embodiment and second embodiment, each upper end of the opening portions 18 and 18A are tilted, so the shape of each upper end of these openings is oval. However, in the third embodiment, the shape of the opening portion 18B is circular. Because of this, the inner cooling water suction passage 17 can evenly suck the cooling water in the circumferential direction of the passage. In the present embodiment such as this, the pressure loss at the time of the cooling water being sucked into the inner cooling water suction passage 17 can be further reduced, and the efficiency of the jet pump can be further improved.
043026800	description	In FIGS. 1 and 2 in each case the left half of the figure shows the shielding cover in the closed condition and the right half of the figure reproduces the shielding cover in the open condition. The cover of the invention can comprise, consist essentially of or consist of the stated parts. DESCRIPTION OF THE PREFERRED EMBODIMENTS The shielding container 1 has an outer transportation cover 2 flanged in any manner on the container 1 to securely include the free radioactivity by means of seals 3 and to protect mechanically against outside influences. Below the transportaion cover 2 there is located the shielding cover 4 for securely sealing the gamma and neutron rays from the irradiated fuel elements against the environment. The shielding cover 4 consists of fixed cover portion 5 and a moveable cover portion 6 which are joined together in such manner that they both twist toward each other as well as also being able to be spreaded. The moveable cover portion 6 has distributed at its periphery claws 7 which fit into corresponding openings 8 of the top of the container 9. They are fastened on the container by twisting according to the principle of the bayonet. The connection between the fixed cover portion 5 and the moveable cover portion 6 of the shielding cover 4 takes place with a screw 10 carried into the moveable cover portion 6 and a pin 11 fitting into the fixed cover portion. By turning in the screw 10 the moveable cover portion 6 is moved away from the fixed cover portion 5 so that a twisting of the moveable cover portion 6 is no longer possible and the seal 12 is so fixed between the fixed cover portion 5 and the container 1 that there is guaranteed the sealing of the container contents against the outer world. To open the shielding cover 4 the spread between the fixed cover portion 5 and the moveable cover portion 6 is decreased through turning the screw 10 outwardly so that by turning of the moveable cover portion around a length of claw both can be raised and the shielding cover 4 can be lifted off. Moreover, screw 10 can be operated either manually or also mechanically by remote control. By further turning out of the screw 10 the moveable cover portion 6 and the fixed cover portions 5 are supported via the pin 11. Thereby the seal 13 tightens the gap 14 between the two cover portions and thus prevents a contamination of this gap. The transportation cover 2 has the function correspondingly to safely seal in the container contents of the transportation container order. It is removed inside the control area for loading and unloading since the shielding cover 4 guarantees a sufficient protection in this area. The transportation cover 2 is secured at the flange of the top 9 of the container with screws (not shown), preferably clamping screws, distributed around the periphery of the transportation cover, through which the necessary compressive strength for tightening the seal 3 can be applied. This seal 3 is so designed that it fulfills the required packing both in the failure of the seal 12 and also in all loads occurring in accidents of design. The function of the cover system of the invention will be further explained in connection with an unloading process employing dry unloading. First the transportation cover 2 is removed in the control area and the transportation container 1 flanged on the container flange under a hot cell lock. The shielding cover 4 then is connected with the hot cell cover and the spread between the two cover portions 5 and 6 of the shielding cover 4 lowered by remote control turning of the screw 10. The moveable cover portion 6 is turned in the opening position and the two cover portions 5 and 6 brought together by further turning of the screw 10 so that the gap 14 is made tight by the seal 13. The shielding cover 4 can now be turned with the hot cell cover in the hot cell without the surface of the shielding cover 4 and the gap 14 being contaminated (double cover system). The cover system of the invention has a number of advantages over the known covers for shielding containers. The dry loading and unloading into or on a hot cell is possible without danger of contamination of the cover system, exactly as the wet loading and unloading in a water vessel. In an accident the transportation cover 2 is not loaded with the weight of the contents of the container and the shielding composition of the shielding cover 4. The dimensioning of the set screw 10 therefore can by itself alone adjust for the sealing after the required initial stress. The seal 3 guaranteeing the tightness of the container system is substantially shielded from gamma and neutron irradiation. The operating temperatures for this sealing system therefore are moderate. The seal 12 protects it in the normal operation extensively from radioactive gases and steam (in wet transport) which largely prevents a premature aging. Besides this sealing system 3 is easily accessible for maintenance and inspection. By constructing the shielding cover 4 as a bayonet closure to open the cover there is only needed a central turning movement which can be carried out readily either by remote control or manually. Because of the division of the shielding cover in two parts it is not necessary to turn the entire cover. The entire disclosure of German priority application No. P 28 30 111.3 is hereby incorporated by reference.
	description	The present invention relates generally to nuclear reactors, and more particularly to mitigating acoustic loads in a nuclear reactor. In boiling water nuclear reactor (BWR), reactor coolant flows through a series of plenums starting with a lower core plenum, the nuclear core itself and an upper core plenum, each lying in communication with one another. The upper core plenum lies below a shroud head which has a series of standpipes that lead steam/water to a series of separators where the two-phase mixture of steam and water is separated. The separated water flows downwardly in an annulus about the core shroud for recirculation. The separated steam flows upwardly of the reactor through a steam dryer for flow outside of the reactor vessel to drive a turbine for generating power. In BWR's, this flowing mixture of vapor and liquid must be separated efficiently to provide the dry steam required for steam turbine generators. Typical reactor designs employ primary separators, each of which includes a standpipe connected to the upper core shroud and which standpipe is topped with a helical flow diverter to create a swirl flow into an enlarged separation barrel section. The resultant radial acceleration field causes the higher density liquid to move outward and flow as a film on the separation barrel. Radial pick-off rings are provided at one or more axial positions along the barrel to intercept the liquid film flow and separate it from the interior vapor flow. Discharge passages direct the separated water to a water pool which partially submerges the primary separators. One of the sources of loading that has destroyed or damaged equipment is acoustic resonance of the fluid inside a standoff pipe, such as a safety relief valve. The safety relieve valve, or valves, with steam flow past their entrances, and the acoustic resonance which naturally occurs, causes acoustic pressures to travel upstream, causing damage to devices, for example, the steam dryers. Previous attempts to reduce damage to devices such as steam dryers have included predicting or estimating the loading on the steam dryer using Finite Element Analysis (FEA), and computing the stress on the dryer, and modifying the dryer to decrease the computed stresses. Another attempt to reduce the damage to equipment such as steam dryers has included a Helmholtz resonator provided on the relief valves. However, the Helmholtz resonator is a large cantilevered bottle-shaped device which is difficult to support in the environment of a nuclear power generating station. In one embodiment of the invention, a system for reducing an acoustic load of a fluid flow comprises a first pipe to carry the fluid flow; a standpipe connected to the first pipe at an opening in the first pipe; and a standpipe flow tripper provided in the standpipe. The flow tripper comprises an edge extending through the opening into the flow on a downstream side of the opening. In another embodiment of the invention, a method of reducing an acoustic load of a standing wave in a standpipe connected to a first pipe configured to carry a flow comprises disrupting the flow in the first pipe at an upstream side of an opening in the first pipe to which the standpipe is connected. Referring to FIGS. 1-5, a steam line pipe 1, for example, in a nuclear power generating station such as a boiling water reactor (BWR) comprises pipe flanges 2 at opposite ends for connection of the steam line pipe 1 to a steam delivery line. A pressure sensor 27 may be provided in the steam line pipe 1 to measure a pressure of steam carried by the steam line pipe 1. A standpipe 32 is connected to the steam line pipe 1 for mounting of a safety relief valve (not shown) to a pipe flange 8 of the standpipe 32. A pressure sensor 28 is provided on the pipe flange 8 to measure pressure of the steam in the standpipe 32. Referring to FIGS. 3-5, the standpipe 32 may be connected to the steam line pipe 1 by a pipe base 3. A first pipe flange 7 is connected to the pipe base 3. A second pipe flange 7 is connected to the first pipe flange 7 by fasteners, for example bolts 12 and nuts 14. A spacer 17 is provided between the first and second pipe flanges 7. Each side of the spacer 17 may be sealed with the pipe flange 7 by a seal 9, for example a gasket. As shown in FIGS. 4 and 5, the first and second pipe flanges 7 and the spacer 17 may be aligned by alignment pins 10. Referring to FIGS. 2, 3 and 5, the standpipe 32 further includes a pipe 4. The pipe 4 may be connected at one end to the pipe flange 7, for example by welding. A pipe flange 5 may be connected to the pipe 4 at the other end, for example by welding. The pipe flange 8 for connection of a safety relief valve (not shown) is connected to the pipe flange 5, for example by fasteners, such as bolts 13 and nuts 14. A seal 9, for example a gasket, may be provided between the pipe flanges 5, 8. The pressure sensor 28 may be provided in a tap of the pipe flange 8 for measuring a pressure in the standpipe 32. Although the pipe 4 is shown as connected to the pipe flanges 7, it should be appreciated that the pipe flange 5, the pipe 4 and the second pipe flange 7 may be formed as a one piece unitary structure. Referring to FIGS. 3 and 4, a standpipe flow tripper assembly 11 is provided in the standpipe 32. As shown in FIG. 3, the standpipe flow tripper assembly 11 includes a flow tripper, or disrupter, or spoiler 6. A first end of the spoiler 6 may be provided between the seals 9 and within the spacer 17. As shown in FIGS. 6-8, the first end of the spoiler 6 may be attached to the spacer 17, for example by welding 23. As shown in FIG. 9, the flow spoiler 6 may have a semi-circular cross section. AS shown in FIG. 3, the second end of the flow spoiler 6 extends into the steam line pipe 1 through an opening, or side-branch entrance, 33. The flow spoiler 6 is provided on a downstream side of the opening 33 with respect to a flow F that the steam line pipe 1 is configured to carry. The flow spoiler 6 has a trailing edge 31. Placing the trailing edge 31 of the flow spoiler 6 on the downstream side, instead of the upstream side, prevents the flow spoiler from interfering with the actuation of the safety relief valve. Referring to FIG. 10, a flow tripper, disrupter, or spoiler 6 according to another embodiment of the invention includes a trailing edge 31 that is offset. The first end of the flow spoiler 6 may be attached to the spacer 17 between the seals 9 in the manner described above, and the trailing edge 31 will be placed further downstream of the opening, or side-branch entrance, 33 of the steam line pipe 1 than the embodiment discussed above. The position of the trailing edge 31 of the flow spoiler 6 may be adjusted depending on the acoustic resonance frequency of the standoff pipe or relief valve. The flow spoiler 6 disrupts the mutual resonance of the shear layer instability of flow past the opening 33 of the standpipe 32, and the acoustic resonance of the standpipe 32 or relief valve. The flow instability can not lock onto the acoustic mode of the standpipe 32 or relief valve entrance when the flow tripper, disrupter, or spoiler 6 is in place. In other words, the spoiler 6 disrupts the flow from exciting the acoustic standing wave. The flow spoiler 6 thus prevents loads in the standpipe 32 or the safety relief valve from becoming high. The standpipe flow tripper assembly described herein also does not introduce any flow blockage (i.e. does not affect flow to downstream standpipes), is passive in its reduction or removal of the acoustic loading, and requires no external support. The standpipe flow tripper assembly described herein may thus be implemented very easily into existing plants. The standpipe flow tripper assembly also prevents high loading in the main steam lines and on such devices as steam dryers at flow conditions at which such loading would normally occur. The standpipe flow tripper assembly also would enable or facilitate power uprates in nuclear power plants by eliminating a source of concern in power uprates, which is the increase of acoustic loads, with the attendant risk to steam dryers and other equipment. While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
	claims	1. An electron microscope comprising:an electron gun for emitting an electron beam;a condenser lens for focusing the beam onto a specimen;first deflection means for deflecting the beam hitting the specimen to vary electron beam position on the specimen;an energy filter for energy-dispersing the electron beam ejected from the specimen in a given direction to form a spectrum;a projector lens for projecting the spectrum formed by the filter onto an image detector;second deflection means for deflecting the beam ejected from the specimen in such a way that the spectrum is projected onto the detector irrespective of the electron beam position on the specimensaid first deflection means has a first deflector disposed between the electron gun and the specimen and a deflection signal supply circuit for supplying a beam deflection signal to a power supply that drives the first deflector;said second deflection means has a second deflector disposed between the specimen and the image detector and a spectral position correcting signal supply circuit for supplying a spectral position correcting signal to a power supply that drives the second deflector;said spectral position correcting signal supply circuit for producing a spectral position correcting signal corresponding to said beam deflection signal; andsaid spectral position correcting signal supply circuit having a scanning direction rotating circuit for rotating said beam deflection signal and a scanning amplitude varying circuit for varying the amplitude of the beam deflection signal rotated by the scanning direction rotating circuit. 2. An electron microscope as set forth in claim 1, wherein said second deflection means deflects the electron beam ejected from the specimen such that said spectrum is projected at a given position on said image detector irrespective of the electron beam position on the specimen. 3. An electron microscope as set forth in claim 1, wherein said second deflector is disposed between the energy filter and the image detector. 4. An electron microscope as set forth in claim 3, further including:multiple stages of electron lenses disposed between said specimen and the energy filter; andan excitation signal supply circuit for supplying an excitation signal to a power supply that drives the electron lenses,wherein said spectral position correcting signal supply circuit produces a spectral position correcting signal corresponding to said beam deflection signal and said excitation signal. 5. An electron microscope as set forth in claim 1, wherein said second deflector is disposed between the projector lens and the image detector, and wherein said spectral position correcting signal supply circuit produces a spectral position correcting signal corresponding to the excitation signal supplied to a power supply that drives said projector lens. 6. An electron microscope as set forth in claim 4, wherein said second deflector is disposed between the projector lens and the image detector, and wherein said spectral position correcting signal supply circuit produces a spectral position correcting signal corresponding to the excitation signal supplied to a power supply that drives said projector lens. 7. An electron microscope as set forth in claim 1, wherein said second deflector is disposed between the specimen and the energy filter. 8. An electron microscope as set forth in claim 1, further including means for creating an EELS profile based on a spectral image taken in by said image detector.
049960202	summary	BACKGROUND OF THE INVENTION 1. Field of the invention The present invention relates to a method of restraining a diffusion of tritium and an apparatus for same. 2. Description of the Related art In general, a fast breeder reactor comprises an arrangement of devices as shown in FIG. 3. In FIG. 3, a reactor vessel made of stainless steel is indicated at 1. The reactor vessel 1 contains a reactor core 2 in which a nuclear fuel assembly comprising a fissionable material is placed. The reactor core 2 receives a control rod 3 including boron so that the control rod 3 can be pulled up and inserted into the reactor core 2 from above. The fast breeder reactor has a primary cooling system piping 4 made of stainless steel and causing liquid sodium as a coolant to pass through the reactor core 2 in the reactor vessel 1 and to circulate by means of a pump 5 between the reactor vessel 1 and an intermediate heat exchanger 6. The fast breeder reactor also has a secondary cooling system piping 7 made of stainless steel and causes liquid sodium as a coolant of a secondary cooling system to circulate by means of a pump 8 between the intermediate heat exchanger 6 and a steam generator 9. A steam system piping feeding water to the steam generator 9 to receive steam therefrom is indicated at 10. Both the primary and secondary cooling system pipings 4 and 7 have heat reserving means. The arrangement of each of the heat reserving means is as follows: FIG. 4 illustrates the arrangement of a piping 11 which is assumed to represent each of the primary and secondary cooling system pipings 4 and 7. As shown in FIG. 4, a stainless steel strip 13 surrounds both the piping 11 made of stainless steel in view of both resistance against corrosion caused by liquid sodium and a high-temperature strength and a preheater 12 arranged in parallel to the piping 11, a heat reserving material 14 surrounds the stainless steel strip 13, and a thin steel strip 15 surrounds the heat reserving material 14. The thickness of each of the stainless steel strip 13 and the steel strip 15 is normally about 0.1 mm-0.2 mm. The reserving material 14 normally is a mixture including calcium oxide or silicon oxide as a main component. Turning back to FIG. 3, a fission reaction in the reactor or a nuclear transformation caused by neutron irradiation of the boron used as a moderator of the control rod 3 produces tritium. For example, in a nuclear reactor of one million KW tritium of about 1 g/year occurs. The tritium is mixed with liquid sodium passing through the reactor core 2 and transferred through the primary cooling system piping 4 to the intermediate heat exchanger 6. Then, the tritium permeates the wall of a heat-transfer pipe of the intermediate heat exchanger 6 and enters liquid sodium contained in the secondary cooling system piping 7 to reach the steam generator 9. Thus, the tritium permeates the pipings and devices, so that the tritium tends to readily permeate and diffuse in atmospheres outside of the devices. In particular, it is well known that tritium permeates stainless steel used to constitute the devices of a nuclear power plant. Thus, tritium permeating e.g. the piping 11 inside to outside permeates the heat reserving means to diffuse to the outside thereof. Since as described above, the tritium which has once diffused continues to diffuse and in the worst case, might diffuse in the atmosphere, the diffusion of the tritium must be restrained. SUMMARY OF THE INVENTION An object of the present invention is to provide a method of restraining a diffusion of tritium and an apparatus for same. In order to achieve this object, a method of the invention for restraining a diffusion of tritium comprises the step of disposing a hydrogen-absorbing metal in a tritium passage in the direction of diffusion of tritium so that the hydrogen-absorbing metal absorbs tritium to be diffused. An apparatus of the invention for restraining a diffusion of tritium, comprises a hydrogen-absorbing metal surrounding a device of an fast breeder reactor. According to the invention, since the hydrogen-absorbing metal well absorbs tritium constituting an isotope of hydrogen, the hydrogen-absorbing metal disposed in the tritium passage in the direction of diffusion of tritium absorbs and captures the tritium, the tritium is restrained in diffusing anywhere.
046541926	abstract	A temperature-actuated apparatus is disclosed for releasably supporting a safety rod in a nuclear reactor, comprising a safety rod upper adapter having a retention means, a drive shaft which houses the upper adapter, and a bimetallic means supported within the drive shaft and having at least one ledge which engages a retention means of the safety rod upper adapter. A pre-determined increase in temperature causes the bimetallic means to deform so that the ledge disengages from the retention means, whereby the bimetallic means releases the safety rod into the core of the reactor.
	claims	1. A device designed to be used for neutron imaging immersed in a medium containing specimens to be analyzed, comprising: a first converter comprising a first material capable of converting thermal neutron radiation into remnant beta radiation by its neutron activation and a second converter comprising a second material capable of absorbing thermal neutron radiation by capture and capable of converting a remnant beta radiation into light radiation, said second converter being in contact with said first converter, andfurther comprising a support comprising hydrogenated species on which said second converter is positioned, said support being transparent to said light radiation. 2. The device designed to be used in neutron imaging as claimed in claim 1, wherein the first material comprises dysprosium. 3. The device designed to be used in neutron imaging as claimed in claim 1, wherein said second converter comprises a scintillator material which is a compound containing gadolinium, which can be of the type (Tb doped) Gd2O2S. 4. The device designed to be used in neutron imaging as claimed in claim 3, wherein the scintillator material is mixed with an organic binder. 5. The device designed to be used in neutron imaging as claimed in claim 1, wherein the thickness of the first converter is of the order of a hundred microns. 6. The device designed to be used in neutron imaging as claimed in claim 1, wherein the thickness of the second converter is of the of the order of ten microns. 7. The device designed to be used in neutron imaging as claimed in claim 1, wherein the support comprises a transparent material, with hydrogenated species, of the polymethylmethacrylate type, where said support can have a thickness of the order of a few millimeters. 8. A leak-tight system designed to be used in neutron imaging immersed in a medium comprising a device as claimed in claim 1 and a vessel leak-tight to said medium, incorporating the first converter, the second converter, and the support. 9. A method for neutron imaging immersed in a medium and using a system as claimed in claim 8, comprising:immersing said system in a liquid medium comprising specimens to be analyzed;irradiating said system by a flux of neutrons;removing said system from said liquid medium;removing said converters from said leak-tight vessel; andrecording of the scintillation generated by the second converter. 10. The neutron imaging method as claimed in claim 9, wherein the specimens to be analyzed are nuclear fuels.
055286461	abstract	A sample vessel for X-ray microscopes comprising a first silicon base plate having an entrance window covered with a thin film of silicon nitride, and a second silicon base plate which has an exit window covered with a thin film of silicon nitride and matched with the entrance window. The second silicon base plate being connected the first base plate by way of a spacer so as to form a sealed space capable of accommodating samples to be observed. Disposed in the space is a mesh member made of a wire material having an angle of contact with water smaller than 90.degree. at a location adjacent to the thin film of silicon nitride covering the entrance window or a thin film of aluminium is evaporation-coated over the thin film of silicon nitride. This sample vessel makes it possible to enhance mechanical strength of the thin film of silicon nitride and limits shifting of samples within very narrow ranges with water films formed in meshes of the mesh member, thereby remarkably facilitating observation of the samples with X-rays and soft X-rays.
	abstract	An iterative drilling simulation method and system for enhanced economic decision making includes obtaining characteristics of a rock column in a formation to be drilled, specifying characteristics of at least one drilling rig system; and iteratively simulating the drilling of a well bore in the formation. The method and system further produce an economic evaluation factor for each iteration of drilling simulation. Each iteration of drilling simulation is a function of the rock column and the characteristics of the at least one drilling rig system according to a prescribed drilling simulation model.
	description	The present invention relates to a radiation detector detecting an X-ray, y-ray, etc., and particular to a support member supporting a collimator plate to be provided on the radiation source side of the radiation detector in order to remove scattered radiations. The present invention relates also to an X-ray Ct apparatus provided with such a radiation detector. An X-ray CT (Computed Tomography) apparatus that is one of medical image diagnostic apparatuses reconstructs a tomographic image of an object using projection data from multiple angles that can be obtained by rotating an X-ray tube device irradiating an X-ray to the object and an X-ray detector detecting distribution of the X-ray dose transmitted through the object as the projection data around the object to display the reconstructed tomographic image. The image to be displayed on the X-ray CT apparatus draws organ shapes inside the object and is used for image diagnosis. As a radiation detector represented by an X-ray detector used for an X-ray CT apparatus, an indirect-conversion-type detector, which is provided with a detection element in which a phosphor element such as a ceramic scintillator and a light detecting element such as a photodiode are combined, is used mainly. Also, a direct-conversion-type detector, which is provided with a semiconductor element as a detection element, has been recently used. In either type of the radiation detector, a structure in which approximately one thousands of detection element s are arranged on an arc around an X-ray focus in the rotation plane and a plurality of the detection element arrays are further arranged in the rotation axis direction is adopted. Also, a number of collimator plates are provided along the rotation axis direction on the X-ray tube device side of the X-ray detector in order to remove a scattered X-ray from an X-ray transmitted through an object. The collimator plates are made of thin metal plates that can shield an X-ray sufficiently and arranged radially toward the X-ray focus. In a modern X-ray CT apparatus, it is promoted that the rotation speed and the number of detection element arrays are increased mainly in order to shorten an examination time. Increasing the rotation speed increases a centrifugal force applied to a collimator plate, and increasing the number of detection element arrays extends a length of a collimator plate in the rotation axis direction, which results in reducing the collimator plate strength. Therefore, as the rotation speed and the number of detection element arrays are increased, a collimator plate can be easily deformed during CT scanning. The deformed collimator plate changes an amount of X-ray incident on a detection element, which causes artifact generation on a tomographic image. The patent literature 1 discloses an X-ray detector capable of reducing the collimator plate deformation and an X-ray CT apparatus therewith. PTL 1: International Patent No. 2011/074470 In PTL 1, there is a groove provided on a resin support plate disposed parallel to an X-ray incident plane of an X-ray detector, and one end of a collimator plate is connected by engaging it in the groove provided along the rotation axis direction. In such a structure, as the number of the detection element arrays increases, the collimator plate and the groove extend the lengths in the rotation axis direction, which makes it difficult to engage the collimator plate in the groove. Therefore, the purpose of the present invention is to provide a radiation detector and an X-ray CT apparatus in which collimator plates can be easily arranged. In order to achieve the above purpose, the present invention is characterized by comprising radiation detection element arrays in which a plurality of radiation detection elements detecting a radiation generated from a radiation source are arranged in a first direction and a second direction orthogonal to the first direction, collimator plates arranged along the first direction on the radiation source side of the radiation detection element arrays to remove scattered radiations, and collimator plate support members that have grooves supporting the collimator plate and are arranged along the second direction between the radiation detection elements. According to the present invention, it can provide a radiation detector and an X-ray CT apparatus in which collimator plates can be easily arranged. The radiation detector related to the present embodiment is characterized by comprising radiation detection element arrays in which a plurality of radiation detection elements detecting a radiation generated from a radiation source are arranged in a first direction and a second direction orthogonal to the first direction, collimator plates arranged along the first direction on the radiation source side of the radiation detection element arrays to remove scattered radiations, and collimator plate support members that have grooves supporting the collimator plate and are arranged along the second direction between the radiation detection elements. Also, there are even numbers of the collimator plate support members, and they are characterized by being provided in symmetric positions on the basis of the central position in the first direction. Also, a width between radiation detection elements where the collimator plate support members are arranged is characterized by being wider than a width between radiation detection elements where the collimator plate support members are not arranged. Also, the radiation detection elements are characterized by that they are composed of scintillator elements for generating a visible light when a radiation is incident as well as light detection elements for outputting an electrical signal when the visible light is incident, that reflectors for reflecting the visible light are provided between scintillator elements, and that the collimator plate support members are composed of the same material as the reflectors. Also, the X-ray CT apparatus related to the present embodiment is characterized by comprising the radiation source, the described radiation detector disposed opposite to the radiation source to detect a radiation transmitted through an object, a rotating disk equipped with the radiation source and the radiation detector and rotating around the object, an image reconstruction device for reconstructing a tomographic image of the object based on a transmitted radiation amount detected by the radiation detector from multiple angles, and an image display device for displaying the tomographic image reconstructed by the image reconstruction device. Also, a position where collimator plate support members of the radiation detector are arranged is characterized by being a joint position of a maximum slice thickness during image reconstruction. Hereinafter, the radiation detector and the X-ray CT apparatus of the present invention will be described in detail using the diagrams. Additionally, the repeated explanations of the components with the same functions are omitted by providing the same symbols in the following descriptions and the attached diagrams. Also, in order to help find a direction of each diagram, the XYZ coordinate system is shown in the lower left of each diagram. (First Embodiment) First, the overall configuration of the X-ray CT apparatus of the present invention that is an example of medical image diagnostic apparatuses will be described using FIG. 1. FIG. 1 is a block diagram showing the overall configuration of the X-ray CT apparatus 1. As shown in FIG. 1, the X-ray CT apparatus 1 comprises the scan gantry unit 100 and the operation unit 120. The scan gantry unit 100 comprises the X-ray tube device 101, the rotating disk 102, the collimator 103, the X-ray detector 106, the data collection device 107, the bed device 105, the gantry controller 108, the bed controller 109, the X-ray controller 110, and the high voltage generating device 111. The X-ray tube device 101 is a device for irradiating an X-ray to an object placed on the bed device 105. The collimator 103 is a device for restricting a radiation range of an X-ray irradiated from the X-ray tube device 101. The rotating disk 102 is equipped with the X-ray tube device 101 and the X-ray detector 106, comprises the opening 104 for accommodating the object placed on the bed device 105, and rotates around the object. The X-ray detector 106 is a device for measuring spatial distribution of transmitted X-rays by detecting an X-ray transmitted through an object placed opposite to the X-ray tube device 101, in which many X-ray detection elements are arranged in two dimensions of the circumferential direction in the rotation plane (XY plane) of the rotating disk 102 and the rotation axis direction (parallel to the Z axis). Additionally, the details of the X-ray detector 106 will be described later. The data collection device 107 is a device for collecting an X-ray amount detected by the X-ray detector 106 as digital data. The gantry controller 108 is a device for controlling the rotation of the rotating disk 102. The bed controller 109 is a device for controlling up, down, left, right, back, and forth movements of the bed device 105. The high voltage generating device 111 is a device for generating a high voltage to be applied to the X-ray tube device 101. The X-ray controller 110 is a device for controlling the output of the high voltage generating device 111. The operation console 120 comprises the input device 121, the image calculation device 122, the display device 125, the storage device 123, and the system controller 124. The input device 121 is a device for inputting an object name, an examination date, scanning conditions, etc. and is specifically a keyboard or a pointing device. The image calculation device 122 is a device for performing a calculation process for measurement data sent from the data collection device 107 to reconstruct a CT image. The display device 125 is a device for displaying a CT image generated by the image calculation device 122 and is specifically a CRT (Cathode-Ray Tube), a liquid crystal display, or the like. The storage device 123 is a device for storing data collected by the data collection device 107 and image data of the CT image generated by the image calculation device 122 and is specifically an HDD (Hard Disk Drive) or the like. The system controller 124 is a device for controlling these devices, the gantry controller 108, the bed controller 109, and the X-ray controller 110. The X-ray controller 110 controls the high voltage generating device 111 based on scanning conditions input from the input device 121, such as a tube voltage and a tube current particularly, which supplies predetermined electric power from the high voltage generating device 111 to the X-ray tube device 101. The X-ray tube device 101 irradiates an X-ray according to the scanning conditions to an object using the supplied electric power. The X-ray detector 106 detects an X-ray irradiated from the X-ray tube device 101 and transmitted through the object using many X-ray detection elements to measure distribution of the transmitted X-ray. The rotating disk 102 is controlled by the gantry controller 108 and rotates based on scanning conditions input from the input device 121, such as a rotation speed particularly. The bed device 105 is controlled by the bed controller 109 and operates based on scanning conditions input from the input device 121, such as a helical pitch particularly. By repeating an X-ray irradiation from the X-ray tube device 101 and a measurement of distribution of transmitted X-rays using the X-ray detector 106 together with rotation of the rotating disk 102, projection data from various angles are acquired. The projected data is associated with a view that shows each angle and a channel (ch) number as well as an array number that are detection element numbers of the X-ray detector 106. The acquired projection data from various angles is transmitted to the image processing device 122. The image processing device 122 performs a back projection process for the transmitted projection data from various angles to reconstruct a CT image. The CT image acquired by the reconstruction is displayed on the display device 125. The X-ray detector 106 will be described using FIG. 2. FIG. 2 is a diagram showing the positional relationship between the X-ray focus 201 and the X-ray detector 106. The X-ray detector 106 comprises the scattered radiation remover 202 and the detection element modules 203. The scattered radiation remover 202 removes scattered radiations generated by an object or the like and is configured so that the metal thin plates which can sufficiently shield an X-ray are disposed radially toward the X-ray focus 201 as described later. When an X-ray including scattered radiations is detected by the X-ray detector 106, an X-ray amount reduced by the object is not measured properly, which deteriorates the image quality of the reconstructed tomographic image. The detection element modules 203 measures spatial distribution of an X-ray transmitted through the scattered radiation remover 202 and configured so that X-ray detection elements measuring an X-ray amount are arranged on a flat plate two-dimensionally. The X-ray detector 106 is provided with a plurality of the detection element modules 203, and the respective detection element modules 203 are arranged so as to be a polygonal shape formed by tangent lines of the arc around the X-ray focus 201 on the rotating plane (XY plane) of the rotating disk 102. By thus arranging the respective detection element modules 203, X-ray detection elements are almost arranged on the arc around the X-ray focus 201. Additionally, although the only seven detection element modules 203 are drawn in FIG. 2 in order to simplify the diagram, the number of the detection element modules 203 is not limited to seven. The scattered radiation remover 202 and the detection element modules 203 will be described using FIGS. 3 to 5. FIG. 3 is the A-A cross-sectional diagram in FIG. 2, and the left and right direction is the rotation direction (parallel to the Z axis) of the rotating disk 102. FIG. 4 is the enlarged view in B of FIG. 3. FIG. 5 is the C-C cross-sectional diagram in FIG. 4, and the direction perpendicular to a plane where the diagram is drawn is the rotation axis direction (parallel to the Z axis) of the rotating disk 102. The detection element module 203 comprises the substrate 333, the light detection element array 332, and the scintillator element array 331. The scattered radiation remover 202 comprises the collimator plate 321, the grooved pillar 322, and the collimator plate support members 323. The substrate 333 holds the light detection element array 332 and the grooved pillar 322 and is made of glass epoxy or the like. The light detection element array 332 is installed on the upper plane of the substrate 333, on which the light detection elements 332adetecting light emission of the scintillator element array 331 are arranged two-dimensionally. For example, a photodiode is used for the light detection elements 332a. The scintillator element array 331 is installed on the upper plane of the light detection element array 332, on which the scintillator elements 331a emitting visible lights in an amount according to the X-ray amount by receiving an X-ray light are partitioned with the light reflectors 331 b and arranged two-dimensionally. The scintillator elements 331 and the light detection elements 332a are respectively associated as a pair, and one X-ray detection element is composed of a pair of the scintillator element 331 and the light detection element 332a. The light reflector 331b reflects a visible light emitted by the scintillator element 331a and is formed by fixing white powder such as titanium oxide with a transparent adhesive such as epoxy resin. The thicker the thickness of the light reflector 331b is or the denser the concentration of the white powder in the light reflector 331b is, the more the leakage of a visible light to an adjacent X-ray detection element can be reduced. As the number of X-ray detection elements to be arrayed is increased for the light detection element array 332 and the scintillator element array 331, the yield rate of the components is reduced, or the assembly difficulty is increased. Therefore, in order to avoid these problems, the number of the X-ray detection elements to be arrayed may be increased by dividing and combining at least one of the light detection element array 332, the scintillator element array 331, and the substrate 333. FIG. 3 shows a configuration example where the light detection element array 332 and the scintillator element array 331 are respectively divided into two in the rotation axis direction and combined on one substrate 333. The division mode is not limited to FIG. 3. The collimator plate 321 is a thin metal plate that can shield an X-ray sufficiently and is formed with a plate member of a heavy metal such as tungsten and molybdenum. The collimator plates 321 are arranged so that shadows formed by the collimator plates 321 when the X-ray detector 106 is viewed from the X-ray focus 201 locate along the rotation axis direction (parallel to the Z axis between X-ray detection elements almost arranged on an arc. Specifically, the collimator plates 321 are arranged radially toward the X-ray focus 201 on the rotating plane (XY plane) of the rotating disk 102 or parallel to the rotation axis direction (parallel to the Z axis). By thus arranging the collimator plates 321, direct radiations from the X-ray focus 201 are incident on the X-ray detection elements, scattered radiations generated by an object shielded are shielded by the collimator plates 321, which prevents from being incident on the X-ray detection elements. The grooved pillars 322 support the collimator plate 321 at the end of the rotation axis direction (parallel to the Z axis), have grooves on the sides that are not shown in the diagram, and are installed on the substrate 333. The grooves of the grooved pillars 322 are formed radially toward the X-ray focus 201 in the rotation plane (XY plane). By inserting the collimator plate 321 in the grooves of the grooved pillars 322, the collimator plates 321 are arranged radially toward the X-ray focus 201 in the rotation plane (XY plane). The collimator plate 321 and the grooved pillars 322 may be fixed by an adhesive. The collimator plate support members 323 support the collimator plate 321 from the X-ray detector 106 side and is installed on the scintillator element array 331. The collimator plate support members 323 are arranged between X-ray detection elements aligned along the rotation axis direction (parallel to the Z axis) and have the grooves 324 to insert the collimator plates 321. The grooves 324 are formed between the X-ray detection elements almost aligned on an arc in the rotation plane (XY plane). The shape of the groove 324 may not be limited unless the shape does not hinder the collimator plates 321 to be inserted from being arranged radially toward the X-ray focus 201. Also, the collimator plate 321 inserted in the grooves 324 may be fixed by an adhesive. The thickness of the collimator plate support member 323 is formed thinner than a gap between X-ray detection elements aligned along the rotation axis direction so that the collimator plate support member 323 does not come into contact with the scintillator element 331 a forming an X-ray detection element. In order to reduce absorption of an X-ray by the collimator plate support members 323, it is desirable that the material of the collimator plate support members 323 is, for example, an epoxy resin or the like whose X-ray absorption rate is low. Also, in order to reduce an amount of which the collimator plate support members 323 absorb a visible light generated from the scintillator element 331a, it is desirable that the material of the collimator plate support members 323 is the same as that of the light reflector 331b. Although the collimator plate support members 323 may be arranged in any positions between X-ray detection elements aligned along the rotation axis direction, the collimator plate support members 323 should be desirably arranged in symmetrical positions based on the central position of the X-ray detector in the rotation axis direction. The collimator plate support members 323 are arranged in symmetrical positions in the rotation axis direction, which can support the collimator plates 321 more uniformly. Additionally, the collimator plate support members 323 are arranged desirably in joint positions of the maximum slice thickness in the rotation axis direction during image reconstruction. A multi-slice detector in which a plurality of X-ray detection element arrays are aligned in the rotation axis direction can reconstruct an image for each X-ray detection element array as well as acquire an image with a thick slice by adding plural arrays of measurement data. For example, a 64-array multi-slice detector can acquire 64 images in one measurement as well as acquire four images at a 16-time thickness by adding 16 arrays of measurement data. By the way, if there is a foreign substance like the collimator plate support member 323 in a slice thickness, the image quality of the image with the said slice thickness can be deteriorated. Therefore, in order to prevent such image quality deterioration, it is desirable that the collimator plate support members 323 are arranged in joint positions of the maximum slice thickness during image reconstruction. A specific arrangement example will be described using FIG. 6. FIG. 6 is the schematic diagram of the 64-array multi-slice detector, FIG. 6(a) shows a case of adding 16 arrays of measurement data, and FIG. 6(b) shows a case of adding 8 arrays of measurement data. In a case of forming the maximum slice thickness by 16 arrays in the multi-slice detector of FIG. 6, the Z0 and Z1 positions in the diagram are joint positions of the maximum slice thickness. If the collimator plate support members 323 are arranged in these positions, the collimator plate support members 323 do not exist in a said slice thickness whatever the thickness is. That is, not only when adding 16 arrays of measurement data shown in FIG. 6(a), but also when adding 8 arrays of measurement data shown in FIG. 6(b), or even when adding 4 or 2 arrays of measurement data that is not shown in the diagram, there is no foreign substance like the collimator plate support member 323 in a slice thickness, which can prevent image quality deterioration. Additionally, it may be configured so that the collimator plate support members 323 are arranged out of the center position of the X-ray detector in the rotation axis direction. The center position of the X-ray detector in the rotation axis direction, i.e. the Z0 position in FIG. 6 is a position where a high-quality tomographic image is easily acquired because an X-ray incident on the X-ray detection element is approximately orthogonal to the incident plane. If there is a foreign substance like the collimator plate support member 323 in such a position, the image quality of the high-quality tomographic image can be deteriorated. Therefore, it may be configured so that the collimator plate support members 323 are arranged out of the center position of the X-ray detector in the rotation axis direction. By thus arranging the collimator plate support members 323, the image quality deterioration in a position where a high-quality tomographic image is easily acquired can be prevented. According to the configuration described above, even if the number of detection element arrays increases, the collimator plates 321 can be easily inserted in the grooves 324 of the collimator plate support members 323, which can provide a radiation detector facilitating arrangement of the collimator plates 321 as well as an X-ray CT apparatus equipped with such a radiation detector. Also, by selecting a material of the collimator plate support member 323 properly, output reduction of the X-ray detector due to the collimator plate support members 323 can be reduced. Additionally, image quality deterioration can be prevented by arranging the collimator plate support members 323 in appropriate positions. (Second Embodiment) The second embodiment will be described using FIG. 7. The point different from the first embodiment is that X-ray detection elements have irregular gaps partly in the rotation axis direction (parallel to the Z axis), and the same descriptions will be omitted because the others are the same as the first embodiment. Additionally, FIG. 7 can be substituted for FIG. 4 of the first embodiment. Depending on the material and the number of the collimator plate support members 323, there is a case of lacking the mechanical strength of the collimator plate support members 323 formed thinner than gaps between X-ray detection elements aligned along the rotation axis direction to support the collimator plates 321. In order to supplement the insufficient mechanical strength of the collimator plate support members 323, the thickness of the collimator plate support members 323 should be increased. However, if the collimator plate support members 323 are thicker than the gaps between the X-ray detection elements aligned along the rotation axis direction, the collimator plate support members 323 interfere with the X-ray detection elements, which results in lowering output signals of the X-ray detection elements adjacent to the collimator plate support members 323. Therefore, in the present embodiment, the widths between the X-ray detection elements where the collimator plate support members 323 are arranged are made wider than those between the X-ray detection elements where the collimator plate support members 323 are not arranged so that the collimator plate support members 323 do not interfere with the X-ray detection elements even when the thickness of the collimator plate support members 323 is increased to supplement the insufficient mechanical strength. Specifically, as shown in FIG. 7, the widths between the X-ray detection elements where the collimator plate support members 323 are arranged are expressed as D+δ (δ≠0) while the widths between the X-ray detection elements where the collimator plate support members 323 are not arranged are expressed as D. Additionally, in case of such a configuration, because the X-ray detection elements have irregular gaps partly in the rotation axis direction, the image calculation device 122 performs a process to correct a positional shift in the rotation axis direction for measurement data sent from the data collection device 107 before an inverse projection process is performed. According to the configuration described above, even if the number of detection element arrays increases, the collimator plates 321 can be easily inserted in the grooves 324 of the collimator plate support members 323, which can provide a radiation detector facilitating arrangement of the collimator plates 321 as well as an X-ray CT apparatus equipped with such a radiation detector. Additionally, the radiation detector can be configured without causing insufficient mechanical strength of the collimator plate support members 323. (Third Embodiment) The third embodiment will be described using FIGS. 8 and 9. The point different from the first embodiment is that the pillars 721 and the grooved flat plates 722 are used instead of the grooved pillars 322, and the same descriptions will be omitted because the others are the same as the first embodiment. Additionally, FIG. 8 can be substituted for FIG. 3 of the first embodiment. Also, FIG. 9 is the E-E cross-sectional diagram in FIG. 8 and can be substituted for FIG. 5 of the first embodiment. The pillars 721 support the grooved flat plates 722 and are installed on the substrate 333. The height of the pillars 721 is lower than the height of which the light detection element array 332, the scintillator element array 331, the collimator plate support members 323, and the collimator plate 321 are assembled. The grooved flat plates 722 support the collimator plate 321 from the rotation axis direction and are installed on the upper ends of the pillars 721. The grooved flat plate 722 has the groove 723 to insert the collimator plate 321, and the position of the groove 723 is between X-ray detection elements in the rotation plane (XY plane). The gap between the respective grooves 723 is slightly narrower than that between the grooves 324 provided for the collimator plate support members 323, and the grooves 723 as well as the grooves 324 are provided so that the collimator plates321 are arranged radially toward the X-ray focus 201. The shape of the groove 723 may not be limited unless the shape does not hinder the collimator plates 321 from being arranged radially toward the X-ray focus 201. Also, the collimator plate 321 inserted in the grooves 723 may be fixed by an adhesive. In case of the grooved flat plates 722 having such a structure, a groove process can be simultaneously performed for a plurality of accumulated flat plates, which can reduce the processing cost. Also, in the directions between the X-ray focus 201 and the respective detection elements, the length of the groove 723 of the grooved flat plate 722 is shorter than that of the groove of the grooved pillar 322 in the first embodiment, which can insert the collimator plate 321 easily. According to the configuration described above, even if the number of detection element arrays increases, the collimator plates 321 can be easily inserted in the grooves 324 of the collimator plate support members 323, which can provide a radiation detector facilitating arrangement of the collimator plates 321 as well as an X-ray CT apparatus equipped with such a radiation detector. Additionally, the collimator plates 321 can be easily inserted in the grooves 723 of the grooved flat plate 722. Additionally, the embodiments described above are not for limiting the structure of the present invention but examples showing specific embodiments, and the present invention can be achieved even in the other embodiments having the same effect. For example, although an indirect conversion type of detector in which the scintillator element array 331 and the light detection element array 332 are combined are described in the above embodiments, the present invention can be achieved also by a direct conversion type of detector in which the combination of the scintillator element array 331 and the light detection element array 332 is replaced with a semiconductor element array. Also, although the embodiments are described by taking an X-ray detector as an example, the present invention also includes a radiation detector such as a detector detecting a y ray. Also, although an X-ray tube device is described as an example of a radiation source, a y ray generating source using an isotope may be used. 1: X-ray CT apparatus 100: scan gantry unit 101: X-ray tube device 102: rotating disk 103: collimator 104: opening 105: bed device 106: X-ray detector 107: data collection device 108: gantry controller 109: bed controller 110: X-ray controller 111: high voltage generating device 120: operation console 121: input device 122: image calculation device 123: storage device 124: system controller 125: display device 201: X-ray focus 202: scattered radiation remover 203: detection element module 321: collimator plate 322: grooved pillar 323: collimator plate support member 324: groove 331: scintillator element array 331a: scintillator element 331b: light reflector 332: light detection element array 332a: light detection element 333: substrate 721: pillar 722: grooved flat plate 723: groove
	abstract	A nuclear power plant and method of operation for augmenting a second reactor thermal power output in a second operation cycle to a level larger than a first reactor thermal power output in the previous operation cycle. The plant is equipped, for example, with a reactor; a steam loop comprising high and low pressure turbines; a condenser for condensing steam discharged therefrom the low pressure turbine; a feedwater heater for heating feedwater supplied from the condenser; and a feedwater loop for leading feedwater discharged from the feedwater heater to the reactor. The operation method includes decreasing a ratio of extraction steam which is led to the feedwater heater from a steam loop in the second operation cycle.
	abstract	A nuclear fuel assembly having varying spacing between fuel rods is provided. The nuclear fuel assembly includes a bundle of fuel rods. The fuel rods are arranged in a first lattice with a non-uniform pitch between the fuel rods in the lowermost section of the fuel assembly and in a second lattice with a uniform pitch between the fuel rods in the uppermost section of the fuel assembly.
	abstract	A device containment apparatus includes a vessel for storing an explosive device and minimizing dispersal of radioactive material. The vessel includes an outer wall defining an interior area. A first frame supports the vessel and supports a first or outer radiation shield that is spaced from the vessel. A second or inner radiation shield can also be provided, supported adjacent the vessel's outer wall by a second frame that includes upper and lower frame rings. The vessel and the second radiation shield can be generally spherical, while the first frame is substantially rectangular, and the first radiation shield includes substantially planar sides.
