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	description	This invention relates generally to a medical imaging system, and more particularly, to a method and system for measuring an alignment of a detector of a medical imaging system. A medical imaging system generally includes an illuminating source, a beam collimator and a detector. The detector detects a beam coming from illuminating source through the beam collimator. In case the detector is not aligned with the beam, the medical imaging system produces images of degraded quality and may also lead to extra dosage of radiations to a patient. The detector, therefore, is to be aligned with the illuminating beam. Present techniques provide alignment of the detector as a single unit. However, it is difficult for the present techniques to align field replaceable modules of the detector. Additionally, the present techniques rely on experimentally determined scale factors which are time-consuming and computationally expensive to obtain. Adjustment of the present techniques for more sensitive measurements generally includes using new scaling factors and hence results in additional effort and time. In an exemplary embodiment of the invention, a method for measuring an alignment of a detector is described. The method includes determining, by a processor, the alignment of the detector with respect to a collimated radiation beam. The determination of the alignment is based on a plurality of signals from a first cell of the detector and a second cell of the detector, and is independent of a shape of the collimated radiation beam. In another exemplary embodiment of the invention, a system for measuring an alignment of a detector is described. The system includes a processor configured to determine the alignment of the detector with respect to a collimated radiation beam based on a plurality of signals from a first cell of the detector and a second cell of the detector. The processor is configured to determine the alignment independent of a shape of the collimated radiation beam. Various embodiments of the invention provide a method and a system for measuring an alignment of a detector. In various embodiments of the invention, the detector may be a part of an x-ray imaging system, for example, a Computed Tomography (CT) imaging system. The method is performed by determining by a processor the alignment of the detector based on electrical signals from cells of the detector. FIG. 1 is a block diagram of an x-ray imaging system 100 for measuring an alignment of a detector, in accordance with an embodiment of the invention. X-ray imaging system 100 includes an x-ray source 102, a detector 104 and a processor 106. In an embodiment of the invention, x-ray imaging system 100 further includes a collimator 108 having movable cams 110 and 112. X-ray source 102 produces x-ray beams and projects them towards detector 104. Collimator 108 collimates these x-ray beams and movable cams 110 and 112 of collimator 108 sweep the collimated x-ray beam (also referred to as collimated radiation beam) over detector 104. Detector 104 generates the electrical signals corresponding to the flux of the collimated x-ray beam impinging on a surface of detector 104. The electrical signals generated by detector 104 are received by processor 106. Processor 106 then measures the alignment of the detector based on the electrical signals generated by detector 104. Detector 104 includes a plurality of rows and columns and hence forms a matrix. Each element of the matrix of detector 104 is a detector cell. Each detector cell of detector 104 is configured to generate an electrical signal when a flux of the collimated x-ray beam impinges a surface of the detector cell. Processor 106 may be a computer, a microcontroller, a microcomputer, a programmable logic controller, an application specific integrated circuit, or any other programmable circuit. In an embodiment of the invention, movable cams 110 and 112 of collimator 108 may be tapered. Further, each movable cam 110 and 112 can be independently positioned to alter a position and width of x-ray beams relative to detector 104. Each cam 110 and 112 is positioned by a plurality of motors (not shown). A first one of the motors is coupled via a belt to cam 110 and a second one of the motors is coupled via another belt to cam 112. FIG. 2 is an isometric view of detector 104 when detector 104 is confined to a single plane. Detector 104 includes a plurality of rows 202 and plurality of columns 204 and hence forms a matrix of detector cells 206. A detector cell 208, as shown in FIG. 2, lies on a second row 210 and a second column 212 of detector 104. In an embodiment of the invention, detector 104 includes m rows 202 and n columns 204 of detector cells 206 such that detector 104 has a matrix of m×n detector cells 206. In an exemplary embodiment, m=16 and n=32 such that detector 104 includes 512 detector cells 206. Although detector 104 is illustrated as including sixteen rows 202 (m=16) and thirty-two columns 204 (n=32) of detector cells 206, detector 104 may include any quantity greater than or equal to two rows 202 and any quantity of columns 204. In an embodiment of the invention, detector 104 may also include a plurality of detector modules, where each detector module includes a subset of columns 204. For example, a detector with 16 rows and 32 columns may include two detector modules, each detector module having 16 rows and 16 columns. FIG. 3 is a schematic view of a portion of the x-ray imaging system 100, in accordance with an embodiment of the invention. X-ray source 102 (FIG. 1) is located at a focal spot 302. X-ray imaging system 100 further includes detector 104, a plurality of detector cell rows 312, 314, 316, 318, 320, and 322, and collimator 108 having movable cams 110 and 112. X-rays emanate from focal spot 302 of x-ray source 102 (shown in FIG. 1). The x-rays are collimated by collimator 108 to generate a collimated x-ray beam 303 having edges defined by a penumbra of the collimated x-ray beam 303. In the penumbra, flux of the collimated x-ray beam 303 reduces gradually to zero. Collimated x-ray beam 303 is projected toward detector 104. A portion of collimated x-ray beam 303 forms the penumbra on detector cell rows 320 and 322. Also, a portion of collimated x-ray beam 303 forms an umbra on detector cell rows 312, 314, 316, and 318. In the umbra of collimated x-ray beam 303, the flux of the collimated x-ray beam 303 is a constant. A fan beam plane 328 contains a centerline of focal spot 302 and a centerline 306 of collimated x-ray beam 303 that connects the center of focal spot 302 with the center between the collimator cams 110 and 112. Various embodiments of the invention provide methods for alignment of fan beam plane 328 with a centerline D0 of detector 104. Each detector cell 206 of detector 104 has a gain value and the gain value affects an electrical signal generated by detector cell 206. Each detector cell 206 may have a different gain value than at least one another detector cell 206. When a first detector cell 206 has a different first gain value than a second gain value of at least a second detector cell 206, the gain values of the first and second detector cells 206 are accounted for by dividing the electrical signal from the first detector cell 206 by the first gain value and by dividing the electrical signal from the second detector cell 206 by the second gain value. In an alternative embodiment, each detector cell 206 has the same gain value as any other detector cell 206. The flux of the collimated x-ray beam 303 impinging on the detector cells 206 depends on whether detector cell 206 is under the penumbra or the umbra. The flux of the collimated x-ray beam 303 impinging on the detector cells 206 changes when movable cams 110 and 112 are moved or swept over detector cells 206. In an embodiment of the invention, as movable cams 110 and 112 of collimator 108 come close to each other, detector cells 206 located along detector cell rows 312 and 318, originally under the umbra, gradually shift under the penumbra. Hence, the flux of collimated x-ray beam 303 impinging the surface of detector cells 206 located along detector cell rows 312 and 318 decreases, causing the signals generated by the detector cells to decrease gradually. FIG. 4 is a diagram illustrating detector 104 with two detector modules, in accordance with an embodiment of the invention. Detector 104 includes a first detector module 402 and a second detector module 404. Both detector modules 402 and 404 have a plurality of rows and columns forming a matrix of detector cells 206. In an embodiment of the invention, a first detector cell 406 is located at a top detector row, on A-side, of first detector module 402 and second detector cell 408 is located at a bottom detector row, on B-side of first detector module 402. First detector cell 406 and second detector cell 408 are on the same column of first detector module 402 and equal and oppositely located from a center-line 409 of first detector module 402. Also, a third detector cell 410 is located at a top detector row, on A-side, of second detector module 404 and fourth detector cell 412 is located at a bottom detector row, on B-side of second detector module 404. Third detector cell 410 and fourth detector cell 412 are on the same column of second detector module 404 and equal and oppositely located from a center-line 413 of second detector module 404. Further, first detector module 402 includes detector cell 414 and 416. Detector cells 414 and 416 are located at a top detector row, on A-side, of first detector module 402. Similarly, second detector module 404 includes detector cells 418 and 420. Detector cells 418 and 420 are located at a top detector row, on A-side, of second detector module 404. First detector cell 406 generates a first signal, corresponding to a position of movable cam 110, when the collimated x-ray beam 303 impinges a surface of first detector cell 406. Similarly, third detector cell 410 generates a third signal corresponding to a position of movable cam 110, when the collimated x-ray beam 303 impinges a surface of third detector cell 410. An amplitude or intensity of the first signal generated by first detector cell 406 and the third signal generated by third detector cell 410 decreases when movable cams 110 and 112 sweep over the first and third detector cells 406 and 410. Hence, a first signal curve for first detector cell 406 and a third signal curve for third detector cell 410, including signals generated at different positions of movable cam 110 are obtained. Similarly, a second signal curve for second detector cell 408 and a fourth signal curve for fourth detector cell 412 are obtained when movable cam 112 sweeps over the second detector cell 408 and fourth detector cell 412. FIG. 5 is a graph illustrating the signal curves 506, 514, 516, 510, 518, and 520 generated by six detector cells 406, 414, 416, 410, 418, and 420 of detector 104. Detector cells 406, 414 and 416 are located adjacent to each other on the top detector row, on A-side, of first detector module 402. Also, detector cells 410, 418 and 420 are located on the top detector row, on A-side, of second detector module 404. Signal curves 506, 514, 516, 510, 518, and 520 generated by the detector cells 406, 414, 416, 410, 418, and 420 are plotted against the different positions of movable cam 110. In an embodiment of the invention, the movable cams 110 and 112 are swept toward centerline D0 of detector 104 in successively discrete positions with each position spanning 50 microns from a preceding position. In an alternative embodiment, the movable cams 110 and 112 are swept toward centerline D0 detector 104 in successively continuous positions with each position progressing towards detector 104. Amplitudes of signals generated by detector cells 406, 414, 416, 410, 418 and 420, start decreasing as movable cam 110 sweeps over them. Further, for first detector module 402, the signal curves 506, 514, and 516 generated from signals produced by one of the detector cells 406, 414 and 416 are different because any one of the detector cells 406, 414, and 416 has a different gain value than gain values of the remaining of the detector cells 406, 414, and 416. Similarly, for second detector module 404, the signal curves 510, 518, and 520 generated from signals produced by one of the detector cells 410, 418 and 420 are different because any one of the detector cells 406, 414, and 416 has a different gain value than gain values of the remaining of the detector cells 410, 418, and 420. In an embodiment of the invention, processor 106 normalizes signal curves generated by a plurality of detector cells within a detector module by dividing a value of a signal generated by one the detector cells by a maximum value of a signal generated by one of the detector cells. Normalization is performed on a signal curve, generated by a detector cell, to make the signal curve independent of varying gain values of a plurality of detector cells. FIG. 6 is a graph 600 showing a plurality of normalized signal curves 610 and 620. A Y-axis of the graph 600 shows the normalized detector cell signal values. An X-axis of the graph 600 shows a number of different positions of movable cam 110. Normalized values of signals generated from signals provided by detector cells 406, 414 and 416 overlap each other to generate signal curve 610. Similarly, normalized values of signal curves 510, 518, and 520 generated from signals provided by detector cells 410, 418 and 420 overlap each other to generate signal curve 620. There is a difference in the signals generated by detector cells 406, 414 and 416 of first detector module 402 and detector cells 410, 418 and 420 of second detector module 404, as first detector module 402 and second detector module 404 are not aligned with each other. For example, first detector module 402 is closer to movable cam 110 as compared to second detector module 404. In various embodiments of the invention, processor 106 measures alignment of first detector module 402 and second detector module 404 by determining a difference between a position of movable cam 110 at which the normalized signal curve 610 has a signal amplitude or intensity input via an input device (not shown), such as a keyboard or a mouse, into processor 106 and a position of movable cam 110 at which the normalized signal curve 620 has the same signal intensity. In an embodiment of the invention, positions of movable cam 110 are measured at 0.5 level of maximum signal intensities generated from signals received from detector cells 406, 414, and 416, and of maximum signal intensities from signals received from detector cells 410, 418, and 420. Processor 106 calculates a difference in the positions of movable cam 110 at which the normalized signal curve 610 and the normalized signal curve 620 have the same signal intensity, such as 0.5, to provided a direct distance measurement of misalignment between first detector module 402 and second detector module 404. In yet another embodiment of the invention, a position, x1, of movable cam 110, which sweeps first detector cell 406 and a position, x2, of movable cam 112, which sweeps second detector cell 408, at a pre-specified signal intensity, is determined by processor 106. In an alternative embodiment, the position x1 of movable cam 110 is determined when cam 110 sweeps a detector cell of first detector module 402 that is oppositely located on the other side of center-line 409 from second detector cell 408 but not at the same distance from center-line 409 as that of second detector cell 408. In another alternative embodiment, the position x2 of movable cam 112 is determined when cam 112 sweeps a detector cell of first detector module 402 that is oppositely located on the other side of center-line 409 from first detector cell 406 but not at the same distance from center-line 409 as that of first detector cell 406. A pre-specified signal intensity is input via an input device (not shown), such as a keyboard or a mouse, into processor 106. Positions x1 and x2 are positions from centerline 306 of collimated x-ray beam 303. Both x1 and x2 are positive values as measured from centerline 306 of collimated x-ray beam 303. First detector module 402 is determined to be aligned with collimated x-ray beam 303 if value of equation (1) is zero:(x1−x2)/2 (1)Otherwise, if the value of equation (1) is not zero, equation (1) gives a distance measurement of the misalignment of center-line 409 of first detector module 402 with the centerline 306 of the collimated x-ray beam 303. In one embodiment, equation (1) applies to detector cells 406 and 408, which are located at equal and opposite distances from the centerline D0 of the detector 104. However, in an alternative embodiment, equation (1) is modified to apply to detector cells which are a known, but unequal, distance from the centerline D0 of detector 104. Additionally, the value of equation (1) is independent of a shape of collimated radiation beam 303. Indeed, in various embodiments of this invention, the shape of the collimated radiation beam 303 is continually changed as the collimator cams 110 and 112 are moved. For example, the value of equation (1) does not need to be recalculated when the shape of collimated x-ray beam 303 changes from encompassing 4 rows of detector cells of first detector module 402 to 2 rows of first detector module 402. As another example, the value of equation (1) stays the same before and after changing the shape of collimated x-ray beam from encompassing 2 rows of detector cells of first detector module 402 to 4 rows of first detector module 402. Shape of collimated x-ray beam 303 is not a factor in determining the value of equation (1). In still another embodiment of the invention, positions of movable cams 110 and 112, at a pre-specified signal intensity, on normalized curves generated for a plurality of detector cells, which are located on first detector module 402 and second detector module 404, are used to determined the alignment of detector 104 with respect to the collimated x-ray beam 303. FIG. 7 is a flowchart of a method for measuring the alignment of detector 104, in accordance with an embodiment of the invention. At 702, processor 106 determines alignment of detector 104 based on a plurality of signals from a first and a second detector cell of a detector module of detector 104. A first detector cell and a second detector cell, located along a same column, are at an equal and opposite distance from a center-line of a detector module of detector 104. For example, 406 and 408 may be the first and the second detector cells respectively. FIG. 8 is a flowchart of a method for measuring the alignment of a detector, in accordance with an embodiment of the invention. At 802, collimator 108 having movable cams 110 and 112 is positioned over detector 104. Movable cams 110 and 112 are initially placed so that detector cells 206 are under the umbra. Collimator 108 also collimates x-ray beams 303. At 804, movable cams 110 and 112 sweep the edges of collimated x-ray beam 303 over first detector cell 406 and second detector cell 408. In an alternative embodiment, cams 110 and 112 are initially placed at a position to shield detector cells 406 and 408 from collimated x-ray beam 303, and cams 110 and 112 are sweeped away from center-lines 409 and 413 so that detector cells 406 and 408 pass through the penumbra to perform methods for measuring the alignment of a detector. In yet another alternative embodiment, cam 110 is initially placed at a first position to shield detector cell 406 from collimated x-ray beam 303, cam 112 is initially placed at a second position so that detector cell 408 lies within the umbra, and cams 110 and 112 are sweeped to place cam 110 at a third position within the umbra, to place cam 112 at a fourth position shielding detector cell 408 from collimated x-ray beam 303, and to apply the methods for measuring the alignment of a detector. At 806, first detector cell 406 generates a first signal curve. The first signal curve contains values of signals generated by first detector cell 406 as edges of collimated x-ray beam 303 are swept by movable cam 110 over first detector cell 406. At 808, second detector cell 408 generates a second signal curve. The second signal curve contains values of signals generated by second detector cell 408 as edges of collimated x-ray beam 303 are swept by movable cam 112 over second detector cell 408. At 810, processor 106 determines an alignment of first detector module 402 of detector 104 based on positions of movable cams 110 and 112 at which the first and second signal curves measure the same pre-specified signal intensity. A difference between a position of movable cam 110, corresponding to the pre-specified signal intensity on the first signal curve, and the position of movable cam 112, corresponding to the pre-specified signal intensity on the second signal curve, gives a direct distance measurement of alignment of first detector module 402 of detector 104 with respect to the centerline 306 of collimated x-ray beam 303. Similarly, alignment of second detector module 404 with respect to the centerline 306 of collimated x-ray beam 303 is also determined. It is noted that 802 and 804 are performed by the motors under control of processor 106 and 810 is performed by processor 106. In various embodiments of the invention, direct distance measurement of misalignment at the movable cams level is converted to a distance measurement at the detector level. The direct distance measurement, obtained by calculating a difference, signed average or any other mathematical function, is multiplied by a scaling factor to obtain the measure of alignment at the detector level. The scaling factor may be, for example, but is not limited to, a ratio of the distance between focal spot 302 and collimator 108 and the distance between collimator 108 and detector 104. FIG. 9 and FIG. 10 illustrate a flowchart of a method for measuring the alignment of a detector, in accordance with yet another embodiment of the invention. At 902, collimator 108 having movable cams 110 and 112 is positioned over detector 104. Movable cams 110 and 112 are initially placed so that detector cells 206 are under the umbra. Collimator 108 also collimates the x-rays to generate collimated x-ray beam 303. At 904, movable cams 110 and 112 sweep the edges of collimated x-ray beam 303 over first detector cell 406, second detector cell 408, third detector cell 410, and fourth detector cell 412. At 906, first detector cell 406 generates a first signal curve. The first signal curve contains values of signals generated by first detector cell 406 as an edge of collimated x-ray beam 303 is swept by movable cam 110 over first detector cell 406. At 908, second detector cell 408 generates a second signal curve. The second signal curve contains values of signals generated by second detector cell 408 as an edge of collimated x-ray beam 303 is swept by movable cam 112 over second detector cell 408. At 910, third detector cell 410 generates a third signal curve. The third signal curve contains values of signals generated by third detector cell 410 as an edge of collimated x-ray beam 303 is swept by movable cam 110 over third detector cell 410. At 912, fourth detector cell 412 generates a fourth signal curve. The fourth signal curve contains values of signals generated by fourth detector cell 412 as an edge of collimated x-ray beam 303 is swept by movable cam 112 over fourth detector cell 412. At 914, processor 106 determines a first set of positions of movable cams 110 and 112 at which the first and second signal curves measure same pre-specified signal intensity. In an embodiment of the invention, the first set of positions of movable cams 110 and 112 include a position x1 of movable cam 110 and a position x2 of movable cam 112 with respect to centerline 306. At 916, processor 106 determines a second set of positions of movable cams 110 and 112 at which the third and fourth signal curves measure the same pre-specified signal intensity. In an embodiment of the invention, the second set of positions of movable cams 110 and 112 include a position x3 of movable cam 110 and a position x4 of movable cam 112 with respect to centerline 306. Both x3 and x4 are positive values as measured from centerline 306 of collimated x-ray beam 303. In an alternative embodiment, the position x3 of movable cam 110 is determined when cam 110 sweeps a detector cell of second detector module 404 that is oppositely located on the other side of center-line 413 from fourth detector cell 412 but not at the same distance from center-line 413 as that of fourth detector cell 412. In another alternative embodiment, the position x4 of movable cam 112 is determined when cam 112 sweeps a detector cell of second detector module 404 that is oppositely located on the other side of center-line 413 from third detector cell 410 but not at the same distance from center-line 413 as that of third detector cell 410. At 918, processor 106 determines whether first detector module 402 and second detector module 404 are aligned with each other based on the first and second set of positions. Processor 106 calculates a difference represented by an equation (2){(x1−x2)/2−(x3−x4)/2} (2) Processor calculates the difference represented by equation (2) to determine whether the detector modules 402 and 404 are aligned with respect to each other. If the difference represented by equation (2) is zero, processor 106 determines that the detector modules 402 and 404 are aligned with respect to each other. If the difference represented by equation (2) is not zero, processor 106 determines that the detector modules 402 and 404 are not aligned with respect to each other. It is noted that 902 and 904 are performed by the motors under control of processor 106. It is also noted that 914, 916, and 918 are performed by processor 106. Finally, it is noted that equation (2) is independent of the shape of the collimated radiation beam 303 and, indeed, the profile of the collimated radiation beam 303 is continually changing as the collimator cams 110 and 112 are swept across the detector 104. The value of equation (2) is independent of the shape of collimated x-ray beam 303. For example, the value of equation (2) does not need to be recalculated when the shape of collimated x-ray beam 303 changes from encompassing 6 rows of detector cells of first detector module 402 to 2 rows of detector module 402. As another example, the value of equation (2) stays the same before and after changing the shape of collimated x-ray beam from encompassing 4 rows of detector cells of second detector module 404 to 6 rows of detector module 404. Shape of collimated x-ray beam 303 is not a factor in determining the value of equation (2). Various embodiments of the invention provide a method for measuring an alignment of a detector. The method measures the alignment of a plurality of detector modules of the detector at a module-to-module level. Various embodiments of the invention provide a method for measuring an alignment of a detector. The method directly provides a measure of alignment of a plurality of detector modules, of the detector, in units of distance. Further, the measure of alignment is in the order of microns. Although the various embodiments are described with respect to medical imaging, it should be understood that the various embodiments described herein are not limited to medical applications, but may be utilized in non-medical applications. As used herein, an element or step recited in the singular and preceded with the word “a” or “an” should be understood as not excluding plural elements or steps, unless such exclusion is explicitly recited. Furthermore, references to “an” or “one” “embodiment” of the present invention are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features. The various embodiments of the methods for measuring an alignment of a detector and components thereof may be implemented as part of a computer system. The computer system may include a computer, an input device, a display unit and an interface, for example, for accessing the Internet. As used herein, the term “computer” may include any processor-based or microprocessor-based system including systems using microcontrollers, reduced instruction set circuits (RISC), application specific integrated circuits (ASICs), logic circuits, and any other circuit or processor capable of executing the functions described herein. The above examples are exemplary only, and are thus not intended to limit in any way the definition and/or meaning of the term “computer”. The computer system executes a set of instructions that are stored in one or more storage elements, in order to process input data. The storage elements may also hold data or other information as desired or needed. The storage element may be in the form of an information source or a physical memory element within the processing machine. The set of instructions may include various commands that instruct the processing machine to perform specific operations such as the processes of the various embodiments of the invention. The set of instructions may be in the form of a software program. The software may be in various forms such as system software or application software. Further, the software may be in the form of a collection of separate programs, a program module within a larger program or a portion of a program module. The software also may include modular programming in the form of object-oriented programming. The processing of input data by the processing machine may be in response to user commands, or in response to results of previous processing, or in response to a request made by another processing machine. While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.
	description	This application claims the benefit of provisional U.S. Patent Application No. 60/820,521, filed on Jul. 27, 2006. The disclosure of this provisional patent application is hereby totally incorporated by reference in its entirety. The present invention relates generally to systems and equipment such as systems and equipment used in heating, ventilation, air conditioning, and other systems or machinery of a building or facility. Heating, ventilation and air-conditioning (“HVAC”) systems are used in all types of commercial, industrial and residential facilities (hereinafter referred to as “buildings”). In general, the HVAC system is designed to maintain various predetermined set points, such as temperature. To that end, a system that generates hot air may be controlled on or off depending on the need for heat in a particular location. The supply of conditioned air (hot or cold) may further be controlled by the use of dampers within the air supply system. In larger buildings, the dampers may be actively controlled to regulate the supply of conditioned air. HVAC systems thus include a wide assortment of components which interact with or influence other components. Accordingly, while various parameters on a particular device may be trending out of the normal operating range, the trend may be the result of a problem occurring in another component in the same or even a different system. Thus, while catastrophic failure of a component produces readily identifiable effects, a slowly developing problem is more difficult to identify. Some efforts toward the early identification of potential problems include the monitoring of specific parameters. For example, much can be determined about a chiller's performance (and hence, required maintenance) by monitoring its water and refrigerant conditions and noting any deviation from design or established benchmark values. Basic chiller operating conditions include: Condenser and evaporator pressure and corresponding temperature Waterside temperature drop (ΔT) a Waterside pressure drop (ΔP) Heat exchanger approach temperature Compressor discharge temperature Purge unit run timeFIG. 1 illustrates design values, in I-P (SI) units, for an exemplary single stage R-123 centrifugal liquid chiller operating at full load conditions. The foregoing parameters can be used to identify many problems to which chillers are vulnerable. Many basic chiller problems result in a decreased heat transfer between the refrigerant circuit and the water circuit. In the condenser, or high side, this results in an elevated refrigerant pressure, while in the evaporator, or low side, the result is a lower refrigerant pressure. Increased condensing pressure and/or decreased evaporating pressure results in increased power consumption by the compressor motor and decreased system efficiency. High head pressure (condenser pressure) is a standard safety cutout found on most chillers. Frequent chiller trips (i.e., when the chiller safety cutout is triggered, or “tripped”) can occur if the entering condenser water temperature habitually gets too high. Chiller trips due to hindered heat transfer within the condenser usually occur at less frequent intervals. An example of this is when the condenser water tubes gradually become fouled. On the low side, if the compressor inlet guide vanes are inoperative or out of adjustment, the compressor may not match the evaporator load, causing elevated or lowered evaporator pressure and temperature. The pressure in the evaporator or condenser, which in the exemplary single stage R-123 centrifugal liquid chiller are shell and tube heat exchangers, corresponds to a given temperature. At this temperature and pressure, the refrigerant, in a vapor/liquid state, is changing state as it releases heat to or absorbs heat from the circulating water. These temperature/pressure relationships are generally provided on the manufacturer's refrigerant chart for the particular refrigerant. The operating temperature/pressure may be useful in determining the health of the chiller. While constant monitoring of a system is beneficial, particularly for rapidly escalating situations which have not yet pushed a parameter out of its normal range, merely monitoring the operating conditions do not provide the desired insight into more slowly developing problems. The identification of slowly developing problems is further complicated by the fact that the loading of equipment varies over time. For example, the temperature on a given day may be cool in the early hours of the day. Thus, systems used for cooling may not be operating at all. As the day progresses, however, the outside temperature may rise, driving temperatures in the building upwardly. In response, the cooling system initiates or works harder to maintain the water provided to the various terminals located throughout the building at a constant temperature. Accordingly, the load on a cooling system may vary from zero to one hundred percent loading. As the load on the system changes, of course, the various operating parameters of the system will vary. This normal variance can mask developing problems. In order to correct slowly developing problems before a component failure, it is common for many types of systems and/or equipment to be subjected to maintenance, calibrations and/or alignments at regular intervals. These preventative measures are very effective at early detection and subsequent avoidance of component or system failures. Of course, the procedures may be quite expensive. Moreover, depending upon the nature of the particular system, the capacity of the system may be curtailed or even eliminated during the foregoing activities. These considerations weigh toward a long period of time between the various preventative measures. As the time between the various activities increases, however, the chance of an undesired catastrophic failure also increases. As a consequence, there is a need for apparatus and method that can reduce at least some of the drawbacks and costs identified above. For example, there is a need for a method and/or apparatus that reduces the costs associated with the determination of the health of a device. There is a further need for a method and/or apparatus that can be used to ascertain the health of a device or system that does not place undue constraints on the use of the equipment or system. There is yet a further need for a method and/or apparatus that provides insight into the health of the equipment or system which is not unduly affected by the normal variations in the operating parameters of the equipment or system. The present invention provides for monitoring the health of a system. In one embodiment, a method of monitoring the health of a system includes storing a first plurality of system data associated with at least one steady state capacity level in a memory, obtaining a second plurality of system data indicative of system conditions during system operations, identifying from the second plurality of system data that the system was operating at a steady state capacity level during at least one sample window of the system operations, associating the steady state capacity level of the at least one sample window with the at least one steady state capacity level, retrieving first health data for parameters associated with a first health condition from the first plurality of system data, retrieving second health data for parameters associated with the first health condition from the second plurality of system data that were obtained during the at least one sample window, comparing the first health data with the second health data, determining if the second health data is indicative of a health condition based upon the comparison and displaying the results of the determination. In a further embodiment, a method in accordance with aspects of the invention includes identifying a plurality of parameters associated with a first condition of a device, establishing a plurality of first steady state operating conditions for the device, each of the plurality of steady state operating conditions at a capacity level of the device different from the capacity level of each of the other of the plurality of steady state operating conditions, obtaining first data corresponding to the plurality of parameters during each of the plurality of first steady state operating conditions, storing the first data, obtaining second data corresponding to the plurality of parameters during at least one sample window during a steady state condition during normal operations of the device, identifying the system capacity level during the at least one sample window, associating the at least one sample window with one of the plurality of first steady state operating conditions based upon the identification, comparing, for each of the plurality of parameters, the second data from the at least one sample window with the first data obtained during the associated one of the plurality of first steady state operating conditions, determining the health of the device based upon the comparison and displaying the results of the determination. In another embodiment, a system for monitoring the health of a system includes a plurality of sensors for obtaining a plurality of data associated with at least one health condition of the system, a memory for storing the plurality of data and for storing commands in the memory to store, for each of a plurality of system capacity levels, first steady state data for a plurality of parameters associated with the at least one health condition of the system, obtain normal operations data corresponding to the plurality of parameters during a plurality of sample windows during steady state conditions of the system, associate the normal operations data with the first steady state data based upon a sample window system capacity level for each of the plurality of sample windows, compare, for each of the plurality of parameters, the normal operations data with the associated first steady state data, and display the results of the comparison and a processor for executing the commands. The above described features and advantages, as well as others, will become more readily apparent to those of ordinary skill in the art by reference to the following detailed description and accompanying drawings. FIG. 2 shows an exemplary representative block diagram of a building control system 100 that includes a supervisory control system 102, a system database 104, programmable controllers 108 and 110, and a plurality of configurable controllers 112, 114, 116 and 118. Building control system 100 in this; embodiment is accessible via a network 120 that permits access by a remote browser 122, a laptop computer 124 and/or a wireless device 126. The programmable controllers 108 and 110, which may suitably be an APOGEE® mechanical equipment controller commercially available from Siemens Building Technologies, Inc. of Buffalo Grove, Ill., are operably connected to the supervisory computer 102 through a control system network 128. The control system network 128 may be any communications protocol including Ethernet, TCP/IP, BACnet, or a proprietary protocol. The programmable controllers 108 and 110 are connected to monitoring and control devices which in this embodiment include the configurable controllers 112, 114, 116, and 118, through a low-level data network 130 to provide integrated control, supervision and network management services to the configurable controllers 112, 114, 116, and 118. The supervisory computer 102 in this embodiment includes an INSIGHT® workstation commercially available from Siemens. The supervisory computer 102 may be used for database management, alarm management, and messaging service. The supervisory computer 102 is also used to set up and manage the components in the building control system 100. Each of the configurable controllers 112, 114, 116 and 118 may be configured to provide direct digital control of a variety of mechanical equipment ranging from zone level control of variable air volume (VAV)/constant volume (CV), heat pumps, unit ventilators and fan coil units to air distribution units and mechanical units including spare point pick up of miscellaneous zone equipment. In an exemplary configuration shown in FIG. 3, the configurable controller 112 is configured to control a single zone air handler with a humidifier. The single zone system 132 includes the configurable controller 112, an air supply header 134, a return header 136, an outside air (OA) damper 138, a fan 140, a heater 142, a cooler 144 and a humidifier 146. The single zone system 132 also includes a variety of sensors including a supply header temperature sensor 148, a supply header humidity sensor 150, a zone temperature sensor 152 and a zone humidity sensor 154. The cooler 144 is supplied with chilled water from a chilled water system 158. The chilled water system 158 includes chiller 160 with a condenser 162, an evaporator 164 and a compressor 166. The condenser 162 and the evaporator 164 are shell and tube type heat exchangers. Condenser water is supplied to the condenser 162 through a condenser feed header 168 and returned through a condenser water return header 170. Chilled water is supplied to the cooler 144 and other systems by a chilled water supply header 172 and returned to the evaporator 164 through a chilled water return header 174. The operation of the chilled water system 158 is controlled by the configurable controller 114. To provide the desired control, a variety of sensors are provided in the chilled water system 158. Communications between the various sensors and the controller 114 may be effected in any acceptable mariner such as by providing a wireless network or by wiring the sensors to the controller 114. The sensors in this embodiment include a chilled water supply temperature sensor 176, chilled water return temperature sensor 178, condenser water supply temperature sensor 180, condenser water return temperature sensor 182, chilled water flow sensor 184, refrigerant condensing temperature sensor 186, refrigerant condensing pressure sensor 188, refrigerant liquid temperature sensor 190, refrigerant evaporating pressure sensor 192, amperage or kW consumption sensor 194, compressor discharge temperature sensor 196, chilled water differential pressure sensor 198, condenser water differential pressure sensor 200, oil temperature sensor 202, oil pressure sensor 204, condenser water flow sensor 206, outside air dry bulb temperature sensor 208, outside air dew point temperature sensor 210 and a purge unit run time sensor (not shown). Exemplary sensor ranges and accuracies for the foregoing sensors are provided in FIG. 5. The sensors associated with the chilled water system 158 are typically used to monitor the chilled water system 158 during operations so as to identify any components that are not operating properly. The data available from the sensors associated with the chilled water system 158 are further used by a health monitoring program 214 which in this embodiment is stored within the system database 104. As depicted in FIG. 6, the health monitoring program 214 includes sub modules 216, 218, 220, 222, 224, 226, 228, 230 and 232. The health monitoring program 214 includes instructions which are common to the sub modules. In one embodiment, the health monitoring program includes the following commands: 00100 C00200 C DEFINING CHILLER NAMING CONVENSION00300 DEFINE (X, “CHILLER-1”)00400 C DEFINING DEM NAMING CONVENSION00500 DEFINE (Y, “CHL01.DEM1”)00600 C DETERMINING IF THE CHILLER IS RUNNING00700 IF(“%X%:OPER CODE” .GE. 8.0 .AND.“%X%:OPER CODE” .LE. 9.0)THEN ON(″%X%00800 C WAIT FOR STARTED CHILLER TO SETTLE OUT00900 IF(“%X%.STATUS” .NE. ON) THEN OFF(“%X%.STARTED”)01000 WAIT(180,“%X%.STATUS”,“%X%.STARTED”,11)01100 C CALCULATE COMPRESSOR MOTOR CURRENT01200 “%X%.CURRENT” = “%Y%:CURRENT”01300 C CALCULATE COMPRESSOR DISCHARGETEMPERATURE01400 “%X%.CDT” = “%X%:COMPDISCH T”01500 C CALCULATE PURGE PRESSURE01600 “%X%.PURGE” = “%X%:PURGE PRESS”01700 C CALCULATE CONDENSER WATER DELTATEMPERATURE01800 “%X%.CWDT” = “%X%:LCNDW TEMP” − “%X%:RCNDWTEMP”01900 C CALCULATE CONDENSER WATER DELTAPRESSURE02000 “%X%.CWDP” = “%X%.CWDP”02100 C CALCULATE CONDENSER APPROACH02200 “%X%.CDAP” = “%X%:CONDSAT TEMP” − “%X%:LCNDWTEMP”02300 C CALCULATE CONDENSER REFRIGERANT PRESSURE02400 “%X%.CDRP” = “%X%:COND PRESS”02500 C CALCULATE CONDENSER REFRIGERANT SATURATIONTEMP02600 “%X%.CDRST” = “%X%:CONDSAT TEMP”02700 C DESIGN COND. WATER DELTA TEMP 5%TOLERANCES @ 30% LOA02800 “%X%.D30.CWDT.HI” = “%X%.D30.CWDT” * 1.0502900 “%X%.D30.CWDT.LO” = “%X%.D30.CWDT” * 0.9503000 C DESIGN COND WATER DELTA TEMP 5%TOLERANCES @ 40% LOA03100 “%X%.D40.CWDT.HI” = “%X%.D40.CWDT” * 1.0503200 “%X%.D40.CWDT.LO” = “%X%.D40.CWDT” * 0.9503300 C DESIGN COND WATER DELTA TEMP 5%TOLERANCES @ 50% LOA03400 “%X%.D50.CWDT.HI” = “%X%.D50.CWDT” * 1.0503500 “%X%.D50.CWDT.LO” = “%X%.D50.CWDT” * 0.9503600 C DESIGN COND WATER DELTA TEMP 5%TOLERANCES @ 60% LOA03700 “%X%.D60.CWDT.HI” = “%X%.D60.CWDT” * 1.0503800 “%X%.D60.CWDT.LO” = “%X%.D60.CWDT” * 0.9503900 C DESIGN COND WATER DELTA TEMP 5%TOLERANCES @ 70% LOA04000 “%X%.D70.CWDT.HI” = “%X%.D70.CWDT” * 1.0504100 “%X%.D70.CWDT.LO” = “%X%.D70.CWDT” * 0.9504200 C DESIGN COND WATER DELTA TEMP 5%TOLERANCES @ 80% LOA04300 “%X%.D80.CWDT.HI” = “%X%.D80.CWDT” * 1.0504400 “%X%.D80.CWDT.LO” = “%X%.D80.CWDT” * 0.9504500 C DESIGN COND WATER DELTA TEMP 5%TOLERANCES @ 90% LOA04600 “%X%.D90.CWDT.HI” = “%X%.D90.CWDT” * 1.0504700 “%X%.D90.CWDT.LO” = “%X%.D90.CWDT” * 0.9504800 C DESIGN COND WATER DELTA TEMP 5%TOLERANCES @ 100% LO04900 “%X%.D100.CWDT.HI” = “%X%.D100.CWDT” * 1.0505000 “%X%.D100.CWDT.LO” = “%X%.D100.CWDT” * 0.9505100 C DESIGN COND WATER DELTA PRES 5%TOLERANCES @ 30% LOAD05200 “%X%.D30.CWDP.HI” = “%X%.D30.CWDP” * 1.0505300 “%X%.D30.CWDP.LO” = “%X%.D30.CWDP” * 0.9505400 C DESIGN COND WATER DELTA PRES 5%TOLERANCES @ 40% LOAD05500 “%X%.D40.CWDP.HI” = “%X%.D40.CWDP” * 1.0505600 “%X%.D40.CWDP.LO” = “%X%.D40.CWDP” * 0.9505700 C DESIGN COND WATER DELTA PRES 5%TOLERANCES @ 50% LOAD05800 “%X%.D50.CWDP.HI” = “%X%.D50.CWDP” * 1.0505900 “%X%.D50.CWDP.LO” = “%X%.D50.CWDP” * 0.9506000 C DESIGN COND WATER DELTA PRES 5%TOLERANCES @ 60% LOAD6100 “%X%.D60.CWDP.HI” = “%X%.D60.CWDP” * 1.0506200 “%X%.D60.CWDP.LO” = “%X%.D60.CWDP” * 0.9506300 C DESIGN COND WATER DELTA PRES 5%TOLERANCES @ 70% LOAD06400 “%X%.D70.CWDP.HI” = “%X%.D70.CWDP” * 1.0506500 “%X%.D70.CWDP.LO” = “%X%.D70.CWDP” * 0.9506600 C DESIGN COND WATER DELTA PRES 5%TOLERANCES @ 80% LOAD06700 “%X%.D80.CWDP.HI” = “%X%.D80.CWDP” * 1.0506800 “%X%.D80.CWDP.LO” = “%X%.D80.CWDP” * 0.9506900 C DESIGN COND WATER DELTA PRES 5%TOLERANCES @ 90% LOAD07000 “%X%.D90.CWDP.HI” = “%X%.D90.CWDP” * 1.0507100 “%X%.D90.CWDP.LO” = “%X%.D90.CWDP” * 0.9507200 C DESIGN COND WATER DELTA PRES5%TOLERANCES @ 100% LOAD07300 “%X%.D100.CWDP.HI” = “%X%.D100.CWDP” * 1.0507400 “%X%.D100.CWDP.LO” = “%X%.D100.CWDP” * 0.9507500 C DESIGN COND APPROACH 5% TOLERANCES @ 30%LOAD07600 “%X%.D30.CDAP.HI” = “%X%.D30.CDAP” * 1.0507700 “%X%.D30.CDAP.LO” = “%X%.D30.CDAP” * 0.9507800 C DESIGN CONDENSER APPROACH 5%TOLERANCES @ 40% LOAD07900 “%X%.D40.CDAP.HI” = “%X%.D40.CDAP” * 1.0508000 “%X%.D40.CDAP.LO” = “%X%.D40.CDAP” * 0.9508100 C DESIGN CONDENSER APPROACH 5%TOLERANCES @ 50% LOAD08200 “%X%.D50.CDAP.HI” = “%X%.D50.CDAP” * 1.0508300 “%X%.D50.CDAP.LO” = “%X%.D50.CDAP” * 0.9508400 C DESIGN CONDENSER APPROACH 5%TOLERANCES @ 60% LOAD08500 “%X%.D60.CDAP.HI” = “%X%.D60.CDAP” * 1.0508600 “%X%.D60.CDAP.LO” = “%X%.D60.CDAP” * 0.9508700 C DESIGN CONDENSER APPROACH 5%TOLERANCES @ 70% LOAD08800 “%X%.D70.CDAP.HI” = “%X%.D70.CDAP” * 1.0508900 “%X%.D70.CDAP.LO” = “%X%.D70.CDAP” * 0.9509000 C DESIGN CONDENSER APPROACH 5%TOLERANCES @ 80% LOAD09100 “%X%.D80.CDAP.HI” = “%X%.D80.CDAP” * 1.0509200 “%X%.D80.CDAP.LO” = “%X%.D80.CDAP” * 0.9509300 C DESIGN CONDENSER APPROACH 5%TOLERANCES @ 90% LOAD09400 “%X%.D90.CDAP.HI” = “%X%.D90.CDAP” * 1.0509500 “%X%.D90.CDAP.LO” = “%X%.D90.CDAP” * 0.9509600 C DESIGN CONDENSER APPROACH 5%TOLERANCES @ 100% LOAD09700 “%X%.D100.CDAP.HI” = “%X%.D100.CDAP” * 1.0509800 “%X%.D100.CDAP.LO” = “%X%.D100.CDAP” * 0.9509900 C CALCULATE CHILLED WATER DELTATEMPERATURE10000 “%X%.CHWDT” =“%X%:RCHW TEMP” − “%X%:LCHW TEMP”10100 C CALCULATE CHILLED WATER DELTA PRESSURE10200 “%X%.CHWDP” = “%X%.CHWDP”10300 C CALCULATE EVAPORATOR APPROACH10400 “%X%.EVAP” =“%X%:LCHW TEMP” − “%X%:EVAPSAT TEMP”10500 C CALCULATE EVAPORATOR REFRIGERANTPRESSURE10600 “%X%.EVRP” = “%X%:EVAP PRESS”10700 C CALC EVAPORATOR REFRIGERANT SATURATIONTEMPERATURE10800 “%X%.EVRST” = “%X%:EVAPSAT TEMP”10900 C DESIGN CHILL WATER DELTA PRES 5%TOLERANCES @ 30% LOAD11000 “%X%.D30.CHWDP.HI” = “%X%.D30.CHWDP” * 1.0511100 “%X%.D30.CHWDP.LO” = “%X%.D30.CHWDP” * 0.9511200 C DESIGN CHILL WATER DELTA PRES 5%TOLERANCES @ 40% LOAD11300 “%X%.D40.CHWDP.HI” = “%X%.D40.CHWDP” * 1.0511400 “%X%.D40.CHWDP.LO” = “%X%.D40.CHWDP” * 0.9511500 C DESIGN CHILL WATER DELTA PRES 5%TOLERANCES @ 50% LOAD11600 “%X%.D50.CHWDP.HI” = “%X%.D50.CHWDP” * 1.0511700 “%X%.D50.CHWDP.LO” = “%X%.D50.CHWDP” * 0.9511800 C DESIGN CHILL WATER DELTA PRES 5%TOLERANCES @ 60% LOAD11900 “%X%.D60.CHWDP.HI” = “%X%.D60.CHWDP” * 1.0512000 “%X%.D60.CHWDP.LO” = “%X%.D60.CHWDP” * 0.9512100 C DESIGN CHILL WATER DELTA PRES 5%TOLERANCES @ 70% LOAD12200 “%X%.D70.CHWDP.HI” = “%X%.D70.CHWDP” * 1.0512300 “%X%.D70.CHWDP.LO” = “%X%.D70.CHWDP” * 0.9512400 C DESIGN CHILL WATER DELTA PRES 5%TOLERANCES @ 80% LOAD12500 “%X%.D80.CHWDP.HI” = “%X%.D80.CHWDP” * 1.0512600 “%X%.D80.CHWDP.LO” = “%X%.D80.CHWDP” * 0.9512700 C DESIGN CHILL WATER DELTA PRES 5%TOLERANCES @ 90% LOAD12800 “%X%.D90.CHWDP.HI” = “%X%.D90.CHWDP” * 1.0512900 “%X%.D90.CHWDP.LO” = “%X%.D90.CHWDP” * 0.9513000 C DESIGN CHILL WATER DELTA PRES 5%TOLERANCES @ 100% LOAD13100 “%X%.D100.CHWDP.HI” = “%X%.D100.CHWDP” * 1.0513200 “%X%.D100.CHWDP.LO” = “%X%.D100.CHWDP” * 0.9513300 C CALCULATE TEMPERATURE ADJUSTED MAXIMUMCAPACITY13400 “%X%.CAPFT” = −(1.74204) +0.029292 * “%X%:LCHW TEMP” − 0.000067 * “%X%:13500 “%X%.ADJCAP” = “%X%.MAXCAP” * “%X%.CAPFT”13600 C CALCULATE CURRENT LOAD13700 “%X%.CURLOAD” =“%X%.CHWFLOW” * “%X%.CHWDT” / 2413800 C CALCULATE PART LOAD13900 “%X%.PLOAD” = “%X%.CURLOAD” / “%X%.ADJCAP” * 10014000 C CALCULATE CHILLER EFFICIENCY (KW/TON)14100 “%X%.EFF” = “%Y%:DEMAND” / “%X%.CURLOAD”14200 C CALCULATE CHILLER COEFFICIENT OFPERFORMANCE14300 “%X%.COP” = 3.516 / “%X%.EFF”14400 GOTO 100 Each of the sub modules 216, 218, 220, 222, 224, 226, 228, 230 and 232 include instructions for assessing the health of the chilled water system 158 with respect to a particular condition. This is accomplished by analysis of various groups of parameters which are affected by the particular condition. Specifically, the sub module 216 is configured to provide data which may be used to determine if chilled water is bypassing the chilled water tubes within the condenser 162. This condition can occur when a leak develops between the chilled water return header 174 and the chilled water supply header 172. More precisely, a division plate (not shown) is used to separate the chilled water return header 174 and the chilled water supply header 172 within the shell of the condenser 162. Thus, a leak in the division plate (not shown) will allow water to bypass the water tubes in a heat exchanger and mix with the chilled water that has been cooled by the condenser 162. More common is for a division plate gasket to be ruptured or missing. In the event such a condition develops, then, for a given partial load level, the chill water differential temperature, the chill water differential pressure, the evaporator refrigerant pressure and the evaporator refrigerant saturation temperature will be less than the design values for the particular partial load. Additionally, the evaporator approach will be higher than the design value for the particular partial load. In one embodiment, the sub module 216 includes the following commands: 00100 C DEFINE CHILLER NAMING CONVENSION00200 DEFINE (X, “MHS.CHL1”)00300 C DEFINES THE % LOAD DESIGN CRITERIA VALUECOMPARISON00400 IF(“%X%.PLOAD” .GT. 25.0 .AND. “%X%.PLOAD” .LE. 35.0)THEN GOSUB 1400 ″%00500 IF(“%X%.PLOAD” .GT. 35.0 .AND. “%X%.PLOAD” .LE. 45.0)THEN GOSUB 1400 ″%00600 IF(“%X%.PLOAD” .GT. 45.0 .AND. “%X%.PLOAD” .LE. 55.0)THEN GOSUB 1400 ″%00700 IF(“%X%.PLOAD” .GT. 55.0 .AND. “%X%.PLOAD” .LE. 65.0)THEN GOSUB 1400 ″%00800 IF(“%X%.PLOAD” .GT. 65.0 .AND. “%X%.PLOAD” .LE. 75.0)THEN GOSUB 1400 ″%00900 IF(“%X%.PLOAD” .GT. 75.0 .AND. “%X%.PLOAD” .LE. 85.0)THEN GOSUB 1400 ″%01000 IF(“%X%.PLOAD” .GT. 85.0 .AND. “%X%.PLOAD” .LE. 95.0)THEN GOSUB 1400 ″%01100 IF(“%X%.PLOAD” .GT. 95.0) THEN GOSUB 1400 “%X%.D100.CHWDT”,″%X%.D100.CHW01200 GOTO 320001300 C SUBROUTINE FOR CONDITIONS WHICH POINT TOHAVING WATER BYPASSING01400 $LOC1 = 001500 IF(“%X%.CHWDT” .LT. $ARG1) THEN $LOC1 = $LOC1 + 101600 IF(“%X%.CHWDP” .LT. $ARG2) THEN $LOC1 = $LOC1 + 101700 IF(“%X%.EVAP” .GT. $ARG3) THEN $LOC1 = $LOC1 + 101800 IF(“%X%.EVRP” .LT. $ARG4) THEN $LOC1 = $LOC1 + 101900 IF(“%X%.EVRST” .LT. $ARG5) THEN $LOC1 = $LOC1 + 102000 C DETERMINES THE NUMBER OF FLAGS02100 IF(“%X%.STARTED” .EQ. OFF .OR. $LOC1 .NE. 5) THENGOTO 240002200 IF($LOC1 .EQ. 5 .AND. SECNDS .LE. 300) THEN GOTO 260002300 “%X%.EVAP.TUBE.BYPASS.FLAGS” =“%X%.EVAP.TUBE.BYPASS.FLAGS” + 102400 SECNDS = 002500 C DETERMINES TOTAL NUMBER OF SAMPLES02600 IF(“%X%.STARTED” .EQ. OFF) THEN GOTO 290002700 IF(“%X%.STARTED” .EQ. ON .AND. SECND1 .LE. 300) THENGOTO 300002800 “%X%.EVAP.TUBE.BYPASS.SAMPLES” = “%X%.EVAP.TUBE.BYPASS.SAMPLES” + 102900 SECND1 = 003000 RETURN03100 C CALCULATES THE DAILY PERCENTAGE OF DATAWHICH MET THE CRITERIA03200 IF(TIME .NE. 23:59) THEN GOTO 370003300 IF(“%X%.EVAP.TUBE.BYPASS.SAMPLES” .NE. 0) THENGOTO 360003400 “%X%.EVAP.TUBE.BYPASS” = 003500 GOTO 370003600 “%X%.EVAP.TUBE.BYPASS” = “%X%.EVAP.TUBE.BYPASS.FLAGS” /“%X%.EVAP.TUBE.B03700 IF(TIME .NE. 00:00) THEN GOTO 420003800 SECNDS = 003900 SECND1 = 004000 “%X%.EVAP.TUBE.BYPASS.FLAGS” = 004100 “%X%.EVAP.TUBE.BYPASS.SAMPLES” = 004200 C END OF PROGRAM04300 GOTO 100 The sub module 218 is configured to provide data which may be used to determine if condenser water is bypassing the condenser water tubes within the evaporator 164. This condition can occur when a leak develops between the condenser feed header 168 and the condenser water return header 170 in a manner similar to the leak discussed above between the chilled water return header 174 and the chilled water supply header 172 within the shell of the condenser 162. In the event such a condition develops, then, for a given partial load level, the condenser water differential temperature and the condenser water differential pressure will be lower than the design values for the particular partial load. Additionally, the condenser approach, the condenser refrigerant pressure, and the condenser refrigerant saturation temperature will be higher than the design values for the particular partial load. In one embodiment, the sub module 218 includes the following commands: 00100 C DEFINE CHILLER NAMING CONVENSION00200 DEFINE (X, “MHS.CHL1”)00300 C DEFINES THE % LOAD DESIGN CRITERIA VALUECOMPARISON00400 IF(“%X%.PLOAD” .GT. 25.0 .AND. “%X%.PLOAD” .LE. 35.0)THEN GOSUB 1400 ″%00500 IF(“%X%.PLOAD” .GT. 35.0 .AND. “%X%.PLOAD” .LE. 45.0)THEN GOSUB 1400 ″%00600 IF(“%X%.PLOAD” .GT. 45.0 .AND. “%X%.PLOAD” .LE. 55.0)THEN GOSUB 1400 ″%00700 IF(“%X%.PLOAD” .GT. 55.0 .AND. “%X%.PLOAD” .LE. 65.0)THEN GOSUB 1400 ″%00800 IF(“%X%.PLOAD” .GT. 65.0 .AND. “%X%.PLOAD” .LE. 75.0)THEN GOSUB 1400 ″%00900 IF(“%X%.PLOAD” .GT. 75.0 .AND. “%X%.PLOAD” .LE. 85.0)THEN GOSUB 1400 ″%01000 IF(“%X%.PLOAD” .GT. 85.0 .AND. “%X%.PLOAD” .LE. 95.0)THEN GOSUB 1400 ″%01100 IF(“%X%.PLOAD” .GT. 95.0) THEN GOSUB 1400 “%X%.D100.CWDT”,″%X%.D100.CWDP01200 GOTO 320001300 C SUBROUTINE FOR CONDITIONS WHICH POINT TO HAVING WATER BYPASSING01400 $LOC1 = 001500 IF(“%X%.CWDT” .LT. $ARG1) THEN $LOC1 = $LOC1 + 101600 IF(“%X%.CWDP” .LT. $ARG2) THEN $LOC1 = $LOC1 + 101700 IF(“%X%.CDAP” .GT. $ARG3) THEN $LOC1 = $LOC1 + 101800 IF(“%X%.CDRP” .GT. $ARG4) THEN $LOC1 = $LOC1 + 101900 IF(“%X%.CDRST” .GT. $ARG5) THEN $LOC1 = $LOC1 + 102000 C DETERMINES THE NUMBER OF FLAGS02100 IF(“%X%.STARTED” .EQ. OFF .OR. $LOC1 .NE. 5) THENGOTO 240002200 IF($LOC1 .EQ. 5 .AND. SECNDS .LE. 300) THEN GOTO 260002300 “%X%.COND.TUBE.BYPASS.FLAGS” = “%X%.COND.TUBE.BYPASS.FLAGS” + 102400 SECNDS = 002500 C DETERMINES TOTAL NUMBER OF SAMPLES02600 IF(“%X%.STARTED” .EQ. OFF) THEN GOTO 290002700 IF(“%X%.STARTED” .EQ. ON .AND. SECND1 .LE. 300) THENGOTO 300002800 “%X%.COND.TUBE.BYPASS.SAMPLES” = “%X%.COND.TUBE.BYPASS.SAMPLES” + 102900 SECND1 = 003000 RETURN03100 C CALCULATES THE DAILY PERCENTAGE OF DATAWHICH MET THE CRITERIA03200 IF(TIME .NE. 23:59) THEN GOTO 370003300 IF(“%X%.COND.TUBE.BYPASS.SAMPLES” .NE. 0) THENGOTO 360003400 “%X%.COND.TUBE.BYPASS” = 003500 GOTO 370003600 “%X%.COND.TUBE.BYPASS” =“%X%.COND.TUBE.BYPASS.FLAGS”/ “%X%.COND.TUBE.B03700 IF(TIME .NE. 00:00) THEN GOTO 420003800 SECNDS = 003900 SECND1 = 004000 “%X%.COND.TUBE.BYPASS.FLAGS” = 004100 “%X%.COND.TUBE.BYPASS.SAMPLES” = 004200 C END OF PROGRAM04300 GOTO 100 The sub module 220 is configured to provide data which may be used to determine the health of the chilled water flow rate. Reduced flow may occur as a result of dirty or plugged strainers, closed valves, improperly sized piping, improperly adjusted flow control, plugged tubes or improperly performing pumps. Air in the condenser water circuit will also cause a low water flow rate. In the event such a condition develops, then, for a given partial load level, the chilled water differential pressure, the evaporator refrigerant pressure, and the evaporator refrigerant saturation temperature will be lower than the design values for the particular partial load. Additionally, the chilled water differential temperature and the evaporator approach will be higher than the design value for the particular partial load. In one embodiment, the sub module 220 includes the following commands: 00100 C DEFINE CHILLER NAMING CONVENSION00200 DEFINE (X, “MHS.CHL1”)00300 C DEFINES THE % LOAD DESIGN CRITERIA VALUECOMPARISON00400 IF(“%X%.PLOAD” .GT. 25.0 .AND. “%X%.PLOAD” .LE. 35.0) THEN GOSUB 1400 ″%00500 IF(“%X%.PLOAD” .GT. 35.0 .AND. “%X%.PLOAD” .LE. 45.0) THEN GOSUB 1400 ″%00600 IF(“%X%.PLOAD” .GT. 45.0 .AND. “%X%.PLOAD” .LE. 55.0) THEN GOSUB 1400 ″%00700 IF(“%X%.PLOAD” .GT. 55.0 .AND. “%X%.PLOAD” .LE. 65.0) THEN GOSUB 1400 ″%00800 IF(“%X%.PLOAD” .GT. 65.0 .AND. “%X%.PLOAD” .LE. 75.0) THEN GOSUB 1400 ″%00900 IF(“%X%.PLOAD” .GT. 75.0 .AND. “%X%.PLOAD” .LE. 85.0) THEN GOSUB 1400 ″%01000 IF(“%X%.PLOAD” .GT. 85.0 .AND. “%X%.PLOAD” .LE. 95.0) THEN GOSUB 1400 ″%01100 IF(“%X%.PLOAD” .GT. 95.0) THEN GOSUB 1400 “%X%.D100.CHWDT”,“%X%.D100.CHW01200 GOTO 320001300 C SUBROUTINE FOR CONDITIONS WHICH POINT TO LOW CHILLED WATER FLOW01400 $LOC1 = 001500 IF(“%X%.CHWDT” .GT. $ARG1) THEN $LOC1 = $LOC1 + 101600 IF(“%X%.CHWDP” .LT. $ARG2) THEN $LOC1 = $LOC1 + 101700 IF(“%X%.EVAP” .GT. $ARG3) THEN $LOC1 = $LOC1 + 101800 IF(“%X%.EVRP” .LT. $ARG4) THEN $LOC1 = $LOC1 + 101900 IF(“%X%.EVRST” .LT. $ARG5) THEN $LOC1 = $LOC1 + 102000 C DETERMINES THE NUMBER OF FLAGS02100 IF(“%X%.STARTED” .EQ. OFF .OR. $LOC1 .NE. 5) THENGOTO 240002200 IF($LOC1 .EQ. 5 .AND. SECNDS .LE. 300) THEN GOTO 260002300 “%X%.LO.CHW.FLOW.FLAGS” = “%X%.LO.CHW.FLOW.FLAGS” + 1 02400 SECNDS = 002500 C DETERMINES TOTAL NUMBER OF SAMPLES02600 IF(“%X%.STARTED” .EQ. OFF) THEN GOTO 290002700 IF(“%X%.STARTED” .EQ. ON .AND. SECND1 .LE. 300) THENGOTO 300002800 “%X%.LO.CHW.FLOW.SAMPLES” = “%X%.LO.CHW.FLOW.SAMPLES” + 102900 SECND1 = 003000 RETURN03100 C CALCULATES THE DAILY PERCENTAGE OF DATAWHICH MET THE CRITERIA03200 IF(TIME .NE. 23:59) THEN GOTO 370003300 IF(“%X%.LO.CHW.FLOW.SAMPLES” .NE. 0) THEN GOTO360003400 “%X%.LO.CHW.FLOW” = 003500 GOTO 370003600 “%X%.LO.CHW.FLOW” = “%X%.LO.CHW.FLOW.FLAGS” / “%X%.LO.CHW.FLOW.SAMPLES”03700 IF(TIME .NE. 00:00) THEN GOTO 420003800 SECNDS = 003900 SECND1 = 004000 “%X%.LO.CHW.FLOW.FLAGS” = 004100 “%X%.LO.CHW.FLOW.SAMPLES” = 004200 C END OF PROGRAM04300 GOTO 100 The sub module 222 is configured to provide data which may be used to determine the health of the condenser water flow rate. Reduced flow may occur as a result of dirty or plugged strainers, closed valves, improperly sized piping, improperly adjusted flow control, plugged tubes, or improperly performing pumps. Air in the condenser water circuit will also cause a low water flow rate. In the event such a condition develops, then, for a given partial load level, the condenser water differential pressure will be lower than the design values for the particular partial load. Additionally, the condenser water differential temperature, condenser approach, condenser refrigerant pressure, and condenser refrigerant saturation temperature will be higher than the design value for the particular partial load. In one embodiment, the sub module 222 includes the following commands: 0100 C DEFINE CHILLER NAMING CONVENSION00200 DEFINE (X, “MHS.CHL1”)00300 C DEFINES THE % LOAD DESIGN CRITERIA VALUECOMPARISON00400 IF(“%X%.PLOAD” .GT. 25.0 .AND. “%X%.PLOAD” .LE. 35.0) THEN GOSUB 1400 ″%00500 IF(“%X%.PLOAD” .GT. 35.0 .AND. “%X%.PLOAD” .LE. 45.0) THEN GOSUB 1400 ″%00600 IF(“%X%.PLOAD” .GT. 45.0 .AND. “%X%.PLOAD” .LE. 55.0) THEN GOSUB 1400 ″%00700 IF(“%X%.PLOAD” .GT. 55.0 .AND. “%X%.PLOAD” .LE. 65.0) THEN GOSUB 1400 ″%00800 IF(“%X%.PLOAD” .GT. 56.0 .AND. “%X%.PLOAD” .LE. 75.0) THEN GOSUB 1400 ″%00900 IF(“%X%.PLOAD” .GT. 75.0 .AND. “%X%.PLOAD” .LE. 85.0) THEN GOSUB 1400 ″%01000 IF(“%X%.PLOAD” .GT. 85.0 .AND. “%X%.PLOAD” .LE. 95.0) THEN GOSUB 1400 ″%01100 IF(“%X%.PLOAD” .GT. 95.0) THEN GOSUB 1400 “%X%.D100.CWDT”,″%X%.D100.CWDP01200 GOTO 320001300 C SUBROUTINE FOR CONDITIONS WHICH POINT TO LOW CONDENSER WATER FLO01400 $LOC1 = 001500 IF(“%X%.CWDT” .GT. $ARG1) THEN $LOC1 = $LOC1 + 101600 IF(“%X%.CWDP” .LT. $ARG2) THEN $LOC1 = $LOC1 + 101700 IF(“%X%.CDAP” .GT. $ARG3) THEN $LOC1 = $LOC1 + 101800 IF(“%X%.CDRP” .GT. $ARG4) THEN $LOC1 = $LOC1 + 101900 IF(“%X%.CDRST” .GT. $ARG5) THEN $LOC1 = $LOC1 + 102000 C DETERMINES THE NUMBER OF FLAGS02100 IF(“%X%.STARTED” .EQ. OFF .OR. $LOC1 .NE. 5) THENGOTO 240002200 IF($LOC1 .EQ. 5 .AND. SECNDS .LE. 300) THEN GOTO 260002300 “%X%.LO.CW.FLOW.FLAGS” =“%X%.LO.CW.FLOW.FLAGS” + 102400 SECNDS = 002500 C DETERMINES TOTAL NUMBER OF SAMPLES02600 IF(“%X%.STARTED” .EQ. OFF) THEN GOTO 290002700 IF(“%X%.STARTED” .EQ. ON .AND. SECND1 .LE. 300) THENGOTO 300002800 “%X%.LO.CW.FLOW.SAMPLES” =“%X%.LO.CW.FLOW.SAMPLES” + 102900 SECND1 = 003000 RETURN03100 C CALCULATES THE DAILY PERCENTAGE OF DATAWHICH MET THE CRITERIA03200 IF(TIME .NE. 23:59) THEN GOTO 370003300 IF(“%X%.LO.CW.FLOW.SAMPLES” .NE. 0) THEN GOTO 360003400 “%X%.LO.CW.FLOW” = 003500 GOTO 370003600 “%X%.LO.CW.FLOW” = “%X%.LO.CW.FLOW.FLAGS” / “%X%.LO.CW.FLOW.SAMPLES” * 103700 IF(TIME .NE. 00:00) THEN GOTO 420003800 SECNDS = 003900 SECND1 = 004000 “%X%.LO.CW.FLOW.FLAGS” = 004100 “%X%.LO.CW.FLOW.SAMPLES” = 004200 C END OF PROGRAM04300 GOTO 100 The sub module 224 is configured to provide data which may be used to determine if condenser tubes within the condenser 162 are blocked or fouled. This condition hinders the heat transfer between the water in the tubes and the refrigerant in the shell of the condenser 162. Fouled tubes may be caused by any substance hindering heat transfer including scale (mineral deposits), algae, mud, rust, corrosion, or grease. Condenser tubes foul much more frequently than evaporator tubes, since the latter are part of a closed loop. In the event such a condition develops, then, for a given partial load level, the condenser water differential pressure will be at or close to the design value for the particular partial load. The condenser water differential temperature, however, will be lower than the design value for the particular partial load. Additionally, condenser approach, condenser refrigerant pressure, and condenser refrigerant saturation temperature will be higher than the design value for the particular partial load. In one embodiment, the sub module 224 includes the following commands: 00100 C DEFINE CHILLER NAMING CONVENSION00200 DEFINE (X, “MHS.CHL1”)00300 C DEFINES THE % LOAD DESIGN CRITERIA VALUECOMPARISON00400 IF(“%X%.PLOAD” .GT. 25.0 .AND. “%X%.PLOAD” .LE. 35.0) THEN GOSUB 1400 ″%00500 IF(“%X%.PLOAD” .GT. 35.0 .AND. “%X%.PLOAD” .LE. 45.0) THEN GOSUB 1400 ″%00600 IF(“%X%.PLOAD” .GT. 45.0 .AND. “%X%.PLOAD” .LE. 55.0) THEN GOSUB 1400 ″%00700 IF(“%X%.PLOAD” .GT. 55.0 .AND. “%X%.PLOAD” .LE. 65.0) THEN GOSUB 1400 ″%00800 IF(“%X%.PLOAD” .GT. 65.0 .AND. “%X%.PLOAD” .LE. 75.0) THEN GOSUB 1400 ″%00900 IF(“%X%.PLOAD” .GT. 75.0 .AND. “%X%.PLOAD” .LE. 85.0) THEN GOSUB 1400 ″%01000 IF(“%X%.PLOAD” .GT. 85.0 .AND. “%X%.PLOAD” .LE. 95.0) THEN GOSUB 1400 ″%01100 IF(“%X%.PLOAD” .GT. 95.0) THEN GOSUB 1400“%X%.D100.CWDT”,″%X%.D100.CWDP01200 GOTO 320001300 C SUBROUTINE FOR CONDITIONS WHICH POINT TO FOULED CONDENSER TUBES01400 $LOC1 = 001500 IF(“%X%.CWDT” .LT. $ARG1) THEN $LOC1 = $LOC1 + 101600 IF(“%X%.CWDP” .GT. $ARG2 .AND. “%X%.CWDP” .LT. $ARG3) THEN $LOC1 = $LOC101700 IF(“%X%.CDAP” .GT. $ARG4) THEN $LOC1 = $LOC1 + 101800 IF(“%X%.CDRP” .GT. $ARG5) THEN $LOC1 = $LOC1 + 101900 IF(“%X%.CDRST” .GT. $ARG6) THEN $LOC1 = $LOC1 + 102000 C DETERMINES THE NUMBER OF FLAGS02100 IF(“%X%.STARTED” .EQ. OFF .OR. $LOC1 .NE. 5) THENGOTO 240002200 IF($LOC1 .EQ. 5 .AND. SECNDS .LE. 300) THEN GOTO 260002300 “%X%.FOUL.COND.TUBES.FLAGS” = “%X%.FOUL.COND.TUBES.FLAGS” + 102400 SECNDS = 002500 C DETERMINES TOTAL NUMBER OF SAMPLES02600 IF(“%X%.STARTED” .EQ. OFF) THEN GOTO 290002700 IF(“%X%.STARTED” .EQ. ON .AND. SECND1 .LE. 300) THENGOTO 300002800 “%X%.FOUL.COND.TUBES.SAMPLES” = “%X%.FOUL.COND.TUBES.SAMPLES” + 102900 SECND1 = 003000 RETURN03100 C CALCULATES THE DAILY PERCENTAGE OF DATAWHICH MET THE CRITERIA03200 IF(TIME .NE. 23:59) THEN GOTO 370003300 IF(“%X%.FOUL.COND.TUBES.SAMPLES” .NE. 0) THENGOTO 360003400 “%X%.FOUL.COND.TUBES” = 003500 GOTO 370003600 “%X%.FOUL.COND.TUBES” = “%X%.FOUL.COND.TUBES.FLAGS” / “%X%.FOUL.COND.TUB03700 IF(TIME .NE. 00:00) THEN GOTO 420003800 SECNDS = 003900 SECND1 = 004000 “%X%.FOUL.COND.TUBES.FLAGS” = 004100 “%X%.FOUL.COND.TUBES.SAMPLES” = 004200 C END OF PROGRAM04300 GOTO 100 The sub module 226 is configured to provide data which may be used to determine if evaporator tubes within the evaporator 164 are blocked or fouled. This condition hinders the heat transfer between the water in the tubes and the refrigerant in the shell of the evaporator 164 in a manner similar to that described above with respect to the condenser 162. In the event such a condition develops, then, for a given partial load level, the chilled water differential pressure will be at or close to design parameters for the particular partial load. The chilled water differential temperature, the evaporator refrigerant pressure and the evaporator refrigerant saturation temperature, however, will decrease with respect to the design values for the particular partial load. Additionally, the evaporator approach will increase with respect to the design value for the particular partial load. In one embodiment, the sub module 226 includes the following commands: 00100 C DEFINE CHILLER NAMING CONVENSION00200 DEFINE (X, “MHS.CHL1”)00300 C DEFINES THE % LOAD DESIGN CRITERIA VALUECOMPARISON00400 IF(“%X%.PLOAD” .GT. 25.0 .AND. “%X%.PLOAD” .LE. 35.0) THEN GOSUB 1400 ″%00500 IF(“%X%.PLOAD” .GT. 35.0 .AND. “%X%.PLOAD” .LE. 45.0) THEN GOSUB 1400 ″%00600 IF(“%X%.PLOAD” .GT. 45.0 .AND. “%X%.PLOAD” .LE. 55.0) THEN GOSUB 1400 ″%00700 IF(“%X%.PLOAD” .GT. 55.0 .AND. “%X%.PLOAD” .LE. 65.0) THEN GOSUB 1400 ″%00800 IF(“%X%.PLOAD” .GT. 65.0 .AND. “%X%.PLOAD” .LE. 75.0) THEN GOSUB 1400 ″%00900 IF(“%X%.PLOAD” .GT. 75.0 .AND. “%X%.PLOAD” .LE. 85.0) THEN GOSUB 1400 ″%01000 IF(“%X%.PLOAD” .GT. 85.0 .AND. “%X%.PLOAD” .LE. 95.0) THEN GOSUB 1400 ″%01100 IF(“%X%.PLOAD” .GT. 95.0) THEN GOSUB 1400 “%X%.D100.CHWDT”,″%X%.D100.CHW01200 GOTO 320001300 C SUBROUTINE FOR CONDITIONS WHICH POINT FOULED EVAPORATOR TUBES01400 $LOC1 = 001500 IF(“%X%.CHWDT” .LT. $ARG1) THEN $LOC1 = $LOC1 + 101600 IF(“%X%.CHWDP” .GT. $ARG2 .AND.“%X%.CHWDP” .LT. $ARG3)THEN $LOC1 = $LO01700 IF(“%X%.EVAP” .GT. $ARG4) THEN $LOC1 = $LOC1 + 101800 IF(“%X%.EVRP” .LT. $ARG5) THEN $LOC1 = $LOC1 + 101900 IF(“%X%.EVRST” .LT. $ARG6) THEN $LOC1 = $LOC1 + 102000 C DETERMINES THE NUMBER OF FLAGS02100 IF(“%X%.STARTED” .EQ. OFF .OR. $LOC1 .NE. 5) THENGOTO 240002200 IF($LOC1 .EQ. 5 .AND. SECNDS .LE. 300) THEN GOTO 260002300 “%X%.FOUL.EVAP.TUBES.FLAGS” =“%X%.FOUL.EVAP.TUBES.FLAGS” + 102400 SECNDS = 002500 C DETERMINES TOTAL NUMBER OF SAMPLES02600 IF(“%X%.STARTED” .EQ. OFF) THEN GOTO 290002700 IF(“%X%.STARTED” .EQ. ON .AND. SECND1 .LE. 300) THENGOTO 300002800 “%X%.FOUL.EVAP.TUBES.SAMPLES” = “%X%.FOUL.EVAP.TUBES.SAMPLES” + 102900 SECND1 = 003000 RETURN03100 C CALCULATES THE DAILY PERCENTAGE OF DATAWHICH MET THE CRITERIA03200 IF(TIME .NE. 23:59) THEN GOTO 370003300 IF(“%X%.FOUL.EVAP.TUBES.SAMPLES” .NE. 0) THENGOTO 360003400 “%X%.FOUL.EVAP.TUBES” = 003500 GOTO 370003600 “%X%.FOUL.EVAP.TUBES” =“%X%.FOUL.EVAP.TUBES.FLAGS” / “%X%.FOUL.EVAP.TUB03700 IF(TIME .NE. 00:00) THEN GOTO 420003800 SECNDS = 003900 SECND1 = 004000 “%X%.FOUL.EVAP.TUBES.FLAGS” = 004100 “%X%.FOUL.EVAP.TUBES.SAMPLES” = 004200 C END OF PROGRAM04300 GOTO 100 The sub module 228 is configured to provide data which may be used to determine if non-condensable gases are present in the refrigerant system. Generally, temperature and pressure maintained in the condenser 162 allows the refrigerant to change state from a vapor to a liquid by releasing heat to the condenser water. Thus, the refrigerant enters the condenser 162 as a vapor and it leaves the condenser 162 as a liquid. The temperature difference between the refrigerant in its vapor state and its leaving liquid state is normally within 2° F. (1° C.). The presence of non-condensable gases, however, raises the condenser pressure (and corresponding temperature), resulting in a temperature differential greater than 2° F. (1° C.) between the temperature of the refrigerant in the condenser 162 and the temperature of the liquid refrigerant leaving the condenser 162. Other than the temperature differential, the only indication for the above condition is the run-time of the purge pump. In the event such a condition develops, then, for a given partial load level, the condenser water differential temperature, the condenser water differential pressure and the condenser approach will be at or close to the design values for the particular partial load level. The temperature difference between the condensing gauge temperature and the condensing liquid temperature will be greater than two degrees and the compressor discharge temperature will be greater than the design value for the particular partial load level. Additionally, the purge run time or cycles will be higher than the design purge run time or cycles for the particular partial load level. In one embodiment, the sub module 228 includes the following commands: 00100 C DEFINE CHILLER NAMING CONVENSION00200 DEFINE (X, “MHS.CHL1”)00300 C “PURGE.COUNT” REPRESENTS THE NUMBER OF00400 C TIMES THE PURGE PRESSURE EXCEEDED 90 PSI. AT THIS PRESSURE THE00500 C PURGE UNIT WILL ENERGIZE TO EXHAUSTNONCONSENSABLES FROM THE CHILLER00600 C MOTOR.00700 IF(“%X%.PURGE” .GE. 90) THEN ON($LOC2)00800 IF(“%X%.PURGE” .GT. 80 .AND. $LOC2 .EQ. ON) THENGOTO 130000900 IF($LOC2 .EQ. OFF) THEN GOTO 130001000 “%X%.PURGECOUNT” = “%X%.PURGECOUNT” + 101100 $LOC2 = OFF01200 C DEFINES THE % LOAD DESIGN CRITERIA VALUECOMPARISON01300 IF(“%X%.PLOAD” .GT. 25.0 .AND. “%X%.PLOAD” .LE. 35.0) THEN GOSUB 2300 ″%01400 IF(“%X%.PLOAD” .GT. 35.0 .AND. “%X%.PLOAD” .LE. 45.0) THEN GOSUB 2300 ″%01500 IF(“%X%.PLOAD” .GT. 45.0 .AND. “%X%.PLOAD” .LE. 55.0) THEN GOSUB 2300 ″%01600 IF(“%X%.PLOAD” .GT. 55.0 .AND. “%X%.PLOAD” .LE. 65.0) THEN GOSUB 2300 ″%01700 IF(“%X%.PLOAD” .GT. 65.0 .AND. “%X%.PLOAD” .LE. 75.0) THEN GOSUB 2300 ″%01800 IF(“%X%.PLOAD” .GT. 75.0 .AND. “%X%.PLOAD” .LE. 85.0) THEN GOSUB 2300 ″%01900 IF(“%X%.PLOAD” .GT. 85.0 .AND. “%X%.PLOAD” .LE. 95.0) THEN GOSUB 2300 ″%02000 IF(“%X%.PLOAD” .GT. 95.0) THEN GOSUB 2300 “%X%.D100.CWDT.LO”,″%X%.D100.C02100 GOTO 500002200 C SUBROUTINE FOR CONDITIONS WHICH POINT TO NON-CONDENSABLES IN THE02300 $LOC1 = 002400 IF(“%X%.CWDT” .GT. $ARG1 .AND. “%X%.CWDT” .LT. $ARG2) THEN $LOC1 = $LOC102500 IF(“%X%.CWDP” .GT. $ARG3 .AND. “%X%.CWDP” .LT. $ARG4) THEN $LOC1 = $LOC102600 IF(“%X%.CDAP” .GT. $ARG5 .AND. “%X%.CDAP” .LT. $ARG6) THEN $LOC1 = $LOC102700 IF(“%X%.CDRP” .GT. $ARG7) THEN $LOC1 = $LOC1 + 102800 IF(“%X%.CDT” .GT. $ARG8) THEN $LOC1 = $LOC1 + 102900 C DETERMINES IF PURGE CYCLE IS PRESENT03000 IF(“%X%.PURGE.AVAL” .EQ. ON) THEN GOTO 380003100 C DETERMINES THE NUMBER OF FLAGS IF PURGECYCLE IS NOT PRESENT03200 IF(“%X%.STARTED” .EQ. OFF .OR. $LOC1 .LT. 5) THENGOTO 350003300 IF($LOC1 .GE. 5 .AND. SECNDS .LE. 300) THEN GOTO 360003400 “%X%.NONCONDENSABLES.FLAGS” = “%X%.NONCONDENSABLES.FLAGS” + 103400 “%X%.NONCONDENSABLES.FLAGS” = “%X%.NONCONDENSABLES.FLAGS” + 103500 SECNDS = 003600 GOTO 440003700 C DETERMINES THE NUMBER OF FLAGS IF PURGE IS CYCLE PRESENT03800 IF(“%X%.PURGECOUNT” .GE. “%X%.PURGECOUNT.SP”)THEN $LOC1 = $LOC1 + 103900 IF(“%X%.STARTED” .EQ. OFF .OR. $LOC1 .LT. 6) THENGOTO 420004000 IF($LOC1 .GE. 6 .AND. SECND2 .LE. 300) THEN GOTO 440004100 “%X%.NONCONDENSABLES.FLAGS” = “%X%.NONCONDENSABLES.FLAGS” + 104200 SECND2 = 004300 C DETERMINES TOTAL NUMBER OF SAMPLES04400 IF(“%X%.STARTED” .EQ. OFF) THEN GOTO 470004500 IF(“%X%.STARTED” .EQ. ON .AND. SECND1 .LE. 300) THENGOTO 480004600 “%X%.NONCONDENSABLES.SAMPLES” = “%X%.NONCONDENSABLES.SAMPLES” + 104700 SECND1 = 004800 RETURN04900 C CALCULATES THE DAILY PERCENTAGE OF DATAWHICH MET THE CRITERIA05000 IF(TIME .NE. 23:59) THEN GOTO 550005100 IF(“%X%.NONCONDENSABLES.SAMPLES” .NE. 0) THENGOTO 540005200 “%X%.NONCONDENSABLES” = 005300 GOTO 550005400 “%X%.NONCONDENSABLES” =“%X%.NONCONDENSABLES.FLAGS” / “%X%.NONCONDENSABL05500 IF(TIME .NE. 00:00) THEN GOTO 620005600 SECNDS = 005700 SECND1 = 005800 SECND2 = 005900 “%X%.PURGECOUNT” = 006000 “%X%.NONCONDENSABLES.FLAGS” = 006100 “%X%.NONCONDENSABLES.SAMPLES” = 006200 C END OF PROGRAM06300 GOTO 100 The sub module 230 is configured to provide data which may be used to determine if there is a low refrigerant level in the system. Low refrigerant levels may result from a leak or from refrigerant building up or “stacking” in the condenser 162. Conditions leading to stacking include a condenser water temperature that is below the manufacturer's minimum design value. Refrigerant stacking in the condenser will not drive the condenser pressure up. Rather, the temperature in the condenser 162 will sub cool to nearly the entering condenser water temperature. In the event such a condition develops, then, for a given partial load level, the chilled water differential pressure will be at or close to the design values for the particular partial load level. The chilled water differential temperature, the evaporator pressure, the compressor motor current and the evaporator refrigerant saturation temperature will be lower than the design value for the particular partial load level. Additionally, the evaporator approach and compressor discharge temperature will be higher than the design value for the particular partial load level. In one embodiment, the sub module 230 includes the following commands: 00100 C DEFINE CHILLER NAMING CONVENSION00200 DEFINE (X, “MHS.CHL1”)00300 C DEFINES THE % LOAD DESIGN CRITERIA VALUECOMPARISON00400 IF(“%X%.PLOAD” .GT. 25.0 .AND. “%X%.PLOAD” .LE. 35.0) THEN GOSUB 1400 ″%00500 IF(“%X%.PLOAD” .GT. 35.0 .AND. “%X%.PLOAD” .LE. 45.0) THEN GOSUB 1400 ″%00600 IF(“%X%.PLOAD” .GT. 45.0 .AND. “%X%.PLOAD” .LE. 55.0) THEN GOSUB 1400 ″%00700 IF(“%X%.PLOAD” .GT. 55.0 .AND. “%X%.PLOAD” .LE. 65.0) THEN GOSUB 1400 ″%00800 IF(“%X%.PLOAD” .GT. 65.0 .AND. “%X%.PLOAD” .LE. 75.0) THEN GOSUB 1400 ″%00900 IF(“%X%.PLOAD” .GT. 75.0 .AND. “%X%.PLOAD” .LE. 85.0) THEN GOSUB 1400 ″%01000 IF(“%X%.PLOAD” .GT. 85.0 .AND. “%X%.PLOAD” .LE. 95.0) THEN GOSUB 1400 ″%01100 IF(“%X%.PLOAD” .GT. 95.0) THEN GOSUB 1400 “%X%.D100.CHWDT”,″%X%.D100.CHW01200 GOTO 340001300 C SUBROUTINE FOR CONDITIONS WHICH POINT TO LOW REFRIGERANT LEVELS01400 $LOC1 = 001500 IF(“%X%.CHWDT” .LT. $ARG1) THEN $LOC1 = $LOC1 + 101600 IF(“%X%.CHWDP” .GT. $ARG2 .AND.“%X%.CHWDP” .LT. $ARG3)THEN $LOC1 = $LO01700 IF(“%X%.EVAP” .GT. $ARG4) THEN $LOC1 = $LOC1 + 101800 IF(“%X%.EVRP” .LT. $ARG5) THEN $LOC1 = $LOC1 + 101900 IF(“%X%.CDT” .GT. $ARG6) THEN $LOC1 = $LOC1 + 102000 IF(“%X%.EVRST” .LT. $ARG7) THEN $LOC1 = $LOC1 + 102100 IF(“%X%.CURRENT” .LT. $ARG8) THEN $LOC1 = $LOC1 + 102200 C DETERMINES THE NUMBER OF FLAGS02300 IF(“%X%.STARTED” .EQ. OFF .OR. $LOC1 .NE. 7) THENGOTO 260002400 IF($LOC1 .EQ. 7 .AND. SECNDS .LE. 300) THEN GOTO 280002500 “%X%.LO.REF.LVL.FLAGS” =“%X%.LO.REF.LVL.FLAGS” + 102600 SECNDS = 002700 C DETERMINES TOTAL NUMBER OFLO.REF.LVL.SAMPLES02800 IF(“%X%.STARTED” .EQ. OFF) THEN GOTO 310002900 IF(“%X%.STARTED” .EQ. ON .AND. SECND1 .LE. 300) THENGOTO 320003000 “%X%.LO.REF.LVL.SAMPLES” =“%X%.LO.REF.LVL.SAMPLES” + 103100 SECND1 = 003200 RETURN03300 C CALCULATES THE DAILY PERCENTAGE OF DATAWHICH MET THE CRITERIA03400 IF(TIME .NE. 23:59) THEN GOTO 390003500 IF(“%X%.LO.REF.LVL.SAMPLES” .NE. 0) THEN GOTO 380003600 “%X%.LO.REF.LVL” = 003700 GOTO 390003800 “%X%.LO.REF.LVL” = “%X%.LO.REF.LVL.FLAGS” / “%X%.LO.REF.LVL.SAMPLES” * 103900 IF(TIME .NE. 00:00) THEN GOTO 440004000 SECNDS = 004100 SECND1 = 004200 “%X%.LO.REF.LVL.FLAGS” = 004300 “%X%.LO.REF.LVL.SAMPLES” = 004400 C END OF PROGRAM04500 GOTO 100 The sub module 232 is configured to provide data which may be used to determine chiller oil conditions. Oil used in the refrigerant cycle lubricates the moving parts of the compressor 166 and also acts as a cooling medium, removing the heat of friction from the compressor bearings. High and low oil temperature, as well as low oil pressure, are safety cutouts for the chiller 160. If the oil exceeds these safety limits, these cutouts will stop the compressor 166 automatically. The oil temperature can get too high if loss of oil cooling occurs or if a bearing failure causes excessive heat generation. The oil temperature can get too low if an oil heater failure occurs. A low oil temperature cutout will also prevent the compressor 166 from starting after a prolonged shutdown, and before the oil heaters have had time to drive off the refrigerant dissolved in the oil. The oil pressure can get too low if oil filters become clogged, oil passageways become blocked, there is a loss of oil, or if the oil pump fails. This cutout shuts down the compressor 166 when oil pressure drops below a minimum safe value or if sufficient oil pressure is not developed shortly after compressor startup. Another potential condition related to the chiller oil is excessive oil in the evaporator 164. When the chiller 160 is operating properly, a small amount of oil mixes and travels with the refrigerant through the entire chiller 160, from the compressor 166 to the condenser 162 to the evaporator 164 and back to the compressor crankcase before that segment of the system is pumped short of oil. The oil is not always properly moved from the evaporator 164 through the suction line back to the compressor 166. When this does not occur, the evaporator 164 becomes oil-logged, decreasing the heat transfer surface of the cooling coil and thus the chiller efficiency. Accordingly, oil conditions present observables which are similar to those for low refrigerant in the system, as well as fouled evaporator tubes. Thus, when oil conditions arise, the temperature drop between the chilled water return header 174 and the chilled water supply header 172 along with refrigerant pressure decrease while the approach temperature increases. In some cases, the refrigerant liquid temperature and the compressor discharge temperature may be less than the design limit. In the event such a condition develops, then, for a given partial load level, the chilled water differential pressure will be at or close to the design values for the particular partial load level. The chilled water differential temperature, the evaporator refrigerant pressure, the compressor discharge temperature and the evaporator refrigerant saturation temperature will be lower than the design value for the particular partial load level. Additionally, the evaporator approach will be higher than the design value for the particular partial load level. In one embodiment, the sub module 232 includes the following commands for determining if there is excessive oil in the evaporator: 00100 C DEFINE CHILLER NAMING CONVENSION00200 DEFINE (X, “MHS.CHL1”)00300 C DEFINES THE % LOAD DESIGN CRITERIA VALUECOMPARISON00400 IF(“%X%.PLOAD” .GT. 25.0 .AND. “%X%.PLOAD” .LE. 35.0) THEN GOSUB 1400 “%00500 IF(“%X%.PLOAD” .GT. 35.0 .AND. “%X%.PLOAD” .LE. 45.0) THEN GOSUB 1400 “%00600 IF(“%X%.PLOAD” .GT. 45.0 .AND. “%X%.PLOAD” .LE. 55.0) THEN GOSUB 1400 “%00700 IF(“%X%.PLOAD” .GT. 55.0 .AND. “%X%.PLOAD” .LE. 65.0) THEN GOSUB 1400 “%00800 IF(“%X%.PLOAD” .GT. 65.0 .AND. “%X%.PLOAD” .LE. 75.0) THEN GOSUB 1400 “%00900 IF(“%X%.PLOAD” .GT. 75.0 .AND. “%X%.PLOAD” .LE. 85.0) THEN GOSUB 1400 “%01000 IF(“%X%.PLOAD” .GT. 85.0 .AND. “%X%.PLOAD” .LE. 95.0) THEN GOSUB 1400 “%01100 IF(“%X%.PLOAD” .GT. 95.0) THEN GOSUB 1400 “%X%.D100.CHWDT”,“%X%.D100.CHW01200 GOTO 330001300 C SUBROUTINE FOR CONDITIONS WHICH POINT TO OIL IN THE EVAPORATOR01400 $LOC1 = 001500 IF(“%X%.CHWDT” .LT. $ARG1) THEN $LOC1 = $LOC1 + 101600 IF(“%X%.CHWDP” .GT. $ARG2 .AND.“%X%.CHWDP” .LT. $ARG3)THEN $LOC1 = $LO01700 IF(“%X%.EVAP” .GT. $ARG4) THEN $LOC1 = $LOC1 + 101800 IF(“%X%.EVRP” .LT. $ARG5) THEN $LOC1 = $LOC1 + 101900 IF(“%X%.CDT” .LT. $ARG6) THEN $LOC1 = $LOC1 + 102000 IF(“%X%.EVRST” .LT. $ARG7) THEN $LOC1 = $LOC1 + 102100 C DETERMINES THE NUMBER OF FLAGS02200 IF(“%X%.STARTED” .EQ. OFF .OR. $LOC1 .NE. 6) THENGOTO 250002300 IF($LOC1 .EQ. 6 .AND. SECNDS .LE. 300) THEN GOTO 270002400 “%X%.OIL.IN.EVAP.FLAGS” =“%X%.OIL.IN.EVAP.FLAGS” + 102500 SECNDS = 002600 C DETERMINES TOTAL NUMBER OF SAMPLES02700 IF(“%X%.STARTED” .EQ. OFF) THEN GOTO 300002800 IF(“%X%.STARTED” .EQ. ON .AND. SECND1 .LE. 300) THENGOTO 310002900 “%X%.OIL.IN.EVAP.SAMPLES” =“%X%.OIL.IN.EVAP.SAMPLES” + 103000 SECND1 = 003100 RETURN03200 C CALCULATES THE DAILY PERCENTAGE OF DATAWHICH MET THE CRITERIA03300 IF(TIME .NE. 23:59) THEN GOTO 380003400 IF (“%X%.OIL.IN.EVAP.SAMPLES” .NE. 0) THEN GOTO 370003500 “%X%.OIL.IN.EVAP” = 003600 GOTO 0360003700 “%X%.OIL.IN.EVAP” = (“%X%.OIL.IN.EVAP.FLAGS” / “%X%.OIL.IN.EVAP.SAMPLES”03800 IF(TIME .NE. 00:00) THEN GOTO 430003900 SECNDS = 004000 SECND1 = 004100 “%X%.OIL.IN.EVAP.FLAGS” = 004200 “%X%.OIL.IN.EVAP.SAMPLES” = 004300 C END OF PROGRAM04400 GOTO 100 Monitoring the health of a system is discussed with reference to the method 240 of FIG. 7. At the step 242, benchmark data is obtained. The benchmark data may be obtained from design values for the system or device from the manufacturer of the system or device. Preferably, however, benchmark data for the system or equipment is obtained during actual operations as this approach develops the most accurate data. It is further preferred to obtain benchmarking data is at a number of different system capacity levels. In accordance with one embodiment, benchmark data for the chilled water system 158 is obtained at system capacity levels between about 100% and 40%. To obtain the best data, the chilled water system 158 is inspected to ensure that it is operating at peak condition. When this condition has been established, parameters should be collected at various system capacity levels. The table below lists the parameters collected in this example. TABLE 1Trended points for BenchmarkingDescriptionPoint TypePoint NamePercent LoadCalculation (PPCL)CHL#: PLOADMaximum CapacityConstantCHL#: MAXCAPChilled Water FlowConstantCHL#: CHWFLOWChilled WaterCalculationCHL# .CHWDTTemperatureDifferentialChilled WaterPhysicalCHL# .CHWDPPressureDifferentialEvaporator WaterCalculation (PPCL)CHL# .EVAPApproachTemperatureEvaporatorPhysicalCHL#: EVAPSAT TEMPSaturationTemperatureEvaporatorPhysicalCHL#: EVAP PRESSRefrigerant PressureCondenser WaterCalculationCHL# .CWDTTemperatureDifferentialCondenser WaterPhysicalCHL# .CWDPPressureDifferentialCondenser WaterCalculation (PPCL)CHL# .CDAPApproachTemperatureCondenserPhysicalCHL#: CONDSAT TEMPSaturationTemperatureCondenserPhysicalCHL#: COND PRESSRefrigerant PressureCompressorPhysicalCHL#: COMPDISCH TDischargeTemperatureMotor CurrentPhysicalCHL#: PHA CURR While some of the foregoing parameters, such as chilled water flow, chilled water differential pressure, condenser water differential pressure, and maximum chiller capacity, may preferably be collected manually from equipment or facility data, data identified in Table 1 may alternatively be obtained from the sensors in the system through the data network 130. Initially, the system is configured to run at full load. This may be accomplished by dropping the chilled water temperature setpoint to create a load on the chiller 160. The chiller 160 will gradually respond to the perceived load. Once the chiller 160 has reached a steady state condition, the various parameters are logged or collected. Preferably, the steady state condition is maintained for at least five minutes to obtain a number of different data samples. After sufficient data has been collected, the chilled water set point may be incrementally raised to replicate system partial loads. In one embodiment, the set point is modified so as to replicate system partial loads in 10% increments from 100% down to about 40%. As with the previous sequence, once the chiller has reached a steady state condition, the various parameters are logged or collected. Preferably, the steady state condition is maintained for at least five minutes to obtain a number of different data samples. Once all the benchmark data has been collected, the data for the particular system capacity levels is averaged to obtain a benchmark value for each parameter. This benchmark data for each parameter at each of the system capacity levels represents a condition of the chilled water system 158 wherein no degradation of system health has occurred. Thereafter, at the step 244 the chilled water system 158 is operated in a normal manner. Thus, as the load on the chilled water system 158 fluctuates over a period of time, the controller 108 controls the chilled water system 158 to provide the requisite amount of chilled water at the requisite temperature through the chilled water supply header 172. As the chilled water system 158 operates, data indicative of the operational parameters is obtained at the step 246. This data may be obtained from the sensors 176-210 and communicated to the controller 108 and then through the data network 128 to the supervisory control system 102 and stored in the system database 104 or a temporary storage. Alternatively, data may be manually obtained and entered into the database 104. In one embodiment, the data includes a date/time stamp or is otherwise identifiable with the time the data was obtained. The operational data is thereafter analyzed at the step 248 to identify data obtained during steady state operations. This analysis may be performed continuously in near real time or the operational data may be stored for later retrieval and analysis. When the process 240 is run in near real time, an analysis window is set to be open-ended. Thus, as data becomes available, the data is analyzed. When the process 240 is run against archived data, a stop time may be identified for the analysis window. In either event, a start time for the analysis window may be identified. In either approach, a minimum data window may be used to ensure that all of the system parameters are stable. In the present example, a steady state data window is identified as five minutes of data that indicates steady state conditions within the chilled water system 158. As a part of the step 248, the health monitoring program may check to ensure that the steady state conditions are at a sufficiently high level of capacity to ensure the data obtained is valid. By way of example, when a chiller is run below about 40% capacity, the operating parameters are not consistent. Accordingly, operational data obtained while the chiller is running below a 40% load capacity, in this example, are not used for health monitoring. The data may nonetheless be useful. One use of the data is to identify the amount of time that a chiller is operated at various loads. This information is of use because the efficiency of a particular chiller is highly dependent upon the load at which the chiller is run. At a loading less than about 40% of the chiller load capacity, chillers are very inefficient. Accordingly, for a two chiller system operating at a 60% system load, loading both chillers at 60% is more efficient than loading one chiller at 85% and loading the second chiller to 35%. Accordingly, this data may be used to assist in optimizing the system efficiency. In one embodiment, a program establishing a minimum level of capacity for execution of the sub modules includes the following: 00100 C DEFINE CHILLER NAMING CONVENSION00200 DEFINE (X, “MHS.CHL1”)00300 C DETERMINES IF LOW LOAD CONDITIONS EXIST00400 $LOC1 = 000500 IF(“%X%.PLOAD” .LE. 25.0) THEN $LOC1 = $LOC1 + 100600 C DETERMINES THE NUMBER OF FLAGS00700 IF(“%X%.STARTED” .EQ. OFF .OR. $LOC1 .NE. 1) THENGOTO 100000800 IF($LOC1 .EQ. 1 .AND. SECNDS .LE. 300) THEN GOTO 120000900 “%X%.LOW.LOAD.FLAGS” = “%X%.LOW.LOAD.FLAGS” + 101000 SECNDS = 001100 C DETERMINES TOTAL NUMBER OF SAMPLES01200 IF(“%X%.STARTED” .EQ. OFF) THEN GOTO 150001300 IF(“%X%.STARTED” .EQ. ON .AND. SECND1 .LE. 300) THENGOTO 170001400 “%X%.LOW.LOAD.SAMPLES”= “%X%.LOW.LOAD.SAMPLES” + 101500 SECND1 = 001600 C CALCULATES THE DAILY PERCENTAGE OF DATAWHICH MET THE CRITERIA01700 IF(TIME .NE. 23:59) THEN GOTO 220001800 IF(“%X%.LOW.LOAD.SAMPLES” .EQ. 0) THEN GOTO 210001900 “%X%.LOW.LOAD” = “%X%.LOW.LOAD.FLAGS” / “%X%.LOW.LOAD.SAMPLES” * 10002000 GOTO 220002100 “%X%.LOW.LOAD” = 002200 IF(TIME .NE. 00:00) THEN GOTO 270002300 SECNDS = 002400 SECND1 = 002500 “%X%.LOW.LOAD.FLAGS” = 002600 “%X%.LOW.LOAD.SAMPLES” = 002700 C END OF PROGRAM02800 GOTO 100 If the criteria for a steady state data window are not met, then the process proceeds to the step 250 and waits for additional data. If, however, the criteria for a steady state data window are met, then a steady state data flag is set for the data sample window at the step 252 and at the step 254 the health sub modules are executed as discussed in more detail below. After the health sub modules have been executed, the method proceeds to the step 256. At the step 256, the method determines if any additional operational data is available for analysis. If more data is available, then the process 240 proceeds to the step 258 and determines if the analysis window is still open. If the data analyzed is the last data available for analysis in the identified analysis window, then the process 240 proceeds to the step 260 and ends. If, however, the analysis window is still open, then the process 240 returns to the step 246 and obtains the additional data and the step 248 is repeated. If there is no additional data or an insufficient amount of data at the step 256, then the method determines whether or not the system is still being operated at the step 262. If the system is not being operated and there is no additional data, then either the process 240 is being run on archived data and all data has been processed or the process had been running in near real time but the system was just shut down. In either event, there is no further data to evaluate and the process 240 ends at the step 260. If the system is still being operated at the step 262 the process proceeds to the step 264 and determines if the analysis window is still open. If the data analyzed is the last data available for analysis in the identified analysis window, then the process 240 proceeds to the step 260 and ends. If, however, the analysis window is still open, such as when the process 240 is run in near real time, then the process 240 returns to the step 250 and waits for additional data. The execution of the health sub modules 216-232 of step 254 are described with reference to the method 270 of FIG. 8. The method 270 initially determines the capacity level at which the system was operated during the steady state sample window identified at the step 248 of FIG. 7 at the step 272. In accordance with this example, benchmark data was obtained in step 242 for system capacity levels from 100% to 40% in 10% increments and the steady state data window identified at the step 248 is correlated with the closest benchmarked capacity level. Thus, operational data obtained while the chilled water system 158 was operating at 74% capacity may be correlated with benchmark data obtained at system capacity level of 70%. At the step 274, the operational data for the particular sample window are retrieved. If the process 270 is operating on archived data, then data stored in the database 104 for a parameter associated with identifying the condition of the particular health sub module is retrieved. If the process 270 is running in real-time, then the data may be in a temporary storage, register, or the like. The benchmark data for the parameter associated with identifying the condition of the particular health sub module for the capacity level at which the system was operated during the steady state window is retrieved at the step 276. The data is correlated at the step 278 and a comparison flag is set at the step 280. The method at the step 282 then determines if the parameter data retrieved in the step 274 meets a criterion for a condition being present based upon the benchmark data retrieved at the step 276. If the criterion is not met, then the method skips to the step 286. If the criterion is met, then at the step 284 a parameter flag is set and the method continues to the step 286. If additional data is available for comparison at the step 286, either for the parameter just analyzed or for another parameter associated with identifying the condition of the particular health sub module, then the system returns to the step 274. If there is no additional data to be analyzed with respect to the condition of the particular health sub module, then the method proceeds to the step 288 and compares the number of comparison flags set at the step 280 with the number of parameter flags set at the step 284. If there are fewer parameter flags than comparison flags, then all of the parameters associated with the condition of the particular health sub module did not meet the criteria for determining that the health condition was present. Accordingly, at the step 290, the steady state data sample window is identified as not having the condition present and the results of the analysis are saved. If, however, there is an equal number of comparison flags and parameter flags, then all of the parameters associated with the health condition of the particular health sub module met the criteria for determining that the health condition was present. Accordingly, at the step 292, the steady state data sample window is identified as having the health condition present and the results of the analysis are saved. In either event, the method ends at the step 294. The results of the analysis of FIG. 7 and FIG. 8 may be used in a number of ways. For example, the results may be displayed in the form of a print out or a visual display. The results may also be used to provide alarms and/or to facilitate further analysis for a particular condition. The method depicted in FIG. 9 may be used to generate displays and alarms and to facilitate further analysis. With reference to FIG. 9, the process 300 begins with the step 302 wherein the analysis window for the particular condition which is desired to be trended is identified. When the process 300 is run in real-time, the analysis window set at the step 302 in this embodiment is the same analysis step discussed above with respect to the step 246 of FIG. 7 and the analysis window is set tot be open ended. At the step 304 the granularity or data interval of the display is established. By way of example, an analysis window of two months may be selected with a time interval of one day. The analysis window may be a fixed two month window or the analysis window may be open ended so as to provide near real time data along with the past two months worth of data. Next, the condition present data for the first interval, which was stored at the step 292 of FIG. 8, is obtained at the step 306. Additionally, the number of steady state data sample windows during the interval is obtained at the step 308. In this embodiment, this is accomplished by determining the number of steady state data flags that were set at the step 252 for data sample windows which occurred during the interval. At the step 310, the number of condition present data from the step 306 is divided by the number of flags retrieved at the step 308. This generates a percentage of the steady state operating windows during the interval during which all of the parameters indicative of a particular condition were present. This data is stored at the step 312 and at the step 314, the display of the percentage data is updated. If there are additional intervals in the window to be analyzed at the step 316, then the method proceeds to the step 306 and retrieves the condition present data for the next interval. If all of the intervals for the identified window have already been analyzed, the process ends at the step 318. In this embodiment, a display is rendered visually at the supervisory control system in the form of a chart identifying the percentage of data that met the criteria for the particular condition being evaluated. FIGS. 10-13 depict exemplary results of the method of FIG. 9. FIG. 10 depicts a printout of the percentage of daily samples that met the criteria for having fouled condenser tubes. FIG. 11 depicts a printout of the percentage of daily samples that met the criteria for having low refrigerant level. FIG. 12 depicts a printout of the percentage of daily samples that met the criteria for having noncondensables in the system. FIG. 13 depicts a printout of the percentage of daily samples that met the criteria for having oil in the evaporator. In addition to providing a display, the health monitoring program 214 may be programmed to provide alerts if predetermined percentages of data stored at the step 294 are indicative of a condition. By way of example, a warning may be provided if 70% of the comparisons exceed an acceptance criteria based upon the benchmark data and an alarm may be provided if 90% of the comparisons exceed the acceptance criteria. Moreover, the display of the health data generated by the health monitoring program as shown in FIGS. 10-13 may be used to understand the condition of a system even if no single parameter exceeds its normal operating range. By way of example, a review of the data presented in FIG. 13 reveals a steady overall upward trend in the percentage of daily samples that met the criteria for having oil in the evaporator. Therefore, even if there has not been an alarm based upon a sensor detecting an out of limits condition, the operators can determine that the system will soon experience such alarms if corrective action is not taken. It will be appreciated that the above describe embodiments are merely exemplary, and that those of ordinary skill in the art may readily devise their own modifications and implementations that incorporate the principles of the present invention and fall within the spirit and scope thereof.