044341334	claims	1. A process of converting inorganic carbonate mineral material to organic hydrocarbon material, comprising the steps of: (1) reacting inorganic carbonate mineral material with a stoichiometric excess of molten lithium metal, at a temperature over about 300.degree. C. in the absence of air and moisture, to produce a product mixture comprising lithium salts Li.sub.2 C.sub.2 and Li.sub.2 O, and then (2) hydrolyzing the lithium salts produced in step (1), to produce C.sub.2 H.sub.2, and then (3) catalytically reacting the C.sub.2 H.sub.2 produced in step (2), with steam, in the presence of zinc containing catalyst, in a manner effective to produce CH.sub.3 COCH.sub.3, and then (4) pyrolyzing the CH.sub.3 COCH.sub.3 produced in step (3), to provide ketene and methane, and then (5) separating ketene from methane. (1) reacting inorganic carbonate mineral material with a stoichiometric excess of molten lithium metal, at a temperature over about 300.degree. C. in the absence of air and moisture, to produce a product mixture comprising lithium salts Li.sub.2 C.sub.2 and Li.sub.2 O, and then (2) hydrolyzing the lithium salts produced in step (1), to produce C.sub.2 H.sub.2, and then (3) catalytically reacting the C.sub.2 H.sub.2 produced in step (2), with steam, in the presence of zinc containing catalyst, at between about 250.degree. C. and about 475.degree. C., in a manner effective to provide gases which upon condensation yield CH.sub.3 COCH.sub.3, without producing benzene, and then (4) pyrolyzing the CH.sub.3 COCH.sub.3 produced in step (3), at between about 600.degree. C. and about 800.degree. C., to provide ketene and methane, and then (5) separting ketene from methane, and then (6) decomposing the ketene to provide methylene, and then (7) reacting the methylene with an alkane material, to provide a product which is reacted with additional methylene in a manner effective to cause methylene insertion chain reactions and provide hydrocarbon materials containing at least three carbon atoms; where at least a part of the heat energy required for the pyrolyzing step of step (4) is supplied from a nuclear reactor. 2. The method of claim 1, where during the hydrolysis step (2), LiOH is also produced, and said LiOH is reacted to form lithium chloride, which is then electrolyzed to provide Li metal which is recycled back to step (1). 3. The method of claim 2, where the heat energy required for the pyrolyzing step to form ketene, and the electrolyzing step to form Li metal is supplied, at least in part, from a nuclear reactor. 4. The method of claim 2, where the catalyst used in step (3) is selected from the group consisting of zinc oxide, zinc vanadate, and mixtures thereof, where benzene is not produced in step (3), and the reaction in step (3) proceeds at between about 250.degree. C. and about 475.degree. C. 5. The method of claim 2, where after step (5), the ketene is decomposed to provide methylene. 6. A process of converting inorganic carbonate mineral material to organic high carbon chain hydrocarbon material, utilizing nuclear reactor energy, comprising the steps of: 7. The method of claim 6, where the carbonate mineral material is selected from the group consisting of calcite, dolomite, siderite, magnesite, rhodochrosite, smithsonite, arajonite, witherite, strontianite, cerussite, malachite, azurite, and mixtures thereof. 8. The method of claim 6, where during the hydrolysis step (2), LiOH is also produced, and said LiOH is reacted to form lithium chloride which is then electrolyzed to provide Li metal which is recycled back to step (1). 9. The method of claim 6, where the catalyst used in step (3) is selected from the group consisting of zinc oxide, zinc vanadate, and mixtures thereof, and the carbonate mineral material is limestone. 10. The method of claim 6, where ketene is separated from methane in step (5) by condensing ketene at about -60.degree. C., after which it is allowed to vaporize. 11. The method of claim 6, where the ketene after step (5) is in vapor form, and is decomposed in step (6) by heat and/or light energy. 12. The method of claim 6, where the alkane reacting with methylene in step (7) is methane supplied at least in part from step (4), and where the methane reacts with methylene to form ethane, the ethane reacts with methylene to form propane, and the propane reacts with methylene to form butane; said methane being fed into a long tube reactor having a plurality of spaced apart downstream methylene inlets. 13. The method of claim 6, where the nuclear reactor utilized is liquid-cooled nuclear reactor. 14. The method of claim 8, where the energy required for the electrolyzing step to form Li metal, is supplied in part from a nuclear reactor.
	abstract	A magnetic jack type control element drive mechanism for precision position control of a control element assembly, satisfies the following conditions:D1=D2=P+D5;D3=P×2;D4=D3×(N−½), (N is an arbitrary natural number), wherein D1 represents a lift gap of the upper motor assembly; D2 represents a lift gap of the lower motor assembly; D3 represents a space width between tips of adjacent teeth of the drive shaft; D4 represents a gap between an upper latch and a lower latch; P represents pitch that is a distance of ascent or descent of the drive shaft; and D5 represents a margin which is a separation space between the teeth and the upper latch or the lower latch when the upper latch or the lower latch is inserted into the teeth of the drive shaft.
046706585	claims	1. A protective sheet useful for radiological procedures, comprising: a support matrix and a radio-opaque portion of barium sulfate supported by said matrix, said radio-opaque portion being present in an amount sufficient to block a substantial amount of the scatter radiation. 2. The sheet of claim 1 wherein said support portion is gauze and wherein said barium sulfate is supported in said gauze by soaking said gauze in a barium sulfate suspension and then evaporating the water therefrom. 3. The sheet of claim 1 further comprising: a base and a cover, said base being attached to and positioned on one side of said support matrix and said cover being attached to and positioned on the other side of said support matrix. 4. The sheet of claim 2 further comprising: a base and a cover, said base being attached to and positioned on one side of said support matrix and said cover being attached to and positioned on the other side of said support matrix. 5. The sheet of claim 3 wherein said base is a thin impermeable ply. 6. The sheet of claim 4 wherein said base is a thin impermeable ply. 7. The sheet of claim 3 wherein said cover is a surgical drape. 8. The sheet of claim 4 wherein said cover is a surgical drape. 9. The sheet of claim 1 wherein between 350 to 730 grams of barium sulfate powder is evenly distributed in each square foot of said support matrix. 10. The sheet of claim 3 wherein between 350 to 730 grams of barium sulfate powder is evenly distributed in each square foot of said support matrix. 11. The sheet of claim 3 wherein said sheet is at least two square feet in area. 12. The sheet of claim 3 wherein said sheet is between one-half to one inch thick. 13. A protective laminate for reducing exposure to scatter radiation generated during radiological procedures, the laminate comprising: a thin impermeable base ply, a radio-opaque ply attached to and positioned on said base ply, said radio-opaque ply including a support matrix and a radio-opaque compound supported by said matrix, said radio-opaque compound being present in an amount sufficient to block a substantial amount of the scatter radiation, and an upper ply of absorbent material attached to and positioned on said radio-opaque ply. 14. The laminate of claim 13 wherein said radio-opaque ply is impregnated with barium sulfate powder. 15. The laminate of claim 14 wherein between 350 to 730 grams of said barium sulfate powder is distributed in each square foot of said support matrix.
044302568	claims	1. A nuclear waste package comprising any material containing a radionuclide and a surrounding overpack or backfill containing a non-radioactive compound of the element or analogue of the element of the radionuclide or a natural or synthetic mineral containing an actinide which provides a greater concentration of ions of the non-radioactive elements than are provided by the radionuclides. 2. A nuclear waste package according to claim 1 wherein the radionuclide comprises Cs, Sr, I, Tc, or actinide element and the overpack or backfill contains a non-radioactive element which is Cs, Sr, I, Mn, or lanthanide element. 3. A nuclear waste package according to claim 2 wherein the radionuclide comprises radioactive Cs and the non-radioactive element comprises Cs. 4. A nuclear waste package according to claim 2 wherein the radionuclide comprises radioactive Sr and the non-radioactive element comprises Sr. 5. A nuclear waste package according to claim 2 wherein the radionuclide comprises a radioactive actinide element and the non-radioactive element comprises a lanthanide element. 6. A nuclear waste package according to claim 1 wherein there is employed in the overpack or backfill a form of the non-radioactive element or actinide which is only slightly more soluble than the radioactive waste form of the element in the repository fluid. 7. A nuclear waste package according to claim 6 wherein the radionuclide comprises Cs, Sr, I, Tc, or actinide element and the overpack or backfill contains a non-radioactive element which is Cs, Sr, I, Mn, or lanthanide element. 8. A nuclear waste package according to claim 7 wherein the overpack or backfill material comprises a mineral or ceramic material containing said non-radioactive element or actinide in the form of a compound. 9. A nuclear waste package according to claim 8 wherein the radioactive element is Cs and the overpack or backfill contains the non-radioactive element in the form of a compound of Cs with at least one of Al.sub.2 O.sub.3, SiO.sub.2, P.sub.2 O.sub.5, and TiO.sub.2. 10. A nuclear waste package according to claim 8 wherein the radioactive element is Sr and the overpack or backfill contains the non-radioactive element in the form of a compound of Sr with at least one of Al.sub.2 O.sub.3, SiO.sub.2, and P.sub.2 O.sub.5. 11. A nuclear waste package according to claim 8 wherein the radioactive element is an actinide with the overpack or backfill contains a non-radioactive element which is a lanthanide element in the form of a lanthanide oxide or compound of a lanthanide oxide with at least one of Al.sub.2 O.sub.3, SiO.sub.2, and P.sub.2 O.sub.5. 12. A nuclear waste package according to claim 1 wherein the overpack or backfill is present as a tamped in mineral containing ion-dopant of the non-radioactive element. 13. A nuclear waste package according to claim 1 wherein the overpack or backfill is present as ceramic briquettes of containing ion-dopant of the non-radioactive element or actinide containing mineral surrounding an inner layer of overpack or backfill. 14. A nuclear waste package according to claim 13 containing additional overpack or backfill outside the briquettes. 15. A nuclear waste package according to claim 1 wherein the non-radioactive element or actinide containing mineral is present in various ion concentrations dispersed through the overpack or backfill. 16. A nuclear waste package according to claim 2 having a reverse thermodynamic chemical gradient of non-radioactive Cs, Sr, lanthanide, I, or Mn in an amount between 0.1 and 100.times. the total contained amount of the ion contained in the waste form in an insoluble overpack or backfill material. 17. A package according to claim 16 wherein the non-radioactive concentration is over 1.times.. 18. A process for constructing a reverse thermodynamic barrier comprising surrounding the nuclear waste form of claim 1 in a repository with a mineral overpack or backfill containing the non-radioactive element or actinide containing mineral in compound form. 19. A process according to claim 18 comprising tamping in a mixture of the mineral and an ion-dopant of the non-radioactive element or actinide mineral around the nuclear waste package. 20. A process according to claim 18 comprising surrounding a layer of overpack with ceramic briquettes ion-doped with a compound of the non-radioactive element. 21. A process according to claim 20 including the step of placing additional overpack or backfill around the briquettes. 22. A process according to claim 1 wherein the overpack or backfill contains 0.1 to 100.times. the total amount of ion contained in the radioactive waste form.
	abstract	A processes for recycling uranium that has been used for the production of molybdenum-99 involves irradiating a solution of uranium suitable for forming fission products including molybdenum-99, conditioning the irradiated solution to one suitable for inducing the formation of crystals of uranyl nitrate hydrates, then forming the crystals and a supernatant and then separating the crystals from the supernatant, thus using the crystals as a source of uranium for recycle. Molybdenum-99 is recovered from the supernatant using an adsorbent such as alumina. Another process involves irradiation of a solid target comprising uranium, forming an acidic solution from the irradiated target suitable for inducing the formation of crystals of uranyl nitrate hydrates, then forming the crystals and a supernatant and then separating the crystals from the supernatant, thus using the crystals as a source of uranium for recycle. Molybdenum-99 is recovered from the supernatant using an adsorbent such as alumina.
	abstract	An x-ray generation apparatus includes an x-ray reflecting mirror and x-ray generation part. The x-ray reflecting mirror is formed on an inner surface of a concave aspheric surface. The x-ray generation part receives at least one incident energy beam. The x-ray generation part is arranged near a focal point including a focal point of a paraboloid, and the x-ray reflecting mirror has at least one aperture formed in a position except for a part of the concave aspheric surface crossing an axis including the focal point of the concave aspheric surface, and an incident energy beam irradiates the x-ray generation part through the aperture.
	description	This application claims the benefit of Korean Patent Application No. 2005-6443, filed Jan. 24, 2005, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference. 1. Field of the Invention The present general inventive concept relates to a thin film transistor (TFT) array inspecting apparatus, and more particularly, to a TFT array inspecting apparatus which inspects a TFT array disposed at an inclined position so that TFT arrays having different sizes are continuously inspected, and allows an electron detecting unit to be disposed close to the TFT array so that secondary electron detecting performance is improved. 2. Description of the Related Art A thin film transistor liquid crystal display (TFT-LCD), which is a type of a flat display panel device, is a device for displaying data using characteristics of liquid crystal, in which transmittancy of light is changed according to a voltage, is operable at a low voltage, and has a low power consumption rate, thereby being increasingly used in office automation (OA) equipment and household electric appliances. Generally, the above TFT-LCD comprises a lower glass substrate on which arrays of TFTs serving as individual switching elements are installed, an upper glass substrate on which three color filters, i.e., red, green, and blue filters, are formed, a liquid crystal injected into a space between the lower glass substrate and the upper glass substrate, and a back light for supplying light emitted from an area below the lower glass substrate. The TFT-LCD varies a molecular structure according to electrical signals of the TFTs and a voltage applied to an LCD, and controls a degree of transmittance of the light. Then, the TFT-LCD causes the controlled light to pass through the three color filters, thus displaying desired color and image. The above TFT-LCD is manufactured through an array manufacturing process in which the TFTs are formed, a cell manufacturing process in which the liquid crystal between a TFT array substrate (lower glass substrate) and a color filter substrate (upper glass substrate) is sealed, and a module manufacturing process in which an electric circuit for driving a TFT array substrate and a cell substrate is mounted. After the TFT array is manufactured, it is inspected to determine whether or not the TFT array is defective. U.S. Pat. No. 6,075,245 discloses a TFT array inspecting apparatus. The above TFT array inspecting apparatus comprises a CRT gun installed at an upper part of a vacuum chamber for emitting electron beam, a vacuum pump installed under the vacuum chamber for vacuuming an inside of the vacuum chamber, and an electric detector installed at one side of the vacuum chamber for detecting electrons emitted from a TFT array using the electron beam to inspect the TFT array disposed in the vacuum chamber. The above conventional TFT array inspecting apparatus has a limitation in inspecting TFT arrays having various sizes in a single vacuum chamber. That is, a projection range of the CRT gun is set to a predetermined value according to the TFT array having a designated size, the TFT array inspecting apparatus cannot inspect TFT arrays having sizes larger than the set projection range of the CRT gun. Accordingly, in order to inspect TFT arrays having sizes lager than the set projection range of the CRT gun, the projection range of the CRT gun is reset, and then the inside of the vacuum chamber is again vacuumed to a required vacuum degree. Thus, inspection of the TFT arrays having various sizes in a single chamber has a complicated procedure and requires a long period of time for preparing the complicated procedure. In order to solve the foregoing and/or other problems, the present general inventive concept provides a TFT array inspecting apparatus which inspects a TFT array located at either an inclined position or a level position. The present general inventive concept provides a TFT array inspecting apparatus which detects secondary electrons when an electron detecting unit is located adjacent to a TFT array to be inspected. Additional aspects and advantages of the present general inventive concept 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 general inventive concept. The foregoing and/or other aspects and advantages of the present general inventive concept may be achieved by providing a TFT array inspecting apparatus comprising a vacuum chamber, a stage disposed in the vacuum chamber so that a TFT array to be inspected is disposed on the stage, an electron gun disposed opposite to the stage in the vacuum chamber to generate an electron beam onto the TFT array, an electron detecting unit to detect secondary electrons emitted from the TFT array by the electron gun, and at least one elevating unit to move the TFT array at a designated angle between a level position and an inclined position. The electron gun may be disposed above the vacuum chamber, the stage may be disposed at a lower part of the vacuum chamber, and the elevating unit may be disposed at a first end of the stage. A stopper protruding upwardly may be provided at a second end of the stage, and the TFT array is moved to the inclined position by lifting a first end of the TFT array using the elevating unit while a second end of the TFT array is caught by the stopper. The elevating unit may be a hydraulic cylinder type. The electron detecting unit may vertically be installed above the stopper to detect the secondary electrons emitted from the TFT array. A lens unit to set an irradiating position of the electron beam and a deflection unit to deflect the electron beam passing through the lens unit are disposed in front of the electron gun. The foregoing and/or other aspects and advantages of the present general inventive concept may also be achieved by providing a TFT array inspecting apparatus comprising a vacuum chamber vacuumed by a vacuum pump, an electron gun to generate an electron beam onto a TFT array disposed in the vacuum chamber, an electron detecting unit to detect secondary electrons emitted from the TFT array by the electron beam, and at least one elevating unit to move the TFT array between a level position and an inclined position having a designated angle with the level position. The electron gun may be disposed above the vacuum chamber, the TFT array may be disposed at a lower part of the vacuum chamber, and the elevating unit may be disposed at a first end of the TFT array to elevate the end of the TFT array. The electron detecting unit is vertically installed above a second end of the TFT array to detect the secondary electrons emitted from the TFT array. Reference will now be made in detail to the embodiment of the present general inventive concept, an example of which is illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. The embodiment is described below to explain the present invention by referring to the annexed drawings. FIG. 1 is a schematic block diagram illustrating a TFT array inspecting apparatus according to an embodiment of the present general inventive concept. As shown in FIG. 1, the TFT array inspecting apparatus comprises a vacuum chamber 10, a vacuum pump 20 installed under the vacuum chamber 10 to vacuum an inside of the vacuum chamber 10, an electron gun 30 disposed above the vacuum chamber 10, a lens unit 31 and a deflection unit 32 disposed in front of the electron gun 30, a stage 40 installed on a bottom surface of the inside of the vacuum chamber 10 to mount a TFT array 1 thereon to be inspected, a pair of elevating units 50 installed under the vacuum chamber 10, and an electron detecting unit 60 disposed at one side of the vacuum chamber 10. The electron gun 30 has a structure which generates an electron beam 33 (with reference to FIG. 2) having a high energy level to inspect whether or not the TFT array 1 is defective in a vacuum state, and the lens unit 31 has a structure which adjusts a direction and an intensity of the electron beam 33 emitted from the electron gun 30. Further, the deflection unit 32 installed in front of the lens unit 31 has a structure which deflects the electron beam 33, passing through the lens unit 31, towards respective pixels 2 of the TFT array 1 so that an overall surface of the TFT array 1 to be inspected is continuously scanned. The stage 40 has a flat shape with a size lager than that of the TFT array 1 to mount the TFT array 1 thereon in the vacuum chamber 10, and is disposed on the bottom of the vacuum chamber 10. Each of the pair of the elevating units 50 includes a hydraulic cylinder having a main body 51 and a piston rod 52 vertically moving along the main body 51. The elevating units 50 are vertically disposed on a lower surface of a first end 41 of the stage 40, and vertically move a first end of the TFT array 1. Although FIG. 1 illustrates two elevating units 50 in a pair, the number of the elevating units 50 may be increased or decreased according to the size of the TFT array 1 to be inspected. For example, in a case that the TFT array 1 has a small size, only one elevating unit 50 may be prepared, and in a case that the TFT array 1 has a large size, at least three elevating units 50 may be prepared. The main bodies 51 of the elevating units 50 may be disposed below an outside of the vacuum chamber 10, and the piston rods 52 of the elevating units 50 may vertically move between insides of the main bodies 51 and the inside of the vacuum chamber 10. In order to allow the piston rods 52 of the elevating units 50 to vertically move the TFT array 1 disposed on an upper surface of the stage 40, a pair of through holes 43 through which the piston rods 52 of the elevating units 50 pass are formed on the first end 41 of the stage 40. In order to fix the second end of the TFT array 1 without a movement when the piston rods 52 lift the first end of the TFT array 1, a stopper 44 extended from the upper surface of the stage 40 is installed at a second end 42 of the stage 40. Accordingly, when the piston rods 52 move upwardly or downwardly, the first end of the TFT array 1 is elevated upwardly or lowered downwardly under a condition that a second end of the TFT array 1 contacting the stopper 44 is fixed to the stage 40. Thereby, it is possible to move the TFT array 1 from a level position to an inclined position, from the inclined position to the level position, or a position between the level position and the inclined position. Although FIG. 1 illustrates a length of the stopper 44 is the same as a longitudinal length of the stage 40, the stopper 44 may be extended from both end of the stage 40 such that the length of the stopper 44 is larger than the longitudinal length of the stage 40 so long as the TFT array 1 is fixed to the stopper 44. The electron detecting unit 60 is disposed above the stopper 44 such that the electron detecting unit 60 is approximately vertical to the surface of the stage 40, and detects electrons emitted from the TFT array 1 using the electron beam 33 when the TFT array 1 is disposed at the level position or the most inclined position. The electron beam 33 emitted from the electron gun 30 may be a primary electron, and the electron emitted from the TFT array 1 in response to the electron beam 33 may be a secondary electron. Hereinafter, a process of inspecting a TFT array disposed at an inclined position using the above TFT array inspecting apparatus of FIG. 1 according to an embodiment of the present general inventive concept will be described. As shown in FIG. 2, when the TFT array 1 having a size, which can not be inspected at its level position by the electron beam 33 emitted by the electron gun 30 through the lens unit 31 and the deflection unit 32, is disposed on the stage 40 in the vacuum chamber 10, the elevating units 50 are operated to lift the first end of the TFT array 1 to the inclined angle such that the electron beam 30 emitted from the electron gun 33 is irradiated onto an overall inspected area of the TFT array 1. Thereafter, when the electron beam 33 is emitted from the electron gun 30 and passes through the lens unit 31, the direction and the intensity of the electron beam 33 are adjusted. Then, when the electron beam 33 passes through the deflection unit 32, the electron beam 33 is deflected and is irradiated sequentially onto the pixels 2 of the TFT array 1, thereby scanning the TFT array 1. When the electron beam 33 collides with the pixels 2, the secondary electrons are generated from the pixels 2 and transmitted to the electron detecting unit 60. The electron detecting unit 60 measures a route and the intensity of the electron beam 33 moving to the pixels 2 and an intensity of the secondary electrons transmitted from the pixels 2, thereby detecting whether or not the TFT array 1 defective. Accordingly, since the electron detecting unit 60 detecting the secondary electrons generated from the TFT array 1 is located at a position close to the TFT array 1, the electron detecting unit 60 has an improved detection performance. The electron gun 30 of the TFT array inspecting apparatus is vertically disposed above the first end of the TFT array 1, and the TFT array inspecting apparatus inspects the TFT array 1 disposed at the inclined position toward the electron detecting unit 60, thus allowing the electron detecting unit 60 to precisely detect the intensity of the secondary electrons. Hereinafter, it will be described that a TFT array having a comparatively large size is inspected when the TFT array is inspected when the TFT array is disposed at an inclined position having an angle with a level position. As shown in FIGS. 1-3, when a first TFT array la having a first inspection length the same as or smaller than an effective inspection length (L1) of the TFT array inspecting apparatus of the present general inventive concept is inspected, the first TFT array 1a is inspected when the TFT array 1a is disposed at a level position on the stage 40 in the same manner as a conventional TFT array. When a second TFT array 1b having a second inspection length (L2) larger than the effective inspection length (L1) of the TFT array inspecting apparatus of the present general inventive concept is disposed in the vacuum chamber 10 after the inspection of the first TFT array 1a is completed, the elevating units 50 lift a first end of the second TFT array 1b to a designated angle (θ1). Thereby, the second inspection length (L2) of the TFT array 1b at the inclined position is within a range of the effective inspection length (L1). When the second TFT array 1b inclined at the angle (θ1) is inspected, it is possible to inspect the second TFT array 1b having the second inspection length (L2) larger than the effective inspection length (L1). When a third TFT array 1c having a third inspection length (L3) larger than the second inspection length (L2) of the second TFT array 1b is disposed in the vacuum chamber 10, the elevating units 50 lift a first end of the third TFT array 1c to a designated angle (θ2) higher than the angle (θ1) of the second TFT array 1b so that the third inspection length (L3) of the third TFT array 1c at the inclined position is in the range of the effective inspection length (L1). Accordingly, it is possible to inspect the third TFT array 1c having the third inspection length (L3) larger than the inspection lengths (L1) and (L2) of the first and second TFT arrays 1a and 1b. As described above, the TFT array inspecting apparatus of the present general inventive concept inspects whether or not the first, second, and third TFT arrays 1a, 1b, and 1c having different sizes are defective by simply moving the first, second, and third TFT arrays 1a, 1b, and 1c to a position between the level position and the inclined position. Accordingly, in a case that the TFT arrays have slightly different sizes, the TFT array inspecting apparatus of the present general inventive concept rapidly and simply inspects whether or not these TFT arrays are defective. As apparent from the above description, the present general inventive concept provides a TFT array inspecting apparatus which inspects whether or not a TFT array disposed at either an inclined position or a level position is defective, thereby being capable of rapidly and simply inspecting TFT arrays having different sizes in a single vacuum chamber. Further, the TFT array inspecting apparatus of the present general inventive concept comprises an electron detecting unit to detect secondary electrons when the electron detecting unit is located close to the TFT array, thereby improving a secondary electron-detecting performance and precisely inspecting a failure of the TFT array. Although an embodiment of the general inventive concept has been shown and described, it would be appreciated by those skilled in the art that changes may be made in this embodiment without departing from the principles and spirit of the general inventive concept, the scope of which is defined in the claims and their equivalents.
	abstract	In some embodiments, a system includes a set of moulding sections, at least one electrical conductor affixed at least partially within one or more of the set of moulding sections, and one or more joints between various ones of the set of moulding sections. At least some of the one or more joints are arranged to preserve electrical conductivity, via the at least one electrical conductor, between the various ones of the set of moulding sections.
	description	This application claims priority to United Kingdom Application GB0721531.2, filed Nov. 2, 2007, which is hereby incorporated by reference. Not Applicable. This invention relates to mounting arrangements for one or more electrodes onto a support member. More particularly the invention relates to such mounting arrangements that compensate for thermal coefficient differences between both the electrode and the support member. The invention has particular application in mass spectrometry, and more particular to the provision of a miniature quadrupole mass filter, a linear quadrupole ion trap or a quadrupole ion-guide with a high tolerance of temperature variations. Miniature mass spectrometers have application as portable devices for the detection of biological and chemical warfare agents, drugs, explosives and pollutants, as instruments for space exploration, and as residual gas analysers. Further applications exist for low cost systems in pharmaceutical analysis. Mass spectrometers consist of three main subsystems: an ion source, an ion filter, and an ion counter. One of the most successful variants is the quadrupole mass spectrometer, which uses an electrostatic quadrupole as a mass-filter [Paul 1953]. Conventional quadrupoles consist of four cylindrical electrodes, which are mounted parallel and with their centre-to-centre spacing at a well-defined ratio to their diameter [Dawson 1976; Denison 1971]. Ions are injected into the pupil between the electrodes, and travel parallel to the electrodes under the influence of a time-varying field approximating an ideal hyperbolic potential variation. This field contains both a direct current (DC) and an alternating current (AC) component. The frequency of the AC component is fixed, and the ratio of the DC voltage to the AC voltage is also fixed. Studies of the dynamics of an ion in such a field have shown that only those ions with a particular charge to mass ratio will transit the quadrupole without discharging against one of the rods. Consequently, the device acts as a mass filter. The ions that successfully exit the filter may be detected. If the DC and AC voltages are ramped together, the detected signal is a spectrum of the different masses that are present in the ion flux. The largest mass that can be detected is determined from the largest voltage that can be applied. If the DC component is omitted, and the quadrupole is operated in RF-only mode, the action of the field is different, and the quadrupole acts as an all-pass filter or ion guide [Dawson 1985; Miller 1986]. When ion transmission is interrupted by collisions with other ions or neutrals, a form of ion focusing known as collision focusing takes place. As a result quadrupole ion guides have a variety of applications in mass spectrometers, including devices for enhancement of transmission and devices for ion fragmentation known as collision cells [Douglas 1998]. An electrostatic quadrupole may also be used in an alternative form of mass spectrometer known as a linear quadrupole ion trap [Prestage 1989]. If suitable barrier potentials are provided using additional electrodes at the ends of the quadrupole, ions may be confined inside the quadrupole and perform multiple transits up and down its axis. Ions may be mass selectively ejected from the exit by a variety of means including using an auxiliary AC voltage applied to the end electrode, at the same time as ions are admitted at the entrance [Hager 1989; U.S. Pat. No. 6,177,668]. Improved filter performance follows from the increased number of RF cycles experienced by the ions and increased signal-to-noise ratio follows from the accumulation of ions inside the trap. A linear ion trap may also be operated using time gating of the end potentials [Campbell 1998]. The resolution quadrupole filter is determined by two main factors: the number of cycles of alternating voltage experienced by each ion, and the accuracy with which the desired field is created. So that each ion experiences a large enough number of cycles, the ions are injected with a small axial velocity, and a radio frequency AC component is used. The accuracy with which the field is created is determined by the shape and size of the electrodes, and by their placement and their straightness. Numerous studies have shown that a good approximation to a hyperbolic field is provided by cylindrical electrodes with their centre-to-centre spacing at a well-defined ratio to their diameter. However, a reduction in the mass resolution is caused by misplacement of the electrodes [Dawson 1979], by bending of the electrodes [Dawson 1988] or by other distortions of the field. To avoid such problems, highly accurate methods of construction are employed. However, it becomes increasingly difficult to obtain the required precision as the size of the structure is reduced. Microfabrication methods are therefore increasingly being used to miniaturise mass spectrometers, both to reduce costs and allow portability. These processes are generally carried out on planar substrates, which are often silicon or multilayers containing silicon. The most important of the processes considered here include: Patterning methods such as photolithography; Etching methods such as deep reactive ion etching of silicon; Bonding methods such as anodic bonding of silicon and direct bonding of silicon; Isolation methods such as oxidation of silicon; Coating methods such as sputtering of metals; Interconnection methods such as thermocompression bonding of gold wire. These methods are well known to those skilled in the art, and can be employed in many different combinations to achieve a given microstructured object. For example, a miniature silicon-based quadrupole electrostatic mass filter consisting of four cylindrical electrodes mounted in pairs on two oxidised silicon substrates was demonstrated some years ago. The substrates were held apart by two cylindrical insulating spacers, and V-shaped grooves formed by anisotropic wet chemical etching were used to locate the electrodes and the spacers. The electrodes were metal-coated glass rods soldered to metal films deposited in the grooves [U.S. Pat. No. 6,025,591]. Mass filtering was demonstrated using devices with electrodes of 0.5 mm diameter and 30 mm length [Syms et al. 1996; Syms et al. 1998; Taylor et al. 1999]. Performance was limited by RF heating, caused by electrical coupling between co-planar cylindrical electrodes through the oxide interlayer via the substrate. As a result, the device presented a poor electrical load, the solder attaching the cylindrical electrodes tended to melt, and differences in expansion coefficient between the cylindrical electrodes and the substrate caused the electrodes to detach. These effects restricted the voltage and frequency that could be used, which in turn limited the mass range (to around 100 atomic mass units) and the resolution. In an effort to overcome these limitations, an alternative miniature construction based on bonded silicon-on-insulator (BSOI) was developed [GB 2391694]. BSOI consists of an oxidised silicon wafer, to which a second silicon wafer has been bonded. The second wafer may be polished back to the desired thickness, to leave a silicon-oxide-silicon multi-layer. In this geometry, cylindrical stainless steel electrodes were mounted in pairs on two substrates. The oxide interlayer was largely removed, so that electrical coupling between co-planar cylindrical electrodes via the substrate was greatly reduced. As a result, the device could withstand considerably higher voltages, and a mass range of 400 atomic mass units was demonstrated [Geear 2005]. The cylindrical electrodes were retained by the pressure contact of two silicon springs etched into the substrate of the BSOI wafer. The spring retaining system allowed a sliding motion of the electrodes, so that variations in temperature did not cause strains due to differences in the thermal expansion coefficients of the stainless steel cylindrical electrodes and the silicon mount. However, the sliding motion allowed the position of the electrodes to alter slightly, either over long periods of time or following mechanical shocks, degrading the constructional accuracy of the filter. There is therefore a benefit in rigidly retaining the electrodes on the supporting substrates but there are still problems regarding differences in thermal expansion coefficients between the electrodes and their respective mounts. Accordingly there is a need for a mounting arrangement for an electrode onto a support member that compensates for thermal coefficient differences between both the electrode and the support member. Such a mounting arrangement is particularly useful in provision of a mounting for a miniature quadrupole mass filter, linear quadrupole ion trap or quadrupole ion guide, in which good electrical performance is combined with mechanical insensitivity to temperature variations. Accordingly the invention provides a mounting arrangement according to claim 1. Advantageous embodiments are provided in the claims dependent thereto. The invention also provides a mount according to claims 13 or 19 with advantageous embodiments provided in the claims dependent thereto. These and other features will be better understood with reference to the following drawings. A mounting arrangement for at least one electrode will now be described with reference to an exemplary application thereof, that of achieving alignment of sets of cylindrical metal electrodes in a geometry of a miniature electrostatic quadrupole. Use of such a mounting arrangement is particularly advantageous within the context of the teaching of our earlier application GB0701809.6, which shows methods of aligning sets of cylindrical metal electrodes in the geometry of a miniature electrostatic quadrupole, which can act as a quadrupole mass filter, a linear quadrupole ion trap or a quadrupole ion guide. In that arrangement, the electrodes are mounted in two pairs on two microfabricated supports, which are formed from conducting parts on an insulating substrate. Using the teaching of the present invention it is possible to provide the supports, which were previously described in GB0701809.6 as rigid supports, in the form of a suspended flexure system to relieve thermal strains caused by mismatch between the expansion coefficients of the cylindrical electrodes and their mountings. A complete quadrupole may be constructed from two such insulating substrates, which are held apart by further conducting spacers. The construction of the mount can be better understood with reference to FIGS. 1-7, which is provided as an illustrative example of how a mounting arrangement provided in accordance with the teaching of the invention may be usefully employed. It will therefore be appreciated that while this exemplary arrangement is in the provision of a quadrupole that a mounting invention provided in accordance with the teaching of the invention is not to be considered as being limited to such applications. FIG. 1 shows the layout, in plan, of one of the two cylindrical electrode mounts, which consists of a set of parts or support members formed on an insulating substrate 100, which may be provided in accordance with the teaching of the invention. The parts are desirably conducting or coated with a conducting layer. In this exemplary arrangement, a pair of flexible supports 101a, 101b are provided at one end of the substrate, and a pair of rigid supports 102a, 102b are provided at the other end. The two flexible supports 101a and 101b and the two rigid supports 102a, 102b are separated by central gaps 103 and 104, i.e. they are physically distinct from one another. The four supports 101a, 101b and 102a, 102b are further separated from a central feature 105 by gaps 106a, 106b. Each of the flexible support 101a and the rigid support 102a provide locating features 107a and 108a for the two ends of a first cylindrical electrode 109a, in this exemplary arrangement the opposing two ends. Similarly, the flexible support 101b and the rigid support 102b provide locating features 107b and 108b for the two ends of a second cylindrical electrode 109b. The central feature 105 contains a trench 110 along its length, and the gaps 103, 104, 106a, 106b provide electrical isolation between the parts. FIG. 2 shows the layout in sections of the part shown in FIG. 1. The two rigid electrode supports 102a, 102b in section A-A′ consist of two blocks of material that are fixed to the substrate 100 along their entire length. The rigid electrode supports 102a, 102b support one end of the two cylindrical electrodes 109a, 109b in locating features 108a, 108b. The two flexible supports 101a, 101b in section B-B′ consist of two blocks of material that are fixed to the substrate 100 only along part of their length at lands 201a, 201b. In other regions 202a, 202b the flexible supports are suspended above the substrate 100 by clearances 203a, 203b. The suspension of the flexible supports allows relative movement along at least a portion of the length of the flexible support to the substrate. It will be understood that the flexible supports have a fixed end which is physically fixed to the substrate 100 and a second end, distally located from that fixed end, which is capable of moving relative to the substrate. The flexible electrode supports 101a, 101b support the other end of the two cylindrical electrodes 109a, 109b in locating features 107a, 107b, which are typically (as shown in FIG. 2) located at this second end of the flexible supports. The cylindrical electrodes 109a, 109b in section C-C′ lie parallel to one another within the trench 110 in the feature 105. The walls of the trench 110 do not contact the cylindrical electrodes, but provide a partial surrounding shield. The cylindrical electrodes may be attached to their supports in the regions 204a, 204b, 205a, 205b by a variety of methods including the use of conducting epoxy and solder. Although the cylindrical electrodes are therefore rigidly fixed to their supports, the suspended parts 202a, 202b are free to move parallel to the substrate plane if formed in a suitable material and arrangement. Consequently it will be appreciated that motion of the two suspended parts 202a, 202b in the plane of the substrate and parallel to the axis of the cylindrical electrodes can relieve an axial strain due to a mismatch in thermal expansion coefficient between the cylindrical electrodes and their mounting. It will also be appreciated that by fixing the same ends of the pair of cylindrical electrodes to the substrate, axial alignment between the electrodes is preserved in the process. An example of a suitable elastic support for each cylindrical electrode may be provided by a portal frame suspension. A portal frame is a simple arrangement of elastic elements that combines controllable linear stiffness in one direction (the in-plane direction) with high stiffness in the perpendicular direction (the out-of-plane direction). Portal frames are commonly used in microfabricated devices to provide approximately linear motion such as that described in Tang 1989. However it will be understood that it is not intended to limit the present invention to this exemplary arrangement as other forms of suspended elastic element may suffice to provide thermal coefficient compensation. FIG. 3a shows the layout of a portal frame, which consists of two parallel beams 301a, 301b of length Ls, depth ds in the plane of the figure and breadth bs perpendicular to the figure. The depth ds is assumed to be much less than the breadth bs, so that the stiffness is much lower against in-plane displacements than against out-of plane displacements. The beams are rigidly attached to a support 302 at one end (the built-in end) and linked by a rigid element 303 at the other (the free end). The support 302 corresponds to the lands 201a, 201b in FIGS. 1 and 2. Similarly, the feature 303 corresponds to the electrode attachment points 107a, 107b and the beams 301a, 301b to the flexible elements linking the lands to the attachment points. The support 302 is attached to a substrate below. The beams 301a, 301b and the feature 303 are suspended above the substrate and are free to move. If an in-plane transverse end load is applied to the structure shown in FIG. 3a, the free end will deflect transversely. However, the rigid element 303 linking the two beams 301a, 301b ensures that these elements cannot rotate at their free ends. The deflection may be analysed by considering the deflection of a single beam 304 attached to a land 305 under an end load P as shown in FIG. 4b. Here the constraints of the portal arrangement are modeled by applying an end moment Me, to the beam, whose value is chosen to prevent end rotation. The radius of curvature R and the deflection y(x) of a loaded beam can be determined as a function of the position x along the beam from the Euler equation (see e.g. [Young 1989]):1/R≈d2y/dx2=M/EsIs (1) Here M is the local bending moment, Es is the Young's modulus of the beam material and Is is its second moment of area. For a beam of breadth bs and depth ds, the second moment of area is [Young 1989]:Is=bsds3/12 (2) Including the effects of an end load P and an end moment Me, the local bending moment is:M=−P(L−x)+Me (3) Integrating Equation 1 twice, subject to the boundary conditions y=dy/dx=0 at x=0 and dy/dx=0 at x Ls, the end-moment Me and the deflection y(x) may be found asMe=PLs/2y(x)=−P(Lsx2/4−x3/6)/EsIs (4) Consequently the end deflection is:y(Ls)=−PLs3/12EsIs (5) Here the negative sign arises from the choice of co-ordinate system used. The stiffness ks of the beam is the deflection per unit load, or k=−y(Ls)=12EsIs/Ls3. In the portal frame suspension, there are two such elements in parallel, so the stiffness kP of the portal frame is kP=24EsIs/Ls3. Using Equation 2, the overall stiffness may be written as:kP=2Esbsds3/Ls3 (6) Thus, it will be apparent that the stiffness of the portal frame is determined from the elastic property Es of the suspension material and the design dimensions bs, ds and Ls of the beams. Appropriate choice of these parameters may therefore provide a suitable stiffness. Generally, the stiffness will be chosen to allow thermal expansion to take place without over-straining the elastic suspension or buckling the cylindrical electrodes. For example, assuming that the length and thermal expansion coefficient of the cylindrical electrodes are Le and αe respectively, and that the thermal expansion coefficient of the substrate assembly is αs, the differential thermal expansion between the electrodes and the substrate arising from a temperature rise ΔT is:Δ=(αe−αs)LeΔT (7) For example, assuming that αe≈15×10−6 K−1, αs=2.5×10−6 K−1, Le=25 mm and ΔT=100 K, we obtain Δ=31.25 μm. Assuming that this expansion is entirely accommodated by a deflection of the elastic suspension, the load P on each beam element may be found from Equations 5 and 2 as:P=Esbsds3Δ/Ls3 (8) Now the maximum strain in a beam of depth d, bent through a radius R is ε=ds/2R [Young 1989]. The maximum value of 1/R can be found from Equation 1 and 4 as PLs/2EsIs. Combining this result with Equations 2 and 8, the maximum strain εmax is:εmax=3dsΔ/Ls2 (9) Equation 9 implies that the maximum strain may be reduced to a given safe value (for example, 0.1%) for a given displacement A by appropriate choice of ds and Ls. Generally, there are restrictions on the minimum value of ds that may be reliably formed by a microfabrication process. Given this value, the suspension length may be estimated asLs=(3dsΔ/εmax)1/2 (10) Assuming that d≈50 μm is appropriate for a silicon substrate of thickness 500 μm, Equation 10 implies that Ls≈2 mm is a suitable suspension length if εmax=0.001. With these parameters, and assuming that Es=150×109 N/m2 for silicon, the stiffness of the portal frame suspension may be found from Equation 6 as kp≈2350 N/m. For a displacement Δ=31.25 μm, the resulting force on each suspension beam is P≈0.035 N. The portal frame arrangement will support a load of twice this value, namely PP≈0.07 N in response to a deflection Δ caused by differential thermal expansion, and hence will apply a load PP to each cylindrical electrode. The effect of this load may be considered as follows. Using the Euler equation in conjunction with an axial load, it can be shown that the critical load PC at which a beam that is clamped at both ends to prevent rotation will buckle is (see e.g. [Young 1989]):PC=4π2EeLe/Le2 (11) Here Ee, Ie and Le are the Young's modulus, second moment of area and length of the beam, respectively. For a cylindrical beam corresponding to a cylindrical electrode the second moment of area is Ie=πre4/4. Assuming the typical values of re=250 μm, Le=25 mm and that Ee≈200×109 N/m2 for stainless steel, we obtain PC≈40 N. Since this value of PC is much greater than the value of PP found above, it is clear that the cylindrical electrode will not buckle under to the force of the suspension. It will therefore be evident that a satisfactory strain relieving suspension based on a portal frame may easily be designed. It will be evident that other elastic arrangements will provide a similar result. For example, the portal frame may be constructed with more than two parallel beams. Similarly, the elastic suspension may be formed from components in the substrate layer, if this is a suitably elastic material. More complex arrangements may also be used to obtain a more exact approximation to linear motion. For example, as the portal frame deflects, the initial linear shape of the two beams should desirably transform into the curved shape defined by Equation 4. To accommodate this shape, the free ends of the beams should correspondingly deflect axially. This deflection is second-order, and may be unimportant. However, its effects may be compensated by a folded flexure design such as that described in the aforementioned Tang paper [Tang 1989]. Following the teaching of GB0701809.6, the content of which is incorporated herein by way of reference, a complete quadrupole may be constructed from combining two of the assemblies in FIG. 1 as shown in FIGS. 4a and 4b. It will be understood that this example of an application of the mounting arrangement provided by the teaching of the present invention is provided as an illustration of the benefit that may be accrued from using a electrode mounting arrangement as herein described. It is not intended to limit the application of the teaching of the present invention to such an exemplary embodiment. As shown in FIGS. 4a and 4b, when fabricating such a quadrupole, two assemblies 401a and 401b carrying mounted cylindrical electrodes may be placed together so that the partial shields 402a and 402b align and abut. The two assemblies are then fixed in position. The two partial shields 402a, 402b now combine to form a complete shield surrounding but not contacting the cylindrical electrodes 403a, 403b, 403c, 403d, which are mounted on fixtures such as 404a, 404b, 404c, 404d. The two partial shields 402a, 402b also provide appropriate spacing between the two substrates 405a, 405b so that the four cylindrical electrodes are arranged as a quadrupole. It will be understood that each of the partial shields may be considered mating members having opposing mating surfaces which abut and when the two substrates are brought together to form the sandwich structure of the quadrupole. Following the teaching of GB0701809.6, FIG. 5 shows in section how the main geometric parameters of the microfabricated quadrupole mount are established. Here, a fixed feature 501 supporting a single cylindrical electrode 502 of radius re is shown, together with a spacer layer 503. Conventionally it is desired to hold a cylindrical electrode of radius re at an equal distance s from the two axes of symmetry 504, 505 of the electrostatic field created by the quadrupole assembly. The geometry is determined by the radius r0 of a circle 506 that can be drawn between the four electrodes. Research has shown that a good approximation to a hyperbolic potential is obtained from cylindrical electrodes when re=1.148 r0 [Denison 1971]. The distance s from the axes of symmetry to the electrode centreline is then s={re+r0}/21/2. If the distance between the contact points 507a, 507b of the cylindrical electrode 502 and the groove in the support 501 is 2 w, the height h and hence the thickness of the spacer 503 between the contact points and the axis of symmetry 504 is h=s+(re2−w2)1/2. Suitable choices of re, r0, s, w and h therefore allow the correct geometry to be established. Substrates of the type described may be constructed with micron-scale precision by microfabrication, using methods such as photolithography, plasma etching, metal coating and dicing. However, as will be apparent to those skilled in the art, there are many combinations of processes and materials yielding similar results. We therefore give one example, which is intended to be representative rather than exclusive. In this example, etched features are formed on silicon wafers, which are then stacked together to form batches of complete substrates. The substrates are then separated by dicing. FIG. 6 shows how two sets of parts are formed on two separate silicon wafers. The first wafer 601 carries parts defining all features of a spacer layer lying above contact points of the type shown, as 507a, 507b in FIG. 5. Because these features desirably have the height h shown in FIG. 5, the starting material is a silicon wafer, which is polished on both sides to this thickness. The wafer is patterned using photolithography to define the desired features (for example, the shield spacer 602) together with small sections (for example 603) attaching them to the surrounding wafer 604. The pattern is transferred right through the wafer using deep reactive ion etching, a plasma-based process that may etch arbitrary features in silicon at a high rate and with high verticality [Hynes 1999]. The wafer is then cleaned and metallised, for example by RF sputtering of gold. The second wafer carries parts defining all features of the microfabricated substrate lying below the two contact points 507a, 507b in FIG. 5. Because the depth of these features is not critical in determining the accuracy of the quadrupole assembly, the thickness of this wafer is chosen mainly to allow sufficient mechanical strength. The wafer is patterned three times. In the first step, the wafer is patterned to define partially etched features on the rear side of the wafer such as the land 605 that supports the flexible electrode mount 606. In the second step, the wafer is patterned to define partially etched features of the front side of the wafer such as the seating features for the cylindrical electrodes (for example, 607) and the trench 608 in the conducting shield 609. In the third step the wafer is patterned to define fully etched features outlining all the main parts. Once again, features are attached to the surrounding substrate 611 by short sections (for example, 610). The patterns are again transferred into the wafer using deep reactive ion etching, so that the partially etched features on the front side of the wafer are etched to the sufficient depth de in FIG. 5 and the fully etched features are transferred right through. Multilevel etching of this type may easily be performed using a multilevel surface mask, well known to those skilled in the art [Mita 2000]. The lithographic masks are removed, and the wafer is cleaned and metallized. Suitable coating metals again include gold. FIG. 7 shows how the wafers are assembled into a stack forming a set of complete microfabricated assemblies. The upper wafer 701 is attached to the lower wafer 702, which is in turn attached to an insulating substrate 703, for example a glass wafer. An alternative substrate material is a ceramic. Suitable attachment methods include silicon-silicon direct bonding, silicon-glass anodic bonding and gold-to-gold compression bonding. Depending on which process is used, metallisation may take place before or after assembly. Rectangular dies comprising individual microfabricated substrates are then separated using a dicing saw, for example by sawing along a first set of parallel lines 704a, 704b, which separate all sections of sprue, and a second set of orthogonal parallel lines 705a, 705b. Quadrupoles are then completed, by inserting cylindrical electrodes into microfabricated substrates as previously shown in FIGS. 1 and 2 and then assembling two such substrates as previously shown in FIG. 4. Wirebond connections to external circuitry are then attached to the cylindrical electrode supports and to the shield. It will be appreciated that the processes described above can be used to construct a microfabricated quadrupole containing the main features described, namely electrically-isolated supports for cylindrical electrodes in both fixed and suspended arrangements, and a conducting shield, the overall assembly having the correct geometrical relationship. However, it will also be appreciated that many alternative fabrication processes can achieve a similar result. For example, the lower silicon wafer may be replaced with a silicon-on-glass wafer, thus eliminating the need for the lower wafer-bonding step shown in FIG. 7. Alternatively, the two silicon wafers may be combined together into a single layer, which is multiple structured by etching to combine all the necessary features, thus eliminating the need for the upper wafer-bonding step shown in FIG. 7. In this case, the precision needed to define the height h may be achieved using a buried etch stop, which may be provided using a bonded-silicon-on-insulator wafer. It will be understood that exemplary applications of a flexible mounting arrangement have been described with reference to specific embodiments in the field of quadrupole mass spectrometers. While such a mounting arrangement is particularly useful in provision of a mounting for a miniature quadrupole mass filter, linear quadrupole ion trap or quadrupole ion guide, in which good electrical performance is combined with mechanical insensitivity to temperature variations, it is not intended that the present invention be so limited in that any mounting arrangement for an electrode onto a support member that benefits from provision of a compensation for thermal coefficient differences between both the electrode and the support member could benefit from a system or arrangement provided in accordance with the teaching of the invention. Furthermore, whereas the quadrupole example has been described with reference to a single set of four electrodes mounted relative to one another in a quadrupole arrangement, it will be understood that the mounting arrangement provided in accordance with the teaching of the invention could be equally used in the provision of a tandem mass spectrometer, i.e. that type of mass spectrometer where two quadrupoles are arranged co-axially. Within the context of the present invention the term microengineered or microengineering or microfabricated or microfabrication is intended to define the fabrication of three dimensional structures and devices with dimensions in the order of microns. It combines the technologies of microelectronics and micromachining. Microelectronics allows the fabrication of integrated circuits from silicon wafers whereas micromachining is the production of three-dimensional structures, primarily from silicon wafers. This may be achieved by removal of material from the wafer or addition of material on or in the wafer. The attractions of microengineering may be summarised as batch fabrication of devices leading to reduced production costs, miniaturisation resulting in materials savings, miniaturisation resulting in faster response times and reduced device invasiveness. Wide varieties of techniques exist for the microengineering of wafers, and will be well known to the person skilled in the art. The techniques may be divided into those related to the removal of material and those pertaining to the deposition or addition of material to the wafer. Examples of the former include: Wet chemical etching (anisotropic and isotropic) Electrochemical or photo assisted electrochemical etching Dry plasma or reactive ion etching Ion beam milling Laser machining Excimer laser machining Whereas examples of the latter include: Evaporation Thick film deposition Sputtering Electroplating Electroforming Moulding Chemical vapour deposition (CVD) Epitaxy These techniques can be combined with wafer bonding to produce complex three-dimensional, examples of which are the interface devices provided by the present invention. Where the words “upper”, “lower”, “top”, bottom, “interior”, “exterior” and the like have been used, it will be understood that these are used to convey the mutual arrangement of the layers relative to one another and are not to be interpreted as limiting the invention to such a configuration where for example a surface designated a top surface is not above a surface designated a lower surface. Furthermore, the words comprises/comprising when used in this specification are to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof. References Paul W., Raether M. “Das electrische massenfilter” Z. Physik 140, 262-273 (1955). Dawson P. H. “Quadrupole mass spectrometry and its applications” Elsevier Scientific Pub. Co., Amsterdam (1976). Denison D. R. “Operating parameters of a quadrupole in a grounded cylindrical housing” J. Vac. Sci. & Tech. 8 266-269 (1971). Dawson P. H. “Performance characteristics of an RF-only quadrupole” Int. J. Mass Spect. Ion Proc. 67, 267-276 (1985). Miller P. E., Bonner Denton M. “The transmission properties of an RF-only quadrupole mass filter” Int. J. Mass Spect. 72, 223-238 (1986). Douglas D. J. “Applications of collision dynamics in quadrupole mass spectrometry” J. Am. Soc. Mass Spect. 9, 101-113 (1998). 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M., Taylor S. “Fabrication of a microengineered quadrupole electrostatic lens” Elect. Lett. 32, 2094-2095 (1996). Syms R. R. A., Tate T. J., Ahmad M. M., Taylor S. “Design of a microengineered quadrupole electrostatic lens” IEEE Trans. on Electron Devices TED-45, 2304-2311 (1998). Taylor S., Tunstall J. J., Leck J. H., Tindall R., Julian P., Batey J., Syms R. R. A., Tate T. J., Ahmad M. M. “Performance improvements for a miniature quadrupole with a micromachined mass filter” Vacuum 53, 203-206 (1999). Syms R. R. A. “Monolithic microengineered mass spectrometer” GB 2391694 Mar. 1 (2006). Geear M., Syms R. R. A., Wright S., Holmes A. S. “Monolithic MEMS quadrupole mass spectrometers by deep silicon etching” IEEE/ASME J. Microelectromech. Syst. 14, 1156-1166 (2005). Syms R. R. A. “High performance microfabricated electrostatic quadrupole lens” GB0701809.6 Jan. 31 (2007). Young W. C. “Roark's formulas for stress and strain”, 6th Edn., McGraw Hill International, New York (1989). Tang W. C., Nguyen T.-C. H., Howe R. T. “Laterally driven polysilicon resonant microstructures” Sensors and Actuators 20, 25-32 (1989). Hynes A. M., Ashraf H., Bhardwaj J. K., Hopkins J., Johnston I., Shepherd J. N. “Recent advances in silicon etching for MEMS using the ASEM process” Sensors and Actuators 74, 13-17 (1999). Mita Y., Tixier A., Oshima S., Mita M., Gouy J.-P., Fujita H. “A silicon shadow mask with unlimited patterns and a mechanical alignment structure by Al-delay masking process” Trans. JIEE 120-E, 357-362 (2000).