	summary
052290689	description	DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, 2A and 2B, the prior art construction of a fuel bundle can be understood insofar as it is relevant here. A fuel bundle B is illustrated, having a channel C with an upper tie plate U and a lower tie plate L. A plurality of fuel rods R are supported on the lower tie plate L, and extend upwardly to and toward the upper tie plate U. In the embodiment here shown, a large central water rod W is utilized. Operation of the fuel bundle as part of a core in a large boiling water reactor (not shown) can be understood. Water enters through lower tie plate L. The water passes through upwardly and about the rods R. During this passage, steam is generated. Finally, a steam and water mixture passes outwardly up and through the upper tie plate U. During the steam generation, channel C isolates the core bypass volume from the flow interior of the fuel bundle. As shown in FIG. 1, and 3A, seven spacers S.sub.1 -S.sub.7 are normally utilized. These spacers are shown respectively in FIGS. 2A and 2B. With respect to FIG. 2A, spacers S.sub.5 through S.sub.1 occupying positions in the lower portion of the fuel bundle B are illustrated for a 9 by 9 fuel rod matrix. These spacers surround the large water rod W and maintain individual rods at their discrete elevations in the proper alignment. Referring to FIG. 2B, the upper spacers S.sub.6 and S.sub.7 are illustrated. These respective spacers raise the rod matrix above the termination of the so-called "part length rod." As of this writing, the preferred embodiment of this invention includes the 9 by 9 array of FIGS. 1, 2A and 2B. With respect to FIG. 2C, spacers S.sub.5 through S.sub.1 occupying positions in the lower portion of a fuel bundle similar to fuel bundle B are illustrated for a 10 by 10 fuel rod matrix. These spacers surround the large water rod W and maintain individual rods at their discrete elevations in the proper alignment. Referring to FIG. 2D, the upper spacers S.sub.6 and S.sub.7 are illustrated. These respective spacers raise the rod matrix above the termination of the so-called "part length rod." Referring to Dix et al., U.S. Pat. No. 5,112,570, issued May 12, 1992 entitled TWO-PHASE PRESSURE DROP REDUCTION BWR ASSEMBLY U.S. patent application Ser. No. 07/176,975 filed Apr. 4, 1988) In that application, it was disclosed to place within the fuel bundle a group of part length rods P. Simply stated, and above spacer S.sub.5 and before spacers S.sub.6 and S.sub.7, part length rods P were utilized. The part length rods were supported on the lower tie plate L. They extended up to and through spacer 5. They terminated a short distance above spacer 5. From their point of termination above spacer 5, the part length rods P define voids in the upper two-phase region of the fuel bundle. Benefits are realized from this construction. These have been set forth above. As the reader undoubtedly further understands, we have, through extensive testing, discovered that critical power is less than anticipated in the upper two-phase region of the illustrated fuel bundle compared with all full length rods in the bundle. That is to say, above the part length rods and through the end of the active fuel of the full length fuel rods R, critical power conditions may be met prematurely at the fuel rods. This being the case, the entire bundle must be limited so that at no individual point on any individual fuel rod R, the critical power limitations are exceeded. Referring to FIGS. 3A through 3F, the invention herein is schematically illustrated. FIG. 3A, only, represents prior art. Specifically, only two elements are illustrated. First, there is a bar graph 40. Bar graph 40 shows seven spacers S.sub.1 -S.sub.7, all on 20 inch centers. Secondly, there is a partial length rod P illustrated. Partial length rod P is shown being approximately 102" in length, and terminating just above spacer S.sub.5. This bar graph illustrates the construction set forth in FIG. 1. FIG. 3B is our preferred embodiment. Specifically, it constitutes a configuration on which actual tests have been run. Partial length rod P is 102" in length. Spacer distribution from spacer S.sub.1 through spacer S.sub.5 is the same as it has been before. Spacers S.sub.6, S.sub.7 and S.sub.8 are on respective 13.3" centers. As the reader will understand, an additional spacer S.sub.8 has been added. In all of the embodiments that follow, the reader will understand that the additional spacers are more than that number required to maintain the rods against rod bow and in their design side by side relation. Further, the spacers are ferrule-type spacers, utilizing a relatively thin zircaloy metal (in the thicknesses generally about 20/1000ths of an inch). It has been found that improved critical power results. Once the configuration of FIG. 3B is understood, other possible configurations suggest themselves. They will be briefly addressed below. With respect to FIG. 3C, bar graph 40 shows a part length rod approximately 115" long, extending up to, through and including spacer S.sub.6. The spacer separation is the same as FIG. 3B. Referring to FIG. 3D, a part length rod 113" is utilized. The spacing of the spacers differs only above spacer S.sub.4. From spacer S.sub.4 through spacer S.sub.8 the spacers are on 15" centers. Regarding FIG. 3E, it will be understood that the spacing of the spacers remains the same as in FIG. 3D. However, the part length rod is 97" long, and thus is braced at spacer S.sub.5. Regarding FIG. 3F, the design there appears to have potential even exceeding our preferred embodiment which we illustrate in FIG. 3B. As of the writing of this patent application, this configuration has not been specifically tested. We therefore do not claim it as our preferred embodiment, but do call to the attention of the reader the fact that this design may be beneficial. Simply stated, and above spacer S.sub.4, the pitch of the spacers S.sub.5, S.sub.6, S.sub.7 and S.sub.8 gradually decreases. The partial length rod used with the design is 116" in length, and extends through spacer S.sub.6. Specifically, between spacer S.sub.4 and S.sub.5 an 18" separation is utilized. Between spacer S.sub.5 and S.sub.6, a 16" separation is utilized. Between spacers S.sub.6 and S.sub.7, a 14" spacing is utilized. Finally, between spacers S.sub.6 and S.sub.8, a 12" spacing is utilized. The reader will realize that in this latter design, decreasing spacer pitch occurs at that portion of the fuel bundle wherein the void fraction increases. It has been found in addition to the increased spacer pitch, that spacers incorporating swirl vane constructions in the upper two phase region of the fuel bundle in conjunction with partial length rods have the same overall beneficial effect. Specifically, critical power is increased even though the insertion of the spacers having the swirl vanes tends to restore some--if not all--of the improved pressure drop in the upper two phase region of the fuel bundle. Accordingly, the following constructions are exemplary of spacers which when left on a regular pitch through the incorporation of swirl vanes produce an increased critical power phenomenon. Referring to FIG. 4A, an I shaped tab 109 having tabs 110 at the upper portion and tabs 112 is shown in the planar mode before twisting. FIG. 4B shows this construction in the twisted configuration. FIG. 4C shows the swirl vane incorporated to ferrules at their respective upper and lower ends. In this configuration, the main portion of the tab 109 deflects water towards the rods of the spacer while vapor is allowed to continue upwardly. More importantly, this spacer when incorporated to spacers S7, S6 and S5 of FIG. 3A or spacers S8, S7, S6 or S5 of FIGS. 3B-3F enables fuel bundles having part length rods to realize improved critical power. It is important to note a distinction. FIG. 3A insofar as it discloses ordinary spacers in combination with part length rods is prior art. However, when spacer having swirl vanes are added in addition to a fuel bundle having part length rods, the improved critical power limitations of this invention are realized. It is not necessary that the swirl vanes extend the entire length of the spacer. Specifically FIG. 5A illustrates a swirl vane end tab 132 before twisting. This swirl vane end tab 132 is show twisted and attached to the ferrule spacer construction illustrated in side elevation and plan respectively in FIGS. 5B and 5C. Attachment occurs at tabs 132 to the sides of the ferrules F so that turbulence imparting protrusion occurs above the spacer S. Other constructions can be utilized. Referring to FIG. 6A, a tab 140 having depending arms 142 is shown before twisting. In respective FIGS. 6B and 6C, attachment of the tabs occurs to the ferrules F with the full length of the arms 142 effecting secure fastening of the arms to the ferrules F. Finally, referring to FIG. 7A, a swirl vane 139 is shown in the untwisted state. Referring to FIG. 7B, the respective swirl vanes 139 have all been twisted. Tabs 140 are then ready for attachment to a ferrule spacer. Referring to FIGS. 7C and 7D attachment to the respective ferrules can be seen. Referring to FIG. 7C, an important detail can be noted. It is important that continuous web 142 not interfere with the spacing or pitch at the bottom of the spacer. Such interference could seriously alter the side-by-side spacing of the ferrules F. Accordingly, the tabs 139 have a length so as to dispose the continuous web 142 below the side-by-side ferrules F. As has been set forth above, other expedients associated with the spacers can be utilized to realize increased pressure drop. For example, in FIG. 8, a spacer of increased vertical height is utilized. Additionally, spacers having metallic constructions from thicker metallic sheets may be utilized. All that is required is to recapture at least some of the pressure drop achieved by the insertion of the part length rods. Regarding the extent of this recapture of pressure drop, we prefer to recapture less than all of the pressure drop realized. Accordingly, this leaves the upper two phase region of the fuel bundle with less pressure drop than the same bundle would have had with only full length rods. It is important to note that we use the increased spacer pitch or the swirl vanes attached to the spacer in combination with the two phase flow at the top of the fuel bundle. We rely on the effect of the spacer co-acting with the flow after it has passed through the spacer. This "downstream flow" occurs upwardly from the spacers after the two phase flow has passed over one of the spacers. This effect is important with respect to spacers S7 (FIGS. 3B-3F), spacer S.sub.6 and spacer S5. The top most spacer, spacer S7 in FIG. 3A and spacer S8 in FIGS. 3B-3F is an exception to this flow principle. It is not required that the top most spacer S7 in FIG. 3A or spacer S8 in FIG. 3B-3F be either a ferrule type spacer or have swirl vanes attached. In most fuel loadings, the kilowatt output per foot above the top most spacer is not at a level where transition boiling leading to adverse critical power ratios can occur. Consequently, an inconel spacer having low pressure drop with higher neutron absorption can be successfully used at this location. This upper spacer need not incorporate the increased spacer pitch or the disclosed swirl vanes. It will be apparent that this invention will admit of modification. It further will be appreciated that the decreased spacer pitch above the termination point of the partial length rods, is a major characteristic of this invention. Referring to FIG. 9, a fuel bundle B is illustrated. Bundle B includes a lower tie plate L, an upper tie plate U and a 9-by-9 matrix of discrete fuel rods F. A channel C surrounds the respective fuel rods and extends from the lower tie plate L to the upper tie plate U. Lower tie plate L supports the fuel rods F in a side-by-side matrix; upper tie plate U assures that the fuel rods are maintained in vertically upstanding relation. The fuel rods extend over a distance of approximately 160 inches and are flexible. This being the case, a group of spacers (typically in the order of 7) maintain the side-by-side relationship of the fuel rods F. In FIG. 9 spacers S.sub.1, S.sub.2 B and S.sub.5 illustrate three of the normally seven evenly placed spacers extending along the length of the fuel bundle B. Operation of the fuel bundle can be summarized. Typically, water moderator enters through lower tie plate L at defined apertures between the matrix of fuel rods F. The water flow is confined by channel C to flow outwardly through upper tie plate U. As the water moderator passes upwardly through the fuel bundle, steam is generated in increasingly higher fractions. Finally, at the top of the fuel bundle and up and through upper tie plate U, the discharge of water and steam occurs. Fuel bundle B contains part-length rods P. Such part-length rods P are disclosed and claimed in Dix, et al. U.S. Pat. No. 5,112,570 entitled TWO PHASE PRESSURE DROP REDUCTION BWR ASSEMBLY DESIGN issued May 12, 1992, (formerly U.S. patent application Ser. No. 07/176,975 filed Apr. 4, 1988). It will be noted that the two partial length rods P illustrated are spaced apart. Additionally, and overlying the part-length rods, there is defined an open spatial interval in the fuel bundle which interval is designated 114. As set forth in this original disclosure, these disbursed flow channels realize the natural tendency of the vapor phase of the two-phase mixture to migrate or drift towards the low resistance flow paths formed at the void volumes 114. It has been found that such disbursed flow paths are favorable to provide an improved fuel to moderator ratio in the upper two phase region of the bundle as well as to provide a low pressure drop path for the venting of steam which imparts combined nuclear, stability and thermal hydraulic advantages. At the end of each partial length rod P, I illustrate a separation device D. Generally stated, the purpose of the separation devices D as set forth in this specification is to separate water from the volumes 114 which may either be entered into or be entrained into the upwardly venting steam within volumes 114. This enhances the natural tendency for steam to flow in these volumes such that even better steam venting benefits can be achieved without the part length rods being spaced apart. Summarizing the remainder of the specification is beneficial at this juncture. Specifically, FIGS. 10, 11, and 12 disclose various separation devices which may be placed at the end of individual fuel rods. FIGS. 13, 14, 15, 16, and 17 disclose separation devices mounted to spacers. FIGS. 18, 19, and 20 disclose separation devices which can also be mounted to spacers, but preferably pass through the spacers and are suspended form the upper tie plate. FIG. 13 shows a combination of a separation device mounted at the end of a part-length fuel rod as well as a separation device attached to a spacer. FIG. 18 discloses a separation device combined with and extending continuously from the end of a part length rod through overlying spacers. it will be understood that more than one such combined device can be placed in the fuel assembly. FIGS. 16, 17, 19, 20, 21, 22, and 23 disclose arrays of adjacent part length rods with overlying separation devices. Such part length rod arrays can be distributed in various arrangements within the fuel assembly. FIGS. 19, 20, 21, and 22 disclose these separation devices extending through two or more spacers. These extended devices can pass through and be suspended from the upper tie plate to maximize steam venting and allow for top removal of the devices. FIGS. 22, 23, and 24 disclose devices to incorporate water rods within or adjacent to the steam vent volume to improve moderator distribution within the fuel assembly. With reference to FIGS. 10, 11, and 12, the reader will understand that the partial length rod P is the only such rod shown. It will be understood that any one or more of the partial length rods P could be placed in the rod array as illustrated in FIG. 13. In FIG. 10 the partial length rod P has at the end thereof an outwardly flaring bell-shaped cone 116. The purpose of the cone 116 is to divert upwardly flowing water outwardly and away from volume 114 overlying the part-length rod P; such deflection is illustrated at arrow 118. At the same time, steam 120, having a lighter mass, can divert its flow into the volume 114 overlying the part-length rod. Referring to FIG. 11, part-length rod P has attached to the end thereof a swirl vane 120 the twist here being oriented over 180.degree. in the counterclockwise direction as the band 120 extends upwardly from the end of the part-length rod 121 into the volume 114 overlying the part-length rod. The function of band 120 is easily understood. It imparts to dense water particles an outward centrifugal vector; steam being of lighter mass continues into the upward volume 114. Finally, and referring to FIG. 12, part-length rod P is shown with an array of outwardly deflecting tabs 125. Outwardly deflecting tabs 125 have the function of deflecting outwardly the dense water and permitting steam to continue upwardly in an uninterrupted path. At this point the reader should understand that many other separation devices at the end of the part-length rods can be utilized. All that is required is that the devices be capable of deflecting outwardly the denser water flow while permitting steam to continue vertically upwardly. Referring to the view of FIG. 13, a part-length rod P termination shortly above a spacer S.sub.5 is shown at a section of a fuel bundle similar to that illustrated in FIG. 1. The particular separation device D utilized is similar to those separation devices illustrated in FIGS. 9 and 11. FIG. 13 shows an additional aspect of this invention. Specifically, spacer S.sub.6 is shown supporting a second separation device D', device D' taking the form of a downwardly disposed cone 30. Referring to cone 130, it can be seen that the apex of the cone is disposed towards the partial length rod P; the truncated base of the cone is mounted upwardly into spacer S.sub.6 which is the spacer immediately overlying the part-length rod. The function of the cone is easy to understand. Heavier liquid particles are directed outwardly to the adjacent fuel rods F. Steam continues upwardly in the volume 114 overlying the part-length rod P. Referring to FIGS. 14 and 15, the disposition of an alternate separation device D' at the spacer S.sub.6 is illustrated. In FIG. 6 the matrix defined by the spacer S.sub.6 maintains a swirl vane 140. Like the separation device of FIG. 3, swirl vane 140 is twisted over 180.degree. and serves to centrifugally separate water from the volume 114 overlying part-length rod P. It will be understood that separation device D' is effective in separating out water that may be entrained into the steam vent of volume between the part-length rod P and spacer S.sub.6. The construction of FIG. 15 is similar, the only exception being that the swirl vane 142 is of a larger width occupying substantially the full volume within the spacer S.sub.6 between the fuel rods F. FIG. 16 illustrates a similar construction, with an array of adjacent part length rods P terminating below spacer S. Spacer S supports an array of overlying swirl vanes 150 at a distance above the ends of part length rods P. As the reader will understand, the disclosed side elevation only illustrates three part length rods and associated swirl vanes. More could be used. For example, a 3 by 3 matrix adjacent of part length rods could be used. FIG. 17 illustrates a similar construction to FIG. 16. Here a larger diameter swirl vane 152 attached to spacers overlies an array of adjacent part length rods P. The part length rods P are configured typically in a 3 by 3 square pattern. More could be used. FIG. 18 illustrates an extended swirl vane 160 attached to the end of a part length rod. Part length rod P and swirl vane 160 form a unitary structure. This rod P and swirl vane 160 mount in the same manner as the side-by-side full length fuel rod F. Consequently, part length rod P can be removed by grasping swirl vane 160 or any fixture attached to swirl vane 160 for that purpose. The swirl vane can also be constructed with two crossed (cruciform sectioned) metal bands to increase strength for the swirl vane of this design The part length rod and swirl vane are here shown extending between two spacers S.sub.1 and S.sub.2. FIG. 19 illustrates a single large swirl vane 162 overlying a number of adjacent part length rods (for example a 3 by 3 matrix of part length rods P). This single large swirl vane 162 is attached between spacers S.sub.1 and upper tie plate U. Alternately, provision can be made for attachment of the large swirl vane between two adjacent spacers (See FIG. 18). Provision of an opening for this device to pass through the upper tie plate U maximizes the steam venting effectiveness of this design. Mounting the device to the upper tie plate allows for removal of the device from the top, thus providing access to the part length rods underlying the device. The construction of FIG. 20 is similar, except the single large swirl vane device is replaced with a unitized matrix of smaller swirl vanes. The matrix of swirl vanes here shown and here illustrated is 3 by 3. This unitized matrix is illustrated with surrounding bands 168 to provide positioning at the fuel assembly spacers S.sub.1. This device preferably passes through and is suspended from the upper tie plate U. The construction of FIG. 21 is similar, except the underlying part length rods P are of unequal height. Consequently, the overlying unitized matrix of swirl vanes 165, 165' is of unequal length. The large steam vent volume may reduce local neutron moderation. Therefore, it may be necessary to improve moderator distribution by incorporating additional water into the central portion of the fuel assembly. FIGS. 22, 23, and 24 disclose devices wherein water rods are incorporated to the swirl vane structure of this invention. FIG. 22 illustrates an alternate construction for the large swirl vane of FIG. 11, wherein a central water rod W is placed integral with the swirl vane 170. The underlying central part length rod is removed to allow for downward extension of the water rod W. The water rod W is shown the same diameter of the fuel rods F and part length rods P; other so-called large water rods W may be used where the diameter exceeds the diameter of the fuel rods F. FIG. 23 shows similar construction for a water rod integral within a unitized swirl vane matrix 172. FIG. 24 illustrates a representative fuel assembly configuration using a swirl vane matrix 176 with individual swirl vanes 174 such as illustrated in FIG. 20 or FIG. 21. Water rods W are placed adjacent to the removable swirl vane matrix 176. Such placement of water rods also allows for standard axial positioning of the fuel assembly spacers S.sub.1 and S.sub.2 (See FIG. 23). The reader will understand that in my description of separation devices D', I contemplate any type of separation device overlying the part-length rod, this separation device acting to eject either entering or entrained water from the void volume overlying the end of the part-length rod.
	abstract	Disclosed is an operation for an optical system which achieves observation of focused ion beam processing equivalent to that in a case wherein a sample stage is tilted mechanically. In a focused ion beam optical system, an aperture, a tilting deflector, a beam scanner, and an objective lens are controlled so as to irradiate an ion beam tilted to the optical axis of the optical system, thereby achieving thin film processing and a cross section processing without accompanying adjustment and operation for a sample stage. The thin film processing and the cross section processing with a focused ion beam can be automated, and yield can be improved. For example, by applying the present invention to a cross section monitor to detect an end point, the cross section processing can be easily automated.
041995392	description	DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a hydraulic dual platen press is depicted. The press includes upper and lower hydraulic actuators 1 and 2 which control the movement of upper and lower platens 3 and 4, respectively. In the area between the upper and lower platens 3 and 4 there is a die table 6 having a plurality of die cavities 7 therein. The upper and lower platens 3 and 4 each carry a plurality of cylindrical rams 8 and 9 each of which is associated with a single die cavity. Hydraulically actuated platens 3 and 4 move the rams 8 and 9 in and out of the die cavities in a vertical direction to effect compaction of the UO.sub.2 powder deposited therein and ejection of the compacted nuclear fuel pellet thereby formed. The normal sequence of operations starts with the lower platen 4 positioned so that the lower rams 9 are even with the top surface 10 of the die table 6. The lower platen is then moved down and the die cavities are filled with the desired depth of UO.sub.2 powder. The upper platen 3 then moves down so that the upper rams 8 are even with the top surface 10 of the die table 6. The upper and lower platens then move together in exactly equal amounts to effect compaction of the UO.sub.2 powder. The upper and lower platens then move upwardly to eject the compacted nuclear fuel pellets from the top of the die cavities. During the ejection portion of the press cycle the rams 8 associated with upper platen 3 remain in contact with the compacted nuclear fuel pellets for the purpose of exerting a hold-down force on the pellets. Spring pressure or pressure generated in the upper hydraulic actuator 1 may be used to provide this ejection hold-down force. When spring pressure is used to generate ejection hold-down force the press is normally referred to as being in a standard ejection cycle. In the standard ejection cycle, immediately upon the completion of the compaction portion of the press cycle hydraulic pressure in the upper hydraulic actuator 1 is released allowing a spring 11 to establish a gap 12. As the ejection cycle proceeds the lower ram pushes the fuel pellet out of the top of the die cavity and with the gap 12 established the spring 11 provides a relatively constant hold-down force. Hold-down force may be varied in the standard ejection cycle for different press set-ups by adjusting the spring gap 12 to change the spring preload or by replacing the spring 11 with other springs having different spring constants. Hold-down forces generated by hydraulic pressure are generally used when the pressing operation requires greater hold-down forces than may be generated by spring pressure. Hydraulic hold-down force is generated by manipulation of the pressures in the chambers 13 and 14 above and below the piston 15 of the power hydraulic actuator 1. The pressure above the piston is generally referred to as the back pressure and the pressure below the piston is generally referred to as the weight control pressure. Hydraulic hold-down force may be generated by the use of back pressure only or by a combination of back pressure and weight control pressure which is established at the beginning of the ejection cycle. When hold-down force is hydraulically actuated the spring gap 12 is closed. According to the invention, a method for monitoring, analyzing and controlling the operation of the dual platen press just described is provided. The method is comprised of the following steps. The displacements of the upper and lower platens 3 and 4 are measured and optical, mechanical or electrical signals representative of these displacements are created. These signals are then imposed on orthogonal axes, such that the displacements of the press platens simultaneously control the motion of a point which traces a plane curve, which in the present case is a lissajous figure. Lissajous figures are generally known as plane curves traced by a point which executes two independent harmonic motions in orthogonal directions. The lissajous figure constructed according to the present method may be used by a press operator directly or in combination with a second lissajous figure representative of the desired platen displacements. In the former case the operator uses the lissajous figure directly as a basis for monitoring and analyzing the operation of the press. In the latter case the operator may use the invention to monitor and analyze the operation of the press by superimposing the first lissajous figure, constructed from the actual platen displacements, on the second lissajous figure which serves as a standard for the type of press operation being run, deviations between the first and second lissajous figures indicating deviations from the desired press operation. Whether used in combination with a second lissajous figure or not, the first lissajous figure provides the press operator with an important diagnostic tool for monitoring and analyzing press operations. The slope of various portions of the first lissajous figure indicates the relative velocity of the press platens during that portion of the press cycle being examined. The displacement of the press platens may be measured directly from various portions of the first lissajous figure and the relative displacement of the platens is provided by a comparison of these portions. The lissajous figures constructed according to this method will thus aid the press operator in monitoring and analyzing press operations and adjusting the various pressing parameters for duplicating a good press set-up, or determining a good press set-up for the first time. The invention also provides a method of eliminating the various microswitches which are generally used to detect platen displacements and initiate and terminate various portions of the press cycle. This function is carried out by providing for the detection of preselected portions of the first lissajous figure, and thereby triggering subsequent press operations. Referring now mainly to FIGS. 2(a) and 2(b), a typical pressing cycle for a dual platen press, used in the manufacture of nuclear fuel pellets, will be described in in detail. FIG. 2(a) represents the displacement versus time graph for the upper platen and FIG. 2(b) represents the displacement versus time graph for the lower platen. Line segments on each of the graphs are designated with capital letters. With the platens in their initial positions, as indicated by line segments A and G, both platens are stationary while UO.sub.2 powder is deposited on the die table above the die cavities. In position A, the upper platen 3 and rams 8 are completely withdrawn from the die cavity. In position G, the lower platen 4 is positioned so that the rams 9 are flush with the top surface 10 of the die table 6. Next, the lower platen moves down, as indicated by line segment H, and UO.sub.2 powder enters the die cavities. The lower platen remains stationary, as indicated by line segment I, while the upper platen moves down, first rapidly, as indicated by line segment B, and then more slowly, as indicated by line segment B', as the rams 8 approach the top surface 10 of the die table 6. At the end of line segment B the rams 8 are even with the top surface 10. Next, the two platens move toward one another in exactly equal amounts at identical speeds, indicated by line segments C and J. This compresses the powder deposited in the die cavities to form the fuel pellets. During the next portion of the press cycle, the lower platen continues to move up while the upper platen reverses direction so that both platens move up with identical motions, as indicated by line segments D and K. This is normally referred to as the ejection portion of the press cycle. The upper platen then gradually lifts off the pellets, as indicated by line segment E, and then retracts more rapidly, as indicated by line segment E'; while the lower platen reaches the top of the die table and stops its motion, as indicated by line segment L. This completes the press cycle and both platens are now in position for initiating the next press cycle. A simple mechanical and optical device for constructing a lissajous figure corresponding to the two platen displacements just described is illustrated in FIGS. 1 and 3. The device comprises two plates 16 and 17 which are mounted on the side of the press overlapping one another. Plate 16 is connected to the upper platen 3 by member 18 while plate 17 is connected to the lower platen 4 by member 19. The plates have diagonal slots 20 and 21 arranged such that the two slots are at right angles to one another and overlap each other. Normally, each slot is at an angle of 45.degree. to the vertical. In one embodiment of the invention, a light source 22 is placed behind the plates to provide a beam of light which penetrates the intersection 23 of the slots 20 and 21. In other embodiments of the invention a pen or a heat marker may be mounted at the intersection of the slots. As the platens move through the cycle illustrated in FIGS. 2(a) and 2(b), the intersection 23 of the two slots 20 and 21 moves through a definite pattern. This pattern is shown in FIG. 4 and is the lissajous figure of the press operation illustrated in FIGS. 2(a) and 2(b). In FIG. 4, the same nomenclature as that employed to identify the line segments of FIGS. 2(a) and 2(b) is combined to indicate which portions of the line segments of FIGS. 2(a) and 2(b) correspond to each portion of the lissajous figure. For example, portion AH is created with the upper platen stationary while the lower platen moves down such that the intersection of the slots describes a straight line at an angle of 45.degree. to the vertical. Another example is the horizontal portion marked CJ. Here the two platens and thus the two plates move in opposite directions by exactly equal amounts. This causes the intersection of the slots to move horizontally from right to left. If the platens do not move in a synchronous manner, at equal velocities, the slope of the line CJ will vary. A further example is the portion DK where both platens move up in unison so that the intersection of the slots describes a line moving in the vertical direction. The gradual lift off the upper ram while the lower ram remains stationary can be seen by the diagonal line segments EL and E'L. Thus, a complete lissajous figure is described which is representative of the movements and relative velocity of the press platens. For monitoring purposes a transparent plate 25 having the desired lissajous figure 26 enscribed thereon may be mounted over the two plates 16 and 17. Then as the two plates 16 and 17 move through a press cycle, the operator will be assured of the correct operation of the press as long as the light beam exiting the intersection 23 of the two slots travels along the lissajous figure 26 enscribed on the transparent plate 25. In embodiments of the invention having a pen or a heat marker mounted at the intersection of the slots a suitable drawing surface is provided upon which the lissajous figure resulting from the operation of the press may be enscribed. If a moving light beam is used to form the lissajous figure, means for detecting preseleted portions of the lissajous figure and triggering subsequent press operations therefrom may be provided. FIG. 5 illustrates a simple light actuated tripping circuit which may be employed with the embodiment of the invention illustrated in FIG. 1. This type of circuit is well known to those skilled in the electrical arts and may be broadly described as a Schmidt trigger. The collector of photosensitive transistor 30 is connected to a biasing voltage V.sub.cc. The emitter of photosensitive transistor 30 is connected to the base of an output transistor 31 and to ground through a resistor 33. The collector of output transistor 31 is connected to an output trigger line 38 and to biasing voltage V.sub.cc through resistor 32. The emitter of output transistor 31 is connected to ground. The base of transistor 30 is arranged to receive a light beam, designated by 34, from the light source 22. In a specific example of a circuit of the type shown in FIG. 5 which is suitable for use with the present invention, the phototransistor 30 is a Fairchild FPT131, the output transistor 31 is any 2N222 transistor and resistors 32 and 33 are 3.3k ohms and 1k ohms, respectively. In the operation of the circuit light beam 34 impinging upon the face of the phototransistor 30 causes the transistor 30 to become conductive, providing a voltage to the base of output transistor 31. The output transistor 31 now becomes conductive thereby providing an output trigger for line 38. The output trigger line 38 is connected in any suitable manner to initiate and terminate operations of the press. Referring now again to FIG. 3, normally a plurality of such photoelectric tripping circuits will be provided having photosensitive transistors 30 mounted on the overlying plate 25 at points 40 through 46. The phototransistors are arranged to detect the completion of preselected portions of the lissajous figure constructed, as previously described, by movement of the intersection 23 of the slots 20 and 21. When light from the light beam tracing the lissajous figure impinges the face of one of the phototransistors mounted at points 40 through 46 on plate 25 the output of the circuit illustrated in FIG. 5 is used to trigger subsequent portions of the pressing cycle. The microswitches now ordinarily used to terminate and initiate various portions of the press cycle will thus be eliminated. Modifications may be made in the embodiment just described without departing from the spirit of the invention. For example, the plates 16 and 17 may be connected to the rams mechanically or hydraulically. A hydraulic link between the device just described and the press platens would allow the device to be remotely placed from the press. It may be desirable to utilize only a portion of the lissajous figure to simply obtain the most important sections corresponding to the compaction and ejection portions of the press cycle, respectively. Thus, a device which is actuated only during those sections may be provided. Referring now to FIG. 6, an electrical embodiment of the device is illustrated. The dual platen press 50 depicted in FIG. 6 is the same type of press shown in FIG. 1 and like components are given the same identifying numbers. In the electrical embodiment linear variable differential transformers (LVDT's) 51 and 52 are mounted to the upper and lower platens 3 and 4, respectively. LVDT units are well known to those skilled in the electrical arts and the units used here are used to translate linear motion into linear DC electrical signals. The LVDT units 51 and 52 are powered by power supplies 53 and 54, respectively. The output signals V.sub.1 and V.sub.2 from the LVDT units 51 and 52 are supplied to the X and Y terminals 57 and 58 of a recorder 55 for the purpose of producing a lissajous figure 56 on graph paper 59 representative of the operation of the press. The recorder 55 may be any of a number of readily available conventional electrical recording devices. For example, the recorder may also be a cathode ray tube and the signals provided to the terminals 57 and 58 may be employed to drive the X and Y deflection circuits of the cathode ray tube (for example see FIG. 7). In one specific example of this electrical embodiment, the LVDT unit 51 is a Shaevitz unit, number 5000 DC-B and LVDT unit 52 is Shaevitz unit, number 2000 DC-B. These LVDT units translate linear motion into .+-.10 VDC linear electrical signals. The power supplies 53 and 54 are Shaevitz, number PSM 120, .+-.15 VDC power supplies. The recorder 55 is a Hewlett Packard Model 7035 B X-Y recorder. Referring now to FIG. 7, an alternate arrangement for displaying a lissajous figure representative of the operation of the press and for detecting the completion of preselected portions of the lissajous figure is illustrated. FIG. 7 shows cathode ray tubes (CRT's) 70 and 71 connected to receive electrical signals V.sub.1 and V.sub.2 from LVDT units 51 and 52, respectively. The CRT 71 provides a visual display which may be used by the operator to monitor and analyze press operations and/or for a comparison with a standard lissajous figure representing the desired platen displacements. The CRT 70 is provided as a means for detecting the completion of preselected portions of the lissajous figure constructed from the actual platen displacements. The CRT 70 is covered with a mask 72 attached to the front of the CRT by the screws 73 or the like. The mask 72 has a plurality of phototransistors 74 mounted thereon such that the phototransistors receive light from the lissajous figure traced by the CRT 70. Each of the phototransistors 74 is actually part of a photoelectric tripping circuit such as the one in FIG. 5 so that light impinging the faces of the phototransistors controls an output trigger which may be used to terminate and initiate portions of the pressing cycle. FIG. 8 illustrates a simple voltage comparison circuit which will generate an 8-bit digital control word from LVDT signals V.sub.1 and V.sub.2. This type of circuit is well known to those skilled in the electrical arts. The signals from the LVDT units 51 and 52 are inputed to 8-bit analogue-to-digital converters 60 and 61, respectively, where the signals V.sub.1 and V.sub.2 are converted into a binary code. Analogue-to-digital converters 60 and 61 are connected to read only memories 62 and 63 by a conventional arrangement which accounts for most significant and least significant bits. The output of the read only memories 62 and 63 is combined to provide an 8-bit control word which is used to control subsequent press operations. The analogue-to-digital converters 60 and 61, and the read only memories 62 and 63 are of a type readily available commercially. By way of example analogue-digital-converters sold by Analog Devices, Inc., part number ADC 8ZM may be used at 60 and 61. Read only memories suitable for 62 and 63 are sold by Intel, Inc., part number 2316A ROM. In the operation of the circuit analogue signals V.sub.1 and V.sub.2 from LVDT units 51 and 52 are converted into an 8-bit digital control word which may be used to directly terminate and initiate portions of the press cycle, or inputed to a digital processor to produce a sequence of programmed responses. The mechanically actuated microswitches which are ordinarily used to trigger subsequent portions of the press cycle may thus be eliminated. FIGS. 9(a) through 9(i) are examples of various lissajous figures obtained from the devices described above. These figures are employed in the following description to illustrate the manner in which the lissajous figures constructed in accordance with this invention may be analyzed in terms of press operations. Various portions of the press cycle are labelled with the nomenclature of FIG. 4 to identify the sequence of press operations. The lissajous figures of FIGS. 4 and 9 differ only in the orientation of the orthogonal axes upon which the platen displacements are imposed. Line segment AH indicates the lowering of the lower platen to fill the die cavity; BI and B'I indicate the downward movement of the upper platen; CJ represents the compaction of the powder in the die cavity; DK represents the ejection of the compacted nuclear fuel pellet; and line segments EL and E'L represent the raising of the upper platen at the end of the press cycle. FIGS. 9(a) through 9(i) each represent a different press set-up for the manufacture of 0.5 inch high nuclear fuel pellets from a depth of fill in the die cavity of 1.0 inch. FIG. 9(a) illustrates a lissajous figure observed from a press set-up that was termed "good" by production personnel skilled in setting up dual platen hydraulic pressed for the manufacture of nuclear fuel pellets. In FIG. 9(a) the solid curve 80 represents the lissajous figure constructed from the actual platen displacements. Curve 80 is shown superimposed on the ideal lissajous figure 81 (arrows and broken lines) to show deviations in the operation of the press. A standard ejection cycle was used in this pressing cycle, meaning that hold-down force exerted by the upper ram during the ejection portion of the press cycle was generated by spring pressure rather than hydraulic pressure. In this press operation the ideal lissajous figure indicates that the Y component of the ejection portion of the curve should be three times greater than the Y component of the compaction portion of the durve, assuming equal compaction from the upper and lower platens. This is obvious from a dimensional analysis of the compaction operation. With a 1.0 depth to fill, to obtain a 0.5 inch pellet both rams, and thus both platens, must move 0.25 inches during the compaction portion of the press cycle. This puts the bottom of the pellet 0.75 inches from the top of the die table, and both the upper and lower rams must move upward 0.75 inches to complete ejection of the pellet. The ratio of the Y components of the ejection and compaction curves is therefore 0.75:0.25, or 3:1. A comparison of the lissajous figure constructed in FIG. 9(a) with the reference marks (X and 2X) in FIG. 9(a) shows that the ratio is less than 3:1 indicating more compaction by the lower platen than is desirable despite the fact that this was thought to be a "good" press set-up. The basically 45.degree. slope of the ejection portion DK and compaction portion CJ of the lissajous figure of FIG. 9(a) indicates that the speed of the upper and lower platens was identical during the compaction and ejection portions of the press cycle. The small amount of horizontal travel, indicated by the numeral 82, at the initiation of the ejection portion of the press cycle indicates that the upper ram moved away from the pellet at the beginning of the ejection cycle. The velocity of the upper platen exceeded that of the lower platen at this point due to spring pressure relaxing during the establishment of the spring gap and the lower ram overcoming the initial friction of the pellet in the die cavity. The change in slope at the end of the ejection cycle, indicated by the numeral 83, indicates that the lower platen speed increased during ejection which probably caused the spring gap to close at the end of the ejection cycle. The fact that a press set-up which produced a lissajous figure having these deviations was termed "good" by production personnel skilled in the art of setting-up dual platen presses for the manufacture of nuclear fuel, but not having the benefit of the present invention, is indicative of the improved analysis of the pressing operation made possible by the present invention. FIG. 9(b) illustrates a lissajous figure representing a press cycle with overpressing of the upper platen. A standard ejection cycle is used again. The ratio of the Y components of the ejection and compaction portions of the curve (approximately 9:1) indicates that the upper platen is pressing approximately 3 times as much as the lower platen. This is due to the lower platen being actuated too late during the compaction portion of the press cycle since the basically 45.degree. slopes of both the ejection portion DK and compaction portion CJ of the lissajous figure indicates that platen speeds were matched. The overall shape of the ejection portion of the lissajous figure is identical to that of FIG. 9(a) since only the pressing location in the die was changed. FIG. 9(c) illustrates a lissajous figure for a press cycle with overpressing of the lower platen and a standard ejection cycle. The ratio of the Y components of the ejection portion DK and compaction portions CJ of the lissajous figure (1.6:1) indicates overpressing with the lower platen. Overpressing with the lower platen is an infrequent problem which is easily diagnosed by the operator because of the visible sign of powder being pushed out of the top of the die cavity at the beginning of the compaction portion of the cycle before the upper ram closes off the top of the die cavity. FIG. 9(d) illustrates a lissajous figure for a press cycle with the lower platen speed decreased and a standard ejection cycle. The slopes of both the compaction portion CJ and ejection portion DK of the lissajous figure are less than 45.degree. to the horizontal, indicating that the upper platen speed was greater than that of the lower platen. The ratio of the Y components of the ejection and compaction portions of the lissajous figure indicates that compaction by both platens was equal but at different speeds. The ejection speed of the upper platen exceeded the lower platen speed sufficiently to totally remove hold-down pressure during ejection. The change in slope during compaction indicates upper platen deceleration upon compaction pressure build-up since its speed is initially greater than that of the lower platen. FIG. 9(e) illustrates a lissajous figure for a press operation using hydraulic hold-down force. In this press operation hold-down force was only generated with back pressure. No weight control pressure was established. The lissajous figure indicates equal compaction by upper and lower platens but initially at different speeds (the lower platen is slower). The horizontal portion of lissajous figure normally present (see, for example, 82 in FIG. 9(a)) at the beginning of ejection portion of the lissajous figure is eliminated indicating that the upper ram and lower ram are simultaneously withdrawn. The non-linear slope of the ejection portion of the lissajous figure is believed to indicate pressure build-up on the bottom side of the piston in the upper hydraulic actuator. FIG. 9(f) illustrates a lissajous figure for a press operation using hydraulic hold-down force generated from manipulation of both the weight control and back pressures. The curve indicates equal compaction by the upper and lower platens showing that compaction is unaffected by the weight control pressure. The weight control pressure was established at the start of the ejection portion of the press cycle which caused the upper platen to withdraw at a faster speed than the lower platen on ejection. This is indicated by an initial ejection slope less than 45.degree. to the horizontal. This is believed to occur because only a few microseconds are available in which to decompress, establish the weight control pressure and then establish the back pressure. The initially faster speed of the upper platen results from a failure to establish sufficient back pressure at the start of the ejection cycle. This press operation was run again in FIG. 9(g) with dwell. Dwelling of the rams at the point of maximum compression is used when the powder being pressed has poor compaction properties. A comparison of the lissajous figures of FIGS. 9(g) and 9(f), obtained with and without dwell, indicates that the normal operation of the press is unaffected by dwell. FIGS. 9(h) and 9(i) illustrate lissajous figures for a press operations using hydraulic hold-down force generated with weight control and back pressure. FIG. 9(i) represents a press cycle that yields acceptable pellets. FIG. 9(h) shows the result of increasing the back pressure until the pellet is crushed. The curves show equal compaction by the upper and lower platens. Pellet crushing during the ejection cycle is indicated by the vertical slope, identified by the numeral 84, at the end of the ejection portion DK of the lissajous figure of FIG. 9(h). Back pressure increase is evidenced by a line 85 which tends to exceed a 45.degree. angle just prior to the crushing point. Back pressure increase is also evidenced in the comparison of the ejection portions of the lissajous figures of FIGS. 9(h) and 9(i). Less horizontal travel (less upper platen speed) verifies increased back pressure which prevents the upper platen from accelerating ahead of the lower ram. The analysis of the illustrative lissajous figures shown in FIG. 9 in terms of press operations makes it clear that the lissajous figures constructed according to the invention provide the operator of a dual platen press with an excellent diagnostic tool, as well as providing a method for monitoring the operation of the press. With this new tool for analyzing press operations and relating them to fuel pellet quality it is now possible to more quickly identify the correct pressing parameters for a given type of UO.sub.2 powder. Duplicating a good press set-up for a UO.sub.2 powder having known pressing requirements, and thus a known lissajous figure, becomes a matter of adjusting the press so that it duplicates the correct lissajous figure. The continued operation of the press with the desired pressing parameters is ensured as long as the lissajous figures constructed from the platen displacements correspond to the lissajous figure developed from the desired platen displacements. While the invention has particular advantages when applied to a press used in the manufacture of nuclear fuel pellets, it should be understood that the invention may be advantageously employed to monitor the operation, analyze the pressing cycle and control the operation of any type of manufacturing operation in which a dual platen press is used. Other modifications of the invention will occur to those skilled in the art and it is desired to cover in the appended claims all of such modifications as fall within the scope of the invention.
044329318	summary	BACKGROUND OF THE INVENTION The present invention relates to a remote visual inspection system for certain areas of vessels which are not accessible for inspection by personnel. It particularly relates to the inspection of a storage arrangement wherein there is a primary vessel for containing a fluid and an outer vessel, generally referred to as the containment vessel, which surrounds the primary vessel to prevent loss of fluid in the event of a rupture or leak in the primary vessel. There are many reasons why a primary vessel containing a fluid would be contained within a secondary containment vessel. For example, if the fluid is hazardous or dangerous to the environment, the secondary vessel acts to catch and retain the fluid in the event of a leak. In addition, when the primary vessel contains a fluid which is at an extreme temperature, for example, either a cryogenic fluid or a high temperature fluid such as would be found in a nuclear reactor, the space between the primary and secondary vessels acts to provide insulation and minimize the loss of heat from the primary vessel to the environment. A nuclear reactor presents a particularly difficult inspection problem since the space between the two vessels is at a relatively high temperature, generally 200.degree. C. or more. In addition, the space between the primary and secondary vesels generally is maintained at a minimum. In the event of a rupture in the primary vessel, the fluid would drain into the area between the two vessels. This could create an extremely dangerous situation if the fluid level in the primary vessel became so low as to expose the reactor core. If the core were exposed, it would not receive sufficient convection coolant, with the result being fusion of the core. Thus, if the space between the two vessels is not maintained relatively small to prevent this possibility, the alternative is to maintain an extremely large inventory of coolant in the primary vessel. To ensure continued safe operation of, for example, a nuclear reactor, periodic inspection at least of the primary vessel outer wall is required. While various methods have been proposed for inspection of the interior of vessels, very few systems or methods are known for inspecting the narrow annulus that generally exists between a primary vessel and a containment vessel, particularly at the operating temperatures encountered in a nuclear reactor. In addition to being able to inspect the interior of such an annulus, it also is necessary to know at all times precisely where the visual inspection device is located in order to compare subsequent inspections with those made earlier when it was known that the structural integrity of the vessel was intact. Further, it generally is desired, particularly in the case of nuclear reactors, that there be no penetration in the containment vessel at any level below that of the uppermost portion of the reactor core, the reason for this being obvious in that any such penetration represents another potential failure point in the system. Accordingly, it is an object of the present invention to provide a system which permits precise location of a remote visual inspection device for examining the annular space between a primary vessel and a containment vessel. It is another object of the invention to provide a remote visual inspection system which can withstand exposure to an extreme range of temperatures. SUMMARY OF THE INVENTION In accordance with the present invention, there is provided a system for remote visual inspection of a structure comprising a primary vessel surrounded by a containment vessel. Broadly, the system comprises at least one, and preferably more than one, substantially rigid fixed conduit member which terminates at a first end adjacent an upper portion of the vessel and at its second end adjacent an area to be inspected. The conduit member is provided with at least one aperture adjacent the area to be inspected. The system further includes a housing containing a camera and a light source for insertion into the first end of the conduit member and means for maintaining or controlling the temperature of the camera in the housing. There is also provided a support means for the housing which includes at least a first hollow, flexible hose member having a first end connected to the housing and a second end terminating adjacent an upper portion of the vessels. The support means further includes an electrical conduit for supplying electrical power to the camera and light source, and transmitting signals received from the camera to a display means remote from the camera for receiving said signals. There also is provided a pressurizing means for introducing a fluid into the flexible hose member in an amount sufficient to provide a desired amount of rigidity to the hose member to facilitate pushing the housing and the hose member through the fixed rigid conduit member to a desired location. In accordance with certain preferred embodiments of the invention, the rigid fixed conduit member extends along the length of a weld seam in one of the vessels, generally the primary vessel and is provided with a plurality of closely spaced apertures adjacent the length of the weld seam. Generally, there is provided more than one fixed conduit member to permit inspection of all of the weld seams and any other areas of interest. In accordance with yet another embodiment, the flexible hose member and housing are provided with some positioning means for maintaining the housing substantially in the center of the conduit member. Preferably, the positioning means includes rollers positioned about the periphery of the housing and hose member which also act to minimize frictional forces as the housing is pushed into the rigid conduit member. In acordance with yet another embodiment of the invention the support means further includes a second hollow, flexible hose member, one of said hose members being located about the periphery of and coaxial with the other hollow, flexible hose member. The inner surface of one hose member and the outer surface of the other hose member define an annular space therebetween, the first and second hose members cooperating to provide a flow path for fluid from the pressure means to the housing and back to an upper portion of the vessels. The fluid is passed in heat exchange relationship with the camera and provides the means for controlling the temperature of the camera. Preferably, the fluid is an inert gas such as nitrogen, helium, argon, or carbon dioxide.
	abstract	An apparatus having an x-ray source and an x-ray detector configured to be rotated about a standing patient to capture and store a plurality of radiographic images of the patient during the rotation. A portable enclosure surrounds the source, the detector and the patient.
039430367	summary	The invention relates to a fast breeder nuclear reactor having fluid cooling, preferably liquid metal cooling and canless fuel elements in the fissionable fuel zone or core thereof. The breeder reactor differs from a normal or ordinary nuclear reactor in that the breeder reactor is constructed of at least two regions or zones which differ basically in their function. The core zone is arrayed with fissionable fuel elements in which there occurs a controlled chain reaction for splitting U.sub.235 or plutonium atoms, with the development of very great quantities of heat. A breeder material zone or breeder mantle is located outside the fissionable fuel core zone and has a construction similar to that of the core zone, but contains, however, in the elements thereof i.e. the breeder elements, no nuclear fuel but rather so-called breeder material such as U.sub.238. Due to neutron capture from the reactor core proper, the U.sub.238 atoms are transferred or transmuted into plutonium atoms and thereby into fissionable fuel. Heat production in this zone is relatively small compared to the heat produced in the nuclear fuel zone, and the differences with respect to the heat power per volume element are even greater. The same coolant such as, for example, steam (vapor), gas or primarily liquid metal like sodium, potassium, etc., is normally employed for cooling both zones. Since the efficiency of the transformation of the produced heat to electrical energy depends very greatly on the final temperature of the coolant, measures must be taken to have the outlet temperature of the coolant overall uniform i.e. over the entire cross section of the breeder reactor. To attain this objective, it has been proposed heretofore to surround the individual fuel elements and breeder material elements with a metallic mantle so that the inner space of the entire reactor is formed of a multiplicity of such coolant channels subdividing the flow. It is accordingly possible to so shape the core zone of the breeder reactor, wherein the fuel elements are disposed, that in addition to the reduction of the so-called void coefficients, the temperature release is the same from all of the fuel elements. In the breeder mantle, however, this uniformity of the thermal release is no longer present because the power output of the individual breeder elements is no longer constant with time but rather, in the course of the operating time increases in proportion to the growth of plutonium. The coolant throughput through this zone must therefore first be throttled so that the outlet temperature is virtually the same as that from the core zone. Moreover, the heretofore required throttling devices must be adjustable from the outside in order to do justice to the change in the power release due to the increasing plutonium production. Another possibility is to provide within the breeder material zone various regions with different coolant throughput and to transform the breeder material element continuously within these regions in accordance with the plutonium formation therein. This construction of the fuel and breeder material zones has the disadvantage that a considerably pressure difference occurs between the inner space of the fuel and breeder material elements, on the one hand, and the gap therebetween, on the other hand. Since there is virtually no flow in the gaps between the fuel elements, the foot thereof between the mantles, boxes or cases of these elements is at coolant outlet pressure. This pressure difference, which can be of the order of magnitude of 4 atmospheres absolute, for example, has an effect upon the fuel element mantle or casing, and these must therefore be given a suitable wall thickness in order to avoid mechanical deformations and bends or distortions. The additional structural material costs moreover impairs the breeding rate of the entire reactor; also the mechanical long-term characteristics of these casing or cans at the high neutron flux density are not to be overlooked. It should also be noted that in addition to the pressure-loading, a strong bending of the casing or can in the order of magnitude of centimeters occurs due to the radially decreasing irradiation intensity by fast neutrons and the threshold effect of the structural material required thereby. Mechanical prevention of such bending, for example by tension or clamping members, is impossible. The question was therefore than raised if it were possible to construct the fuel elements without any outer mantle or casing as for light water reactors i.e. as so-called open or canless fuel elements. No close approach could be made, however, to this idea because the disadvantages with respect to the efficiency that were associated therewith, no possibility of controlling the coolant flow, were too difficult to overcome. It is accordingly an object of the invention to provide a fast breeder reactor which avoids the foregoing disadvantages of the heretofore known devices of this general type. More specifically, it is a further object of my invention to provide a fast breeder reactor wherein a uniform outlet temperature of the coolant over the entire reactor cross section is afforded by employing canless fuel and breeder material elements. With the foregoing and other obejcts in view, I provide in accordance with my invention fluid-cooled fast breeder reactor comprising an outer cylindrical boundary wall, a plurality of fuel elements and breeder material elements of canless construction received within the boundary wall and being in an array therein forming a fissionable fuel zone and a breeder material zone coaxially surrounding the fissionable fuel zone, a coolant supply system for applying fluid coolant at uniform pressure to the entire cross section within the cylindrical boundary wall, and flow guide devices extending substantially horizontally and disposed one above the other within the breeder material zone which coaxially surrounds the fissionable fuel zone, the flow guide devices, respectively, being alternately elastically secured to the boundary wall and spaced by an annular gap therefrom. With this arrangement of guide devices, the coolant flow streaming through the breeder mantle is increased in length and the flow resistance is thereby increased so that for considerably reduced flow quantities, in this section the same outlet temperatures as in the fuel region are attained. The solution for this problem is achieved thus with a forced transverse flow in the breeder regions. An apparently even simpler solution, namely the introduction of a partition between the core zone and the breeder mantle must be replaced about every three years due to the radiation load and the reduction in the mechanical properties associated therewith, a fact which ought to lead to no inconsiderable difficulties with the large diameter. Another apparently simple solution would be the increasing of the flow resistance within the breeder mantle due to reduction of the spacings between the individual fuel rods. This is not technically feasible because the spacings must become small, so that for the slow flow rates, depositions would not be avoidable and would clog the element. Other features which are considered as characteristic for the invention are set forth in the appended claims. Although the invention is illustrated and described herein as embodied in fast breeder reactor, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
051014220	description	DESCRIPTION OF PREFERRED EMBODIMENT FIG. 1 illustrates in diagrammatic form a glass capillary 10 which tapers from a large end 12 to a relatively small end 14 and which has an interior bore 16 defined by the inner surface 18 of the capillary wall. The bore 16 also tapers from the large end 12 inwardly to the small end 14. The capillary may be formed into its tapered shape by conventional drawing processes, wherein a glass tube is heated and tension is applied to its opposite ends to cause the tube to stretch and draw out. As the tube is drawn, its diameter decreases substantially uniformly, producing a thin-walled capillary having a very small aperture at its smallest end. The tube may be of a fused silica; however, a higher density glass, such as lead glass, is preferred since it has better X-ray reflecting properties. Various manufacturing procedures may be used to produce the capillary, but such techniques are well known, and do not constitute a part of this invention. It has been found that a tapered, thin-walled capillary can be used to concentrate X-rays entering into the large end of the capillary if they are directed in such a way that they strike the inner surface 18 of the capillary at or below some angle less than the critical glancing angle. X-rays which enter the capillary and strike surface 18 at angles greater than the critical glancing angle will be absorbed by the wall of the capillary and will not pass through its length, while those which strike the wall surface at or below this angle will be reflected from that surface in the manner generally indicated by the dotted line 20 in FIG. 1 and will pass through the capillary, so that the capillary serves as a waveguide for these X-rays. As the reflected X-rays move from the larger end 12 toward the smaller end 14 of the capillary, they are in the form of a beam which is concentrated into a progressively smaller diameter aperture without any significant losses, so that the intensity of the beam continuously increases along the length of the capillary and the X-rays are, in effect, focused at a spot at or immediately adjacent the end 14 of the capillary. This spot is equal in diameter to the inner diameter of the end 14. Thus, the capillary reduces the diameter of the beam while increasing its intensity to provide concentrated X-ray energy at the end of the capillary. There are numerous applications for this technique of concentrating X-rays, including any use which requires high X-ray intensities at small spots. From an X-ray optical viewpoint, there is no preferred range of capillary wall thickness; this dimension is a function of the manufacturing technique used to make the capillary. It is the inner diameter of the capillary that is important. In tests of the present invention, the capillaries used had wall thicknesses of about 40 microns. As illustrated in FIG. 2, the capillary 10 preferably is coated by a plastic material 22 such as an epoxy acrylate. The acrylate layer may be applied to the outer surface of the capillary 10 after it has been drawn to the desired taper and diameter to protect the thin glass wall of the capillary and to give it strength and flexibility. The plastic coating is a thin, uniform layer which may be applied in a conventional manner. For example, after the capillary fiber has been heated and drawn to its tapered profile, it is air cooled to 50.degree. C. and passed through a cup of uncured liquid epoxy acrylate. The coated fiber is then sent through a high intensity cylindrical source of ultraviolet light that cures the acrylate coating. The coating thickness can vary from a 50 micron wall thickness at the large end of the fiber to a 225 micron wall thickness at the small end. In accordance with the present invention, both ends of the capillary are supported in the manner illustrated in FIG. 2 for the large end 12, it being understood that a similar mounting structure is used for the small end 14, as shown diagrammatically in FIG. 3. The support structure for the capillary includes, in the illustrated embodiment, an annular vertical mounting block 30 which incorporates an aperture 32 through which the end portion of the capillary extends. The aperture 32 is filled with an adhesive bonding material 34 which may be an epoxy material, and which is packed around the capillary in an uncured state. The epoxy is then cured to form an adhesive bond with the wall of the aperture 32 and with the exterior wall surface of the capillary. When cured, the bonding material 34 has sufficient strength to secure the capillary in the mounting block when tension in the axial direction is applied to it, as will be described. It has been found that if the plastic coating 22 extends completely through the aperture 32 so that the epoxy 34 contacts only the outer surface of the plastic coating 22, insufficient strength is provided to hold the capillary in tension, for when the epoxy is connected to the coating 22, the coating tends to break loose from the surface of the glass when the capillary is subjected to tension. This allows the capillary to slide longitudinally with respect to the coating and thus with respect to the mounting block, thereby releasing the tension. The angle of taper of the capillary is exaggerated in FIG. 2 for purposes of illustration, but in actual tests, wherein the degree of taper was much less than the illustrated taper, the slippage between the plastic coating 22 and the glass capillary 10 allowed the capillary to slide out of the mounting block when the blocks were moved apart to apply tension to the capillary. The epoxy did not break free from the coating, but the coating did not did not stay attached to the glass. A solution to the foregoing problem is the construction illustrated in FIG. 2, which involves stripping the plastic coating 22 away from at least a part of the end portion of the glass tube so that the coating terminates at an end 36 approximately midway through the aperture so that the bonding material 34 contacts the outer surface of the glass. The epoxy 34 bonds to the glass in the region 38 with sufficient strength to hold the capillary in the mounting block when axial tension is applied to the capillary. An additional advantage of the construction illustrated in FIG. 2 is the fact that the plastic coating 22 extends at least partially into the aperture 32 where it is in contact with, and is gripped by the bonding material 34 in the end region generally indicated at 40. This arrangement provides a cushioning effect at the point 42 where the capillary enters the bonding material 34, the plastic coating material thereby serving as a strain relief for the glass wall of the capillary to prevent breakage of the glass from the shear force applied to the capillary at point 42 by its weight. It was found that if the plastic coating 22 is stripped away from the capillary throughout the axial length of the aperture 32, so that the epoxy 34 contacts only the glass surface, a shear force is generated at the edge 42 of the epoxy which results in easy breakage of the capillary. The mounting block 30 illustrated in FIG. 2 and a matching mounting block 30' (FIG. 3) at the opposite end of the capillary are used to secure the tapered glass capillary 10 and to apply axial tension to it so that it is linear to within a a few arcseconds resolution to enable X-rays to propagate down the bore 16 of the capillary without being absorbed by the capillary wall. In order to apply the required tension, the mounting blocks 30 and 30' are mounted for longitudinal motion in the direction of the longitudinal axis 44 of the capillary on an optical rail 46 (see FIG. 3) with the capillary 10 stretched between the two mounting blocks. The mounting blocks may be located in housings 48 and 48', as by means of a suitable gimbal mount diagrammatically illustrated in FIG. 2 by inner gimbal ring 50 in which the mounting block 30 is secured, as by a mounting ring 52. The inner ring 50 is pivotally mounted by pins 54 and 56 to a gimbal outer support 58 for motion about a horizontal axis. The gimbal ring 58 may, in turn, be mounted on a rotatable base 60 for pivotal motion about a vertical axis, as illustrated in FIG. 3 in housing 48, which is broken away to better illsutrate the gimbal mounting. The gimbal mounting preferably is a motor-driven, adjustable precision mounting which permits precise alignment of the mounting block with the longitudinal axis of the capillary. A suitable gimbal mounting is the Oriel Motorized Mirror Mount, equipped with a "Motor Mike" precision drive, manufactured by Oriel Corporation, Stratford, Conn. This mounting permits alignment of the end portions 12 and 14 of the capillary with the main body portion thereof between the mounting blocks, so that the capillary remains essentially straight along its entire axial length. The housings 48 and 48' are mounted on the optical rail for relative motion parallel to the longitudinal axis 44 of the capillary which is stretched between them. Thus, for example, the housing 48 may be secured to a mounting platform 62 carried by a support base 64 fixed to the optical rail. The corresponding housing 48' is secured to a corresponding platform 62' which is also carried by a support base 64', which in this case preferably is a traveler movably mounted on the optical rail 46. The traveler is positionable by means, for example, of a threaded drive rod 68 which may be motor driven or manually operated by means of a hand wheel 70. The housing 48' is movable longitudinally along the drive rod 68 in the directions indicated by the arrow 72 so as to apply a selected amount of tension to the capillary 10. By rotation of the drive rod 68, the traveler 64' is moved longitudinally with respect to the fixed base 64 so that the capillary 10 can be pulled taut to effectively eliminate sag in the capillary and to insure that its longitudinal axis 44 is linear. The gimbal mounting for the mounting blocks 30 (and 30' for housing 48'), which permits the ends of the capillary to be aligned with the longitudinal axis between the two mounting blocks, insures a straight path completely through the capillary bore 16 for the propagation of X-rays. X-rays from a suitable X-ray source, diagrammatically illustrated at 80 in FIG. 2, are directed into the large end 12 of the capillary after it has been fastened to the mounting blocks 30 and 30', the blocks have been secured in the housings 48 and 48', and tension has been applied to the capillary by adjustment of the traveler 64'. The application of sufficient tension, together with precise adjustment of the gimbal mounting allows the axis of the capillary to be aligned within a few arcseconds precision, and through the adjustment of the gimbals and the tension of the capillary, X-ray flux through the capillary is maximized. Since, for the propagation of X-rays, the critical angles for total reflection are on the order of milliradians, and since the cladding material 22 and the glass wall of the capillary 10 absorb X-rays rather than propagating them, the requirements for maintaining a straight axial line through the capillary are very high, and are much greater, for example, than would be the requirements for propagating light through an optical fiber. In order to further maximize the propagation of X-rays through the capillary, the large end 12 of the capillary is enclosed by a gas-tight enclosure 82 including side walls 84, which may be metal, for example, and an end wall 86 formed of X-ray transparent material such as Kapton tape. Helium gas is supplied from a source 88 by way of an inlet 90 to the interior 92 of the enclosure 82 under slight pressure so that the helium flows through inlet end 12 into the interior bore 16 of the capillary. The helium flows through the capillary and exits from the aperture at the small end 14, thereby filling the capillary and displacing the air. A small flow of helium into the large opening 12 of the capillary translates into a larger flow rate exiting from the small opening 14, with the flow exerting sufficient force to clear air out of the capillary. Since helium is transparent to X-rays, a significant increase in the flux density of X-rays at the output end 14 is attained. For example, with X-rays having an energy level of 8 keV an air-filled capillary 1.6 meters long has its flux density reduced by a factor of 5 due to the absorption of X-rays in air. At lower X-ray energies, this loss is even greater. However, substituting helium for air increases the 8 keV X-ray flux by 5 times. It is noted that the helium exiting the small end of the capillary may be recaptured, if desired, but can be allowed to dissipate since the flow rate is very low. In a test of the present invention, a capillary 1.6 meters long and having a diameter of 470 micrometers at its large end 12 and 110 micrometers at its small end 14 was mounted in the manner described above. The capillary was gripped at its two ends by means of mounting blocks such as those illustrated at 30 and 30' and was pulled straight by applying longitudinal tension to the capillary. The tensile strength of the glass was sufficient to substantially eliminate sag in the capillary, and the adhesive bonding in the manner illustrated prevented shear forces from breaking the glass at its securing points. The metal/glass bond did not separate, and the metal/acrylate bond served as a strain relief. The use of a gimbal mounting at the ends of the fiber permitted precise alignment of the capillary axis, and the use of helium within the capillary bore further maximized the density of the X-rays at the small-end opening of the capillary, thereby effectively focusing the X-rays to a high intensity spot having a diameter of 110 micrometers. The provision of a plastic coating on the X-ray capillary provides another unexpected advantage. It has been found that such a coating provides a degree of flexibility to the thin glass capillary, enabling the capillary to be curved into an arc of a relatively large radius; for example, several meters, without breaking. It has been found that such a smoothly curved, large-radius arc will still propagate X-rays, although there is some absorption, and such a curvature allows an X-ray beam to be redirected. This is important, because present X-ray technology can steer a beam only over a limited angular range of about 0.3 degrees. Thus, for example, a synchrotron source generally directs its output X-rays horizontally, and present day X-ray optics do not permit such beams to be significantly redirected. However, with a carefully supported large-radius curved capillary, the output X-rays from a synchrotron could be directed vertically or in any direction in the horizontal plane. Although the present invention has been described in terms of a preferred embodiment thereof, it will be understood that variations and modifications may be made without departing from the true spirit and scope thereof. Thus, for example, variations in the mounting mechanism on the optical rail may be utilized, and the gimbal mounts diagrammatically illustrated in the drawings preferably will be precision mounts which may be adjusted for accurate alignment. Accordingly, the true spirit and scope of the invention is limited only by the following claims.
	description	This application is a continuation of U.S. application Ser. No. 13/261,901, filed Feb. 25, 2015, which is a national stage entry of PCT Application No. PCT/US2012/065071, filed Nov. 14, 2012, which claims the benefit of U.S. Provisional Application No. 61/559,721, filed Nov. 15, 2011, and U.S. Provisional Application No. 61/559,154, filed Nov. 14, 2011, the disclosures of all of which are fully incorporated herein by reference. The embodiments described herein relate generally to magnetic plasma confinement systems and, more particularly, to systems and methods that facilitate forming and maintaining Field Reversed Configurations with superior stability as well as particle, energy and flux confinement. The Field Reversed Configuration (FRC) belongs to the class of magnetic plasma confinement topologies known as compact toroids (CT). It exhibits predominantly poloidal magnetic fields and possesses zero or small self-generated toroidal fields (see M. Tuszewski, Nucl. Fusion 28, 2033 (1988)). The attractions of such a configuration are its simple geometry for ease of construction and maintenance, a natural unrestricted divertor for facilitating energy extraction and ash removal, and very high β (β is the ratio of the average plasma pressure to the average magnetic field pressure inside the FRC), i.e., high power density. The high β nature is advantageous for economic operation and for the use of advanced, aneutronic fuels such as D-He3 and p-B11. The traditional method of forming an FRC uses the field-reversed θ-pinch technology, producing hot, high-density plasmas (see A. L. Hoffman and J. T. Slough, Nucl. Fusion 33, 27 (1993)). A variation on this is the translation-trapping method in which the plasma created in a theta-pinch “source” is more-or-less immediately ejected out one end into a confinement chamber. The translating plasmoid is then trapped between two strong mirrors at the ends of the chamber (see, for instance, H. Himura, S. Okada, S. Sugimoto, and S. Goto, Phys. Plasmas 2, 191 (1995)). Once in the confinement chamber, various heating and current drive methods may be applied such as beam injection (neutral or neutralized), rotating magnetic fields, RF or ohmic heating, etc. This separation of source and confinement functions offers key engineering advantages for potential future fusion reactors. FRCs have proved to be extremely robust, resilient to dynamic formation, translation, and violent capture events. Moreover, they show a tendency to assume a preferred plasma state (see e.g. H. Y. Guo, A. L. Hoffman, K. E. Miller, and L. C. Steinhauer, Phys. Rev. Lett. 92, 245001 (2004)). Significant progress has been made in the last decade developing other FRC formation methods: merging spheromaks with oppositely-directed helicities (see e.g. Y. Ono, M. Inomoto, Y. Ueda, T. Matsuyama, and T. Okazaki, Nucl. Fusion 39, 2001 (1999)) and by driving current with rotating magnetic fields (RMF) (see e.g. I. R. Jones, Phys. Plasmas 6, 1950 (1999)) which also provides additional stability. Recently, the collision-merging technique, proposed long ago (see e.g. D. R. Wells, Phys. Fluids 9, 1010 (1966)) has been significantly developed further: two separate theta-pinches at opposite ends of a confinement chamber simultaneously generate two plasmoids and accelerate the plasmoids toward each other at high speed; they then collide at the center of the confinement chamber and merge to form a compound FRC. In the construction and successful operation of one of the largest FRC experiments to date, the conventional collision-merging method was shown to produce stable, long-lived, high-flux, high temperature FRCs (see e.g. M. Binderbauer, H. Y. Guo, M. Tuszewski et al., Phys. Rev. Lett. 105, 045003 (2010)). FRCs consist of a torus of closed field lines inside a separatrix, and of an annular edge layer on the open field lines just outside the separatrix. The edge layer coalesces into jets beyond the FRC length, providing a natural divertor. The FRC topology coincides with that of a Field-Reversed-Mirror plasma. However, a significant difference is that the FRC plasma has a β of about 10. The inherent low internal magnetic field provides for a certain indigenous kinetic particle population, i.e. particles with large larmor radii, comparable to the FRC minor radius. It is these strong kinetic effects that appear to at least partially contribute to the gross stability of past and present FRCs, such as those produced in the collision-merging experiment. Typical past FRC experiments have been dominated by convective losses with energy confinement largely determined by particle transport. Particles diffuse primarily radially out of the separatrix volume, and are then lost axially in the edge layer. Accordingly, FRC confinement depends on the properties of both closed and open field line regions. The particle diffusion time out of the separatrix scales as τ⊥˜a2/D⊥ (a·rs/4, where rs is the central separatrix radius), and D⊥ is a characteristic FRC diffusivity, such as D⊥˜12.5 ρie, with ρie representing the ion gyroradius, evaluated at an externally applied magnetic field. The edge layer particle confinement time τ∥ is essentially an axial transit time in past FRC experiments. In steady-state, the balance between radial and axial particle losses yields a separatrix density gradient lengths δ˜(D⊥τ∥)1/2. The FRC particle confinement time scales as (τ⊥τ∥)1/2 for past FRCs that have substantial density at the separatrix (see e.g. M. Tuszewski, “Field Reversed Configurations,” Nucl. Fusion 28, 2033 (1988)). Another drawback of prior FRC system designs was the need to use external multipoles to control rotational instabilities such as the fast growing n=2 interchange instabilities. In this way the typical externally applied quadrupole fields provided the required magnetic restoring pressure to dampen the growth of these unstable modes. While this technique is adequate for stability control of the thermal bulk plasma, it poses a severe problem for more kinetic FRCs or advanced hybrid FRCs, where a highly kinetic large orbit particle population is combined with the usual thermal plasma. In these systems, the distortions of the axisymmetric magnetic field due to such multipole fields leads to dramatic fast particle losses via collisionless stochastic diffusion, a consequence of the loss of conservation of canonical angular momentum. A novel solution to provide stability control without enhancing diffusion of any particles is, thus, important to take advantage of the higher performance potential of these never-before explored advanced FRC concepts. In light of the foregoing, it is, therefore, desirable to improve the confinement and stability of FRCs in order to use steady state FRCs as a pathway to a whole variety of applications from compact neutron sources (for medical isotope production and nuclear waste remediation), to mass separation and enrichment systems, and to a reactor core for fusion of light nuclei for the future generation of energy. The present embodiments provided herein are directed to systems and methods that facilitate the formation and maintenance of new High Performance Field Reversed Configurations (FRCs). In accordance with this new High Performance FRC paradigm, the present system combines a host of novel ideas and means to dramatically improve FRC confinement of particles, energy and flux as well as provide stability control without negative side-effects. An FRC system provided herein includes a central confinement vessel surrounded by two diametrically opposed reversed-field-theta-pinch formation sections and, beyond the formation sections, two divertor chambers to control neutral density and impurity contamination. A magnetic system includes a series of quasi-dc coils that are situated at axial positions along the components of the FRC system, quasi-dc mirror coils between either end of the confinement chamber and the adjacent formation sections, and mirror plugs comprising compact quasi-dc mirror coils between each of the formation sections and divertors that produce additional guide fields to focus the magnetic flux surfaces towards the divertor. The formation sections include modular pulsed power formation systems that enable FRCs to be formed in-situ and then accelerated and injected (=static formation) or formed and accelerated simultaneously (=dynamic formation). The FRC system includes neutral atom beam injectors and a pellet injector. Gettering systems are also included as well as axial plasma guns. Biasing electrodes are also provided for electrical biasing of open flux surfaces. The systems, methods, features and advantages of the invention will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional methods, features and advantages be included within this description, be within the scope of the invention, and be protected by the accompanying claims. It is also intended that the invention is not limited to require the details of the example embodiments. It should be noted that the figures are not necessarily drawn to scale and that elements of similar structures or functions are generally represented by like reference numerals for illustrative purposes throughout the figures. It also should be noted that the figures are only intended to facilitate the description of the various embodiments described herein. The figures do not necessarily describe every aspect of the teachings disclosed herein and do not limit the scope of the claims. The present embodiments provided herein are directed to systems and methods that facilitate forming and maintaining High Performance Field Reversed Configurations (FRCs) with superior stability as well as superior particle, energy and flux confinement over conventional FRCs. Various ancillary systems and operating modes have been explored to assess whether there is a superior confinement regime in FRCs. These efforts have led to breakthrough discoveries and the development of a High Performance FRC paradigm described herein. In accordance with this new paradigm, the present systems and methods combine a host of novel ideas and means to dramatically improve FRC confinement as illustrated in FIG. 1 as well as provide stability control without negative side-effects. As discussed in greater detail below, FIG. 1 depicts particle confinement in an FRC system 10 described below (see FIGS. 2 and 3), operating in accordance a High Performance FRC regime (HPF) for forming and maintaining an FRC versus operating in accordance with a conventional regime CR for forming and maintaining an FRC, and versus particle confinement in accordance with conventional regimes for forming and maintaining an FRC used in other experiments. The present disclosure will outline and detail the innovative individual components of the FRC system 10 and methods as well as their collective effects. Description of the FRC System Vacuum System FIGS. 2 and 3 depict a schematic of the present FRC system 10. The FRC system 10 includes a central confinement vessel 100 surrounded by two diametrically opposed reversed-field-theta-pinch formation sections 200 and, beyond the formation sections 200, two divertor chambers 300 to control neutral density and impurity contamination. The present FRC system 10 was built to accommodate ultrahigh vacuum and operates at typical base pressures of 10-8 torr. Such vacuum pressures require the use of double-pumped mating flanges between mating components, metal O-rings, high purity interior walls, as well as careful initial surface conditioning of all parts prior to assembly, such as physical and chemical cleaning followed by 24 hour 250° C. vacuum baking and Hydrogen glow discharge cleaning. The reversed-field-theta-pinch formation sections 200 are standard field-reversed-theta-pinches (FRTPs), albeit with an advanced pulsed power formation system discussed in detail below (see FIGS. 4 through 6). Each formation section 200 is made of standard opaque industrial grade quartz tubes that feature a 2 millimeter inner lining of ultrapure quartz. The confinement chamber 100 is made of stainless steel to allow a multitude of radial and tangential ports; it also serves as a flux conserver on the timescale of the experiments described below and limits fast magnetic transients. Vacuums are created and maintained within the FRC system 10 with a set of dry scroll roughing pumps, turbo molecular pumps and cryo pumps. Magnetic System The magnetic system 400 is illustrated in FIGS. 2 and 3. FIG. 2, amongst other features, illustrates an FRC magnetic flux and density contours (as functions of the radial and axial coordinates) pertaining to an FRC 450 producible by the FRC system 10. These contours were obtained by a 2-D resistive Hall-MHD numerical simulation using code developed to simulate systems and methods corresponding to the FRC system 10, and agree well with measured experimental data. As seen in FIG. 2, the FRC 450 consists of a torus of closed field lines at the interior 453 of the FRC 450 inside a separatrix 451, and of an annular edge layer 456 on the open field lines 452 just outside the separatrix 451. The edge layer 456 coalesces into jets 454 beyond the FRC length, providing a natural divertor. The main magnetic system 410 includes a series of quasi-dc coils 412, 414, and 416 that are situated at particular axial positions along the components, i.e., along the confinement chamber 100, the formation sections 200 and the divertors 300, of the FRC system 10. The quasi-dc coils 412, 414 and 416 are fed by quasi-dc switching power supplies and produce basic magnetic bias fields of about 0.1 T in the confinement chamber 100, the formation sections 200 and the divertors 300. In addition to the quasi-dc coils 412, 414 and 416, the main magnetic system 410 includes quasi-dc mirror coils 420 (fed by switching supplies) between either end of the confinement chamber 100 and the adjacent formation sections 200. The quasi-dc mirror coils 420 provide magnetic mirror ratios of up to 5 and can be independently energized for equilibrium shaping control. In addition, mirror plugs 440, are positioned between each of the formation sections 200 and divertors 300. The mirror plugs 440 comprise compact quasi-dc mirror coils 430 and mirror plug coils 444. The quasi-dc mirror coils 430 include three coils 432, 434 and 436 (fed by switching supplies) that produce additional guide fields to focus the magnetic flux surfaces 455 towards the small diameter passage 442 passing through the mirror plug coils 444. The mirror plug coils 444, which wrap around the small diameter passage 442 and are fed by LC pulsed power circuitry, produce strong magnetic mirror fields of up to 4 T. The purpose of this entire coil arrangement is to tightly bundle and guide the magnetic flux surfaces 455 and end-streaming plasma jets 454 into the remote chambers 310 of the divertors 300. Finally, a set of saddle-coil “antennas” 460 (see FIG. 15) are located outside the confinement chamber 100, two on each side of the mid-plane, and are fed by dc power supplies. The saddle-coil antennas 460 can be configured to provide a quasi-static magnetic dipole or quadrupole field of about 0.01 T for controlling rotational instabilities and/or electron current control. The saddle-coil antennas 460 can flexibly provide magnetic fields that are either symmetric or antisymmetric about the machine's midplane, depending on the direction of the applied currents. Pulsed Power Formation Systems The pulsed power formation systems 210 operate on a modified theta-pinch principle. There are two systems that each power one of the formation sections 200. FIGS. 4 through 6 illustrate the main building blocks and arrangement of the formation systems 210. The formation system 210 is composed of a modular pulsed power arrangement that consists of individual units (=skids) 220 that each energize a sub-set of coils 232 of a strap assembly 230 (=straps) that wrap around the formation quartz tubes 240. Each skid 220 is composed of capacitors 221, inductors 223, fast high current switches 225 and associated trigger 222 and dump circuitry 224. In total, each formation system 210 stores between 350-400 kJ of capacitive energy, which provides up to 35 GW of power to form and accelerate the FRCs. Coordinated operation of these components is achieved via a state-of-the-art trigger and control system 222 and 224 that allows synchronized timing between the formation systems 210 on each formation section 200 and minimizes switching jitter to tens of nanoseconds. The advantage of this modular design is its flexible operation: FRCs can be formed in-situ and then accelerated and injected (=static formation) or formed and accelerated at the same time (=dynamic formation). Neutral Beam Injectors Neutral atom beams are deployed on the FRC system 10 to provide heating and current drive as well as to develop fast particle pressure. As shown in FIGS. 3 and 8, the individual beam lines comprising neutral atom beam injector systems 610 and 640 are located around the central confinement chamber 100 and inject fast particles tangentially to the FRC plasma (and perpendicular to the axis of the confinement chamber 100) with an impact parameter such that the target trapping zone lies well within the separatrix 451 (see FIG. 2). Each injector system 610 and 640 is capable of projecting up to 1 MW of neutral beam power into the FRC plasma with particle energies between 20 and 40 keV. The systems 610 and 640 are based on positive ion multi-aperture extraction sources and utilize geometric focusing, inertial cooling of the ion extraction grids and differential pumping. Apart from using different plasma sources, the systems 610 and 640 are primarily differentiated by their physical design to meet their respective mounting locations, yielding side and top injection capabilities. Typical components of these neutral beam injectors are specifically illustrated in FIG. 7 for the side injector systems 610. As shown in FIG. 7, each individual neutral beam system 610 includes an RF plasma source 612 at an input end (this is substituted with an arc source in systems 640) with a magnetic screen 614 covering the end. An ion optical source and acceleration grids 616 is coupled to the plasma source 612 and a gate valve 620 is positioned between the ion optical source and acceleration grids 616 and a neutralizer 622. A deflection magnet 624 and an ion dump 628 are located between the neutralizer 622 and an aiming device 630 at the exit end. A cooling system comprises two cryo-refrigerators 634, two cryopanels 636 and a LN2 shroud 638. This flexible design allows for operation over a broad range of FRC parameters. Pellet Injector To provide a means to inject new particles and better control FRC particle inventory, a 12-barrel pellet injector 700 (see e.g. I. Vinyar et al., “Pellet Injectors Developed at PELIN for JET, TAE, and HL-2A,” Proceedings of the 26th Fusion Science and Technology Symposium, 09/27 to 10/01 (2010)) is utilized on FRC system 10. FIG. 3 illustrates the layout of the pellet injector 700 on the FRC system 10. The cylindrical pellets (D˜1 mm, L˜1-2 mm) are injected into the FRC with a velocity in the range of 150-250 km/s. Each individual pellet contains about 5×1019 hydrogen atoms, which is comparable to the FRC particle inventory. Gettering Systems It is well known that neutral halo gas is a serious problem in all confinement systems. The charge exchange and recycling (release of cold impurity material from the wall) processes can have a devastating effect on energy and particle confinement. In addition, any significant density of neutral gas at or near the edge will lead to prompt losses of or at least severely curtail the lifetime of injected large orbit (high energy) particles (large orbit refers to particles having orbits on the scale of the FRC topology or at least orbit radii much larger than the characteristic magnetic field gradient length scale)—a fact that is detrimental to all energetic plasma applications, including fusion via auxiliary beam heating. Surface conditioning is a means by which the detrimental effects of neutral gas and impurities can be controlled or reduced in a confinement system. To this end the FRC system 10 provided herein employs Titanium and Lithium deposition systems 810 and 820 that coat the plasma facing surfaces of the confinement chamber (or vessel) 100 and diverters 300 with films (tens of micrometers thick) of Ti and/or Li. The coatings are achieved via vapor deposition techniques. Solid Li and/or Ti are evaporated and/or sublimated and sprayed onto nearby surfaces to form the coatings. The sources are atomic ovens with guide nozzles (in case of Li) 822 or heated spheres of solid with guide shrouding (in case of Ti) 812. Li evaporator systems typically operate in a continuous mode while Ti sublimators are mostly operated intermittently in between plasma operation. Operating temperatures of these systems are above 600° C. to obtain fast deposition rates. To achieve good wall coverage, multiple strategically located evaporator/sublimator systems are necessary. FIG. 9 details a preferred arrangement of the gettering deposition systems 810 and 820 in the FRC system 10. The coatings act as gettering surfaces and effectively pump atomic and molecular hydrogenic species (H and D). The coatings also reduce other typical impurities such as Carbon and Oxygen to insignificant levels. Mirror Plugs As stated above, the FRC system 10 employs sets of mirror coils 420, 430, and 444 as shown in FIGS. 2 and 3. A first set of mirror coils 420 is located at the two axial ends of the confinement chamber 100 and is independently energized from the confinement coils 412, 414 and 416 of the main magnetic system 410. The first set of mirror coils 420 primarily helps to steer and axially contain the FRC 450 during merging and provides equilibrium shaping control during sustainment. The first mirror coil set 420 produces nominally higher magnetic fields (around 0.4 to 0.5 T) than the central confinement field produced by the central confinement coils 412. The second set of mirror coils 430, which includes three compact quasi-dc mirror coils 432, 434 and 436, is located between the formation sections 200 and the divertors 300 and are driven by a common switching power supply. The mirror coils 432, 434 and 436, together with the more compact pulsed mirror plug coils 444 (fed by a capacitive power supply) and the physical constriction 442 form the mirror plugs 440 that provide a narrow low gas conductance path with very high magnetic fields (between 2 to 4 T with risetimes of about 10 to 20 ms). The most compact pulsed mirror coils 444 are of compact radial dimensions, bore of 20 cm and similar length, compared to the meter-plus-scale bore and pancake design of the confinement coils 412, 414 and 416. The purpose of the mirror plugs 440 is multifold: (1) The coils 432, 434, 436 and 444 tightly bundle and guide the magnetic flux surfaces 452 and end-streaming plasma jets 454 into the remote divertor chambers 300. This assures that the exhaust particles reach the divertors 300 appropriately and that there are continuous flux surfaces 455 that trace from the open field line 452 region of the central FRC 450 all the way to the divertors 300. (2) The physical constrictions 442 in the FRC system 10, through which that the coils 432, 434, 436 and 444 enable passage of the magnetic flux surfaces 452 and plasma jets 454, provide an impediment to neutral gas flow from the plasma guns 350 that sit in the divertors 300. In the same vein, the constrictions 442 prevent back-streaming of gas from the formation sections 200 to the divertors 300 thereby reducing the number of neutral particles that has to be introduced into the entire FRC system 10 when commencing the start up of an FRC. (3) The strong axial mirrors produced by the coils 432, 434, 436 and 444 reduce axial particle losses and thereby reduce the parallel particle diffusivity on open field lines. Axial Plasma Guns Plasma streams from guns 350 mounted in the divertor chambers 310 of the divertors 300 are intended to improve stability and neutral beam performance. The guns 350 are mounted on axis inside the chamber 310 of the divertors 300 as illustrated in FIGS. 3 and 10 and produce plasma flowing along the open flux lines 452 in the divertor 300 and towards the center of the confinement chamber 100. The guns 350 operate at a high density gas discharge in a washer-stack channel and are designed to generate several kiloamperes of fully ionized plasma for 5 to 10 ms. The guns 350 include a pulsed magnetic coil that matches the output plasma stream with the desired size of the plasma in the confinement chamber 100. The technical parameters of the guns 350 are characterized by a channel having a 5 to 13 cm outer diameter and up to about 10 cm inner diameter and provide a discharge current of 10-15 kA at 400-600 V with a gun-internal magnetic field of between 0.5 to 2.3 T. The gun plasma streams can penetrate the magnetic fields of the mirror plugs 440 and flow into the formation section 200 and confinement chamber 100. The efficiency of plasma transfer through the mirror plug 440 increases with decreasing distance between the gun 350 and the plug 440 and by making the plug 440 wider and shorter. Under reasonable conditions, the guns 350 can each deliver approximately 1022 protons/s through the 2 to 4 T mirror plugs 440 with high ion and electron temperatures of about 150 to 300 eV and about 40 to 50 eV, respectively. The guns 350 provide significant refueling of the FRC edge layer 456, and an improved overall FRC particle confinement. To further increase the plasma density, a gas box could be utilized to puff additional gas into the plasma stream from the guns 350. This technique allows a several-fold increase in the injected plasma density. In the FRC system 10, a gas box installed on the divertor 300 side of the mirror plugs 440 improves the refueling of the FRC edge layer 456, formation of the FRC 450, and plasma line-tying. Given all the adjustment parameters discussed above and also taking into account that operation with just one or both guns is possible, it is readily apparent that a wide spectrum of operating modes is accessible. Biasing Electrodes Electrical biasing of open flux surfaces can provide radial potentials that give rise to azimuthal E×B motion that provides a control mechanism, analogous to turning a knob, to control rotation of the open field line plasma as well as the actual FRC core 450 via velocity shear. To accomplish this control, the FRC system 10 employs various electrodes strategically placed in various parts of the machine. FIG. 3 depicts biasing electrodes positioned at preferred locations within the FRC system 10. In principle, there are 4 classes of electrodes: (1) point electrodes 905 in the confinement chamber 100 that make contact with particular open field lines 452 in the edge of the FRC 450 to provide local charging, (2) annular electrodes 900 between the confinement chamber 100 and the formation sections 200 to charge far-edge flux layers 456 in an azimuthally symmetric fashion, (3) stacks of concentric electrodes 910 in the divertors 300 to charge multiple concentric flux layers 455 (whereby the selection of layers is controllable by adjusting coils 416 to adjust the divertor magnetic field so as to terminate the desired flux layers 456 on the appropriate electrodes 910), and finally (4) the anodes 920 (see FIG. 10) of the plasma guns 350 themselves (which intercept inner open flux surfaces 455 near the separatrix of the FRC 450). FIGS. 10 and 11 show some typical designs for some of these. In all cases these electrodes are driven by pulsed or dc power sources at voltages up to about 800 V. Depending on electrode size and what flux surfaces are intersected, currents can be drawn in the kilo-ampere range. Un-Sustained Operation of FRC System—Conventional Regime The standard plasma formation on the FRC system 10 follows the well-developed reversed-field-theta-pinch technique. A typical process for starting up an FRC commences by driving the quasi-dc coils 412, 414, 416, 420, 432, 434 and 436 to steady state operation. The RFTP pulsed power circuits of the pulsed power formation systems 210 then drive the pulsed fast reversed magnet field coils 232 to create a temporary reversed bias of about −0.05 T in the formation sections 200. At this point a predetermined amount of neutral gas at 9-20 psi is injected into the two formation volumes defined by the quartz-tube chambers 240 of the (north and south) formation sections 200 via a set of azimuthally-oriented puff-vales at flanges located on the outer ends of the formation sections 200. Next a small RF (˜hundreds of kilo-hertz) field is generated from a set of antennas on the surface of the quartz tubes 240 to create pre-pre-ionization in the form of local seed ionization regions within the neutral gas columns. This is followed by applying a theta-ringing modulation on the current driving the pulsed fast reversed magnet field coils 232, which leads to more global pre-ionization of the gas columns. Finally, the main pulsed power banks of the pulsed power formation systems 210 are fired to drive pulsed fast reversed magnet field coils 232 to create a forward-biased field of up to 0.4 T. This step can be time-sequenced such that the forward-biased field is generated uniformly throughout the length of the formation tubes 240 (static formation) or such that a consecutive peristaltic field modulation is achieved along the axis of the formation tubes 240 (dynamic formation). In this entire formation process, the actual field reversal in the plasma occurs rapidly, within about 5 μs. The multi-gigawatt pulsed power delivered to the forming plasma readily produces hot FRCs which are then ejected from the formation sections 200 via application of either a time-sequenced modulation of the forward magnetic field (magnetic peristalsis) or temporarily increased currents in the last coils of coil sets 232 near the axial outer ends of the formation tubes 210 (forming an axial magnetic field gradient that points axially towards the confinement chamber 100). The two (north and south) formation FRCs so formed and accelerated then expand into the larger diameter confinement chamber 100, where the quasi-dc coils 412 produce a forward-biased field to control radial expansion and provide the equilibrium external magnetic flux. Once the north and south formation FRCs arrive near the midplane of the confinement chamber 100, the FRCs collide. During the collision the axial kinetic energies of the north and south formation FRCs are largely thermalized as the FRCs merge ultimately into a single FRC 450. A large set of plasma diagnostics are available in the confinement chamber 100 to study the equilibria of the FRC 450. Typical operating conditions in the FRC system 10 produce compound FRCs with separatrix radii of about 0.4 m and about 3 m axial extend. Further characteristics are external magnetic fields of about 0.1 T, plasma densities around 5×1019 m−3 and total plasma temperature of up to 1 keV. Without any sustainment, i.e., no heating and/or current drive via neutral beam injection or other auxiliary means, the lifetime of these FRCs is limited to about 1 ms, the indigenous characteristic configuration decay time. Experimental Data of Unsustained Operation—Conventional Regime FIG. 12 shows a typical time evolution of the excluded flux radius, rΔΦ, which approximates the separatrix radius, rS, to illustrate the dynamics of the theta-pinch merging process of the FRC 450. The two (north and south) individual plasmoids are produced simultaneously and then accelerated out of the respective formation sections 200 at a supersonic speed, vZ˜250 km/s, and collide near the midplane at z=0. During the collision the plasmoids compress axially, followed by a rapid radial and axial expansion, before eventually merging to form an FRC 450. Both radial and axial dynamics of the merging FRC 450 are evidenced by detailed density profile measurements and bolometer-based tomography. Data from a representative un-sustained discharge of the FRC system 10 are shown as functions of time in FIGS. 13A, 13B, 13C, and 13D. The FRC is initiated at t=0. The excluded flux radius at the machine's axial mid-plane is shown in FIG. 13A. This data is obtained from an array of magnetic probes, located just inside the confinement chamber's stainless steel wall, that measure the axial magnetic field. The steel wall is a good flux conserver on the time scales of this discharge. Line-integrated densities are shown in FIG. 13B, from a 6-chord CO2/He—Ne interferometer located at z=0. Taking into account vertical (y) FRC displacement, as measured by bolometric tomography, Abel inversion yields the density contours of FIG. 13C. After some axial and radial sloshing during the first 0.1 ms, the FRC settles with a hollow density profile. This profile is fairly flat, with substantial density on axis, as required by typical 2-D FRC equilibria. Total plasma temperature is shown in FIG. 13D, derived from pressure balance and fully consistent with Thomson scattering and spectroscopy measurements. Analysis from the entire excluded flux array indicates that the shape of the FRC separatrix (approximated by the excluded flux axial profiles) evolves gradually from racetrack to elliptical. This evolution, shown in FIG. 14, is consistent with a gradual magnetic reconnection from two to a single FRC. Indeed, rough estimates suggest that in this particular instant about 10% of the two initial FRC magnetic fluxes reconnects during the collision. The FRC length shrinks steadily from 3 down to about 1 m during the FRC lifetime. This shrinkage, visible in FIG. 14, suggests that mostly convective energy loss dominates the FRC confinement. As the plasma pressure inside the separatrix decreases faster than the external magnetic pressure, the magnetic field line tension in the end regions compresses the FRC axially, restoring axial and radial equilibrium. For the discharge discussed in FIGS. 13A, 13B, 13C, 13D and 14, the FRC magnetic flux, particle inventory, and thermal energy (about 10 mWb, 7×1019 particles, and 7 kJ, respectively) decrease by roughly an order of magnitude in the first millisecond, when the FRC equilibrium appears to subside. Sustained Operation—HPF Regime The examples in FIGS. 12 to 14 are characteristic of decaying FRCs without any sustainment. However, several techniques are deployed on the FRC system 10 to further improve FRC confinement (inner core and edge layer) to the HPF regime and sustain the configuration. Neutral Beams First, fast (H) neutrals are injected perpendicular to BZ in beams from the eight neutral beam injectors 600. The beams of fast neutrals are injected from the moment the north and south formation FRCs merge in the confinement chamber 100 into one FRC 450. The fast ions, created primarily by charge exchange, have betatron orbits (with primary radii on the scale of the FRC topology or at least much larger than the characteristic magnetic field gradient length scale) that add to the azimuthal current of the FRC 450. After some fraction of the discharge (after 0.5 to 0.8 ms into the shot), a sufficiently large fast ion population significantly improves the inner FRC's stability and confinement properties (see e.g. M. W. Binderbauer and N. Rostoker, Plasma Phys. 56, part 3, 451 (1996)). Furthermore, from a sustainment perspective, the beams from the neutral beam injectors 600 are also the primary means to drive current and heat the FRC plasma. In the plasma regime of the FRC system 10, the fast ions slow down primarily on plasma electrons. During the early part of a discharge, typical orbit-averaged slowing-down times of fast ions are 0.3-0.5 ms, which results in significant FRC heating, primarily of electrons. The fast ions make large radial excursions outside of the separatrix because the internal FRC magnetic field is inherently low (about 0.03 T on average for a 0.1 T external axial field). The fast ions would be vulnerable to charge exchange loss, if the neutral gas density were too high outside of the separatrix. Therefore, wall gettering and other techniques (such as the plasma gun 350 and mirror plugs 440 that contribute, amongst other things, to gas control) deployed on the FRC system 10 tend to minimize edge neutrals and enable the required build-up of fast ion current. Pellet Injection When a significant fast ion population is built up within the FRC 450, with higher electron temperatures and longer FRC lifetimes, frozen H or D pellets are injected into the FRC 450 from the pellet injector 700 to sustain the FRC particle inventory of the FRC 450. The anticipated ablation timescales are sufficiently short to provide a significant FRC particle source. This rate can also be increased by enlarging the surface area of the injected piece by breaking the individual pellet into smaller fragments while in the barrels or injection tubes of the pellet injector 700 and before entering the confinement chamber 100, a step that can be achieved by increasing the friction between the pellet and the walls of the injection tube by tightening the bend radius of the last segment of the injection tube right before entry into the confinement chamber 100. By virtue of varying the firing sequence and rate of the 12 barrels (injection tubes) as well as the fragmentation, it is possible to tune the pellet injection system 700 to provide just the desired level of particle inventory sustainment. In turn, this helps maintain the internal kinetic pressure in the FRC 450 and sustained operation and lifetime of the FRC 450. Once the ablated atoms encounter significant plasma in the FRC 450, they become fully ionized. The resultant cold plasma component is then collisionally heated by the indigenous FRC plasma. The energy necessary to maintain a desired FRC temperature is ultimately supplied by the beam injectors 600. In this sense the pellet injectors 700 together with the neutral beam injectors 600 form the system that maintains a steady state and sustains the FRC 450. Saddle Coils To achieve steady state current drive and maintain the required ion current it is desirable to prevent or significantly reduce electron spin up due to the electron-ion frictional force (resulting from collisional ion electron momentum transfer). The FRC system 10 utilizes an innovative technique to provide electron breaking via an externally applied static magnetic dipole or quadrupole field. This is accomplished via the external saddle coils 460 depicted in FIG. 15. The transverse applied radial magnetic field from the saddle coils 460 induces an axial electric field in the rotating FRC plasma. The resultant axial electron current interacts with the radial magnetic field to produce an azimuthal breaking force on the electrons, Fθ=−σVeθ<\|Br\|2>. For typical conditions in the FRC system 10, the required applied magnetic dipole (or quadrupole) field inside the plasma needs to be only of order 0.001 T to provide adequate electron breaking. The corresponding external field of about 0.015 T is small enough to not cause appreciable fast particle losses or otherwise negatively impact confinement. In fact, the applied magnetic dipole (or quadrupole) field contributes to suppress instabilities. In combination with tangential neutral beam injection and axial plasma injection, the saddle coils 460 provide an additional level of control with regards to current maintenance and stability. Mirror Plugs The design of the pulsed coils 444 within the mirror plugs 440 permits the local generation of high magnetic fields (2 to 4 T) with modest (about 100 kJ) capacitive energy. For formation of magnetic fields typical of the present operation of the FRC system 10, all field lines within the formation volume are passing through the constrictions 442 at the mirror plugs 440, as suggested by the magnetic field lines in FIG. 2 and plasma wall contact does not occur. Furthermore, the mirror plugs 440 in tandem with the quasi-dc divertor magnets 416 can be adjusted so to guide the field lines onto the divertor electrodes 910, or flare the field lines in an end cusp configuration (not shown). The latter improves stability and suppresses parallel electron thermal conduction. The mirror plugs 440 by themselves also contribute to neutral gas control. The mirror plugs 440 permit a better utilization of the deuterium gas puffed in to the quartz tubes during FRC formation, as gas back-streaming into the divertors 300 is significantly reduced by the small gas conductance of the plugs (a meager 500 L/s). Most of the residual puffed gas inside the formation tubes 210 is quickly ionized. In addition, the high-density plasma flowing through the mirror plugs 440 provides efficient neutral ionization hence an effective gas barrier. As a result, most of the neutrals recycled in the divertors 300 from the FRC edge layer 456 do not return to the confinement chamber 100. In addition, the neutrals associated with the operation of the plasma guns 350 (as discussed below) will be mostly confined to the divertors 300. Finally, the mirror plugs 440 tend to improve the FRC edge layer confinement. With mirror ratios (plug/confinement magnetic fields) in the range 20 to 40, and with a 15 m length between the north and south mirror plugs 440, the edge layer particle confinement time τ∥ increases by up to an order of magnitude. Improving τ∥ readily increases the FRC particle confinement. Assuming radial diffusive (D) particle loss from the separatrix volume 453 balanced by axial loss (τ∥) from the edge layer 456, one obtains (2πrsLs)(Dns/δ)=(2πrsLsδ)(ns/τ∥), from which the separatrix density gradient length can be rewritten as δ=(Dτ∥)1/2. Here rs, Ls and ns are separatrix radius, separatrix length and separatrix density, respectively. The FRC particle confinement time is τN=[πrs2Ls<n>]/[(2πrsLs)(Dns/δ)]=(<n>/ns)(τ⊥τ∥)1/2, where τ⊥=a2/D with a=rs/4. Physically, improving τ∥ leads to increased δ (reduced separatrix density gradient and drift parameter), and, therefore, reduced FRC particle loss. The overall improvement in FRC particle confinement is generally somewhat less than quadratic because ns increases with τ∥. A significant improvement in τ∥ also requires that the edge layer 456 remains grossly stable (i.e., no n=1 flute, firehose, or other MHD instability typical of open systems). Use of the plasma guns 350 provides for this preferred edge stability. In this sense, the mirror plugs 440 and plasma gun 350 form an effective edge control system. Plasma Guns The plasma guns 350 improve the stability of the FRC exhaust jets 454 by line-tying. The gun plasmas from the plasma guns 350 are generated without azimuthal angular momentum, which proves useful in controlling FRC rotational instabilities. As such the guns 350 are an effective means to control FRC stability without the need for the older quadrupole stabilization technique. As a result, the plasma guns 350 make it possible to take advantage of the beneficial effects of fast particles or access the advanced hybrid kinetic FRC regime as outlined in this disclosure. Therefore, the plasma guns 350 enable the FRC system 10 to be operated with saddle coil currents just adequate for electron breaking but below the threshold that would cause FRC instability and/or lead to dramatic fast particle diffusion. As mentioned in the Mirror Plug discussion above, if τ∥ can be significantly improved, the supplied gun plasma would be comparable to the edge layer particle loss rate (˜1022/s). The lifetime of the gun-produced plasma in the FRC system 10 is in the millisecond range. Indeed, consider the gun plasma with density ne˜1013 cm−3 and ion temperature of about 200 eV, confined between the end mirror plugs 440. The trap length L and mirror ratio R are about 15 m and 20, respectively. The ion mean free path due to Coulomb collisions is λii˜6×103 cm and, since λii ln R/R<L, the ions are confined in the gas-dynamic regime. The plasma confinement time in this regime is τgd˜RL/2Vs˜2 ms, where Vs is the ion sound speed. For comparison, the classical ion confinement time for these plasma parameters would be τc˜0.5τii(ln R+(ln R)0.5)˜0.7 ms. The anomalous transverse diffusion may, in principle, shorten the plasma confinement time. However, in the FRC system 10, if we assume the Bohm diffusion rate, the estimated transverse confinement time for the gun plasma is τ⊥>τgd˜2 ms. Hence, the guns would provide significant refueling of the FRC edge layer 456, and an improved overall FRC particle confinement. Furthermore, the gun plasma streams can be turned on in about 150 to 200 microseconds, which permits use in FRC start-up, translation, and merging into the confinement chamber 100. If turned on around t˜0 (FRC main bank initiation), the gun plasmas help to sustain the present dynamically formed and merged FRC 450. The combined particle inventories from the formation FRCs and from the guns is adequate for neutral beam capture, plasma heating, and long sustainment. If turned on at t in the range −1 to 0 ms, the gun plasmas can fill the quartz tubes 210 with plasma or ionize the gas puffed into the quartz tubes, thus permitting FRC formation with reduced or even perhaps zero puffed gas. The latter may require sufficiently cold formation plasma to permit fast diffusion of the reversed bias magnetic field. If turned on at t<−2 ms, the plasma streams could fill the about 1 to 3 m3 field line volume of the formation and confinement regions of the formation sections 200 and confinement chamber 100 with a target plasma density of a few 1013 cm−3, sufficient to allow neutral beam build-up prior to FRC arrival. The formation FRCs could then be formed and translated into the resulting confinement vessel plasma. In this way the plasma guns 350 enable a wide variety of operating conditions and parameter regimes. Electrical Biasing Control of the radial electric field profile in the edge layer 456 is beneficial in various ways to FRC stability and confinement. By virtue of the innovative biasing components deployed in the FRC system 10 it is possible to apply a variety of deliberate distributions of electric potentials to a group of open flux surfaces throughout the machine from areas well outside the central confinement region in the confinement chamber 100. In this way radial electric fields can be generated across the edge layer 456 just outside of the FRC 450. These radial electric fields then modify the azimuthal rotation of the edge layer 456 and effect its confinement via E×B velocity shear. Any differential rotation between the edge layer 456 and the FRC core 453 can then be transmitted to the inside of the FRC plasma by shear. As a result, controlling the edge layer 456 directly impacts the FRC core 453. Furthermore, since the free energy in the plasma rotation can also be responsible for instabilities, this technique provides a direct means to control the onset and growth of instabilities. In the FRC system 10, appropriate edge biasing provides an effective control of open field line transport and rotation as well as FRC core rotation. The location and shape of the various provided electrodes 900, 905, 910 and 920 allows for control of different groups of flux surfaces 455 and at different and independent potentials. In this way a wide array of different electric field configurations and strengths can be realized, each with different characteristic impact on plasma performance. A key advantage of all these innovative biasing techniques is the fact that core and edge plasma behavior can be affected from well outside the FRC plasma, i.e. there is no need to bring any physical components in touch with the central hot plasma (which would have severe implications for energy, flux and particle losses). This has a major beneficial impact on performance and all potential applications of the HPF concept. Experimental Data—HPF Operation Injection of fast particles via beams from the neutral beam guns 600 plays an important role in enabling the HPF regime. FIGS. 16A, 16B, 16C, and 16D illustrates this fact. Depicted is a set of curves showing how the FRC lifetime correlates with the length of the beam pulses. All other operating conditions are held constant for all discharges comprising this study. The data is averaged over many shots and, therefore, represents typical behavior. It is clearly evident that longer beam duration produces longer lived FRCs. Looking at this evidence as well as other diagnostics during this study, it demonstrates that beams increase stability and reduce losses. The correlation between beam pulse length and FRC lifetime is not perfect as beam trapping becomes inefficient below a certain plasma size, i.e., as the FRC 450 shrinks in physical size not all of the injected beams are intercepted and trapped. Shrinkage of the FRC is primarily due to the fact that net energy loss (˜4 MW) from the FRC plasma during the discharge is somewhat larger than the total power fed into the FRC via the neutral beams (˜2.5 MW) for the particular experimental setup. Locating the beams at a location closer to the mid-plane of the vessel 100 would tend to reduce these losses and extend FRC lifetime. FIGS. 17A, 17B, 17C, and 17D illustrate the effects of different components to achieve the HPF regime. It shows a family of typical curves depicting the lifetime of the FRC 450 as a function of time. In all cases a constant, modest amount of beam power (about 2.5 MW) is injected for the full duration of each discharge. Each curve is representative of a different combination of components. For example, operating the FRC system 10 without any mirror plugs 440, plasma guns 350 or gettering from the gettering systems 800 results in rapid onset of rotational instability and loss of the FRC topology. Adding only the mirror plugs 440 delays the onset of instabilities and increases confinement. Utilizing the combination of mirror plugs 440 and a plasma gun 350 further reduces instabilities and increases FRC lifetime. Finally adding gettering (Ti in this case) on top of the gun 350 and plugs 440 yields the best results—the resultant FRC is free of instabilities and exhibits the longest lifetime. It is clear from this experimental demonstration that the full combination of components produces the best effect and provides the beams with the best target conditions. As shown in FIG. 1, the newly discovered HPF regime exhibits dramatically improved transport behavior. FIG. 1 illustrates the change in particle confinement time in the FRC system 10 between the conventionally regime and the HPF regime. As can be seen, it has improved by well over a factor of 5 in the HPF regime. In addition, FIG. 1 details the particle confinement time in the FRC system 10 relative to the particle confinement time in prior conventional FRC experiments. With regards to these other machines, the HPF regime of the FRC system 10 has improved confinement by a factor of between 5 and close to 20. Finally and most importantly, the nature of the confinement scaling of the FRC system 10 in the HPF regime is dramatically different from all prior measurements. Before the establishment of the HPF regime in the FRC system 10, various empirical scaling laws were derived from data to predict confinement times in prior FRC experiments. All those scaling rules depend mostly on the ratio R2/ρi, where R is the radius of the magnetic field null (a loose measure of the physical scale of the machine) and ρi is the ion larmor radius evaluated in the externally applied field (a loose measure of the applied magnetic field). It is clear from FIG. 1 that long confinement in conventional FRCs is only possible at large machine size and/or high magnetic field. Operating the FRC system 10 in the conventional FRC regime CR tends to follow those scaling rules, as indicated in FIG. 1. However, the HPF regime is vastly superior and shows that much better confinement is attainable without large machine size or high magnetic fields. More importantly, it is also clear from FIG. 1 that the HPF regime results in improved confinement time with reduced plasma size as compared to the CR regime. Similar trends are also visible for flux and energy confinement times, as described below, which have increased by over a factor of 3-8 in the FRC system 10 as well. The breakthrough of the HPF regime, therefore, enables the use of modest beam power, lower magnetic fields and smaller size to sustain and maintain FRC equilibria in the FRC system 10 and future higher energy machines. Hand-in-hand with these improvements comes lower operating and construction costs as well as reduced engineering complexity. For further comparison, FIGS. 18A, 18B, 18C, and 18D shows data from a representative HPF regime discharge in the FRC system 10 as a function of time. FIG. 18A depicts the excluded flux radius at the mid-plane. For these longer timescales the conducting steel wall is no longer as good a flux conserver and the magnetic probes internal to the wall are augmented with probes outside the wall to properly account for magnetic flux diffusion through the steel. Compared to typical performance in the conventional regime CR, as shown in FIGS. 13A, 13B, 13C, and 13D, the HPF regime operating mode exhibits over 400% longer lifetime. A representative cord of the line integrated density trace is shown in FIG. 18B with its Abel inverted complement, the density contours, in FIG. 18C. Compared to the conventional FRC regime CR, as shown in FIGS. 13A, 13B, 13C, and 13D, the plasma is more quiescent throughout the pulse, indicative of very stable operation. The peak density is also slightly lower in HPF shots—this is a consequence of the hotter total plasma temperature (up to a factor of 2) as shown in FIG. 18D. For the respective discharge illustrated in FIGS. 18A, 18B, 18C, and 18D, the energy, particle and flux confinement times are 0.5 ms, 1 ms and 1 ms, respectively. At a reference time of 1 ms into the discharge, the stored plasma energy is 2 kJ while the losses are about 4 MW, making this target very suitable for neutral beam sustainment. FIG. 19 summarizes all advantages of the HPF regime in the form of a newly established experimental HPF flux confinement scaling. As can be seen in FIG. 19, based on measurements taken before and after t=0.5 ms, i.e., t≤0.5 ms and t>0.5 ms, the confinement scales with roughly the square of the electron Temperature. This strong scaling with a positive power of Te (and not a negative power) is completely opposite to that exhibited by conventional tokomaks, where confinement is typically inversely proportional to some power of the electron temperature. The manifestation of this scaling is a direct consequence of the HPF state and the large orbit (i.e. orbits on the scale of the FRC topology and/or at least the characteristic magnetic field gradient length scale) ion population. Fundamentally, this new scaling substantially favors high operating temperatures and enables relatively modest sized reactors. While the invention is susceptible to various modifications, and alternative forms, specific examples thereof have been shown in the drawings and are herein described in detail. It should be understood, however, that the invention is not to be limited to the particular forms or methods disclosed, but to the contrary, the invention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the appended claims. In the description above, for purposes of explanation only, specific nomenclature is set forth to provide a thorough understanding of the present disclosure. However, it will be apparent to one skilled in the art that these specific details are not required to practice the teachings of the present disclosure. The various features of the representative examples and the dependent claims may be combined in ways that are not specifically and explicitly enumerated in order to provide additional useful embodiments of the present teachings. It is also expressly noted that all value ranges or indications of groups of entities disclose every possible intermediate value or intermediate entity for the purpose of original disclosure, as well as for the purpose of restricting the claimed subject matter. Systems and methods for generating and maintaining an HPF regime FRC have been disclosed. It is understood that the embodiments described herein are for the purpose of elucidation and should not be considered limiting the subject matter of the disclosure. Various modifications, uses, substitutions, combinations, improvements, methods of productions without departing from the scope or spirit of the present invention would be evident to a person skilled in the art. For example, the reader is to understand that the specific ordering and combination of process actions described herein is merely illustrative, unless otherwise stated, and the invention can be performed using different or additional process actions, or a different combination or ordering of process actions. As another example, each feature of one embodiment can be mixed and matched with other features shown in other embodiments. Features and processes known to those of ordinary skill may similarly be incorporated as desired. Additionally and obviously, features may be added or subtracted as desired. Accordingly, the invention is not to be restricted except in light of the attached claims and their equivalents.
	summary
	claims	1. An X-ray flat panel detector comprising: an effective pixel array in which a plurality of pixel electrodes are arrayed in a matrix and accumulate charges; a photoconductor which covers said effective pixel array and generates charges on the basis of incident X-rays; a bias electrode which is formed on a second surface of said photoconductor, covers an area of said pixel electrodes, and applies a bias voltage between said photoconductor and said pixel electrodes; a plurality of signal lines to read out electronic signals from said effective pixel array; a plurality of scanning lines to scan said effective pixel array; first dummy pixels which are arranged adjacent to said effective pixel array and remove noise superposed on said plurality of signal lines; second dummy pixels which are arranged adjacent to said effective pixel array and remove noise superposed on said plurality of scanning lines; a first protective electrode which is arranged in correspondence with said first dummy pixels and electrically shields said bias electrode and said plurality of signal lines or said plurality of scanning lines; and a second protective electrode which is arranged in correspondence with said second dummy pixels, disconnected from said first protective electrode and electrically shields said bias electrode and said plurality of signal lines or said plurality of scanning lines. 2. The detector according to claim 1 , further comprising a first pad to supply GND potential to said first protective electrode, and a second pad to supply GND potential to said second protective electrode. claim 1 3. The detector according to claim 1 , wherein said first protective electrode receives GND potential of a driving circuit which drives said effective pixel array; and claim 1 said second protective electrode receives GND potential of a read circuit which reads out an electrical signal from said effective pixel array via said signal line. 4. An X-ray flat panel detector comprising: an effective pixel array in which a plurality of pixel electrodes are arrayed in a matrix and accumulate charges; a photoconductor which covers said effective pixel array and generates charges on the basis of incident X-rays; a bias electrode which is formed on a second surface of said photoconductor, covers an area of said pixel electrodes, and applies a bias voltage between said photoconductor and said pixel electrodes; a plurality of signal lines to read out electronic signals from said effective pixel array; a plurality of scanning lines to scan said effective pixel array; a protective electrode which electrically shields said bias electrode and said plurality of signal lines or said plurality of scanning lines; first dummy pixels which are arranged around said protective electrode and remove noise superposed on said plurality of signal lines; and second dummy pixels which are arranged around said protective electrode and remove noise superposed on said plurality of scanning lines. 5. The detector according to claim 4 , wherein said protective electrode is disconnected at at least one portion. claim 4 6. The detector according to claim 4 , wherein said protective electrode includes at least two protective electrodes. claim 4 7. The detector according to claim 4 , wherein said protective electrode has first and second protective electrode portions which are arranged axially symmetrically about said signal line or said scanning line. claim 4 8. The detector according to claim 4 , further comprising a pad to supply GND potential to said protective electrode. claim 4 9. The detector according to claim 4 , wherein said protective electrode receives GND potential of a driving circuit which drives said effective pixel array. claim 4 10. The detector according to claim 4 , wherein said protective electrode receives GND potential of a read circuit which reads out an electrical signal from said effective pixel array via said signal line. claim 4 11. An X-ray flat panel detector comprising: an effective pixel array in which a plurality of pixel electrodes are arrayed in a matrix and accumulate charges; a photoconductor which covers said effective pixel array and generates charges on the basis of incident X-rays; a plurality of first signal lines to read out electronic signals from said effective pixel array; a plurality of first scanning lines to scan said effective pixel array; and an electrostatic dispersion wiring line which is connected directly or via a nonlinear element to at least one of said plurality of first signal lines and at least one of said plurality of first scanning lines, and distributes static electricity accumulated in at least one of said plurality of first signal lines or said plurality of first scanning lines, wherein said electrostatic dispersion wiring line has a first auxiliary wiring line to disconnect said electrostatic dispersion wiring line between a connecting portion between said electrostatic dispersion wiring line and at least one of said plurality of first signal lines and a connecting portion between said electrostatic dispersion wiring line and at least one of said first scanning lines. 12. The detector according to claim 11 , which further comprises first dummy pixels which remove noise superposed on said plurality of signal lines, second dummy pixels which remove noise superposed on said plurality of scanning lines, a second signal line to read out electronic signals from said first and second dummy pixels, and a second scanning line to scan said first and second dummy pixels; and claim 11 in which said electrostatic dispersion wiring line is connected directly or via a nonlinear element to at least one of said plurality of first signal lines, said second signal line, at least one of said plurality of first scanning lines, and said second scanning line, and has a second auxiliary wiring line to disconnect said electrostatic dispersion wiring line between a connecting portion between a connecting portion between said electrostatic dispersion wiring line and at least one of said plurality of first signal lines and a connecting portion between said electrostatic dispersion wiring line and said second signal line, or between a connecting line between said electrostatic dispersion wiring line and at least one of said plurality of first scanning lines and a connecting portion between said electrostatic dispersion wiring line and said second scanning line. 13. The detector according to claim 11 , which further comprises first dummy pixels which remove noise superposed on said plurality of signal lines, second dummy pixels which remove noise superposed on said plurality of scanning lines, a plurality of second signal lines to read out electronic signals from said first dummy pixels, and second scanning lines to scan said second dummy pixels, and in which said electrostatic dispersion wiring line has a first wiring line which is connected to at least one of said plurality of first signal lines and at least one of said plurality of second signal lines, a second wiring line which is connected to at least one of said plurality of first scanning lines, and a third wiring line which is connected to at least one of said plurality of second scanning lines. claim 11 14. The detector according to claim 13 , further comprising a resistor which connects said first, second, and third wiring lines. claim 13 15. The detector according to claim 14 , wherein said resistor has a resistance value which prevents dielectric breakdown caused by static electricity accumulated in at least one of said plurality of first signal lines or said plurality of first scanning lines. claim 14 16. The detector according to claim 13 , further comprising a third auxiliary wiring line which is connected to said first, second, and third wiring lines, and cuts off electrical connection between said wiring lines. claim 13 17. An X-ray flat panel detector comprising: an effective pixel array in which a plurality of pixel electrodes are arrayed in a matrix and accumulate charges; a photoconductor which covers said effective pixel array and generates charges on the basis of incident X-rays; a plurality of first signal lines to read out electronic signals from said effective pixel array; a plurality of first scanning lines to scan said effective pixel array; an electrostatic dispersion wiring line which is connected directly or via a nonlinear element to at least one of said plurality of first signal lines and at least one of said plurality of first scanning lines, and distributes static electricity accumulated in at least one of said plurality of first signal lines or said plurality of first scanning lines; first dummy pixels which remove noise superposed on said plurality of signal lines; second dummy pixels which remove noise superposed on said plurality of scanning lines; a plurality of second signal lines to read out electronic signals from said first dummy pixels; and second scanning lines to scan said second dummy pixels, wherein said electrostatic dispersion wiring line has a first wiring line which is connected to at least one of said plurality of first signal lines and at least one of said plurality of second signal lines, a second wiring line which is connected to at least one of said plurality of first scanning lines, and a third wiring line which is connected to at least one of said plurality of second scanning lines. 18. The detector according to claim 17 , further comprising a resistor which connects said first, second, and third wiring lines. claim 17 19. The detector according to claim 18 , wherein said resistor has a resistance value which prevents dielectric breakdown caused by static electricity accumulated in at least one of said plurality of first signal lines or said plurality of first scanning lines. claim 18 20. The detector according to claim 17 , further comprising a third auxiliary wiring line which is connected to said first, second, and third wiring lines, and cuts off electrical connection between said wiring lines. claim 17
046438688	abstract	A support arrangement is provided for the core modules of a nuclear reactor which provides support access through the control drive mechanisms of the reactor. This arrangement provides axial support of individual reactor core modules from the pressure vessel head in a manner which permits attachment and detachment of the modules from the head to be accomplished through the control drive mechanisms after their leadscrews have been removed. The arrangement includes a module support nut which is suspended from the pressure vessel head and screw threaded to the shroud housing for the module. A spline lock prevents loosening of the screw connection. An installation tool assembly, including a cell lifting and preloading tool and a torquing tool, fits through the control drive mechanism and provides lifting of the shroud housing while disconnecting the spline lock, as well as application of torque to the module support nut.