	claims	1. An alternate feedwater injection system to at least partially mitigate the effects of an aircraft impact on a light water nuclear reactor positioned in a reactor building, the light water nuclear reactor having a reactor core and a primary system, the alternate feedwater injection system, comprising:a water storage tank located external to and separate from the reactor building, and outside an identified aircraft impact area for protection from the aircraft impact;an injection point located in feedwater piping;a pump to transfer water from the water storage tank to the injection point and ultimately to the reactor core, the pump located external to the reactor building and housed in an independent structure separate from the reactor building for protection from the aircraft impact;inlet piping to connect the water storage tank to the pump, the inlet piping positioned in an above ground structure or in an underground structure for protection from the aircraft impact; anddischarge piping to connect the pump to the reactor core, the discharge piping positioned in an above ground structure or in an underground structure for protection from the aircraft impact. 2. The system of claim 1, wherein the pump transfers water to the injection point at an operating pressure of the reactor core. 3. The system of claim 1, wherein, the pump transfers water at a sufficient flow rate such that nuclear fuel in the reactor core remains substantially covered by water. 4. The system of claim 1 wherein, the pump is located in a structure positioned above ground. 5. The system of claim 1 wherein, the pump is located in a structure positioned underground. 6. The system of claim 1 wherein, the discharge piping conduit is located in an underground bunker. 7. The system of claim 1, wherein, the nuclear reactor is selected from a boiling water reactor and a pressurized water reactor.
	abstract	An illumination optical unit for a mask inspection system is used with EUV illumination light. A hollow waveguide of the illumination optical unit serves for guiding the illumination light. The hollow waveguide has an entry opening for the illumination light and an exit opening for the illumination light. An imaging mirror optical unit, arranged downstream of the hollow waveguide serves to image the exit opening into an illumination field. This results in an illumination optical unit, the throughput of which is optimized for the EUV illumination light.
051204916	claims	1. A thimble tube for use in a guide tube in a nuclear reactor, comprising: a. an elongated hollow tube having one end closed; b. the portion of said tube that extends into the reactor being formed from two or more sections attached to each other edge-to-edge in a spiral fashion to form said tube; and c. said sections being formed from materials having different thermal coefficients of expansion such that at normal reactor operating temperature said tube is caused to warp into supporting contact with the interior of the guide tube. 2. The thimble tube of claim 1, wherein said sections are respectively formed from inconel and stainless steel.
	claims	1. A system, comprising:a nuclear reactor vessel configured to include a nuclear reactor coolant system and to circulate nuclear reactor coolant of the nuclear reactor coolant system;a feedwater system for producing electric power connected to the nuclear reactor vessel;a steam generator inside of the nuclear reactor vessel;a turbine configured to produce electric power from the feedwater system; anda nuclear reactor cooling and power generation system configured to produce electric power during an accident of a nuclear power plant to produce electric power,the nuclear reactor cooling and power generation system for producing electric power comprising:a heat exchange section formed to include a fluid inside the heat exchange section and formed to receive heat generated from a core inside the nuclear reactor vessel to the fluid during a normal operation of the nuclear power plant; andan electric power production section comprising a Stirling engine formed to produce electric energy using the energy of the fluid whose temperature has increased while receiving the heat of the nuclear reactor, andwherein the heat exchange section is fluidly separated from the feedwater system, the steam generator, and the turbine,wherein during the normal operation of the nuclear power plant, steam produced by the steam generator is passed through a main steam line and supplied to the turbine to produce electric power, andwherein the nuclear reactor cooling and power generation system is formed to circulate the fluid that has received heat from the core in the heat exchange section through the electric power production section, and operates even during the normal operation and during the accident of the nuclear power plant, to produce electric power. 2. The system of claim 1, wherein the electric power produced during the normal operation of the nuclear power plant is supplied to an internal and external electric power system and an emergency battery. 3. The system of claim 2, wherein the electric energy charged in the emergency battery is formed to supply an emergency electric power as an emergency power source during an accident. 4. The system of claim 1, wherein the electric power produced during an accident of the nuclear power plant is formed to be supplied to an emergency power source of the nuclear power plant. 5. The system of claim 3, wherein the emergency power source is formed to supply an electric power for the operation of a nuclear safety system or valve manipulating for the operation of the nuclear safety system or monitoring the nuclear safety system or operation of the nuclear reactor cooling and power generation system during an accident of the nuclear power plant. 6. The system of claim 1, wherein a seismic design of seismic category I, II or III is applied thereto. 7. The system of claim 1, wherein a safety grade of safety class 1, 2 or 3 is applied thereto. 8. The system of claim 1, further comprising:a first discharge section connected to the heat exchange section,wherein the first discharge section is formed to discharge at least a part of the fluid excessively supplied to the electric power production section. 9. The system of claim 8, wherein the heat exchange section is formed to surround at least a part of the nuclear reactor vessel, and has a shape capable of cooling an outer wall of the nuclear reactor vessel formed to receive heat discharged from the nuclear reactor vessel that has received heat generated from the core. 10. The system of claim 9, wherein at least a part of the shape of the heat exchange section having a shape of cooling the outer wall of the nuclear reactor vessel comprises a cylindrical shape, a hemispherical shape, a double vessel shape, or a mixed shape thereof. 11. The system of claim 9, further comprising:an in-containment refueling water storage tank (IRWST) configured to supply refueling water to the heat exchange section having a shape capable of cooling the outer wall of the nuclear reactor vessel. 12. The system of claim 11, further comprising:a second discharge section provided in a heat exchange section having a shape capable of cooling the outer wall of the nuclear reactor vessel,wherein the second discharge section is formed to discharge the refueling water supplied from the in-containment refueling water storage tank (IRWST). 13. The system of claim 9, wherein a coating member is further formed on the heat exchange section having a shape capable of cooling the outer wall of the nuclear reactor vessel to prevent the corrosion of the nuclear reactor vessel. 14. The system of claim 13, wherein a surface of the coating member is chemically treated to increase a surface area thereof. 15. The system of claim 9, wherein a heat transfer member is further formed to transfer heat discharged from the nuclear reactor vessel. 16. The system of claim 15, wherein a surface of the heat transfer member is chemically treated to increase a surface area thereof. 17. The system of claim 8, wherein the heat exchange section is provided inside the nuclear reactor vessel, and has a shape capable of cooling an inside of the nuclear reactor vessel formed to receive heat discharged from a nuclear reactor coolant system inside the nuclear reactor vessel that has received heat generated from the core. 18. The system of claim 17, further comprising:an in-containment refueling water storage tank (IRWST) configured to supply refueling water to the heat exchange section having a shape capable of cooling an inside of the nuclear reactor vessel. 19. The system of claim 18, further comprising:a second discharge section is provided in a heat exchange section having a shape capable of cooling the inside of the nuclear reactor vessel, andwherein the second discharge section is formed to discharge the refueling water supplied from the in-containment refueling water storage tank (IRWST). 20. The system of claim 1, further comprising:an evaporator section connected to the heat exchange section,wherein the evaporator section is formed to exchange heat with an inner fluid of the heat exchange section and an inner fluid of the electric power production section, and comprises a first circulation section formed to circulate through the heat exchange section and the evaporator section; and a second circulation section formed to circulate through the evaporator section and the electric power production section. 21. The system of claim 20, wherein at least one of the first circulation section and the second circulation section is formed to circulate by a single-phase fluid. 22. The system of claim 1, wherein the heat exchange section further comprises a core catcher, and the core catcher is formed to receive and cool a melted core when the core is melted in the nuclear reactor vessel. 23. The system of claim 1, wherein the Stirling engine comprises:a power generation section comprising a cylinder having a reciprocator and a piston configured to generate motive power by heat received through the fluid that has received heat, and a power transmission section; andan electricity generation section configured to convert mechanical energy generated by the power generation section into electrical energy. 24. The system of claim 1, wherein the Stirling engine comprises a first temperature section and a second temperature section respectively filled with working gas, and formed with spaces partitioned from each other inside a cylinder, andworking gases filled in the first temperature section and the second temperature section are formed to communicate with each other, and formed to move a reciprocator and a piston according to the communication of the working gas. 25. The system of claim 24, wherein the Stirling engine further comprises a regenerative heat exchange section, andthe regenerative heat exchange section transfers and stores heat stored in the working gas in the regenerative heat exchange section when the working gas moves from the first temperature section to the second temperature section, and transfers the heat stored in the regenerative heat exchange section to the working gas when the working gas returns from the low second temperature section to the first temperature section. 26. The system of claim 24, wherein a fan or a pump is provided in the second temperature section, andthe fan or the pump is formed to supply a cooling fluid to the second temperature section to exchange heat with the working gas of the second temperature section. 27. The system of claim 26, wherein the cooling fluid comprises air, pure water, seawater, or a mixture thereof. 28. The system of claim 1, further comprising:a condensate storage section at a lower portion of the electric power production section to collect condensate generated by condensing the fluid heat-exchanged in the electric power production section. 29. The system of claim 28, wherein condensate in the condensate storage section is supplied to the heat exchange section by gravity or the power of the pump.
	summary
	claims	1. A floating nuclear power reactor, comprising:a floating vessel having a bottom positioned beneath the water level of a body of water, sides extending upwardly from said bottom, and an upper end which is positioned above the water level of the body of water;said floating vessel including an upstanding cylindrical support structure having a lower end, an upstanding cylindrical side wall, having inner and outer surfaces, and a closed upper end;a nuclear power reactor positioned within said cylindrical support structure;said nuclear power reactor including an upstanding containment structure having a lower end positioned on said bottom of said floating vessel, an upstanding side wall, having upper and lower ends, which is in engagement with said inner surface of said side wall of said cylindrical support structure and a domed upper end;said containment structure defining a sealed interior compartment, having upper and lower ends;said domed upper end of said containment structure and said upper end of said side wall of said cylindrical support structure and said closed upper end of said cylindrical support structure defining a vent chamber;said vent chamber being filled with a filter material;at least one first steam exhaust pipe extending from said vent chamber to the atmosphere;at least one second steam exhaust pipe extending from said upper end of said interior compartment of said containment structure into said vent chamber;an upstanding reactor vessel, having upper and lower ends, is positioned in said interior compartment of said containment structure;said reactor vessel having an interior compartment with upper and lower ends;a third steam exhaust pipe extending from said upper end of said interior compartment of said reactor vessel outwardly through said containment structure to a turbine;a normally open valve imposed in said third steam exhaust pipe;a by-pass steam exhaust pipe extending from said third steam exhaust pipe, outwardly of said containment structure, to said vent chamber;a normally closed valve in said by-pass steam exhaust pipe;at least one first return pipe, filled with a liquid, extending outwardly from said upper end of said interior compartment of said reactor vessel into said interior compartment of said containment structure, thence downwardly, and thence inwardly into said interior compartment of said reactor vessel at said lower end thereof, and thence upwardly within said interior compartment of said reactor vessel to form a closed loop return pipe;a first water passageway, having inner and outer ends, extending through said bottom of said containment structure;said outer end of said first water passageway being in fluid communication with the body of water;said inner end of said first water passageway being in fluid communication with said interior compartment of said containment structure;a normally closed first hatch associated with said first water passageway;said first hatch being movable between a closed position and an open position;said first hatch, when in said closed position, closing said first water passageway;said first hatch, when in said open position, permitting water from the body of water to flow inwardly through said first water passageway into said interior compartment of said containment structure;a second water passageway, having inner and outer ends, extending through said bottom of said containment structure;said outer end of said second water passageway being in fluid communication with the body of water;said inner end of said second water passageway being in fluid communication with said interior compartment of said reactor vessel;a normally closed second hatch movably associated with said second water passageway;said second hatch being movable between a closed position and an open position;said second hatch, when in said closed position, closing said second water passageway;said second hatch, when in said open position, permitting water from the body of water to flow inwardly through said second water passageway into said interior compartment of said reactor vessel;said first hatch being movable from its said closed position to its said open position when a condition within said interior compartment of said containment structure reaches a predetermined level thereby permitting water from the body of water to flow into said interior compartment of said containment structure; andsaid second hatch being movable from its said closed position to its said open position when a condition within said interior compartment of said reactor vessel reaches a predetermined level thereby permitting water from the body of water to flow into said interior compartment of said reactor vessel. 2. The floating nuclear power reactor of claim 1 wherein the predetermined condition level within said interior compartment of containment structure is lower than the predetermined condition level of within said interior compartment of said reactor vessel whereby said first hatch will move from its said closed position to its said open position prior to said second hatch moving from its said closed position to its said open position so that said interior compartment of said containment structure will be flooded prior to said interior compartment of said reactor vessel being flooded. 3. The floating nuclear power reactor of claim 1 wherein a plurality of first steam exhaust pipes extend from said vent chamber to the atmosphere. 4. The floating nuclear power reactor of claim 1 wherein a plurality of second steam exhaust pipes extend from said upper end of said interior compartment of said containment structure into said vent chamber. 5. The floating nuclear power reactor of claim 1 wherein said filter material is comprised of rocks, chemicals and water. 6. The floating nuclear power reactor of claim 1 wherein at least one second return steam pipe extends outwardly from said upper end of said interior compartment of said reactor vessel, thence downwardly, and thence inwardly into said interior compartment of said reactor vessel at said lower end thereof. 7. The floating nuclear power reactor of claim 1 wherein a valve is imposed in said third steam exhaust pipe. 8. The floating nuclear power reactor of claim 7 wherein said valve is imposed in said third steam exhaust pipe outwardly of said containment structure. 9. A floating nuclear power reactor, comprising;a floating vessel having a bottom positioned beneath the water level of a body of water, sides extending upwardly from said bottom, and an upper end which is positioned above the water level of the body of water;said floating vessel including an upstanding cylindrical support structure having a lower end, an upstanding cylindrical side wall, having inner and outer surfaces, and a closed upper end;a nuclear power reactor positioned within said cylindrical support structure;said nuclear power reactor including an upstanding containment structure having a lower end positioned on said bottom of said floating vessel, an upstanding side wall, having upper and lower ends, which is in engagement with said inner surface of said side wall of said cylindrical support structure and a domed upper end;said containment structure defining a sealed interior compartment, having upper and lower ends;said domed upper end of said containment structure and said upper end of said side wall of said cylindrical support structure and said closed upper end of said cylindrical support structure defining a vent chamber;said vent chamber being filled with a filter material;at least one first steam exhaust pipe extending from said vent chamber to the atmosphere;at least one second steam exhaust pipe extending from said upper end of said interior compartment of said containment structure into said vent chamber;an upstanding reactor vessel, having upper and lower ends, in said interior compartment of said containment structure;said reactor vessel having an interior compartment with upper and lower ends;a third steam exhaust pipe extending from said upper end of said interior compartment of said reactor vessel outwardly through said containment structure to a turbine;a by-pass steam exhaust pipe extending from said third steam exhaust pipe, outwardly of said containment structure, to said vent chamber;a normally closed valve in said by-pass steam exhaust pipe;at least one first return pipe, filled with a liquid, extending outwardly from said upper end of said interior compartment of said reactor vessel into said interior compartment of said containment structure, thence downwardly, and thence inwardly into said interior compartment of said reactor vessel at said lower end thereof, and thence upwardly within said interior compartment of said reactor vessel to form a closed loop return pipe;a first water passageway, having inner and outer ends, extending through said bottom of said containment structure;said outer end of said first water passageway being in fluid communication with the body of water;said inner end of said first water passageway being, in fluid communication with said interior compartment of said containment structure;a normally closed first hatch associated with said first water passageway;said first hatch being movable between a closed position and an open position;said first hatch, when in said closed position, closing said first water passageway;said first hatch, when in said open position, permitting water from the body of water to flow inwardly through said first water passageway into said interior compartment of said containment structure;said first hatch being movable from its said closed position to its said open position upon the temperature or pressure in said interior compartment of said containment structure reaching a predetermined level;a second water passageway, having inner and outer ends, extending through said bottom of said containment structure;said outer end of said second water passageway being in fluid communication with the body of water;said inner end of said second water passageway being in fluid communication with said interior compartment of said reactor vessel;a normally closed second hatch movably associated with said second water passageway;said second hatch being movable between a closed position and an open position;said second hatch, when in said closed position, closing said second water passageway;said second hatch, when in said open position, permitting water from the body of water to flow inwardly through said second water passageway into said interior compartment of said reactor vessel; andsaid second hatch being movable from its said closed position to its said open position upon the temperature or pressure in said interior compartment of said reactor vessel reaching a predetermined level.
052326551	abstract	A nuclear fuel assembly comprises a skeleton that constitutes the structure of the assembly and that holds a bundle of fuel elements at nodes in a regular array. The skeleton comprises two end pieces interconnected by guide tubes. The connection between each guide tube and the lower end piece comprises a peg formed with a coolant flow hole having a top portion fixed in the guide tube and a projecting bottom portion, which has a downwardly facing shoulder for bearing on the lower end piece, which passes through a passage formed in the lower end piece, and which is divided into a plurality of resilient fingers each having an upwardly facing shoulder for catching on the lower end piece.
	summary
048805955	claims	1. A process for cleaning nuclear reactor cooling water, which comprises contacting nuclear reactor cooling water with an ion exchange resin mixture of (a) 50 to 90% by weight of a cation exchange carboxylic acid-based resin having an average particle size of 30 to 60 .mu.m, and (b) 10 to 50% by weight of anion exchange resin, said mixture being reinforced with 10 to 40% by weight of reinforcing fibers on a dry basis of total weight of said resins and said fibers, thereby trapping cruds or cations in the cooling water; wherein the cation exchange carboxylic acid-based resin is a straight chain type ion exchange resin whose ion-exchange groups are bonded to other elements than carbon atoms constituting a benzene ring. 2. A process according to claim 1, wherein the cation exchange carboxylic acid-based resin is at least one of acrylic carboxylic acid resin and methacrylic carboxylic acid resin. 3. A process according to claim 1, wherein a bonding energy of ion-exchanging groups of said cation exchange carboxylic acid-based resin is not more than 300 KJ/mole. 4. A process according to claim 1, wherein said ion exchange resin mixture is made up of 60 to 85% by weight of said cation exchange carboxylic acid-based resin and 15 to 40% by weight of said anion exchange resin.
047770112	claims	1. Method for checking the dimensions of a nuclear reactor fuel assembly in a water tank, with two mutually parallel probes each having a first probe side carrying an ultrasonic test head at a free end thereof with acoustic directions directed towards each other and each having a second probe side facing away from the ultrasonic test head, which comprises transmitting acoustic waves with one of the ultrasonic test heads, receiving the transmitted acoustic waves with the other ultrasonic test head, bringing one of the second probe sides into contact with a given region of the fuel assembly to be checked, moving the probes towards each other in the direction of the acoustic waves due to contact pressure with the fuel assembly, indicating and assessing the probe movement by a reduction of transit time of the acoustic waves between the test heads, and deriving the actual dimension of the fuel assembly region to be checked while accounting for the dimension of probe movement. 2. Device for checking the dimensions of a nuclear reactor fuel assembly in a water tank, comprising two mutually parallel probes having free ends, first probe sides facing toward each other and second probe sides facing away from each other, ultrasonic test heads each being disposed on a respective one of said first probe sides at said free end of one of said probes, said ultrasonic test heads having acoustic directions directed towards each other, one of said ultrasonic test heads transmitting acoustic waves and the other of said ultrasonic test heads receiving the transmitted acoustic waves, a feeler disposed on one of said second probe sides, a roller connected to said feeler, means for bringing said roller into contact with a given region of the fuel assembly to be checked causing said probes to be moved closer together in the direction of the acoustic waves due to contact pressure with the fuel assembly, means for indicating and assessing movement of said probes by a reduction of transit time of the acoustic waves between said test heads, and means for deriving the actual dimension of the given fuel assembly region to be checked while accounting for dimensions of movement of said probes.
	claims	1. A modular shielding structure for radiation protection in a radiotherapy room comprising:at least one wall structure comprising at least two rows;the first wall row comprising a row of base modules including first and second base modules aligned along a common longitudinal axis in a sliding relationship such that a front face of a first base module and a rear face of a second base module abut, where further base modules are arranged to maintain the pattern of face abutment established by the first and second base modules until a row of predetermined length and where a bottom row of complementary modules are positioned to fill any gap on a lower side of a base module row;second and subsequent wall rows comprising the arrangement of the first wall row placed on top of or adjacent to the first wall row successively and up to a desired wall height such that bottom surfaces of second or subsequent wall rows abut top surfaces of a preceding wall row;a second wall base module aligned such that a longitudinal axis of the second wall base module is perpendicular to that of a wall base module located in a lower corner of the wall;a front face of a second wall base module is contacting a first top row of complementary modules filling a gap on an upper side of a wall top; andwherein, said base modules comprise two identical cuboids fused together, each of these cuboids having equally sized front and rear faces connected with four rectangular sides comprising left, right, top, and bottom sides and being positioned in parallel, side-by-side, along mutually facing rectangular side and where the cuboids are also mutually offset vertically and horizontally; andwherein, said complementary modules comprise a single cuboid having equally sized rectangular front and rear faces connected with four rectangular sides comprising left, right, top, and bottom sides, the complementary modules having top and bottom edges equal in length to the length of the edges of base module faces and side edges one half the length of the edges base module faces, and the complementary modules comprise top and bottom sides equal in dimension to the dimensions of the sides of base module cuboids, left and right sides with length equal to the lengths of complementary module top and bottom sides, and widths equal to the dimension of side edges of complementary module faces. 2. The modular shielding structure of claim 1, further comprising second wall structure, the second wall structure comprising plural base modules and plural complementary modules, the second wall structure arranged perpendicular a first wall structure and comprising second wall structure base modules perpendicular the first wall structure base modules and in contact with first wall base modules such that the second wall structure base module faces abut the sides of the first wall base modules; andwherein the second wall structure comprises the same components and basic arrangement of the wall structure of claim 1 such that the second wall structure is composed of sufficient base modules and complementary modules to have a desired height. 3. The modular shielding structure of claim 1 further comprising each of said base modules and complementary modules are made of metal casing and filled internally with metal powder.
059616792	claims	1. A method for the conversion of radioactive waste and other waste material into glass comprising the steps of: a) providing a bath of molten B.sub.2 O.sub.3 and PbO; b) forming a molten dissolution glass comprising xPbO:B.sub.2 O.sub.3 ; c) adding said waste to said dissolution glass to form a molten glass/waste mixture, wherein metals and metal compounds in said waste are oxidized to yield metal oxides, molten lead is formed, noble metals are dissolved in said lead, and halogens are converted to lead halides which are gases at the temperature of the molten mixture; d) separating said gases from said molten mixture; e) contacting said gases with an aqueous scrubber solution of an alkali metal hydroxide to yield a soluble alkali metal halide and a lead-containing precipitate; f) separating said molten lead, containing dissolved noble metals, from said molten mixture; g) adding carbon to said molten mixture to remove lead oxide by converting it to lead and carbon oxides; h) removing said carbon oxides and said lead from said molten mixture to yield a glassy boron oxide fusion melt containing dissolved metal oxides; i) adding said fusion melt to an aqueous nitric acid solution wherein said fusion melt, including said metal oxides in said fusion melt, are rapidly and easily dissolved in said acid solution; j) separating and recovering metals from said acid solution; and k) converting said acid solution into a waste glass. a) providing a bath of molten B.sub.2 O.sub.3 and PbO; b) adding a waste feed material comprising carbon-containing material, halides, and plutonium and uranium in metal or compound form, to said bath to form a molten mixture of dissolution glass and waste; c) oxidizing said waste feed material including said carbon-containing material, plutonium and uranium; d) precipitating molten lead which is formed by said step of oxidizing; e) converting said halides to lead halides which are gases at the temperature of said molten mixture; f) removing said gases to an aqueous scrubber solution of an alkali metal hydroxide, wherein lead hydroxide and alkali metal halides are formed; h) returning said lead hydroxide to said molten mixture; i) adding carbon to said molten mixture to convert said lead oxide to lead and carbon oxides; j) removing said lead from said molten mixture wherein a glassy boron oxide fusion melt containing oxides of plutonium and uranium is formed, said fusion melt being essentially devoid of halides and carbon-containing material; k) solidifying said glassy boron oxide fusion melt; and l) dissolving said fusion melt in nitric acid, and recovering plutonium and uranium. 2. The method of claim 1 wherein said lead-containing precipitate is lead hydroxide and said hydroxide is returned to said molten dissolution glass/waste mixture. 3. The method of claim 1 further comprising processing said lead formed in steps (c) and (g) to separate and recover said noble metals, oxidizing said lead to lead oxide, and returning said lead oxide to said molten dissolution glass/waste mixture. 4. The method of claim 1 further comprising allowing said boron oxide fusion melt to solidify before adding it to said nitric acid solution. 5. The method of claim 1 wherein said waste contains metals or metal compounds of one or more of plutonium, uranium, and rare earths. 6. The method of claim 5 wherein step (j) further comprises separating one or more of plutonium, uranium and rare earths as nitrates, and recovering said plutonium, uranium and rare earths. 7. The method of claim 1 further comprising recovering boron oxide from said boron oxide fusion melt formed in step (h), and reintroducing it into said molten dissolution glass/waste mixture. 8. The method of claim 1 further comprising recovering boron oxide from a boric acid-nitric acid solution formed in step (j), and reintroducing said boron oxide into the glass/waste mixture. 9. The method of claim 6 wherein glass frit is added to a boric acid-nitric acid solution remaining after one or more of said plutonium, uranium and rare earths has been removed, to produce a waste glass suitable for storage or disposal. 10. The method of claim 8 further comprising adding glass frit to said boric acid-nitric acid solution to produce a waste glass suitable for storage or disposal. 11. The method of claim 9 wherein said glass frit is SiO.sub.2, and said waste glass is a borosilicate glass. 12. The method of claim 10 wherein said glass frit is SiO.sub.2, and said waste glass is a non-borosilicate glass. 13. The method of claim 1 wherein said steps (a) through (h) are carried out in a cold-wall glass melter. 14. The method of claim 1 wherein the mole ratio of PbO to B.sub.2 O.sub.3 is 2 to 1. 15. The method of claim 1 wherein said waste contains carbon-containing compounds, and said compounds are oxidized by said dissolution glass to form carbon oxides, and water. 16. The method of claim 5 wherein plutonium and uranium are separated from said acid solution by complexing them with tributylphosphate. 17. The method of claim 5 wherein plutonium and uranium are separated from said acid solution by ion exchange. 18. The method of claim 1 wherein said waste contains plutonium scrap and residue, spent nuclear fuel, and uranium fissile wastes. 19. The method of claim 1 wherein said PbO is present in at least a stoiciometric amount with respect to halogens in said waste material. 20. A method for recovering uranium and plutonium from plutonium residues, spent nuclear fuel, and uranium fissile wastes comprising:
063109301	claims	1. A method of inserting a nuclear fuel bundle having a plurality of fuel rods, a water rod and a plurality of spacers into a fuel bundle channel, comprising the steps of: (a) providing a guide assembly at an open upper end of the channel with guide elements carried thereby spaced above the open upper end of the channel; and (b) lowering the fuel bundle through the guide assembly including engaging the fuel bundle along the guide elements to guide the lower end of the fuel bundle through the channel opening into the channel. 2. A method according to claim 1 wherein the guide assembly includes upper and lower guide members having openings for receiving the fuel bundle and including the step of locating the guide assembly on the top of the channel with the opening through the lower guide member in registration with the channel opening and lowering the fuel bundle through the openings of the guide members into the channel opening. 3. A method according to claim 2 including spacing the guide elements from the lower guide member a distance substantially corresponding to the distance between first and second spacers of the fuel bundle enabling alignment of the first spacer with the channel upon entry of the fuel bundle into the channel opening. 4. A method according to claim 1 including providing visual indicia on the guide assembly to ascertain alignment of the fuel bundle and channel with one another. 5. A method according to claim 1 wherein the guide assembly includes a lower guide member having an opening in registry with the channel opening and including the step of aligning the lower guide member relative to the channel to locate the opening through the lower guide member and channel opening in registration with one another. 6. A method according to claim 5 including providing channel corner locators depending from the lower guide member for engaging corners of the channel to maintain the guide assembly aligned with the channel. 7. A method according to claim 6 including applying shims to said corner locators to obtain accurate alignment of the guide assembly and the channel. 8. A method according to claim 2 including the step of guiding the fuel bundle by engaging fuel rods of the fuel bundle with rollers located between said upper and lower guide members. 9. A method according to claim 8 including biasing said rollers into engagement with comer fuel rods of the fuel bundle and displacing the rollers from their engagement with the comer fuel rods upon engagement of the rollers by the fuel bundle spacers. 10. A method according to claim 1 including performing steps (a) and (b) within a pool at a nuclear reactor site. 11. A method according to claim 1 including performing steps (a) and (b) during initial fabrication of the nuclear fuel bundle prior to use in a nuclear reactor.