	claims	1. A method for supplying gas over a substrate in a reaction chamber wherein a substrate is placed on a pedestal, said reaction chamber having a gas-ejecting periphery on a plane, from which gas is ejected, said method comprising:supplying a first gas from the gas-ejecting periphery from a first side of the reaction chamber to a second side of the reaction chamber opposite to the first side in a horizontal direction passing through an axis of the reaction chamber so that the first gas travels over the substrate in a main stream from a first side of the substrate to a second side of the substrate opposite to the first side in a horizontal direction passing across a center of the substrate; andsupplying a second gas from the gas-ejecting periphery from sides of the reaction chamber other than the first side of the reaction chamber toward the main stream, wherein the first gas and the second gas are the same gas which is ejected in three or more directions, unevenly with respect to the gas-ejecting periphery, so that the second gas travels over the substrate in auxiliary streams from sides of the substrate other than the first side in a downstream direction of the main stream, said main stream being predominant relative to said auxiliary streams. 2. The method according to claim 1, wherein gas flow in total at the second side of the substrate is greater than gas flow in total at the first side of the substrate, and the gas flow has a flow rate gradient along the main stream. 3. The method according to claim 1, wherein the second gas is supplied from the sides, toward the center of the substrate. 4. The method according to claim 3, wherein the first and second gases are discharged from the reaction chamber through a circular duct arranged around the outer periphery of the pedestal. 5. The method according to claim 1, wherein the second gas is supplied from the sides, toward an axis passing the first and second sides of the substrate. 6. The method according to claim 5, wherein the first and second gases are discharged from the reaction chamber through a duct disposed in a vicinity of the second side of the reaction chamber. 7. The method according to claim 1, wherein the first and second gases are supplied from gas nozzles circularly arranged above and around the outer periphery of the pedestal and directed to the center of the substrate, wherein first gas nozzles supplying the first gas are disposed at the first side of the reaction chamber, and second gas nozzles supplying the second gas are disposed at the sides other than the first side of the reaction chamber. 8. The method according to claim 7, wherein the first gas nozzles have higher conductance than do the second gas nozzles. 9. The method according to claim 8, wherein the first gas nozzles are disposed at shorter intervals, have a larger diameter, and/or have a shorter nozzle length as compared with those of the second gas nozzles. 10. The method according to claim 7, wherein no gas nozzles are disposed at the second side of the reaction chamber. 11. The method according to claim 7, wherein the conductance of the first gas nozzles is about 1.5 to about 10 times higher than that of the second gas nozzles. 12. The method according to claim 7, wherein an exhaust port is disposed at the second side of the reaction chamber. 13. The method according to claim 7, wherein the first gas and the second gas are the same gas and supplied through the first and second gas nozzles via a common gas channel circularly disposed above and around the outer periphery of the pedestal. 14. The method according to claim 1, further comprising rotating the pedestal while supplying the first and second gases. 15. The method according to claim 1, wherein while supplying the first and second gases, the substrate is irradiated with UV light. 16. A UV irradiation apparatus comprising:a reaction chamber;a pedestal disposed inside the reaction chamber, for loading a substrate thereon;a UV irradiation unit disposed above the reaction chamber; anda circular flange disposed between the reaction chamber and the UV irradiation unit, said circular flange being provided with a UV transmission window disposed above the pedestal and gas nozzles,wherein the gas nozzles are provided along the circumference of the circular flange and directed to a center of a substrate when loaded and comprise first gas nozzles for supplying a first gas disposed at a first side of the flange and second gas nozzles for supplying a second gas disposed at sides other than the first side of the flange so that the first gas travels over the substrate in a main stream from a first side of the substrate to a second side of the substrate opposite to the first side in a horizontal direction passing across a center of the substrate, and the second gas travels over the substrate in auxiliary streams from sides of the substrate other than the first side in a downstream direction of the main stream, said main stream being predominant relative to said auxiliary streams, wherein the first gas and the second gas are the same gas which can be ejected in three or more directions, unevenly with respect to the circumference of the flange, to form the main stream and the auxiliary streams, wherein the first gas nozzles have higher conductance than do the second gas nozzles. 17. The UV irradiation apparatus according to claim 16, wherein the first gas nozzles are disposed at shorter intervals, have a larger diameter, and/or have a shorter nozzle length as compared with those of the second gas nozzles. 18. The UV irradiation apparatus according to claim 16, wherein no gas nozzles are disposed at the second side of the reaction chamber, and an exhaust port is disposed at the second side of the reaction chamber. 19. The UV irradiation apparatus according to claim 16, wherein the conductance of the first gas nozzles is about 1.5 to about 10 times higher than that of the second gas nozzles. 20. The UV irradiation apparatus according to claim 16, wherein the pedestal is rotatable.
	claims	1. An ion beam apparatus comprising an ion beam optical system including an ion source, an objective lens for focusing an ion beam emitted from said ion source, and a scanning and deflecting unit for scanning said ion beam on a sample, a detector for detecting secondary particles generated from the sample under the irradiation of said ion beam, and a control unit for controlling said ion beam optical system, wherein said control unit controls to change a focusing condition of said objective lens in accordance with a current value of said ion beam when section processing of said sample is executed; wherein when the current value of said ion beam is less than the predetermined value, said control unit sets the focusing condition of said objective lens so that a Gauss image plane of said ion beam is more flush with a surface of said sample than the case that the current value of said ion beam is not less than the predetermined value; and wherein when the current value of said ion beam is not less than the predetermined value, said control unit changes the focusing condition of said objective lens to set the focusing condition of said objective lens so that a plane of said ion beam on which a least circle of confusion is formed is more flush with a surface of said sample than the case that the current value of said ion beam is less than the predetermined value. 2. An ion beam apparatus according to claim 1 , wherein said objective lens includes an electrostatic lens and said control unit performs switching between a focusing/processing ion beam and an edge processing ion beam by switching lens voltage of said objective lens. claim 1 3. An ion beam apparatus according to claim 1 , further comprising a restriction diaphragm having a restriction aperture with an opening of circular form or a mask having an opening of desired form inclusive of a circle, said opening having an opening area for permitting current of said ion beam to have a value not less than said predetermined value. claim 1 4. An ion beam apparatus according to claim 1 , further comprising a restriction diaphragm having a restriction aperture with an opening of circular form and said least circle of confusion is formed at a position which substantially coincides with the surface of said sample. claim 1 5. An ion beam apparatus according to claim 1 , further comprising a restriction diaphragm comprising a mask having an opening of a desired form inclusive of a circle, said ion beam is an edge processing ion beam having, at the sample surface position, a sectional form that is analogous to the form of opening of said mask in a direction vertical to an optical axis, and said control unit has the function of forming an edge processing ion beam by controlling a lens voltage of an electrostatic lens forming said objective lens and the function of forming an axis-alignment focusing/processing ion beam for high image resolution by changing the lens voltage of said electrostatic lens on the basis of conditions for formation of said edge processing ion beam. claim 1 6. An ion beam apparatus according to claim 1 , wherein said control unit controls said ion beam optical system such that said ion beam is formed as an observation ion beam during sample observation and process region setting and said ion beam is formed as an edge processing ion beam during sample processing. claim 1 7. An ion beam apparatus according to claim 1 , wherein said control unit includes a memory for storing a relation between a value characteristic of said ion beam and a control value of said ion beam optical system. claim 1 8. An ion beam apparatus according to claim 7 , wherein the characteristic value of said ion beam is at least one of beam current, beam diameter and beam aperture angle of said ion beam. claim 7 9. An ion beam apparatus according to claim 6 , wherein said control unit stores, as a difference correction amount, a difference in irradiation position on the sample between said edge processing ion beam and said observation ion beam and has the function of correcting the ion beam irradiation position by using said difference correction amount such that the irradiation position of said edge processing ion beam coincides with that of said observation ion beam on the sample. claim 6 10. An ion beam apparatus according to claim 6 , further comprising an image memory for saving an observation image of the sample observed using said observation ion beam, means for setting a process region at a desired position of the sample by using the observation image saved in said image memory and display means for displaying said set process region and said saved observation image in an overlapping fashion. claim 6 11. An ion beam apparatus according to claim 4 , further comprising means for setting a scanning region of said ion beam by subtracting from the set process region an amount corresponding to a precedently determined beam radius of said ion beam. claim 4 12. An ion beam apparatus according to claim 1 , further comprising a display for indicating whether the ion beam irradiated on the sample is an observation ion beam or a processing ion beam and a display for indicating, when the ion beam irradiated on the sample is said processing ion beam, whether said processing ion beam is a focusing/processing ion beam or an edge processing ion beam. claim 1 13. An ion beam apparatus according to claim 5 , further comprising an image memory for saving an observation image of the sample observed using an observation ion beam, means for displaying a position of the optical axis of said edge processing ion beam and a region referenced to the optical axis and scheduled to be processed by projecting said edge processing ion beam upon the sample in a fashion of overlapping with said saved observation image, and means for setting the process region by designating the position of optical axis of said edge processing ion beam such that said region scheduled for processing coincides with a desired position. claim 5 14. An ion beam apparatus according to claim 1 , further comprising transport means for transferring an extractive sample obtained by separating part of the sample to a position different from an extractive position and an extractive sample state for carrying said extractive sample transferred by said transport means. claim 1 15. An ion beam apparatus according to claim 14 , wherein said control unit includes desired form processing control means for processing the form of said extractive sample into a desired form including at least one of elongated lamina, rectangular prism, triangular prism and gear. claim 14 16. An ion beam apparatus according to claim 1 , further comprising a deposition gas source for supplying a raw material gas for formation of a deposition film in said ion beam irradiation region on the sample, said control unit including beam adjusting means for forming an edge deposition processing ion beam assuming a beam focusing state similar to that of said edge processing ion beam. claim 1 17. An ion beam apparatus according to claim 3 , further comprising at least one upper intermediate focusing means for focusing said ion beam between said objective lens and said restriction diaphragm. claim 3 18. An ion beam apparatus according to claim 3 , further comprising an illuminating means and at least one lower intermediate focusing means for focusing said ion beam between said restriction diaphragm and said illuminating means. claim 3 19. An ion beam apparatus according to claim 1 , wherein said control unit includes brightness change detecting means for detecting a change in brightness of an ion microscope image observed during processing and end point detecting means for stopping the processing at the time that the brightness change is detected. claim 1 20. An ion beam apparatus according to claim 1 , further comprising output gain adjusting means for adjusting the output gain of said detector in accordance with the magnitude of beam current of said processing ion beam. claim 1 21. An ion beam apparatus according to claim 1 , wherein said apparatus comprises a plurality of ion beam optical systems and optical axes of at least two ion beam optical systems cross each other at one point. claim 1 22. An ion beam apparatus according to claim 21 , wherein said apparatus comprises an ion beam optical system for forming only an edge processing ion beam and an ion beam optical system for forming an observation ion beam and a focusing/processing ion beam. claim 21 wherein said control unit controls to change conditions of said objective lens in accordance with one of a case that a current value of said ion beam is less than a predetermined and a case that the current value of said ion beam is not less than the predetermined values, when section processing of said sample is executed; wherein when the current value of said ion beam is less than the predetermined value, a condition of said ion beam optical system is changed so that an image of said ion source is formed on a surface of said sample; and wherein when the current value of said ion beam is not less than the predetermined value, a condition of said ion beam optical system is changed so that an image of said opening of said mask is formed on the surface of said sample. 23. A sample processing method for executing section processing of a sample by irradiating a sample with an ion beam emitted from an ion source through an ion beam optical system, comprising the steps of: changing into and processing said sample under a condition of said ion beam optical system in which a position of a Gauss image of said ion beam is substantially flush with a surface of said sample, when a current value of said ion beam is less than a predetermined value; and changing into and processing said sample under a condition of said ion beam optical system in which a position of a least circle of confusion of said ion beam is substantially flush with the surface of said sample, when a current value of said ion beam is not less than said predetermined value. 24. A sample processing method for executing section processing of a sample by irradiating a sample with an ion beam emitted from an ion source through an ion beam optical system including a mask having an opening formed in a desired shape, comprising the steps of: changing into and processing said sample under a condition of said ion beam optical system in which an image of said ion source is formed on a surface of said sample, when a current value of said ion beam optical system is less than a predetermined value; and changing into and processing said sample under a condition of said ion beam optical system in which an image of said opening of said mask is formed on the surface of the sample, when a current value of said ion beam is not less than said predetermined value. 25. An ion beam apparatus comprising an ion beam optical system including an ion source, an objective lens for focusing an ion beam emitted from said ion source, a scanning and deflecting unit for scanning said ion beam on a sample, and a mask having an opening for forming said ion beam emitted from said ion source in a desired shape, a detector for detecting secondary particles generated from the sample under the irradiation of said ion beam, and a control unit for controlling said ion beam optical system.
	claims	1. A method of producing a diffraction grating with a phase imaging apparatus comprising a first diffraction grating for forming a periodic pattern from X-rays emitted from an X-ray source and a second diffraction grating for interfering with the periodic pattern of the first diffraction grating, the second diffraction grating including a plurality of unit diffraction gratings, comprising:generating a moire by interfering between a plurality of unit diffraction gratings of the second diffraction grating and the periodic pattern formed by the first diffraction gratin; andaligning at least one of the plurality of unit diffraction gratings with respect to another of the plurality of unit diffraction gratings by relatively rotating the at least one of the plurality of unit diffraction gratings with respect to the another unit diffraction grating of the plurality of unit diffraction gratings based on a status of the moire generated. 2. The method of producing a diffraction grating as recited in claim 1, whereinthe plurality of unit diffraction gratings includes a first unit diffraction grating and a second unit diffraction grating, andrelatively rotating the at least one of the plurality of unit diffraction gratings includes aligning extending directions of the first unit diffraction grating and the second unit diffraction grating by relatively rotating the first unit diffraction grating with respect to the second unit diffraction grating based on a period of a first moire generated by the first unit diffraction grating and the periodic pattern and a period of a second moire generated by the second unit diffraction grating and the periodic pattern. 3. The method of producing a diffraction grating as recited in claim 2, further comprising fixing the first unit diffraction grating with respect to a substrate of the second diffraction grating,wherein relatively rotating the first unit diffraction grating with respect to the second unit diffraction grating includes aligning extending directions of absorption portions of the first unit diffraction grating and the second unit diffraction grating by relatively rotating the second unit diffraction grating with respect to the substrate with the first unit diffraction grating fixed to the substrate; andwherein the method further comprises fixing the second unit diffraction grating with respect to the substrate with the extending directions of the absorption portions of the first unit diffraction grating and the second unit diffraction grating aligned. 4. The method of producing a diffraction grating as recited in claim 3,wherein relatively rotating the first unit diffraction grating with respect to the second unit diffraction grating comprises rotating the second unit diffraction grating in a state in which the substrate of the second diffraction grating and the first unit diffraction grating are fixed. 5. The method of producing a diffraction grating as recited in claim 3,wherein relatively rotating the first unit diffraction grating with respect to the second unit diffraction grating comprises rotating the substrate and the first unit diffraction grating together in a state in which the second unit diffraction grating is fixed. 6. The method of producing a diffraction grating as recited in claim 3, wherein the plurality of unit diffraction gratings further includes a third unit diffraction grating and the method further comprises:with the first and second unit diffraction gratings fixed to the substrate, relatively rotating the third unit diffraction grating with respect to the first unit diffraction grating and the second unit diffraction grating in a state in which the first unit diffraction grating and the second unit diffraction grating are fixed to the substrate; andfixing the third unit diffraction grating with respect to the substrate after relatively rotating the third unit diffraction grating so that the extending directions of the absorption portions of the first, second and third unit diffraction gratings are aligned with the first, second and third unit diffraction gratings fixed with respect to the substrate. 7. The method of claim 1, wherein the second diffraction grating is an absorption grating. 8. The method of claim 1, wherein the second diffraction grating is a phase grating. 9. The method of claim 2, wherein the second diffraction grating is an absorption grating. 10. The method of claim 2, wherein the second diffraction grating is a phase grating. 11. The method of claim 2, further comprising fixing the first unit diffraction grating and the second unit diffraction grating to a substrate of the second diffraction grating so that absorption portions of the first unit diffraction grating and the second unit diffraction grating extend in a first direction with respect to the substrate. 12. The method of claim 11, wherein the first unit diffraction grating and the second unit diffraction grating are adjacent to each other in the first direction on the substrate. 13. The method of claim 11, wherein the first unit diffraction grating and the second unit diffraction grating are adjacent to each other in a second direction that is perpendicular to the first direction on the substrate. 14. The method of claim 11, wherein the first unit diffraction grating and the second unit diffraction grating are neither adjacent to each other in the first direction on the substrate nor adjacent to each other in a second direction that is perpendicular to the first direction on the substrate. 15. The method of claim 2, wherein relatively rotating the first unit diffraction grating with respect to the second unit diffraction grating comprises matching the periods of the first and second moires by adjusting at least one of the periods of the first and second moires. 16. The method of claim 2, wherein relatively rotating the first unit diffraction grating with respect to the second unit diffraction grating comprises relatively rotating at least one of the first unit diffraction grating and the second unit diffraction grating with respect to the periodic pattern. 17. The method of claim 16, further comprising generating a self-image as the periodic pattern by irradiating X-rays onto the first grating. 18. The method of claim 17, further comprising arranging the first unit diffraction grating and the second unit diffraction grating on a substrate of the second diffraction grating that is spaced a predetermined distance away from the first grating.
	summary
	summary
	abstract	A fuel assembly for a boiling-water reactor has a water channel and a fuel assembly base, made from a sieve plate and a frame section enclosing the same. The water channel supports a plug with a bore running therethrough, at the lower end thereof, to which the fuel assembly base is fixed. The fuel assembly further comprises an opening through the sieve plate, a skirt, formed on the underside of the plug, surrounding the bore, extending into the opening in the sieve plate, a bush, provided with a first and a second longitudinal section, whereby the first longitudinal section extends from the underside of the sieve plate into the opening in a rotationally-fixed manner and a radial shoulder is provided between the two sections which contacts the underside of the sieve plate. A threaded section of a screw extends through the bush which engages in a thread in the bore in the plug.
053346297	claims	1. A visible light actuated apparatus comprising: a source of visible light having the capability of selectively emitting either of at least one first wavelength of visible light or at least one second wavelength of visible light, said at least one first wavelength of visible light and said at least one second wavelength of visible light being emitted within the spectrum of visible light of between 400 nm to 700 nm and at an amplitude sufficient to effect a pH change; a pH dependent dye solution, disposed to receive said at least one first wavelength of visible light or said at least one second wavelength of visible light, having the property of being responsive to said at least one first wavelength of visible light or said at least one second wavelength of visible light to change its pH to either of two discrete pH values within a pH range of 3 to 11, respectively; and a polyelectrolyte fiber, disposed in said pH dependent dye solution, having the property to change its volume in response to one of said two discrete pH values of said pH dependent dye solution to produce a selective first physical displacement and to reversibly change its volume in response to the other of said two discrete pH values of said pH dependent dye solution to produce a selective reversible second physical displacement. radiating at least one first wavelength of visible light or at least one second wavelength of visible light from a source of at least one first wavelength of visible light and at least one second wavelength of visible light, said at least one first wavelength of visible light and said at least one second wavelength of visible light being emitted within the spectrum of visible light of between 400 nm to 700 nm and at an amplitude sufficient to effect a pH change; providing a pH dependent dye solution, disposed to receive said at least one first wavelength of visible light or said at least one second wavelength of visible light, having the property of being responsive to said at least one first wavelength or said at least one second wavelength of visible light to change its pH within a pH range of 3 to 11; immersing a polyelectrolyte fiber in said pH dependent dye solution, said polyelectrolyte fiber having the property to change its volume in response to one of said two discrete pH values of said pH dependent dye solution to produce a selective first physical displacement and to reversibly change its volume in response to the other of said two discrete pH values of said pH dependent dye solution to produce a selective reversible second physical displacement; directly radiating said at least one first wavelength of visible light or said at least one second wavelength of visible light from said source of said at least one first wavelength of visible light and said at least one second wavelength of visible light to impinge on said pH dependent dye solution; changing the pH in said pH dependent dye solution to one of said two discrete pH values by said directly radiating; changing the volume of said polyelectrolyte fiber in response to said one of said two discrete pH values to produce a selective first physical displacement; changing the pH in said pH dependent dye solution to the other of said two discrete pH values by said directly radiating; and reversibly changing the volume of said polyelectrolyte fiber in response to the other of said two discrete pH values of said pH dependent dye solution to produce a selective reversible second physical displacement. a source of visible light having the capability of selectively emitting either of at least one first wavelength of visible light or at least one second wavelength of visible light, said at least one first wavelength of visible light and said at least one second wavelength of visible light being emitted within the spectrum of visible light of between 400 nm to 700 nm and at an amplitude sufficient to effect a pH change; means for defining a first chamber and a second chamber having a displaceable wall in communication with at least one of the chambers, the defining means being provided with a portion transparent to said at least one first wavelength of visible light and at least one said second wavelength of visible light and being further provided with at least one check valve arranged in communication with said second chamber to assure a pumping of said fluid in response to said selective displacement of said displaceable wall; a pH dependent dye solution, disposed in said first chamber to receive said at least one first wavelength of visible light or at least one said second wavelength of visible light, having the property of being responsive to said at least one first wavelength of visible light or said at least one second wavelength of visible light to change its pH to either of two discrete pH values within a pH range of 3 to 11, respectively; and a polyelectrolyte fiber, disposed in said pH dependent dye solution and coupled to said displaceable wall, said polyelectrolyte fiber having the property to change its volume in response to one of said two discrete pH values of said pH dependent dye solution to produce a selective first physical displacement of said wall and to reversibly change its volume in response to the other of said two discrete pH values of said pH dependent dye solution to produce a selective reversible second physical displacement of said wall. a flexible pod containing said pH dependent dye solution and said polyelectrolyte fiber, said polyelectrolyte fiber, being attached at opposite ends thereof to an inner wall of said pod and said optical fiber optically communicating with said pH dependent dye solution in said pod. at least two segments joined together by a pin to permit relative rotational motion therebetween and having at least one said pod connected to said two segments to impart said relative rotational motion therebetween. providing at least one optical fiber to transmit said at least one first wavelength of visible light or said at least one second wavelength of visible light from said source of said at least one first wavelength of visible light and said at least one second wavelength of visible light to assure said radiating. providing a pod to contain said pH dependent dye solution and said polyelectrolyte fiber, said polyelectrolyte fiber, being attached at opposite ends thereof to an inner wall of said pod and said optical fiber optically communicating with said pH dependent dye solution in said pod. a flexible pod containing said pH dependent dye solution and said polyelectrolyte fiber, said polyelectrolyte fiber, being attached at opposite ends thereof to an inner wall of said pod and said optical fiber optically communicating with said pH dependent dye solution in said pod. providing at least one optical fiber to transmit said at least one first wavelength of visible light or at least one said second wavelength of visible light from said source of said at least one first wavelength of visible light and said at least one second select wavelength of visible light to assure said radiating. providing a pod to contain said pH dependent dye solution and said polyelectrolyte fiber, said polyelectrolyte fiber, being attached at opposite ends thereof to an inner wall of said pod and said optical fiber optically communicating with said pH dependent dye solution in said pod. a source of visible light having the capability of selectively emitting either of at least one first wavelength of visible light or at least one second wavelength of visible light, said at least one first wavelength of visible light and said at least one second wavelength of visible light being emitted within the spectrum of visible light of between 400 nm to 700 nm and at an amplitude sufficient to effect a pH change; a pH dependent dye solution, disposed to receive said at least one first wavelength of visible light or said at least one second wavelength of visible light, having the property of being responsive to said at least one first wavelength of visible light or said at least one second wavelength of visible light to change its pH to either of two discrete pH values within a pH range of 3 to 11, respectively; and a polyelectrolyte gel, disposed in said pH dependent dye solution, having the property to change its volume in response to one of said two discrete pH values of said pH dependent dye solution to produce a selective first physical displacement and to reversibly change its volume in response to the other of said two discrete pH values of said pH dependent dye solution to produce a selective reversible second physical displacement. radiating at least one first wavelength of visible light or at least one second wavelength of visible light from a source of at least one first wavelength of visible light and at least one second wavelength of visible light, said at least one first wavelength of visible light and said at least one second wavelength of visible light being emitted within the spectrum of visible light of between 400 nm to 700 nm and at an amplitude sufficient to effect a pH change; providing a pH dependent dye solution, disposed to receive said at least one first wavelength of visible light or said at least one second wavelength of visible light, having the property of being responsive to said at least one first wavelength or said at least one second wavelength of visible light to change its pH within a pH range of 3 to 11; immersing a polyelectrolyte gel in said pH dependent dye solution, said polyelectrolyte gel having the property to change its volume in response to one of said two discrete pH values of said pH dependent dye solution to produce a selective first physical displacement and to reversibly change its volume in response to the other of said two discrete pH values of said pH dependent dye solution to produce a selective reversible second physical displacement; directly radiating said at least one first wavelength of visible light or said at least one second wavelength of visible light from said source of said at least one first wavelength of visible light and said at least one second wavelength of visible light to impinge on said pH dependent dye solution; changing the pH in said pH dependent dye solution to one of said two discrete pH values by said directly radiating; changing the volume of said polyelectrolyte gel in response to said one of said two discrete pH values to produce a selective first physical displacement; changing the pH in said pH dependent dye solution to the other of said two discrete pH values by said directly radiating; and reversibly changing the volume of said polyelectrolyte gel in response to the other of said two discrete pH values of said pH dependent dye solution to produce a selective reversible second physical displacement. a source of visible light having the capability of selectively emitting either of at least one first wavelength of visible light or at least one second wavelength of visible light, said at least one first wavelength of visible light and said at least one second wavelength of visible light being emitted within the spectrum of visible light of between 400 nm to 700 nm and at an amplitude sufficient to effect a pH change; means for defining a first chamber and a second chamber having a displaceable wall in communication with at least one of the chambers, the defining means being provided with a portion transparent to said at least one first wavelength of visible light and at least one said second wavelength of visible light and being further provided with at least one check valve arranged in communication with said second chamber to assure a pumping of said fluid in response to said selective displacement of said displaceable wall; a pH dependent dye solution, disposed in said first chamber to receive said at least one first wavelength of visible light or at least one said second wavelength of visible light, having the property of being responsive to said at least one first wavelength of visible light or said at least one second wavelength of visible light to change its pH to either of two discrete pH values within a pH range of 3 to 11, respectively; and a polyelectrolyte gel, disposed in said pH dependent dye solution and coupled to said displaceable wall, said polyelectrolyte gel having the property to change its volume in response to one of said two discrete pH values of said pH dependent dye solution to produce a selective first physical displacement of said wall and to reversibly change its volume in response to the other of said two discrete pH values of said pH dependent dye solution to produce a selective reversible second physical displacement of said wall. a flexible pod containing said pH dependent dye solution and said polyelectrolyte gel, said polyelectrolyte gel, being attached at opposite ends thereof to an inner wall of said pod and said optical fiber optically communicating with said pH dependent dye solution in said pod. at least two segments joined together by a pin to permit relative rotational motion therebetween and having at least one said pod connected to said two segments to impart said relative rotational motion therebetween. providing at least one optical fiber to transmit said at least one discrete wavelength of electromagnetic radiation from a source of said at least one discrete wavelength of electromagnetic radiation to assure said radiating. providing a pod to contain said pH dependent dye solution and said polyelectrolyte gel, said polyelectrolyte gel, being attached at opposite ends thereof to an inner wall of said pod and said optical fiber optically communicating with said pH dependent dye solution in said pod. a flexible pod containing said pH dependent dye solution and said polyelectrolyte gel, said polyelectrolyte gel, being attached at opposite ends thereof to an inner wall of said pod and said optical fiber optically communicating with said pH dependent dye solution in said pod. providing at least one optical fiber to transmit said at least one first wavelength of visible light or at least one said second wavelength of visible light from said source of said at least one first wavelength of visible light and said at least one second select wavelength of visible light to assure said radiating. providing a pod to contain said pH dependent dye solution and said polyelectrolyte gel, said polyelectrolyte gel, being attached at opposite ends thereof to an inner wall of said pod and said optical fiber optically communicating with said pH dependent dye solution in said pod. 2. An apparatus according to claim 1 in which said pH dependent dye solution has an acid dissociation constant pKa within plus or minus 1 pH unit of the pH null point of said polyelectrolyte fiber. 3. An apparatus according to claim 2 in which said at least one first wavelength of visible light and said at least one second wavelength of visible light emitted by said source of visible light are predetermined to change said two discrete pH values of said pH dependent dye solution to be greater than and less than said pH null point of said polyelectrolyte fiber, respectively. 4. An apparatus according to claim 1 in which said pH polyelectrolyte fiber is polyvinyl alcohol-polyacrylic acid (PVA-PAA). 5. An apparatus according to claim 1 in which said polyelectrolyte fiber is polyvinyl alcohol-polyacrylic acid-polyallylamine. 6. An apparatus according to claim 1 in which said polyelectrolyte fiber is protein polyelectrolytes. 7. An apparatus according to claim 3 in which said polyelectrolyte fiber is poly methacrylic acid. 8. An apparatus according to claim 3 in which said pH polyelectrolyte fiber is polyvinyl alcohol-polyacrylic acid (PVA-PAA). 9. An apparatus according to claim 3 in which said polyelectrolyte fiber is polyvinyl alcohol-polyacrylic acid-polyallylamine. 10. An apparatus according to claim 3 in which said polyelectrolyte fiber is protein polyelectrolytes. 11. A method actuated by visible light comprising: 12. A method according to claim 11 in which the providing of said pH dependent dye solution is the selecting of said pH dependent dye solution to have an acid dissociation constant pKa within plus or minus 1 pH unit of the pH null point of said polyelectrolyte fiber. 13. A method according to claim 12 in which said at least one first wavelength of visible light and said at least one second wavelength of visible light radiated by said source of visible light are predetermined to change said two discrete pH values of said pH dependent dye solution to be greater than and less than said pH null point of said polyelectrolyte fiber, respectively. 14. A method according to claim 11 in which said pH polyelectrolyte fiber is polyvinyl alcohol-polyacrylic acid (PVA-PAA). 15. A method according to claim 11 in which said polyelectrolyte fiber is polyvinyl alcohol-polyacrylic acid-polyallylamine. 16. A method according to claim 11 in which said polyelectrolyte fiber is protein polyelectrolytes. 17. A method according to claim 13 in which said polyelectrolyte fiber is poly methacrylic acid. 18. A method according to claim 13 in which said pH polyelectrolyte fiber is polyvinyl alcohol-polyacrylic acid (PVA-PAA). 19. A method according to claim 13 in which said polyelectrolyte fiber is polyvinyl alcohol-polyacrylic acid-polyallylamine. 20. A method according to claim 13 in which said polyelectrolyte fiber is protein polyelectrolytes. 21. An apparatus for pumping a fluid in response to visible light comprising: 22. An apparatus according to claim 21 in which said pH dependent dye solution has an acid dissociation constant pKa within plus or minus 1 pH unit of the pH null point of said polyelectrolyte fiber. 23. An apparatus according to claim 1 in which said source of visible light having the capability of selectively emitting either of at least one first wavelength of visible light or at least one second wavelength of visible light includes at least one optical fiber oriented to direct said at least one first wavelength or said at least one second wavelength of visible light on said pH dependent dye solution to effect a change in the pH in said pH dependent dye solution and a consequent change in volume in said polyelectrolyte fiber. 24. An apparatus according to claim 23 further including: 25. An apparatus according to claim 24 further including: 26. A method according to claim 11 further including: 27. A method according to claim 26 further including: 28. An apparatus according to claim 22 in which said at least one first wavelength of visible light and said at least one second wavelength of visible light emitted by said source of visible light are predetermined to change said two discrete pH values of said pH dependent dye solution to be greater than and less than said pH null point of said polyelectrolyte fiber or gel, respectively. 29. An apparatus according to claim 1 in which said polyelectrolyte fiber is poly methacrylic acid. 30. A method according to claim 11 in which said polyelectrolyte fiber is poly methacrylic acid. 31. An apparatus according to claim 28 in which said source of visible light having the capability of selectively emitting either of at least one first wavelength of visible light or at least one second wavelength of visible light includes at least one optical fiber oriented to direct said at least one first wavelength of visible light or said at least one second wavelength of visible light on said pH dependent dye solution to effect a change in the pH in said pH dependent dye solution and a consequent change in volume in said polyelectrolyte fiber. 32. An apparatus according to claim 31 further including: 33. A method according to claim 13 further including: 34. A method according to claim 33 further including: 35. A visible light actuated apparatus comprising: 36. An apparatus according to claim 35 in which said pH dependent dye solution has an acid dissociation constant pKa within plus or minus 1 pH unit of the pH null point of said polyelectrolyte gel. 37. An apparatus according to claim 35 in which said at least one first wavelength of visible light and said at least one second wavelength of visible light radiated by said source of visible light are predetermined to change said two discrete pH values of said pH dependent dye solution to be greater than and less than said pH null point of said polyelectrolyte gel, respectively. 38. An apparatus according to claim 35 in which said polyelectrolyte gel is polymerized isopropylacrylamide. 39. An apparatus according to claim 36 in which said polyelectrolyte gel is poly methacrylic acid. 40. An apparatus according to claim 36 in which said polyelectrolyte gel is polymerized isopropylacrylamide. 41. A method actuated by visible light comprising: 42. A method according to claim 41 in which the providing of said pH dependent dye solution is the selecting of said pH dependent dye solution to have an acid dissociation constant pKa within plus or minus 1 pH unit of the pH null point of said polyelectrolyte gel. 43. A method according to claim 42 in which said at least one first wavelength of visible light and said at least one second wavelength of visible light radiated by said source of visible light are predetermined to change said two discrete pH values of said pH dependent dye solution to be greater than and less than said pH null point of said polyelectrolyte gel, respectively. 44. A method according to claim 41 in which said polyelectrolyte gel is polymerized isopropylacrylamide. 45. A method according to claim 43 in which said polyelectrolyte gel is poly methacrylic acid. 46. A method according to claim 43 in which said polyelectrolyte gel is polymerized isopropylacrylamide. 47. An apparatus for pumping a fluid in response to visible light comprising: 48. An apparatus according to claim 47 in which said pH dependent dye solution has an acid dissociation constant pKa within plus or minus 1 pH unit of the pH null point of said polyelectrolyte gel. 49. An apparatus according to claim 35 in which the at least one discrete wavelength of electromagnetic radiation source includes at least one optical fiber oriented to direct said at least one discrete wavelength of electromagnetic radiation to impinge on said pH dependent dye solution to effect a change in the pH in said pH dependent dye solution and a consequent change in volume in said polyelectrolyte gel and thereby power said selective displacement. 50. An apparatus according to claim 49 further including: 51. An apparatus according to claim 50 further including: 52. A method according to claim 41 further including: 53. A method according to claim 52 further including: 54. An apparatus according to claim 47 in which the at least one discrete wavelength of electromagnetic radiation source includes at least one optical fiber oriented to direct said at least one discrete wavelength of electromagnetic radiation through to impinge on said pH dependent dye solution to effect a change in the pH in said pH dependent dye solution and a consequent change in volume in said polyelectrolyte gel and thereby power said selective displacement of said moveable wall to assure said pumping of said fluid. 55. An apparatus according to claim 35 in which said polyelectrolyte gel is poly methacrylic acid. 56. A method according to claim 41 in which said polyelectrolyte gel is poly methacrylic acid. 57. An apparatus according to claim 43 in which said source of visible light having the capability of selectively emitting either of at least one first wavelength of visible light or at least one second wavelength of visible light includes at least one optical fiber oriented to direct said at least one first wavelength of visible light or said at least one second wavelength of visible light on said pH dependent dye solution to effect a change in the pH in said pH dependent dye solution and a consequent change in volume in said polyelectrolyte gel. 58. An apparatus according to claim 57 further including: 59. A method according to claim 41 further including: 60. A method according to claim 43 further including:
	claims	1. A method of measuring a semiconductor device comprising steps of:providing a silicon-on-insulator (SOI) substrate with at least a body-tied (BT) SOI device and a body-tied (BT) dummy device for measurement, where in the BT dummy device comprises a first conductive type source/drain heavily doped region and a dummy gate, and the dummy is not positioned on the first conductive type source/drain heavily doped region;measuring scattering parameters (S-parameters) and tunneling currents (Igb) of the BT SOI device and the BT dummy device, respectively;subtracting Igb of the BT dummy device from that of the BT SOI device to obtain Igb of a floating body (FB) SOI device;filtering characteristics of the BT dummy device out to extract S-parameters of the FB SOI device; andanalyzing the S-parameters of the FB SOI device to obtain gate-related capacitances (Cgb) of the FB SOI device. 2. The method of claim 1, wherein the BT SOI device and the BT dummy device are simultaneously formed on the SOI substrate by same processes. 3. The method of claim 1, wherein the SOI substrate comprises a plurality of second conductive type well. 4. The method of claim 3, wherein the BT SOI device comprises:a gate structure formed on the second conductive type well;at least a first conductive type source/drain heavily doped region formed in the second conductive type well;a second conductive type heavily doped region formed in the SOI substrate, the second conductive type heavily doped region being isolated from the first conductive type source/drain heavily doped region by the second conductive type well; anda body electrically connected to a circuit. 5. The method of claim 4, wherein the gate structure comprises a first part and a second part perpendicular to the first part, and the second part is formed across the second conductive type well. 6. The method of claim 5, wherein the first part of the gate structure comprises a first conductive type region and a second conductive type region, the first conductive type region is proximal to the first conductive type source/drain heavily doped region and the second conductive type region is adjacent to the second conductive type heavily doped region. 7. The method of claim 6, wherein the gate structure is a T-shaped gate structure. 8. The method of claim 7, wherein the BT dummy device comprises:a second conductive type heavily doped region; anda body electrically connected to a circuit; whereinthe dummy gate is positioned on the second conductive type well and comprises a first conductive type region and a second conductive type region, the first conductive type region is proximal to the first conductive type source/drain heavily doped region and the second conductive type region is proximal to the second conductive type heavily doped region. 9. The method of claim 6, wherein the gate structure is a H-shaped gate structure, and the first parts of the H-shaped gate structure are positioned parallel to each other and on opposite ends of the second part. 10. The method of claim 9, wherein the BT dummy device comprise:a second conductive type heavily doped region; anda body electrically connected to a circuit; whereinthe dummy gates is a pair of dummy gates positioned parallel to each on the second conductive type well and respectively comprises a first conductive type region and a second conductive type region, the first conductive type region is proximal to the first conductive type source/drain heavily doped region and the second conductive type region is proximal to the second conductive type heavily doped region. 11. The method of claim 1, wherein the BT SOI device and the BT dummy device are constructed in a radio frequency (RF) test key. 12. The method of claim 1, wherein the SOI substrate is a device wafer or a monitor wafer. 13. A semiconductor device comprising:a SOI substrate having a second conductive type well;a first conductive type source/drain heavily doped region formed in the second conductive type well;a second conductive type heavily doped region formed in the SOI substrate, the second conductive type heavily doped region being isolated from the first conductive type source/drain heavily doped region by the second conductive type well;a dummy gate positioned on the first conductive type well, the dummy gate being not across the first conductive type source/drain heavily doped region; anda body-tied (BT) body electrically connected to a circuit. 14. The semiconductor device of claim 13, wherein the SOI substrate sequentially comprises a substrate, a buried oxide (BOX) layer and a first conductive type doped silicon layer. 15. The semiconductor device of claim 13, wherein the dummy gate comprises a first conductive type region and a second conductive type region, the first conductive type region is proximal to the first conductive type source/drain heavily doped region and the second conductive type region is proximal to the second conductive type heavily doped region. 16. The semiconductor device of claim 13, wherein the dummy gate comprises a pair of structures parallel to each other. 17. The semiconductor device of claim 13, wherein the semiconductor device is constructed in a RF test key. 18. The semiconductor device of claim 13, wherein the SOI substrate is a device wafer. 19. The semiconductor device of claim 18, wherein the semiconductor device is formed in scribe lines of the device wafer. 20. The semiconductor device of claim 13, wherein the SOI substrate is a monitor wafer.
044420668	abstract	A supporting floor for the core of a nuclear reactor utilizes a plurality of independent support columns forming the floor of the reactor and resting on the bottom layers of the reactor. The support columns are surrounded by a side reflector which is in turn surrounded by a thermal side shield. Between the thermal side shield and the side reflector are disposed retaining means for maintaining the columns close together and preventing the formation of large gaps during operation.
050770004	claims	1. A method of preparing a reactor coolant pump for vacuum degasification of a reactor coolant system, said preparing method comprising the steps of: (a) sealing a seal housing of the reactor coolant pump by, first, installing a boot support member about a portion of the seal housing and, then, installing a flexible longitudinally split boot member about the portion of the seal housing, over the boot support member, and about a shaft extending through the seal housing such that the boot support member is displosed within and entirely enclosed and covered by the boot member between the boot member and the seal housing with the boot support member internally supporting the boot member; (b) reversing the pressure of the reactor coolant system at start of vacuum degasification of the reactor coolant system, said sealing of the pump seal housing preventing damage to sealing assemblies therein by said reversing of reactor coolant system pressure; (c) terminating reversing of the reactor coolant system pressure at completion of vacuum degasification of the reactor coolant system; and (d) unsealing the pump seal housing of the reactor coolant pump by removing the split boot member. terminating operation of the pump before sealing its seal housing. unsealing the pump seal housing before restarting operation of the pump. 2. The method as recited in claim 1, wherein said installing of said split boot member includes stretching the split boot member. 3. The method as recited in claim 1, further comprising: 4. The method as recited in claim 1, further comprising:
047284889	claims	1. In a water reactor operating environment, the combination having improved fretting wear resistance comprising: an elongated tubular water displacer rod; having a low neutron absorption cross section guide support plates distributed along the length of said water displacer rod; said water displacer rod intersecting said guide support plates through apertures in said guide support plates; said water displacer rod having a plurality of spaced apart annular electrospark deposited coatings, each said coating facing the wall of a respective said aperture, said electrospark deposited coatings comprising Cr.sub.2 C.sub.3 ; wherein said water displacer rod has a tube wall composed of a zirconium base alloy; and wherein said guide support plates are composed of a stainless steel alloy. a second electrospark deposited coating metallurgically bonded to said walls of said apertures. 2. The combination according to claim 1 further comprising: 3. The combination according to claim 1 wherein said coating is about 0.001 to about 0.002 inches thick. 4. The combination according to claim 1 wherein said zirconium base alloy is selected from the group consisting of Zircaloy-2, Zircaloy-4 and zirconium-niobium alloys.
060884274	description	DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT As is shown schematically in FIGS. 1 and 2, an apparatus for radiological examination generally includes a radiation source 10 which is preferably and typically an x-ray generator. Radiation 13 is directed towards the body of a patient 11 lying on an appropriate examination table 12. The radiation 13, after having passed through the body of the patient, reaches an arrangement 14 which includes a holder for a film or plate 15 that is to be impressed with an image. The arrangement 14 further includes a grid that is formed by lead strips 16 separated from each other by elements of an x-ray transparent material. The grid is displaced in a reciprocating motion by an appropriate driving mechanism when the apparatus is operating. The grid 16 performs the task of filtering the x-rays scattered by the irradiated elements, i.e. the patient. Because such scattered rays would affect the quality of the image that is impressed on the photographic film or plate, it is desired to have them filtered. In order to ensure a good radiographic image, the reciprocating motion of the grid must, as far as possible, occur at a constant speed. However, the grid 16, caused to be displaced with a reciprocating motion, can give rise, due to its mass, to vibrations over the entirety of the apparatus. As a result, this can contribute to lowering the quality of the attainable radiographic image. It would also cause a further inconvenience to the patient, who is usually lying quite close to the arrangement 14 that is receiving the image. In order to eliminate such drawbacks, the present invention provides a counterweight for balancing the oscillating mass of the grid 16. According to a further preferred feature of the present invention, a stepper motor is used as the driving means for the grid and the counterweight, crank-connecting rod mechanisms are used as motion transmission mechanisms between the motor and the grid as well as the counterweight, and a power electronic control arrangement is provided for the stepper motor. This will be explained in further detail below. Turning to FIGS. 5 and 6, the arrangement 14 including the holder for holding the film or plate 15 to be impressed with the image and the moving grid 16 is housed in a box-like structure on a side of which the components of the present invention are assembled. The grid 16 is provided with a bracket 17. An end portion of a connecting rod 18 is pivotally connected with the bracket 17, and the other end of the connecting rod is pivotally attached to a crank 19. The crank 19 is also connected to an end portion of a shaft of a stepper motor 20. At the other end of the shaft of the stepper motor 20 is connected a crank 21. A connecting rod 22 is pivotally connected to the crank 21 at one end thereof, and at the other end thereof is pivotally connected to a counterweight 23. The counterweight 23 is adapted to balance the mass of the grid 16 in its reciprocating motion. The cranks 19 and 21 of the respective motion transmission mechanisms from the motor to the grid and the counterweight are, preferably, provided so as to be parallel and out of phase, i.e. out of phase by 180 degrees. With the above structure, accordingly, the counterweight 23 is displaced with a rectilinear reciprocating motion in opposite phase to the grid 16. It should be noted that the counterweight 23 is preferably guided in motion by two shafts 24 and 25 that are connected as end portions thereof to a support 26 of the stepper motor 20 and the chassy of the arrangement 14, respectively. Thus, the counterweight is able to rectilinearly slide on the support shafts 24 and 25. The stepper motor 20 ideally turns at a constant speed. If it turns at a constant speed, the curve of the reciprocating displacement speed of the grid 16, due to the law governing the motion of oscillating masses, will have a sinusoidal profile as illustrated in FIG. 3. With the apparatus according to the present invention, programmable profiles can, on the contrary, be obtained for the reciprocating speed of the grid 16 in view of the elimination of the imbalances that were in the past brought about by inertial forces. For a profile to be obtained which differs from the sinusoidal profile as shown in FIG. 3, the angular speed of the motor needs to be varied on an instant-by-instant basis in accordance with the rotation angle of the crank 19 and the speed profile that is desired to be obtained for the oscillating mass. One such profile is illustrated in FIG. 4. The variation in the angular speed of the motor is obtained by varying the times elapsing between two successive steps of the stepper motor 20. Such times are delivered to the power control unit of the motor by a microprocessor based control arrangement (which is of a per se known type, and, therefore, not illustrated). As a result, the sinusoidal pattern of the reciprocating speed of the grid 16 which is ordinarily brought about by the crank and connecting-rod type of motion transmission mechanism can be compensated for by control of the motor to provide for a constant speed of the grid 16.
	description	This description is the National Stage and claims the priority benefit of international patent application No. PCT/US08/70573, filed Jul. 19, 2008 and entitled “Ex-Vessel Accident Mitigation,” which claims the priority benefit of U.S. Provisional Patent Application Ser. No. 60/963,098, filed Aug. 3, 2007, the disclosures of which are incorporated herein by reference. 1. Technical Field The present invention relates to heat transfer on a large scale, and more particularly to materials that improve heat transfer rates. 2. Description of Related Art Nuclear reactors generally include a vessel in which a nuclear reaction takes place. The vessel generally includes a vessel envelope that encloses a core of nuclear material, control rods, working fluid and the like. Often, the vessel is housed in a large building, described herein as a containment envelope. The containment envelope is generally much larger than the vessel, and is generally sealed or sealable to the outside world up to a maximum pressure, and filled with a gas such as air. Notwithstanding safety measures, uncontrolled nuclear reactions may result in the generation of heat within the vessel beyond the ability of the heat transfer apparatus to remove the heat. In such cases, the core may fail, and temperatures within the vessel may rise to temperatures above 500, 1000, 1500, 2000, 2500, or even 3000 degrees Celsius. In some cases, the vessel and associated apparatus may transfer sufficient heat from a failed core that the vessel envelope remains substantially intact. In other cases, the failed core material may breach the vessel and enter the containment environment. Vessel envelopes may be designed to resist temperatures up to 600, 800, 1000, 1200 or even 1400 degrees Celsius, but core materials may reach temperatures over 2400 degrees Celsius. The mass of various core materials and vessel materials may be very large (e.g., hundreds or even thousands of tons). As such, the trajectory of the ex-vessel core material, (often described as “corium”) from the vessel to a surface of the containment is largely influenced by gravity (e.g., the corium may fall to a “floor” of the containment envelope). Contact between the corium and containment envelope typically degrades the containment envelope and associated components, often due to the high temperature of the corium. The removal of heat from the corium should occur at a faster rate than the generation of heat by the corium. The removal of heat from the corium should also be faster than a degradation of the containment envelope in order to prevent or delay a breach of the containment envelope. Cooling liquids (e.g., water) may contact the corium and remove heat from the corium via evaporation of the liquid. However, evaporation generally increases the total gas pressure inside the containment, and so evaporated liquids (e.g., steam) may generate significant hydrostatic pressure in the containment (e.g., greater than 3, 7, 10, 15, 20, 30, 40, 50, or even 100 atmospheres) which may exceed the maximum pressure that the containment envelope can contain. Increasing the size of the containment envelope may increase the rate of condensation (in that the total mass of condensing fluid generally increases with increasing surface area upon which it is condensing), but increasing the size of the containment envelope too much may cause other problems, such as reduced resistance to internal pressure. For a given containment envelope inner surface area, increasing a condensation rate of a vapor phase (on the inner surface) that has (in evaporating) removed heat from the core material may be desirable. To reduce pressure within the containment envelope, heat absorbed by evaporation may be transferred (e.g., to the outside world) before the pressure inside the containment envelope rises above a critical pressure associated with failure of the containment envelope. Condensation of a gas or vapor may transfer heat from the vapor to a surface. However, many materials that are liquids at room temperature may have condensation rates on an inner surface of the containment envelope that are slower than their associated evaporation rates at the corium. For example, water may condense at approximately 100 degrees, and an inner surface temperature may be 30 degrees, but ex-vessel material (evaporating the water) may be 2900 degrees. A condensation rate may be mismatched with an evaporation rate when the boiling point (or the condensation temperature) is relatively close to the temperature of the inner surface and much lower (e.g., 500, 1000, 1500, 2000, or even 2500 degrees lower) than the first temperature and/or temperature of the ex-vessel core material. When a gaseous boundary layer is formed between hot, ex-vessel core material at a first temperature and a liquid having a boiling point far below the first temperature (e.g., water cooling of 2400 degree core material), heat transfer to the liquid may be relatively reduced by a gaseous boundary layer. In such cases, heat transfer from the core material may not necessarily “benefit” from water's boiling point being hundreds, or even thousands of degrees below the core material temperature. As such, using a cooling liquid with a higher boiling point may result in rates of heat transfer from the core material to the liquid that are at least as fast as heat transfer to water. Thus, the removal of heat from an ex-vessel mass of core material, in a manner that does not lead to containment overpressure and/or failure may reduce the risk of containment breach. Methods and apparatus may increase the safety of nuclear reactors, particularly in an ex-vessel nuclear accident. Certain aspects provide for liquid and/or vapor phase heat transfer away from hot core material (or other heat sources) by using substances having heat transfer rates to a containment envelope that are large enough to prevent overpressure, thermal, and/or chemical degradation of the containment. Certain aspects provide for heat transfer materials having a melting point between an expected ex-vessel core material temperature and an expected inner surface temperature. These materials may be chosen such that a mass transfer rate associated with condensation of the material in cooler regions of the containment envelope is at least as fast as mass transfer rates associated with evaporation of the material in the region associated with the hot core material. Various aspects provide for an inner surface of a substantially sealed containment envelope and systems and methods to transfer heat from ex-vessel core material to a region outside the containment envelope without degradation and/or overpressurization of the containment envelope. In certain aspects, a first material disposed in a position to absorb heat from ex-vessel core material has a melting point below a first temperature associated with an estimated temperature of the ex-vessel core material or a failure temperature of the vessel or another temperature. Generally, the first material may have a boiling point below a second temperature associated with a temperature of an inner surface of the containment envelope, and the first material may be characterized by thermodynamic and kinetic properties such that heat is transferred from the first material to the containment envelope at a fast enough rate (e.g., via condensation) that a vapor phase associated with the first material does not (or is not expected to) become greater than a critical pressure associated with a pressure limit of the containment envelope. In some aspects, the first material may have a boiling point above 100 degrees Celsius at 1 atmosphere of pressure. In other aspects, the first temperature may be above 500 degrees Celsius, and in some cases, the boiling point of the first material is below the first temperature. In certain aspects, the first material may have a melting point between 50 and 800 degrees Celsius. In certain aspects, the first material may have a boiling point at 1 atmosphere between 150 and 2800 degrees Celsius, and in some cases, the first material may have a boiling point between 800 and 2700 degrees Celsius, or even between 900 and 1900 degrees Celsius. In some aspects, the first material may have a melting point between 200 and 700 degrees Celsius, and a boiling point between 800 and 2650 degrees Celsius. In some aspects, the first material may have a melting point greater than a second temperature associated with the inner surface. In some aspects, the first material comprises a composition that is not expected to react exothermically with any component comprising more than 1% of the breached core material, the vessel envelope material, associated materials or any combination thereof. In certain aspects, an inner surface is expected to reach a third temperature, between the first and second temperatures. Generally, the third temperature may be within 400 degrees of the second temperature, and may be associated with a heating of the inner surface during an accident. In certain aspects, the first material has a boiling point above the third temperature, and in some cases, the first material has a melting point below the third temperature. The first material may comprise one or more materials, and in some cases, one or more materials may be characterized by a difference between their respective melting and boiling points of at least 100 degrees Celsius at atmospheric pressure. In some embodiments, the difference between melting and boiling points may be as great as 2700 degrees Celsius. In certain aspects, a liquid phase associated with the first material has a viscosity below 1000 cp, below 100 cp, or even below 10 cp. In some cases, a liquid phase first material may spread out into a shallow “puddle” which increases the surface area of the first material with respect to its volume. The density of a solid and/or liquid phase of the first material may be greater than a density associated with one or more components of the core material, vessel material, and/or associated material. Various apparatus may include a system to substantially contain a liquid phase of first material 160, and these apparatus may generally be operable to temperatures above 800, 1100, or even 1400 degrees Celsius. In certain cases, these apparatus may substantially contain a liquid first material and substantial quantities of ex-vessel core material associated with the first material. In certain cases, the liquid phase of the first material is denser than various core materials, and various apparatus contain the liquid first material and associated core materials with a sufficient depth and volume that the core materials are buoyantly “floated” above a floor of the containment. In some cases, floating may be enhanced via various boundary layers associated with vaporization of the first material. In select embodiments, a first material may comprise any of or a combination of Pb, Zn, Sn, S, Bi, and Al, often as uncombined species. In a preferred embodiment, a first material may be substantially comprised of metallic Pb. In other embodiments, a first material comprises S, which may also provide for desired chemical reactions with the core material. Select embodiments feature various apparatus such as fins, rods, mesh, tubes, channels and other devices, associated with the containment envelope, generally configured to increase a condensation rate of the first material in cooler regions of the containment. Generally, an inner surface area of a containment envelope may be maximized as necessary to increase condensation rates thereon. Substantial amounts of the inner surface of the containment may be in fluid communication with a region associated with the first material, particularly when the first material is removing heat from ex-vessel core material. In some cases, substantial amounts of the inner surface are in “line of sight” fluid communication with the interacting first material. Select aspects feature various heat transfer apparatus associated with the containment envelope, often located “outside” of the inner surface, and typically configured to transfer heat from inside the containment envelope to the outside world without transferring matter from inside the containment envelope to the outside world. In some embodiments, these apparatus feature tubes, fins, and/or other apparatus substantially inside the containment envelope, often incorporating a fluid to transfer heat outside of the containment envelope. Various aspects include a design for any of the apparatus described herein, a method comprising the use of any of the apparatus described herein, and a method comprising the fabrication of any of the apparatus described herein. Certain embodiments feature a method for increasing the public's tolerance of nuclear power comprising the describing of any of the apparatus described herein and a way in which these apparatus may improve safety. Some embodiments may not require the choice or determination of a first or second temperature. Any claimed limitation may be combined with one or more other claimed limitations. Various embodiments may be used to cool reactor vessels, even when the vessel has not been breached. Although various embodiments are described in the context of nuclear reactors, they may also be used to transfer heat from other hot materials to cooler regions of a containment containing the hot materials. Generally, a nuclear reactor may include a building or other structure (herein, a containment envelope) within which a reactor vessel is located. Typically, the containment envelope is sealed or may be sealed to the outside environment such that the substances within the containment envelope cannot escape to the outside environment. The reactor vessel typically houses fissile material (e.g., uranium, oxides of uranium, and/or other materials comprising actinoids), various packaging materials (e.g., zircaloy), control rods, and a working fluid. FIG. 1 is a schematic of a reactor vessel in a containment envelope, incorporating various embodiments. Vessel 100 contains core material 110, and may be located within containment envelope 120. Containment envelope 120 includes an inner surface 130, which may have an inner surface area much larger (e.g., 3 times, 10 times, 100 times, 1000 times, 10,000 times, or even 100,000 times) larger than an outer surface area of vessel 100 (i.e., containment envelope 120 may be much larger than vessel 100). Containment envelope 120 may generally seal the environment within from the outside world. Containment envelope 120 may be characterized by a pressure limit describing a maximum pressure of a gas phase 140 within, beyond which containment envelope 120 may fail (e.g., allow passage of material from within to the outside world). Generally, the pressure of gas phase 140 may result from the vapor pressures of all gaseous phases within the containment envelope. Typical pressure limits may be of the order of a few atmospheres (e.g., 2-8), a few tens of atmospheres, or in some instances a few hundreds of atmospheres. In various implementations, a first material 160 may be disposed within containment envelope 120, such that upon a breach of vessel 100 by core material 110, the breached core material comes into contact with first material 160. The mass of first material 160 may be of the same order as, or even larger than, the mass of the core material 110. In some embodiments, first material 160 may have a mass of several tons, several tens of tons, over 100 tons, over 1000 tons, or even over 10,000 tons. First material 160 may be have a shape designed to maximize the contact area between first material 160 and the ex-vessel core material. In some aspects, first material 160 is located substantially beneath vessel 100. In other aspects, various structural components 170 may be included within the containment that guide the breached (i.e., ex-vessel) core material (which may include vessel material and/or other materials) to first material 160. Structural components 170 may comprise steels, Ni and/or Co-based alloys, ceramics, carbides and the like, and may include materials to control heat transfer, chemistry or other factors in addition to structural properties. Structural components 170 may also increase the surface area to volume ratio of the breached core material. First material 160 may comprise a solid and/or a liquid. Solid forms of a first material 160 may be disposed without associated structures to “retain” them, and in such cases first material 160 may subsequently melt during an accident and substantially spread out after having melted. Solid or liquid first material 160 may also be disposed within a system to contain a liquid phase of first material 160, annotated as pool 165 on FIG. 1. Pool 165 may substantially contain the liquid phase and/or associated core materials disposed within. Pool 165 may be located as desired, for example at, above, or below a “floor level” of containment envelope 120. Pool 165 may also include a top surface that provides for support (e.g., walking on) of first material 160 during normal use, and in some cases this top surface may yield to descending corium during an accident, allowing contact between the corium and first material 160. In some aspects, heat transfer apparatus 150 associated with containment envelope 120 may operate to remove heat from containment envelope 120, typically without an associated mass transfer between the interior of containment envelope 120 and the outside environment. Heat transfer apparatus 150 may include fluids, cooling tubes, pipes, fins, heat pipes and/or other heat transfer systems. Certain aspects may optionally include apparatus to enhance the interaction between containment envelope 120 and gas phase 140, such as wires, tubes, fins, mesh and the like. For example, fins 180 may generally have high surface area, and may have high thermal conductivity and/or be configured to conduct heat from the gas phase 140 to containment envelope 120. Inner surface 130 and/or fins 180 may also include a surface coating designed to increase the adsorption of a vapor phase associated first material 160, to react with first material 160, and/or improve the emissivity associated with this surface. Generally, descriptions of interactions with inner surface 130 may include interactions with fins 180 and the like. A choice of first material 160 may optionally include knowledge or an estimate of a first temperature, typically associated with a temperature from which first material 160 may be transferring heat. A first temperature may be associated with a failure of vessel 100 or an associated material. Vessel 100 may be characterized by a first temperature, which may be associated with an estimated, calculated, or known transition from “in-vessel” failure to “ex-vessel” failure (i.e., breach of the vessel by the core material). Typically, the first temperature may be associated with a thermal, mechanical and/or chemical breakdown of the vessel envelope containing the overheated core material (which is at or above the first temperature). The first temperature may be chosen arbitrarily, although the choice of a first temperature (and matching first material) should generally correspond to the predicted temperature of the material that will ultimately be cooled by first material 160. A first temperature may be estimated for most solids (which would be used to construct vessel 100) and associating the first temperature with a failure temperature of the vessel may be a convenient way to estimate a lower limit of the first temperature. For some vessel envelope materials, the first temperature may be a melting point of the solid from which the vessel is constructed. For other materials, the first temperature may be the temperature at which the yield stress decreases below a critical threshold. For some vessel materials, the first temperature may be associated with a threshold creep rate or a rate at which a chemical reaction reaches a critical speed. The first temperature may also be estimated using melting points associated with molten core materials, or may be an expected temperature of the ex-vessel core material. In certain aspects, a first temperature may be between approximately 500 and 3000 degrees Celsius, and for some aspects, the first temperature may be between 700 and 2000 degrees Celsius. In that the first temperature may generally be associated with failure of the vessel, improved reactor vessels may likely result in increasingly higher first temperatures. The first temperature may also be associated with the temperature of the core material that breaches the vessel, and so could be over 1500, 2000, 2500, 3000, or even 3500 degrees Celsius. In certain aspects, a first temperature is between 2200 and 3200 degrees Celsius. In some aspects, the first temperature may be associated with a driving force for transferring heat from breached core material to first material 160, generally correlated with a difference between the first temperature and the temperature of first material 160, which under typical circumstances may be close to ambient temperature (e.g., 25 degrees Celsius). First material 160 may remove heat from a concentrated source (e.g., the ex-vessel core material) to a diffuse (i.e., large area) inner surface, and so a first material 160 may be chosen that optimizes a “serial” process of heat and/or mass transfer from the core material to first material 160 to the containment envelope, subject to a pressure limit constraint within the containment envelope. This process may include a first step of absorbing heat (e.g., from the breached core material), a second step of transporting the heat away from the heat source, and a third step of releasing heat (e.g., to the containment envelope). First material 160 may be chosen such that its thermodynamic and kinetic properties maximize heat transfer from the ex-vessel core material to first material 160, spread the heat from the core material to a much larger inner surface area of the containment envelope, and transfer the heat to the containment envelope fast enough that the containment envelope does not overpressurize, preferably while not damaging the containment envelope. Such properties may include without limitation: melting point, boiling point, mass, atomic number, gas phase transport kinetics, adsorption kinetics, interactions with surface chemistries and the like. In some aspects, first material 160 may be chosen according to a first temperature and a second temperature, which may be associated with an actual or expected temperature of inner surface 130. The second temperature may also be associated with the “receipt” of heat, from the core material, via first material 160. Inner surface 130 may be characterized by a second temperature, lower than the first temperature, generally below 100 degrees Celsius (particularly before an accident) and often near ambient temperature during normal operation. Inner surface 130 may be cooled (including water cooled or even N2 cooled). First material 160 may generally have a melting point below the first temperature and a boiling point above the second temperature. First material 160 may be a solid or a liquid near room temperature and/or the inner surface temperature. First material 160 may be characterized by a melting point of the solid phase, a boiling point of the liquid phase, and various characteristics describing the solid, liquid or gaseous phases (e.g., viscosity of the liquid, vapor pressure vs. temperature of the vapor phase). Generally, first material 160 may absorb heat (e.g., from the breached core material), via heat capacity and one or more phase transitions. In a preferred embodiment, first material 160 may absorb heat via heating of a solid phase, melting of the solid phase, heating of the liquid phase, and evaporation of the liquid phase. In some cases, first material 160 may be chosen such that a combination of enthalpy of melting, integrated enthalpy of heating to vaporization, and enthalpy of vaporization is maximized between the second and first temperatures. For a solid first material 160 at ambient or operational temperatures, first material 160 may absorb heat by melting. Liquid phase first material 160 may flow, spread, and otherwise convectively transfer heat away from the contacting core material. In certain aspects, spreading of this liquid phase may be used to increase heat transfer to the containment envelope, and in some cases, may increase heat transfer associated with evaporation of this phase. Spreading may also create a wide, shallow “puddle” of liquid first material 160. In some cases, a puddle may be characterized by a depth that is substantially (e.g., 10 times, 100 times, or even 1000 times) smaller than its length and/or width. In some aspects, a puddle may have a higher surface area to volume ratio than the ex-vessel core material being cooled. The region of first material 160 contacting the core material may also be designed to have a depth that provides for a large contact area between the core material and first material 160, and a region far from the core material may be designed to have a shallow depth that increases heat transfer to the containment envelope (e.g., a pool with a deep center and shallow edges). For some combinations of a first temperature and boiling point of first material 160 (e.g., with a breached core material at a temperature above the boiling point of first material 160), first material 160 may also absorb enough heat to change to a vapor phase, and in such cases, vapor transport of the vapor phase may remove heat from the core material. It may be advantageous to choose a first material 160 with a high boiling point. However, the boiling point should generally not be so high that the containment envelope beneath or otherwise contacting the boiling liquid first material 160 is significantly degraded by the hot liquid phase. In some aspects, condensation of first material 160 on inner surface 130 is maximized, and at least as fast as first material 160 evaporates, subject to the constraints of the vapor pressure remaining below the pressure limit and the boiling point being below a temperature associated with degradation of the portion of the containment envelope contacting the liquid first material 160. In certain embodiments, first material 160 is chosen to have a high vapor pressure at the first temperature (subject to heat transfer kinetics from the core material to the liquid phase) to maximize vapor phase transport of mass (and thus heat) from the breached core material, and to maximize condensation on the inner surface 130. The total area of inner surface 130 available for concentration may also be adjusted in this optimization. In certain aspects, the boiling point of first material 160 may be above 800, 1500, 2000, or even 2500 C. In some cases, the melting point of first material 160 may be between 50 and 600 degrees Celsius. In a preferred embodiment, the melting point of first material 160 is between 200 and 600 degrees Celsius. In some embodiments, the boiling point of first material 160 is between 400 and 2700 degrees Celsius. In certain cases, it may be preferable that first material 160 is solid at ambient temperatures (e.g., has a melting point above 25 degrees Celsius). In a preferred embodiment, the design and/or layout of various components maximizes the vapor phase transport from first material 160 to inner surface 130 and heat transfer to inner surface 130 therefrom. Such designs may include maximizing the area of inner surface 130, and optionally maximizing those areas with “line of sight” exposure to first material 160 when first material 160 is evaporating. For some possible accident conditions (e.g., hundreds of tons or more of core material at 2500 degrees Celsius or higher temperatures), apparatus including first material 160 and inner surface 130 may operate as a very large “heat pipe,” transferring heat from the breached core material (contacting the first material) to the inner surface 130, via vapor phase transport of first material 160. Pressure of gas phase 140 within containment envelope 120 may generally increase as increasing amounts of first material 160 evaporate. Pressure may be reduced by condensing first material 160 on inner surface 130, and so this condensation rate may be maximized in preferred implementations. In select embodiments, first material 160 may have a boiling point significantly above the second temperature and/or temperature of inner surface 130 (before and/or during an accident). In some aspects, the boiling point of first material 160 may be above 150, 400, 800, 1200, 1600, 2000, or even 2400 degrees Celsius. In certain aspects, the difference between a melting point and a boiling point of first material 160 may be more than 100, 500, 1400, or even 2300 degrees Celsius. In some aspects, the first temperature may be above 700 degrees Celsius and the second temperature may be below 110 degrees Celsius. In certain aspects, first material 160 has a melting point above 50 degrees Celsius and a boiling point above 600 degrees Celsius. In some aspects, first material 160 may have a boiling point above 110 degrees Celsius at the pressure limit, and in some cases, the boiling point may be above 500, 800, 1100, 1700, 2200, or even 2700 degrees. However, in that the driving force for evaporation may be generally associated with the difference between the first temperature and the boiling point, first material 160 may generally be chosen (in evaporative embodiments) to have a boiling point substantially below the first temperature. In some cases, it may be advantageous to use a first material 160 having a boiling point below 3200, 2650, 2250, 1850, or even 1650 degrees Celsius. In certain embodiments, a rate of mass transfer associated with the condensation of gaseous first material 160 onto inner surface 130 is at least as high as a rate of vapor phase mass transfer from the core material to inner surface 130, which is at least as high as the mass transfer associated with the evaporation of first material 160. In a preferred embodiment, the condensation of first material 160 on inner surface 130 is at least as fast as the evaporation of first material 160 in the region contacting the breached core material, and this evaporation is fast enough to cool the breached core material. In some aspects, heat transfer associated with condensation of first material 160 on inner surface 130 is at least as fast as a rate of heat generation from nuclear and/or chemical reactions involving the breached core material. In some implementations, first material 160 is characterized by a vapor phase having a condensation rate on inner surface 130 sufficiently fast that the vapor pressure of first material 160 within containment envelope 120 does not exceed the pressure limit of containment envelope 120. In a preferred embodiment, first material 160 may be chosen such that the evaporation kinetics (including heat transfer, boundary layer properties, turbulence, contact area and other factors) associated with the ex-vessel core material substantially “match” the condensation kinetics (including adsorption, heat transfer, surface area and the like) on inner surface 130. The condensation of first material 160 on inner surface 130 may be increased by increasing the area of inner surface 130, which may include the use of high surface area apparatus such as (but not limited to) fins 170, wires, pipes, mesh and the like. In some embodiments, it may be advantageous to choose a first material 160 having a boiling point near an average of the first and second temperatures, near an average of the logarithm of the absolute first and second temperatures, or near approximately 30% or 60% of either of these averages. In an exemplary embodiment, a first temperature is between 700 and 2700 degrees Celsius, a second temperature is between 15 and 100 degrees Celsius, first material 160 has a melting point between 50 and 800 degrees Celsius, and first material 160 has a boiling point between 800 and 2800 degrees Celsius. In a preferred embodiment, the boiling point of first material 160 may be substantially below (e.g., more than 400, 800, or even 1300 degrees Celsius below) the first temperature, which may increase the vaporization rate of first material 160, yet above the second temperature, which may increase heat transfer to inner surface 130. In some embodiments, the boiling point of first material 160 may be substantially greater than the second temperature (e.g., more than 100, 200, 400, or even 600 degrees Celsius greater). A boiling point of first material 160 may be above 600, 1000, 1400, or even 1800 degrees. In some embodiments, the melting point of first material 160 may be below an expected temperature of fins 180 or even inner surface 130 during an accident (i.e., between the first and second temperatures), and first material 160 may condense as a liquid on these surfaces. In some of such cases, apparatus such as fins 180 may be configured to guide the condensed liquid first material 160 back to the breached core material and “replenish” the supply of first material 160 available for heat transfer. In select embodiments, it may be advantageous to control the temperature of the fins such that first material 160 condenses as a liquid on these surfaces, yet the temperature is still sufficiently below the boiling point of first material 160 that the driving force for condensation is large. In some cases, it may be advantageous to choose a first material 160 having a density (of a condensed phase) that is greater than an expected density of the breached core material. In a preferred embodiment, such a dense phase of first material 160 may provide for heat transfer away from the breached core material while buoyantly floating the breached core material away from the floor of containment envelope 120. Pb may be a preferred material in such applications. In certain embodiments, first material 160 may comprise a material having a melting point below 700 degrees Celsius. In some embodiments, first material 160 may comprise a material having a boiling point above 900 degrees Celsius. Certain embodiments may include first materials 160 comprising any of Pb, Zn, Sn, Bi, S, and Al. In certain aspects, first material 160 may be substantially comprised of Pb. First material 160 may also be comprised of oxides, particularly mixed oxides having the desired melting and boiling points, including Na2O, K2O. First material 160 may include amorphous materials. Eutectic compositions may be used. Cementitious materials may be used. First material 160 may be a composite material comprising a plurality of substances, which may have different melting points, boiling points, and condensation rates. Core materials, cooling fluids, and even the ambient gas may include reactive species, and in some embodiments it may be advantageous to choose a first material 160 expected to have a minimal reactivity among a set of undesired reactions. Highly electronegative metals such as zirconium alloys may oxidize by reducing the oxides of metals having reduced electronegativities, and so choosing a non-oxide first material 160 may be advantageous in some embodiments. In other circumstances, air, oxygen, oxides, and/or water may be available for reaction, and so choosing a first material 160 that has relatively lesser tendency to oxidize, react with water, and/or reduce different oxides may be advantageous. In that the breached core material may include a plurality of species, it may be advantageous to use a fixed material 160 that is not expected to exothermically react with any component comprising more than 1% of the expected breached core material. Metals such as Pb and Zn may have a relatively modest tendency to react with various oxides, and are not sources of oxygen. Metals such as Al may form protective oxide layers that inhibit exothermic reactions. Components of first material 160 may also be chosen to provide a preferred chemical reaction with one or more species of the core material, including a reaction that modifies the viscosity of a liquid and/or a reaction that immobilizes a substance. Various methods and apparatus disclosed herein may be incorporated with other apparatus and methods as necessary to enable the features described. The above description is illustrative and not restrictive. Many variations of the invention will become apparent to those of skill in the art upon review of this disclosure. The scope of the invention should, therefore, be determined not with reference to the above description, but instead should be determined with reference to the appended claims along with their full scope of equivalents.
050193287	description	DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIG. 1, a natural circulation type boiling light-water reactor according to an embodiment of the present invention has a pressure vessel 1 which is divided into a steam/water chamber and a steam chamber. A reactor core 2 provided with a fuel assembly including a plurality of fuel elements is disposed in the steam/water chamber of the pressure vessel 1. A core shroud 3 encircles the reactor core 2. A tubular chimney 4 extends from an upper end portion of the core shroud 3 towards the steam/water chamber. The chimney 4 is filled with light water as coolant. The inside diameter of the chimney 4 is greater than the outside diameter of the core shroud 3. In addition, an end 41 of the chimney 4, that is, a water surface of the coolant, is opened towards a steam dryer assembly 5 which will be described later, and therebetween there exists nothing to restrict the effective open area of the water surface. The steam dryer assembly 5 is disposed above the chimney 4, through which the steam/water chamber and the steam chamber of the pressure vessel 1 are communicated with each other. The dryer assembly 5 is mounted on a circumferential flange 13 projected radially inwards from the wall of the pressure vessel 1. A tubular steam guide 6 is attached to an outlet of the steam dryer assembly 5. The steam guide 6 is fixed to a top head portion 12 of the pressure vessel 1 through a stay 61. The steam guide 6 extends upwards within the steam chamber. When the top head portion 12 is assembled into the pressure vessel 1, projections 61 provided in the steam guide 6 are abutted onto eyenuts 51 provided in a top end of the dryer assembly 5 to press it against the projection 13 so as to fixedly retain it with respect to the projection 13. A steam outlet 7 is provided in a portion of the wall of the pressure vessel 1 corresponding to the steam chamber. An operation of the reactor having the abovedescribed arrangement will be described hereinunder. First, when the reactor is driven, the reactor core heats and boils the light water so as to generate steam. The steam generated comes up as main steam within the chimney 4. The main steam further comes up from the water surface of the coolant in a gas-liquid two-phase state (that is, steam and water droplets) toward the steam dryer assembly 5. As a result, the light water overflows from the chimney end 41 to flow down through a space defined between the pressure vessel 1 and both the chimney 4 and the shroud 3 towards the bottom of the reactor core, and then, it is heated again by the reactor core. In this way, a natural circulation of the coolant is accomplished. While the main steam passes through the steam dryer assembly 5, the wetness fraction thereof is reduced, and the main steam then comes up within the steam chamber along the steam guide 6 while being guided by the same. Subsequently, the main steam flows down toward the steam outlet 7 so as to be supplied to the turbine system through the steam outlet 7. Thus, a steam path is so formed that it extends from the shroud 3 to the steam outlet 7. In the present embodiment, the end 41 of the chimney 4, that is, the water surface of the coolant, is opened towards the steam dryer assembly 5. In other words, between the water surface of the coolant and the steam dryer assembly 5, there exists nothing to restrict the effective open area thereof. To the contrary, in a conventional forced circulation boiling light-water reactor shown in FIG. 2, a shroud 3 is closed at the end portion thereof, and a steam separator assembly 8 which comprises a plurality of steam separators each having a reduced sectional area is communicated with the closed end portion of the shroud. (Elements acting in the same manner as the corresponding ones shown in FIG. 1 are designated by the same reference numerals, respectively, and description of the operation thereof will be omitted. It is noted, however, that the dimensions of the elements designated by the same reference numeral are substantially equal with each other.) In the reactor shown in FIG. 2, since the effective area of the steam path is decreased by the steam separator assembly 8, the velocity of the main steam flowing within the steam separator assembly 8 is increased. Therefore, it takes the main steam about five seconds to flow from the shroud 3 to the steam outlet 7, that is, through the steam path. On the other hand, in the present embodiment, since no steam separator assembly 8 is provided, the effective area of the steam path is never decreased. In consequence, the main steam comes up slowly from the chimney end 41 at a reduced velocity towards the steam dryer assembly 5, thus flowing through the steam path taking a time period longer than five seconds. In addition, since the inside diameter of the chimney 4 is made greater than the outside diameter of the core shroud 3, the velocity of the main steam flowing within the chimney 4 is reduced less than the velocity of the main steam in the core shroud 3. Further, in the present embodiment, the provision of the steam guide 6 makes it possible to prevent the main steam from taking a short cut from the steam dryer assembly 5 to the steam outlet 7. Namely, the steam path is prolonged. In consequence, the time period while the main steam flows through the steam path is made further longer. By referring to FIGS. 3A and 3B, description will be given of the relationship between the length of the steam path and the velocity of flow of the main steam in detail making a comparison between the reactor of the present embodiment shown in FIG. 1 and the reactor shown in FIG. 2. A velocity V1 of the main steam flowing within the chimney 4 is lower than a velocity v1 of the main steam flowing within an extended part of the core shroud which corresponds to the chimney (V1<v1). This is because, on the assumption that the amounts of the main steam generated in the reactor cores per unit time are identical, the velocity of the main steam flowing through the extended part of the shroud, the effective sectional area of which is equal to the sectional area of the core shroud 3, is unchanged and identical to that flowing through the core shroud 3, while the velocity of the main steam flowing within the chimney 4, the effective sectional area of which is increased as compared with the sectional area of the core shroud 3, is reduced. In addition, a velocity V2 of the main steam flowing through the space defined between the chimney 4 and the steam dryer assembly 5 is lower than a velocity v2 of the main steam flowing within the steam separator assembly 8 which corresponds to the space referred above (V2<v2). This is because the velocity of flow of the main steam flowing within the steam separator assembly 8, the effective sectional area of which is decreased, is increased, while the velocity of the main steam flowing through the open space defined between the chimney 4 and the steam dryer assembly 5 is reduced. In this way, since the main steam flows through substantially the same distance (L1+L2=l1+l2) at a reduced velocity according to the present embodiment, it takes a longer time to flow from the core shroud 3 to the steam dryer assembly 5 in comparison with the conventional one. Subsequently, in the steam dryer assembly 5, the velocity of the main steam is reduced at a predetermined rate in either case (V3<v3 and L3=l3). The main steam coming out of the steam dryer assembly 5 then flows within the steam chamber at a velocity V4 which is smaller than a velocity v4 obtained in the conventional one (V4<v4). Furthermore, in the present embodiment, since the steam guide 6 prevents the main steam from taking a short cut to the steam outlet 7 that is, since the steam path is prolonged (L4>l4), it takes the main steam a longer time period to flow from the steam guide 6 to the steam outlet 7, as compared with the conventional one. As clearly seen from the foregoing description, according to the reactor of the present embodiment, the time period while the main steam flows within the pressure vessel is made longer as compared with the conventional reactor. That time period is about five seconds in the conventional reactor, so that the time period referred above can be made sufficiently longer than a half-life of .sup.16 N (about seven seconds) provided that the dimensions of the elements are unchanged. As a result, the amount of .sup.16 N contained in the main steam can be remarkably reduced within the pressure vessel 1. In consequence, the amount of .sup.16 N in the main steam to be supplied to the turbine system is small so that a shield structure which is reduced in size and weight in comparison with conventional ones can be safely applied to the turbine and the piping systems. Comparison will be made between the reactors shown in FIGS. 1 and 2 in terms of the relationship between the .sup.16 N inventory index (inventory of .sup.16 N in the main steam/inventory of .sup.16 N in the main steam in the conventional core shroud (shown in FIG. 2)) at various spots of the power plants and the time period for the main steam to travel from the core shroud 3 to the respective spots, with reference to FIGS. 4A to 4C. Incidentally, reference numerals 9, 10 and 11 designate a reactor housing vessel, a high pressure turbine, and a low pressure turbine, respectively. As understood from the drawings, in the conventional power plant, the time period to travel to the steam dryer assembly 5 is about one second and that to the steam outlet 7 is about five seconds. On the other hand, according to the present embodiment, the time period to travel to the steam dryer assembly 5 is prolonged to about eight seconds and that to the steam outlet 7 is prolonged to about fourteen seconds (or twice of the half-life of .sup.16 N). This results in that although the inventory of .sup.16 N at the steam outlet 7 in the conventional power plant is 60% of that in the core shroud, the inventory of .sup.16 N at the steam outlet 7 in the power plant employing the present embodiment is reduced to 25% of that in the core shroud. That is to say, the inventory of .sup.16 N at the steam outlet 7 according to the present embodiment is reduced to about 40% (=25/60) in comparison with that according to the conventional art. This means that the thickness of the shield structure for the turbine system can be reduced by about 15 cm upon calculation in terms of concrete. According to the present invention, the above-mentioned effects can be obtained by reducing the velocity of the main steam within the pressure vessel and/or increasing the length of the flow path for the main steam. In consequence, other embodiments than the above-described one are also practicable; the one in which axial dimension of the chimney 4 is increased, the one in which a resistance through a passage of the steam dryer assembly is increased, and the like. Further, the above-described guide 6 is not limited to the illustrated one employed in the present embodiment and it may be replaced by the one which is inclined toward the direction opposite to the steam outlet or the one which spirals.
	summary
050911201	abstract	Process for obtaining nuclear fuel pellets, which produces no liquid effluent, for which the starting product is metallic uranium, which is oxidized to U.sub.3 O .sub.8, then crushed and either reduced to UO.sub.2 and activated (or vice versa) with the aid of at least one fine milling operation, or reduced to UO.sub.2 and activated using at least one oxidation-reduction cycle, the UO.sub.2 obtained then being shaped by pressing and fritting and the intermediate powders obtained are dense and pourable, no intermediate conditioning operation being required.
	claims	1. A guide thimble plug of a nuclear fuel assembly, the guide thimble plug comprising:a main body having an internal threaded hole located through the main body, the main body for coupling to a bottom nozzle in a lower end by the internal threaded hole and directly coupling to a shock absorption tube and a guide thimble in an upper portion thereof;an upper insert part located in an upper end of the main body and having an external thread located on a circumferential outer surface thereof for coupling to the shock absorption tube;a thermal deformation prevention part located on the main body below the upper insert part, the thermal deformation prevention part being recessed inward from an outer surface of the main body, wherein when the main body is coupled to the guide thimble, a gap is defined between the thermal deformation prevention part and the guide thimble; anda protruding part located between the upper insert part and the thermal deformation prevention part and havingan upper surface in the upper insert part side, the upper surface being perpendicular to the outer surface of the main body so as to support a lower end of the shock absorption tube,a lower surface in the thermal deformation prevention part side, andan outer surface on a circumferential outer surface thereof, the outer surface having a diameter greater than a diameter of the thermal deformation prevention part, for being forcibly fitted into the guide thimble,wherein a width of the thermal deformation prevention part is two or more times greater than a width of the protruding part. 2. A guide thimble plug of a nuclear fuel assembly, the guide thimble plug comprising:a main body having an internal threaded hole located through the main body, the main body for coupling to a bottom nozzle in a lower end by the internal threaded hole and directly coupling to a shock absorption tube and a guide thimble in an upper portion thereof;an upper insert part located in an upper end of the main body;a caulking groove located on a circumferential outer surface of the upper insert part in a circumferential direction, the caulking groove for coupling the main body to the shock absorption tube by caulking,a thermal deformation prevention part located on the main body below the upper insert part, the thermal deformation prevention part being recessed inward from an outer surface of the main body, wherein when the main body is coupled to the guide thimble, a gap is defined between the thermal deformation prevention part and the guide thimble;a protruding part located between the upper insert part and the thermal deformation prevention part and havingan upper surface in the upper insert part side, the upper surface being perpendicular to the outer surface of the main body so as to support a lower end of the shock absorption tube,a lower surface in the thermal deformation prevention part side,an outer surface on a circumferential outer surface thereof, the outer surface having a diameter greater than a diameter of the thermal deformation prevention part, for being forcibly fitted into the guide thimble, andwherein a width of the thermal deformation prevention part is two or more times greater than a width of the protruding part. 3. A guide thimble plug of a nuclear fuel assembly, the guide thimble plug comprising:a main body having an internal threaded hole located through the main body, the main body for coupling to a bottom nozzle in a lower end by the internal threaded hole and directly coupling to a shock absorption tube and a guide thimble in an upper portion thereof;an upper insert part located in an upper end of the main body;at least one caulking depression located on a circumferential outer surface of the upper insert part at positions spaced apart from each other in a circumferential direction, the at least one caulking depression for coupling to the shock absorption tube by caulking;a thermal deformation prevention part located on the main body below the upper insert part, the thermal deformation prevention part being recessed inward from an outer surface of the main body, wherein when the main body is coupled to the guide thimble, a gap is defined between the thermal deformation prevention part and the guide thimble; anda protruding part located between the upper insert part and the thermal deformation prevention part, the protruding part havingan upper surface in the upper insert part side, the upper surface being perpendicular to the outer surface of the main body so as to support a lower end of the shock absorption tube,a lower surface in the thermal deformation prevention part side,an outer surface on a circumferential outer surface thereof, the outer surface having a diameter greater than a diameter of the thermal deformation prevention part, for being forcibly fitted into the guide thimble, andat least one caulking depression indicator located on the upper surface of the protruding part, each of the at least one caulking depression indicator adjoining a respectively corresponding caulking depression,wherein a width of the thermal deformation prevention part is two or more times greater than a width of the protruding part.
	abstract	Systems and methods of transferring nuclear fuel from fuel pools having size and/or weight limitations to a storage or transport cask are disclosed. A canister containing spent nuclear fuel is inserted into a transfer cask. A shielding sleeve is then placed around the transfer cask. A lifting device simultaneously lifts the transfer cask and the shielding sleeve over a storage cask and the spent fuel is transferred from the transfer cask to the storage or transport cask.
	summary
051436540	description	DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be explained with reference to FIGS. 1 and 2. In this embodiment, a concentrated radioactive liquid waste, such as a radioactive waste generated from an atomic power plant, is dried into the form of a powder, and then granulated into pellets. The pellets are charged into a container and solidified by a solidifying agent that is poured into the container to cover the pellets. A flowchart of the process of an embodiment of the invention is shown in FIG. 1. FIG. 2 shows a schematic representation of an apparatus for performing the process. In a first step 21, radioactive liquid waste from an atomic power plant, for example, preferably having radioactive nuclide(s) of known type is stored in a tank 1. The liquid waste is transferred from tank 1 to dryer 2, which may be a centrifugal thin-film dryer, for example. In step 21 the liquid waste is concentrated by drying it in dryer 2 to form a powder. It is preferred that the powder is further pelletized in a pelletizer 3 in a step labeled 22 in FIG. 1. Thereafter, the pellets are charged in container 4, as shown in step 23. Alternatively, as shown in step 23 in FIG. 1, the dried powdered waste can be charged in container 4 without the intermediate step of pelletizing. In accordance with the present invention, a solidifying agent is introduced into container 4 for solidifying the pelletized waste. In preparing the solidifying agent, first a concentration ratio o is determined in step 24. The concentration ratio o is determined by estimating what the concentration of the radioactive liquid waste will be with respect to its present state after concentrating the waste by drying it in dryer 2 and converting it into powder or pellet form for charging it in container 4. The distribution coefficient Kd of the solidifying agent is then determined on the basis of the estimated concentration ratio .alpha. in step 25. The solidifying agent with the desired distribution coefficient Kd is prepared in step 26 from one or more of a plurality of solidifying agent components selected according to the type of radioactive substances present in the waste and based upon each solidifying agent component's coefficient of distribution with respect to the type of radioactive substances present in the waste. In FIG. 2, for example, two solidifying agent components are shown as being contained in tanks 6a and 6b, respectively. The mixture of these solidifying agent components is controlled by a controller 5 in accordance with the desired distribution coeffioient Kd. Controller 5 controls the opening and closing of valves 10a and 10b, respectively, to deliver the appropriate proportions of the solidifying agent components from tanks 6a and 6b into solidifying agent tank 7. Then, the solidifying agent 7 is mixed with water from tank 8 in a mixing tank 9. The solidifying agent in tank 9 is then poured into the container 4 in step 27, and thereafter the contents of container 4 are hardened to a solidified body in step 28. After hardening, a final solidified waste is obtained. The final solidified waste contains approximately 8 to 10 times as great an amount of radioactive substances as a conventional cement-solidified waste having the same solidified volume because the conventional cement-solidified waste is produced merely by solidifying a radioactive liquid waste with cement in a container as it is without subjecting the waste to prior volume-reduction processing. Therefore, the container of solidified waste reduced according to the present invention has an 8 to 10 times greater radioactive concentration than that of the conventional cement-solidified waste of the same quantity. Table 2 shows the measured value of the distribution coefficient of each solidifying agent component with respect to the ions of a plurality of radioactive nuclides found in the radioactive waste of an atomic power plant. TABLE 2 __________________________________________________________________________ Measured Value of Distribution Coefficient of Solidifying Agent Components with Respect to Nuclides (Saturated Na.sub.2 SO.sub.4 solution, 25.degree. C.) Solidifying agent ml/g Sodium Calcium.sup.1 Oxine-added Ion Cement silicate Zeolite Bentonite salt charcoal __________________________________________________________________________ Cs 1 90 20 100 50 1 C 70 10 0 0 500 -- Co 930 600 50 20 50 27000 Sr 20 4300 -- 5 50 300 Ni 2000 2000 50 20 50 27000 .alpha. waste 2000 2000 -- 200 -- -- __________________________________________________________________________ .sup.1 calcium hydroxide --: no measured data The measurement of a distribution coefficient is explained with reference to the following example. Assuming that a concentrated radioactive liquid waste is a regenerated liquid waste of a desalting ion exchange resin (the main ingredient thereof being Na.sub.2 SO.sub.4) generated from an atomic power plant, 50 ml of saturated aqueous Na.sub.2 SO.sub.4 solution is charged into the tank. To this solution are added 0.01 .mu.Ci/ml of the ions of one of the six nuclides shown in Table 2 and thereafter 1 g of the articles of one of the solidifying agent components shown in Table 2 obtained by pulverizing the solidified component. After the elapse of time sufficient for reaching the adsorption equilibrium, the solution is separated from the solidifying agent component, and the concentration (.mu.Ci/ml) of the nuclide in the solution and the concentration (.mu.Ci/g) of the nuclide in the solidifying agent component are measured by X-ray measurement. The value obtained by dividing the measured value of the latter concentration by the measured value of the former concentration is the distribution coefficient with respect to the solidifying agent component. The distribution coefficient varies greatly in accordance with different radioactive nuclides and solidifying agent components. In the present invention, the composition of the solidifying agent is adjusted to obtain the desired distribution coefficient according to the concentration of the radioactive nuclide of a solidified radioactive waste having its volume reduced so that the amount of leaching of the solidified waste is equal to or smaller than that of a conventional cement-solidified waste of the same type and quantity. The solidifying agent comprises one or more of the solidifying agent components shown in Table 2. To determine the most effective solidifying agent component or mixture of components in preparing the solidifying agent, the various distribution coefficients shown in Table 2 are noted with respect to the type of radioactive substance contained in the waste to be solidified. An analysis of the considerations involved in preparing the desired solidifying agent is discussed as follows. Any given nuclide of the six nuclides shown in Table 2 is selected as a noticeable nuclide represented by j, and any given solidifying agent component shown in Table 2 is represented by k. The distribution coefficient of k with respect to j is represented by Kd.sub.jk. In the preparation of the solidifying agent, two cases are considered. In the first case, a single solidifying agent component is used for solidifying the radioactive waste. In the second case, a solidifying agent comprising a plurality of mixed solidifying agent components is used to solidify the radioactive waste. (1) The case of using a single solidifying agent component Let the amount of nuclide leached from a solid body be ##EQU1## wherein C.sub.j represents the concentration of the nuclide j in the solid waste. The intended condition is ##EQU2## If the concentration ratio of the radioactive nuclide j powdered or further pelletized from its original state as a liquid waste is .alpha..sub.j, formula (2) is represented as follows: ##EQU3## wherein Kd.sub.j1 represents the distribution coefficient of cement (i.e., represented by k=1). In the case (1) of using a single solidifying agent component, the single solidifying agent used is not ordinarily conventional cement, such as Portland cement and blast furnace cement, namely k.noteq.1. Although the distribution coefficients vary with respect to different solidifying agent components and radioactive nuclides, generally there is almost no nuclide dependence of the concentration ratio .alpha..sub.j obtained by volume reduction. In other words, .alpha..sub.j substantially has the same value with respect to any nuclide j. EXAMPLE 1 In the case of solidifying a dried powder of Cs, which has been concentrated by 10 times by volume reduction, with sodium silicate, the condition of formula (4) holds and is represented as follows when the data of Table 2 is substituted: ##EQU4## Additionally, in the case of using a single solidifying agent component, the amount of Cs or Co leached is not reduced with any solidifying agent component shown in Table 2 as compared with that of a conventional cement-solidified waste. However, it is advantageous to reduce the elution ratio, as shown in Example 1, by paying special attention to C.sub.s, which is a nuclide having a long half life. (2) The case of using a solidifying agent comprising a plurality of mixed solidifying agent components In this case, the general formula corresponding to formula (4) is represented as follows: ##EQU5## wherein Kd.sub.ja, Kd.sub.jb . . . represent the distribution coefficients of the respective solidifying agent components used: a (k=a), b (k=b), . . . ; W.sub.a, W.sub.b, . . . represent the mixing ratios by weights of the respective solidifying agent components; and the following relationship holds: EQU W.sub.a +W.sub.b +. . . =1 (1) EXAMPLE 2 In the case of solidifying a dried powder of Cs, which is concentrated by 10 times by volume reduction, with a solidifying agent obtained by mixing sodium silicate with cement, formula (6) is represented as follows: ##EQU6## wherein k=I means cement and k=b represents sodium silicate. Since Kd.sub.jl =1 and Kd.sub.jb =90 from Table 2, formula (78) is represented as follows: ##EQU7## Since W.sub.1 +W.sub.b =1, if W.sub.1 =0.89 and W.sub.b =0.11, the condition of formula (9) is represented by the following expression, and sufficiently holds: EQU 0.89+90.times.0.11=10.8>10 EXAMPLE 3 In the case of solidifying a dried powder of Co and Cs, which are concentrated by 10 times by volume reduction, with a solidifying agent obtained by mixing sodium silicate and oxine-added charcoal with cement, formula (6) relating to Co and Cs is represented as follows: ##EQU8## wherein k =1 means cement, k =b represents sodium silicate and k =c represents oxine-added charcoal. From the data of Table 2, Kd.sub.jl =1, Kd.sub.jb =90 and Kd.sub.jc =1 with respect to Cs; and Kd.sub.jl =930, Kd.sub.jb =600 and Kd.sub.jc =27000 with respect to Co, and the conditions of the following three formulas hold when the data is substituted: ##EQU9## If W.sub.1 =0.6, W.sub.b =0.1 and W.sub.c =0.3 by solving the conditions of these three formulas, the formulas (11) and (12) hold and it is possible to greatly reduce the amount of Cs and Co leached as compared with that of a conventional cement-solidified waste. In Example 1, the result of formula (5) is 90, which leaves too much margin for the limit 10. When a solidifying agent is expensive, for example, it is more desirable from the point of view of cost to use a satisfactory amount of solidifying agent as in Examples 2 and 3 than to leave too much margin. In order to actually obtain the concentration ratio .alpha..sub.j in carrying out the present invention, a concentrated liquid waste is sampled from a storage tank or the supply tank and the concentration of the solid content (the portion which is to be powdered or pelletized as a result of the drying process) therein is measured, thereby calculating the concentration ratio .alpha. obtained by powdering and pelletization. As described above, there is actually almost no nuclide dependence of the concentration ratio o and, in fact, .alpha..sub.j takes almost the same value with respect to any nuclide j. In a standard concentrated liquid waste (the main ingredient is Na.sub.2 SO.sub.4, 20 wt %), .alpha.=6 to 8 in the case of powdering, and .alpha.=8 to 10 in the case of pelletization. The nuclide concentration C.sub.j is determined by .gamma.-ray measurement or by .beta.-ray measurement at the time of the above-described sampling measurement. A solidifying agent is prepared as a general rule by using the above-described formulas on the basis of the concentration ratio o obtained by measurement of the sampled liquid waste from the storage tank or the supply tank 1 (or from the drier 2) at every solidification process. Actually, however, since the concentration ratio o is substantially determined by the particular volume reduction process and the solidifying system that is used, as described above, it is more practical to use a solidifying agent prepared in advance that corresponds with that system. For example, .alpha. is about 10 in the case of pelletization, so a solidifying agent containing sodium silicate as the main ingredient is prepared in advance. An example thereof is the solidifying agent (called cement glass) prepared by mixing cement and sodium silicate described in Example 2. As the noticeable nuclide j, the six nuclides shown in Table 2 are fundamentally selected, but it may be more convenient or practical to use one of the following three nuclides contained in a liquid waste. ______________________________________ Cs-137 Representative nuclide Same group: generated due to the .alpha. waste, breakage of atomic fuel Sr-90 Co-60 Representative nuclide Same group: generated due to corrosion Ni-63 C-14 Not belonging to the above two groups ______________________________________ More simply, it is possible to select only Cs-137 as the noticeable nuclide which has a long half life (about 30 years) and radiates .gamma. rays, thereby facilitating measurement. Additionally, it is more logical in actual execution of the present invention to take the concentration, the content, the half life, etc. of a nuclide into consideration as well as the concentration ratio .alpha. when selecting the solidifying agent components and the mixing ratio thereof. For example, even if the concentration of Co-60 (half period: 5.8 years) mixed with Cs-137 (half period: 30 years) is about 10 times as high as that of Cs-137, the concentrations of both nuclides are on the same level in about 20 years and thereafter Cs-137 has a higher concentration. Therefore, if the control period (300 years in Japan) of the final disposal facility is taken into consideration, it can be said to be more logical to select a solidifying agent while selecting Cs-137 as the noticeable nuclide. In FIG. 3, a comparison is shown between the amounts of leaching of solidified wastes produced according to the present invention (Comparative Example I), and according to a conventional cement-solidified waste process (Comparative Example II). The amount of radioactive nuclide leached is represented as a value standardized on the basis of the amount of Cs leached in Comparative Example I as "1". The solidified waste in Comparative Example I is an embodiment of the present invention produced by drying a concentrated liquid waste to form powder, pelletizing the powder and solidifying the pellets with sodium silicate as a solidifying agent, while the solidified waste in Comparative Example II is a conventional cement-solidified waste produced by homogeneously solidifying a concentrated liquid waste with cement as the solidifying agent without first subjecting the waste to volume reduction processing. It is clear that according to the embodiment of the present invention, the effect of preventing leaching of the solidified waste is superior to that of the conventional cement-solidified waste. Further in accordance with another embodiment of the invention, the solidifying agent can be prepared so that the amount of leaching for the solidified body is restricted to a permitted value, such as one generally considered acceptable by the industry or set by an ordinance. If a permitted amount of leaching of a radioactive nuclide j is P.sub.j (Ci/year.multidot.ton) and the radioactive concentration of the nuclide is C.sub.j (Ci/ton), and the distribution coefficient of the solidifying agent with respect to the nuclide j is Kd.sub.jk, the condition of the following formula must hold in order that the permitted value is not exceeded. ##EQU10## That is, for keeping the amount of leaching nuclide lower than the permitted amount, the distribution coefficient of the solidifying agent must satisfy the condition of the following formula. ##EQU11## wherein A is a value determined by several factors, including the proportion of the solidifying agent and radioactive waste contained in the container, the density of the solidifying agent, and so forth. Assuming that the amount of leaching nuclide is regulated by the distribution balance between the nuclide and the solidifying agent, the value A is obtained by the following formula: EQU A=1/(r.times..rho.) (16) Wherein r is a proportion of the solidifying agent in the solidified radioactive waste in the container, and .rho. is the density of the solidifying agent. The radioactive concentration Cj in the solidified radioactive waste may be estimated beforehand by the radioactive concentration of the nuclide j in the tank and the concentration ratio .alpha.. In the case of solidifying radioactive waste with a solidifying agent obtained by mixing more than two solidifying agent components together, the solidifying agent may be prepared on a way similar to that practiced when meeting the conditions of formulas (6) and (7). That is, the solidifying agent is prepared by using the following formulas: ##EQU12## Further, in the case of a radioactive waste having a plurality of noticeable nuclides, the solidifying agent may also be prepared in the same way as disclosed in Example 3. Example 4 An example in which the noticeable nuclide is Cs-137 will be explained. The permitted amount of leaching nuclide of Cs-137 is assumed to be 0.3 Ci/year.multidot.to". The radioactive concentration of Cs-137 and the concentration of the solids content in the tank 1 are measured in a conventional manner. The concentration ratio .alpha. is obtained in accordance with the measured concentration of the solids content and in consideration of the particular concentration steps, e.g., the drying and pelletizing steps. Therefore, if the measured radioactive concentration in the tank 1 is 2 Ci/ton and the concentration ratio .alpha. is 5, the radioactive concentration of Cs-137 in the solidified radioactive waste is estimated to be 10 Ci/ton. Next, if the proportion of the solidifying agent in the container is 0.45 and the density of the solidifying agent (e.g., the mixture of cement and sodium silicate) is 1.7 ton/m.sup.3 (the density of the inorganic solidifying agent, e.g., cement or sodium silicate is about 1.5-2.5 ton/m.sup.3) the value of A becomes 1.3 (m.sup.3 /ton.multidot.y) according to formula (14). Therefore, the distribution coefficient of the solidifying agent must be larger than the following value. ##EQU13## The solidifying agent component is selected based upon the distribution coefficients shown in Table 2. If sodium silicate (50 wt%) and cement (50 wt%) are selected and mixed, the distribution coefficient is 46. Therefore, the mixture thus produced satisfies the condition that the amount of leached nuclide be less than the permitted level. Although in the examples of an embodiment of the invention given above, the liquid waste is concentrated by drying and forming the waste into a powder, pelletizing the powder, and solidifying the powder or pellets with a solidifying agent, the method and apparatus of the present invention are not restricted to these examples, but is also applicable to the volume reduction and solidification of a used ion-exchanged resin slurry that is concentrated into a liquid waste sludge. As a result or the present invention, it is possible to increase the amount of radioactive waste that can be charged into a solidified waste container since solid waste having a higher volume reduction ratio than that of conventional cement-solidified waste is contained within the container. As a result, overhead expenses incurred with respect to the waste disposal cost and storage thereof are reduced. While a preferred embodiment has been described with variations, further embodiments, variations and modifications are contemplated within the spirit and scope of the following claims.
054250722	abstract	In a method of treating a surface 12 of an object 10 contaminated with radionuclides 14, a laser source 16 is directed at the surface 12 to apply a local area 18 of intense heat to the surface 12. The laser source 16 is arranged to pass in a raster manner to cause local melting of the surface 12, surface 12 subsequently solidifying and fixing the radionuclides 14 therein. At least one layer of a coating material be applied before or after the application of the intense heat to fix and seal the radionuclides on or in the object.
054224926	claims	1. A device for calibrating a criticality detector for a nuclear fuel manufacturing plant having a radiation source, the device comprising: a radiation protective holder for containing the radiation source, the holder being aligned with the criticality detector along an axis; measuring means connected to the criticality detector and positioned near the holder parallel with the axis; and guide means connected to the holder and movably connected to the measuring means for moving the holder and radiation source along the axis for being detected by the criticality detector and providing a calibration measurement for the measuring means. 2. The device according to claim 1, wherein the measuring means comprises a rod having a plurality of calibrations. 3. The device according to claim 2, wherein the guide means comprises an upper section spaced apart from a lower section, the upper section and the lower section being connected by a pair of spaced apart connecting bars, one connecting bar being connected to the holder. 4. The device according to claim 3, wherein the upper section is aligned in a horizontal plane with the radiation source. 5. The device according to claim 4, wherein the guide means further comprises a thumb screw. 6. The device according to claim 2, wherein the guide means is made of a nylon material.