062999508	claims	1. A shipping container comprising: 1) an outer container having a wall, a bottom, a dismountable cover and a hollow interior; 2) a liner having sides and a bottom being smaller in every dimension than said outer container; 3) an inner container having a wall, a bottom, a dismountable cover and a hollow interior, said inner container being smaller in every dimension than said liner; and 4) a thermally insulating and energy-absorbing material disposed between said inner container and said outer container in all directions, said thermally insulating and energy-absorbing material consisting essentially of a mixture of 2. A container according to claim 1 wherein that portion of said thermally insulating and energy absorbing material disposed between the cover of said inner container and the cover of said outer container is removable. 3. A shipping container according to claim 1 wherein said thermally insulating and energy absorbing material has a density of approximately 30 pounds per cubic foot. 4. A shipping container according to claim 1 wherein said thermally insulating and energy absorbing material further comprises a component having a high neutron absorption cross section. 5. A shipping container according to claim 4 wherein said component having a high neutron absorption cross section is selected from the group consisting of boron, boron compounds, gadolinium, gadolinium compounds, cadmium, cadmium compounds, europium, europium compounds, hafnium, hafnium compounds, samarium, samarium compounds, and indium alloys. 6. A shipping container according to claim 1 further comprising at least one pressure relief valve in said outer container.
	description	1. Field This invention relates in general to nuclear reactor systems, and, in particular to utility penetrations through a reactor vessel. 2. Description of Related Art In a nuclear reactor for power generation, such as a pressurized water reactor, heat is generated by fission of a nuclear fuel such as enriched uranium, and transferred to a coolant flowing through a reactor core. The core contains elongated nuclear fuel rods mounted in proximity with one another in a fuel assembly structure, through and over which coolant flows. The fuel rods are spaced from one another in co-extensive parallel arrays. Some of the neutrons and other atomic particles released during nuclear decay of the fuel atoms in a given fuel rod pass through the spaces between fuel rods and impinge on the fissile material in adjacent fuel rods, contributing to the nuclear reaction and to the heat generated by the core. Moveable control rods are dispersed through the core to enable control of the overall rate of the fission reaction, by absorbing a portion of the neutrons passing between fuel rods, which otherwise would contribute to the fission reaction. The control rods generally comprise elongated rods of neutron absorbing material and fit into longitudinal openings or guide thimbles in the fuel assemblies running parallel to and between the fuel rods. Inserting a control rod further into the core causes more neutrons to be absorbed without contributing to the fission process in an adjacent fuel rod; and retracting the control rod reduces the extent of neutron absorption and increases the rate of the nuclear reaction and the power output of the core. The control rods are supported in cluster assemblies that are moveable to advance or retract a group of control rods relative to the core. For this purpose, control rod drive mechanisms are provided, typically as part of an upper internal arrangement located, at least in part, within the reactor vessel above the nuclear core. The reactor vessel of the pressurized water reactor is pressurized to a high internal pressure, and the control rod drive mechanisms are housed in part in pressure housings that are tubular extensions of the reactor pressure vessel. FIG. 1 is a schematic view of a prior art nuclear containment 10 housing a nuclear reactor pressure vessel 12 of a conventional pressurized water reactor having a nuclear core 14 supported within the lower half of the pressure vessel 12. A control rod assembly 16, i.e., one of the cluster assemblies, is figuratively shown within the core 14 and supports a cluster of control rods 18 that are moved into and out of the fuel assemblies (not shown) by a drive rod 20. The drive rod 20 is moveably supported by drive rod housing 24 that extends upwardly and through a removable reactor closure head 22. Control rod drive mechanisms (CRDM) are positioned above the reactor head around the control rod drive housings 24 and move the drive rods in a vertical direction to either insert or withdraw the control rods 18 from the fuel assemblies within the core 14. Rod position indicator coils 26 or other indicator mechanisms are positioned around the housing 24 to track the position of the drive rod 20, and thus the control rods 18 relative to the core 14. The output of the position indicator coils 26 is fed through a processor rod position indicator (RPI) electronics cabinet 28 within the containment 10. The output of the rod position indicator electronics cabinet 28 is then fed outside the containment to a logic cabinet 30 and an RPI processing unit 32. The logic cabinet 30 interfaces with the control system 34 which provides manual instructions from a user interface 36 as well as automatic instructions which are generated from intelligence obtained from plant sensors not shown. The logic cabinet 30 receives the manual demand signals from an operator through the user interface 36 and a reactor control system 34 or automatic demand signals from the reactor control system 34 and provides the command signals needed to operate the control rods 18 according to a predetermined schedule. The power cabinet 38 provides a programmed current to operate the CRDM, all in a well known manner. One type of mechanism employed in traditional pressurized water reactors for positioning a control rod assembly 16 is a magnetic jack-type mechanism, operable to move the control drive rod by an incremental distance, of approximately ⅝ inch (1.63 cm), into or out of the core in discrete steps. In one embodiment, the control rod drive mechanism has three electromagnetic coils and armatures or plungers actuated by the electromagnetic coils, that are operated in a coordinated manner to raise and lower the drive rod shaft 20 and a control rod cluster assembly 16, coupled to the drive rod shaft 20. The three coils (CRDM) are mounted around and outside the pressure housing 24. Two of the three coils operate grippers that when powered by the coils engage the drive rod shaft, with one of the grippers being axially stationary and the other axially moveable under the influence of the third coil. In a magnetic jack-type mechanism, the drive rod shaft has axially spaced circumferential grooves that are clasped by latches on the grippers, spaced circumferentially around the drive shaft. The third coil actuates a lift plunger coupled between the moveable grippers and a fixed point. If the power to the control rod mechanism is lost, the two grippers both release and the control rod drops by gravity into their maximum nuclear flux damping position. So long as control rod power remains activated, at least one of the stationary grippers and the moveable grippers hold the drive shaft at all times. The three coils are operated in a timed and coordinated manner ultimately to hold and to move the drive shaft. The stationary grippers and the moveable grippers operate substantially alternately, although during the sequence of movements both types of grippers engage the drive shaft during a change from holding stationary to movement for an advance or retraction. The stationary gripper can hold the drive shaft while the moveable gripper is moved to a new position of engagement. The moveable grippers engage the drive shaft when moving it up or down as controlled by the lift plunger. After the moveable gripper engages the drive shaft, the stationary gripper is released and then the plunger is activated or deactivated to effect movement in one direction or the other. A number of particular coil arrangements and gripper designs are possible, however, whatever mechanical arrangement is employed for the grippers and the lifting coils/armature arrangement, the lifting coils are housed outside the pressure boundary of the reactor vessel where they can be cooled, usually by forced ventilation and are magnetically coupled to the latch assemblies through the pressure housings that surround the drive rods and are vertical extensions of the pressure vessel head. However, one of the next generation of nuclear reactors under development is a small modular reactor that has the core, upper internals, steam generator, pressurizer and inlets and outlets of the primary loop circulation pumps housed within the same pressure vessel. In such an arrangement, the entire control rod drive mechanism is immersed within the reactor coolant, in which the conventional arrangement of coils could not operate reliably. Even if the coils were housed to protect them from direct contact with the coolant, conventional coils could not withstand the temperatures they would experience in an operating cycle. Application Ser. No. 13/314,519, filed Dec. 8, 2011, entitled Nuclear Reactor Internal Control Rod Drive Mechanism Assembly, overcomes those problems, however, the arrangement of components in such small modular reactors preclude the incorporation of vessel penetrations through either the upper or lower vessel heads for routing the cabling needed to power the electromagnetic CRDM coils or other in-vessel instrumentation and controls, the traditional path for supplying electrical power and transporting signals to and from internal components. Typical integral pressurized water reactor designs require that the steam generator be located directly above the reactor core complicating access to the core from above. In addition, in plant designs where in-vessel retention is claimed as a safety feature, bottom vessel penetrations are prohibited thus precluding access to the core through the bottom head. FIGS. 2 and 3 illustrate a schematic of such a small modular reactor. FIG. 2 shows a perspective, partially cut away, to show the pressure vessel and its internal components. FIG. 3 is an enlarged view of the pressure vessel shown in FIG. 2. The pressurizer 54 is integrated into the upper portion of the reactor vessel head and eliminates the need for a separate component. A hot leg riser 56 directs primary coolant from the core 14 to a steam generator 58 which surrounds the hot leg riser 56. Six reactor coolant pumps 60 are circumferentially spaced around the reactor vessel at an elevation near the upper end of the upper internals 62. The reactor coolant pumps are horizontally mounted axial flow canned motor pumps. The reactor core 14 and the upper internals 62, except for their size, are substantially the same as the corresponding components in an AP1000® reactor supplied by Westinghouse Electric Company LLC, Cranberry Township, Pa. From the foregoing, it should be apparent that the traditional means for routing the cabling from internal components to the exterior of the reactor cannot readily be employed. Accordingly, a new cable routing design is desired that will simply transmit electrical power, electrical signals and/or hydraulic fluids from the interior of the reactor vessel to the exterior thereof. Further, such a cable routing scheme is desired that will not impede reactor vessel disassembly and reassembly during plant refueling operations. Additionally, such a cable routing scheme is desired that will facilitate inspection and maintenance of the in-vessel components. These and other objects are achieved by a nuclear reactor having an elongated reactor vessel sealed at a lower end and having an open upper end on which an annular flange is formed and a central axis extending along the elongated dimension. The reactor vessel has a head with an annular portion on the underside of the head machined to form a sealing surface. A removable annular seal ring, sized to seat on the reactor vessel flange between the flange and the sealing surface on the underside of the reactor vessel head, is interposed between the sealing surface on the underside of the vessel head and the flange on the vessel. The seal ring has a thickness that is sized to sealably accommodate radial passages through which utility conduits pass from outside the reactor vessel to an interior thereof to transport one or more utilities comprising hydraulic fluid for hydraulic mechanisms, instrumentation signals or power for electrical mechanisms. The removable annular seal includes one or more of such radial passages. The reactor typically includes an internals assembly having a lower internals which includes a reactive core and an upper internals situated above the core. The internals assembly is seated within the reactor vessel and preferably the removable annular seal ring is attached to the reactor internals assembly. In one embodiment, an annular passage is provided between the interior wall of the reactor vessel and the internals assembly for a downward flow of relatively cool reactor coolant to access an underside of the reactive core, wherein at least a portion of the removable annular seal ring extends over the annual passage where it is attached to the reactor internals assembly. Desirably, in such an arrangement, the portion of the removable annual seal ring that extends over the annual passage includes axially extending openings for the passage of the reactor coolant. Desirably, the axially extending openings are circumferentially spaced from the radial passages. In still another embodiment, the removable annular seal ring is attached to the upper internals and is removable from the reactor vessel with removal of the upper internals. Preferably, in such an arrangement, the utility conduits are an integral part of the upper internals and include a utility disconnect outside the reactor vessel. Preferably, the annual seal ring has an upper and a lower double o-ring seal on opposite sides that mate with the reactor vessel flange on one of the opposite sides and the annular portion of the reactor vessel head on the other of the opposite sides. Desirably, the annular seal ring has a hole extending between the upper and lower double o-ring seals allowing leakage to be detected through both sets of seals through one reactor vessel flange leak-off line. Preferably, the leak-off line extends from the lower double o-ring seal. Preferably, the removable annular seal ring is forged from a metal having substantially the same thermal expansion properties as the reactor vessel. In that regard, the removable annular seal ring may be forged from either (i) carbon steel in which the surfaces in contact with reactor coolant are clad with stainless steel, or (ii) alloy 690. Desirably, the annular seal ring has a plurality of holes axially through the annular seal ring in line with openings in the reactor vessel head and the reactor vessel flange through which studs pass that anchor the head to the flange with the seal ring captured therebetween. Desirably, one or more of the radial passages extend in between two adjacent ones of the holes. Preferably, the utility conduits are sealed to the radial passages on the inner diameter of the seal ring. As previously mentioned, the configuration of some reactor designs, including small, integral, modular reactors, precludes the incorporation of vessel penetrations through either the upper or lower vessel heads for instrumentation and controls. Some small modular reactor designs also require electrical power supply to internal components such as control rod drive mechanism, reactor coolant pumps, and pressurizer heaters. This invention provides an alternative location for all penetrations, including electrical power, through a ring 44 that is clamped between the upper and lower reactor vessel closure flanges 40 and 42, respectively (FIGS. 2 and 3). The preferred embodiment of the invention described herein also provides a convenient means of reactor vessel disassembly and reassembly of the reactor vessel during plant refueling operations and allows for inspection and maintenance of the in-vessel components. The following physical description of the preferred embodiment is specific to a particular small integral reactor design, however, it should be recognized that the novel elements of this invention can be applied to other reactors whether or not they have similar design restrictions. Like reference characters are used among the several drawings to refer to corresponding components. FIG. 4 shows a reactor vessel 12 and its internal components, including the lower internals 46, that includes the core 14, and the upper internals 62, that includes the control rod guide tubes, the drive rod housings 24 and the control rod drive mechanisms (CRDM). This invention provides an annular penetration flange seal 44 with radially extending ports 48 through which utility conduits 50 transport electrical power, instrumentation signals, control signals or hydraulic fluids to or from the interior of the pressure vessel to the exterior thereof. In the preferred embodiment, the penetration flange, or seal ring 44, is a forged ring of either carbon steel (such as SA-508) in which the surfaces in contact with borated reactor coolant are clad with stainless steel or a ring forged from solid alloy 690. These materials have similar thermal expansion properties to the reactor vessel material which is important to the design. The ring 44 is machined to have the necessary detail, such as o-ring retention grooves, to include a double o-ring seal 68 and 70 on both the top and bottom surfaces (FIG. 7). Towards the outside diameter, clearance holes 52 equal to the number of reactor closure studs are machined to allow the studs 74 to pass through the ring 44 (FIGS. 4, 5, 6 and 7). The inner diameter of the ring 44 is secured to the upper internals 62 either through mechanical fasteners or a bi-metallic weld. The utility conduit penetrations 48 through the ring 44 extend radially between the reactor closure stud clearance holes 52. More than one penetration can penetrate through the space between two closure stud holes 52. The arrangement of penetrations will be a function of the requirements of the particular reactor design. In the small modular reactor internals design described herein, flow holes 64 are also required towards the inner diameter of the penetration flange seal ring 44 to allow coolant flow from the steam generator to pass through the penetration flange 44 as best can be seen from FIG. 8. These holes 64 need to be spaced to avoid the radial penetrations 48. The utility conduits, which pass through those penetrations would likely be made from alloy 690, and are sealed on the inner diameter of the penetration ring 44 using a partial penetration J-groove weld 72. The weld 72 forms the primary pressure boundary. From this point, the pressure boundary is maintained by a continuous tube which forms a continuous conduit to the equipment serviced by the utility medium transported through the conduit. The penetration flange 44 could also be used to introduce in-core instrumentation cabling into a thimble tube that can be retracted during refueling by adding a grafoil seal at the penetration. The o-ring seals 68 and 70 can best be observed in FIG. 7 which also shows electrical disconnects 66 on the outside of the reactor which are employed when the internals 62 need to be removed from the vessel to remove the internals 62 with the penetration flange 44. During refueling, the upper internals 62 and the components it supports can be removed from the reactor vessel 12 as a single assembly after the electrical cable terminals 66 have been disconnected. For example, in the case of the small modular reactor described herein, the electrical power and position indication instrumentation cables that service the control rod drive mechanisms all remain attached to the upper internals and can be removed without breaking the pressure boundary within the reactor vessel envelope. To accommodate in-core instrumentation which needs to be retracted from the reactor core during refueling, a mechanical seal can be added to the radial penetration in the penetration flange 44. This seal will allow the instrument to be withdrawn by pulling it through the penetration in the flange. The penetration flange 44 also provides access through the pressure boundary to both relatively hot and cold reactor coolant for temperature measurement. Thermowells can either extend through the outer diameter of the penetration flange 44 to a flow hole 64 to monitor the reactor's cold temperature or through the inside diameter to monitor the reactor's hot temperature. The flow holes 64 in the penetration flange 44 also provide an opportunity for flow measurements. A pitot tube flow probe device can penetrate from the outside diameter into a flow hole 64 to monitor the reactor's coolant flow rate. While specific embodiments of the invention have been described in detail, it will be appreciated by those skilled in the art that various modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular embodiments disclosed are meant to be illustrative only and not limiting as to the scope of the invention which is to be given the full breadth of the appended claims and any and all equivalents thereof.
	abstract	Analysis of the production of 11C fragments mainly by projectile fragmentation of a stable monodirectional and monoenergetic primary 12C beam in different decelerating materials are presented and the optimal target choice have been identified to obtain the highest possible beam quality of decelerated 11C beam at arbitrary energies and therapeutic ranges. The optimal 11C-generating target is made of hydrogen preferably followed by a digitally variable decelerator of a hydrogen rich compound, such as polyethylene, to maximize the quality of the 11C beam.
	abstract	A method for guaranteeing fast reactor core subcriticality under conditions of uncertainty involves, after assembling the reactor core, conducting physical measurements of reactor core subcriticality and comparing the obtained characteristics with design values; then, if there is a discrepancy between the values of the obtained characteristics and the design values, installing adjustable reactivity rods in the reactor at the level of a fuel portion of the reactor core, wherein the level of boron-B10 isotope enrichment of the adjustable reactivity rods is selected to be higher than the level of boron-B10 isotope enrichment of compensating rods of the reactor core. The technical result consists in improving the operating conditions of absorbing elements of a compensating group of rods, eliminating the need for increasing the movement thereof, simplifying monitoring technologies used during production, and simplifying the algorithm for safe reactor control.
	description	This application is a divisional of application Ser. No. 10/844,350, filed May 13, 2004, which is a divisional application of Ser. No. 10/106,895, filed Mar. 27, 2002, which claims priority from Japanese patent application 2001-093306, filed Mar. 28, 2001, and Japanese patent application 2002-046788, filed Feb. 22, 2002. The entire contents of each of the aforementioned applications are incorporated herein by reference. 1. Field of the Invention This invention relates to a device and a method for radiation measurement, applied to monitor the radiation in an extensive range for improving resistance to noises in a digital signal processing. 2. Description of the Related Art As far as radiation measurement is concerned, if wide range radiation is measured, then the pulse measurement method and the Campbell measurement method are often used together. Generally, the pulse measurement method counts the pulse number of a pulse signal from a radiation sensor, but if the pulses overlap and it cannot count by the pulse measurement method, the Campbell measurement method is performed. For example, from six to ten start-up range neutron monitor sensors (SRNM sensors) and from one hundred to two hundred local power range monitor sensors (LPRM sensors) are installed inside of a reactor pressure vessel containing nuclear reactor core to monitor nuclear reactor power. A start-up range neutron monitor and a power range neutron monitor measure outputs of the SRNM sensors and the LPRM sensors, respectively, to monitor the nuclear reactor power in a monitoring range of about eleven figures. In this composition, the start-up range neutron monitor is used to count the pulse number of an output signal of the SRNM sensor in order to monitor relatively low reactor output, that is, the output is in from 10−9% to 10−4% of effective full power of the reactor. This is henceforth called the pulse measurement method. On the other hand, the Campbell measurement method, that is, the measuring of fluctuation power generated due to overlapping of the pulse outputted from the sensor, is used in order to monitor relatively high reactor output, that is, the output is in from 10−5% to 10% of the effective full power of the reactor. Hereafter, a conventional technical example of the pulse measurement method and the Campbell measurement method in a nuclear reactor start-up monitoring system, which is disclosed in Japanese Patent Disclosure (koukai) No. 2000-162366, which is equivalent to U.S. Pat. No. 6,181,761, is explained with reference to FIG. 18. The nuclear reactor start-up monitoring system shown in FIG. 14 is composed of an SRNM sensor 1 for outputting an electric signal containing pulse components corresponding to the number of neutrons in response to neutrons generated in the nuclear reactor, an analog preamplifier 2, an A/D (analog-to-digital) converter 3, and a pulse counter 23, an integration counter 24, a power calculator 25, an arithmetic average calculator 26, and a reactor power monitoring system 27. The analog preamplifier 2 amplifies the electric signal having pulse components outputted from the SRNM sensor 1 to regularize the electric signal, and the A/D converter 3 converts an analog signal outputted from the preamplifier 2 to digital data sampled at intervals which are shorter than a pulse width of the pulse included in electric signal outputted from the SRNM sensor 1. The pulse counter (PC) 23 counts a number of pulses in the sampled data outputted from the A/D converter 3 and converts the number of the pulse to an output level value contained in relatively low range power of the nuclear reactor, and the integration counter 24 adds the sampled valve outputted from the A/D converter 3 to raise the measurement accuracy. The power calculator 25 calculates a power by squaring the added value of the integration counter 24, and the arithmetic average calculator 26 averages the power calculated by the power calculator 25. The reactor power monitoring system 27 continuously monitors the output at the start-up of the nuclear reactor based on the counter result of the pulse counter 23 and the calculation result of the arithmetic average calculator 26. In the digital reactor start-up monitoring system of such a composition, the preamplifier 2 amplifies and regularizes a shape of a pulse included in the electric signal outputted from SRNM sensor 1, and the A/D converter 3 samples the amplified and regularized pulse at high speed and calculates the pulse by using one or more logical operations. Also, the pulse counter 23 counts the calculation results outputted from the A/D converter 3 as an output pulse of the sensor if each calculation result outputted from the A/D converter 3 is in a corresponding predetermined range, respectively. On the other hand, the same sampled value is added in the integration counter 24 to lower into a level of a sampling rating required for the Campbell measurement method and to earn a dynamic range for improving the number of equivalent bits. The power calculator 25 adds square values of the results after performing band-pass-filter process for the results, and the arithmetic average calculator 26 averages the results calculated by the power calculator 25 and computes the Campbell output value. The pulse enumerated data and the Campbell output value are estimated by the nuclear reactor output evaluation unit 27 and are displayed as a nuclear reactor output. In this composition, calculation limited to the sensor-outputting pulse can be carried out with excluding noises having long pulse widths by discrimination based on information of not only a pulse height of a pulse but a pulse width by the pulse calculator 23. That is, in the reactor start-up monitoring system of FIG. 18, for example, the output signal of the SRNM sensor 1 containing a pulse with the pulse width of 100 nanoseconds is sampled at intervals of 25 nanoseconds. Four sampled-data, from data No. k-3 to data No. k, denoted as S(k-3), S(k-2), S(k-1), and S(k) in order, respectively, which correspond to a pulse width, are used to calculation described below, as S(k-3) is a sampled value at a rise point of a pulse, S(k) is a sampled value at a fall point of the pulse, and two sampled data S(k-1), S(k-2) are in between S(k-3) and S(k). It considers a result Out(k) of this calculation as an index of pulse discrimination, and as a result, the pulse is counted as a neutron pulse if it is in a range of predetermined level.Out(k)={bS(k-2)+cS(k-1)}−{aS(k-3)+dS(k)} (1), where a, b, c and d are non-zero constants. By this calculation, it becomes possible to calculate only signals having almost similar pulse widths as that of the output pulse of the SRNM sensor 1. That is, even if a large surge-like noise becomes overlapped on a signal pulse, it can count measured value exactly by deducting the ground level of the pulse. In addition, by setting two or more indices such as the Out(k) for detecting a case corresponding to such a sensor pulse form as mentioned above and using AND logic among these indices, this discrimination performance can be improved further. Thus, even if a surge-like noise with a pulse width of several microseconds overlaps, and is supposed to be guided into a pulse in an electric signal outputted from the SRNM sensor most easily, the surge-like noise can be removed nearly completely and a limited calculation of sensor pulses with a pulse width of about 100 nanoseconds can be performed. On the other hand, in the Campbell measurement method, the power calculator 25 restricts a frequency band and calculates an average of square values of the sampled data. In this composition, since the frequency band can be set up by software programming, if a noise is in a certain frequency equivalent to a measurement band, changing the measurement band on the software programming can reduce guidance of the noise. However, there are several subjects described below in the nuclear reactor start-up monitoring system according to the above-mentioned conventional technology. A first subject concerns reduction of a bipolar noise. That is, if surge noise with a pulse width of several microseconds and sensor output pulse overlap, it is necessary to compute a value corresponding to a pulse peak value by using the difference between them in order to count the overlapped sensor output pulse without preparing dead time. In taking the difference, if the pulse is homopolar, that is, either a positive pulse or a negative pulse, such as a sensor output pulse, a pulse discrimination level of the pulse is equivalent to a conventional pulse peak value from the ground level. However, if the pulse is bipolar, such as a white noise from a circuit resistance, it is necessary to discriminate voltage between peaks of the pulse from the pulse discrimination level. For this reason, the discrimination level necessary in this case is twice as much as that of conventional discrimination method using pulse peak from ground level. Therefore, the discrimination level required to count the sensor output limitedly is needed about twice as much as that of the conventional method, and thus the ratio of sensor signal to white noise, that is, the signal-to-noise ratio (S/N ratio), worsens. A second subject concerns improvement of resistance to noises in the Campbell measurement method. Conventional noise test of a motor, for example, shows that a surge noise with a pulse width of several microseconds is easily induced to the reactor start-up monitoring system. In the pulse measurement method, this surge noise can be reduced by pulse discrimination according to the above-mentioned digital calculation. On the other hand, in the Campbell measurement method, a measurement band is set as a frequency band from several hundreds of hertz to one megahertz, which is selected according to a form of a sensor output pulse, and in the above-mentioned precedence example, the induction noise is removed by shifting this measurement band. However, since the frequency of the noise that is the easiest to be guided mostly falls in a range of the measurement band, it is difficult to remove the noise completely, and it is necessary to rectify sensor sensitivity because the sensitivity changes slightly. Generally, a measurement device for measuring dose equivalent is optimized in a radiation incidence window, reaction volume, etc., of a sensor, so that sensitivity characteristics over gamma ray energy of the device may become equal to energy absorption characteristics of a human body. However, it is difficult to make the sensitivity characteristics in agreement correct because the sensitivity characteristics differ according to directions of incidence of gamma rays. Moreover, as far as accurate conversion of the dose equivalent to a human body is concerned, since energy absorption characteristics differ according to parts of a human body, it is difficult for independent use of the measurement device modified to equalize to the sensor sensitivity over gamma ray energy to evaluate the dose equivalent in each part of a human body. Furthermore, when neutrons other than of a gamma ray, such as a beta ray, are intermingled, a sensor that has rectified its sensitivity by arranging sensor structure cannot estimate such mingled radiations, each of which has absorption characteristics which are greatly different from that of another radiation. Therefore, it must arrange a plurality of measurement systems each of which is used for measuring one radiation exclusively. Conventionally, in order to solve these subjects, it is proposed and put in practical use to compute energy spectrum of a gamma ray to be converted to the dose equivalent. However, since this technique is based on acquisition of energy information by using pulse height, in a condition in which pileup of pulses is occurred, it becomes difficult to acquire the energy information and thus the accuracy of this technique worsens. That is, although depending on a pulse width of a sensor output pulse, a maximum of conventional energy measurement is about 1105 counts per second (CPS). If it is supposed that a minimum of the measurement is one CPS, which must satisfy a response demand, a measurement range goes into about 5 figures. Thus, it is desired to realize a measurement method which enables to measure a dosage in more extensive range continuously. Japanese Patent Disclosure (koukai) No. H3-183983 shows that dual structure of sensors in a radiation measurement device for measuring dose equivalent in depth of one centimeter improves measurement precision. In this technique, the above-mentioned pileup influence in the pulse measurement method is evaded by means of measuring current. However, sensor structure and processing in this technique are complicated, thus it is desired that they be simplified. Accordingly, an object of this invention is to provide a device and a method for measuring radiation which improves noise resistance in the pulse measurement method and the Campbell measurement method using digital processing. Another object of this invention is to provide a device and a method of radiation measurement which monitors a dosage in a wide range continuously with a convenient composition by applying the Campbell measurement method to the measurement of a radiation dosage. Additional purposes and advantages of the invention will be apparent to persons skilled in this field from the following description, or may be learned by practice of the invention. According to an aspect of this invention, there is provided a device for measuring radiation, including a radiation detector which generates an analog signal containing pulse components corresponding to a dosage of an inputted radiation, an A/D converter which regularizes the analog signal outputted from the radiation detector and converts the regularized analog signal into sampled data, an n-th power pulse discrimination unit which calculates an n-th power value for each of the sampled data outputted from the A/D converter and discriminates the pulse components contained in the analog signal of the radiation based on the calculated n-th power values to generate a discrimination signal associated with each discriminated pulse component, where n is an integer of not less than two, and a pulse counter which counts a number of the discriminated pulse components based on the discrimination signal outputted from the n-th power discrimination unit. According to another aspect of this invention, there is provided a device for measuring radiation, including a radiation detector which generates an analog signal containing pulse components corresponding to a dosage of an inputted radiation, an A/D converter which regularizes the analog signal outputted from the radiation detector and converts the regularized analog signal into sampled data, a band pass filter which limits the sampled data outputted from the A/D converter within a predetermined frequency band to generate restricted sampled data, an n-th power calculation unit which calculates the n-th power values of the restricted sampled data outputted from the band pass filter, where n is an integer of not less than two, a first smoothing unit which equalizes the n-th power values of the limited sampled data outputted from the n-th power calculation unit within a first time width to generate a first smoothed n-th power value, a data removal equalization unit which evaluates sizes of the first smoothed n-th power values outputted from the first smoothing unit within a second time width, removes a predetermined data removal number of the first smoothed n-th power values based on the evaluation result, and equalizes the first smoothed n-th power values after the removing within the second time width to generate a second smoothed n-th power value, a second smoothing unit which equalizes the equalized n-th power values outputted from the data removal and equalization unit to generate a third smoothed n-th power value, and a converter which converts the second smoothed n-th power value outputted from the second smoothing unit into a radiation intensity of the inputted radiation. According to still another aspect of this invention, there is provided a device for measuring radiation, including a radiation detector which generates an analog signal containing pulse components corresponding to a dosage of an inputted radiation, an n-th moment calculation unit which calculates an average value of the n-th power values of pulse heights within a time width as an n-th moment value based on the analog signal outputted from the radiation detector, where n is an integer of not less than two, and where the pulse heights correspond to the pulse components included in the analog signal, a pulse counter which counts a number of pulse components based on the analog signal outputted from the radiation detector, an average energy calculation unit which calculates an average energy of the radiation based on a ratio of the n-th moment value calculated by the n-th moment calculation unit to the number of the pulse components counted by the pulse counter. According to still another aspect of this invention, there is provided a device for measuring radiation, including a radiation detector which generates an analog signal containing pulse components corresponding to a dosage of an inputted radiation, an n-th moment calculation unit which calculates an average value of the n-th power values of pulse heights within a time width as an n-th moment value based on the analog signal outputted from the radiation detector, where n is an integer of not less than two, and where the pulse heights correspond to the pulse components included in the analog signal, a current measurement instrument which calculates an average current from the pulse heights of the pulse components included in the analog signal, and an average energy calculation unit which calculates an average energy of the radiation based on a ratio of the n-th moment value calculated by the n-th moment calculation unit to the average current calculated by the current measurement instrument. According to still another aspect of this invention, there is provided a device for measuring radiation, including a radiation detector which generates an analog signal containing pulse components corresponding to a dosage of an inputted radiation, first to n-th moment calculation units each calculating an average value of one of first to n-th power values of pulse heights corresponding to the pulse components included in the analog signal within a time width as one of first to n-th moment values, respectively, where n is an integer of not less than three, and an average energy calculation unit which calculates an average energy of the radiation based on a ratio of two of the first to n-th power values calculated by the first to n-th moment calculation units, respectively. According to still another aspect of this invention, there is provided a method of measuring radiation, including A/D converting an analog signal containing pulse components corresponding to a dosage of an inputted radiation outputted from a radiation detector into sampled data, calculating n-th power values of the sampled data, where n is an integer of not less than two, and discriminating the pulse components of the radiation contained in the analog signal based on the n-th power values of the sampled data. According to still another aspect of this invention, there is provided a method of measuring radiation, including A/D converting an analog signal containing pulse components corresponding to a dosage of an inputted radiation outputted from a radiation detector into sampled data, calculating n-th power values of the sampled data, where n is an integer of not less than two, equalizing the n-th power values of the sampled data within a time width; and discriminating the pulse components of the radiation contained in the analog signal based on the equalized n-th power values of the sampled data. According to still another aspect of this invention, there is provided a method of measuring radiation, including calculating an average value of n-th power values of pulse heights of pulse components corresponding to a dosage of an inputted radiation included in an analog signal outputted from a radiation detector within a time width, where n is an integer of not less than two; and calculating at least one of a radiation intensity of the inputted radiation and a dosage equivalent of the inputted radiation based on the average value. Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, the embodiments of this invention will be described below. A radiation measurement device of a first embodiment in this invention is explained with reference to FIG. 1. The radiation measurement device shown in FIG. 1 is composed of an SRNM sensor 1 for generating an electric signal containing pulse components according to a radiation dosage in response to an inputted radiation, a preamplifier 2A for amplifying the output pulse, an A/D converter 3 for sampling the output pulse of the preamplifier 2A at intervals of time shorter than pulse duration of the output pulse to obtain sampled data, an n-th power pulse discrimination unit 4, and a pulse counter 5. The n-th power discrimination unit 4 is provided to calculate an n-th power value of the sampled data, corresponding to the pulse duration of the pulse from the SRNM sensor, and to discriminate a signal by comparing the calculated n-th power valve with a predetermined discrimination level. And the pulse counter 5 counts a pulse discriminated by the n-th power discrimination unit 4. The SRNM sensor 1 is a nuclear fission sensor for outputting a signal containing pulse components, and it can also replace the sensor by an ionization chamber from which same kind of the pulse output of the SRNM sensor is obtained. In such a composition, when neutrons are injected into the SRNM sensor 1 of this radiation measurement device and nuclear fission is occurred in the sensor 1, an electric analog signal containing pulse components as shown in FIG. 2(a) is outputted from the SRNM sensor. A pulse width of the pulse in this signal outputted from the SRNM sensor 1 is about 100 nanoseconds. This output signal is inputted into the preamplifier 2A and the pulse is amplified. The preamplifier 2A also has a function to impress an operating voltage to the SRNM sensor 1. The signal with pulse components outputted from the preamplifier 2A is inputted into the A/D converter 3, and is sampled at sampling time intervals to be digitalized, as sampled data are shown by dots in FIG. 2(a). The shorter these sampling time intervals are, the more information about waveforms can be extracted, and if these sampling time intervals are sufficiently short, it is possible to count only the output pulse of the sensor correctly with excluding a signal due to an incoming foreign noise. The A/D converter 3 also performs band-pass-filter processing for restricting to a frequency band which is necessary in the sampling theorem before the sampling of data. The sampled data outputted from the A/D converter 3 is inputted into an n-th power calculation unit in the n-th power pulse discrimination unit 4 to calculate the n-th power value of the data. That is, the n-th power calculation unit calculates an n-th power value of each sampled data, or multiplies by n pieces of sampled data which are placed sequentially. Here, n is an integer of not less than two. In case of calculating the n-th power value of each sampled data, it also performs equalization processing of two n-th power values placed sequentially. For example, when a pulse waveform is sampled at eight pieces, it performs equalization processing of two pieces of data placed sequentially after the calculating of each square value of each data, and consequently four values are acquired. In this case, it is also possible to perform moving-average processing to acquire eight pieces of sampled data. FIG. 2(b) shows a trend of sampled data when performing square value calculation in a case that n is two, as one example. By transforming each sampled data into a square value, a pulse height ratio of the sensor output pulse to a noise component due to the circuit resistance can be improved to n-th power times as much as that of the conventional method. However, when it uses values acquired by simple calculation of the n-th power value of every sampled data for pulse discrimination, the discrimination performance is the same as that in a case the sampled data is used for the pulse discrimination without calculation. Then, when calculating of the n-th power value in the digital operation, it is surely necessary to add a processing of multiplication of several pieces of data placed sequentially or a processing of equalization of the several pieces of data placed sequentially, after the n-th power calculation, as already stated. By comparing the calculation result acquired by this square calculation with a predetermined discrimination level, which has a minimum and a maximum, and recognizing the result comes from a sensor output pulse when the calculation result is within the predetermined discrimination level, it becomes easier to discriminate an output pulse of the SRNM sensor 1 from a coming foreign circuit noise. By this radiation measurement device, a pulse discriminated by an output of the SRNM sensor 1 is converted into a pulse generating rate in the pulse counter 6, and is finally converted to a neutron flex level in a position of the SRNM sensor 1. According to this embodiment of the invention, it can discriminate a pulse which has a pulse height of the same grade as a circuit noise level better than the conventional method calculating a difference. FIG. 3(a) shows an example of sampling of an amplified electric signal containing a white noise, which is one of foreign noise due to a circuit resistance with a relatively short pulse width, and a sensor output pulse outputted from the SRNM sensor 1 with a pulse height of the same grade as that of the white noise by A/D converter 3. FIG. 3(a) shows a case that a sensor output pulse is generated at around 4.20103 nanoseconds, and in a section between two vertical dashed lines the sensor output pulse is overlapped with the white noise. And in an area other than this section, there is no sensor output pulse. Suppose that a horizontal dashed line Lb in FIG. 3(a) denotes a maximum of a discrimination level, if the conventional noise discrimination by a pulse height is performed to these data, one pulse at around 4.20103 nanoseconds including a white noise and a sensor output pulse is included in the discrimination level and another one pulse-like portion at around 4.05103 nanoseconds including a white noise and no sensor output pulse is also included in the discrimination level, thus the pulse counter counts both the pulse and the pulse-like portion. That is, as a result, a portion in which no output signal occurs is also counted, so in this method it cannot carry out an exact measurement. Moreover, in the above-mentioned pulse count method using a difference between sampled data values, if a circuit noise is generated as a bipolar noise with both positive and negative components, a voltage difference between a positive peak and a negative peak of the bipolar noise in a certain time width is recognized as a pulse height in this time width. Thus, it cannot discriminate the circuit noise unless it raises a discrimination level to twice the voltage as that in the conventional discrimination method by seeking a pulse height value from zero volt. On the other hand, FIG. 3(b) shows a calculation result of the sampled data shown in FIG. 3(a) acquired by a conventional method for calculating an arithmetical mean among three values lined sequentially. By calculating an arithmetic average, positive and negative components of the bipolar noise are cancelled and equalized. However, as far as a homopolar sensor output signal is concerned, it has originally one of a positive component and a negative component; thus the above-mentioned cancellation cannot be cancelled and the pulse width of the calculation result of data of such a homopolar signal becomes longer as shown in FIG. 3(b). While the pulse width becomes longer, in a condition in which there are a lot of output pulses included in a signal outputted from the sensor, there is a possibility where the pulses may overlap and the counting of a number of the pulses cannot be performed correctly and an upper count limit of the pulse measurement becomes lowered. FIG. 3(c) shows a calculation result of the sampled data shown in FIG. 3(a) in the n-th power pulse discrimination unit 4 in this embodiment, here, for example, by calculating the square values of the sampled data values and afterward calculating an arithmetic average of three sequentially-lined square values. By comparing a surrounded portion of two vertical dashed lines, including both the white noise and the sensor output pulse, with another portion left of the surrounded portion, it is found that calculated values in the surrounded portion definitely differ from calculated values in the another portion, thus the discrimination can be performed. That is, by setting a minimum of the discrimination level relatively close to zero, for example, around 110−4 volt2, the pulse counter can count only the sensor output pulse, therefore, in this method, the discrimination performance can be improved from the conventional method calculating differences. Moreover, compared with the conventional method as shown in FIG. 3(b), after the calculation, a pulse width composed of the calculated values is not prolonged comparatively; therefore, it can measure the pluses without worsening the upper count limit of the pulse. If n is an odd integer in this embodiment, the above-mentioned method can equalize while maintaining signs of the bipolar noise; therefore and a homopolar signal can be discriminated from a bipolar noise signal with a good signal-to-noise ratio. Therefore, in this embodiment, in setting a discrimination level of an output pulse, the discrimination level for removing a circuit noise or an alpha ray noise is set relatively low, and accordingly, even if the sensor output pulse is small, the pulse can be measured without lowering the measure sensitivity. A second embodiment according to this invention is explained with reference to FIG. 4. In this embodiment, an n-th power pulse discrimination unit 4 of the radiation measurement device shown in FIG. 4 is composed of an integration discrimination unit 6, a difference discrimination unit 6, and a pulse height and power discrimination unit 8. An output of A/D converter 3 composed of the sampled data values is inputted into the integration discrimination unit 6, a difference discrimination unit 7, and outputs of these units 6, 7 are imputed to a pulse height and power discrimination unit 8. An output signal of the pulse height and power discrimination unit 8 is inputted into a pulse counter 5. Here, in the integration discrimination unit 6, the pulse is discriminated according to the pulse discrimination method as explained in the first embodiment. That is, the integration discrimination unit 6 of the n-th power discrimination unit calculates the n-th power value of the sampled data values, and judges whether there is a sensor output pulse or not by comparing the n-th power values or arithmetic averages of every sequential n-th power values with a predetermined discrimination level. A first example of discrimination method of the difference discrimination unit 7 in this embodiment is explained according to the following principle. Suppose that the maximum value and the bottom value of an output of the A/D converter 3 are denoted as Top(k) and Bottom(k), respectively, namely:Top(k)=bS(k-2)+cS(k-1),Bottom(k)=aS(k-3)+dS(k), where a, b, c and d are non-zero constants. Then, the pulse height value High(k) in the above-mentioned conventional formula (1) can be denoted to be simplified as:High(k)=+Top(k)−Bottom(k). In this example of this embodiment, firstly, it calculates a difference of a square value of a top value Top(k) and a square value of a bottom value Bottom(k), which is hereafter denoted as X, is calculated, namely: X = + Top ⁡ ( k ) 2 - Bottom ⁡ ( k ) 2 = ( Top ⁡ ( k ) - Bottom ⁡ ( k ) ) ⋆ ( Top ⁡ ( k ) + Bottom ⁡ ( k ) ) = High ⁡ ( k ) ⋆ ( Top ⁡ ( k ) + Bottom ⁡ ( k ) ) ( 2 ) Here, when a sensor output signal pulse is superimposed only on a usual circuit noise such as a white noise (hereinafter it is called Case 1), Top(k) is extremely larger than Bottom(k); therefore the formula (2) can be replaced to an approximate formula such as:X=High(k)Top(k) (3). On the other hand, when the signal pulse is superimposed on an extremely large surge noise (hereinafter called Case 2), Top(k) equals approximately Bottom(k) as an approximation; thus, the formula (2) can be expressed with an approximate formula such as:X=High(k)(2Top(k)) (4). Thus, from the formulas (3) and (4), it holds the relation as:X/Top(k)=αHigh(k) (5), Provided a is either one or two, that is, α equals one in Case 1 and a equals two in Case 2; therefore, the value X/Top(k) mostly serves as a linear function of the pulse height High(k). That is, even when the output pulse of the SRNM sensor is overlapped on the surge noise, it becomes possible to discriminate and calculate the SRNM sensor output pulse of several hundreds of nanoseconds which overlapped on the surge noise with a cycle of several microseconds, by the discrimination comparing the above-mentioned value X divided by Top(k) with a predetermined discrimination level. Thus, according to this first example of the second embodiment, even if a foreign noise with a pulse width longer than that of the sensor pulse is induced, the influence due to the foreign noise can be reduced by the discrimination using difference of the n-th power values. Next, a second example of discrimination method of the difference discrimination unit 7 in this embodiment is explained according to the following principle. In the formula (1), say,D1(k)=cS(k-1)−dS(k) (6),D2(k)=−αS(k-3)+bS(k-2) (7). Thus, the peak value High (k) is denoted as follows:High(k)=+D1(k)+D2(k) (8). The sum of the n-th power values of each member in the right side of the equation (8), denoted as Y hereinafter, isY=D1(k)n+D2(k)n. And this formula is deformed, as an approximation, to the following:Y=High(k)n. That is,Y−n=High(k). Thus, in this case, the pulse discrimination is possible by calculating the value Y−n as an approximate index for comparing with a predetermined discrimination level. In addition, it is equivalent to a formula (1) when n=1 in this case. As mentioned above, even when the output pulse of the SRNM sensor 1 is overlapped on a surge-like noise, it is possible to discriminate and calculate the output pulse of the SRNM sensor 1 for several hundreds of nanoseconds which overlapped on the surge noise with a cycle of several microseconds by using the index acquired by calculating the difference. As mentioned in the first embodiment, for counting a number of pulses, the integration discrimination unit 6 is effective in excluding influence of bipolar noises, such as a white noise, having an incoming interval shorter than the pulse duration of the sensor output, and is also effective in excluding influence of noises with pulse components having pulse heights smaller than that of the sensor output pulse, for example, a circuit noise or an alpha ray noise of the sensor. On the other hand, the difference discrimination unit 7 is effective to noises having a cycle longer than pulse duration of an output pulse of the SRNM sensor 1, and in general it is also effective to remove foreign induced noises having a pulse duration of several microseconds. Therefore, by adjusting logics of these units most suitable, respectively, it can calculate the sensor output only by counting the pulse only when conditions of these units are both effected. As mentioned above, according to the first example and the second example of this second embodiment, by using an n-th power value of a difference of the sampled data corresponding to a pulse height, the influence due to foreign noises with a pulse width longer than that of the sensor output pulse can be reduced, and thus it becomes possible to perform radiation measurement with higher accuracy, as well as the first example of the second embodiment. Next, a composition of the pulse height and power discrimination unit 8 is explained as a third example of this embodiment. The pulse height and power discrimination unit 8 receives an integral value of a pulse from the integration discrimination unit 6 and a value corresponding to a pulse height value of a pulse from the difference discrimination unit 7. A ratio of these values, that is, an integral value divided by the pulse height value, is mostly shown as a certain fixed value equivalent to a pulse width when the pulse is a sensor output pulse. On the other hand, since the white noise containing a high frequency component has a small integration value even if the pulse height value of the noise is equivalent to a sensor output pulse, this ratio of the white noise becomes small. Moreover, since the surge noise with a long pulse width has a large integration value and a small pulse height value, this ratio of the surge noise becomes larger than that of the sensor output. Therefore, by calculating this ratio in the pulse height and power discrimination unit 8 and setting the pulse counter 5 for counting as a pulse when this ratio is within a predetermined certain range, the influence due to these noises can be reduced. As mentioned above, in this pulse measurement method, even if a surge-like foreign noise is induced, when the surge-like noise has a cycle of several microseconds, which is longer than pulse duration of the sensor output pulse, that is 100 nanoseconds, the influence due to the surge-like noise can be eliminated and it can also count pulses overlapped on the noise. Thus, according to this third example of this embodiment, by using both the pulse calculation method using the difference mentioned in the first or the second example of this embodiment and the pulse calculation method using the n-th power value mentioned in the first embodiment, it can measure pulses accurately with accompanying characteristics of the both methods. Next, a third embodiment in this invention is explained with reference to FIG. 6. A radiation measurement device of the third embodiment shown in FIG. 6 is characterized as a homopolar conversion unit 9 for converting a bipolar signal into a homopolar signal, which is either a non-negative signal or a non-positive signal, according to the polarity of a main component of a pulse contained in an inputted signal, and which is arranged between the A/D converter 3 and the n-th power pulse discrimination unit 4 in the first embodiment of this invention shown in FIG. 1. In addition, like the first embodiment, although the SRNM detector 1 is a nuclear fission detector from which a pulse output is acquired, radiation detectors, such as an ionization chamber from which the other pulse outputs can be acquired, can be applied to the detector instead of the SRNM detector 1 in this embodiment. In this embodiment of such a constitution, a function of the homopolar conversion unit 9 is explained with reference to FIG. 7. FIG. 7(a) shows an example of a pulse waveform when performing secondary differentiation processing to a sensor utput, such as a pulse shown in FIG. 2(a). In this embodiment, it is possible to construct the secondary differentiation processing by processing in an analog circuit in the preamplifier 2, or by digitally processing the secondary differentiation calculation to data sampled by the A/D converter 3, both of which are available. A result of average processing after n-th power calculation of the waveform shown in FIG. 7(a), where n is an even number, such as two, by the n-th power pulse discrimination unit 4 is shown in FIG. 7(b). In this calculation, since the bipolar waveform is changed to a homopolar (non-negative) waveform by setting n as an even number, the pulse duration is prolonged. Then, since the main component of the pulse shown in FIG. 7(a) is negative, where the lower direction means negative in FIG. 7(a), the homopolar conversion unit 9 of this embodiment replaces the positive component of the signal shown in FIG. 7(a) with zero or a certain negative value close to zero, and converts to the waveform as shown in FIG. 7(c). A result of average processing after n-th power calculation of this waveform shown in FIG. 7(c), where n is an even number, such as two, is shown in FIG. 7(d). It is possible to narrow a spread of the pulse width compared with a case of FIG. 7(b) without using this homopolar conversion unit 9. Therefore, in this embodiment, even when n is an even number, the pulse width is not prolonged, and thus it is possible to reduce incorrect counting due to pulse pileup which blocks to count one pulse by overlapping of pulses, and prevent a reduction in the measurement minimum of the pulse measurement. Next, a fifth embodiment of this invention is explained with reference to FIG. 15. A radiation measurement device of this embodiment shown in FIG. 15 has a CdTe sensor 16 using CdTe (cadmium, tellurium) which is a room-temperature semiconductor, as a radiation sensor. As a radiation sensor, it is also possible to use a combination of a scintillation sensor, such as NaI, and photomultiplier tubes that enable to acquire energy information, or a Ge (germanium) sensor as a semiconductor sensor. The output of the CdTe sensor 16 is inputted into a charge amplifier (CA) 17. And this charge amplifier 17 integrates electric charge of pulse components included in an input signal and converts to a pulse having a pulse height based on the amount of the electric charges to be outputted. In addition, the charge amplifier 17 supplies operating voltage to the CdTe sensor 16. An output of the charge amplifier 17 is transformed in waveform by such as a pileup rejection circuit or a pole zero cancellation circuit, which are generally used for measuring radiation energy, and afterward it is inputted to an MSV measurement unit 18, a current detector (CD) 19 and a pulse counter (PC) 20. In the MSV measurement unit 18, after restricting a frequency band, it averages the n-th powers and the average is converted to an MSV measurement value, i.e., a secondary moment value. The current detector 19 measures an average current value, which is a primary moment value, and the pulse counter 20 calculates a pulse number. The MSV measurement value, the current measurement value, and the pulse enumerated number are inputted into an energy evaluation unit 21, respectively, and the energy evaluation unit 21 evaluates average radiation energy based on a ratio of the MSV value to the number of pulses or a ratio of MSV value to the direct current value, that is, a ratio of the secondary moment and the primary moment. This average energy value and the above-mentioned measured values are inputted into a dosage evaluation unit 22, and thus they are converted to an irradiation dose, or an absorbed dose in a substance, or a dose equivalent including a risk rate to a human body. The output of the charge amplifier 17 is a pulse having a peak value proportional to a radiation energy absorbed in the CdTe sensor 16. Therefore, suppose that a probability where the reaction occurs is N and the absorption energy is q, the MSV value, the pulse enumerated number and the current value can be approximated by the following formulas: MSV value: k1q2N, n-th moment value: knqnN, Pulse enumerated number: k2N, and Direct current value (primary moment value): k0qN, Here, k0, k1, k2 and kn are compensation coefficients, respectively. And their ratios are: MSV value/pulse enumerated number=k1q2 (generally, knqn), MSV value/direct-current value=(k1/k0)q, and n-th moment value/n′ moment value=knqn-n′/kn′. Therefore, it can presume the absorption energy in a crystal by evaluating these compensation coefficients k0, k1, k2 and kn, etc., beforehand and using ratios of these measured values. FIG. 16 is a plotted graph showing a relation of the pulse enumerated number and the MSV value (shown in a vertical axis) and a dosage (shown in a horizontal axis) measured by a commercial radiation surveymeter when it measures radiations of various radioactive elements, that is, radiations having different energy respectively, by the CdTe sensor 16. Generally, the surveymeter, etc., is adjusted in internal compensation coefficients or shielded, so that sensitivity characteristics to the radiation energy agree with an evaluation curve of the dose equivalent to the radiation energy. That is, although a pulse counting rate becomes large to a radiation having low energy since its absorption energy when one radiation is irradiated is low, the dosage of one radiation in this case becomes low. On the contrary, although a pulse counting rate becomes low to a radiation having high energy, the dosage becomes large since an amount of electric charges generated by one radiation is large. Thus, it is adjusted by shielding, etc., so that the pulse counting number or the current value sensitivity becomes the same as a contribution rate to the dose equivalent. Since the case shown in FIG. 16 omits this sensitivity compensation, the pulse enumerated number is large in a radiation with low energy, and the pulse enumerated number and the MSV measurement value become random to the dose equivalent. However, if it is plotted as characteristics to the dosage of a ratio of the MSV value to the pulse enumerated number, as shown in FIG. 11, it becomes monotonous characteristics to the dose equivalent. Thus, it is possible to convert the ratio of these to the dose equivalent by evaluating these characteristics in advance. Similarly, since the ratio of the MSV value to the pulse enumerated number serves also as monotonous characteristics to incident energy, it is possible to presume average incident radiation energy by evaluating these characteristics in advance. In this case, it becomes possible to evaluate an absorbed dosage at each part of a human body to the radiation energy more accurately by using absorption characteristics of the part of a human body. Furthermore, there are two cases to evaluate the dosage by the pulse measurement. One case is a method for converting energy information of the incident radiation acquired by measuring a pulse height distribution of the pulse to the dosage, and another case is a method for equalizing the sensitivity of the pulse measurement and dosage response characteristics by devising structure itself of the above-mentioned sensor. Moreover, as a way of evaluating the dosage by the current value, there is a method of adjusting a sensitivity response by the devising the sensor structure mentioned as the latter method of the above-mentioned cases. Therefore, it can perform still more accurate dosage evaluation by using both these common techniques and the dosage evaluation method in this embodiment. That is, for example, if it uses the evaluated compensation function in this embodiment after adjusting the sensitivity characteristics of the sensor to some extent independently, it becomes possible to perform still more exact dosage evaluation. Furthermore, if the pulse is piled up in a high counting rate with dropout count, it cannot evaluate an accurate dosage by the method of converting the acquired pulse height information into the dosage mentioned as the former method of the above-mentioned cases. And in the latter shielding method of the above-mentioned cases, it must rectify a number of the dropout count. However, in this embodiment, it is possible to evaluate the dosage in the MSV measurement and measure in a large range by performing the pulse measurement and the MSV measurement simultaneously, even when the pulse measurement is saturated by the pileup. Although it needs to rectify the pileup effect of the pulse measurement in the presumption of the average energy in this case, the error can be suppressed in a range which can be neglected by making the sensitivity of the sensor itself approximate to the dosage response to some extent. Moreover, if it uses a ratio of the current value to the pulse enumerated number or a ratio of the MSV value to the current value, as well as the ratio of the MSV value to the pulse enumerated value, it can presume the average radiation energy by acquiring a compensation function similar to that of the case mentioned above. In this way, according to this embodiment, by using both the n-th moment value and the pulse measurement together, it can evaluate the dosage accurately based on the presumption of the average incident energy. Moreover, even if it is in a condition occurring counting error due to the pileup of the pulses, by using the ratio of the n-th moment to another n-th moment, it can presume the average energy similarly, and the dosage evaluation is carried out exactly in a measurement range larger than that of the conventional method. Furthermore, hereinafter it explains a deformed example of this embodiment. Here it can presume energy distribution by calculating the first power value, that is an average current, and the second value, the third value, etc., and the n-th power value, instead of the MSV value, and calculating a compensation function of each value, respectively, and solving a reverse matrix of each compensation function, respectively. That is, the measurement value of each n-th moment can be expressed as follows:x1=a1[1:n]E[n:1], (equivalent to the current measurement value)x2=a2[1:n]E[n:1], (equivalent to the MSV measurement value)x3=a3[1:n]E[n:1], . . . ,xn=an[1:n]E[n:1], wherein, xk: k-th moment value [scalar quantity], ak: Response matrix [matrix with one line and n columns], E: Energy distribution [matrix with n lines and one column]. Here, it can denote the relation of the matrices X and E by using a matrix A with n lines and n columns, as follows:X[n:1]=A[n:n]E[n:1]. Thus, the radiation energy distribution can be acquired by solving a reverse matrix of the matrix A, such as:E[n:1]=A−1[n:n]X[n:1]. However, in this moment measurement from the first power to the n-th power, it is sufficient to select the number of the moments corresponding to a necessary energy bandwidth from the above-mentioned formulas, and it can consist only of alternating current measurement means by removing the average current value as the first moment among the moment values. As mentioned above, by combining the MSV measurement and one of the pulse measurement and the current measurement, it can presume the average radiation energy by the ratio and convert it to the dosage. This can easily realize characteristics which are more similar to the dosage response by using together with a conventional technique of rectifying the sensitivity by changing the sensor structure. Moreover, it is not necessary to sort out the pulse height for realizing with easy composition, compared with the conventional technique of computed the dosage by questing the pulse height. Furthermore, it can reconstruct the radiation energy by using two or more n-th moment values, and it can measure the radiation energy distribution even in the case of high counting rate making the pulse measurement difficult, and evaluate the dosage more accurately from this information. In this way, by using this method independently or combined with the conventional dosage evaluation method, it can provide a radiation measurement device for collectively monitoring in a wider range more exactly. As explained above, according to the radiation measurement device of the above-mentioned embodiments in this invention, it can reduce a bipolar circuit noise with a small signal level and an alpha ray noise of the sensor and a ratio of these noises to the sensor pulse, by calculating the n-th power values of the pulse waveform and discriminating with the values, and thus it can measure a sensor signal which is mixed in the circuit noise in the conventional method. The foregoing discussion discloses and describes merely a number of exemplary embodiments of the present invention. As will be understood by those skilled in the art, the present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. Accordingly, the disclosure of the present invention is intended to be illustrative of, but not limiting to, the scope of the invention, which is set forth in the following claims. Thus, the present invention may be embodied in various ways within the scope of the spirit of the invention.
	abstract	Exemplary embodiments of an improved OBT are provided. General concepts of the invention include an OBT combined with an optical scanner. In one embodiment, the OBT includes a housing that at least partially retains a processor; vehicle communication circuitry for linking to a vehicle diagnostic system, and an optical reader for optically obtaining additional information. Another exemplary embodiment includes an OBT used in conjunction with a bar code scanner and/or a camera. In addition, a method of obtaining diagnostic data from the vehicle diagnostic system and optically obtaining information using an off-board device is provided.
043228534	summary	This invention relates to the control of nuclear reactors and, more particularly, to the control of heat cycles in large nuclear reactors. The invention applies specifically to horizontal-column, natural-uranium, graphite-moderated, water-cooled nuclear reactors. Reactors of this general type are disclosed in U.S. Pat. No. 2,910,418 issued Oct. 27, 1959 to E. C. Creutz et al. Natural-uranium, graphite-moderated nuclear reactors are inherently all very large in size. In such reactors localized phenomena may result in heat and flux cycles wherein a surge of heat and flux, or "hot spot", occurs at some location within the reactor and the action taken to cool off the "hot spot" results in a hot spot at some other location in the reactor. One particular form of reactor to which the invention particularly applies which is now in operation is a graphite-moderated, water-cooled reactor operated with natural uranium as fuel for the production of plutonium. In these reactors process tubes containing the fuel extend through horizontal channels in the graphite. Cooling water passes through these process tubes over the fuel. The horizontal channels are overbored at the front and rear of the reactor to increase the temperature of the graphite at these locations. The graphite temperature is raised near the edges of the reactor where it is normally relatively low to reduce graphite distortion due to accumulation of stored energy. Finally, control rods which extend horizontally into the reactor at right angles to the process tubes are concentrated near the center of the reactor to obtain the maximum effect therefrom. When a reactor is operating at constant power, insertion of a control rod because of a hot spot requires withdrawal of a control rod at some other location in the reactor to maintain the power level constant. Insertion of a control rod at the hot spot causes a reduction in graphite temperature at that point. Reduction of the graphite temperature has a reactivity effect of its own independent of the control rods. Changing the graphite temperature changes the cross-section of the graphite as well as changing the thermal neutron energy. Since the graphite cools gradually, reactivity gradually decreases after movement of the control rod is completed. It is thus necessary to move the control rod out again to compensate for this decrease in reactivity. At the same time a control rod is inserted near the hot spot, a control rod is withdrawn at another location in the reactor to maintain a constant power level. Because of the control rod withdrawal, heating occurs at this other location. The reactivity increases after a delay because of the increased graphite temperature and the control rod must be reinserted. In other words, the action taken to counter a hot spot causes a hot spot somewhere else in the reactor and the action taken to counter the second hot spot causes another hot spot at the first or another location. The heating and cooling occurring in these heat cycles is reinforced by the xenon effect. When power is reduced in a given area, xenon-135 increases slowly since it is not being destroyed by radiation capture as fast as it is being produced by decay. This results in a further reduction in reactivity and further cooling of the graphite. Several hours later, reactivity again begins to increase, reinforcing the reactivity increase obtained by the countermovement of the control rod. These hot spots are most noticeable near the fringe of the reactor where no control rods exist and the temperature has been artificially increased by overboring the graphite channels. A hot spot may, for example, move from the front to the rear of the reactor or the reverse, thus establishing what may be called front-to-rear heat cycles. As a result of this problem, it has been necessary at times to decrease the power level of operation of the reactor to avoid uncontrollable heat cycles. This, of course, results in decreased production of plutonium. It is accordingly an object of the present invention to develop means for controlling a nuclear reactor. It is a more detailed object of the present invention to develop means for controlling heat cycles in a nuclear reactor. It is a still more detailed object of the present invention to develop means for controlling front-to-rear heat and flux shifts in a nuclear reactor. It is incidentally an object of the present invention to develop novel means for limiting the movement of the aforesaid control means. These and other objects of the present invention are attained by incorporating a control column in one or more of the reactor process tubes and providing means for varying the horizontal displacement of the control column. The control column contains fewer fuel elements than are in a normal fuel column and control elements disposed at at least one end of the control column. According to the preferred embodiment control elements are disposed at both ends of the control column so the total length thereof is greater than that of a fuel column and the amount of fuel and poison are balanced so that movement of the control column varies the over-all reactivity balance of the reactor only slightly.
	description	The present invention relates to electron optical lens columns and to manufacturing methods thereof. Electron optical lens columns are used in order to produce lens effects on electron beams such as in scanning electron microscopes (SEMs) and ion beam (EB) equipment. An example of a lens column used in an SEM is described as an “electrostatic lens” in Japanese Unexamined Patent Application Publication H 6-187901. However, recently there have been demands for high precision and tighter focusing of electron beams for the purposes of, for example, microlithography processes. Increasing the degree of focus requires high acceleration of the electrons through applying a high voltage. However, this engenders problems in terms of bulky and expensive equipment. Furthermore, high velocity electrons engender the following problems: (a) Because the electron beam penetrates the surface of the sample, it is no longer suitable for observing the surface. (b) There will be deleterious effects, such as the sample being destroyed by the electron beam. (c) With biological samples, the material is nonconductive, and thus electrostatic charge tends to build up. Charged material has an impact on the electric field, adversely affecting the precision of the focus of the electron beam. However, if it were possible to obtain a compact, high-precision lens column, it would then be possible to shorten the distance between the electrode and the electron beam, making it possible to subject the electron beam to large electric fields even if the acceleration voltage on the electrons is low, and, in turn, making it possible to focus the beam with high precision. Unfortunately, the electrostatic lenses used in electron optical lens columns require high precision in their placement and dimensions. When lens columns have been made smaller, there has been a tendency for there to be increased error in the positioning and dimensions of the electrostatic lenses, which may lead to reductions in focusing precision. The present invention is the result of consideration of the factors described above. The object of the present invention is to provide an electron optical lens column, and a manufacturing method thereof, suitable to miniaturization. The electron optical lens column according to the present invention comprises electrostatic lenses arrayed on the inner surface of the column unit. The inner surface of said column unit has high-resistance electrical conductivity. The inner surface of said column unit, in said electron optical lens column, may be structured from a ceramic material that has high-resistance electrical conductivity. The aforementioned column unit may be structured from essentially a single material. Said single material may be a ceramic material that has high-resistance electrical conductivity. The aforementioned high-resistance electrical conductivity refers to a state where, for example, the resistivity is in the range of 108 to 1010 Ω-cm. Said column unit may comprise an inner column and an outer column. Said inner column may be disposed within said outer column. The electrostatic lens may be provided with, on the inner surface of said column unit, with electrodes for producing an electric field. Interconnections for applying voltages to said electrodes may be connected to said electrodes. Said interconnections may be provided between said inner column and said outer column. A plurality of said electrodes may be provided. Said interconnections may connect together those electrodes having identical electric potentials. Said interconnections may be structured so as to mutually connect, via resistances or switching elements, those said electrodes having differing electric potentials. Said electrostatic lenses may be equipped, on the inner surface of said column unit, with electrodes for generating electric fields. Said electrodes may be attached to the inner surface of said column unit. For electrodes equipped in multiple electrostatic lenses, multiple electrode parts, mutually separate from each other, may be provided. The number of electrode parts in each of said electrodes may be identical. Multiple electrostatic lenses may be provided with electrodes, said electrodes may be provided with multiple electrode parts that are mutually separate from each other, and those of said electrode parts that are of identical electrical potentials may be structured so as to be mutually connected electrically by interconnections. The electron optical lens column of the present invention may be structured so that said column unit comprises an inner column and an outer column, where said inner column is disposed within said outer column, multiple electrostatic lenses are each provided, on the inside of said column units, with electrodes for producing electric fields, said electrodes are equipped on the inner surface of said column unit, said electrodes are equipped with multiple electrode parts that are separate from each other, those of said electrode parts having identical electric potentials are mutually connected, electrically, via interconnections, and said interconnections are disposed between said inner column and said outer column. Conversely, the electron optical lens column of the present invention may be structured so that the aforementioned column unit has an inner column and an outer column, the aforementioned inner column is disposed inside of the aforementioned outer column and contains a plurality of the aforementioned electrostatic lenses, each of said electrostatic lenses is equipped with electrodes for generating electric fields inside of the aforementioned column unit, the aforementioned electrodes are disposed on the inner surface of the aforementioned column unit, the aforementioned electrodes are equipped with a plurality of electrode parts that are mutually separate from each other, the aforementioned electrode parts are connected to each other via interconnections and resistances in order to apply differing voltages to these electrode parts, and the aforementioned interconnections and resistances are disposed between the aforementioned inner column and the aforementioned outer column. Conversely, the electron optical lens column of the present invention may be structured so that the aforementioned column unit has an inner column and an outer column, the aforementioned inner column is disposed inside of the aforementioned outer column and contains a plurality of the aforementioned electrostatic lenses, each of said electrostatic lenses is equipped with electrodes for generating electric fields inside of the aforementioned column unit, the aforementioned electrodes are disposed on the inner surface of the aforementioned column unit, the aforementioned electrodes are equipped with a plurality of electrode parts that are mutually separate from each other, the aforementioned electrode parts are connected to each other via interconnections and switching elements in order to apply differing voltages to these electrode parts, and the aforementioned interconnections and switching elements are disposed between the aforementioned inner column and the aforementioned outer column. The aforementioned electron optical lens column may be structured so as to form a plurality of said electrostatic lenses and grooves are formed between the aforementioned electrostatic lenses. The aforementioned electron optical lens column may be structured so that the electrostatic lenses are equipped with a plurality of electrodes and grooves are formed between the aforementioned electrodes. The aforementioned electron optical lens column may be structured so that the aforementioned electrostatic lenses are equipped with a plurality of electrodes, said electrodes are each equipped with a plurality of electrode parts, and grooves are formed between said electrode parts. The aforementioned electron optical lens column may be structured so that an electron gun chamber is equipped at one end of the aforementioned column unit. The aforementioned electron optical lens column may be structured so that a secondary electron detector is equipped at the other end of said column. The aforementioned electron optical lens column may be equipped with a flange for attaching the electron gun chamber, integrated with the column unit, at one end of the column unit. The aforementioned electron optical lens column may be equipped with a column part, which forms a side wall of an electron gun chamber, on one end of the aforementioned column unit, and integrated with the aforementioned column unit. The scanning electron microscope of the present invention is equipped with a lens column as described above. The ion beam device of the present invention is equipped with a lens column as described above. The manufacturing method for the electron optical lens column of the present invention has the following steps: (1) A step that coats an electrically conductive material on the inner surface of a column unit, and (2) A step that obtains one set of electrodes for structuring an electrostatic lens through the removal of a portion of the aforementioned electrically conductive material that has been coated. Conversely, the manufacturing method for the electron optical lens column may have “a step that obtains one set of electrodes for forming the lens through coating an electrically conductive material in a specific pattern on the inner surface of the column unit.” Conversely, the manufacturing method for the electron optical lens column according to the present invention may have the following steps: (1) A step that coats an electrically conductive material on the inner surface of a column unit, (2) A step that obtains multiple electrodes for structuring one or more electrostatic lenses through the removal of a portion of the aforementioned electrically conductive material that has been coated, and (3) A step that connects, via interconnections, those aforementioned multiple electrodes that have identical electric potentials. Conversely, the manufacturing method for the electron optical lens column according to the present invention may have the following steps: (1) A step that coats an electrically conductive material on the inner surface of a column unit, (2) A step that obtains multiple electrode parts for structuring electrodes for electrostatic lenses through removing a portion of the aforementioned electrically conductive material that has been coated, and (3) A step that connects, via interconnections, those aforementioned multiple electrode parts that have identical electric potentials. Conversely, the manufacturing method for the electron optical lens column according to the present invention may have the following steps: (1) A step that arranges interconnections on the outer surface of a column unit, (2) A step that forms, in an inner column, either before or after the aforementioned step (1), through holes for connecting the aforementioned interconnections with electrodes that are disposed on the inner surface of said inner column, (3) A step that fits an outer column onto the outside of said inner column, (4) A step that forms, in said outer column, either before or after the aforementioned step (3), through holes for connecting the aforementioned interconnections with outside circuitry on the aforementioned outer column. An electron optical lens column according to a first example of the present invention will be explained below, based on FIGS. 1 through 12. The lens column according to this example embodiment is provided with a column unit 1, an electrostatic lens (sometimes abbreviated as simply “lens” in this description) 2, disposed on the inner surface of this column unit 1, an electron gun chamber 3, interconnections 4, and a secondary electron detector 5. (See FIGS. 1 through 7.) The column unit 1 is equipped with an inner column 11, and outer column 12, and a flange 13. (See FIG. 1.) A high-resistance electrically conductive ceramic is used as the material for all of these in this example embodiment. Furthermore, in this example embodiment, the resistivity of the high-resistance electrically conductive ceramic is in the range of 108 to 1010 Ω-cm. More preferably, the resistivity should be in the range of about 108 to 109 Ω-cm. Resistivities that are too high will prevent the electric charge from leaking, which will tend to cause charge buildup. Conversely, resistivities that are too low will cause there to be a large leakage current between electrodes. This resistivity, preferably, is set so as to produce electric charge leakage to a degree that can effectively prevent charge buildup. In the range described above, the resistivity is preferably set to a high value to prevent the leakage current. Ceramic compositions that can be used in the present example embodiment include, for example, a mixture of 10 to 20% of TiO2 in a base ingredient of Al2O3, or a mixture of about 30% Fe2O3 and 4% Y2O3 in a base ingredient of ZrO2. Conversely, a mixture of about 0.2% to 1% of B, Al2O3 and/or Y2O3 into SiC as the base material may also be used. The ceramic in the present example embodiment preferably has a relatively high resistivity (about 109 Ω-cm), and, preferably, has a density that is near to that of the pure material. From this perspective, either pure Al2O3 or a mixture of 15% of TiO2 into Al2O3, with characteristics near thereto, is preferred. Given the structure, the inner surface of the column unit 1 (or in other words, the inner surface 111 of the inner column 11) is structured from a high-resistance electrically conductive ceramic. Furthermore, given the structure described above, the column unit 1 is structured from, essentially, a single material (that is to say, the high-resistance electrically conductive ceramic). The inner column 11 and the outer column 12 can typically be obtained through, firing after molding ceramic powder at high-pressure. The inner column 11 is cylindrical. Through holes 113, which connect between the inner surface 111 and the outer surface 112, are formed in the inner column 11. (See FIG. 7.) Interconnections 114, which are connected to electrodes (described below) attached to the inner surface 111, and which extend to the outer surface 112, are disposed inside the through holes 113. The outer column 12 is a cylindrical shape that fits on the outside of the inner column 11. More specifically, the inner diameter of the outer column 12 is slightly smaller than the outer diameter of the inner column 11, so that the outer column 12 can be fitted onto the inner column 11 through a heated fitting process or through a chilled fitting process. As with the inner column 11, through holes connecting the inner surface 121 and the outer surface 122, are formed in the outer column 12. (See FIG. 7.) Interconnections 124, which are connected to the interconnections 114 of the inner column 11, or connected to interconnections 4, which are disposed on the outer surface of the inner column 11, which extends to the outer surface 122 of the outer column 12, is disposed on the inside of the through holes 123. An electrostatic lens 2 is equipped with a gun lens 21, an astigmatism corrector 22, an XY deflector 23, and an object lens 24. (See FIG. 1.) The lens effect of the lens 2 is shown schematically in FIG. 3. The gun lens 21 is of a triode type, equipped with electrodes 211, 212, and 213. (See FIG. 1.) When a single lens is structured from multiple electrodes, these multiple electrodes shall be referred to as “1 set of the electrodes.” Each of these electrodes 211 to 213 is shaped as a thin ring. The thickness of each of the electrodes 211 to 213 is, for example, 2 to 5 microns. The widths of each of the electrodes 211 to 213 can be, for example, between 3 and 6 mm. These widths are generally determined by the electron optics characteristics required in the lens, and determined in consideration of ease of manufacturing. Grooves 1111, which extend in the peripheral direction of the inner column 11, are formed between these electrodes 211 to 213. The electrodes 211 to 213 are separated from each other by these grooves 1111. The electrodes 211 and 213, on each side, are connected to zero volts (ground). Note that in the specification “connected to ground” is also termed “having a voltage applied.” The structure is such that an appropriate voltage (that is, a voltage that is capable of generating the required electric field) is applied to the center electrode 212. (The interconnections will be described below.) The astigmatism corrector 22 is provided with one electrode 221. The electrode 221 is equipped with eight electrode parts 2211 through 2218, arranged in the peripheral direction on the inner column 11. FIG. 4 shows the arrangement of electrode parts 2211 through 2218. Grooves 1112, extending in the axial direction of the inner column 11, are formed between the electrode parts 2211 through 2218. The electrode 221 is divided into the electrode parts 2211 through 2218 by the grooves 1112. The voltages described below are applied to the various electrode parts 2211 through 2218 via interconnections (described below). Note that “0 V” means that the applicable electrode is connected to the ground. Electrode parts 2211 and 2215: Vy (V), Electrode parts 2212, 2213, 2216 and 2217: 0 (V), and Electrode parts 2214 and 2218: Vx (V). Here the index letters “x” and “y” indicate two mutually orthogonal directions. The voltage Vy indicates the voltage V required for eliminating that part of the astigmatism that occurs in the y direction. The voltage Vx indicates the voltage V required for eliminating that part of the astigmatism that occurs in the x direction, perpendicular to the y direction. The multiple electrode parts that share identical electric potentials are connected to each other via interconnections 4, as explained below. The XY deflector 23 is equipped with 2 electrodes 231 and 232, which extend in the peripheral direction. (See FIG. 1.) The electrodes 231 and 232 are separated from each other by a groove 1111, extending in the peripheral direction, lying therebetween. These electrodes 231 and 232 are each equipped with eight electrode parts, 2311 through 2318 and 2321 through 2328, respectively. FIG. 2 and FIG. 5 show the layouts of these electrode parts. As with the astigmatism corrector 22, grooves 1112, extending in the axial direction, are formed between each of the electrode parts. The various voltages listed below are applied via interconnections (described below) to the respective electrode parts 2311 through 2318 and 2321 through 2328: Electrode parts 2311, 2312, 2321 and 2322: Vy (V), Electrode parts 2313, 2318, 2323 and 2328: b0 Vy (V), Electrode parts 2314, 2317, 2324, and 2327: −b0 Vy (V), and Electrode parts 2315, 2316, 2325, and 2326: −Vy (V). In the above, b0 equals 20.5−1. The multiple electrode parts that share identical electric potentials are connected to each other via interconnections 4, as described below, here as well. As with the gun lens 21, the object lens 24 is also a triode-type, equipped with electrodes 241, 242, and 243. (See FIG. 1.) The various electrodes 241 to 243 are shaped as thin rings. The electrodes 241 and 243, on both sides, are connected to 0 V (ground). The structure is such that an appropriate voltage (that is, the voltage that is able to produce the required electric field) is applied to the center electrode 212. (The interconnections will be described below.) The other structure in the object lens 24 is the same as in the gun lens 21. The electron gun chamber 3 is equipped with a vacuum chamber 31, an ion pump 32, and an electron gun cathode 33. (See FIG. 6.) The vacuum chamber 31 is attached to a flange 13 of the column unit 1. The electron gun cathode 33 is disposed in a position that is coaxial with the column unit 1. The base part of the electron gun cathode 33 is attached to the inner surface of the vacuum chamber 31. The tip part of the electron gun cathode 33 is disposed facing the column unit 1. The ion pump 32 is equipped with a yoke 321, permanent magnets 322, a cathode 323, and an anode 324. The yoke 321 has a cylindrical body 3211, and two flanges 3212, integrated with said body 3211, on either side thereof. The permanent magnets 322 are equipped on the opposite surfaces of the two flange parts 3212. The cathode 323 is disposed on the side surface (outer peripheral surface) of the body 3211. The anode 324 is the inner surface of the vacuum chamber 31, and is disposed facing the cathode 323. The cathode 323 and the anode 324 can be formed through, for example, plating or vapor deposition. The interconnections 4 are disposed between the inner column 11 and the outer column 12. In the present example embodiment, the interconnections 4 connect the interconnections 114 of the inner column 11, which are connected to those electrodes or electrode parts that share identical electric potentials, with the interconnections 124 of the outer column 12. (See FIG. 7.) The interconnections 4 include interconnections 41, which extend in the axial direction of the column unit 1, and interconnections 42, which extend in the peripheral direction of the column unit 1. (See FIG. 9.) The interconnections 41, as shown in FIG. 7, are disposed in the two locations described below. For reference, FIG. 8 shows a cross-sectional diagram along the line C—C of FIG. 7. (1) The positions that connect together the interconnections 114, which are connected to the electrodes 211 and 213 that comprise the gun lens 21, and (2) The positions that connect together the interconnections 114, which are connected to the electrodes 241 and 243 that comprise the object lens 24. The interconnections 42 that extend in the peripheral direction of the column unit 1 are disposed in the following locations: (1) As shown in FIG. 9 and FIG. 10, the positions wherein the electrode parts 2311 through 2318 in the electrode 231 of the XY deflector 23 that share identical electric potentials are connected to each other, (2) As with the aforementioned (1), the positions wherein the electrode parts 2321 through 2328 of the electrode 232 that share identical electric potentials are connected to each other (not shown), and (3) As with the aforementioned (1) and (2), the positions wherein the electrode parts 2211 through 2218 of the astigmatism corrector 22 that share identical electric potentials are connected to each other. The secondary electron detector 5 is attached to the end of the column unit 1. (See FIG. 1 and FIG. 7.) The structure of the secondary electron detector 5 is the same as that which is conventionally known, so detailed explanations will be omitted. The method of manufacturing the lens column in the present example embodiment will be explained next, based on FIG. 11 and FIG. 12. First, an appropriate method, such as firing, is used to obtain the inner column 11 and the outer column 12. After this, preferably, the inner surface 111 of the inner column 11 is polished to increase the dimensional precision. After this, the through holes 113, which penetrate in the inward-outward direction, are formed on the side surfaces of the inner column 11. After this, the insides of the through holes 113 are filled with electrically conductive materials, such as solder. This produces the interconnections 114 in the inner column 11. Following this, the interconnections 4 are formed on the outer surface 112 of the inner column 11. (FIG. 11 A) The interconnections 4 can be formed using any appropriate method, such as plating or vapor deposition. Following this, the outer column 12 is fitted onto the outside of the inner column 11, using a heated fitting process or a chilled fitting process. (FIG. 11 B) Following this, through holes 123, which pass through the outer column 12 in the inward-outward direction, are formed in the side surface of the outer column 12. (FIG. 11 C) Following this, as with a case for the through holes 113, the through holes 123 are filled with an electrically conductive material. (FIG. 11 D) This makes it possible to obtain the interconnections 124 in the outer column 12. The locations of the various aforementioned through holes and interconnections are determined in advance. Following this, the flange 13 is attached to the ends of the inner column 11 and the outer column 12, thus producing the column unit 1. (FIG. 12 A and FIG. 12 B) Note that FIG. 12 omits the descriptions of the interconnections and through holes shown in FIG. 11. Following this, a means, such as plating or vapor deposition, is used to form a metal coating V on the inner surface of the inner column 11. (FIGS. 12 C and D) After the metal coating V has been formed, a polishing process is performed in order to increase the surface precision. Following this, the grooves 1111 and 1112, which partition the respective lenses and electrodes, are formed. (FIGS. 12 E and F) The method of fabricating these grooves 1111 and 1112 may use, for example, etching in photolithography. Of course, the grooves may instead be formed using mechanical machining. The fabrication of the grooves in this way partitions the metal coating V to produce the electrodes or electrode parts. The operation of the lens column of the present invention will be explained next. First the operation of the electron gun chamber 3 will be explained. (See FIG. 6.) In the electron gun chamber 3, a high voltage is applied in the cathode 323 and the anode 324. The electrons that are extracted from the cathode in this way are caused, by the effects of the magnetic field generated by the permanent magnets 322, to move in a helical path, and said electrons collide with residual gas molecules. When this occurs, the residual gas molecules are ionized, and are adsorbed onto the cathode 323. Because this ion pump effect is well known, all further explanation will be omitted. The effect makes it possible to achieve a high vacuum within the ion pump 32. Following this, the effect of the gun lens 21 extracts electrons from the electron gun cathode 33. The extracted electrons pass through the astigmatism corrector 22, the XY deflector 23, and the object lens 24, to arrive at the object. (See FIG. 3.) Because, in the lens column according to the present example embodiment, the column unit 1, and in particular, the inner column 11, has a high-resistance electrical conductivity, it is possible to reduce the amount of charge buildup between the electrodes (where said charge buildup is the amount of charge that occurs through the scattered electrons accumulating on the surface of insulators that are exposed between the electrodes). If the resistivity on the inner surface of the column unit 1 is too high, then charge buildup will occur between the electrodes, causing a problem in that the charge buildup will disrupt the electric field within the column unit 1. Disruptions in the electrode field will reduce the degree of focus of the electrons, which will result, for example, in the blurring of the SEM image. This problem can be avoided easily in the lens column according to the present example embodiment. Furthermore, because the inner column 11 is structured from a single material in the lens column according to the present example embodiment, and because the electrodes are formed on the surface of the inner column 11, it becomes possible to position the electrodes easily and with high precision. Because the interconnections 4 are provided between the inner column 11 and the outer column 12 in the lens column according to the present invention, it is possible to reduce the size of the lens column, when compared to a case where the interconnections are provided on the outside of the lens unit 1. Because the electrodes that have identical electric potentials are connected in the lens column according to the present invention, it is possible to reduce the number of connection points on the outside of the lens column 1. For example, in the gun lens 21, the electrode 211 and the electrode 213, which have identical electric potentials, have shared interconnections. If each of the electrodes were connected with outside interconnections independently, then there would be a total of three connections. In contrast, this can be reduced to two connections in the present example embodiment. Similarly, the provision of the interconnections 4 makes it possible to reduce the number of connections with outside interconnections in the astigmatism corrector 22, the XY deflector 23, and the object lens 24. This makes it possible to simplify the operations for attaching the lens column to a scanning electron microscope or to an electron beam device. A lens column according to a second example embodiment of the present invention will be explained next, based on FIG. 13. In this example embodiment, a vacuum chamber 31 of the electron gun chamber 3 has a column part 311 and a cover part 312. The column part 311 has a structure that is integrated with the flange 13 of the column unit 1. The electron gun cathode 33 and yoke 321 attach to the inner surface of the cover part 312. The anode 324 is attached to the inner surface of the column part 311. The balance of the structure is identical to that which has already been described for the first example embodiment, and is assigned the same numbering, and so further explanations are omitted. Because the column part 311 that structures the vacuum chamber 31 is integrated with the column unit 1 in the lens column in the second example embodiment, it is possible to have excellent precision in the positioning of the electron gun chamber 3 and of the column unit 1. A lens column according to a third example embodiment of the present invention will be explained next. In this example embodiment, all of the electrodes are divided into eight parts by the axial direction grooves 1112, the same way as in the examples of FIG. 4 and FIG. 5. In this case, as with the gun lens 21 and the object lens 24, each of the electrode parts in the rotationally symmetric electrodes is mutually connected via the interconnections 4. Because the grooves 1112 are formed for all of the electrodes in the third example embodiment, it is possible to form the grooves 1112 along the inner surface of the inner column 11 all at once, with the benefit of being able to simplify the manufacturing operations. Other structures and benefits are the same as for the first example embodiment, described above, and thus detailed explanations are omitted. A lens column according to a fourth example embodiment of the present invention will be explained next, based on FIG. 14. Note that FIG. 14 is for explaining the interconnections only, and so is presented schematically. In this lens column, resistances 43 are inserted in series in the interconnections 4, making it possible to apply different voltages to the various electrodes or electrode parts while still sharing the interconnections 4. Additionally, transistors or other switching elements can be used instead of the resistances 43. In such a case, it is possible to make complicated settings for the voltages applied. Note that the aforementioned descriptions of example embodiments are no more than mere examples, and do not indicate structures required in the present invention. The structures of the various parts are not limited to the above, insofar as they can fulfill the intent of the invention. For example, in the various example embodiments described above, the lens columns 1, as a whole, are structured from high-resistance electrically conductive ceramics. However, conversely, a structure may be used where only the inner surfaces of the lens columns 1 are structured from this composition. Furthermore, it is possible to have only the regions of the electrodes or the electrode parts be made from this composition. In addition, when the electrodes or electrode parts are formed, they can be applied with the specific pattern from the start, using, for example, a printing method. Moreover, in these example embodiments, the lens columns used two-layer structures; however, the present invention is not limited thereto, but, for example, multilayer structures of three or more layers may be used instead. In addition, in these example embodiments, the inner column 11 and outer column 12 were fitted together through a heated fitting process or a chilled fitting process after firing the ceramics. However, said columns may be fitted together prior to firing, after high-pressure molding of the ceramic instead, with both columns fired together in this state. The inner column and outer column may be fitted together through this method instead. The present invention makes it possible to provide an electron objects lens column suitable for miniaturization, and to provide a manufacture method thereof.
050531905	abstract	A water cooled nuclear reactor comprises a reactor core, a primary water coolant circuit and a pressurizer arranged as an integral unit in a pressure vessel. The pressure vessel is divided into an upper chamber and a lower chamber by a casing, the reactor core and primary coolant circuit are arranged in the lower chamber and the pressuriser is arranged in the upper chamber.. A plurality of pipes interconnect a steam space of the pressuriser with an upper portion of the primary coolant circuit via ports in the casing. A plurality of re-entrant surge ports interconnect a water space of the pressuriser with a lower portion of the primary coolant circuit. The surge ports have low flow resistance for water from the water space to the primary coolant circuit and high flow resistance in the opposite direction.
046997598	claims	1. In a reconstitutable fuel assembly including at least one guide thimble with an upper end portion having a central axis and a top nozzle with an adapter plate having top and bottom spaced apart surfaces and at least one passageway extending between said surfaces, a double lock joint structure for attaching said top nozzle adapter plate in releasable locking engagement upon said guide thimble upper end portion, comprising: (a) means defined in said upper end portion of said guide thimble to permit inward elastic collapse thereof to a compressed position upon application of forces directed radially inward toward the axis of said upper end portion and outward elastic return thereof to an expanded position upon removal of said radially inward directed forces; (b) upper means formed in said upper end portion of said guide thimble so as to provide said upper end portion at the location of said upper means with a diametric size greater than that of said adapter plate passageway when said guide thimble upper end portion is at its expanded position and a diametric size less than that of said adapter plate passageway when said upper end portion is collapsed to its compressed position upon application of said radially inward directed forces during insertion and withdrawal of said upper end portion into and from said adapter plate passageway; and (c) lower means formed in said upper end portion of said guide thimble so as to provide said upper end portion at the location of said lower means with a diametric size greater than that of said adapter plate passageway when said guide timble upper end portion is at either one of its expanded and collapsed positions; (d) said upper means being axially displaced from said lower means through a distance approximately equal to that between said top and bottom surfaces of said adapter plate such that with said upper end portion of said guide thimble inserted through said adapter plate passageway, said upper means is located above said adapter plate adjacent to said top surface thereof, said lower means is located below said adapter plate adjacent to said bottom surface thereof and said adapter plate is placed in a captured position between said upper and lower means of said guide thimble upper end portion. (e) a locking tube insertable into and removable from said upper end portion of said guide thimble between a locking position which maintains said upper end portion in said expanded position and said adapter plate in said captured position between said upper and lower means and an unlocking position which permits said upper end portion to inwardly collapse to said compressed position upon insertion and removal of said adapter plate onto and from said upper end portion. (a) means in the form of at least one axially extending slot defined in said upper end portion of said guide thimble to permit inward elastic collapse thereof to a compressed position upon application of forces directed radially inward toward the axis of said upper end portion and outward elastic return thereof to an expanded position upon removal of said radially inward directed forces; (b) upper means in the form of a bulge formed in said upper end portion of said guide thimble so as to provide said upper end portion at the location of said upper bulge with an outside diametric size greater than the inside diametric size of said adapter plate passageway when said guide thimble upper end portion is at its expanded position and less than the inside diametric size of said adapter plate passageway when said upper end portion is collapsed to its compressed position upon application of said radially inward directed forces during insertion and withdrawal of said upper end portion into and from said adapter plate passageway; and (c) lower means in the form of a bulge formed in said upper end portion of said guide thimble so as to provide said upper end portion at the location of said lower bulge with an outside diametric size greater than the inside diametric size of said adapter plate passageway when said guide timble upper end portion is at either one of its expanded and collapsed positions; (d) said upper bulge being axially displaced from said lower bulge through a distance approximately equal to that between said top and bottom surfaces of said adapter plate such that with said upper end portion of said guide timble inserted through said adapter plate passageway, said upper bulge is located above said adapter plate adjacent to said top surface thereof, said lower bulge is located below said adapter plate adjacent to said bottom surface thereof and said adapter plate is placed in a captured position between said upper and lower bulges of said guide thimble upper end portion. (e) a locking tube insertable into and removable from said upper end portion of said guide thimble between a locking position which maintains said upper end portion in said expanded position and said adapter plate in said captured position between said upper and lower bulges of said guide thimble upper end portion and an unlocking position which permits said upper end portion to inwardly collapse to said compressed position upon insertion and removal of said adapter plate onto and from said upper end portion. (a) means in the form of at least one axially extending slot defined in said upper end portion of said guide thimble to permit inward elastic collapse thereof to a compressed position upon application of forces directed radially inward toward the axis of said upper end portion and outward elastic return thereof to an expanded position upon removal of said radially inward directed forces; (b) upper means in the form of an annular bulge formed in said upper end portion of said guide thimble and having an outside diametric size greater than the inside diametric size of said adapter plate passageway when said guide thimble upper end portion is at its expanded position and less than the inside diametric size of said adapter plate passageway when said upper end portion is collapsed to its compressed position upon application of said radially inward directed forces during insertion and withdrawal of said upper end portion into and from said adapter plate passageway; (c) lower means in the form of an annular bulge formed in said upper end portion of said guide thimble and having an outside diametric size greater than the inside diametric size of said adapter plate passageway when said guide thimble upper end portion is at either one of its expanded and collapsed positions; (d) said upper annular bulge being axially displaced from said lower annular bulge through a distance approximately equal to that between said top and bottom surfaces of said adapter plate such that with said upper end portion of said guide thimble inserted through said adapter plate passageway, said upper annular bulge is located above said adapter plate adjacent to and in contact with said top surface thereof, said lower annular bulge is located below said adapter plate adjacent to and in contact with said bottom surface thereof and said adapter plate is placed in a captured position between said upper and lower annular bulges of said guide thimble upper end portion; and (e) a locking tube insertable into and removable from said upper end portion of said guide thimble between a locking position which maintains said upper end portion in said expanded position and said adapter plate in said captured position between said upper and lower annular bulges of said guide thimble upper end portion and an unlocking position which permits said upper end portion to inwardly collapse to said compressed position upon insertion and removal of said adapter plate onto and from said upper end portion; (f) said locking tube including upper and lower axially displaced protuberances adapted to mate with said upper and lower annular bulges of said guide thimble upper end portion when said locking tube is inserted at its locking position therein. 2. The double lock joint structure as recited in claim 1, further comprising: 3. The double lock joint structure as recited in claim 2, wherein said locking tube includes upper and lower axially displaced means adapted to mate with said upper and lower means of said guide thimble upper end portion when said locking tube is inserted at its locking position therein and unmate from said upper and lower means when said locking tube is removed from said guide thimble upper end portion. 4. The double lock joint structure as recited in claim 3, wherein said upper and lower axially displaced means are circumferentially displaced protuberances formed in said locking tube. 5. The double lock joint structure as recited in claim 4, wherein said locking tube includes a top annular flange located above said upper protuberance for facilitating insertion and removal of said tube into and from said guide thimble upper end portion. 6. The double lock joint structure as recited in claim 1, wherein said means defined in said upper end portion of said guide thimble to permit inward collapse thereof to said compressed position is at least one axially extending slot formed in said upper end portion. 7. The double lock joint structure as recited in claim 1, wherein said upper means is an annular bulge formed in said upper end portion of said guide thimble. 8. The double lock joint structure as recited in claim 1, wherein said lower means is an annular bulge formed in said upper end portion of said guide thimble. 9. In a reconstitutable fuel assembly including at least one guide thimble with an upper end portion having a central axis and a top nozzle with an adapter plate having top and bottom spaced apart surfaces and at least one passageway extending between said surfaces, a double lock joint structure for attaching said top nozzle adapter plate in releasable locking engagement upon said guide thimble upper end portion, comprising: 10. The double lock joint structure as recited in claim 9, further comprising: 11. In a reconstitutable fuel assembly including at least one guide thimble with an upper end portion having a central axis and a top nozzle with an adapter plate having top and bottom spaced apart surfaces and at least one passageway extending between said surfaces, a double lock joint structure for attaching said top nozzle adapter plate in releasable locking engagement upon said guide thimble upper end portion, comprising: 12. The double lock joint structure as recited in claim 11, wherein said locking tube includes a top annular flange located above said upper protuberance for facilitating insertion and removal of said tube into and from said guide thimble upper end portion.