050323482	summary	TECHNICAL FIELD The invention concerns a stowage rack for nuclear fuel elements comprising a plurality of cells, a fuel element to be stowed being inserted in each cell. These stowage racks are used to store the fuel element in a pool or under dry conditions and/or to transport them in a shielded container, which is dried after loading. STATE OF THE ART Stowage racks for nuclear fuel elements are normally made up of adjacent prismatic cells, usually of square cross-section and of elongated shape with a long axis. The cross-sectional shape of the cells is generally identical with that of the fuel elements to be stowed, and the height of the cells is at least equal to that of the elements. The racks according to the invention are suitable for stowing non-irradiated nuclear fuel elements requiring sub-critical conditions, and the fuel may be based on uranium oxide exclusively or on any combustible oxide mixtures. However, they are particularly adapted to stowing and transporting irradiated fuel elements under dry conditions in a sheathed container. In this application any rack--also known as a stowage rack--must simultaneously fulfil several functions: transfer of the heat generated by the irradiated fuel elements stowed in it, to the wall of the sheathed container in order to dissipate it. The better the thermal conductivity of the rack material and the better the contact between the rack and the wall of the container, the better this function is fulfilled. neutron absorption to guarantee that the rack filled with fuel is in a sub-critical state, either under dry conditions or when immersed in water during storage in a pool or during operations in which sheathed enclosures are loaded and unloaded; these may also be carried out in a pool. This function is fulfilled by using materials containing neutron absorbing elements such as B, Gd, Hf, Dc, In, Li and the like, said materials being used directly in the design of the rack, or by using neutron absorbers inserted in the fuel elements and by good neutron degradation obtained through forming spaces near said neutron absorbing and neutrophage materials. high enough mechanical strength to support the load of combustible elements during transportation and to maintain the geometry of the rack even in the event of impact, thereby maintaining sub-critical conditions and avoiding the risks of the fuel elements and rods deteriorating as a result of heating and/or crushing. These functions are normally fulfilled by making the walls of the cells from materials arranged in a plurality of superposed layers. For example, material of the sandwich type may be used, comprising at least two layers: a layer of an alloy fulfilling the mechanical strength and heat transfer functions, with preferably homologated properties, and a layer of an alloy or composite material containing a neutron absorber; here the mechanical and thermal properties are not generally homologated. The layers are combined by an known means, e.g. by rolling them together or by electroplating, mechanical assembly, welding etc. The material containing the neutron absorber may, for example, be stainless steel containing approximately 1% of boron or an aluminium alloy containing approximately 3% or boron. Alternatively it may be a fritted boron carbide/aluminium product which may or may not be coated with aluminium, or cadmium, deposited electrolytically on a metal carrier. When an aluminium alloy is used, it is generally supplied in the form of strips which are then attached to the other layers as indicated above. The strips may be obtained by rolling or extrusion from bars of adequate size. The bars must be very homogeneous and very sound (no blistering, cracks etc.), and the larger the bars are the more precautions have to be taken. In spite of the precautions taken, the guaranteed minimum boron content of the flat product is often one point below that of the starting product. The common, cheap form of these materials is the wire supplied in coil form. These are obtained by continuous casting e.g. of a ring a few centimeters in diameter, which is then rolled and/or drawn. Boron aluminium wire with a diameter of approximately 10 mm is manufactured in this way, and its guaranteed boron content is generally 2.5 or 3.5%. Other cell wall designs have been described, also fulfilling the neutron absorbing function. For example, U.S. Pat. No. 4,034,227 (Soot) describes wall members which may be assembled with special tenons to form a rack. The members are pieces which are specially extruded in the cell length direction. They have a complicated cross-sectional shape with a series of projecting notches zig-zagging from one side of a flat wall to the other, parallel with the extruding direction. The notches are open along a generatrix and designed to receive neutrophage rods. Although a design of this type, using neutron absorbing rods, avoids the tricky processing of the kind of material described above, it nevertheless involves extruding pieces with a large cross-section and a complicated profile. This greatly restricts the number of potential suppliers, given the size of the presses which would have to be used and the resultant extrusion problems. An assembly of this type also has the drawback of having a multiplicity of mortise and tenon type joints (36, 38, 39 . . . ) in the corners of the cells; these make it difficult to obtain good mechanical strength and adequate thermal conductivity. OBJECT OF THE INVENTION The object of the invention is a stowage rack for irradiated or non-irradiated fuel elements, which may be used for dry storage or for transporting the elements dry in a sheathed container. The rack must fulfil mechanical strength, heat transfer and neutron absorbing functions. The invention aims to simplify the processing of the materials used in making the racks and consequently to reduce their cost; at the same time the mechanical, thermal and neutron performance of the racks must be easily homologated. Its purpose is therefore to use materials and semi-finished products which are readily available on the market and have known properties. It must be possible to use them directly as they are, without any intermediate metallurgical transformation and without requiring more than simple assembly means. Since these materials and semi-finished products are preferably standardized, they are generally more reliable and less expensive than extruded, rolled or composite items which have been specially researched and developed. Another object of the invention is to have a rack in which at least the mechanical strength and heat transfer functions are separated from the neutron absorbing function, with a further possibility of separating all three functions, thus making it easier to calculate and homologate the performance of the rack. A further object of the invention is to have a rack in which the neutron barrier may optionally be continuous or, preferably, discontinuous.
	claims	1. A method for identifying the unit causing a raw water leak in a condenser of a thermal power plant consisting of n units,wherein n is an integer comprised between 2 and 15,wherein each of the n units is equipped with a cartridge intended to contain an ion-exchange resin in a volume comprised between 50 and 150 mL,comprising the following steps:a) for each of the n units, purifying the ion-exchange resin to be placed in the cartridge;b) for each of the n units, placing the purified ion-exchange resin obtained from step a) in the cartridge;c) for each of the n units, passing a volume of condensate comprised between 500 and 1500 L, into the cartridge containing the purified ion-exchange resin put in place in step b);d) for each of the n units, collecting the ion-exchange resin obtained at the end of step c);e) for each of the n units, regenerating the ion-exchange resin collected in step d) by elution with an aqueous regeneration solution;f) for each of the n units, collecting the eluate obtained at the end of step e) followed by determining the nature of the ionic species present in the eluate and the amount of each ionic species present in said eluate; andg) for each of the ionic species identified in step f), comparing the amounts of the ionic species determined in each of the n eluates. 2. The method for identifying the unit causing a raw water leak in a condenser of a thermal power plant according to claim 1, wherein the ion-exchange resin has a total exchange capacity greater than 1.0 eq/L. 3. The method for identifying the unit causing a raw water leak in a condenser of a thermal power plant according to claim 1, wherein the raw water contains Na+ and/or Ca2+ ions, and the ion-exchange resin is a cationic resin. 4. The method for identifying the unit causing a raw water leak in a condenser of a thermal power plant according to claim 3, wherein step a) is carried out by elution of the cationic resin with a volume of acidic solution at least 2 times the volume of resin. 5. The method for identifying the unit causing a raw water leak in a condenser of a thermal power plant according to claim 4, wherein the acidic solution is a strong acidic solution which has a concentration of Na+ and Ca2+ ions of less than 1 ppb. 6. The method for identifying the unit causing a raw water leak in a condenser of a thermal power plant according to claim 3, wherein step e) is carried out by elution of the cationic resin with a volume of aqueous regeneration solution at least 2 times the volume of resin. 7. The method for identifying the unit causing a raw water leak in a condenser of a thermal power plant according to claim 6, wherein the aqueous regeneration solution is a strong acidic solution which has a concentration of Na+ and Ca2+ ions of less than 1 ppb. 8. The method for identifying the unit causing a raw water leak in a condenser of a thermal power plant according to claim 1, wherein the raw water contains Cl− ions, and the ion-exchange resin is an anionic resin. 9. The method for identifying the unit causing a raw water leak in a condenser of a thermal power plant according to claim 1, wherein n is an integer comprised between 3 and 8. 10. The method for identifying the unit causing a raw water leak in a condenser of a thermal power plant according to claim 1, wherein the cartridge is intended to contain an ion-exchange resin in a volume comprised between 80 and 120 mL. 11. The method for identifying the unit causing a raw water leak in a condenser of a thermal power plant according to claim 1, wherein in step c), the passed volume of condensate is comprised between 800 and 1 200 L. 12. The method for identifying the unit causing a raw water leak in a condenser of a thermal power plant according to claim 1, wherein the ion-exchange resin has a total exchange capacity greater than 1.5 eq/L. 13. The method for identifying the unit causing a raw water leak in a condenser of a thermal power plant according to claim 3, wherein step a) is carried out by elution of the cationic resin with a volume of acidic solution at least 4 times the volume of resin. 14. The method for identifying the unit causing a raw water leak in a condenser of a thermal power plant according to claim 3, wherein step a) is carried out by elution of the cationic resin with a volume of acidic solution at least 5 times the volume of resin. 15. The method for identifying the unit causing a raw water leak in a condenser of a thermal power plant according to claim 4, wherein the acidic solution is a strong acidic solution which has a concentration of Na+ and Ca2+ ions of less than 0.5 ppb. 16. The method for identifying the unit causing a raw water leak in a condenser of a thermal power plant according to claim 4, wherein the acidic solution is a strong acidic solution which has a concentration of Na+ and Ca2+ ions of less than 0.2 ppb. 17. The method for identifying the unit causing a raw water leak in a condenser of a thermal power plant according to claim 3, wherein step e) is carried out by elution of the cationic resin with a volume of aqueous regeneration solution at least 4 times the volume of resin. 18. The method for identifying the unit causing a raw water leak in a condenser of a thermal power plant according to claim 3, wherein step e) is carried out by elution of the cationic resin with a volume of aqueous regeneration solution at least 5 times the volume of resin. 19. The method for identifying the unit causing a raw water leak in a condenser of a thermal power plant according to claim 6, wherein the aqueous regeneration solution is a strong acidic solution which has a concentration of Na+ and Ca2+ ions of less than 0.5 ppb. 20. The method for identifying the unit causing a raw water leak in a condenser of a thermal power plant according to claim 6, wherein the aqueous regeneration solution is a strong acidic solution which has a concentration of Na+ and Ca2+ ions of less than 0.2 ppb.
	summary
039873030	claims	1. A device for detecting a component gas in a sample gas comprising: a housing; source means mounted within the housing for providing radiation in a preselected spectral band having at least one absorption line of the component gas to be detected; detector means mounted in the housing for detecting radiation in the preselected spectral band; a plurality of reference cells, each reference cell containing a reference gas including a standard amount of said component gas to be detected; a sample cell for containing a quantity of sample gas including the component gas to be detected; and sequencer means in the housing for introducing in time sequence each of the reference cells and also the sample cell into an optical path between the source means and the detector means; said detector means being responsive to radiation incident thereon when each of the reference cells is in the optical path and when the sample cell is in the optical path, for producing thereby a plurality of detector output signals whose amplitudes are dependent on the amount of the component gas which may be present in the plurality of reference cells and the sample cell respectively said plurality of signals being operable in predetermined formulation to provide an indication of the concentration of the component gas in the sample gas. the plurality of reference cells comprises a first reference cell for containing a first reference gas including a first standard amount of said component gas to be detected, and a second reference cell for containing a second reference gas including a second standard amount of the component gas to be detected; and said detector means is responsive to radiation incident thereon when each of the three cells is in the optical path, for producing thereby three detector output signals whose amplitudes are dependent on the amount of the component gas which may be present in the first reference cell, the second reference cell, and the sample cell respectively, said three signals being operable in predetermined formulation to provide an indication of the concentration of the component gas in the sample gas. the housing has a cavity for circulating therein a volume of the sample gas; and the sample cell comprises a cell in open communication with the cavity for containing a quantity of sample gas which is a portion of the volume of sample gas circulating within the cavity. a plurality of permanent magnets embedded in the rotating wheel; and a plurality of electromagnets included within the housing for activation in a predetermined sequence to attract and repel the permanent magnets embedded in the wheel, thereby inducing rotation of the wheel. a plurality of timing marks spaced around the periphery of the rotating wheel; and electro-optical means for reflecting optical signals from the timing marks to generate electrical signals for controlling the speed of the rotating wheel. temperature sensing means for detecting the temperature of the gas in the sample cell; and temperature control means responsive to the temperature sensing means for maintaining the temperature of the gas in the sample cell at a desired temperature. a housing; source means mounted with the housing for providing radiation in a preselected spectral band having at least one absorption line of the component gas to be detected; detector means mounted in the housing for detecting radiation in the preselected spectral band; a plurality of reference cells, each reference cell containing a reference gas including a standard amount of said component gas to be detected; a sample cell for containing a quantity of sample gas including the component gas to be detected; sequencer means in the housing for sequentially introducing the reference cells and the sample cell into an optical path between the source means and the detector means; and a screening member mounted in a recessed chamber in communication with the sample cell for maintaining a stable geometry of an interface between the recessed chamber and a region of the skin surface of the body when the device is brought into intimate contact with said region; said detector means being responsive to radiation incident thereon when each of the reference cells and the sample cell is in the optical path, for producing thereby a plurality of detector output signals whose amplitudes are dependent on the amount of the component gas which may be present in the plurality of reference cells and the sample cell respectively, said plurality of signals being operable in predetermined formulation to provide an indication of the concentration of the component gas in the sample gas. a membrane stretched across the recessed chamber for allowing gases from the human body to enter the cavity in the housing while preventing the passage of body fluids thereinto. an adhesive on a portion of the housing in contact with the skin to provide a sealed region between the sample cell and the body. the sequencer means comprises a wheel operable for introducing in time sequence each of the reference cells and also the sample cell into the optical path between the source means and the detector means; and the detector means is responsive to radiation incident thereon when each of the reference cells is in the optical path and when the sample cell is in the optical path for producing thereby a plurality of detector output signals whose amplitudes are dependent on the amount of the component gas which may be present in the plurality of reference cells and the sample cell respectively, said plurality of signals being operable in predetermined formulation to provide an indication of the concentration of the component gas in the sample gas. the housing has a cavity for circulating therein a volume of the sample gas; and the sample cell comprises a cell in open communication with the cavity for containing a quantity of sample gas which is a portion of the volume of sample gas circulating within the cavity. a plurality of permanent magnets embedded in the rotating wheel; and a plurality of electromagnets included within the housing for activation in a predetermined sequence to attract and repel the permanent magnets embedded in the wheel, thereby inducing rotation of the wheel. a plurality of timing marks spaced around the periphery of the rotating wheel; and electro-optical means for reflecting optical signals from the timing marks to generate electrical signals for controlling the speed of the rotating wheel. temperature sensing means for detecting the temperature of the gas in the sample cell; and temperature control means responsive to the temperature sensing means for maintaining the temperature of the gas in the sample cell at a desired temperature. the sequencer means comprises a rotating wheel operable for introducing in time sequence said plurality of reference cells into said optical path; the sample cell is positioned adjacent said wheel for operation in series with each reference cell in the optical path between the source and the detector; and the detector means is responsive to radiation incident thereon when each of the reference cells is in series with the sample cell in the optical path for producing thereby a plurality of detector output signals whose amplitudes are dependent on the amount of the component gas which may be present in the plurality of reference cells and the sample cell respectively, said plurality of signals being operable in predetermined formulation to provide an indication of the concentration of the component gas in the sample gas. a membrane stretched across the recessed chamber for allowing gases from the human body to enter the cavity in the housing while presenting the passage of body fluids thereinto. an adhesive on a portion of the housing in contact with the skin to provide a sealed region between the sample cell and the body. a plurality of permanent magnets embedded in the rotating wheel; and a plurality of electromagnets included within the housing for activation in a predetermined sequence to attract and repel the permanent magnets embedded in the wheel, thereby inducing rotation of the wheel. a plurality of timing marks spaced around the periphery of the rotating wheel; and electro-optical means for reflecting optical signals from the timing marks to generate electrical signals for controlling the speed of the rotating wheel. temperature sensing means for detecting the temperature of the gas in the sample cell; and temperature control means responsive to the temperature sensing means for maintaining the temperature of the gas in the sample cell at a desired temperature. 2. A device as in claim 1 wherein: 3. A device as in claim 2 wherein: 4. A device as in claim 3 wherein the sequencer means comprises a rotating wheel in which the first and second reference cells and the sample cell are positioned. 5. A device as in claim 4 further comprising: 6. A device as in claim 5 further comprising: 7. A device as in claim 6 further comprising: 8. A device for use in measuring the concentration of a component gas in the fluids of a human body, said device comprising: 9. A device as in claim 8 further comprising: 10. A device as in claim 8 further comprising: 11. A device as in claim 8 for use in measuring the concentration of said component gas in the fluids of a human body, wherein: 12. A device as in claim 11 wherein: 13. A device as in claim 12 further comprising: 14. A device as in claim 13 further comprising: 15. A device as in claim 14 further comprising: 16. A device as in claim 8 for use in measuring the concentration of said component gas in the fluids of the human body, wherein: 17. A device as in claim 16 further comprising: 18. A device as in claim 17 further comprising: 19. A device as in claim 16 further comprising: 20. A device as in claim 17 further comprising: 21. A device as in claim 18 further comprising:
	summary
	claims	1. A water jet peening (WJP) method for a nuclear reactor vessel comprising:disposing a clamping cylinder at the outer peripheral side of an instrumentation nozzle with a predetermined gap therebetween;fixing a positioning member provided in the clamping cylinder to the instrumentation nozzle at a position adjacent to the upper end of the instrumentation nozzle;moving an inner surface WJP nozzle downward to the instrumentation nozzle through the clamping cylinder;jetting high-pressure water to an inner surface of the instrumentation nozzle by moving the inner surface WJP nozzle downward in a rotation state while the high-pressure water including cavitation air bubbles is jetted from the inner surface WJP nozzle; anddischarging the high-pressure water jetted from the inner surface WJP nozzle to an outside of the instrumentation nozzle through a drainage hole provided in the positioning member. 2. The water jet peening method according to claim 1,wherein the high-pressure water is jetted from the inner surface WJP nozzle while a thimble tube drawn to an outside of the reactor vessel from the instrumentation nozzle through a conduit tube is not movable. 3. The water jet peening method according to claim 2,wherein a fixed state of the thimble tube and the conduit tube is monitored when the high-pressure water is jetted from the inner surface WJP nozzle to the inner surface of the instrumentation nozzle.
	description	The present application claims priority to U.S. Application Ser. No. 62/325,198, filed Apr. 20, 2016, which is incorporated herein by reference in its entirety Subterranean oil recovery operations may involve the injection of an aqueous solution into the oil formation to help move the oil through the formation and to maintain the pressure in the reservoir as fluids are being removed. The injected water, either surface water (lake or river) or seawater (for operations offshore) generally contains soluble salts such as sulfates and carbonates. These salts may be incompatible with the ions already contained in the oil-containing reservoir. The reservoir fluids may contain high concentrations of certain ions that are encountered at much lower levels in normal surface water, such as strontium, barium, zinc and calcium. Partially soluble inorganic salts, such as barium sulfate (or barite) and calcium carbonate, often precipitate from the production water as conditions affecting solubility, such as temperature and pressure, change within the producing well bores and topsides. This is especially prevalent when incompatible waters are encountered such as formation water, seawater, or produced water. Some mineral scales have the potential to contain naturally occurring radioactive material (NORM). The primary radionuclides contaminating oilfield equipment include Radium-226 (226Ra) and Radium-228 (228Ra), which are formed from the radioactive decay of Uranium-238 (238U) and Thorium-232 (232Th). While 238U and 232Th are found in many underground formations, they are not very soluble in the reservoir fluid. However, the daughter products, 226Ra and 228Ra, are soluble and can migrate as ions into the reservoir fluids to eventually contact the injected water. While these radionuclides do not precipitate directly, they are generally co-precipitated in barium sulfate scale, causing the scale to be mildly radioactive. Because barium and strontium sulfates are often co-precipitated with radium sulfate to make the scale mildly radioactive, handling difficulties are also encountered in any attempts to remove the scale from the equipment. Unlike common calcium salts, which have inverse solubility, barium sulfate solubility, as well as strontium sulfate solubility, is lowest at low temperatures, and this is particularly problematic in processing in which the temperature of the fluids decreases. Modern extraction techniques often result in drops in the temperature of the produced fluids (water, oil and gas mixtures/emulsions) (as low as by 5 C) and fluids being contained in production tubing for long periods of time (24 hrs or longer), leading to increased levels of scale formation. Because barium sulfate and strontium sulfate form very hard, very insoluble scales that are difficult to prevent, dissolution of sulfate scales is difficult (conventionally requiring high pH, long contact times, heat and circulation). This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter. In one aspect, embodiments disclosed herein relate to a method of decontaminating naturally occurring radioactive material (NORM) from downhole equipment that includes injecting a NORM dissolver into an isolated region of a wellbore in which NORM-contaminated production equipment is located; and removing the NORM contaminants from the production equipment. In another aspect, embodiments disclosed herein relate to a method of decontaminating naturally occurring radioactive material (NORM) from downhole equipment that includes isolating NORM-contaminated production equipment from other regions of a wellbore; flushing diesel through the isolated region; injecting a wetting agent into the isolated region to render the NORM-contaminated production equipment water wet; injecting a NORM dissolver into the isolated region; and removing the NORM contaminants from the production equipment. Other aspects and advantages of the claimed subject matter will be apparent from the following description and the appended claims. In one aspect, embodiments disclosed herein relate to the in situ treatment of downhole equipment contaminated with NORM. Specifically, embodiments of the present disclosure relate to methods of treating downhole production equipment having NORM-containing scale thereon without retrieval of the equipment to the surface. Conventionally, mineral scale (not containing NORM) may be treated in place, but occasionally, this scale contaminated tubing and equipment is simply removed and replaced with new equipment. However, when the old equipment is contaminated with NORM, the equipment is conventionally removed from the well and replaced, and the equipment is treated (a costly and hazardous affair) to remove the NORM scale therefrom. At present, a considerable amount of oilfield tubular goods and other equipment awaiting decontamination is sitting in storage facilities. Some equipment, once cleaned, can be reused, while other equipment must be disposed of as scrap. Once removed from the equipment, several options for the disposal of NORM exist, including canister disposal during well abandonment, deep well injection, landfill disposal, and salt cavern injection. Conventional equipment decontamination processes have included both chemical and mechanical efforts, such as milling, high pressure water jetting, sand blasting, cryogenic immersion, and chemical chelants and solvents, all of which occur on topside, not downhole. Water jetting using pressures in excess of 140 MPa (with and without abrasives) has been the predominant technique used for NORM removal. However, use of high pressure water jetting generally requires that each pipe or piece of equipment be treated individually with significant levels of manual intervention, which is both time consuming and expensive, but sometimes also fails to thoroughly treat the contaminated area. When scale includes NORM, this technique also poses increased exposure risks to workers and the environment. In contrast, embodiments of the present disclosure involve chemical treatment of the NORM-contaminated equipment downhole without retrieving the equipment to the surface to await a backlog of equipment needing NORM decontamination. However, in other embodiments, the equipment may be retrieved to the surface after the NORM decontamination occurs, in case, for example, the equipment needs to be repaired or replaced for reasons other than the NORM contamination. Though, by treating the equipment in situ prior to retrieving it to the surface, repair or disposal can commence immediately, rather than first waiting for NORM decontamination to occur. Referring initially to FIG. 1, a production apparatus 100 in accordance with one or more embodiments of the present disclosure is shown. Production apparatus 100 is deployed to a wellbore lined with casing 102 upon the end of a string of production tubing 104 extending from a surface station (not shown). Production tubing 104 terminates at its distal end into a Y-shaped union commonly known as a Y-tool 106. Below Y-tool 106 and in fluid communication with production tubing 104 are a pump string 108 and a bypass string 110. Furthermore, while a Y-tool 106 is shown, it should be understood by one of ordinary skill in the art that any style fluid union can be used to connect production tubing 104 with bypass string 110 and pump string 108. Pump string 108 extends further into casing 102 and includes a pump assembly 112. Pump assembly 112 may be configured to pump wellbore fluids from upper region 114 of casing 102, up through production tubing 104, and to a surface station above the well. Pump assembly 112 may be constructed as an electric submersible pump that includes an inlet 116 and an outlet 118 in communication with pump string 108. A check valve 119 ensures that fluids (e.g. NORM dissolving chemicals) from production tubing 104 and bypass string 110 will not flow into pump assembly 112 unless desired. Optionally, a sensor package 120 mounted to pump assembly 112 records and reports downhole conditions to a pump controller (not shown) or a surface station. Furthermore, a control and power line 122 extends from pump assembly 112, alongside production tubing 104 to a surface control station. Those having ordinary skill will appreciate that control and power line 122 may vary in construction depending on the pump assembly 112. For example, if pump assembly 112 is pressure driven, control and power line 122 may comprise one or more fluid conduits in communication with a surface pressure source and pump assembly 112. Bypass string 110 may run alongside pump string 108 inside casing 102 and extend deeper into a production zone 124. Bypass string 110 may include a bypass section 126, an upper fluid gate 128, a packer assembly 130, and a lower fluid gate 132. Upper and lower fluid gates 128, 132 are devices designed to selectively allow and disallow fluids from outside bypass string 110 to communicate with a bore 136 of bypass string 110. Fluid gates 128 and 132 may be constructed as sliding sleeve type devices, but any remotely operable fluid gate devices can be used. Packer 130 may be expanded after production apparatus 100 is delivered to cased wellbore and acts to hydraulically seal off the annulus between bypass string 110 and cased wellbore and divide that annulus into upper 114 and lower regions 138. A plug 140 capable of being set into and retrieved from bypass tubing 110 selectively allows or blocks off direct communication between bypass tubing 110 and production tubing 104. Plug 140 can either be a physical device deployed and retrieved through production tubing 104 from the surface or can be an electrically or hydraulically operable shutoff valve. Furthermore, if plug 140 is a remotely operable valve, it may be configured to allow large diameter items to pass therethrough when open. For example, a remotely operable flapper valve can be used for plug 140. With both upper and lower fluid gates 128, 132 open, fluid communication between upper and lower regions 114 and 138 is permitted. With upper fluid gate 128 open and lower fluid gate 132 closed, only upper region 114 is in communication with production tubing 104 and pump assembly 112. With upper fluid gate 128 closed and lower fluid gate 132 open, only lower region 138 is in communication with production tubing 104. By selectively manipulating upper fluid gate 128, lower fluid gate 132, and plug 140, numerous operations can be performed on cased wellbore and production zone 124, pump assembly 112, or other production string components without detrimentally effecting other components. During production, pump assembly 112 pumps production fluids from lower zone 138 adjacent to production zone 124 to a surface location through production tubing 104. To retrieve or produce fluids which have flowed into lower zone 138 below packer 130, upper and lower fluid gates 128, 132 are opened and plug 140 is again re-set in bypass string 110. Pump assembly 112 is then activated and fluids from upper zone 114 are drawn into pump assembly 112 through inlet 116 and pumped up through pump string 108, Y-tool 106, and production tubing 104 to a surface destination. As fluids are removed from upper zone 114 by pump assembly 112, they are replenished by formation fluids entering lower zone 138 through perforations 146. These fluids travel through lower fluid gate 132, across packer 130, and out upper fluid gate 128 to upper zone 114. Because plug 140 prevents bypass string 110 from directly communicating with production tubing 104, pump assembly 112 is able to displace fluids from lower zone 138 to surface location through production tubing 104. Absent plug 140, pump assembly 112 would only circulate fluids between bypass string 110 and upper zone 114. Further, in one or more embodiments, a work conduit (not shown) extends from within production tubing 104, through Y-tool 106, through bypass string 110, past upper fluid gate 128, through packer 130, and through lower fluid gate 132. Work conduit may be a wireline assembly, capillary tubing, slickline, fiber-optic line, or coiled tubing, etc. Work conduit can be deployed either to take measurements or to perform work operations. Such work operations can include the injection of treatment chemicals, the manipulation of downhole equipment (e.g. valves), and the cleansing of bores of the production apparatus 100. Such measurements can include temperature, pressure, density, and resistivity of downhole fluids. In one or more embodiments, the system of FIG. 1 may be used to perform NORM decontamination of one or more components of the production apparatus 100 while emplaced in the wellbore. Specifically, bypass string 110 may be used to deliver one or more NORM dissolvers downhole (such as through work conduit). Depending on the component of the production apparatus needing decontamination, the NORM dissolver may be delivered to the appropriate location within the well, while closing off, for example, the producing zone 124 and/or other sections or components of the production apparatus 100. For example, in the event that one or more components of the pump assembly is to be decontaminated, the upper fluid gate 128 may be opened and lower fluid gate 132 may be closed, so that only upper region 114 is in communication with production tubing 104 and pump assembly 112. NORM dissolvers may be applied, and depending on the chemistry of the dissolvers involved a pre-flush with diesel followed by a wetting agent may be first circulated into the upper region 114 to render the contaminants water wet prior to circulation of the NORM dissolver into the upper region 114 and through the pump assembly 112. A production logging tool containing a gamma densitometer may be run before and after the treatment with the NORM dissolver to verify removal of NORM. Prior to re-commencing production, the pump assembly 112 and upper region may be optionally re-flushed with a fluid such as diesel or water. Such fluid containing the dissolved scale may be produced or may be flushed into the formation. Further, while the Y-tool and bypass equipment described in FIG. 1 may readily allow for the isolation of the producing zone 124 from the pump assembly 112, the present disclosure is not limited to the use of the particular production apparatus 100 shown in FIG. 1. Rather, it is envisioned that in any wellbore, the producing zone (and potentially lower completion equipment) may be shut off by a through-tubing plug and cement or a polymeric gel or plug, allowing for treatment of one or more parts of the upper completion. Referring to FIG. 2, an embodiment of downhole production equipment that may be treated in accordance with the present disclosure is shown. In this embodiment, a wellbore 28 extends through a geological formation 30. As illustrated, wellbore 28 is lined with a wellbore casing 38 having perforations 40 through which fluid flows between producing zone 34 and wellbore 28. A string of production tubing 20 extends from a surface station (not shown) and terminates at its distal end at a Y-tool 22. Below Y-tool 22 and in fluid communication with production tubing 20 are a pump string 34 and a bypass string 36. An electric submersible pumping system 26 is suspended below pump string 34. For example, a hydrocarbon-based fluid may flow from formation 30 through perforations 40 and into wellbore 28 adjacent electric submersible pumping system 26. Upon fluids entering wellbore 28, pumping system 26 is able to produce the fluid upwardly through pump string 34, Y-tool 22, and production tubing 20 to wellhead (not shown) and on to a desired collection point. Although electric submersible pumping system 26 may comprise a wide variety of components, the example in FIG. 2 is illustrated as having a submersible pump 32, a pump intake 44, and an electric motor 46 that powers submersible pump 32. Motor 46 receives electrical power via a power cable 48 and is protected from deleterious wellbore fluid by a motor protector 50. In addition, pumping system 26 may comprise other components including a sensor unit 54. One or more of these components of the electric submersible pump 26 may be treated in situ to perform NORM decontamination therefrom, such as by shutting off the producing zone 30 (by packer, plug, and/or cement) from the pumping system 26, and then circulating a NORM dissolver in the section of the wellbore containing NORM-contaminated equipment. Further, while an electric submersible pump is illustrated, it is envisioned that other artificial lift components including other pumps or gas lifts may be treated accordingly as well. In addition to a pump assembly, other production equipment that may be treated in accordance with methods of the present disclosure include, but are not limited to, subsurface safety valves, packers, injection mandrels, gas lifts, monitoring equipment, cables, etc. For example, referring to FIG. 3, another schematic of production equipment is shown. As shown, production equipment 300 may include a subsurface safety valve 305 installed in the upper wellbore to provide emergency closure of the producing conduits in the event of an emergency. There is no limitation on the type of valve that may be used, but in one embodiment, it may be a flapper type valve. Also included in production equipment 300 are one or more chemical injection mandrels 310 connected to chemical injection line(s) for injecting one or more chemicals into the wellbore, and one or more packers 315 for isolating various regions of the wellbore from one another. Further, the location of the components on the production string 320 is not limited, and it is envisioned, for example, that the subsurface safety valve 305 may be above the injection mandrel, etc. Depending on the component needing NORM decontamination and its location, additional isolations may be emplaced in the well to protect the producing zone and/or other equipment. NORM dissolvers may be injected through the injection mandrel or through other means into the well, depending on the location of the component to be decontaminated. Referring now to FIG. 4, FIG. 4 depicts a gas lift system 410 that includes a production tubing 414 that extends into a wellbore. For purposes of gas injection, the system 410 includes a gas compressor 412 that is located at the surface of the well for purposes of introducing pressurized gas into an annulus 415 of the well. To control the communication of gas between the annulus 415 and a central passageway 417 of the production tubing 414, the system 410 may include several gas lift mandrels 416. Each one of these gas lift mandrels 416 includes an associated gas lift valve 418 that responds to the annulus pressure. More specifically, when the annulus pressure at the gas lift valve 418 exceeds a predefined threshold, the gas lift valve 418 opens to allow communication between the annulus 415 and the central passageway 417. For an annulus pressure below this threshold, the gas lift valve 416 closes and thus, prevents communication between the annulus 415 and the central passageway 417. Mineral scale that may be effectively removed from oilfield equipment in embodiments disclosed herein includes oilfield scales, such as, for example, salts of alkaline earth metals or other divalent metals, including sulfates of barium, strontium, radium, and calcium, carbonates of calcium, magnesium, and iron, metal sulfides, iron oxide, and magnesium hydroxide. That is, the scale may include NORM, and may also include other mineral scale precipitated therewith. The NORM may also include radioactive plating that has occurred on the production equipment from non-farrous radioactive metals such as Lead 210 and Pollonium 210. In one or more embodiments, NORM dissolver may include a chelating agent. The chelating agent that may be used in the solution to dissolve the metal scale may be a polydentate chelator so that multiple bonds with the metal ions may be formed in complexing with the metal. Polydentate chelators suitable for use in embodiments disclosed herein include, for example, ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), nitrilotriacetic acid (NTA), ethyleneglycoltetraacetic acid (EGTA), 1,2-bis(o-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid (BAPTA), cyclohexanediaminetetraacetic acid (CDTA), triethylenetetraaminehexaacetic acid (TTHA), salts thereof, and mixtures thereof. However, this list is not intended to have any limitation on the chelating agents suitable for use in the embodiments disclosed herein. One of ordinary skill in the art would recognize that selection of the chelating agent may depend on the metal scale to be dissolved. In particular, the selection of the chelating agent may be related to the specificity of the chelating agent to the particular scaling cation, the log K value, the optimum pH for sequestering and the commercial availability of the chelating agent. In a particular embodiment, the chelating agent used to dissolve metal scale is EDTA, and/or DTPA, or salts thereof. Salts of EDTA and DTPA may include, for example, alkali metal salts and depending on the pH of the dissolving solution different salts or the acid may be present in the solution. In one or more embodiments, the NORM dissolver may be a metal nitrate (the metal having a lower electronegativity than the contaminants). In a particular embodiment, the NORM dissolver may be zirconium nitrate, which may optionally be used in conjunction with an oxidizing agent such as H2O2. Further, as mentioned, the NORM dissolver may be preceded by circulation of diesel and/or a wetting agent to render the tool surfaces (and NORM scale) water wet. Further, following the NORM dissolver treatment, a fluid (such as diesel or water) may be flushed through the region to remove the NORM dissolver. The dissolved NORM may be removed from the wellbore either by production or by flushing the material back into the formation (such as by opening the isolation). Following treatment, a gamma tool may be used to verify that the NORM material has been dissolved and removed from the tool on which it had precipitated. This logging may be compared to a log conducted prior to NORM treatment. Further, after treatment, production of hydrocarbons may resume, though, in some embodiments, it is envisioned that a tool could be replaced (even the tool having been decontaminated) if the tool is not operational for other reasons. However, the downhole treatment of the tool will present fewer risks to the operator and avoid a backlog of equipment topside needing NORM decontamination. Although only a few example embodiments have been described in detail above, those skilled in the art will readily appreciate that many modifications are possible in the example embodiments without materially departing from this invention. Accordingly, all such modifications are intended to be included within the scope of this disclosure as defined in the following claims. In the claims, means-plus-function clauses are intended to cover the structures described herein as performing the recited function and not only structural equivalents, but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures. It is the express intention of the applicant not to invoke 35 U.S.C. § 112, paragraph 6 for any limitations of any of the claims herein, except for those in which the claim expressly uses the words ‘means for’ together with an associated function.
	summary
062556630	summary	INCORPORATION BY REFERENCE This application is based on Japanese Patent Application No. 11-35526, filed Feb. 15, 1999 and Japanese Patent Application No.11-100894, filed Apr. 8, 1999 and its contents are incorporated herein by reference. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charged particle beam exposure apparatus for exposing a sensitive substrate such as a wafer etc. with an image of a pattern formed on a mask or reticle using a charged particle beam. 2. Related Art Conventional exposure methods for charged particle beam exposure apparatus can be classified into the following three types. (1) Spot beam exposure methods (2) Variable-shaped beam exposure methods (3) Block exposure methods These methods of exposure provide excellent resolution when compared to conventional batch transfer methods employing light, but this was provided at the expense of throughput. In particular, with the exposure methods of (1) and (2), throughput is limited because exposure is carried out so as to trace a pattern with a spot of an extremely small spot diameter or with a rectangular beam. Further, the block exposure method of (3) has been developed in order to improve the throughput. Here, a standardized pattern is made into a mask and throughput is improved by batch-projecting this pattern. However, since in this method the number of patterns that can be made into masks is limited, it is necessary to use the variable-shaped beam exposure method together with the block exposure method of (3). Throughput is therefore not improved to the anticipated extent. In order to improve the poor throughput of conventional charged particle beam exposure apparatus, divided projection exposure apparatus in which a substrate is projected and exposed with an image of a pattern formed in a portion of reticle are being developed. With this divided projection exposure apparatus, a plurality of chips are formed on a sensitive substrate (usually a wafer). Regions of each chip are partitioned into a plurality of stripes, and each stripe is divided into a plurality of sub-fields. On the other hand, patterns to be transferred to the chips of the sensitive substrate are formed at the reticles and these patterns are similarly divided into stripes and sub-fields corresponding to the stripes and sub-fields of the chips. An exposure method employing an electron beam will be explained. A reticle stage mounted with a reticle and a wafer stage mounted with a wafer are moved at a fixed speed in accordance with the rate of reduction for pattern projection. At this time, an optical axis of the exposure apparatus passes through each center of stripes of the reticle and the chip. A sub-field on the reticle is irradiated with the electron beam and a pattern formed on the reticle is projected onto the sensitive substrate by an optical projection system so that the sensitive substrate is exposed with an image of the pattern. The electron beam is then deflected in a direction substantially at right angles to the direction of progression of the reticle stage, and the pattern of the mask sub-fields arranged in a line are sequentially projected upon the sensitive substrate so that the sensitive substrate is exposed with the pattern image. When projection exposure of the line of mask sub-fields is complete, projection exposure of the next line of mask sub-fields begins. The direction of deflection of the electron beam is reversed for each line and the patterns of mask sub-fields are sequentially projected in order that throughput is increases. By carrying out exposure using this method, compared to conventional charged particle beam exposure apparatus, each of mask sub-field regions is collectively irradiated with the electron beam so that the sensitive substrate is exposed with an image of the pattern in each mask sub-field. And all patterns with which a sensitive substrate is exposed are formed on the reticle so that throughput can be increased substantially as a result. Optical projection systems for exposure apparatus employing electron beams consist of lenses and deflectors, etc. However, magnetic fields other than the deflecting field by the deflectors are also generated at the same time due to the setting of the semi-angles of the deflecting coils and the setting of the current flowing in each deflecting coil. If magnetic field distribution is expressed with a cylindrical coordinate system (z, r, .theta.) taking the angle of rotation about the optical axis as .theta., the deflection field can be expressed in a form combining components proportional to the lowest order trigonometric functions cos [.theta.], sin [.theta.]. However, the magnetic field for other than the deflection field is expressed by combining components proportional to odd-numbered order trigonometric functions of cos [3.theta.], sin [3.theta.] and cos [5.theta.], and sin [5.theta.], etc. These high-order components do not contribute to electron beam deflection but do cause a group of aberrations referred to as a so-called "four-fold aberrations". These four-fold aberrations cause the image of the electron beam to blur and cause the shape of the projected image to become distorted. This causes undesirable disconnection in an integrated circuit formed on the wafer surface or changes in shape. These four-fold aberrations also occur for deflectors designed so that the 3.theta. component and 5.theta. component of the magnetic field become substantially zero. Conventionally, it has been considered that errors in assembly of the deflectors causes magnetic fields of the 3.theta. component and the 5.theta. component. Therefore, attempts have been made to improve the precision with which the coils are made and the deflectors are assembled. However, such efforts have not brought sufficient results. This kind of problem does not just occur for exposure apparatus employing electron beams, but also occurs when other charged particle beams are employed. SUMMARY OF THE INVENTION It is therefore the object of the present invention to provide a charged particle beam exposure apparatus where the four-fold aberrations generated by the deflectors are reduced. It is a further object of the present invention to provide a highly integrated semiconductor device with a very small line width and a semiconductor device manufacturing method capable of manufacturing this kind of semiconductor device. In order to achieve the aforementioned objects, with a charged particle beam exposure apparatus according to the present invention, semi-angles and ratio of ampere-turn values of deflecting coils of at least one of the deflectors are set in such a manner that a 3.theta. component, 5.theta. component and 7.theta. component of a magnetic field generated by the deflectors become substantially zero. The four-fold aberrations caused by the 3.theta. component, 5.theta. component and 7.theta. component of the magnetic field can therefore be made substantially zero. The deflector comprises n(n.gtoreq.2) sets of deflecting coils with a semi-angle .theta.i of substantially 180.degree..times.i/(2n+1) (i=1.about.n). The ratio of ampere-turn value Ji of each deflecting coil i is then set in such a manner that the following equations (1) and (2) are substantially fulfilled with respect to each integer k from 1 to m. Here, the value of m is set to an arbitrary integer between a minimum value 3 (except that 1 when n=2 and 2 when n=3) and a maximum value (n-1). The deflector may comprise n(n.gtoreq.3) sets of deflecting coils with a semi-angle .theta.i of substantially 180.degree..times.(i-1/2)/(2n-1) (i=1.about.n). The ratio of ampere-turn value Ji of each deflecting coil i is then set in such a manner that the following equations (1) and (2) are substantially fulfilled with respect to each integer k from 1 to m. Here, the value of m is set to an arbitrary integer between a minimum value 3 (except that 2 when n=3) and a maximum value (n-1). ##EQU1## Following constitution may be acceptable for the present invention. The semi-angle and ampere-turn values of the deflecting coils are set in such a manner that the 3.theta. component, 5.theta. component and 7.theta. components of the magnetic field are not generated. In addition to this, the deflecting coils includes a deflecting coil of a semi-angle of 45.degree. or includes two different deflecting coils with a semi-angle sum of 90.degree.. As a result, at least one of the coils of the X-axis direction deflector and the Y-axis direction deflector located at the same position in the optical axis direction are set so as to overlap. In this case, the number of coils can then be reduced by making the coils at the overlapping position a single coil. And a number of current generating devices can be reduced and costs can therefore be reduced by having the sum of the current required for the X-axis direction deflector and the current required for the Y-axis direction deflector flow in this coil. In addition to the above, the deflector comprises n(n.gtoreq.3) sets of deflecting coils with a semi-angle .theta.i of substantially 180.degree..times.i/(2n) (i=1.about.n). The ratio of ampere-turn value Ji of each deflecting coil i can then be set in such a manner that the following equations (1) and (2) are substantially fulfilled with respect to each integer k from 1 to m. Here, the value of m is set to an arbitrary integer between a minimum value 3 (except that 2 when n=3) and a maximum value (n-1). Further, the deflector comprises n(n.gtoreq.3) sets of deflecting coils with a semi-angle .theta.i of substantially 180.degree..times.(i-1/2)/(2n) (i=1.about.n). The ratio of ampere-turn value Ji of each deflecting coil i is then set in such a manner that the following equations (1) and (2) are substantially fulfilled with respect to each integer k from 1 to m. Here, the value of m is set to an arbitrary integer between a minimum value 3(except that 2 when n=3) and a maximum value (n-1). ##EQU2## The deflectors may also comprise n(n.gtoreq.3) sets of deflecting coils, with the semi-angle and ampere-turn values of these deflecting coils being set in such a manner that the 3.theta. component, 5.theta. component and 7.theta. component of the magnetic field substantially do not occur. In this case, a coil supply device can be shared and costs reduced because the ampere-turn values of each of the coils are set to be equal. A highly integrated semiconductor device with an extremely small line width can therefore be made by employing the aforementioned charged particle beam exposure apparatus in a lithographic step in a semiconductor device manufacturing method having a lithographic step.
053735404	claims	1. A spent nuclear fuel shipping basket, comprising: a. a shell having a lower wall section having a greater thickness than the remainder of said shell; b. a plurality of cruciforms extending the length of said shell to receive fuel cans, said cruciforms being formed from a neutron absorber and heat transfer material; and c. a plurality of ring supports spaced apart along the length of said shell such that said ring supports transfer any operating loads to said shell. a. a shell, said shell having a lower wall section having a greater thickness than the remainder of said shell and a plurality of notches spaced apart around its inner circumference and extending the length of said shell; b. a plurality of cruciforms extending the length of said shell to receive fuel cans, said cruciforms being formed from a neutron absorber and heat transfer material; and c. a plurality of ring supports spaced apart along the length of said shell such that said ring supports transfer any operating loads to said shell. 2. The shipping basket of claim 1, wherein said shell is provided with a plurality of notches spaced apart around its inner circumference and extending the length of said shell. 3. The shipping basket of claim 1, wherein said shell is provided with an end plate at one end having a plurality of drain holes. 4. The shipping basket of claim 1, wherein said cruciforms are formed from borated aluminum alloy. 5. A spent nuclear fuel shipping basket, comprising: 6. The shipping basket of claim 5, wherein said shell is provided with an end plate at one end having a plurality of drain holes. 7. The shipping basket of claim 5, wherein said cruciforms are formed from borated aluminum alloy.
	abstract	The invention is related a novel structure for Ga-68 radionuclide generator. It allows two washing solutions to pass through two Ge-68 absorbents to wash out different chemical forms of Ga-68 nuclide. The invention comprises the first method that will withdraw hydrochloric acid solution from the washing bottle and pass it through inorganic resin absorbing column to produce the radioisotope solution of Ga-68 gallium chloride, and the second method that will allow the radioisotope solution of Ga-68 gallium citrate to pass the organic resin absorbing column and then the silica-gel cartridge, and be washed by the hydrochloric acid solution to obtain the radioisotope solution of Ga-68 gallium chloride.
052992420	claims	1. In a nuclear reactor having a core operating in the fast neutron energy spectrum where criticality control is achieved by neutron leakage, a reactor control system comprising: a) dual annular, rotatable reflector rings, the rings including an inner reflector ring and an outer reflector ring, the reflectors concentrically assembled, surrounding the reactor core, and each reflector ring including a plurality of openings, the openings in each ring capable of alignment with each other; b) means for independent driving of each of the annular reflector rings such that reactor criticality can be initiated and controlled by rotation of either reflector ring such that the extent of alignment of the openings in each ring controls the reflection of neutrons from the core. 2. The reactor control system of claim 1 wherein the openings in each reflector ring are of a size to ensure that when the openings in each reflector are not aligned, the reactor is operational due to the reflection of neutrons back to the reactor core where the neutrons initiate and sustain the fission process, and when the openings in each reflector are aligned, the reactor is shutdown due to insufficient reflection of neutrons to the reactor core to allow the reactor to attain criticality. 3. The reflector ring of claim 2 wherein the means for independent driving of each reflector ring includes inner reflector drive means and outer reflector drive means. 4. The reflector ring of claim 3 wherein the inner reflector drive means and the outer reflector drive means each include a reflector drive shaft operably connected to a pinion and ring gear structurally connected to the inner or outer reflector, such that rotation of either drive shaft causes the pinion to turn its respective ring gear to thereby rotate the associated reflector to control neutron leakage from the reactor core.