048287903	claims	1. A process for inhibiting deposition of radioactive substances on nuclear power plant components which comprises forming a positively charged oxide film on surface of components contacting with nuclear reactor cooling water containing radioactive substances by treating the surface of components with a solution containing anions and polyvalent metal cations, the anions having a lower valence number than the cations at a time of forming an oxide film or after the formation of the oxide film, wherein the polyvalent metal cations are at least one member selected from the group consisting of Al.sup.3+, Fe.sup.3+, Ba.sup.2+, Ca.sup.2+, Co.sup.2+, Mg.sup.2+, Ni.sup.2+, Pb.sup.2+, Zn.sup.2+ and Cu.sup.2+, and the anions are at least one member selected from the group consisting of HCO.sub.3.sup.-, H.sub.2 PO.sub.4.sup.-, MnO.sub.4.sup.-, NO.sub.2.sup.-, NO.sub.3.sup.-, OH.sup.-, HCOO.sup.-, CH.sub.3 COO.sup.-, MnO.sub.4.sup.2-, HPO.sub.4.sup.2-, SO.sub.4.sup.2- and WO.sub.4.sup.2-. 2. A process according to claim 1, wherein the solution containing the polyvalent metal cations and the anions has a temperature of 150.degree. to 300.degree. C. 3. A process according to claim 1, wherein the polyvalent metal cations are used in a concentration of 3 ppb to 1000 ppm. 4. A process according to claim 1, wherein said polyvalent metal cations are selected from the group consisting of Al.sup.3+, Fe.sup.3+, Ba.sup.2+, Ca.sup.2+, Co.sup.2+, Mg.sup.2+, Ni.sup.2+, Pb.sup.2+, Zn.sup.2+ and Cu.sup.2+, and wherein the anions are selected from the group consisting of HCO.sub.3.sup.-, H.sub.2 PO.sub.4.sup.-, MnO.sub.4.sup.-, NO.sub.2.sup.-, NO.sub.3.sup.-, OH.sup.-, HCOO.sup.- and CH.sub.3 COO.sup.-. 5. A process according to claim 1, wherein said polyvalent metal cations are selected from the group consisting of Al.sup.3+ and Fe.sup.3+, and wherein the anions are selected from the group consisting of MoO.sub.4.sup.2-, HPO.sub.4.sup.2-, SO.sub.4.sup.2- and WO.sub.4.sup.2-. 6. A process according to claim 3, wherein the positively charged iron oxide film is formed to have a thickness of at least 300 .ANG.. 7. A process according to claim 1, wherein the components are formed of materials selected from the group consisting of stainless steel; carbon steel; cobalt-chromium-tungsten alloy; and nickel-chromium-iron alloy. 8. A process according to claim 7, wherein the components are formed of carbon steel. 9. A process according to claim 7, wherein the components are formed of materials selected from the group consisting of cobalt-chromium-tungsten alloy and nickel-chromium-iron alloy. 10. A process according to claim 1, wherein said treating is performed by pouring said solution into said cooling water, whereby solution-containing cooling water treats the surfaces of the components. 11. A process according to claim 10, wherein said surfaces of components are made of stainless steel. 12. A process for inhibiting deposition of radioactive substances on nuclear power plant components which comprises forming a positively charged iron oxide film containing metallic elements giving polyvalent metal cations and chromium on surfaces of components contacting with nuclear reactor cooling water containing radioactive substances, the positively charged iron oxide film being formed by contacting said surfaces of components with a solution containing said polyvalent metal cations and anions having a lower valence number than the cations, wherein the polyvalent metal cations are at least one member selected from the group consisting of Al.sup.3+, Fe.sup.3+, Ba.sup.2+, Ca.sup.2+, Co.sup.2+, Mg.sup.2+, Ni.sup.2+, Pb.sup.2+, Zn.sup.2+ and Cu.sup.2+, and the anions are at least one member selected from the group consisting of HCO.sub.3.sup.-, H.sub.2 PO.sub.4.sup.-, MnO.sub.4.sup.-, NO.sub.2.sup.-, NO.sub.3.sup.-, OH.sup.-, HCOO.sup.-, CH.sub.3 COO.sup.-, MnO.sub.4.sup.2-, HPO.sub.4.sup.2- , SO.sub.4.sup.2- and WO.sub.4.sup.2-. 13. A process according to claim 12, wherein the chromium content in the iron oxide film is 12% by weight or more. 14. A process according to claim 12, wherein the polyvalent metal cations are used in a concentration of 3 ppb to 1000 ppm. 15. A process according to claim 14, wherein the components are made of stainless steel. 16. A process according to claim 15, wherein the solution has a temperature of 150.degree. to 300.degree. C. 17. A process for inhibiting deposition of radioactive substances on nuclear power plant components made of an iron series material and contacting with reactor cooling water containing radioactive substances, which comprises treating surfaces of components made of a chromium-containing iron series material with heated water or heated steam to form an oxide film containing chromium in an amount of 12% by weight or more. formed thereon, prior to operation of the plant to provide nuclear heating, the oxide film having a chromium content of at least 12% by weight, wherein said oxide film is a positively charged oxide film, formed by contacting said surfaces with a solution containing polyvalent metal cations and anions having a lower valence number than the cations. 18. A process according to claim 17, further comprising the step of treating said surfaces of components with a solution containing polyvalent metal cations and anions having a lower valence number than the cations so as to form a positively charged iron oxide film on said surfaces of components, whereby said surfaces have a positively charged iron oxide film and an oxide film containing chromium in an amount of 12% by weight or more. 19. A process according to claim 18, wherein the polyvalent metal cations are at least one member selected from the group consisting of Al.sup.3+, Fe.sup.3+, Ba.sup.2+, Ca.sup.2+, Mg.sup.2+, Ni.sup.2+, Pb.sup.2+, Zn.sup.2+ and Cu.sup.2+, and the anions are at least one member selected from the group consisting of HCO.sub.3.sup.-, H.sub.2 PO.sub.4.sup.-, MnO.sub.4.sup.-, NO.sub.2.sup.-, NO.sub.3.sup.-, OH.sup.-, HCOO.sup.-, CH.sub.3 COO.sup.-, MnO.sub.4.sup.2-, HPo.sub.4.sup.2-, SO.sub.4.sup.2- and WO.sub.4.sup.2-. 20. A process according to claim 19, wherein the polyvalent metal cations are used in a concentration of 3 ppb to 1000 ppm. 21. A process according to claim 20, wherein the heated water or the heated steam contains a reducing agent. 22. A process according to claim 17, wherein the heated water has a temperature of 150.degree. to 300.degree. C. 23. A process according to claim 17, wherein the heated steam has a temperature of 150.degree. to 1000.degree. C. 24. A process according to claim 17, wherein said surfaces are a coating of chromium or chromium-containing iron series material, said coating being a chromium plated film, chromizing treated film or chromium vapor deposited film. 25. A process according to claim 17, wherein the components are formed of materials selected from the group consisting of stainless steel; carbon steel; and cobalt-chromium-tungsten alloy; and nickel-chromium-iron alloy. 26. A process according to claim 25, wherein the components are formed of carbon steel. 27. A process according to claim 25, wherein the components are formed of materials selected from the group consisting of cobalt-chromium-tungsten alloy and nickel-chromium-iron alloy. 28. A process according to claim 21, wherein the reducing agent is also a chelating agent. 29. A process according to claim 21, wherein the reducing agent is a Ni salt of ethylenediamine-tetraacetic acid or a nickel salt of nitrilotriacetic acid. 30. In a nuclear power plant comprising a reactor, a turbine, a condenser, a condensed water demineralizer, a supplying water heater, a demineralizer for a reactor cleaning system, and a reactor re-circulation piping system, the improvement wherein a positively charged iron oxide film is formed on surfaces which contact with nuclear reactor cooling water in said plant, the positively charged iron oxide film being formed by contacting said surfaces with a solution containing polyvalent metal cations and anions having a lower valence number than the cations. 31. A nuclear power plant according to claim 30, wherein the polyvalent metal cations are at least one member selected from the group consisting of Al.sup.3+, Fe.sup.3+, Ba.sup.2+, Co.sup.2+, Mg.sup.2+, Ni.sup.2+, Pb.sup.2+, Zn.sup.2+ and Cu.sup.2+, and the anions are at least one member selected from the group consisting of HCO.sub.3.sup.-, H.sub.2 PO.sub.4.sup.-, MnO.sub.4.sup.-, NO.sub.2.sup.-, NO.sub.3.sup.-, OH.sup.-, HCOO.sup.-, CH.sub.3 COO.sup.-, MnO.sub.4.sup.2-, HPO.sub.4.sup.2-, SO.sub.4.sup.2- and WO.sub.4.sup.2-. 32. In a nuclear power plant comprising a reactor, a turbine, a condenser, a condensed water demineralizer, a supplying water heater, a demineralizer for a reactor cleaning system, and a reactor re-circulation piping system, the improvement wherein a positively charged iron oxide film is formed on surfaces which contact with nuclear reactor cooling water in said plant, the positively charged iron oxide film being formed by contacting said surfaces with a solution containing polyvalent metal cations and anions having a lower valence number than the cations, after the construction of said plant and prior to the operation thereof to provide nuclear heating. 33. A nuclear power plant according to claim 32, wherein the polyvalent metal cations are at least one member selected from the group consisting of Al.sup.3+, Fe.sup.3+, Ba.sup.2+, Ca.sup.2+, Co.sup.2+, Mg.sup.2+, Ni.sup.2+, Pb.sup.2+, Zn.sup.2+ and Cu.sup.2+, and the anions are at least one member selected from the group consisting of HCO.sub.3.sup.-, H.sub.2 PO.sub.4.sup.-, MnO.sub.4.sup.-, NO.sub.2.sup.-, NO.sub.3.sup.-, OH.sup.-, HCOO.sup.-, CH.sub.3 COO.sup.-, MnO.sub.4.sup.2-, HPO.sub.4.sup.2-, SO.sub.4.sup.2- and WO.sub.4.sup.2-. 34. In a nuclear power plant comprising a reactor, a turbine, a condenser, a condensed water demineralizer, a supplying water heater, a demineralizer for a reactor cleaning system, and a reactor re-circulation piping system, the improvement wherein a positively charged iron oxide film is formed on surfaces which contact with nuclear reactor cooling water contaminated with radioactive substances after the operation of said plant, the positively charged iron oxide film being formed by contacting said surfaces with a solution containing polyvalent metal cations and anions having a lower valence number than the cations. 35. A nuclear power plant according to claim 34, wherein the polyvalent metal cations are at least one member selected from the group consisting of Al.sup.3+, Fe.sup.3+, Ba.sup.2+, Ca.sup.2+, Co.sup.2+, Mg.sup.2+, Ni.sup.2+, Pb.sup.2+, Zn.sup.2+ and Cu.sup.2+, and the anions are at least one member selected from the group consisting of HCO.sub.3.sup.-, H.sub.2 PO.sub.4.sup.-, MnO.sub.4.sup.-, NO.sub.2.sup.-, NO.sub.3.sup.-, OH.sup.-, HCOO.sup.-, CH.sub.3 COO.sup.-, MnO.sub.4.sup.2-, HPO.sub.4.sup.2-, SO.sub.4.sup.2- and WO.sub.4.sup.2-. 36. In a nuclear power plant comprising a reactor, a turbine, a condenser, a condensed water demineralizer, a supplying water heater, a demineralizer for a reactor cleaning system, and a reactor re-circulation piping system, the improvement wherein surfaces of the plant which contact with nuclear reactor cooling water have an oxide film formed thereon, prior to operation of the plant to provide nuclear heating, the oxide film having a chromium content of at least 12% by weight, wherein said oxide film is a positively charged oxide film, formed by contacting said surfaces with a solution containing polyvalent metal cations and anions having a lower valence number than the cations.
	claims	1. An apparatus for transferring spent nuclear fuel, the apparatus comprising:a cylindrical inner shell forming a cavity configured to receive a canister containing spent nuclear fuel, the cavity configured so that an annulus is formed between a canister placed in the cavity and an inner wall of the cylindrical inner shell;an intermediate shell disposed concentrically around and spaced apart from the inner shell;an outer shell disposed concentrically around and spaced apart from the intermediate shell;a bottom flange affixed to bottoms of each of the shells;a bottom lid removably affixed to the bottom flange and including at least one first channel fluidically connecting the annulus to an exterior of the bottom lid, wherein the at least one first channel is configured to preclude a direct line of travel from within the cavity to the exterior of the bottom lid, and wherein the at least one first channel comprises a toroidal-shaped distribution channel;a top flange affixed to tops of each of the shells and including at least one second channel fluidically connecting the first annulus to an exterior of the top flange, wherein the at least one second channel is configured to preclude a direct line of travel from within the cavity to the exterior of the top flange; anda top lid removably affixed to the top flange. 2. The apparatus of claim 1, wherein the toroidal-shaped distribution channel includes a plurality of distribution outlets fluidically connecting to the annulus and at least one distribution inlet fluidically connecting to the exterior of the bottom lid. 3. The apparatus of claim 2, further comprising a compressed air tank having an air outlet fluidically coupled to the distribution inlet. 4. The apparatus of claim 3, further comprising a cooling system configured to cool air within the compressed air tank. 5. The apparatus of claim 1, wherein the at least one first channel comprises a plurality of channel inlets distributed approximately equidistantly around the bottom lid. 6. The apparatus of claim 1, wherein an axial length of each of the shells is approximately the same. 7. The apparatus of claim 1, wherein a neutron absorber is disposed in a space formed between the intermediate shell and the outer shell. 8. The apparatus of claim 1, wherein a lead annulus is disposed in a space formed between the intermediate shell and the inner shell. 9. The apparatus of claim 1, the top flange comprising at least two integrally formed trunnions configured to enable hoisting of the apparatus, each trunnion disposed within a recess of the top flange. 10. The apparatus of claim 1, wherein the bottom lid further comprises an impact zone comprising an impact absorbing structure. 11. The apparatus of claim 10, wherein the impact absorbing structure comprises a plurality of tubes distributed throughout the impact zone, the tubes having longitudinal axes aligned with a major dimension of the bottom lid. 12. The apparatus of claim 10, wherein the bottom lid further comprises an impact zone comprising an impact absorbing structure. 13. The apparatus of claim 10, wherein the impact zone extends substantially under an entirety of the cavity. 14. An apparatus for transferring spent nuclear fuel, the apparatus comprising:a cylindrical inner shell forming a cavity configured to receive a canister containing spent nuclear fuel, the cavity configured so that an annulus is formed between a canister placed in the cavity and an inner wall of the cylindrical inner shell;an intermediate shell disposed concentrically around and spaced apart from the inner shell;an outer shell disposed concentrically around and spaced apart from the intermediate shell;a bottom flange affixed to bottoms of each of the shells;a bottom lid removably affixed to the bottom flange and including at least one first channel fluidically connecting the annulus to an exterior of the bottom lid, wherein the at least one first channel is configured to preclude a direct line of travel from within the cavity to the exterior of the bottom lid, and wherein the at least one first channel comprises a toroidal-shaped distribution channel;a top flange affixed to tops of each of the shells, the top flange including at least two integrally formed trunnions configured to enable hoisting of the apparatus, each trunnion disposed within a recess of the top flange; andthe top flange including and including at least one second channel fluidically connecting the first annulus to an exterior of the top flange, wherein the at least one second channel is configured to preclude a direct line of travel from within the cavity to the exterior of the top flange; anda top lid removably affixed to the top flange. 15. The apparatus of claim 14, wherein the trunnions are distributed approximately equidistantly around the top flange. 16. The apparatus of claim 14, wherein top flange has a smaller outer diameter as compared to the outer shell. 17. An apparatus for transferring spent nuclear fuel, the apparatus comprising:a cylindrical inner shell forming a cavity configured to receive a canister containing spent nuclear fuel, the cavity configured so that an annulus is formed between a canister placed in the cavity and an inner wall of the cylindrical inner shell;an intermediate shell disposed concentrically around and spaced apart from the inner shell;an outer shell disposed concentrically around and spaced apart from the intermediate shell;a bottom flange affixed to bottoms of each of the shells;a bottom lid removably affixed to the bottom flange, the bottom lid including an impact zone comprising an impact absorbing structure, wherein the impact zone extends substantially under an entirety of the cavity;the bottom lid including at least one first channel fluidically connecting the annulus to an exterior of the bottom lid, wherein the at least one first channel is configured to preclude a direct line of travel from within the cavity to the exterior of the bottom lid, and wherein the at least one first channel comprises a toroidal-shaped distribution channel;a top flange affixed to tops of each of the shells and including at least one second channel fluidically connecting the first annulus to an exterior of the top flange, wherein the at least one second channel is configured to preclude a direct line of travel from within the cavity to the exterior of the top flange; anda top lid removably affixed to the top flange. 18. The apparatus of claim 17, wherein the impact absorbing structure comprises a plurality of tubes distributed throughout the impact zone, the tubes having longitudinal axes aligned with a major dimension of the bottom lid. 19. The apparatus of claim 18, wherein each of the plurality of tubes is a cylindrical tube. 20. The apparatus of claim 17, wherein the bottom lid further comprises a neutron absorber, and the impact zone is disposed between the neutron absorber and the cavity.
047568674	summary	FIELD OF THE INVENTION The invention relates to a device for the remote measurement of the outside diameter of a cylindrical element projecting relative to the surface of a plate perforated with at least two orifices in the vicinity of the cylindrical element. BACKGROUND OF THE INVENTION In pressurized-water nuclear reactors, the lower core plate supporting the fuel assemblies has, in line with each of the assemblies, water passage orifices passing through it over its entire thickness and an instrumentation guide bush projecting relative to the face of the lower core plate, on which the assemblies come to rest. This guide bush is arranged in such a way that its axis coincides with the axis of the instrumentation tube of the corresponding assembly. The instrumentation guide tube is located in the central part of the assembly and receives the glove finger, within which a teleflex cable carrying a neutron-flux sensor at its end is moved along, in order to carry out flux measurements over the entire height of the assembly while the reactor is in operation. Such measurements can thus be made over the entire height of the core in the region of each of the assemblies The guide bush projecting relative to the lower core plate forms the end of a guide duct, in which the glove finger can be moved along in either direction to introduce it into the fuel assembly or, conversely, to extract it, for example at the time when the core is being reloaded. Each guide bush is located, relative to the corresponding assembly, inside the lower end piece, via which the assembly rests on the lower core plate. The guide bush is completely free inside the lower end piece of the assembly, its axis being aligned with that of the assembly solely as a result of the relative positioning of the bush and the assembly on the lower core plate. In pressurized-water nuclear reactors operating at the present time, the guide bushes of the glove fingers, which are fastened to the lower core plate, consequently do not have an accurately defined outside diameter, since this dimension is not critical to ensure that the guide duct is aligned with the guide tube of the assembly. To make it easier to install the fuel assemblies and allow differential expansion, the upper end of the guide bush is located at a relatively long distance from the entrance of the guide tube of the assembly, within the lower end piece. Consequently, the glove finger, when introduced into the assembly, is exposed, in the free space existing between the guide bush and the end piece, to cross-currents of cooling water which can make it vibrate. To overcome this disadvantage, it has been proposed, for example, to provide a matching guide unit which caps the guide bush and which bears on the part of the end piece into which the guide tube of the assembly opens. The fitting of such a matching guide and protective device presents certain difficulties which arise because the guide bushes in the nuclear reactors operating at the present time do not have a perfectly defined and absolutely constant outside diameter. On the other hand, it is difficult to carry out accurate measurements on highly irradiated equipment which has to be placed under a head of water exceeding ten meters during reactor shutdown and maintenance phases. Finally, the large number of guide bushes arranged on a lower core plate of a nuclear reactor, corresponding to a number of fuel assemblies in excess of one hundred, makes it necessary to use a measuring process and device which can be installed and put into operation quickly and reliably at a distance. A device making it possible to carry out such remote measurements of outside diameters repetitively has not been known to date. However, there are various known devices which are used for conducting tests or dimensional checks on nuclear reactor elements, these devices comprising a pole of great length which can be manipulated from a location above the reactor pool; however, such devices have never been designed to carry out accurate diameter measurements. SUMMARY OF THE INVENTION The object of the invention is, therefore, to provide a device for the remote measurement of the outside diameter of a cylindrical element projecting relative to the surface of a plate perforated with at least two orifices in the vicinity of the cylindrical element, and such a device comprises a handling pole of great length and a measuring apparatus connected to the end of the pole and is intended to make it possible to carry out repetitive measurements quickly and very accurately, particularly on elements such as guide bushes fastened to the upper face of the lower core plate of a pressurized-water nuclear reactor. To achieve this object, the measuring apparatus comprises: (a) a supporting structure consisting of a plane annular base provided with at least two projecting guide and centering parts intended to interact with the orifices in the plate and a thrust assembly consisting of an arm mounted in an articulated manner on the base and having a bearing means at its end, and of a finger actuating the arm and mounted so as to project relative to a face of the base intended to come into contact with the plate, in order to actuate the thrust arm when they come into contact, and (b) a measuring assembly carried by the supporting structure and consisting of a stage mounted on the annular base so as to be movable in all directions of the plane of the base and with limited amounts of movement, of a tubular sleeve which is integral with the stage and the axis of which is perpendicular to the plane of the stage and of the base and the inside diameter of which is greater than the diameter to be measured, and of a tracer which is associated with a movement measuring means and which is carried by the tubular sleeve and has a rod which is movable in a radial direction of the tubular sleeve and the end of which projects into the bore of the tubular sleeve under the action of a spring, (c) the arm of the thrust assembly exerting a radially-directed thrust on the outer surface of the tubular sleeve in a zone diametrically opposite the tracer, when the device is placed in the active measuring position, the tubular sleeve surrounding the cylindrical element to be measured and the plane annular base of the supporting structure coming to rest on the plate.
	description	This application is a divisional of U.S. application Ser. No. 12/569,123,filed Sep. 29, 2009 which is based upon and claims the benefits of priority from the prior Japanese Patent Application No. 2008-253187, filed on Sep. 30, 2008, the entire content of which is incorporated herein by reference. The present invention relates to a power monitoring system (or a power range monitor) of a boiling water reactor and particularly to a power monitoring system that monitors the power oscillations of a nuclear reactor core. In the boiling water reactor (BWR), the output power alternately falls and rises due to the generation and disappearance of voids, respectively, which may possibly generate power oscillations whereby the output power of the nuclear reactor oscillates and is amplified. The widely known reactor core power oscillation monitoring method is to continue operation as long as the soundness of core fuel is secure even in an operating range in which power oscillations occur, and to detect, when oscillations occur that could lead to events affecting the soundness of the core fuel, the oscillations, and safely stop the operation of the nuclear reactor (See, for example, U.S. Pat. No. 5,174,946,the entire content of which being incorporated herein by reference). Also widely known is a reactivity adjustment method that stabilizes the entire reactor core using the above-described method (See, for example, U.S. Pat. No. 5,141,710,the entire content of which being incorporated herein by reference). High reliability is required to monitor the power oscillations of the reactor core in terms of securing the soundness of the core fuel. However, the problem with the above-described monitoring of power oscillations is that even though oscillations that could lead to events affecting the soundness of the core fuel can be detected when the oscillations occur, necessary measures may not have been taken to secure the soundness of the fuel. The present invention has been made to solve the above-described problems. The objective of the present invention is to provide a power monitoring system that can monitor the power oscillations of the reactor core and establish high reliability in securing the soundness of the core fuel. In order to achieve the objective, a power monitoring system according to an aspect of the present invention comprises: a local power range monitoring device that has a plurality of local power channels to obtain local neutron distribution in a nuclear reactor core; an averaged power range monitoring device that receives power output signals from the local power range monitoring device and obtains average output power signal of the reactor core as a whole; and an oscillation power range monitoring device including an oscillation power range monitoring mechanism that receives the power output signals from the local power range monitoring device and monitors power oscillations of the reactor core, wherein output signals from the local power range monitoring device to the averaged power range monitoring device and output signals from the local power range monitoring device to the oscillation power range monitoring device are independent. A power monitoring system according to another aspect of the present invention comprises: a local power range monitoring device that has a plurality of local power channels to obtain local neutron distribution in a nuclear reactor core; an averaged power range monitoring device that receives power output signals from the local power range monitoring device and obtains average output power of the reactor core as a whole; and an oscillation power range monitoring device including an oscillation power range monitoring mechanism that receives the power output signals from the local power range monitoring device and monitors power oscillations of the reactor core, wherein the averaged power range monitoring device transmits output signals from the local power range monitoring device to the oscillation power range monitoring device with the output not passing through an averaged power range monitor processing function in the averaged power range monitoring device. A power monitoring system according to yet another aspect of the present invention comprises: a local power range monitoring device that has a plurality of local power channels to obtain local neutron distribution in a nuclear reactor core; and an averaged power range monitoring device that receives power output signals from the local power range monitoring device and obtains average output power of the reactor core as a whole, wherein the averaged power range monitoring device includes an averaged power range monitor processing mechanism and an oscillation power range monitoring mechanism, and an input from the local power range monitoring device to the averaged power range monitor processing mechanism is independent of an input from the local power range monitoring device to the oscillation power range monitoring mechanism. Hereinafter, embodiments of a power monitoring system (a power range monitor) of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a block diagram illustrating the configuration of a power range monitor according to a first embodiment of the present invention. As shown in the diagram, a power range monitor (PRM) 13 has: local power range monitor (LPRM) units 1a and 1b, which are a plurality of local power range monitoring devices that obtain the local neutron distribution signals in a nuclear reactor core; an averaged power range monitor (APRM) unit 2, which is an averaged power range monitoring device that receives the power output signals from the LPRM units 1a and 1b and obtains the average output power of the entire reactor core; and an oscillation power range monitor (OPRM) unit 3, which is an oscillation power range monitoring device that receives the power output signals from the LPRM units 1a and 1b and monitors the power oscillations of the reactor core. The inputting of local power signals to the OPRM unit 3 and the inputting of local power signals to the APRM unit 2 are performed by the LPRM units 1a and 1b, respectively, and are shared. Incidentally, a process of monitoring the power oscillations of the reactor core inside the OPRM unit 3 is referred to as an OPRM process, and a process of securing the soundness of the core fuel in the APRM unit 2 is referred to as an APRM process. The transmitting of signals from the LPRM units 1a and 1b to the OPRM unit 3 is limited to one-way transmission from the LPRM units 1a and 1b to the OPRM unit 3 via output modules 4a and 5a of the LPRM units 1a and 1b. The transmitting of signals from the LPRM units 1a and 1b to the APRM unit 2 is limited to one-way transmission from the LPRM units 1a and 1b to the APRM unit 2 via the output modules 4b and 5b of the LPRM units 1a and 1b. The PRM 13 has a function to transmit channel signals of the LPRM units 1a and 1b as well as the breakdown or exclusion signals of each channel from the LPRM units 1a and 1b to the OPRM unit 3. When a breakdown or exclusion signal of any LPRM channel of the LPRM units 1a and 1b is generated, the corresponding LPRM channel is excluded in the arithmetic operation in the OPRM unit 3. Moreover, when a breakdown and/or exclusion signal of the LPRM units 1a or 1b themselves is generated, all the LPRM channels as a whole corresponding to the LPRM unit 1a or 1b are excluded by the OPRM process. According to the present embodiment, the outputting of signals from the LPRM units 1a and 1b to the OPRM unit 3 and the outputting of signals to the APRM unit 2 are limited to a one-way direction and carried out via the different output modules 4a and 5a and output modules 4b and 5b. Therefore, the functional independence of the OPRM unit 3 and the APRM unit 2 is sufficiently secured. Thus, the power oscillations of the reactor core can be monitored; high reliability can be established in terms of securing the soundness of the core fuel. FIG. 2 is a block diagram illustrating the configuration of a power range monitor according to a second embodiment of the present invention. The portions that are the same as or similar to those of FIG. 1 have been denoted by the same reference numerals to avoid repeating the same description. As shown in the diagram, a power range monitor (PRM) 13a has: LPRM units 1a and 1b, which are the local power range monitoring devices that obtain the local neutron distribution in a nuclear reactor core; an APRM unit 2, which receives the power output signals from the LPRM units 1a and 1b, and obtains the average output power of the entire reactor core; and an OPRM unit 3, which receives from the APRM unit 2 the power output signals from the LPRM units 1a and 1b and monitors the power oscillations of the reactor core. The inputting of local power signals to the OPRM unit 3 and the inputting of local power signals to the APRM unit 2 are performed by the LPRM units 1a and 1b, respectively, and are shared. The OPRM unit 3 and the APRM unit 2 have separate reactor-core monitoring functions, and the function of the OPRM unit 3 is formed independently of the function of the APRM unit 2. The APRM unit 2 includes: an LPRM signal receiving section 6, which receives LPRM signals; an LPRM signal transmitting section 7, which transmits the LPRM signals to the OPRM unit 3; and an APRM processing section 8, which orders the APRM unit 2 to perform a necessary process. In the APRM unit 2, once the LPRM signal receiving section 6 receives the LPRM signals from the LPRM units 1a and 1b, the received signals are transmitted to the LPRM signal transmitting section 7 and the APRM processing section 8. In the OPRM unit 3, the LPRM signals are received through the LPRM signal transmitting section 7 of the APRM unit 2. Incidentally, the PRM 13a has a function to transmit the breakdown or exclusion signals of any of LPRM channels and of the LPRM units 1a or 1b from the LPRM units 1a and 1b to the APRM unit 2. Moreover, the signals are designed to be transmitted to the OPRM unit 3. When a breakdown or exclusion signal of any LPRM channels and of the LPRM units 1a and 1b is generated, the corresponding LPRM channel is excluded by an arithmetic operation in the OPRM unit 3. Moreover, when a breakdown or exclusion signal of the LPRM unit 1a or 1b is generated, all the LPRM channels corresponding to the LPRM unit 1a or 1b are excluded by the OPRM process. According to the present embodiment, in the OPRM unit 3, the LPRM signals are received via the APRM unit 2. However, the LPRM signals do not pass through the APRM processing section 8 that performs an APRM process when the LPRM signals are transmitted. Therefore, the independence of the OPRM process and APRM process is sufficiently secured. Thus, the power oscillations of the reactor core can be monitored, and high reliability can be established in terms of securing the soundness of the core fuel. FIG. 3 is a block diagram illustrating the configuration of a power range monitor according to a third embodiment of the present invention. The portions that are the same as or similar to those of FIG. 1 have been denoted by the same reference numerals to avoid repeating the same description. As shown in the diagram, a power range monitor (PRM) 13b has: LPRM units 1a and 1b, which are the local power range monitoring devices that obtain the local neutron distribution in a nuclear reactor core; and an APRM unit 2, which receives the power output from the LPRM units 1a and 1b, and obtains the average output power of the entire reactor core. The APRM unit 2 includes: an LPRM signal receiving section 6, which receives LPRM signals; an APRM processing section 8, which orders the APRM to perform a necessary process; and an OPRM processing section 9, which orders an OPRM process. The OPRM processing section 9 and the APRM processing section 8 have separate reactor-core monitoring functions, and the function of the OPRM processing section 9 is formed independently of the function of the APRM processing section 8. The APRM unit 2 receives signals from the LPRM unit 1a and 1b. The inputting of local power signals to the OPRM processing section 9 and the inputting of local power signals to the APRM processing section 8 are performed by the LPRM units 1a and 1b, and they are shared. Once the APRM unit 2 receives the LPRM signals from the LPRM units 1a and 1b by using the LPRM signal receiving section 6, the APRM unit 2 separately transmits the received signals to the APRM processing section 8 and the OPRM processing section 9. The PRM 13b has a function to transmit the breakdown or exclusion signals of any LPRM channels and of the LPRM units 1a and 1b themselves from the LPRM units 1a and 1b to the APRM unit 2. When a breakdown or exclusion signal of an LPRM channel of the LPRM units 1a or 1b is generated, the corresponding LPRM channel is excluded by an arithmetic operation in the OPRM processing section 9. Moreover, when a breakdown or exclusion signal of the LPRM unit 1a or 1b is generated, all the LPRM channels corresponding to the LPRM units 1a or 1b are excluded by the OPRM processing section 9. According to the present embodiment, the OPRM processing section 9 is separated from the APRM processing section 8. Therefore, the independence of the OPRM process and APRM process is sufficiently secured. Thus, the power oscillations of the reactor core can be monitored, and high reliability can be established in terms of securing the soundness of the core fuel. The following describes an example of an OPRM unit of a power range monitor according to a fourth embodiment of the present invention, with reference to FIG. 1. In the OPRM unit 3, for example, the following parameters and the like are used as initial setting for monitoring oscillations: (1) Primary determination amplitude value (peak); (2) Secondary determination amplitude value (trough); (3) Multiplication factor determination value; (4) Trip determination amplitude value; (5) Oscillation interval minimum determination value; and (6) Oscillation interval maximum determination value. The above values need to be changed according to type of the core fuel and the like. Meanwhile, in terms of securing the soundness of the core fuel, measures to prevent the values from being easily changed are necessary. Accordingly, in the OPRM unit 3, the variables are set by hardware switches on a board that constitutes part of the OPRM unit 3. That is, in the OPRM unit 3, the variables, which are changed according to type of the core fuel of the nuclear reactor, are formed by a combination of electrical contacts that are so positioned as not to be operated without stopping the oscillation power range monitoring mechanism. According to the present embodiment, the setting values necessary for the process of monitoring the power oscillations of the reactor core are set by the hardware switches on the board. Therefore, it is difficult to change the setting values during normal operation unless the board is removed, preventing the variables, which are changed according to type of the fuel of the reactor core and the like, from being easily changed. Thus, the power oscillations of the reactor core can be monitored; high reliability can be established in terms of securing the soundness of the core fuel. The following describes an example of an OPRM unit of a power range monitor according to a fifth embodiment of the present invention, with reference to FIG. 1. In the OPRM unit 3, parameters, like those described in the fourth embodiment of the present invention, are used as initial setting for performing the process of monitoring the power oscillations of the reactor core. The variables need to be changed according to type of the core fuel and the like. Meanwhile, in terms of securing the soundness of the core fuel, measures to prevent the variables from being easily changed are necessary. Therefore, in the OPRM unit 3, the variables are set in EEP-ROM mounted on the board that constitutes part of the OPRM unit 3. Moreover, the OPRM unit 3 does not include a circuit that rewrites the EEP-ROM on the board. That is, the oscillation power range monitoring mechanism is so designed that the variables, which are changed according to type of the core fuel of the nuclear reactor, cannot be changed without stopping the oscillation power range monitoring mechanism, and are stored in an element whose internal state cannot be changed by the operation of the oscillation power range monitoring mechanism. The EEP-ROM (Electronically Erasable and Programmable Read Only Memory) is a kind of nonvolatile memory and is a semiconductor storage device that can erase or rewrite data by controlling electricity (voltage). Data can be erased from EEP-ROM by applying a higher-than-usual level of voltage. Accordingly, the mechanism of EEP-ROM can be relatively easily realized with no special device. Therefore, the EEP-ROM is used as a programmable element. According to the present embodiment, the setting values necessary for performing the process of monitoring the power oscillations of the reactor core are set through the EEP-ROM on the board, and there is no circuit that rewrites the EEP-ROM on the board. Therefore, it is difficult to change the setting values during normal operation unless the board is removed, preventing the variables, which are changed according to type of the core fuel and the like, from being easily changed. Thus, the power oscillations of the reactor core can be monitored, and high reliability can be established in terms of securing the soundness of the core fuel. FIG. 4 is a block diagram illustrating the configuration of a power range monitor according to a sixth embodiment of the present invention. The portions that are the same as or similar to those of FIG. 1 have been denoted by the same reference numerals to avoid repeating the same description. In the OPRM unit 3, the past history needs to be kept for a predetermined period of time. The history function does not directly affect the task of securing the soundness of the core fuel. Therefore, a transmission section 10 is provided in the OPRM unit 3 of a power range monitor 13c and is connected to a history recording device 12. The transmission section 10 has a one-way transmission function to transmit only the output signals not having input signals. Moreover, regarding a display mechanism (not shown) for monitoring the power oscillations of the reactor core, reliability is similarly required. Therefore, the one-way transmission of only the output signals not having input signals is carried out from the OPRM processing section. The output to the history recording device 12 is transmitted via an optical coupler 11. Therefore, the history recording device 12 is electrically isolated. Therefore, even if incompatibility and the like occur in the history recording device 12 and/or the display mechanism, the effect is not transmitted to the OPRM unit 3. Incidentally, the output signals may be transmitted in a serial or parallel way in the form of digital data. Alternatively, the output signals may be transformed into analog data by converting the signal level into voltage or current values, and then numerical conversion may be performed by the history recording device 12. In the case of digital transmission, the history recording device 12 may have not only the function to transmit output signals in a one-way direction but a function to confirm if data is normally transmitted by performing parity check to avoid the lack of data. Moreover, the transmission section 10 may have a function to retransmit data in accordance with the normal/abnormal determination result of data transmission from the history recording device 12 that performs parity check and the like. Incidentally, some measures, including the following ones, need to be taken: checking if the retransmitting function does not affect the process of securing the soundness of the core fuel of the nuclear reactor that the OPRM unit 3 performs; or while data is buffered in the transmission section 10, a measure, such as one that directs other processes of the OPRM unit 3 to the transmission section 10 to one direction, is taken not to affect the previous processes. The parity check is one of the methods to detect errors in data in data communication. In computers, all data are represented by sequences of binary numbers, i.e. 0 and 1. The parity check is a method to detect errors in data using binary numbers. Moreover, a determination means (not shown) may be provided to make a determination as to whether the data is normally received, and a determination result transmission means (not shown) may be provided to transmit the determination result of the determination means to the transmission section 10. Furthermore, the transmission of data from another oscillation power range monitoring mechanism (not shown) to the transmission section 10 is limited to the one-way transmission of output signals. According to the present embodiment, while the recording function of the past history is kept, the OPRM process performed ensures the necessary reliability for securing the soundness of the core fuel. Moreover, the transmission of data from the processing section related to the monitoring of power oscillations of the reactor core to the display mechanism is limited to the one-way transmission by which only the output signals not having input signals are transmitted. Therefore, similar reliability is maintained for the process of monitoring the power oscillations of the reactor core. The above has described the embodiments of the present invention. The present invention is, however, not limited to the above embodiments. Various modifications may occur by combining the structures of the above embodiments insofar as they are within the scope of the present invention.
	summary
053295641	abstract	A passive cooling system for removing decay heat from an open cycle nuclear reactor. Coolant tanks are filled with coolant during normal operation of the reactor and coolant pump. A check valve in the inlet line for each tank prevents loss of coolant through the inlet line. After the reactor is shut down and the coolant pump is inoperative, coolant flows from the coolant tanks through exhaust lines into the normal coolant line and to the reactor for removal of decay heat. A flow control valve or fixed orifice in the exhaust line for each tank provides for a different predetermined flow rate of coolant from each tank to match the decay heat rate of the reactor.
	abstract	The invention relates to an apparatus for X-ray imaging, in which imaging an X-ray beam (11) is directed through the object being imaged. The X-ray imaging apparatus (1) comprises an X-ray source (5) in front of the object being imaged, a primary collimator (6) in conjunction with the X-ray source, and radiation receiving means (15), which are located in a position behind the object being imaged. The apparatus relating to the invention comprises identifying means (20-22) which react to X-ray radiation, by means of which is ensured the entry of radiation inside the imaging area of the radiation receiving means (15).
	abstract	The shipping container includes an outer container body, an inner containment vessel housing a pair of superposed product pails and a self-extinguishing fire-retardant foam insulation layer between the outer container and inner vessel. The inner vessel includes a gusseted upper flange and a lid bolted to the flange with a sealing gasket therebetween. Upper and lower dunnages are provided at the upper and lower ends of the outer container. The upper dunnage includes ceramic fiberboard panels and foam material straddled by steel sheets and additional ceramic fiberboard panel to separate the lid of the vessel and the top of the container. The top is secured to the outer container body by bolts passing through the top and internally into tapped bolt brackets along an interior wall of the outer container body. A retaining ring secures the arcuate overlying rolled edge of the top about the beaded rim of the outer container body. A reinforced plate covers the seam of the outer container underneath the retaining ring bolt for additional container integrity. Vent holes with plastic plugs which melt in response to a predetermined temperature vent the container body to preclude pressure buildup within the container body by expanding gases.
	claims	1. A radioisotope production apparatus which irradiates a target material with a charged particle beam to produce a radioactive isotope, the apparatus comprising:a particle accelerator which emits the charged particle beam along a predetermined beam axis;a first target portion on which the charged particle beam emitted from the particle accelerator is incident and through which the charged particle beam passes; anda second target portion on which the charged particle beam having passed through the first target portion is incident,wherein the first target portion includes:a body barrel portion,a beam passage which is formed through the body barrel portion and through which the charged particle beam passes,a target holder which is attachable to and detachable from the body barrel portion,a target material holding portion which is formed in the target holder and is configured to hold a first target material on the beam axis in the beam passage, anda cooling gas supply unit which supplies a cooling gas for cooling the first target material;wherein the second target portion includes:a body portion,a substrate holding portion which is formed in the body portion and is configured to hold a target substrate, the target substrate includes a substrate body and a second target material provided on the substrate body, on the beam axis, anda cooling water supply unit which supplies cooling water for cooling the target substrate to a downstream-side surface of the target substrate with respect to the charged particle beam; andwherein a total thickness of the first target material and the target material holding portion of the first target portion on the beam axis is smaller than a thickness of the target substrate on the beam axis. 2. The radioisotope production apparatus according to claim 1,wherein the first target portion includes a plurality of the target material holding portions. 3. The radioisotope production apparatus according to claim 1,wherein the first target material is inserted onto and extracted from the beam axis in a direction intersecting the beam axis.
	abstract	The present invention is an electromagnetic controller assembly for use in ion implantation apparatus, and provides a structural construct and methodology which can be employed for three recognizably separate and distinct functions: (i) To adjust the trajectory of charged particles carried within any type of traveling ion beam which is targeted at a plane of implantation or a work surface for the placement of charged ions into a prepared workpiece (such as a silicon wafer or flat glass panel); (ii) concurrently, to alter and change the degree of parallelism of the ions in the traveling beam; and (iii) concurrently, to control the uniformity of the current density along the transverse direction of traveling ion beams, regardless of whether the beams are high-aspect, continuous ribbon ion beams or alternatively are scanned ribbon ion beams.
	abstract	A plurality of recording magnetization portions is arranged in a concentric manner around a center of a glass substrate. A plurality of non-magnetization portion having a thermal conductivity lower than that of the recording magnetization portions is formed each between adjacent recording magnetization portions along a circumferential direction on a main surface of the glass substrate. A mean squared roughness of a surface of an area where each of the non-magnetization portions is formed is equal to or smaller than 1 nanometer.
051732513	claims	1. In a gas-cooled, high-temperature nuclear reactor with a circular outline, a mixing apparatus for a plurality of turbulently flowing fluid flows varying in at least one of temperature and composition, comprising a horizontal, annular mixing chamber having a plurality of sectors, horizontal annular conduits for receiving at least one fluid flow, a plurality of vertical conduits being disposed above said sectors and having upper ends connected to said horizontal annular conduits and lower ends connected to said mixing chamber, an outlet opening communicating with said mixing chamber, said sectors having a plurality of bores formed therein in the vicinity of said outlet opening for receiving absorber material, and one of said sectors forming a plurality of deflector elements for deflecting the at least one fluid flow into said mixing chamber. 2. The mixing apparatus according to claim 1, including an at least partly star-shaped distributor distributing the fluid flows to a plurality of said radial deflector elements. 3. The mixing apparatus according to claim 1, wherein said deflector elements are widened in radial direction toward the outside. 4. The mixing apparatus according to claim 1, including a plurality of single-conduit and radial deflector elements disposed beside said mixing chamber. 5. The mixing apparatus according to claim 1, wherein said deflector elements have a curved wall in a cross-sectional plane of said mixing chamber. 6. The mixing apparatus according to claim 5, wherein said mixing chamber has a given full height, and said mixing chamber is joined over said given full height to said the deflector elements. 7. The mixing apparatus according to claim 5, wherein said mixing chamber is horizontally oriented and has a cover with outer vertical openings partly penetrating said cover above said mixing chamber. 8. The mixing apparatus according to claim 1, wherein the high-temperature nuclear reactor operates on the pebble bed principle, and said sectors form a central pebble discharge conduit. 9. The mixing apparatus according to claim 8, wherein said sectors have vertical bores formed therein in the vicinity of said pebble discharge conduit for receiving absorber material.
	summary
	claims	1. A method for determining a spatial and energy distribution of neutrons in a nuclear reactor lattice depletion, the method, when implemented by a computer, comprising the steps of:obtaining a reactor eigenvalue, the reactor eigenvalue being a specified ratio of actual neutron production to loss in a nuclear reactor;determining a lattice eigenvalue based upon reflective boundary conditions (α) of a lattice representing at least a portion of the nuclear reactor, the lattice eigenvalue being an estimated ratio of neutron production to loss in the lattice, the lattice including a lattice boundary comprising a plurality of boundary segments, the lattice boundary associated with the reflective boundary conditions along the plurality of boundary segments;adjusting at least one of the reflective boundary conditions (α) of the lattice to cause convergence of the lattice eigenvalue and the reactor eigenvalue, while maintaining the heterogeneity of the lattice;repeating the determining and adjusting steps, without homogenization of the lattice, until the lattice eigenvalue is within a preset limit of the reactor eigenvalue; andresponsive to the lattice eigenvalue being within the preset limit of the reactor eigenvalue, providing the adjusted reflective boundary conditions for determination of the spatial and spectral distribution of neutrons. 2. The method in claim 1, wherein the lattice eigenvalue is initially determined based upon user defined reflective boundary conditions. 3. The method in claim 2, wherein the user defined reflective boundary conditions vary along the plurality of boundary segments. 4. The method in claim 1, wherein the lattice eigenvalue is produced using a stochastic method. 5. The method in claim 4, wherein the stochastic method is a Monte Carlo method. 6. The method in claim 1, wherein the lattice eigenvalue is produced using a deterministic method. 7. The method in claim 1, wherein the at least one of the reflective boundary conditions is adjusted based upon a difference between the reactor eigenvalue and the lattice eigenvalue. 8. The method in claim 7, wherein adjustment of the at least one of the reflective boundary conditions varies along the plurality of boundary segments. 9. The method in claim 1, wherein the reflective boundary conditions are defined in terms of at least one reflection coefficient.
	abstract	Migration of radioactive materials from a pressure vessel to a steam system in a nuclear power plant is suppressed by using a dryer (3) provided with corrugated plates (22) having surfaces coated with an inorganic ion-exchange material stable under a condition in which high-temperature water exist, such as TiO2.
	abstract	A control device includes: an input portion for inputting a process signal transmitted from a plant; a numerical processing part for outputting a Boolean value evaluating normal/abnormal of the process signal by a numerical processing based on a program; and a logical processing part for a logical processing of the Boolean value based on a logic circuit and then outputting a control signal related a safety protection operation of the plant.
	claims	1. An electron beam irradiating apparatus for treating a layer formed on a wafer, said apparatus comprising: a chamber having an opening at a top side of the chamber; a cathode plate disposed to cover the opening of the chamber, at least the bottom surface of the cathode plate, which faces an inner bottom surface of the inside of the chamber, being formed of a non-metal conductive material; a susceptor on which the wafer can be loaded disposed on the inner bottom surface of the chamber; and a grid plate disposed between the cathode plate and the susceptor, wherein, upon application of a potential difference across the cathode plate and the grid plate, a beam of electrons released from the bottom surface of the cathode plate impinges on the layer formed on the wafer to treat the layer formed on the wafer. 2. The electron beam irradiating apparatus of claim 1 , wherein the cathode plate and the chamber are electrically insulated from each other. claim 1 3. The electron beam irradiating apparatus of claim 1 , wherein the grid plate is electrically insulated from the chamber and the cathode plate. claim 1 4. The electron beam irradiating apparatus of claim 1 , wherein the non-metal conductive material is silicon. claim 1 5. The electron beam irradiating apparatus of claim 1 , wherein the cathode plate comprises an upper cathode plate formed of a metal and a lower cathode plate formed of the non-metal conductive material. claim 1 6. The electron beam irradiating apparatus of claim 1 , wherein the cathode plate is a single cathode plate formed of the non-metal conductive material alone. claim 1 7. The electron beam irradiating apparatus of claim 1 , further comprising a vacuum pump coupled to the chamber for altering the pressure in the chamber. claim 1 8. The electron beam irradiating apparatus of claim 1 , further comprising a gas injection ring for allowing gas to enter the chamber. claim 1 9. The electron beam irradiating apparatus of claim 8 , wherein the gas injection ring is disposed between the grid plate and the susceptor. claim 8 10. The electron beam irradiating apparatus of claim 1 , wherein the layer is a spin-on-glass (SOG) layer. claim 1 11. The electron beam irradiating apparatus of claim 10 , wherein the beam of electrons is used to at least partially cure the SOG layer. claim 10 12. The electron beam irradiating apparatus of claim 1 , wherein the layer is a photoresist layer. claim 1
	abstract	A thermally conductive and electromagnetic interference and radio frequency reflective polymer composition and a method for creating the same is disclosed. Thermally conductive filler material is coated with a thermally conductive and electromagnetic interference and radio frequency reflective coating material and mixed with a base polymer matrix. The mixture is molded into the desired shape. The electromagnetic interference and radio frequency reflective coating material prevents the absorption and transfer of EMI and RF waves through the filler material thus resulting in an EMI and RF reflective composition.
	claims	1. An apparatus comprising:a pressure vessel comprising an upper vessel section and a lower vessel section;a nuclear reactor core comprising fissile material disposed the lower vessel section;a suspended support assembly that is suspended from the pressure vessel, including a plurality of hanger plates connected by tie rods, the plurality of hanger plates including a mid-hanger plate that is disposed between an upper hanger plate and a lower hanger plate; andupper internals disposed in the lower vessel section above the nuclear reactor core and mounted on the suspended support assembly, the upper internals including at least guide frames and internal control rod drive mechanisms (CRDMs) with CRDM motors;the internal CRDMs being disposed between the mid-hanger plate and the upper hanger plate, the guide frames being disposed below the mid-hanger plate, the mid-hanger plate engaging both the internal CRDMs and the guide frames. 2. The apparatus of claim 1, wherein the internal CRDMs are bottom supported by the mid-hanger plate. 3. The apparatus of claim 2, wherein the guide frames are top supported by the mid-hanger plate and hang below the mid-hanger plate. 4. The apparatus of claim 2, wherein the guide frames are bottom supported by the lower hanger plate that is disposed below the mid-hanger plate. 5. The apparatus of claim 4, wherein the mid-hanger plate provides lateral support for the guide frames. 6. The apparatus of claim 1, wherein the guide frames are top supported by the mid-hanger plate and hang below the mid-hanger plate. 7. The apparatus of claim 1, wherein the mid-hanger plate supports or includes a power distribution plate that distributes electrical power to the internal CRDMs. 8. The apparatus of claim 1, wherein the mid-hanger plate includes openings, each opening aligned with one internal CRDM and one guide frame. 9. The apparatus of claim 1, wherein:the upper hanger plate is disposed above the mid-hanger plate and engages the internal CRDMs but not the guide frames; andthe lower hanger plate is disposed below the mid-hanger plate and engages the guide frames but not the internal CRDMs. 10. The apparatus of claim 9, wherein the plurality of hanger plates consists of only said upper hanger plate, said mid-hanger plate, and said lower hanger plate. 11. An apparatus comprising:upper internals configured to be disposed as a unit in a pressure vessel of a nuclear reactor, the upper internals including:a suspended support assembly suspended from the pressure vessel, including a plurality of hanger plates connected by tie rods, the hanger plates including a mid-hanger plate, an upper hanger plate disposed above the mid-hanger plate, and a lower hanger plate disposed below the mid-hanger plate;guide frames mounted to the mid-hanger plate and the lower hanger plate; andinternal control rod drive mechanisms (CRDMs) with CRDM motors, the internal CRDMS mounted between the mid-hanger plate and the upper hanger plate. 12. The apparatus of claim 11, wherein the internal CRDMs are bottom supported by the mid-hanger plate and are laterally supported by the upper hanger plate. 13. The apparatus of claim 12, wherein the guide frames are top supported by the mid-hanger plate and hang below the mid-hanger plate, and are laterally supported by the lower hanger plate. 14. The apparatus of claim 12, wherein the guide frames are bottom supported by the lower hanger plate and the mid-hanger plate laterally supports the guide frames. 15. The apparatus of claim 11, wherein the guide frames are top supported by the mid-hanger plate and hang below the mid-hanger plate, and are laterally supported by the lower hanger plate. 16. The apparatus of claim 11, wherein the upper internals further include a distribution plate supported by the mid-hanger plate, the distribution plate configured to distribute electrical power to the internal CRDMs. 17. The apparatus of claim 11, wherein the mid-hanger plate includes openings, each opening aligned with one internal CRDM and one guide frame. 18. The apparatus of claim 11, further comprising a flange, the suspended support assembly of the upper internals being suspended from the flange.
054486122	summary	FIELD OF THE INVENTION AND RELATED ART This invention relates to an exposure apparatus and, more particularly, to an X-ray exposure apparatus using synchrotron radiation X-rays (SR X-rays) for transferring and printing a pattern of a mask onto a subsgrate such as a wafer. With increasing degree of integration of a semiconductor device, exposure apparatuses using synchrotron radiation X-rays (SR X-rays) have been developed which apparatuses are able to transfer and print a fine pattern, of a minimum linewidth 1/4 micron, for manufacture of a DRAM of 100 megabits or more. The practicalization of such exposure apparatus has been advanced largely by improvements in an exposure system of The type that the SR-X ray beam a sheet-beam shape emitted from an Synchrotron Orbital Radiation (SOR) ring is diverged by a convex mirror in a direction perpendicular to the orbit plane of the SOR ring. SUMMARY OF THE INVENTION In such SR-X ray exposure apparatus, uniform X-ray exposure amount has to be kept upon the surface of a substrate being exposed. However, there is a tendency that the strength of SR-X rays at the emission point on the SOR ring attenuates with time. This necessitates continuous monitoring of X-ray strength during the X-ray exposure operation as well as controlling the moving speed of an exposure controlling shutter device, adjacent to the substrate, in response to the change in the X-ray strength. Also, it is necessary to precisely control the relative position and the attitude (tilt and rotation) of the mirror relative to the sheet-beam like X-ray beam from the SOR ring. More particularly, where the direction of advancement of the sheet-beam like SR-X ray beam is taken in a z-axis direction, the thickness thereof is taken in a y-axis direction and the width thereof is taken in an x-axis direction, it is necessary to position, very precisely, the reflection surface of the mirror in the three axial directions (x, y and z) as well as rotational directions (wx, wy and wz) about the three axial directions, respectively. It is an object of the present invention to provide an improved exposure apparatus that assures more precise-pattern printing operation. It is another object of the present invention to provide a semiconductor device manufacturing method based on such an exposure apparatus as above. These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.
	summary
	abstract	The present invention relates to a multi-beamlet multi-column particle-optical system comprising a plurality of columns which are disposed in an array for simultaneously exposing a substrate, each column having an optical axis and comprising: a beamlet generating arrangement comprising at least one multi-aperture plate for generating a pattern of multiple beamlets of charged particles, and an electrostatic lens arrangement comprising at least one electrode element; the at least one electrode element having an aperture defined by an inner peripheral edge facing the optical axis, the aperture having a center and a predetermined shape in a plane orthogonal to the optical axis; wherein in at least one of the plurality of columns, the predetermined shape of the aperture is a non-circular shape with at least one of a protrusion and an indentation from an ideal circle about the center of the aperture.
045086419	summary	The invention concerns a process for the decontamination of steel surfaces, particularly in nuclear reactor coolant circuits, by the removal of the contaminated surface layer with an acid-containing aqueous decontaminating solution and for the preparation of the decontaminating solution containing the dissolved radioactive materials for waste disposal. To decontaminate nuclear reactor coolant circuits aqueous solutions of mineral acids are frequently used. Mineral acids are aggressive (corrosive) materials and it is therefore extremely difficult to control the course of the decontamination process by the sole means of adjusting the acid concentration, i.e., such that the contaminated surface layer is effectively removed within an acceptable time while the pure metal of the coolant circuit is not corroded. Corroded spots in the coolant system can lead to leaks which, because of the serious consequences, cannot be permitted. Consequently, complicated decontamination processes have been developed, one of the best known being the so-called "AP-CITROX" process ("Kernenergie" Volume 11, 1968, p. 285-290). In the first stage of this two-stage process the contaminated metallic surface is prepared in a treatment lasting several hours with an oxidising alkaline permanganate solution. In the second stage dissolution takes place with a reducing aqueous solution of a dibasic ammonium citrate, which also requires several hours. Each stage is followed by flushing with water. A similar two-stage decontamination process is described in U.S. Pat. No. 3,873,362. In the first process stage, aqueous solutions of alkali metal permanganates, nitric acid, sodium persulphate, sodium bromate an preferably hydrogen peroxide are used for oxidising the contaminated steel surface layer. For the reducing second process stage, aqueous solutions of mixtures of mineral acids, such as sulphuric acid and/or nitric acid and complex-forming materials, such as oxalic acid, citric acid or formic acid are provided, to which corrosion inhibitors, e.g., iron-(III)-sulphate, iron-(III)-nitrate, nitric acid, phenylthiourea or others may be added. The utilization of hydrogen peroxide in the first process stage has, by virtue of its ready decomposition into water and oxygen, the special advantage that the subsequent flushing with water can be dispensed with. Thereafter, the dissolved metallic components, together with the radioactive materials, are precipitated from the used decontaminating solution of the second process stage. For precipitation the sulphuric and oxalic acid contained in the decontaminating solution can be neutralized with calcium hydroxide so that calcium sulphate and calcium oxalate are formed which contain a great part of the radioactive materials present and which are then separated from the liquid by filtering. Alternatively, potassium permanganate may first by added to the used decontaminating solution in order to decompose the oxalic acid and to obtain manganese dioxide and manganese sulphate, which then can be precipitated by adjustment of the pH value to about 10 with, e.g., calcium hydroxide. Although here also the greater part of the radioactive material is removed with the precipitate, in both cases the filtrate is still contaminated and must be passed to nuclear waste disposal. Such two-stage decontamination processes may be performed as continuous processes or as batch processes. However, in addition to the long duration, the high consumption of chemicals and water are also unsatisfactory, and above all, in addition to the relatively high amount of solid radioactive waste, liquid radioactive waste is also obtained whereby the waste disposal of the used decontaminating solutions is a difficult problem. With the known processes the decontamination of nuclear reactor coolant circuits is laborious and relatively expensive, especially when corrosion of the pure metallic surfaces is excluded from consideration due to the safety requirements. Accordingly, the task of the present invention is to provide a decontamination process for nuclear reactor coolant circuits which requires lesser amounts of chemicals and flushing water for the decontamination of steel surfaces of the same area as the known two-stage processes, which permits a preparation of the used decontamination solution in which only minimum amounts of solid radioactive waste materials are present and wherein the liquid waste contains at most a low radioactivity, most likely lying below the permitted threshold value, which enables an easy control of the decontamination process and practically excludes the possibility of corrosion of the pure steel surfaces. The solution of the task according to the invention consists in the process defined in claim 1. SUMMARY OF THE INVENTION In the process according to the invention the decontamination solution contains formic acid and/or acetic acid and a reducing agent, preferably formaldehyde and/or acetaldehyde. These chemicals are not only very cheap but also relatively non-toxic, so that in the handling of this decontaminating solution no special safety measures are required. On contact with the steel surfaces to be decontaminated, Fe.sup.2+ ions go into solution. Accordingly, the decontamination process according to the invention is a single-stage process, which in contrast to a two-stage process assures a gain of time and cost. By means of the reducing agent contained in the decontaminating solution the Fe.sup.2+ ions are held stably in the solution. The liquid is of pale green colour, but is clear and transparent, without cloudiness, and its composition may be relatively easily monitored during the treatment of the steel surface. It has been shown that by such a decontaminating solution ion oxide is removed 10-15 times faster than the pure basic material and this permits the decontamination process to be conducted without great difficulties and in such a manner that an attack on the pure steel surface, which would lead to damaging corrosion by the decontaminating liquid, is practically impossible. For waste disposal iron compounds are precipitated from the decontaminating liquid. Since the used decontaminating solution contains only Fe.sup.2+ ions, no problems arise in precipitation. The deposits that form have the property of adsorbing the radioactive materials in the solution so that by separation of the deposit very high precipitation decontamination factors are achievable. The separated solid deposit contains then practically all the radioactive materials from the decontaminating solution while the liquid contains at most an unimportant residual activity which lies or may lie beneath the tolerance limit, and thus the liquid may be regenerated for re-use or may be subject to a simple chemical waste disposal by decomposition of the dissolved materials into gaseous products and water, NaOH, and possibly Na.sub.2 CO.sub.3 . The chemical composition of the decontaminating solution provided according to the invention permits the Fe.sup.2+ ions to be precipitated in the form of iron compounds, the density of which roughly corresponds to the density of iron oxide or which can be readily converted into such iron compounds. The radioactive waste obtained by a performed decontamination process is then approximately equal to the material removed from the contaminated surface and thus represents a minimum.
	abstract	The invention relates to a grid holder for an X-ray diagnostic system. The grid holder cooperates with a flexible X-ray grid, which in a flat state has a first focus distance/convergence distance of about 120 cm. A flexing means, preferably in the form of an inflatable element, which can exert a pressure on the surface of the grid, is arranged to flex the grid in a first direction to a first position in which it has a second convergence distance of about 180 cm. Another corresponding flexing means is arranged to flex the grid in the opposite direction to a second position in which it has a third convergence distance of about 80 cm. This allows variable convergence distances with minimum flexing of the grid. The invention also relates to grid devices with grid holders and grids as well as X-ray diagnostic systems comprising such grid holders/grid devices.
	summary
	abstract	A production device and a production method for a grating-type optical component enabling formation of a variety types of FBGs using a single phase mask and an optical component made by the production method or production device for a grating-type optical component are provided. The method involves diffusing at least one of hydrogen or deuterium into an optical fiber and altering the refractive index of the optical fiber by irradiating the fiber with non-interfering UV lamp light.
050230441	description	DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings, it is seen that the invention is generally referred to by the numeral 10. Control assembly 10 is comprised of disk assembly 12 and means 14 for rotating disk assembly 12. As seen in the block diagram of FIG. 1, disk assembly 12 is positioned substantially at the longitudinal center of reactor core 16 and is coaxial with reactor core 16. This divides the core 16 into two subcritical halves when disk assembly 12 is in its fully closed position. As seen in FIG. 3, disk assembly 12 is formed from at least two disks 18, 20. Disks 18, 20 are machined with an identical surface hole pattern 22, 24 such that the rotation of one disk relative to the other causes the hole pattern to open or close. Although hole patterns 22, 24 are shown as being circular, it should be understood that the holes may be in any suitable shape such as sectors or triangles. FIG. 2 illustrates the situation where the disks are rotated s that the hole pattern is closed, that is, the holes 22 provided through first disk 18 are not in alignment with the holes 24 provided through second disk 20 and indicated in phantom view. In the preferred embodiment, the disks 18, 20 are formed from neutron absorbing material such as a cadmium or boron alloy with the holes being a void area. Cadmium and boron have large neutron cross sections as neutron absorbers and are used as alloys well known in the industry. Control of the release of neutrons and core reactivity is accomplished by rotating one of the disks relative to the other to open or close the hole pattern. In FIG. 2, the hole pattern is fully closed. This prevents neutrons in one half of the core from reaching the other half and thus divides the core into two subcritical halves. Rotation of one disk relative to another to cause partial or complete alignment of the holes in the disks allows passage of neutrons therethrough and results in an increase in core reactivity. The level of core reactivity is controlled by and is directly related to the amount of overlap of holes 22 and 24 on disks 18, 20. Means 14 for rotating one disk relative to the other as best seen in FIG. 3(shown with secondary split core control) is mounted adjacent reactor 36. Drive motor 26 is in operative engagement with drive gear 28 through drive shaft 30. Drive gear 28 meshes with gear 32 on disk rotation shaft 34 that extends up through the center of reactor 36. Disk rotation shaft 34 is held in position and rotatably received by retaining nut 38. Fuel elements 40 are rigidly attached between guide plate 42 and first disk 18. Heat pipe 41 is attached to first disk 18 and extends through guide plates 42. The lower guide plate 42 is operatively engaged with disk rotation shaft 34 by means of gear 44 such that plate 42 rotates in response to rotation of disk rotation shaft 34. The rigid connection of heat pipe 41 with guide plate 42 and first disk 18 causes corresponding rotation of first disk 18. Only one fuel element 40 is shown for ease of illustration and it should be understood that a plurality of fuel elements 40 are present in each core half 16 above first disk 18 and below second disk 20. Reactor 36 is shown as the type of reactor wherein the core halves 16 may be moved longitudinally relative to each other to affect reactivity by the use of separation motor 46 and outer drive shaft 48. First control disk 18 is threadably received on the threaded portion 50 of outer drive shaft 48 by thermal fuse 52 such that rotation of outer drive shaft 48 causes first control disk and the upper half of core 16 to move up or down depending on the direction of rotation. Although control assembly 10 is shown as being used in conjunction with movable core halves, it may be used in a reactor where the core halves are stationary. Also, in a reactor with movable core halves, control assembly 10 may be configured to act independently of the core separation mechanism. In operation, first disk 18 is rotated relative to second disk 20 such that holes 22, 24 are not in alignment to maximize neutron attenuation and keep the reactor core halves 16 isolated from each other and subcritical. To allow an increase in reactivity, first disk 18 is rotated so that holes 22, 24 partially or completely overlap depending on the amount of neutron attenuation and core reactivity desired. As seen in the graph of FIG. 4, a test of a control assembly 10 having a series of holes divided into 45 degree sectors produced a minimum neutron count at zero rotation angle(no hole overlap) and a neutron count of approximately 2500 per minute at a rotation angle of 22.5 degrees(total alignment of holes and exposed area of 25.2 percent). This indicates that predictable control of reactivity can be accomplished using control assembly 10. As alternate embdiments, moderating material or fissile material may also be used as part of control assembly 10. Fissile material may be used as inserts in holes 22, 24 to amplify neutron flux through the holes when in the open position to enhance reactivity. Because many varying and differing embodiments may be made within the scope of the inventive concept herein taught and because many modificaitons may be made in the embodiment herein detailed in accordance with the descriptive requirement of the law, it is to be understood that the details herein are to be interpreted as illustrative and not in a limiting sense.
	summary
	claims	1. A method comprising:obtaining a first data series and a second data series, wherein the first data series being associated with values of a parameter sampled from a first system, wherein the second data series being associated with values of the parameter sampled from a second system;calculating a correlation level between the first and second data series;in response to the correlation level being below a predetermined threshold, processing the first and second data series by:repeatedly selecting a transformation from a transformation repository, applying the transformation to the second data series, and computing the correlation level of the first data series and the transformed second data series;selecting, based on the computed correlation levels, the transformation of the plurality of transformations that yields a correlation level above the predetermined threshold; andproviding a recommendation of a modification to the second system based on the selected transformation;wherein the plurality of transformations are associated with an order, and wherein said selecting the transformation from the plurality of transformations is performed based on the order, andreordering the transformations in the transformation repository to reduce computational intensity of the repeated applications;wherein at least one of said calculating, said applying and said providing is performed by a processor. 2. The method of claim 1 further comprising applying the recommendation on the second system, thereby increasing similarity between the first and second systems. 3. The method of claim 1, wherein at least two transformations in the transformation repository differ by a transformation parameter. 4. The method of claim 1 further comprises updating the transformations in the repository in view of a transformation parameter of the selected transformation. 5. The method of claim 1, wherein the order is modified based on user selections over time based on automatic learning. 6. The method of claim 1 further comprises partitioning the first and second data series, wherein the correlation of a first corresponding pair of segments of the first and second data series having a correlation above the predetermined threshold, wherein the correlation of a second corresponding pair of segments of the first and second data series having a correlation below the predetermined threshold, and wherein said processing is performed with respect to the second corresponding pair of segments. 7. The method of claim 6, wherein the recommendation is associated with a portion of a time of execution of the second system. 8. The method of claim 1, wherein the transformations of the repository are configured to simulate configuration change of the second system. 9. The method of claim 1, wherein the first system is a computer system and the second system is a test system. 10. The method of claim 1, wherein the transformations are configured to yield a similarity analysis of respective parameters between the test and the computer systems. 11. The method of claim 1, wherein the correlation level is determined by computing a Pearson product moment of the first and second data series. 12. The method of claim 1, wherein at least some of the transformations comprise at least one of: linear series manipulations; non-linear series manipulations; mapping of at least one of the series from time domain into frequency domain. 13. The method of claim 1, wherein the second data series comprises data points assigned along a unit axis, and wherein at least one of the transformations comprises multiplying the unit axis of the second data series with a specified value. 14. The method of claim 13, wherein the unit axis is associated with time. 15. The method of claim 1, wherein the first and second data series are time series associated with a specified time base. 16. The method of claim 1 further comprising monitoring the first and second systems to sample values of the parameter during execution thereof, wherein said obtaining comprises obtaining the monitored values. 17. A computer program product comprising a non-transitory computer readable medium having instructions retained thereon, which instructions, when provided to a processor, cause the processor to:obtain a first data series and a second data series, wherein the first data series being associated with values of a parameter sampled from a first system, wherein the second data series being associated with values of the parameter sampled from a second system;calculate a correlation level between the first and second data series;in response to the correlation level being below a predetermined threshold, process the first and second data series by:repeatedly selecting a transformation from a transformation repository, applying the transformation to the second data series, and computing the correlation level of the first data series and the transformed second data series;selecting, based on the computed correlation levels, the transformation of the plurality of transformations that yields a correlation level above the predetermined threshold; andproviding a recommendation of a modification to the second system based on the selected transformation;wherein the plurality of transformations are associated with an order, and wherein said selecting the transformation from the plurality of transformations is performed based on the order, andreordering the transformations in the transformation repository to reduce computational intensity of the repeated applications. 18. A computerized apparatus comprising a processor coupled to a memory, wherein said processor is configured to:obtain a first data series and a second data series, wherein the first data series being associated with values of a parameter sampled from a first system, wherein the second data series being associated with values of the parameter sampled from a second system;calculate a correlation level between the first and second data series;in response to the correlation level being below a predetermined threshold, process the first and second data series by:repeatedly selecting a transformation from a transformation repository, applying the transformation to the second data series, and computing the correlation level of the first data series and the transformed second data series;selecting, based on the computed correlation levels, the transformation of the plurality of transformations that yields a correlation level above the predetermined threshold; andproviding a recommendation of a modification to the second system based on the selected transformation;wherein the plurality of transformations are associated with an order, and wherein said selecting the transformation from the plurality of transformations is performed based on the order, and reordering the transformations in the transformation repository to reduce computational intensity of the repeated applications.
050770004	description	DETAILED DESCRIPTION OF THE INVENTION In the following description, like reference characters designate like or corresponding parts throughout the several views. Also in the following description, it is to be understood that such terms as "forward", "rearward", "left", "right", "upwardly", "downwardly", and the like, are words of convenience and are not to be construed as limiting terms. PRIOR ART REACTOR COOLANT PUMP Referring now to the drawings, and particularly to FIG. 1, there is shown a schematic representation of one of a plurality of cooling loops 10 of a conventional nuclear reactor coolant system. The cooling loop 10 includes a steam generator 12 and a reactor coolant pump 14 serially connected in a closed coolant flow circuit with a nuclear reactor core 16. The steam generator 12 includes primary tubes 18 communicating with inlet and outlet plenums 20,22 of the generator. The inlet plenum 20 of the steam generator 12 is connected in flow communication with the outlet of the reactor core 16 for receiving hot coolant therefrom along flow path 24 of the closed flow circuit. The outlet plenum 22 of the steam generator 12 is connected in flow communication with an inlet suction side of the reactor coolant pump 14 along flow path 26 of the closed flow circuit. The outlet pressure side of the reactor coolant pump 14 is connected in flow communication with the inlet of the reactor core 16 for feeding cold coolant thereto along flow path 28 of the closed flow circuit. In brief, the coolant pump 14 pumps the coolant under high pressure about the closed flow circuit. Particularly, hot coolant emanating from the reactor core 16 is conducted to the inlet plenum 20 of the steam generator 12 and to the primary tubes 18 in communication therewith. While in the primary tubes 18, the hot coolant flows in heat exchange relationship with cool feedwater supplied to the steam generator 12 via conventional means (not shown). The feedwater is heated and portions thereof changed to steam for use in driving a turbine generator (not shown). The coolant, whose temperature has been reduced by the heat exchange, is then recirculated to the reactor core 16 via the coolant pump 14. The reactor coolant pump 14 must be capable of moving large volumes of reactor coolant at high temperatures and pressures about the closed flow circuit. Although, the temperature of the coolant flowing from the steam generator 12 to the pump 14 after heat exchange has been cooled substantially below the temperature of the coolant flowing to the steam generator 12 from the reactor core 16 before heat exchange, its temperature is still relatively high, being typically about 550 degrees F. The coolant pressure produced by the pump is typically about 2500 psi. As seen in FIGS. 2 and 3, the prior art reactor coolant pump 14 generally includes a pump housing 30 which terminates at one end in a seal housing 32. The pump 14 also includes a pump shaft 34 extending centrally of the housing 30 and being sealingly and rotatably mounted within the seal housing 32. Although not shown, the bottom portion of the pump shaft 34 is connected to an impeller, while a top portion thereof is connected to a high-horsepower, induction-type electric motor. When the motor rotates the shaft 34, the impeller within the interior 36 of the housing 30 circulates the coolant flowing through the pump housing 30 at pressures from ambient to approximately 2500 psi cover gas with minimum pressurized coolant applies an upwardly directed, hydrostatic load upon the shaft 34 since the outer portion of the seal housing 32 is surrounded by the ambient atmosphere. In order that the pump shaft 34 might rotate freely within the seal housing 32 while maintaining the 2500 psi pressure boundary between the housing interior 36 and the outside of the seal housing 32, tandemly-arranged lower primary, middle secondary and upper tertiary sealing assemblies 38,40,42 are provided in the positions illustrated in FIGS. 2 and 3 about the pump shaft 34 and within the pump housing 30 The lower primary sealing assembly 38 which performs most of the pressure sealing (approximately 2250 psi) is of the non-contacting hydrostatic type, whereas the middle secondary and upper tertiary sealing assemblies 40,42 are of the contacting or rubbing mechanical type. Each of the sealing assemblies 38,40,42 of the pump 14 generally includes a respective annular runner 44,46,48 which is mounted to the pump shaft 34 for rotation therewith and a respective annular seal ring 50,52,54 which is stationarily mounted within the seal housing 32. The respective runners 44,46,48 and seal rings 50,52,54 have top and bottom end surfaces 56,58,60 and 62,64,66 which face one another. The facing surfaces 56,62 of the runner 44 and seal ring 50 of the lower primary sealing assembly 38 normally do not contact one another but instead a film of fluid normally flows between them. On the other hand, the facing surfaces 58,64 and 60,66 of the runners and seal rings 46,52 and 48,54 of the middle secondary and upper tertiary sealing assemblies 40 and 42 normally contact or rub against one another. Because the primary sealing assembly 38 normally operates in a film-riding mode, some provision must be made for handling coolant fluid which "leaks off" in the annular space between the seal housing 32 and the shaft 34 rotatably mounted thereto. Accordingly, the seal housing 32 includes a primary leakoff port 68, whereas leakoff ports 70 accommodate coolant fluid leakoff from secondary and tertiary sealing assemblies 40,42. Also, the reactor coolant pump 14 has an annular fluid blocking splash guard 72 disposed adjacent to an annular collar 74 attached to the pump shaft 34. The splash guard 72 is seated within an annular recess 76 formed about an upper portion 78 of the seal housing 32. Screws 80 (only one of which is shown) threaded into holes 82 tapped in the seal housing portion 78 serve to attach the splash guard 72 to the seal housing 32 and retain it in the recess 76 such that an inner periphery 84 of the splash guard 72 is disposed close to the exterior cylindrical surface 86 of the shaft collar 74. RCP AUXILIARY FFLEXIBLE VACUUM BOOT SEAL OF THE PRESENT INVENTION In accordance with principles of the present invention, an auxiliary flexible vacuum seal 88 can be temporarily installed, without the necessity of removing any parts of the pump 14 other than for some piping (not shown), to prepare the reactor coolant pump 14 for reactor coolant system vacuum degasification. Referring now to FIGS. 4 to 15, the auxiliary flexible vacuum seal 88 basically includes a flexible boot member 90, clamping means 92, and upper and lower sealing portions, preferably in the form of ring elements 4,96 (FIG. 8) on the boot member 90. In the alternative, the sealing portions may be the interior surface of the boot member 90 itself at the opposite open end portions thereof since the boot member 90 is stretched when so installed. Also, preferably, the seal 88 includes a boot support member 98. for allowing flexing of the boot member between open and closed side configurations to permit its installation and removal on and from the pump. The flexible boot member 90 of the seal 88 includes a bowl-shaped body 100 (FIGS. 5, 7 and 8). The body 100 has a pair of longitudinally-displaced opposite end portions 100A,100B and defines a hollow cavity 102 (FIG. 10) open at the opposite end portions The body 100 also has a pair of side-by-side longitudinally-extending side portions in the form of flanges 104 defining a split 106 (FIG. 11) in the boot member body 100 along a side thereof. The split 106 extends between the open end portions 100A,100B rendering the body 100 openable at the split 106 for allowing flexing of the boot member 90 between open and closed side configurations to permit its installation and removal on and from the pump housing 30 and shaft 34. The flanges 104 of the boot member 90 project radially outward from and extend longitudinally along opposite sides of the longitudinal split 106 in the body 100. The flanges 104 are disposed in side-by-side contacting relation when the boot member 90 is in its closed configuration as seen in FIGS. 9 and 11 and displaced from one another when the boot member 90 is flexed to its open configuration. The clamping means 92 of the flexible vacuum seal 88 are operable for releasably and sealably clamping together the flanges 104 of the boot member body 100 at the split 106 to retain the boot member 90 in its closed configuration. As seen in FIGS. 8, 9 and 13-15, the clamping means 92 of the flexible seal 88 includes a pair of brackets 108,110 mountable along outer sides of said flanges 104 on the boot member body 100, and a plurality of fasteners 112 extendible through the brackets. The brackets 108,110 have a series of holes 114 therethrough which are alignable with holes 116 through the flanges 104. Also, nuts 118 are attached to the brackets 108,110 at alternating ones of the holes 114 therein. The fasteners 112 are insertable through the aligned holes 114,116 of the brackets 108,110 and flanges 104. Threading the fasteners 112 into the nuts 118 operates to draw the brackets 108,110 toward one another clamping the flanges 104 therebetween. Unthreading the fasteners 112 from the nuts 118 operates to withdraw the brackets 108,110 away from one another for releasing the flanges 104. Further, the upper and lower sealably engaging portions 94,96 (best seen in FIGS. 10 and 12) on the boot member body 100 at the opposite open end portions 100A,100B thereof are rings being semi-circular in cross-section and projecting radially inwardly, however, as mentioned above, these engaging portions 94,96 may be the interior surface of the boot member body 100. Preferably, the rings 94,96 are formed integrally on the interior surface of the body 100 of the boot member 90, extending circumferentially about the interior and projecting radially inwardly therefrom for sealably engaging the pump housing 30 and shaft 34 when the boot member 90 is installed and flexed to its closed configuration, as seen in FIGS. 4 and 5. The boot member 90 and the sealably engaging rings 94,96 on the opposite end portions 100A,100B thereof are composed of resilient stretchable material such as PVC. The body 90 is in a stretched condition when it is installed and clamped to its closed configuration. In such closed configuration, it permits generation of a vacuum seal condition between the boot member 90 and the pump housing 30 and shaft 34. The body 100 has a port 120 conformable to receive the leakoff 70. Finally, the boot support member 98 (best seen in FIGS. 5, 6 and 7) of the flexible seal 88 is disposable within the boot member 90 between it and the pump housing 30 for supporting the boot member 90 when in its closed configuration. As shown in FIGS. 4 and 5, the boot support member 98 is entirely enclosed and covered by the boot member 90 such that the boot support member 98 merely provides an internal supporting structure for the boot member 98 but does not need to provide a sealing type of engagement therewith. More particularly, the boot support member 98 is annular in shape and split at 122 such that the member 98 is composed of a pair of semi-circular parts 124. The support member 98 also has an upper surface 98A conformed in shape to the relatively smooth surface of an intermediate portion 100C (FIG. 11) of the boot member body 100 being located between its opposite end portions 100A,100B for engagably supporting the boot member 90 at its intermediate portion. Further, the boot support member 98 has a lower surface 98B conformed in shape to the relatively interrupted shape of the pump housing 30 for mounting the support member 98 thereon. It is thought that the present invention and many of its attendant advantages will be understood from the foregoing description and it will be apparent that various changes may be made in the form, construction and arrangement of the parts thereof without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbefore described being merely a preferred or exemplary embodiment thereof.
055085180	description	DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION FIG. 1 shows an E-beam lithography tool 10 with the vibration isolation configuration of the present invention. The E-beam lithography tool 10 can advantageously be a reduction-projection or scanning E-beam system. However, it should be understood that this invention is not limited E-beam lithography. For example, the vibration isolation configuration can also be used with other lithography tools, such as optical tools or the like, as well as inspection tools, such as electron microscopes or the like. The chief objective of the present invention is to isolate the optical components of the tool 10 from vibrations from the floor as well as vibrations produced by moving and/or vibrating components used in the tool itself. The tool 10 includes a ground frame 12 which supports a substrate handling module 14, an exposure module 16, and a stage drive module 18. The important feature of this invention is that the optical subsystem referred to as the exposure module 16 is isolated from the ground, while the substrate handling module 14 and stage drive module 18, which both include sources of vibration, are connected to ground. For example, the substrate handling module 14 includes means for moving wafers 20 in and out of the exposure module 16 as indicated by double ended arrow 22, and means for moving masks 24 in and out of the exposure module 16 as indicated by double ended arrow 26. In addition, vacuum pump 28 is connected to the substrate handling module 14. The means for moving wafers 22, the means for moving masks 24, and the vacuum pump 28 are each connected to ground frame 12 such that vibrations from these components can be directed to ground. Likewise, the stage drive module 18 includes servo motors 30 and 32 for driving the X-Y stages 34 and 36 that move the wafers 20' and masks 24', respectively, within the exposure module 16. In addition, vacuum pump 38 is connected to the stage drive module 18. The servo motors 30 and 32, and the vacuum pump 38 are each connected to the ground frame 28 such that vibrations from these components are directed to ground. By contrast, the exposure module 16, which includes all the optical components needed for lithography, inspection, or the like, is completely isolated from the ground frame 12. FIG. 1 shows an E-beam lithography tool 10 wherein the exposure module 16 comprises an electron column 40, stage plates 42 and 44 for the X-Y stages 34 and 36 for the wafer 20' and mask 24', respectively, and the metrology flamework which includes a suspending member 48, a mask compartment 50, a projection sub-unit 52, and a wafer compartment 54. Bellows 56 and 58 allow wafers 20 and masks 24 to be inserted into and withdrawn from the wafer compartment 54 and the mask compartment 50, respectively. The bellows are preferably made of stainless steel, polymers, or some other suitable material, and are preferably corrugated such that vibrations from the substrate handling module 14 are not transmitted to the exposure module 16 during movement of the wafers 20 and masks 24 into the wafer compartment 54 and mask compartment 50, respectively. Bellows 60 and 62 allow the X-Y stages 42 and 44 to be controlled within the wafer compartment 54 and mask compartment 50, respectively, by servo motors 30 and 32, using drive arms 64 and 66, or the like. The bellows 60 and 62 are preferably made from similar materials to those described in conjunction with bellows 56 and 58, and have a similar corrugated configuration. The bellows 56, 58, 60, and 62 provide high vacuum connections between the exposure module 16 and adjacent modules 14 and 18, and are heavily damped to prevent vibrations from being transmitted to said exposure module 16 from the substrate handling module 14 or stage drive module 18. Interposed between the suspending member 48 and the frame portions of the substrate handling module 14 and stage drive module 18 are vibration isolation components 64 and 66. The isolation components 64 and 66 serve to prevent mechanical vibrations from being transmitted to the exposure module. The isolation components can be of the type which are commercially available from Barry Controls, Newport, or Integrated Dynamics Engineering. Vibrations emanating from ground, such as those that are transmitted along a factory floor, can be dissipated by vibration damping devices 68 which can be rubberized pads or the like. However, because the exposure module 16 is isolated from ground as described above, vibration damping from ground sources is not required. While the invention has been described in terms of its preferred embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the appended claims.
	abstract	A charged particle beam therapy apparatus includes an accelerator accelerating a charged particle and emitting a charged particle beam, an irradiation unit irradiating an irradiation subject with the charged particle beam, and a ridge filter provided in the irradiation unit and generating a spread out Bragg peak of the charged particle beam. The ridge filter includes multiple damping members reducing energy of the incident charged particle beam, in an intersecting direction intersecting an irradiating direction of the charged particle beam. The damping member has a cross-sectional area changing along the irradiating direction and has a side surface of when being seen in the intersecting direction, being bonded to a side surface of another damping member. A pass-through portion passing through the ridge filter in the irradiating direction is formed at a position different from a position of the damping member of when being seen in the irradiating direction.
	abstract	A radiation imaging apparatus comprising a detection unit for detecting a radiation distribution transmitted through an object, an imaging unit which includes the detection unit, and a grid for suppressing scattered light which is detachably mounted on an outside of the imaging unit, wherein the imaging unit includes a buffer member on a side surface facing a surface side which radiation strikes, the grid includes a grid body placed on the surface side which the radiation strikes, and a fixing unit for fixing the grid body to the imaging unit, and sides constituting the fixing unit include a side which does not protrude from an outer shape of the imaging unit when viewed from the surface side which the radiation strikes.
047939630	claims	1. In a nuclear reactor core having a multiplicity of fuel assemblies, a method of fuel interchange between said fuel assemblies, comprising the steps of: (a) inserting a cluster assembly of a first plurality thereof, with each cluster assembly of said first plurality containing an array of fuel rods having burnt fuel disposed therein, into a fuel assembly of a first plurality thereof, with each fuel assembly of said first plurality containing an array of fuel rods having fresh fuel disposed therein; and (b) inserting a cluster assembly of a second plurality thereof, with each cluster assembly of said second plurality containing an array of fuel rods having fresh fuel disposed therein, into a fuel assembly of a second plurality thereof, with each fuel assembly of said second plurality containing an array of fuel rods having burnt fuel disposed therein; (c) certain groups of said fuel rods in each fuel assembly being spaced apart laterally from one another by a greater distance than the rest of said fuel rods so as to define a plurality of empty elongated channels in an array being interspaced within said array of fuel rods, each elongated channel being in the form of an open space extending laterally between and longitudinally along said fuel rods of said certain groups thereof; (d) said fuel rods of each cluster assembly in each of said first and second pluralities thereof being larger in size than said fuel rods of each fuel assembly in each of said first and second pluralities thereof, said larger size cluster assembly fuel rods being inserted in said elongated channels defined in said respective fuel asssemblies. (a) first and second pluralities of said fuel assemblies, said fuel assembly in each plurality thereof having an array of elongated fuel rods therein , certain groups of said fuel rods in each fuel assembly being spaced apart laterally from one another by a greater distance than the rest of said fuel rods so as to define a plurality of empty elongated channels in an array being interspaced within said array of fuel rods, each elongated channel being in the form of an open space extending laterally between and longitudinally along said fuel rods of said certain groups thereof, said fuel rods in said first and second pluralities of fuel assemblies containing fresh and burnt fuel respectively; and (b) first and second pluralities of cluster assemblies, said cluster assembly in each plurality thereof containing an array of elongated fuel rods being disposed in a pattern which matches that of said channels being interspaced within said array of fuel rods of each fuel assembly; (c) said fuel rods of said first plurality of cluster assemblies containing burnt fuel therein and being removably inserted in a first group of said channels within said first plurality of fuel assemblies; (d) said fuel rods of said second plurality of cluster assemblies containing fresh fuel therein and being removably inserted in a second group of said channels within said second plurality of fuel assemblies; (e) said fuel rods of each cluster assembly in each of said first and second pluralities thereof being larger in size than said fuel rods of each fuel assembly in each of said first and second pluralities thereof. 2. The fuel interchange system as recited in claim 1, wherein said fuel rods of each cluster assembly are larger in diameter than said fuel rods of each fuel assembly. 3. The fuel interchange system as recited in claim 1, wherein said fuel rods of each cluster assembly are greater in length than said fuel rods of each fuel assembly. 4. In a nuclear reator core having a multiplicity of fuel assemblies, a system of fuel interchange between said fuel assemblies, comprising: 5. The fuel interchange system as recited in claim 4, wherein said fuel rods of each cluster assembly are larger in diameter than said fuel rods of each fuel assembly. 6. The fuel interchange system as recited in claim 4, wherein said fuel rods of each cluster assembly are greater in length than said fuel rods of each fuel assembly.
048760625	description	DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention has been achieved on the basis of the results of investigations conducted by the inventors with respect to the characteristics of conventional fuel assemblies. As a result of these investigations, the inventors have found that an increase in the degree of burn-up of a fuel assembly requires improvements in fuel economy and thermal allowance. Particular reference is made to the fuel assembly shown in FIG. 2 of Japanese Patent Laid-Open No. 178387/1984 in which moderating rods each having a square sectional form are arranged in the shape of a cross at the center, and a minimal space is formed between a fuel spacer lattice and the moderating rods so that the moderating rods can be easily inserted or extracted. This fuel assembly aims at effective use of fuel by allowing the moderating rods to be inserted or extracted the moderating rods during the operation of a reactor. However, cooling water flowing in the spaces between the adjacent moderating rods contributes to removal of heat from the fuel rods to slight degrees and thus decreases the thermal allowance in the conventional fuel assembly. As a result of investigations conducted by the inventors with respect to the structure of a fuel assembly capable of solving the above-described problem, the inventors have reached the conclusion that it is desirable for the ration A.sub.M /A.sub.C of the area A.sub.M of a moderator region in a moderating rod in the cross-sectional plane containing a moderator to the area of a coolant passage in a fuel assembly to be kept within the range of 0.07 to 0.11, and for the area A.sub.M to be 75% or more of the total area A.sub.U of fuel lattice units where a moderating rod is disposed, but in which no fuel rods are arranged, as described above. The range of the ratio A.sub.M /A.sub.C is first described below. FIG. 1 shows the relationship between the ratio A.sub.M /A.sub.C and the effect of saving uranium. One water rod is used as a moderating rod. The cross-sectional area A.sub.M of a moderator region in the moderating rod is the cross-sectional area of a water region in the water rod. The cross-sectional area A.sub.C of a coolant passage is the area of a coolant passage in the cross-sectional plane of a fuel assembly and contains none of the cross-sectional area of a saturated water region (moderator region) in the water rod. With the ratio A.sub.M /A.sub.C within the range of 0.07 to 0.11, the effect of saving uranium is large, and, with the ratio at 0.09, the effect of saving uranium at its the maximum level. As the moderator region in the moderating rod is increased, the ratio of fuel to the moderator is increased and the effect of slowing down neutrons at the center of a fuel assembly is also increased. Therefore, the non-uniformity in the distribution of thermal neutron fluxes in the fuel assembly is reduced, and the non-uniformity is particularly remarkably remarkably reduced with the ratio A.sub.M /A.sub.C at 0.07 or more. Consequently, neutrons can be effectively employed in nuclear fission reaction, and, as shown in FIG. 1, the effect of saving uranium is increased with the ratio A.sub.M /A.sub.C being 0.07 or more. However, when the area of the moderator region in the moderating rod is increased and the ratio A.sub.M /A.sub.C becomes over 0.11, the above-described effect is greatly reduced. This is because the ratio of moderator to fuel becomes too large and the absorption of neutrons by the moderator is increased, and also because the amounts of fuel materials charged (fertile material and fissionable material) must be reduced in order to secure the area of a coolant passage in the fuel assembly and thus to prevent any increase in the pressure loss. A description will now be made of the area A.sub.M which is preferably 75% or more of the total area of a plurality of fuel lattice units. In FIG. 2, the axis of abscissas is the ratio of the area A.sub.M of a saturated water region in the a rod to the total area A.sub.U of fuel lattice units where no fuel rods are arranged but in which a water rod is disposed, and the axis of ordinate is the critical power of a fuel assembly. Such relationships are shown by using the number (5 to 9) of the above-described fuel lattice units as a parameter. If the ratio of the area A.sub.M to the area A.sub.U is 75% or more, the rate of increase in the critical power of the fuel assembly is larger than that in the case of the ratio is below 75%. However, if the ratio of the area A.sub.M to the area A.sub.U is over 90%, the critical power of the fuel assembly starts to decrease. This is because the cross-sectional area (total cross-sectional area of the area A.sub.M and the area of a hollow rod which is a constituent member of the water rod and in which a saturated water region is present) of the water rod containing the hollow rod becomes greater than the area A.sub.U, and the space formed between each of the sides of the water rod and the fuel rods adjacent to the water rod is reduced, with the coolant flows near the fuel rods being consequently reduced. It is therefore preferable that the area A.sub.M is 75% or more of the area A.sub.U. In FIG. 2, with the ratio of the area A.sub.M to the area A.sub.U at 90% or more, the critical power of the fuel assembly is at its maximum value. The reasons for this are described below. (1) In general, if the cross-sectional area of a water rod is changed, the area of a coolant passage and the length of a wetted side change also. Thus, the flow of coolant and the quality distribution vary. (2) Since, the gap between a water rod nd a fuel rod is sufficiently large if the ratio A.sub.U /A.sub.M is small, boiling transition takes place in, for example, fuel rods in the vicinity of a channel box, in the same way as a case in which no water rod is present. (3) Since, the area of a cooling water passage around a water rod is reduced if the ratio A.sub.U /A.sub.M is increased cooling water flows relatively easily around a channel box, and the thermal allowance of the fuel rods in the vicinity of the channel box is thus increased. While in the periphery of the fuel rods adjacent to a water rod, the flow of cooling water is reduced, and quality is increased, whereby boiling transition is facilitated. (4) Therefore, if the cross-sectional area of a water rod is changed, the thermal allowance of a fuel assembly becomes maximal when the thermal allowances of the fuel rods in the vicinity of the water rod and in other portions are the same, because of the above-described changes in these thermal allowances. In addition, in FIG. 2, M.sub.1, M.sub.2, M.sub.3 and M.sub.4 denotes the points at which the ratios A.sub.M /A.sub.C are each at 0.09 in the cases in which the numbers of the fuel lattice units replaced by a water rod are 5, 6, 7 and 9, respectively. When the number of the fuel lattice units is 9, the ratio of the area A.sub.M to the area A.sub.U is extremely decreased to a value of below 75% in order to attain the ratio A.sub.M /A.sub.C at 0.09. In addition, when the number of fuel lattice units is 9, the ratio of the area A.sub.M to the area A.sub.U is below 75% with the ratio A.sub.M /A.sub.C shown in FIG. 1 which is within the range of 0.07 to 0.11. When the number of fuel lattice units is 7, the ratio of the area A.sub.M to the area A.sub.U is below 75% at the point at which A.sub.M /A.sub.C =0.09, but there is a region in which the ratio o(the area A.sub.M to the area A.sub.U is 75% or more within the range with the ratio A.sub.M /A.sub.C which is within the range of 0.09 to 0.11. Therefore, the number of fuel lattice units replaced by a water rod is preferably 5 to 7. A preferred embodiment of a fuel assembly of the present invention which is applied to a boiling water reactor is described below with reference to FIGS. 3 and 4. A fuel assembly 10 comprises an upper tie plate 3, a lower tie plate 14, a plurality of fuel rods 15 which are held by the upper and lower tie plates at their ends, fuel spacers 16 for keeping the width of a gap between the respective fuel rods at a given value, and a water rod 17 which is provided on the lower tie plate 14. A plurality of the fuel spacers 16 are arranged in the axial direction of the fuel assembly 10 and hold the fuel rods 15 and the water rod 17. A channel box 11 is provided on the upper tie plate 13 and surrounds the outside of a bundle of the fuel rods 15 bundled by the fuel spacers 16. The water rod 17 has the cross section of a cruciate form and is placed at the center in the cross-sectional plane of the fuel assembly 10, as shown in FIG. 4. Six kinds of fuel rods 21 to 26 are provided as the fuel rods 15. The enrichment and the concentration of gadolinium which is a burnable poison of each of the fuel rods is shown in Table 1. The fuel rods 25 and 26 contain gadolinium, and the fuel rods 21 to 24 contain no gadolinium. The enrichment of the fuel rod 21 is 3.2 wt. %, the enrichment of the fuel rod 22 is 3.8 wt. %, the enrichment of the fuel rods 23, 25 and 26 is 4.4 wt. %, and the enrichment of the fuel rod 24 is 4.8 wt. %. TABLE 1 ______________________________________ Numeral of fuel rod 21 22 23 24 25 26 ______________________________________ Enrichment 3.2 3.8 4.4 4.8 4.4 4.4 (wt. %) Gadolinium -- -- -- -- 4.5 3.5 (wt. %) Number 4 8 24 24 12 4 ______________________________________ The average enrichment of the fuel assembly 10 is 4 wt. %, and gadolinium is contained in the fuel rods 25 and 26 in the concentrations of 4.5 wt. % and 3.5 wt. %, respectively. The fuel assembly 10 has the cross section of a square form. The fuel rods 15 are arranged in the periphery of the fuel assembly 10 in a matrix having 9 rows and 9 columns so as to surround the water rod 17. In other words, the fuel rods 15 are arranged between the sides of the water rod 17 and the sides of the fuel assembly 10 (for example, the sides of the channel box 11). Light water serving as cooling water flows into the spaces between the respective fuel rods 15 in the channel box 11 from the lower tie plate 14, upwardly passes through the spaces between the respective fuel rods 15 and the fuel rods 15 and the water rod 17, and flows out to the outside of the fuel assembly through the upper tie plate 13. As shown in FIG. 5, the water rod 17 has a cross-shaped hollow rod 17A which has a moderator region containing light water (specifically saturated water) serving as a moderator. The moderator region has a the cruciform cross-section. The width of each of projecting portions of the cruciform hollow rod 17A (the distance W between external walls of the hollow rod 17A) is 1.4 cm which is the same as the pitch of the fuel rods 15. The wall thickness of the hollow rod 17A is 0.08 cm. Therefore, the cross-sectional area of the moderator region having a cruciate form in the water rod 17 is 8.48 cm.sup.2. Portion S shown in FIG. 4 denotes the shape of a fuel lattice unit. This fuel lattice unit S has a square form having sides which each have the same length as the pitch (1.4 cm) of the fuel rods 15. The fuel assembly 10 of this embodiment comprises 9 fuel lattice units S in the direction shown by J and 9 lattice units S in the direction shown by I, as shown in FIG. 4. The water rod 17 occupies the five fuel lattice units S of (4, 5), (5, 4), (5, 5), (5, 6) and (6, 5) which are each denoted by (I, J). In this embodiment, the ratio of the area A.sub.M of the moderator region in the water rod 17 to the total area A.sub.U of the five fuel lattice units S where the water rod 17 is disposed, but in which no fuel rods 15 are arranged, is 86.5%. The average ratio (H/U) of the number of hydrogen atoms to the number of uranium atoms of the fuel assembly 10 is about 5.0 which is an optimum value for the enrichment of 4 wt. % from the viewpoint of nuclear properties. In this embodiment, the ratio A.sub.M /A.sub.C of the area A.sub.M of the moderator region in the cross-sectional plane of the fuel assembly 10 in which the moderator region of the water rod 17 is present to the area A.sub.C of the passage for the cooling water in the fuel assembly 10 is 0.09. The area A.sub.C of the passage for the cooling water is the area of the passage for the cooling water in the channel box 11 and contains no area of the moderator region in the water rod 17. The configuration of the water rod 17 is described in detail below with reference to FIGS. 5 to 8. The water rod 17 is made of Zircalloy-2 and comprises the hollow rod 17A having a cruciform cross-section and a cylindrical member 17B and a lower end plug 17C which are provided at the lower end of the hollow rod 17A. The upper end of the hollow rod 17A is placed near the upper end of a region charged with fuel pellets for the fuel rods 15, i.e., the fuel effective length. The cylindrical member 17B is inserted into the lower end of the hollow rod 17A and is fixed to a portion 17D of contact with the hollow rod 17A by solding. The lower end plug 17C seals the lower end of the cylindrical member 17B. The lower end plug 17C is provided on the lower tie plate 14 so that the water rod 17 is held in the fuel assembly 10. The cylindrical member 17B is so configured as to reinforce the interior of the hollow rod 17A. Since the cylindrical member 17B functions to increase the strength of the water rod 17 and to absorb neutrons, it is used only in the lower portion of the water rod 17. The lower end of the hollow rod 17A has a surface 17F inclined to the cylindrical member 17B. The provision of the inclined surface 17F causes the area of the passage for the cooling water to gradually change from the lower end of the fuel assembly 10 to the upper end thereof and thus prevents an increase in the pressure loss due to a rapid contraction flow. Cooling water inlets 17E for introducing the light water sering as the cooling water (also serving as a moderator), which flows into the channel box 11, into the water rod 17, i.e., the hollow rod 17A, are provided in the inclined surface 17F of the hollow rod 17A. Cooling water outlets 17G for discharging the cooling water to the outside of the water rod are provided in the hollow rod 17A. As shown in FIG. 5, cylindrical reinforcing members 17H are provided in the hollow rod 17A in an upper portion of the water rod 17. Each of the reinforcing members 17H has a small axial length (for example, 3 to 4 cm and is provided on the four concave portions 17I of the hollow rod 17A by soldering. The upper end of the hollow rod 17A is sealed (not shown). The reinforcing members 17H are provided at, for example, 3 to 5 positions in the axial direction of the water rod 17 so as to increase the strength of the water rod 17, i.e., so as to prevent the hollow rod 17A from expanding outward. The water rod 17 effectively acts on a portion in the fuel assembly 10 in which the cooling water in the passage produces bubbles in a saturated state. However, the cooling water is in an unsaturated state at the lower end of the fuel assembly 10, and it is thus not significant that the water rod 17 is present at the lower end thereof. In addition, the water rod 17 having a large cross section tends to reduce the area of the cooling water passage in the fuel assembly 10 and thus to increase the pressure loss, or increase the amount of neutrons absorbed because of an increase in the amount of the structural members required. It is therefore preferable that the cross-section of the water rod 17 is small in a lower portion of the fuel assembly 10. In this embodiment, the cross-section of the cylindrical member 17B is smaller than that of the cruciform of the hollow rod 17A, whereby the pressure loss in a lower portion of the fuel assembly 10 can be reduced. The region of unsaturated water in a lower portion of the fuel assembly 10 is generally within the range of 30 to 60 cm upward from the lower tie plate 14. In this embodiment, therefore, the length L of the portion of the water rod 17 having a small cross section shown in FIG. 5 is 40 cm. A description will now be made of the function of the cylindrical member 17B which serves as a reinforming member in the lower portion of the water rod 17. The maximum relative stress produced when pressure of 10 atm is applied to the hollow rod 17A from the outside thereof is 15.4 kgf/mm.sup.2 if the hollow rod 17A is not reinforced by the cylindrical member 17B, and is 2.6 kgf/mm.sup.2, which is about 1/6 of the above-described value, if the hollow rod 17A is reinforced by the cylindrical member 17B. The maximum amount of deformation produced when the cylindrical member 17B is present is about 1/30 of that produced if no cylindrical member 17B is present. Since the reinforcing member 17H is also provided, the strength of the water rod 17 is increased. The amount of neutrons absorbed by the reinforcing member 17H can be reduced by making the wall thickness of the reinforcing member 17H smaller than that of the cylindrical member 17B. A moderating rod comprising a solid moderator such a zirconium hydride or beryllium may be used as a moderating rod in place of the water rod. In order to show the effect of this embodiment, the fuel assembly shown in FIG. 9 is conceived in which the cruciform water rod 17 shown in FIG. 4 is replaced by five water rods 28 each having a circular cross sectional form. The enrichment and the gadolinium distribution of each fuel rod are the same as those employed in the embodiment of the present invention. When the outer diameter of each of the water rods 28 is the same as that of each of the fuel rods 15, the total cross-sectional area of moderator regions in the five water rods is about 4.5 cm.sup.2 which is about half that of the embodiment of the present invention. As a result, the neutron infinite multiplication factor of the fuel assembly 10 of the embodiment of the present invention is about 0.4% .DELTA.k.infin. greater than that of the fuel assembly shown in FIG. 9, with the amount of necessary natural uranium being reduced by about 2%. The critical power ratio, which indicates thermal allowance relative to boiling transition, of the fuel assembly 10 of the embodiment of the present invention is 4.3% greater than that of the fuel assembly shown in FIG. 9. FIG. 10A shows the distribution of the flows of the cooling water in the region surrounded by positions C.sub.1 C.sub.2 and C.sub.3 of the embodiment of the present invention (FIG. 4), and FIG. 10B shows the distribution of the flows of the cooling water in the region surrounded by positions D.sub.1, D.sub.2 of the fuel assembly shown in FIG. 9 (the numerical values are normalized so that the average value of each of the fuel assemblies is 1.0). The distribution of the cooling water flows in the embodiment of the present invention is even, as shown in FIG. 10A, while in the assembly shown in FIG. 9 using the water rods 18 having a circular cross-sectional form, the flows of the cooling water around the water rods 18 are large and the flows near the position D.sub.1 close to the channel box are as small as 84% of the average value. Therefore, boiling transition easily takes place in the fuel rods positioned around the water rods 18. In the fuel assembly shown in FIG. 2 of Japanese Patent Laid-Open No. 178387/1984 (not shown in the drawings), the flows of cooling water around a water rod having a square cross-sectional form placed at the center are large and the flows near a channel box are small, in the same way as in the fuel assembly shown in FIG. 9. However, the degree of the drift of the cooling water flows in the fuel assembly disclosed in Japanese Patent Laid-Open No. 178387/1984 is smaller than that in the fuel assembly shown in FIG. 9, but is larger than that in the fuel assembly 10 of the embodiment the present invention. Since the embodiment of the present invention exhibits a remarkable effect in terms of savings of the uranium consumption and the improved fuel economy and shows an even distribution of the cooling water flows in the fuel assembly, the critical power ratio of the fuel assembly is increased, and the degree of thermal allowance thereof is improved. The embodiment of the present invention shows a greater effect in terms of saving the uranium consumption and a greater critical power ratio than those of the fuel assembly shown in FIG. 2 of Japanese Patent Laid-Open No. 178387/1984. A description will now be made of the characteristic function obtained when the outer sides of the water rod and the cross section of the moderator region therein both have a cross shape, as in the embodiment of the present invention. FIG. 11 shows a comparison of the relationship between the number of fuel lattice units contained in the moderator region in the moderating rod and the cross-sectional area of he moderator region in the case of a moderating rod comprising circular units with those in the case of a moderating rod comprising square units. As seen from FIG. 11, the cross section of the moderator region in the moderating rod comprising square units can be made about 30% larger than that in the moderating rod comprising circular units. In other words, in order to obtain an optimum cross-sectional area of the moderator region, the number of the fuel rods required to be removed for providing the moderating rod comprising circular units is 1.4 time that for providing the moderating rod comprising square units. Therefore, when fuel rods comprising circular units are used, the linear power density of each fuel rod is increased, or the amount of fuel materials loaded is reduced, resulting in a loss of the fuel economy. In addition, when the moderating rod comprises circular units, a large coolant passage is formed between the moderating rod and each of the fuel rods, and a large amount of coolant having a small effect of removing heat flows through the passage, resulting in a reduction in the minimum critical power ratio by about 2%. FIG. 12 shows the relationship between the length 1 of one side of a square unit, the cross-sectional area .omega..sup.2 of the moderator region, and the cross-sectional area L.sup.2 of the fuel lattice unit S, in the moderating rod comprising square units. In this case, the wall thickness of a covering tube for the moderating rod is 0.76 mm. When the moderator region comprises a plurality of moderators, the size of the moderating rod is limited from the viewpoint of insertion of the moderating rod, and thus rate of the cross section of the covering tube is increased. The present minimum value of (L-1)/2 shown in FIG. 12 is about 0.5, and the cross-sectional area of the moderator region which can be secured by the moderating rod cannot be made 75% or more the cross-sectional area of the fuel lattice unit S. On the other hand, when one large moderating rod is used, as the embodiment shown in FIG. 4, since there is no region of the cooling water which does not attribute to the cooling of fuel and which is present between moderating rods, the cross-sectional area of the moderating rod can be made 75% or more of the total area of the fuel lattice units in which the fuel rods removed for providing a moderating rod are placed. Consequently, in order to attain an optimum cross-sectional area of the moderator region for the fuel assembly comprising fuel rods which are arranged in a lattice form having 9 rows and 9 columns and comprising the fuel lattice units S that each have the length L of one side of 1.4 cm, fuel rods may be removed from five fuel lattice units S in the embodiment shown in FIG. 4, while fuel rods must be removed from 6 to 7 fuel lattice units in the case comprising a plurality of moderating rods. In addition, in the fuel assembly 10, since there is no coolant which exhibits a small effect of cooling and flows through gaps between moderating rods, no problem with respect to an decrease in the critical power ratio occurs, as described above. FIG. 13 shows the distribution of the thermal neutron fluxes in the fuel assembly. At position at which thermal neutron fluxes are small, the effect of moderating neutrons is poor and reactivity is low. A comparison of a curve OA (in the direction OA of the fuel assembly shown in an upper right portion in the same figure) with a curve OB (in the direction OB of the fuel assembly shown in an upper right portion in the same figure) shows that the thermal neutron fluxes in the direction OA are smaller than those in the direction OB. This is because the fuel rods in the direction OB are affected by gap water regions in two directions. Therefore, the cross shape of the water rod 17 is preferably arranged so as to be at right angles with respect to the sides of the fuel assembly 10, i.e. the sides of the channel box 11. FIG. 14 shows a comparison of the relationship between the number of the fuel lattice units in the moderator region and the number of the fuel rods, which surround the moderating rod and are adjacent thereto, with respect to the cross-sectional shapes of the moderating rods. In the cross-shaped water rod 17 of the embodiment shown in FIG. 4, all the fuel lattice units S which are contained in the moderator region and in which no fuel rods 15 are arranged are always adjacent to the fuel rods 15 surrounding the water rod 17. Therefore, the number of the fuel rods surrounding the water rod is increased, as compared with the case in which the entire cross sectional form of the moderating rod is a square. As a result, the affects described below can be obtained. (i) The rate of utilization of neutrons is increased, and the fuel economy is improved, and (ii) lattice positions adjacent to the water rod 17 can be employed as positions at which fuel rods containing gadolinium as a burnable position are arranged. FIG. 15 shows the coefficients of local power peaking in the assembly 10 provided with the water rod 17 in which the cross section of the moderator region has a cruciate form (fuel rods have the same enrichment and contain no gadolinium). Each of the squares shown in FIG. 5 corresponds to one fuel rod. The fuel rod (denoted by K in FIG. 15) which is adjacent to the water rod 17 and faces two sides surfaces thereof and the outermost fuel rods (denoted by J in FIG. 15) which are adjacent to water gaps (i.e., the channel box) provided around the fuel assembly in a reactor core exhibit higher levels of power peaking. The other fuel rods show lower levels of power peaking than those of the above-described fuel rods. By setting the degree of enrichment of the fuel rods excluding the fuel rods containing gadolinium so as to be in the order of the fuel rods J< the fuel rod K< the other fuel rods for the purpose of increasing the thermal allowance of this fuel assembly, the power distribution in the cross-sectional plane of the fuel assembly can be made even. That is, if the average enrichment of the fuel rods of said fuel rods (15) arranged in the periphery of said fuel assembly is E.sub.A, the average enrichment of the fuel rods which are adjacent to said moderating rod (17) and each face the two sides thereof is E.sub.B, and average the enrichment of the other fuel rods (25) is E.sub.C, the inequality EA<E.sub.B <E.sub.C is established. FIG. 16 shows another embodiment of the fuel assembly of the present invention. A fuel assembly 10A of this embodiment has the same structure as that of the above-described fuel assembly 10 with the exception that the shape of a water rod 29 is different therefrom. In the fuel assembly 10A, the water rod 29 is arranged at the center thereof in the same was as in the fuel assembly 10. The water rod 29 also has a cruciate cross-sectional form, but is different from the water rod 17 with respect to the portions in the water rod 29 which correspond to the concave portions 17I of the hollow rod 17A in the water rod 17 and which are projected toward the fuel rods adjacent to these portions so that the distance between each of the fuel rods and the sides of each of the concave portions is constant. Such a configuration increases the cross-sectional area of a moderator region in the water rod 29 by about 0.5 cm.sub.2 as compared with that in the water rod 17. Therefore, the effect of saving the uranium consumption of the fuel assembly 10A is greater than that of the fuel assembly 10. In this embodiment, the number of the fuel lattice units S in which the water rod 29 is disposed, but in which no fuel rods are arranged, is the same as that in the fuel assembly 10. In addition, since there is no useless passages of cooling water which are shown by E.sub.1 to E.sub.4 in FIG. 16 and produced around the water rod 29, the thermal allowance for boiling transition is 0.4% greater than that of the fuel assembly 10. The water rod 29 comprises a hollow rod 29A which has a cruciate cross-sectional form and rounded concave portions 29F, as shown in FIGS. 17 and 18. A prismatic member 29B having a square cross-sectional shape is passed through the hollow rod 29A. The lower end of the prismatic member 29B is provided with an end plug 29C which is provided on a lower tie plate 14. The lower end of the hollow rod 29A has an inclined surface 29E in the same was as the water rod 17, the inclined surface 29E having a plurality of inlets 29D of cooling water. The use of the prismatic member 29B in place of the cylindrical member 17B has an advantage in that the amount of the constituent members thereof can be reduced as compared with the cylindrical member 17B because points 29I of constant between the prismatic member 29B and the hollow rod 29A are connected by the shortest lines, whereby the absorption of neutrons can be reduced. FIG. 19 shows another embodiment of the prismatic member 29B used in the water rod 29. A prismatic member 29G of this embodiment has a plurality of holes 29H in a number within a range which will not remarkably reduce its structural strength. The provision of the holes 29H reduces the amount of a constituent of the prismatic member so as to reduce the amount of neutrons absorbed. Such a structure is not specific only to the prismatic member 29B, but can also be applied to the cylindrical member 17B. FIGS. 20 and 21 show another embodiment of the water rod used in the fuel assembly 10 or 10A. A water rod 30 of this embodiment comprises a cylindrical member 17B having end plugs 17C which are respectively provided on an upper tie plate 13 and lower tie plate 14. This embodiment is different from the water rod 29 in the point that the cylindrical member 17B is not passed through a portions. Such a structure has the effects in terms of a reduction in the amount of the structural member at the center of the water rod 30 in the axial direction thereof, and thus a reduction in the amount of neutrons absorbed. Such a structure can also reduce a pressure loss at the upper and lower ends of the fuel assembly. The above-described embodiments concern the water rods serving as neutron moderating rods which was unsaturated water, but they can be applied to a neutron moderating rod using a solid moderator. A reinforcer can be provided in a region between support members 120, 121, as occasion demands. A further embodiment of the fuel assembly which is applied to a boiling water reactor is described below with reference to FIG. 22. A fuel assembly 37 of this embodiment is applied to the case in which the thicknesses of gap regions are not constant around a channel box 11. Fuel rods 31 to 36 used in the fuel assembly 37 of this embodiment have the enrichment shown in Table 2. The fuel rods 35 and 36 contain gadolinium. Reference numeral 38 denotes a cross-shaped water rod. The axis of the water rod 38 is located at a position shifted to the side of a shinner gap region (shown by N in FIG. 22). The cruciate shape of the water rod 38 has a shorter length on the side N and a longer length on a side W. Consequently, the distribution of neutron fluxes can be effectively made even, and the fuel economy and thermal allowance can be improved as compared with conventional fuel assemblies. TABLE 2 ______________________________________ Numeral of fuel rod 31 32 33 34 35 36 ______________________________________ Enrichment 3.0 3.6 4.4 4.8 4.4 4.4 (wt. %) Gadolinium -- -- -- 4.5 3.5 (wt. %) Number 3 11 20 24 12 4 ______________________________________ This invention is capable of improving the fuel economy by an increase in the effect of saving uranium, and increasing the thermal allowance by an increase in the critical power ratio of a fuel assembly.
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059303182	summary	TECHNICAL FIELD The present invention relates to a method and a device for handling fuel assemblies in a light-water nuclear reactor comprising a reactor vessel with a reactor core. More particularly, the invention relates to the handling of fuel assemblies which occurs when fuel assemblies are replaced or moved to a new position when the reactor vessel or parts connected thereto are serviced and therefore have to be emptied of fuel assemblies. DESCRIPTION OF RELATED ART A light-water nuclear reactor plant comprises a reactor vessel which encloses a reactor core. The reactor core comprises a large number of fuel assemblies. More particularly, the core normally comprises between 400 and 1000 fuel assemblies. A fuel assembly comprises a bundle of fuel rods. The fuel rods in turn comprise pellets of a nuclear fuel. A coolant in the form of water is arranged to flow from below and up through the core to cool the fuel rods while nuclear fission is in progress. The heated coolant is evaporated whereupon it is passed to a turbine for conversion into electric energy. After a certain burnup time of the fuel assemblies, it is normal either to reject them or to rearrange them within the fuel core in order to burn them out further. Such a refuelling or rearrangement of fuel takes place upon shutdown of the nuclear power plant. During the shutdown, work is normally also carried out in the reactor vessel and in other systems which are connected to the reactor vessel. Such a shutdown is very costly and takes approximately three to eight weeks. Therefore, it is desirable to do whatever is possible to shorten this shutdown time to the shortest possible time. The refuelling in a nuclear power plant thus comprises (a) replacing burnt-up fuel assemblies with new ones, and (b) rearranging a large number of fuel assemblies in the core to obtain optimum burnup. During refuelling, the fuel assemblies are normally handled one by one. When the reactor vessel is opened to make the fuel assemblies accessible, a handling tool is moved down into the core and is brought to grip a fuel assembly which is to be temporarily placed in a fuel pool. Normally, control rods arranged between the fuel assemblies are left in the reactor vessel. Additional fuel assemblies are lifted out of the core and placed at an arbitrary locations in the pool. Thereafter, new fuel assemblies are lifted from the pool into the reactor vessel to the new empty positions. The fuel assemblies are thus lifted one by one. The fuel assemblies which are to be rearranged within the core are normally moved directly from their old to their new positions. In the event that work has to be carried out in the reactor vessel or in adjacent systems, such as pumps directly connected to the reactor vessel, a suitable number of fuel assemblies have to be lifted out therefrom and be temporarily placed at an arbitrary location in the fuel pool. In certain cases, the whole reactor vessel may have to be emptied of fuel assemblies. The lifting of the fuel assemblies one by one out of and into the reactor vessel, respectively, is one of the independent work operations during the shutdown which takes a relatively large proportion of the total shutdown time. The purpose of the present invention is to provide a method of reducing the time of the fuel handling and hence the total shutdown time. SUMMARY OF THE INVENTION The present invention relates to a method and a device which considerably reduce the time of a shutdown where fuel assemblies are lifted out of or into a reactor vessel. According to one aspect of the method according to the invention, the whole of, or parts of, the reactor vessel is/are transported simultaneously from the reactor vessel to the fuel pool located adjacent thereto. The transport takes place in a forced manner by moving groups containing a plurality of fuel assemblies and/or control rods simultaneously between the reactor vessel and the fuel pool. The groups contain fuel assemblies and/or control rods with a mutual order corresponding to the order of the fuel assemblies in the reactor vessel. According to the invention, a gripper is arranged for lifting and/or transport equipment is arranged, for example, in a reactor hall surrounding the reactor vessel. The gripper comprises a number of gripping devices corresponding to the number of fuel assemblies to be lifted out of or into the reactor vessel in a group. Further, the gripper is adapted to transport the removed group of fuel assemblies between the reactor core and the fuel pool. The group may also contain control rods which are lifted out together with the fuel rods. The gripper is thus loaded with a plurality of fuel assemblies and possibly fuel rods in or above the core, whereupon it transports the group of the fuel assemblies and possibly control rods to the fuel pool where these are lowered for temporary storage in a conventional fuel stand. After positioning the removed fuel assemblies in the fuel stand in the fuel pool, the gripper is again moved to a position above the core where it is arranged in a position for lifting out a new group of fuel assemblies and control rods, if any. When it is time to lift the fuel assemblies and the possible control rods in the reactor core, the above method steps are reversed. The advantage of the invention is that a considerable gain in time can be made by lifting a plurality of fuel assemblies and possibly control rods simultaneously out of/into the reactor vessel. The total time for the handling of fuel assemblies and/or control rods can thus be considerably reduced. This saving of time results in a considerable saving of costs.
	claims	1. An ion implanter for compensating for a wafer cut angle, the ion implanter comprising:an orienter adapted to rotate a wafer mounted on an alignment stage thereof to align a notch of the wafer;a wafer stage adapted to have the wafer whose notch has been aligned mounted thereon;an ion implantation angle adjustment unit adapted to adjust an angle of the wafer stage;a cut angle measurement unit adapted to measure the wafer cut angle while the wafer is mounted and rotated on the alignment stage; anda controller adapted to calculate the wafer cut angle and to control the ion implantation angle adjustment unit to compensate for the calculated wafer cut angle. 2. The implanter of claim 1, wherein the cut angle measurement unit includes:a beam generator adapted to generate and irradiate a beam into the wafer; anda detector adapted to receive the beam that is irradiated from the beam generator and reflected from the rotating wafer and to generate a detection signal. 3. The implanter of claim 2, wherein the cut angle measurement unit further includes a beam path adjustment unit adapted to adjust a path of the beam irradiated into the wafer to make the beam inclinedly incident on the wafer. 4. The implanter of claim 2, wherein the controller is adapted to derive, based on the detection signal, a variation of an intensity amount and/or a wavelength of the beam that is caused by rotation of the wafer and to calculate the wafer cut angle based on the variation of the intensity amount and/or the wavelength of the beam. 5. The implanter of claim 4, wherein the controller is adapted to calculate the wafer cut angle using pre-stored data representing a relationship between the wafer cut angle and the variation of the intensity amount and/or the wavelength of the beam. 6. An ion implantation method for compensating for a wafer cut angle, the method comprising:mounting a wafer on a support element;manipulating the support element so as to align a notch of the wafer;calculating the wafer cut angle;adjusting an ion implantation angle of the wafer in consideration of the calculated wafer cut angle; andinjecting an ion beam to implant ions into the wafer. 7. The method of claim 6, wherein the step of calculating the wafer cut angle includes:irradiating a beam into the wafer and receiving the beam that is reflected from the rotating wafer;generating a detection signal based on the received beam;deriving, based on the detection signal, a variation of an intensity amount and/or a wavelength of the beam that is caused by rotation of the wafer; andcalculating the wafer cut angle based on the variation of the intensity amount and/or the wavelength of the beam. 8. The method of claim 7, wherein a path of the beam irradiated into the wafer is adjusted to make the beam inclinedly incident on the wafer. 9. The method of claim 7, wherein the wafer cut angle is calculated using pre-stored data representing a relationship between the wafer cut angle and the variation of the intensity amount and/or the wavelength of the beam.
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	abstract	A method, system, and apparatus for the thermal storage of energy generated by multiple nuclear reactor systems including diverting a first selected portion of energy from a portion of a first nuclear reactor system of a plurality of nuclear reactor systems to at least one auxiliary thermal reservoir, diverting at least one additional selected portion of energy from a portion of at least one additional nuclear reactor system of the plurality of nuclear reactor systems to the at least one auxiliary thermal reservoir, and supplying at least a portion of thermal energy from the auxiliary thermal reservoir to an energy conversion system of a nuclear reactor of the plurality of nuclear reactors.
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	abstract	A system and method of scanning a number of objects such as crates or intermodal containers in a storage area having a plurality of movable racks, each rack occupying at least one level and capable of carrying at least one object. The racks are capable of being moved to establish successive vacant multi-level aisles among the racks. At least one scanner is movable substantially vertically within the successive vacant aisles to scan successive objects substantially adjacent to each vacant aisle to detect at least one pre-determined characteristic.
	abstract	A method and apparatus for providing an alternative cooling system for the suppression pool of a Boiling Water Reactor (BWR) nuclear reactor. The cooling system is operated to cool the suppression pool in the event of a plant accident when normal plant electricity is not available for the conventional residual heat removal system and pumps. The cooling system may also be used to supplement the cooling of the suppression pool via the residual heat removal system. The cooling system is operated and controlled from a remote location, which is ideal during a plant emergency.
050646028	summary	BACKGROUND OF THE INVENTION The present invention relates to energy generation systems and, more particularly, to energy generation systems which rely on a controlled particle flux to sustain the generation process. A major objective of the present invention is to improve the stability and effectiveness of neutron absorption in control rods used to regulate energy generation in a nuclear reactor. Nuclear reactors rely on a controlled, self-perpetuating neutron flux to sustain fission. In a nuclear reactor, neutrons scatter in the uranium-or-plutonium-based fuel rods causing fission. This process generates energy in the form of heat, as well as the additional neutrons needed to keep the reaction self-sustaining. However, since more than one neutron is generated when a uranium or plutonium fission occurs, control rods are used to absorb excess neutrons to keep the reaction in a steady state. Control rods inserted more deeply into the reactor core can absorb enough neutrons to turn the reactor off. Control rod movement is used to control the reactivity ramp rate. There is a control rod position which maintains the power level constant. By controlled withdrawal of the control rod from this position, the power can be ramped up. When the desired power level is reached, the control rod is inserted back into the constant power position. Alternatively, the control rod can be inserted beyond the constant power level position to ramp down the power. The distance of the control rod from the constant power position determines the reactivity ramp rate. Conventionally, control rods include a material that has a high absorption cross-section to the neutrons in the reactor core. In particular, a material with a high cross-section to neutrons having the specific momentum that enables them to cause fission in the fuel rods is employed. To be effective, it must absorb the neutron flux of "fission causing" neutrons. Typical control rods comprise a number of parallel hollow tubes filled with a neutron-absorbing material such as boron carbide, hafnium, cadmium, gadolinium, europium, erbium, samarium, dysprosium, silver and/or indium. Nuclear reactors can be classified according to the method used to transfer fission-generated heat from the reactor core. In boiling-water reactors (BWRs), water is converted to steam as it flows through the core. The steam can be conveyed from the reactor vessel enclosing the core to a turbine. The steam drives the turbine which, in turn, drives a generator to produce electricity. In addition to serving as the source of steam used to drive the turbine, the water serves as a neutron moderator. High-energy, or "fast" neutrons released during a fission reaction are moderated, i.e., slowed, as they scatter off the hydrogen atoms in the water. Neutron moderation is used to facilitate a chain reaction by slowing neutrons to a momentum at which they can be more easily absorbed by fissionable materials in the fuel elements. Likewise, neutron moderation facilitates control of fission since the slowed neutrons are more readily utilized by the Absorber material in the control rods. Some reactors have employed control rods utilizing a "flux-trap" design that takes greater advantage of the neutron moderating effect of water. Flux-trap control rods use hollow rather than solid absorber tubes of neutron-absorbing material. The neutron absorption is most effective at water-absorber boundaries. From the perspective of an individual neutron, the more water-absorber interfaces it encounters, the more likely it will be absorbed. A neutron passing through a solid absorber rod passes from water to absorber at most once. A neutron passing through a hollow tube of absorber material can pass through two water-to-absorber boundaries, and thus has a greater chance of being moderated and consequently absorbed. The additional neutrons absorbed at the interface in the internal part of the tube lead to the term "flux-trap". Typically, the absorption efficiency of a hollow absorber tube is ten to twenty percent higher than it is for a solid absorber rod having the same outer diameter. Since a hollow tube includes less material than a solid rod of the same outer diameter, the flux-trap design provides tubes which require less absorber material. Since absorber materials, notably hafnium, tend to be heavy and expensive, the flux-trap design provides for control rods which are less expensive and more efficient. One problem encountered when employing flux-trap absorber tubes is that their effectiveness decreases with increasing volume of steam in their interiors. The energy the neutrons impart to the absorber tubes is mostly turned into heat, raising their temperature to around 650-700 degrees Fahrenheit. Since the pressure inside the core is close to 1000 pounds per square inch the reactor water will not boil until its temperature is about 550 degrees Fahrenheit. Water flow inside the core is such that the water comes in from the bottom, and flows upwards in a direction parallel to the absorber tubes. The water flowing external to the absorber tubes travels fast enough past the tubes so it does not boil except for an acceptable amount of surface nucleate boiling. However, the water traveling up the inside of the tubes goes slower than the water external to the tubes, and is more susceptible to boiling from the heat generated in the hafnium. If the water boils, the volume of water is displaced by the generated steam. Steam is a less effective moderator than water because it provides fewer scattering targets per unit volume. Neutron moderation and, thus, absorption efficiency decreases with increased steam. While this loss of efficiency is undesirable, of even greater concern are the fluctuations in moderation that can occur, as the amount of steam in the tubes can vary rapidly near the water's boiling point. To alleviate this problem, holes are made in the absorber tube to allow an exchange of water between the inside and outside of the tube. Absorber tubes of this type are described in U.S. Pat. No. 4,882,123. The holes permit relatively cool water from the exterior of the tube to transfer to the interior of the tube so that the tendency to boil is reduced. However, at higher power levels, an undesirable level of interior boiling still occurs. Accordingly, to enhance power control at higher reactor power output levels, flux-trap absorber tubes are desired which more effectively minimize interior boiling. SUMMARY OF THE INVENTION In accordance with the present invention, a nuclear reactor control rod incorporates hollow absorber tubes with flow diverters to urge water into and out of the tube interior through transverse pairs of openings in the tube walls. Each transverse pair of openings includes an inlet and an outlet; the inlet and outlet of each pair are at generally the same height in a vertically extending absorber tube. A flow diverter is disposed between each inlet and its respective outlet, which is typically approximately six inches above the inlet. Each diverter occludes the upward flow path within the interior of the tube and also occludes the transverse flow path between its associated inlet and outlet. Each diverter thus diverts water, or other neutronmoderating fluid, from the tube interior to the tube exterior via its associated outlet. This diversion results in a pressure differential through each of the inlets so that external water is urged into the interior of the tube. Each flow diverter has a dual role as an open gate to the incoming water, and as a closed gate to the water flowing up the tube. Thus, relatively hot internal water is periodically replaced by relatively cool external water. Conveniently, the diverters can be formed by making a series of three-sided cuts on one side of the absorber tube at specified intervals. The cuts define tabs which are then bent inwards to touch the opposite wall on the inside of the tube so as to define a barrier which serves as a flow diverter. Then a hole is made on the opposite side of the tube in the "shade" of each flow diverter. External water is drawn into the tube at the openings where the flow diverters are cut, flows inside the tube until it reaches the spot where the next flow diverter is cut, and is then pushed back outside where it rejoins and is mixed with the cooler external water. Thus the flow diverters have a dual purpose--providing an opening where external water is drawn in and forcing internal water out. Characteristically, the control rod itself has a two-layer construction, with an outside stainless steel sheath surrounding inside absorber tubes. The sheath has holes on each side of the tubes at the intervals where the flow diverters are located. The absorber tubes have the flow diverters which direct the water flow, and inlet and outlet holes in line with the holes in the sheath. The inlet holes in the absorber tube are made automatically when the flow diverters are cut and bent towards the opposite wall inside the absorber tube, although if the hafnium is thick compared with the internal thickness of the tubes, the inlets may be enlarged. The flux-trap control rods of the present invention improve upon prior perforated absorber tubes by increasing the exchange flow between the tube interior and the exterior. This exchange reduces the temperature of the fluid flowing in the hollow of the tube, which in turn, reduces boiling. When boiling is reduced, the volume of water within the tube is more stable, maximizing and stabilizing its neutron moderation capabitilities. This results in more effective and reliable control rods. The incorporation of diverters, as provided by the present invention, thus increases the effectiveness of the flux-trap control rods without requiring major changes in reactor design. The formation of diverters does not require a change in the outer dimensions of the absorber tubes, permitting direct replacement in existing BWRs. These and other features and advantages of the present invention are apparent from the description below, with reference to the following drawings.
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