	description	The instant application claims priority from U.S. Provisional Patent Application Ser. Nos. 62/691,178 filed Jun. 28, 2018 and 62/596,311 filed Dec. 8, 2017, the disclosures of which are incorporated herein by reference. The disclosed and claimed concept relates generally to nuclear power equipment and, more particularly, to a detection apparatus usable with a fuel rod and an instrumentation tube of a fuel assembly of a nuclear reactor. In many state-of-the-art nuclear reactor systems, in-core sensors are employed for directly measuring the radioactivity within the core at a number of axial elevations. Thermocouple sensors are also located at various points around the core at an elevation where the coolant exits the core to provide a direct measure of coolant outlet temperature at various radial locations. These sensors are used to directly measure the radial and axial distribution of power inside the reactor core. This power distribution measurement information is used to determine whether the reactor is operating within nuclear power distribution limits. The typical in-core sensor used to perform this function is a self-powered detector that produces an electric current that is proportional to the amount of fission occurring around it. This type of sensor is generally disposed within an instrument thimble within various fuel assemblies around the core, does not require an outside source of electrical power to produce the current, is commonly referred to as a self-powered detector, and is more fully described in U.S. Pat. No. 5,745,538, issued Apr. 28, 1998, and assigned to the Assignee of this invention. Another type of sensor capable of measuring various parameters of the core, and which is typically disposed within the instrument thimbles in various fuel assemblies around the core, is described in U.S. patent application Ser. No. 15/417,504, filed Jan. 27, 2017. This type of sensor employs a transmitter device that includes a self-powered neutron detector structured to detect neutron flux, a capacitor electrically connected in parallel with the neutron detector, a gas discharge tube having an input end and an output end, and an antenna electrically connected to the output end in series with a resonant circuit. The input end of the gas discharge tube is electrically connected to the capacitor. The antenna is structured to emit a signal comprising a series of pulses representative of the intensity of the neutron flux monitored by the self-powered detector. Other core parameters can also be monitored by their effects on altering the values of the inductance and capacitance of the resonant circuit. Still another in-core sensor, one which does not require signal leads to communicate its output out of the reactor, is disclosed in U.S. Pat. No. 4,943,683, which describes an anomaly diagnosis system for a nuclear reactor core having an anomaly detecting unit incorporated into a fuel assembly of the nuclear reactor core, and a transmitter-receiver provided outside the reactor vessel. The transmitter-receiver transmits a signal wirelessly to the anomaly detecting unit and receives an echo signal generated by the anomaly detecting unit wirelessly. When the anomaly detecting unit detects an anomaly in the nuclear reactor core, such as an anomalous temperature rise in the fuel assembly, the mode of the echo signal deviates from a reference signal. Then the transmitter-receiver detects the deviation of the echo signal from the reference signal and gives an anomaly detection signal to a plant protection system. The sensor actually monitors coolant temperature around the fuel assembly in which it is mounted. While each of the foregoing sensors directly monitors conditions within the core of a nuclear reactor, such sensor have not been without limitation. Improvements thus would be desirable. None of the aforementioned sensors directly monitors conditions within a nuclear fuel rod in the core during reactor operation. Before advanced fuel cladding materials can be put into commercial use they have to be rigorously tested to receive regulatory approval. The existing methodology for testing advanced fuel cladding materials requires fuel rods to be tested over several fuel cycles and examined at the end of the irradiation test. This is a lengthy process that takes several years during which time fuel cladding data is not available. In the existing method, critical data is only obtained during the post irradiation examination activities. What is desired is an in-pile sensor that can be placed within a fuel rod, endure the hazardous conditions over several fuel cycles, and does not require penetrations into the cladding of the fuel rod. This invention achieves the foregoing objective by providing a nuclear fuel rod real-time passive integral detection apparatus with a remote inductive or magnetic interrogator (also known as pulse induction). The detection apparatus includes a resonant electrical circuit configured to be supported within an interior of a nuclear fuel rod and structured to generate a generally sinusoidal response pulse in response to an incoming excitation pulse and transmit the response pulse in the form of a magnetic wave that travels through a cladding of the nuclear fuel rod to another location within a reactor in which the nuclear fuel rod is housed, wherein a characteristic of the generated pulse is indicative of a condition of the fuel rod. The detection apparatus also includes a transmitter structured to be positioned outside the cladding, in the reactor, in the vicinity of the fuel rod and configured to generate the excitation pulse and transmit the excitation pulse through the cladding to the resonant electrical circuit, and a receiver structured to be supported within the reactor outside of the cladding, in the vicinity of the nuclear fuel rod, and configured to receive the response pulse and, in response to the response pulse, communicates a signal to an electronic processing apparatus outside of the reactor. Preferably, the resonant circuit is supported within a plenum of the nuclear fuel rod. In one such embodiment the characteristic of the response pulse is indicative of the center-line fuel pellet temperature. In another such embodiment the characteristic of the response pulse is indicative of fuel pellet elongation. In still another such embodiment the characteristic of the response pulse is indicative of fuel rod internal pressure. Furthermore, the characteristic of the response pulse may be configured to be simultaneously indicative of a plurality of conditions of the fuel rod. An additional resonant electrical circuit can also be located in a bottom portion of the fuel rod in order to provide measurements at two different axial locations. Preferably, the resonant circuit comprises a plurality of circuit components whose properties such as capacitance and inductance are selected to create a response pulse having a unique frequency, which can be interpreted to identify the particular nuclear fuel rod from which the generated pulse emanated. In addition, the detection apparatus may include a calibration circuit that is configured to be supported within the interior of the nuclear fuel rod and structured to generate a static calibration signal when interrogated by the excitation pulse from the transmitter, which can be received by the receiver and used to correct the response pulse received by the receiver for any signal change associated with component degradation or temperature drift. Accordingly, an aspect of the disclosed and claimed concept is to provide an improved detection apparatus usable with a fuel rod from among a plurality of fuel rods of a fuel assembly, the fuel rod having a cladding that has an interior region, the fuel rod being situated within a nuclear reactor, the detection apparatus being cooperable with an electronic processing apparatus situated outside of the reactor. The detection apparatus can be generally stated as including a transmitter that is structured to be positioned outside the cladding and inside the nuclear reactor in the vicinity of the fuel rod and structured to generate an excitation pulse and to transmit the excitation pulse through the cladding and into the interior region, an electrical circuit apparatus having a resonant electrical circuit that is structured to be supported within the interior region and to generate a response pulse in response to the excitation pulse and to transmit the response pulse in the form of a magnetic wave that is structured to travel from the interior region and through the cladding, a characteristic of the response pulse being indicative of a condition of the fuel rod, and a receiver structured to be supported within the nuclear reactor outside the cladding and in the vicinity of the fuel rod, the receiver being structured to receive the response pulse and to communicate to the electronic processing apparatus an output responsive to the response pulse. Another aspect of the disclosed and claimed concept is to provide an improved method of detecting a condition of a fuel rod from among a plurality of fuel rods of a fuel assembly, the fuel rod having a cladding that has an interior region, the fuel rod being situated within a nuclear reactor, the detection apparatus being cooperable with an electronic processing apparatus situated outside of the reactor. The method can be generally stated as including employing a detection apparatus to detect the condition, the detection apparatus having a transmitter that is positioned outside the cladding and inside the nuclear reactor in the vicinity of the fuel rod, an electrical circuit apparatus having a resonant electrical circuit that is supported within the interior region, and a receiver that is supported within the nuclear reactor outside the cladding and in the vicinity of the fuel rod. The employing can be generally stated as including generating with the transmitter an excitation pulse and transmitting the excitation pulse through the cladding and into the interior region, generating with the electrical circuit apparatus a response pulse in response to the excitation pulse and transmitting the response pulse in the form of a magnetic field signal from the interior region and through the cladding, generating the response pulse to have a characteristic that is indicative of the condition of the fuel rod, and receiving the response pulse on the receiver and communicating to the electronic processing apparatus an output responsive to the response pulse. Similar numerals refer to similar parts throughout the specification. An improved detection apparatus 4 in accordance with the disclosed and claimed concept is depicted generally in FIG. 1. The detection apparatus 4 is usable with a fuel rod 6 and an instrument thimble 8, such as are included in a fuel assembly 10 (FIG. 2) of a nuclear reactor that is depicted schematically in FIG. 2 at the numeral 12, which signifies a containment of the nuclear reactor 12. The detection apparatus 4 is situated within the containment of the nuclear reactor 12, and the detection apparatus 4 is cooperable with an electronic processing apparatus 16 that is situated external to the containment of the nuclear reactor 12. The detection apparatus 4 is thus intended to be situated within the harsh environment situated within the interior of the containment of the nuclear reactor 12 whereas the electronic processing apparatus 16 is situated in a mild environment external to the containment of the nuclear reactor 12. As can be understood from FIG. 1, the electronic processing apparatus 16 can be seen as including a transceiver 18 and a signal processor 22. The transceiver 18 is connected with a wired connection with an interrogation apparatus 48 that is situated in the instrument thimble 8. The signal processor 22 includes a processor and storage 24, with the storage 24 having stored therein a number of routines 28, and the storage 24 further having stored therein a number of data tables 30. The routines 28 are executable on the processor to cause the detection apparatus 4 to perform various operations, including receiving signals from the transceiver 18 and accessing the data tables 30 in order to retrieve values that correspond with aspect of the signals from the transceiver 18 that are representative of conditions inside the fuel rod 6. As can further be understood from FIG. 1, the fuel rod 6 can be said to include a cladding 32 and to have an interior region 36 situated within the cladding 32 and a number of fuel pellets 38 situated within the interior region 36. As employed herein, the expression “a number of” and variations thereof shall refer broadly to any non-zero quantity, including a quantity of one. The fuel rod has a plenum 42 in generally a vertically upper end of the fuel rod 6. The detection apparatus 4 can be said to include an electrical circuit apparatus 44 that is supported within the plenum 42 of the fuel rod 6 within the interior region 36 thereof. The detection apparatus 4 further includes the interrogation apparatus 48, which can be said to be situated within an interior of the instrument thimble 8. As is schematically depicted in FIG. 1, the electrical circuit apparatus 44 is situated within the interior region 36 and communicates with the interrogation apparatus 48 without any breaches or other openings being formed in the cladding 32, thereby advantageously keeping the cladding 32 intact and advantageously keeping the fuel pellets 38 fully contained within the interior region 36. As can be further understood from FIG. 1, and as will be set forth in greater detail below, the electrical circuit apparatus 44 and the interrogation apparatus 48 communicate wirelessly with one another. Conditions within the interior region 36 of the fuel rod 6 can be said to include a temperature of the fuel pellets 38, an extent of physical elongation of the fuel pellets 38, and the ambient pressure within the interior of the fuel rod 6, by way of example. These three conditions are directly detectable by the electrical circuit apparatus 44 and are communicated through the interrogation apparatus 48 to the electronic processing apparatus 16. As will likewise be set forth in greater detail below, various embodiments are disclosed wherein the temperature and elongation of the fuel pellets 38 are detected in various ways, and wherein the ambient pressure within the interior region 36 of the fuel rod 6 is detected in various ways. It is understood that these properties are not intended to be limiting, and it is also understood that other properties potentially can be detectable without departing from the spirit of the instant disclosure. As can be understood from FIG. 3, the electrical circuit apparatus 44 can be said to include a resonant electrical circuit 50 that operates as a sensor and that includes a plurality of circuit components that include a capacitor 54 and an inductor 56. The circuit components have values or properties, such as the capacitance of the capacitor 54 and the inductance of the inductor 56, by way of example, which are selected to impart to the resonant electrical circuit 50 a unique nominal frequency which, when detected by the interrogation apparatus 48, is usable to identify the particular fuel rod 6 within which the electrical circuit apparatus 44 is situated. In this regard, it is understood that a plurality of instances of the electrical circuit apparatus 44 can be situated in a plurality of corresponding fuel rod 6 of the fuel assembly 10. During operation of the detection apparatus 4, the interrogation apparatus 48 interrogates the electrical circuit apparatus 44 in order to receive a signal from the electrical circuit apparatus 44 that can be interpreted as being indicative of one or more of the properties or conditions within the interior region 36 of the fuel rod 6, such as temperature and/or elongation of the fuel pellets 38, ambient pressure within the interior region 36 of the fuel rod 6, etc., and by way of example. The fuel assembly 10 includes a large number of the fuel rods 6, and a subset of the fuel rods 6 of the fuel assembly 10 are envisioned to each have a corresponding electrical circuit apparatus 44 situated therein. When the interrogation apparatus 48 sends out its interrogation signal, the various electrical circuit apparatuses 44 will responsively output a signal that is transmitted through the cladding 32 or the corresponding fuel rod 6 and is received by the interrogation apparatus 48. The various signals from the various electrical circuit apparatuses 44 each has a unique nominal frequency that is selected by selecting the various properties of the capacitor 54 and the inductor 56, by way of example, of the electrical circuit apparatus 44 in order to provide such a signature frequency. The electric processing apparatus 16 is thus able to use the frequencies of the various detected signals to determine which signal corresponds with which fuel rod 6 of the fuel assembly 10. As can further be understood from FIG. 3, the electrical circuit apparatus 44 additionally includes a resonant electrical circuit 60 that is usable as a calibration circuit. That is, the resonant electrical circuit 50 is usable as a sensor circuit that senses the property or condition within the interior region 36 of the fuel rod 6, and the resonant electrical circuit 60 is usable as a calibration circuit to compensate the signal from the resonant electrical circuit 50 for component degradation, temperature drift, and the like. In this regard, the resonant electrical circuit 60 includes a capacitor 62 and an inductor 66 that are selected to have the same material properties as the capacitor 54 and the inductor 56 of the resonant electrical circuit 50. However, and as will be set forth in greater detail below, the resonant electrical circuit 50 is exposed to the condition that is being measured within the interior region 36, such as the temperature and/or elongation of the fuel pellets 38, and/or the ambient pressure within the interior region 36, by way of example. The resonant electrical circuit 60, being usable as a calibration circuit, is generally not so exposed to the condition being measured. Such calibration is provided by employing a ratiometric analysis such as will be discussed in greater detail elsewhere herein. As can further be understood from FIG. 3, the interrogation apparatus 48 can be said to include a transmitter 68 and a receiver 72. The transmitter 68 is configured to output an excitation pulse 74 which is in the form of a magnetic field signal that is capable of being transmitted through the cladding of the instrument thimble 8 within which the interrogation apparatus 48 is situated and is further capable of being transmitted through the cladding 32 of the fuel rod 6. The excitation pulse 74 is thus receivable by the inductor 56 and the inductor 66 of the resonant electrical circuits 50 and 60, respectively, to induce a resonant current in the resonant electrical circuits 50 and 60 in a known fashion. The induced currents in the resonant electrical circuits 50 and 60 result in the outputting of a response pulse 78 from the resonant electrical circuit 50 and a response pulse 80 from the resonant electrical circuit 60. The responses pulses 78 and 80 are in the form of magnetic field signals, which are not merely radio frequency signals, and which can be transmitted from the electrical circuit apparatus 44 through the cladding 32 and through the cladding of the instrument thimble 8 and thus be received on the receiver 72. The excitation pulse 74 is of a generally sinusoidal configuration. The response pulses 78 and 80 are likewise sinusoidal pulses, but they are decaying sinusoidal signals, and it is noted that FIGS. 5A and 5B depict a pair of traces that are representative of two different response pulses 78. In this regard, the frequency of the response pulse 78 may correlate with one parameters within the fuel rod 6, such as temperature, the peak amplitude of the response pulse 78 may correspond with another parameter within the fuel rod 6, such as elongation of the fuel pellets 38, and a decay rate of the response pulse rate 78 may correlate with yet another parameter within the fuel rod 6, such as ambient pressure within the interior region 36. As such, the response pulse 78 may be correlated with a plurality of parameters or conditions within the interior region 36 of the fuel rod 6 within which the electrical circuit apparatus 44 is situated. The aforementioned ratiometric analysis of the response pulses 78 and 80 typically involves taking a ratio of the response pulse 78 to the response pulse 80 or vice versa, in order to eliminate the effects of component degradation and temperature drift. For instance, the resonant electrical circuits 50 and 60 may degrade over time thus affecting the signal that is output therefrom. Likewise, the signals that are output from the resonant electrical circuits 50 and 60 can vary with temperature of the nuclear reactor 12. In order to compensate for these factors, it is assumed that the resonant electrical circuit 50 and the resonant electrical circuit 60 will degrade at substantially the same rate over time. Furthermore, the resonant electrical circuits 50 and 60 will be exposed to the same gross, i.e., overall, temperature within the interior of the nuclear reactor 12. By taking the ratio of the response pulses 78 and 80, such as the ratio of the frequencies, by way of example, and by using the ratio to look up in the data tables 30 a corresponding value for temperature, elongation, and/or pressure, the individual effects of component degradation and temperature drift in the resonant circuit 50 are eliminated. This is because the ratiometric signal is independent of component degradation and temperature drift since the resonant electrical circuits 50 and 60 are assumed to both experience the same component degradation and temperature drift. As is best shown in FIG. 4, the electrical circuit apparatus 44 further includes a elongation transmission apparatus 84 that is situated within the interior region 36 of the fuel rod 6. The elongation transmission apparatus 84 includes a support 86 that is formed of a ceramic material in the depicted exemplary embodiment and which is abutted against the stack of fuel pellets 38. The support 86 has a receptacle 87 formed therein, and the elongation transmission apparatus 84 further includes an elongated element that is in the form of a ferritic rod 88 and that is received in the receptacle 87. The inductor 56 includes a coil 90 that is situated about and exterior surface of a tube 92 that is formed of a ceramic material. The tube 92 has an interior 94 within which an end of the ferritic rod 88 opposite the support 86 is receivable. As the fuel pellets 38 increase in temperature, they thermally expand, thus causing the fuel pellets 38 to push the support 86 and thus the ferritic rod 88 in a rightward direction in FIG. 4, and thus to be received to a relatively greater extent within the interior 94, which alters the inductance of the inductor 56. Such an alteration of the inductance of the inductor 56 adjusts the frequency of the resonant electrical circuit 50, which is detectable when the excitation pulse 74 excites an electrical resonance in the resonant electrical circuit 50. The response pulse 78 from the resonant electrical circuit 50 thus has a frequency that is indicative of the extent of elongation of the fuel pellets 38. The response pulses 78 and 80 are received by the receiver 72, and the receiver 72 responsively sends a number of signals to the electronic processing apparatus 16. The electronic processing apparatus 16 uses the ratio of the response pulses 78 and 80, or vice versa, to retrieve from the data tables 30 an identity of the fuel rod 6 within which the electrical circuit apparatus 44 is situated, based upon the signature nominal frequency of the response pulses 78 and 80, and additionally retrieves from the data tables 30 a value that corresponds with the extent of elongation of the fuel pellets 38 as exemplified by the response pulse 78. These data can then be sent into a main data monitoring system of the nuclear reactor 12, by way of example, or elsewhere. In this regard, it is noted that the calibration circuit represented by the resonant electrical circuit 60 is not strictly critical for the detection of the properties or conditions such as fuel elongation, center line fuel temperature, and ambient pressure, within the interior of the various fuel rods 6. As such, it is understood that the calibration circuit 60 is optional in nature and is usable in order to simplify the data gathering operation and to overcome limitations associated with component degradation and temperature drift, but the calibration circuit 60 is not considered to be necessary to the operation of the detection apparatus 4. As such, it is understood the various other types of electrical circuit apparatuses in the various other embodiments that are described elsewhere herein may or may not include a calibration circuit without departing from the spirit of the instant disclosure. In this regard, it is noted that the calibration circuit 60 is described only in terms of the electrical circuit apparatus 44, but it is understood that any of the other embodiments of the other electrical circuit apparatuses herein may incorporate such a calibration circuit. As suggested above, the response pulse 78 is a decaying sine wave that has properties such as a peak amplitude, a frequency, and a rate of decay. FIG. 5A depicts a trace 96A of one such response pulse 78, and FIG. 5B depicts another trace 96B of another such response pulse 78. It can be understood from FIGS. 5A and 5B that the trace of FIG. 5A has a greater peak amplitude, a higher frequency (as indicated by the shorter period 98A compared with the period 98B in FIG. 5B), and further has a higher rate of decay than the trace 96B of FIG. 5B. As such, while any one of temperature, pressure, and elongation can be directly measured from the frequency of either of the traces 96A and 96B, it is understood that a plurality of such parameters can be simultaneously derived from each such trace 96A and 96B depending upon the configuration of the routines 28 and the data tables 30, by way of example. It thus can be said that elongation of the fuel pellets 38 can affect the inductance value of the inductor 56 by virtue of the relative movement of the ferritic rod 88 with respect to the coil 90. This affects the frequency of the response pulse 78 that is output by the resonant electrical circuit 50, and which is therefore detectable by the electronic processing apparatus 16 through the use of the routines 28 and the data table 30. FIG. 6 depicts an improved electrical circuit apparatus 144 in accordance with a second embodiment of the disclosed and claimed concept. The electrical circuit apparatus 144 includes a resonant electrical circuit 150 having a capacitor 154 and an inductor 156, and is thus similar in that fashion to the electrical circuit apparatus 44. However, the electrical circuit apparatus 144 includes a temperature transmission apparatus 184 that enables measurement of the center line fuel pellet temperature within the fuel rod 6. Specifically, the temperature transmission apparatus 184 includes a modified fuel pellet 186 that is modified to have a receptacle 187 formed therein. The temperature transmission apparatus 184 further includes a tungsten rod 189 that is an elongated element and that is received in the receptacle 187. While the elongated element 189 is depicted in the exemplary embodiment described herein as being formed of tungsten, it is understood that any of a wide variety of other refractory metals and alloys such as molybdenum and the like can be used in place of tungsten. The temperature transmission apparatus 184 further includes a ferritic rod 188 that is abutted against the tungsten rod 189, it being understood that the tungsten rod 189 is abutted with the modified fuel pellet 186. The inductor 156 includes a coil 190 that is situated directly on the ferritic rod 188. During operation, the heat that is generated by the fuel pellets 38 and the modified fuel pellet 186 is conducted through the tungsten rod 189 and thereafter through the ferritic rod 188, thereby causing the temperature of the ferritic rod 188 to correspond with the temperature of the fuel pellets 38 and the modified fuel pellet 186. The permeability of the ferritic rod 188 changes as a function of temperature, and the change in permeability with temperature is depicted in a graph that is shown generally in FIG. 7. A portion of the graph of FIG. 7 is encircled and demonstrates the temperature that is typically seen by the ferritic rod 188 after the heat from the modified fuel pellet 186 is transferred to the ferritic rod 188 by the tungsten rod 189 and demonstrates, due to the steepness of the curve at the indicated location in FIG. 7, the correlation between temperature of the ferritic rod 188 and permeability thereof. The permeability of the ferritic rod 188 which, as noted, varies as a function of temperature, affects the inductance of the inductor 156 with the result that the frequency of the response pulse 78 that is output by the resonant circuit 150 varies directly with the permeability of the ferritic rod 188 and thus with the temperature of the fuel pellets 38 and the modified fuel pellet 186. As such, the temperature of the fuel pellets 38 and the modified fuel pellet 186 can be measured by detecting the response pulse 78 that is output by the resonant electrical circuit 150 through the use of the routines 28 and the retrieval from the data tables 30 of a temperature that corresponds with the detected frequency of the response pulse 78. An improved electrical circuit apparatus 244 in accordance with a third embodiment of the disclosed and claimed concept is depicted in FIG. 8 and is usable in a fuel rod in a fashion similar to the electrical circuit apparatus 44. The electrical circuit apparatus 244 is receivable in the interior region 36 of the fuel rod 6 and includes a resonant electrical circuit 250 and a temperature transmission apparatus 284 that detect the temperature of a set of modified fuel pellets 286. The modified fuel pellets 286 each have a receptacle 287 formed therein. The temperature transmission apparatus 284 includes an amount of liquid metal 291 that is liquid during operation of the nuclear reactor 12. The temperature transmission apparatus 284 further includes a ferritic rod 288 that is engaged with the liquid metal 291 and is buoyantly floated thereon and is receivable in the interior of a coil 290 of an inductor 256 of the resonant electrical circuit 250. The liquid metal 291 expands and contracts with temperature increases and decreases, respectively, of the modified fuel pellets 286. The position of the ferritic rod 288 with respect to the coil 290 is thus directly dependent upon the centerline temperature of the modified fuel pellets 286. Such position of the ferritic rod 288 with respect to the coil 290 affects the inductance of the inductor 256 and therefore correspondingly affects the frequency of the resonant electrical circuit 250. The response pulse 78 that is generated by the resonant electrical circuit 250 thus is receivable by the receiver 72 and is communicated to the electronic processing apparatus 16, and the routines 28 and the data tables 30 are employed to determine a corresponding temperature of the modified fuel pellets 286 and thus of the corresponding fuel rod 6. FIG. 9 depicts an improved electrical circuit apparatus 344 in accordance with a fourth embodiment of the disclosed and claimed concept. The electrical circuit apparatus 344 is usable inside a fuel rod 6 and includes a resonant electrical circuit 350 and a pressure transmission apparatus 385. The pressure transmission apparatus 385 is configured to enable measurement of the ambient pressure within the interior of the fuel rod 6 and includes a support 386 that abuts the stack of fuel pellets 338. The pressure transmission apparatus 385 further includes a ferritic rod 388 and a vessel in the form of a bellows 393 having a hollow cavity 395 and further having a plurality of corrugations 396 formed therein. The hollow cavity 395 is open and is therefore in fluid communication with the interior region of the fuel rod 6. Moreover, an end of the bellows 393 opposite a ferritic rod 388 is affixed to the support 386. The resonant electrical circuit 350 includes a capacitor 354 and further includes an inductor 356 having a coil 390 that is formed about the exterior of a hollow tube 392 having an interior 394 within which a ferritic rod 388 is receivable. The bellows 393 and the ferritic rod 388 are movably received on a support 386 and are biased by a spring in a direction generally toward the fuel pellets 338. As is understood in the relevant art, as the nuclear reactor 12 is in operation, fission gases are produced that include one or more noble gases. Such fission gases increase the ambient pressure within the interior region of the fuel rod 6. Since the hollow cavity 395 is in fluid communication with the interior region of the fuel rod 6, the increased pressure in the interior region 36 bears upon bellows 393 within the hollow cavity 395 and causes the bellows 393 to expand axially, thereby moving the ferritic rod 388 with respect to the coil 390 and thereby affecting the inductance of the inductor 356. An increase in ambient pressure within the interior region 36 of the fuel rod 6 thus expands the bellows 393, thereby resulting in an incremental further reception of the ferritic rod 388 into the coil 390, which results in a corresponding change in inductance of the inductor 356. The corresponding change in inductance of the inductor 356 affects in a predictable fashion the frequency of the resonant electrical circuit 350 and thus likewise affects the frequency of the response pulse 78 that is output by the resonant electrical circuit 350. As a result, when the response pulse 78 from the resonant electrical circuit 350 is received by the receiver 72 and is communicated to the electronic processing apparatus 16, the routines 28 and the data tables 30 are employed to obtain a corresponding value for the ambient pressure within the interior region 36 of the fuel rod 6. Such value for the ambient pressure can then be communicated to an enterprise data system of the nuclear reactor 12. An improved electrical circuit apparatus 444 in accordance with a fifth embodiment of the disclosed and claimed concept is depicted generally in FIG. 10. The electrical circuit apparatus 444 is situated within an interior region 436 of a fuel rod 6 and includes a resonant electrical circuit 450 that includes a capacitor and an inductor 456. The electrical circuit apparatus 444 further includes a pressure transmission apparatus 485 that includes a vessel in the form of a Bourdon tube 493 which, in the depicted exemplary embodiment, includes a hollow tube that is formed in a helical shape. The hollow tube of the Bourdon tube 493 forms a hollow cavity 495, except that an inlet 497 is formed in an end of the Bourdon tube 493 and thus permits fluid communication with the interior of the Bourdon tube 493. More specifically, the electrical circuit apparatus 444 further includes a support 486 in the form of a seal that extends between the edges of the Bourdon tube 493 adjacent the inlet 497 and extends to an interior surface of the interior region 436 of the fuel rod 6. The support 486 thus divides the interior region 436 into a main portion 481 within which a number of fuel pellets 438 are situated and a sub-region 483 within which the Bourdon tube 493 and the inductor 456 are situated. The Bourdon tube 493 is also supported on the support 486. The support 486 resists fluid communication between the main portion 481 and the sub-region 483, except for the inlet 497 which permits fluid communication between the interior of the Bourdon tube 493 and the main portion 481. The pressure transmission apparatus 485 further includes a ferritic rod 488 that is situated on the Bourdon tube 493 at an end thereof opposite the inlet 497. The inductor 456 includes a coil 490, and movement of the ferritic rod 488 in relation to the coil 490 changes the inductance of the inductor 456 such that the frequency of the response pulse 78 that is generated by the electrical circuit apparatus 444 changes corresponding to the ambient pressure within the main portion 481 of the interior region 436. More specifically, as fission gases accumulate in the main portion 481 of the interior region 436, the ambient pressure within the main portion 481 increases, as does the ambient pressure within the hollow cavity 495 of the Bourdon tube 493. Since the sub-region 483 does not experience the increased ambient pressure that is experienced by the main portion 481, and increase in the ambient pressure within the hollow cavity 495 of the Bourdon tube 493 results in expansion of the Bourdon tube 493 and resultant movement of the ferritic rod 488 in the direction of the arrow 499 with respect to the coil 490. This results in a corresponding change in the frequency of the response pulse 78 that is generated by the electrical circuit apparatus 444. It thus can be seen that changes in ambient pressure within the main portion 481 of the interior region 436 result in a change in inductance of the inductor 456 and a corresponding change in the nominal frequency of the resonant electrical circuit 450 and a resultant change in the frequency of the response pulse 78 that is generated by the electrical circuit apparatus 444. When such response pulse 78 is received by the receiver 72, a corresponding signal is communicated to the electronic processing equipment 16, and the routines 28 and the data tables 30 are used to obtain a corresponding value for the ambient pressure within the interior region 436 for output as desired. An improved electrical circuit apparatus 544 in accordance with a sixth embodiment of the disclosed and claimed concept is depicted generally in FIG. 11. The electrical circuit apparatus 544 is similar to the electrical circuit apparatus 444 in that a Bourdon tube 593 is employed as a vessel having a hollow cavity 595. In the electrical circuit apparatus 544, however, the Bourdon tube 593 includes a plug 597 at an end thereof opposite a ferritic rod 588 such that the hollow cavity 595 of the Bourdon tube is not in fluid communication with the interior region 536 of the fuel rod 6, and an increase in ambient pressure within the interior region 536 causes the Bourdon tube 593 to contract. The Bourdon tube 493 is supported on a support 586 in the vicinity of the plug 597, and a contraction of the Bourdon tube 493 due to increased ambient pressure within the interior region 536 thus moves the ferritic rod 588 in the direction of the arrow 599 with respect to the coil 590. The electrical circuit apparatus 544 includes a resonant electrical circuit 550 having a capacitor and an inductor 556, and movement of the ferritic rod 588 with respect to the coil 590 of the inductor 556 changes the inductance of the inductor 556 and thus changes the nominal frequency of the resonant electrical circuit 550. The electrical circuit apparatus 544 thus includes a pressure transmission apparatus 585 that is similar to the pressure transmission apparatus 485, except that the pressure transmission apparatus 585 includes a Bourdon tube 593 whose hollow cavity 595 is not in fluid communication with the interior region 536 and thus contracts in the presence of an increased ambient pressure within the interior region 536. An improved electrical circuit apparatus 644 in accordance with a seventh embodiment of the disclosed and claimed concept includes a resonant electrical circuit 650 having a capacitor 654 and an inductor. The capacitor 654 includes a pair of plates 652A and 652B that are separated by a dielectric material 653. The electrical circuit apparatus 644 is receivable within the interior region 36 of a fuel rod 6 in order to output a response pulse 78 whose frequency is adjusted responsive to a change in ambient pressure within the interior region 36 of the fuel rod 6. More specifically, the dielectric 653 is hygroscopic in nature and is configured to absorb at least some of the fission gases that are generated during operation of the nuclear reactor 12. Such absorption of the fission gases by the dielectric 653 changes the dielectric constant of the dielectric 653, which adjusts the capacitance of the capacitor 654, with a corresponding effect on the frequency of the response pulse 78 that is generated by the resonant electrical circuit 650. As such, a change in the ambient pressure within the interior region 36 of the fuel rod 6 correspondingly affects the capacitance of the capacitor 654 and thus likewise correspondingly affects the frequency of the response pulse 78 that is generated by the resonant electrical circuit 650. When the response pulse 78 is received by the receiver 72, the receiver 72 responsively provides to the electronic processing apparatus 16 a signal which is used by the routines 28 in conjunction with the data tables 30 to obtain and output a value for the ambient pressure within the interior region 36 of the fuel rod 6 within which the electrical circuit apparatus 644 is situated. An electrical circuit apparatus 744 in accordance with an eighth embodiment of the disclosed and claimed concept is depicted generally in FIG. 13 as being situated within an interior region 736 of a fuel rod 6. The electrical circuit apparatus includes a resonant electrical circuit 750 that includes a capacitor 754 and an inductor 756. The electrical circuit apparatus 744 includes a pressure transmission apparatus 785 that includes a support 786 upon which the capacitor 756 is situated in a stationary fashion and further includes a flexible seal 782. More specifically, the capacitor 754 includes a pair of plates 752A and 752B with a dielectric material 753 interposed therebetween. The plate 752A is situated on the support 786, and the flexible seal extends between the plate 752B and an interior surface of the fuel rod 6 to divide the interior region 736 into a main portion 781 within which a number of fuel pellets 738 are situated and a sub-region 783 within which the inductor 756, the plate 752A, the support 786, and the dielectric 753 are situated. The support 786 is rigid but has a number of openings formed therein such that an increase or decrease in the ambient pressure within the main portion 781 will result in movement of the flexible seal 782 with respect to the support 786. The flexible seal 782 thus resists fluid communication between the main portion 781, which is the location where the fission gases are generated, and the sub-region 783. When the main portion 781 experiences a change in the ambient pressure within the main portion 781, this causes the flexible seal 782 and the plate 752B to move with respect to the plate 752A which, being situated on the support 786, remains stationary. The dielectric material 753 is configured to be at least partially flexible in response to movement of the plate 752B with respect to the plate 752A. However, such movement of the plate 752B with respect to the plate 752A results in a change in the capacitance of the capacitor 754. This results in a corresponding change in the frequency of the response pulse 78 that is generated by the resonant electrical circuit 750 as a result of a change in the ambient pressure within the main portion 781. It thus can be understood that a change in ambient pressure within the main portion 781 of the interior region 736 correspondingly changes the frequency of the response pulse 78 that is received by the receiver 72 and which resultantly communicates a signal to the electronic processing apparatus 16. The electronic processing apparatus 16 then employs its routines 28 and its data tables 30 to determine a pressure value that corresponds with the frequency of the response pulse 78 and which is indicative of the ambient pressure within the main portion 781 of the interior region 736. It thus can be seen that various electrical circuit apparatuses are provided that are able to directly measure parameters such as ambient pressure, centerline fuel pellet temperature, and fuel pellet elongation within the various fuel rods 6 of the fuel assembly 10. As noted, any of the electrical circuit apparatuses can include the calibration circuit that is usable to compensate for component degradation and temperature drift. In addition to the direct measurement of the parameters such as centerline fuel pellet temperature, fuel pellet elongation, and ambient pressure within the interior region of the fuel rods 6, it is reiterated that the response pulse 78 in certain circumstances can be analyzed in terms of its peak amplitude, frequency, and rate of decay in order to indirectly and simultaneously indicate a plurality the same parameters of the fuel rods 6. Other variations will be apparent. 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	The design of a compact, high-efficiency, high-flux capable compact-accelerator fusion neutron generator (FNG) is discussed. FNG's can be used in a variety of industrial analysis applications to replace the use of radioisotopes which pose higher risks to both the end user and national security. High efficiency, long lifetime, and high power-handling capability are achieved though innovative target materials and ion source technology. The device can be scaled up for neutron radiography applications, or down for borehole analysis or other compact applications. Advanced technologies such as custom neutron output energy spectrum, pulsing, and associated particle imaging can be incorporated.
	summary
047626690	summary	CROSS REFERENCE TO RELATED APPLICATIONS Reference is hereby made to the following U.S. patent applications dealing with related subject matter and assigned to the assignee of the present invention: 1. "A Partial Grid For A Nuclear Reactor Fuel Assembly" by Edmund E. DeMario et al, assigned U.S. Ser. No. 564,049 and filed Dec. 21, 1983, now U.S. Pat. No. 4,576,786. 2. "A Low Pressure Drop Grid For A Nuclear Reactor Fuel Assembly" by Edmund E. DeMario et al, assigned U.S. Ser. No. 567,448 and filed Dec. 30, 1983, now abandoned. 3. "A Coolant Flow Mixer Grid For A Nuclear Reactor Fuel Assembly" by Edmund E. DeMario et al, assigned U.S. Ser. No. 567,450, filed Dec. 30, 1983, now U.S. Pat. No. 4,692,302. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to fuel assemblies for a nuclear reactor and, more particularly, is concerned with fuel assemblies positioned adjacent the baffle structure about the periphery of the reactor core which employ annular anti-vibration grids. 2. Description of the Prior Art A typical nuclear power reactor includes a reactor vessel housing a nuclear reactor core. Spaced radially inwardly from the reactor vessel is a generally cylindrical core barrel and within the barrel is a former and baffle system (hereinafter called a baffle structure) which permits transition from the cylindrical barrel to a squared off periphery of the reactor core formed by the fuel assemblies arrayed therein. The reactor core is composed of a large number of elongated fuel assemblies. Each fuel assembly includes a plurality of fuel rods containing the fissile material which reacts to produce heat. The fuel rods of each fuel assembly are held in an organized array by a plurality of grids spaced axially along the fuel assembly length and attached to a plurality of elongated control rod guide thimbles of the fuel assembly. During operation of the reactor, a coolant fluid such as water, is typically pumped into the reactor vessel through a plurality of inlet nozzles. The coolant fluid passes downward through an annular region defined between the reactor vessel and core barrel, turns in a lower plenum defined in the reactor vessel, then passes upwardly through the fuel assemblies of the reactor core, and exits from the vessel through a plurality of outlet nozzles extending through the core barrel. Heat energy which the fuel rods of the fuel assemblies impart to the coolant fluid is carried off by the fluid from the vessel. Due to the existence of holes in the core barrel, coolant fluid is also present between the barrel and baffle structure and at a higher pressure than within the core. However, the baffle structure together with the core barrel do separate the coolant fluid from the fuel assemblies as the fluid flows downwardly through the annular region between the reactor vessel and core barrel. As mentioned above, the baffle structure surrounds the fuel assemblies of the reactor core. Typically, the baffle structure is made of plates joined together by bolts. These bolts sometimes become loose thereby developing a small gap between the baffle structure plates. When this happens, a coolant fluid jetting action takes place through the baffle structure in a radially inward direction from the exterior to the interior thereof due to the greater fluid pressure existing outside of the baffle than within the core. The fluid jetting, when it impinges on the outer row of fuel assemblies in the core, makes their outer fuel rods vibrate, eventually causing them to fail. Consequently, the need exists for a way to deal effectively with fluid jetting through loosened portions of the baffle structure so as to avoid its deleterious effects on the fuel rods of the fuel assemblies positioned adjacent the baffle structure. SUMMARY OF THE INVENTION The present invention provides fuel assemblies with annular anti-vibration grids which are designed to satisfy the aforementioned needs. In particular, the fuel assemblies positioned adjacent the baffle structure about the periphery of the reactor core employ annular anti-vibration grids inserted between the regular grids and anchored to the guide thimbles like the regular grids. The annular grids will only occupy the space about the outer three rows of fuel rods in the fuel assemblies positioned at the core periphery. The grids will retard or dampen vibration of the fuel rods in these outer rows. Specifically, the presence of the annular grid reduces the length of the span of the fuel rods being unsupported between the regular grids, while also changing their vibrational frequency, thereby preventing the fuel rod damage experienced heretofore from vibrations caused by the coolant fluid jetting action through the baffle structure. In such manner, the deleterious effects of fluid jetting through the baffle structure will be substantially avoided. The fuel assemblies having the annular grids are only placed in core locations most susceptible to coolant fluid jetting action through the baffle structure. Since the number of such fuel assemblies will be small, the impact of the presence of the annular grids on overall core pressure drop will be small. Also, since these outside peripheral locations typically have small relative power, the fuel assemblies using these grids will not become DNB limiting. In instances where intermediate flow mixer grids, such as disclosed in the third application cross-referenced above, are already present between the regular grids in the top half of the fuel assemblies, the annular anti-vibration grids will only be used in the bottom half of the fuel assemblies. Accordingly, the present invention is directed to an improvement in a nuclear reactor fuel assembly. The fuel assembly includes a top nozzle, a bottom nozzle, and a plurality of guide thimbles extending longitudinally between and connected at their opposite ends to the top and bottom nozzles. The fuel assembly also has a multiplicity of elongated fuel rods and a plurality of support grids axially spaced along and supported by the guide thimbles. Each of the support grids defines a multiplicity of cells at least equal in number to the multiplicity of fuel rods for receiving respective ones of the fuel rods therethrough and supporting the fuel rods in a side-by-side array with respect to one another and to the guide thimbles. The improvement comprises a plurality of annular anti-vibration grids axially spaced along and connected to the guide thimbles between at least some of the support grids. The annular grids are separate from and unconnected to the support grids. Each of the annular grids defines a plurality of cells being less in number than the multiplicity of fuel rods but at least equal in number to a plurality of the fuel rods positioned along the periphery of the multiplicity of fuel rods. The annular grid cells receive therethrough respective ones of the fuel rods in the plurality thereof and engage these fuel rods so as to dampen any coolant fluid cross flow vibration induced therein. Furthermore, each of the annular grids is composed of a plurality of interleaved members arranged in an egg-crate configuration to define the plurality of cells and a central void region of a size to receive therethrough the rest of the fuel rods in the multiplicity thereof. Each of the annular grids includes a plurality of protrusions formed on the members and projecting into each of the cells in the plurality thereof through a sufficient distance to contact opposing sides of the fuel rod received through each cell. Also, a number of sleeves adapted to receive a like number of the guide thimbles therethrough are connected to the members. The number of the guide thimbles is less than the plurality thereof. The sleeves are unconnected with, and shorter in length than the distance between, the ones of the support grids disposed adjacent to each annular grid. Also, the present invention is directed to the combination in a nuclear reactor, comprising: (a) a reactor core composed of a plurality of fuel assemblies disposed in side-by-side spaced relationships, a first group of the fuel assemblies defining the periphery of the core and a second group of the fuel assemblies positioned inwardly of the first group thereof: (b) each of the fuel assemblies having a plurality of elongated guide thimbles, a multiplicity of elongated fuel rods, a plurality of support grids axially spaced along and supported by the guide thimbles, each of the support grids defining a multiplicity of cells at least equal in number to the multiplicity of fuel rods for receiving respective ones of the fuel rods therethrough and supporting the fuel rods in a side-by-side array with respect to one another and to the guide thimbles; (c) a baffle structure extending about the reactor core adjacent to the fuel assemblies in the first group thereof, the baffle structure having components being subject to unpredictable loosening with respect to one another so as to permit jetting of coolant fluid from the exterior to the interior of the baffle structure and impingement upon fuel rods in the fuel assemblies of the first group thereof so as to cause vibration of the fuel rods; and (d) a plurality of annular anti-vibration grids axially spaced along and connected to the guide thimbles of the fuel assemblies in the first group thereof between at least some of the support grids of the fuel assemblies in the first group thereof, the annular grids being separate from and unconnected to the support grids. Each of the annular grids defines a plurality of cells being less in number than the multiplicity of fuel rods of each of the fuel assemblies in the first group thereof but at least equal in number to the plurality of the fuel rods positioned along the periphery of the each fuel assembly in the first group thereof for receiving respective ones of said fuel rods therethrough and engaging the fuel rods so as to dampen vibration thereof due to impingement by coolant fluid jetting from the baffle structure.
054065950	abstract	A device for closing and sealing a lead-through (1), comprising means intended to open, clean and again close the lead-through. A cone (2) with a head (21), a rod-shaped part (22) and a sealing surface (23) arranged between said head and said rod-shaped part is arranged with the head inserted into the lead-through. In the end of the cone opposite to the head, the cone is provided with means (24) for connecting the cone to a flush pipe (5) arranged in the form of an extension of the rod-shaped part of the cone. An annular flange (3) is attached to the lead-through and around said rod-shaped cone, inserted into the lead-through, to retain the head of the cone in the lead-through. A sealing surface (31), arranged on the annular flange in the form of a seat, is adapted to correspond to and make contact with the sealing surface of the cone to close and seal the lead-through.
041347897	claims	1. A device for refuelling a nuclear reactor, comprising a pressure vessel having a top closure head with a core constituted by a plurality of vertical fuel assemblies an upper internal structure above said reactor core comprising at least one top plate whose periphery rests on a support ledge of said pressure vessel, a plurality of hollow vertical guide tubes in which the control rods are slidably fitted, each control rod being constituted by a plurality of absorber pins coupled by a rigid structure to the lower end of a drive shaft, said shaft being adapted to traverse the top plate aforesaid through an aperture formed opposite to each guide tube and said closure head, a cylindrical canister open at the upper end cemented to said rigid structure, radial ribs fixed on said canister, the wall of said canister being provided with bored recesses for normally accommodating a first series of balls which are capable of projecting from said canister and penetrating to a partial extent into first cooperating notches formed in the top plate aforesaid, wherein said drive shaft is hollow and provided at the lower end which penetrates into said canister with bored recesses for normally accommodating a second series of balls which are capable of projecting from said drive shaft so as to penetrate to a partial extent into second cooperating notches formed in the internal wall of said canister, and wherein said device comprises a movable member with cam means thereon for selectively engaging the balls of the first and second series, one series at a time, for causing alternate penetration of the balls of the first series into the first cooperating notches so as to couple the absorber pins with said upper internal structure and the balls of the second series into the second cooperating notches so as to couple said drive shaft with said canister, whereby when engagement of the cam means is shifted from one series of balls to the other penetration of the engaged balls into their cooperating notches will simultaneously take place with accommodation of the non-engaged balls into their bored recesses. 2. A device according to claim 1, wherein said movable member is constituted by a sleeve whose lower portion is capable of sliding within the interior of said canister and whose upper portion is capable of sliding within the interior of the lower end of the drive shaft, and means for displacing said sleeve in vertical motion, the external profile of the upper portion and the lower portion of said sleeve being such that said portions perform a cam function which permits the alternate motion of said balls. 3. A device according to claim 2, wherein said vertical displacement means are constituted by a vertical operating-rod which is capable of sliding and rotating within the interior of the hollow drive shaft and by a threaded component adapted to cooperate with a threaded portion formed in the lower portion of said canister, the lower end of said sleeve being supported on the top face of the threaded component, said component being coupled for rotation to the lower end of said operating-rod. 4. A method for refuelling a nuclear reactor of the type comprising a pressure vessel having a closure head and an upper internal structure which surmounts the reactor core and contains a plurality of apertures in the tope plate thereof, a plurality of control rods, each of which includes a plurality of absorber pins coupled by a rigid structure to the lower end of a drive shaft which is adapted to traverse said top plate through one of said apertures, the method comprising the following steps: (a) moving the control rods upward, (b) moving a movable member with first and second cam means for simultaneously: (1) remotely securing the absorber rods to the upper internal structure by engaging the first cam means with a first series of balls, located in bored recesses in an open-topped cylindrical canister connected to said rigid structure, so that said first series of balls will move and penetrate to a partial extent into cooperating notches in said top plate, and (2) disconnecting the drive shaft from the absorber rods by engaging the second cam means with a second series of balls, located in bored recesses in said drive shaft and which penetrate to a partial extent into cooperating notches formed in the internal wall of said canister, so that said second series of balls will withdraw from said notches in the internal wall of the canister, (c) removing the reactor closure head with drive shaft independent of the absorber rods and upper internal structure, (d) removing and storing the assembly constituted by the control rods and the upper internal structure, (e) replacing the spent fuel, and (f) returning the upper internal structure and the closure head to their initial positions. (a) raising the control rols by moving the drive shafts upward, (b) while the closure head is in place, moving the drive shaft for simultaneously remotely (1) securing the rigid structure to the upper internal structure and (2) disconnecting the drive shaft from the rigid structure, the rigid structure, on the one hand, and the drive shaft and upper internal structure, on the other hand, having at least two cooperating connecting means located and shaped so that movement of the drive shaft from above the closure head will simultaneously perform steps (1) and (2), (c) removing the reactor closure head with the drive shaft independent of the absorber rods and upper internal structure, (d) removing and storing the assembly constituted by the control rods and the upper internal structure, (e) replacing the spent fuel, and (f) returning the upper internal structure and the closure head to their initial positions. 5. A method for refuelling a nuclear reactor of the type comprising a pressure vessel having a closure head, an upper internal structure which surmounts the reactor core and includes a top plate, a plurality of guides in the top plate, a plurality of control rods, each of which includes a plurality of absorber pins releasably coupled by a rigid structure to the lower end of a drive shaft which is adapted to traverse said top plate through one of said guides, the method comprising the following steps:
063296640	claims	1. An ion implantation apparatus which is provided with a wafer disc having a plurality of wafer holders to support a plurality of wafers, and which carries out ion implantation for each wafer, while said wafer disc executes rotational and reciprocating movements, said apparatus comprising: a control means having holder arms capable of expanding and contracting in the radial direction for controlling the wafer holders by reciprocating motions in the radial direction of the wafer disc such that said plurality of wafer supported on said wafer holders are subjected to ion beam irradiation, while said plurality of wafer holders are designed such that they can move in the radial direction of the wafer disc. holder arms connected to said plurality of wafer holders and which are designed so as to be extendable and contractable in the radial direction of the disc; and a driving means for driving said holder arms to extend or to contract automatically. a center of gravity adjusting means for adjusting the center of gravity of the disc so as to coincide with the position of the disc center. 2. An ion implantation apparatus according to claim 1, wherein said apparatus further comprises: 3. An ion implantation apparatus according to claim 1, wherein said apparatus further comprises: 4. An ion implantation apparatus according to claim 1, wherein, when said control means judges that a plurality of ion dose types are required for untreated wafers in a batch, and the number of untreated wafers is less than the number of wafer holders, said control means forms a plurality of concentric circular regions corresponding to the number of dose types by shifting the positions of the wafer holders, and ion implantation is executed by changing a speed of the reciprocating motions of the wafer holders using an intermediate region as the transition region of the speed change.
	description	The present invention relates to a nuclear fuel assembly for a boiling water reactor. U.S. Pat. No. 5,572,560 discloses a nuclear fuel assembly comprising a bundle of fuel rods with a spacing between the fuel rods varying along the length of the fuel assembly from a uniform pitch at the bottom part of the fuel assembly to a non-uniform pitch at the top part of the fuel assembly to allow accommodation between the fuel rods of a water channel having an increased cross-section in the top part of the nuclear fuel assembly. Provision of the water channel having an increased cross-section in the upper part is intended to enhance neutronic efficiency in terms of equalized water-to-fuel ratio for all fuel rod positions. However, critical power performance is not considered and may be hindered by such arrangement. An object of the invention is to provide a nuclear fuel assembly reaching a good compromise between neutronic efficiency and critical power performance. To this end, a nuclear fuel assembly for a boiling water reactor is provided comprising a bundle of fuel rods comprising a set of fuel rods arranged in a first lattice having a non-uniform pitch between fuel rods in the lowermost section of the fuel assembly, the fuel rods of the set being arranged in a second lattice with a uniform pitch between the fuel rods in the uppermost section of the fuel assembly. According to other embodiments, the nuclear fuel assembly comprises one or several of the following features, taken in isolation or in any technically possible combination: the spacings between the fuel rods of the set vary monotonously along the length of the fuel assembly; in the lowermost section, the fuel rods of the set of fuel rods are arranged in groups separated by coolant/moderator gaps; the fuel rods of each group are in a regular lattice arrangement; the fuel rods of each group are with a uniform pitch between the fuel rods of the group; the coolant/moderator gaps are wider than the passages between the fuel rods or rows of fuel rods of each group; the nuclear fuel assembly comprises at least one coolant/moderator gap extending substantially radially from a central region of the bundle of fuel rods towards the periphery thereof; the nuclear fuel assembly comprises at least one annular coolant/moderator gap; the nuclear fuel assembly comprises at least two coolant/moderator gaps extending parallel to each other; the nuclear fuel assembly comprises at least one tubular water channel replacing at least one fuel rod in the bundle of fuel rods; the water channel is surrounded by the at least one annular coolant/moderator gap; the water channel is of constant cross section along the length of the fuel assembly; the nuclear fuel assembly comprises at least one individual fuel rod offset from the first lattice in the lowermost section and/or from the second lattice in the uppermost section of the fuel assembly; the transition zone between the lowermost section with a non-uniform pitch towards the uppermost section with a uniform pitch is positioned at a height comprised between 30% and 70% of the height of the fuel assembly active zone; and all the fuel rods are full-length fuel rods. As illustrated on FIG. 1, the nuclear fuel assembly 2 is elongated along a longitudinal axis L. In use, the fuel assembly 2 is placed on the core bottom of a nuclear reactor and the longitudinal axis L extends substantially vertically. In the following, the terms of orientation such as “top”, “bottom”, “lower”, “upper”, “longitudinal”, “transversal” and “vertical” are used with reference to the use position with the longitudinal assembly axis L extending vertically. The nuclear fuel assembly 2 comprises a bundle of fuel rods 4 extending longitudinally. The fuel rods 4 are typically of uniform length. Each fuel rod 4 is of constant cross section. Each fuel rod 4 comprises a tubular cladding filled with stacked nuclear fuel pellets, constituting the fuel assembly active zone, and is closed at its ends by end plugs. The fuel rods 4 are arranged in a lattice. The fuel rods 4 exhibit the same cross section. In an alternative embodiment, fuel rods 4 exhibit different cross sections. The nuclear fuel assembly 2 comprises spacer grids 6 distributed along the length of the fuel rods 4. The spacer grids 6 maintain the fuel rods 4 in spaced relationship in a lattice arrangement and support the fuel rods 4 transversally and longitudinally. The fuel rods 4 conventionally extend through apertures of the spacer grids 6 in contact with springs and/or bosses protruding from the side walls of the apertures for supporting the fuel rods 4. The nuclear fuel assembly 2 comprises a lower nozzle 8 and an upper nozzle 10 provided respectively at the bottom end and upper end of the nuclear fuel assembly 2. The fuel rods 4 extend from the lower nozzle 8 to the upper nozzle 10. The nuclear fuel assembly 2 is of the type adapted for use in a boiling water reactor (BWR). More specifically, the nuclear fuel assembly 2 comprises a tubular water channel 12 extending longitudinally in place of at least one fuel rod 4 in the lattice of fuel rods 4. The water channel 12 is provided for channeling a coolant/moderator (e.g. water) separately from the bundle of fuel rods 4. The water channel 12 has a constant cross section along its length. In an alternative embodiment, the water channel 12 has a cross section varying along the water channel 12. The water channel 12 conventionally connects the lower nozzle 8 and the upper nozzle 10. The spacer grids 6 are conventionally secured to the water channel 12. The nuclear fuel assembly 2 further comprises a tubular fuel channel 14 extending longitudinally and encasing the bundle of fuel rods 4 and the water channel 12. The fuel channel 14 is provided for conducting the coolant/moderator (e.g. water) within the bundle, between and about the fuel rods 4. In the example illustrated on FIGS. 1-4, the fuel rods 4 are arranged in a 10×10 array. The water channel 12 replaces a 3×3 array of fuel rods 4. The water channel 12 is off-centred with respect to the fuel channel 14. In the embodiment illustrated on FIG. 5, the water channel 12 replaces a 3×3 array at the centre of a 11×11 array. In use, the nuclear fuel assembly 2 is positioned vertically inside the core of a nuclear reactor and coolant/moderator is fed in the water channel 12 and the fuel channel 14 through the lower nozzle 8 towards the upper nozzle 10, as illustrated on FIG. 1 by arrow F. The coolant/moderator is progressively partially vaporized when flowing about the fuel rods 4. The proportion of vapour increases from bottom to top with respect to liquid. The void content in the coolant/moderator increases progressively from bottom to top. In the following, spacing or pitch between adjacent fuel rods refer to spacing or pitch between the centrelines of adjacent fuel rods. A lattice, array or group of fuel rods with a uniform pitch designates a lattice, array or group of fuel rods arranged at nodes of a lattice with the same spacing between each pair of adjacent nodes. A lattice, array or group of fuel rods with a non-uniform pitch designates a lattice, array or group of fuel rods arranged at nodes of a lattice with a non-uniform distribution of nodes in the lattice and different spacings between the pairs of adjacent fuel rods. According to one aspect of the invention, the fuel rods 4 are arranged in a first lattice with a non-uniform pitch between fuel rods 4 at the lowermost section of the nuclear fuel assembly 2 (FIG. 2) and in a second lattice with a uniform pitch P between fuel rods 4 at the uppermost section of the nuclear fuel assembly 2 (FIG. 3). Owing to the modification of the overall lattice arrangement of the bundle of fuel rods 4 along the length of the fuel assembly 2, the spacing between at least some of the fuel rods 4 varies along the length of the fuel assembly 2. Preferably, the spacing varies monotonously along the length of the fuel assembly. The pitch between each pair of adjacent fuel rods either is constant or increases or decreases along the length of the fuel assembly. FIG. 2 is a cross sectional view of the lowermost section of the nuclear fuel assembly 2 along II-II in FIG. 1. In this lowermost section, the fuel rods 4 are arranged in a first lattice having a non-uniform pitch. The spacing between the centrelines of the adjacent fuel rods 4 differs between at least some pairs of fuel rods 4. As illustrated, the fuel rods 4 are gathered in groups 16 of fuel rods 4, each group 16 having a uniform pitch between its fuel rods 4. The fuel rods 4 of each group 16 are arranged in a regular square lattice arrangement with a uniform pitch P1 between the fuel rods 4 in both directions of the lattice arrangement. Coolant/moderator gaps 18 are defined between the groups 16 of fuel rods 4. Each pair of adjacent groups 16 is separated by a coolant/moderator gap 18 extending between the facing fuel rods 4 of said two groups 16. The adjacent fuel rods 4 of two different groups 16 delimiting a coolant/moderator gap 18 have a spacing P2 different from the pitch P1 between fuel rods 4 of each group 16. Preferably, the spacing P2 between the fuel rods 4 of different groups 16 delimiting a coolant/moderator gap 18 is higher than the pitch P1 between the fuel rods 4 of each group 16. As a result, each pair of adjacent groups 16 are separated by a coolant/moderator gap 18 which has a width greater than the passages between the rows of fuel rods 4 of each of groups 16. FIG. 3 is a cross sectional view of the uppermost section of the nuclear fuel assembly 2 along III-III in FIG. 1. In the uppermost section, the fuel rods 4 are arranged in a second lattice having a uniform pitch P which is the same between each pair of adjacent fuel rods 4. In the illustrated embodiment, the second lattice in the uppermost section is a regular square lattice. The invention is not limited to 10×10 bundle of fuel rods. The bundle of fuel rods may comprise a different amount of fuel rods 4 in a square array (e.g. 8×8, 9×9 . . . 13×13) or have any other array pattern such as rectangular array or hexagonal array. The invention is not limited to a single water channel replacing a 3×3 array of fuel rods. The water channel may exhibit a square cross section replacing another amount of fuel rods (2×2, 3×3, 4×4 . . . ) or a different cross section, e.g. a rectangular or round cross section. The nuclear fuel assembly may comprise more than one water channel or an alternative water structure, e.g. two or more separate water channels or water rods. In the embodiment illustrated on FIG. 2, the 10×10 bundle of fuel rods 4 is divided in four groups 16 each of 5×5 array with one fuel rod at each node (except for the locations replaced by the water channel 12) separated by four coolant/moderator gaps 18. Each coolant/moderator gap 18 extends substantially radially from the water channel 12 towards the centre of a face of the fuel channel 14. Coolant/moderator gaps may be defined with various other patterns. In a variant illustrated on FIG. 4, an annular coolant/moderator gap 20 is formed in the bottom section of the nuclear fuel assembly 2 between an annular peripheral group 22 of fuel rods 4 and a central group 24 of fuel rods 4. In this example, the peripheral group 22 comprises two rows of fuel rods 4 and the central group 24 is defined by the central 6×6 array in the lattice. The water channel 12 replaces a 3×3 array in the central group 24. Two adjacent sides of the water channel 12 are separated from the peripheral group 22 by two rows of fuel rods 4 and the two remaining adjacent sides of the water channel 12 are separated from the peripheral group 22 by a single row of fuel rods 4. The fuel rods 4 of the peripheral group 22 are arranged in a regular square lattice arrangement with a uniform pitch P3 between the fuel rods 4. The fuel rods 4 of the central group 24 are arranged in a regular square lattice arrangement with a uniform pitch P4 between the fuel rods 4. The adjacent fuel rods 4 of the groups 22, 24 have a spacing P5 between them in the transverse direction of the lattices of the groups 22, 24. In a variant illustrated on FIG. 5, the bundle of fuel rods 4 comprises coolant/moderator gaps 30 extending parallel to each other in the lowermost section of the nuclear fuel assembly 2. More specifically, in the example of FIG. 5, the nuclear fuel assembly 2 comprises a bundle of fuel rods 4 arranged in an 11×11 array and a water channel 12 replacing the central 3×3 array. The bundle is subdivided in four corner groups 26 of fuel rods 4 in a 5×5 array in the corners of the bundle. Each pair of corner groups 26 are separated by an intermediate group 28 of fuel rods 4 in a 4×1 array. Two parallel coolant/moderator gaps 30 are provided on each side of each intermediate group 28, between the intermediate group 28 and each adjacent corner group 26. The fuel rods 4 of each corner groups 26 are arranged in a regular square lattice arrangement with a uniform pitch P6. The spacing P7 between the fuel rods 4 of each intermediate groups 28 and the adjacent fuel rods 4 of the adjacent corner groups 26 is the same. Each pair of adjacent parallel coolant/moderator gaps 30 are separated by a single row of fuel rods 4. In an alternative, two parallel coolant/moderator gaps may be separated by an intermediate group of fuel rods comprising two or more rows of fuel rods. In the embodiment illustrated on FIGS. 2, 4 and 5, the pitches of the different groups 16 are equal and the spacings between the adjacent groups 16 are equal. In alternative or in option, the groups may have different pitches and/or the spacings between the groups may be different. Besides, in the embodiment illustrated on FIGS. 2, 4 and 5, each group 16, 22, 24, 26, 28 has a uniform pitch with fuel rods 4 in a regular square lattice arrangement. In alternative or in option, the fuel rods of at least one group 16, 22, 24, 26, 28 may be arranged in a different regular lattice arrangement yet with a non-uniform pitch, e.g. in a rectangular lattice arrangement with two different pitches in two transverse direction of the lattice. The spacing variation between the fuel rods may be operated continuously along the length of the fuel assembly, step-by-step or abruptly. In any case, the pitch variation is operated monotonously from the non-uniform pitch lowermost section of the nuclear fuel assembly towards the uniform pitch uppermost section of the nuclear fuel assembly. The pitch variation or a step of pitch variation may be operated in the span between two adjacent spacer grids 6. FIG. 6 illustrates an embodiment in which the pitch variation is operated in a single step in the span between two adjacent spacer grids 6. The spacer grids below the pitch variation define apertures for the fuel rods in the lattice with the non-uniform pitch and the spacer grids above the pitch variation define apertures for the fuel rods in the lattice with the uniform pitch. A nuclear fuel assembly according to the invention enables reaching a good compromise between neutronic efficiency, i.e. maximizing the total fission rate over the fuel assembly cross section and thereby maximizing reactivity, and critical power performance, i.e. the maximum fuel assembly power possible before the coolant film around the fuel rods is interrupted, thus potentially leading to damage of fuel rods. Typically, fuel rods having a certain U-235 enrichment and adjacent to large coolant/moderator areas, e.g. outer row fuel rods or fuel rods next to a water channel, have larger power than fuel rods surrounded by others fuel rods. Besides, in the BWR nuclear fuel assembly, coolant is progressively partly converted to vapour when flowing through the nuclear fuel assembly upwardly, whereby void content in the coolant flow increases progressively upwardly and fuel rod cooling becomes less efficient. Non-uniform pitch arrangements between the fuel rods allow providing an inhomogeneous distribution of coolant. Namely, the non-uniform pitch allows providing wider coolant/moderator gaps resulting in more coolant being directed into coolant/moderator gaps about the fuel rods adjacent to the coolant/moderator gaps and less coolant directed about fuel rods not adjacent to a coolant/moderator gap. Proportional to the amount of coolant/moderator around the fuel rods the number of thermal neutrons increases thus leading to an increased fission rate and consequently to an improved fuel utilization. In particular, coolant/moderator gaps are positioned proximate the middle fuel rod rows where the local fuel rod power is usually the highest in the bundle and the coolant/moderator gaps are most effective. The uniform fuel rod pitch in the uppermost section increases critical power performance of the nuclear fuel assembly. As a matter of fact, void content of the coolant is increased in the uppermost section and cooling becomes less efficient in general. The uniform fuel rod pitch favours a uniform coolant distribution in the uppermost section. It is assumed that regarding critical power performance a homogeneous coolant distribution in the uppermost section of the fuel assembly where coolant is high voided is preferable. Conversely, generating coolant/moderator gaps in the uppermost section would lead to less coolant around fuel rods not adjacent to a coolant/moderator gap whereby critical power would be reduced which degrades the overall fuel efficiency of a fuel assembly. Besides the neutronic efficiency benefit of an inhomogeneous coolant distribution is becoming smaller with increasing void content in the coolant. The positive neutronic effect provided by non-uniform pitch is kept in the lowermost section where detrimental effect on critical power performance is small. Thus, an inhomogeneous fuel rod pitch in the lowermost section of the nuclear fuel assembly and a homogeneous fuel rod pitch in the uppermost section is a good compromise between neutronic efficiency and critical power performance, more particularly when the transition zone between the lowermost section with a non-uniform pitch towards the uppermost section with a uniform pitch is positioned at a height comprised between 30% and 70% of the height of the fuel assembly active zone. Indeed, the transition zone from the lowermost section with fuel rods in a non-uniform pitch lattice towards the uppermost section with a uniform pitch lattice of the nuclear fuel assembly should be located in the fuel active zone wherein the net fuel consumption gain by dry-out performance and neutronic efficiency is maximized. Such pitch variation may be located around the centre of the axial active zone but such transition zone from the lowermost section with a non-uniform pitch lattice towards the uppermost section with a uniform pitch lattice of the nuclear fuel assembly will furthermore depend on the chosen axial spacer grid positions between the lower and upper nozzles. The invention is particularly advantageous for nuclear fuel assembly of the BWR type. In the embodiments illustrated in FIGS. 1-6, the fuel rods are full-length fuel rods of substantially the same length. In an alternative embodiment, the bundle of fuel rods comprises part-length fuel rods of shorter length than the full-length fuel rods. Possibly there may be different kinds of part-length fuel rods, i.e. differing in length. The fuel rods (including both the part-length fuel rods and the full-length fuel rods) are arranged in a first lattice with a non-uniform pitch at the lowermost section of the nuclear fuel assembly. Depending on the total length of the part-length fuel rods, the lattice with the uniform pitch in the uppermost section of the fuel assembly can either include only the remaining full-length rods or additionally all or a portion of the part-length rods. In the embodiments of FIGS. 1-6, all the fuel rods are arranged in the first lattice with a non-uniform pitch at the lowermost section and in the second lattice with a uniform pitch at the uppermost section. In an alternative embodiment, the bundle of fuel rods comprises at least one individual fuel rod which is offset with respect to a pitch in the lowermost lattice and/or from the uniform pitch of the second lattice in the uppermost section of the nuclear fuel assembly, thus creating a local non-uniformity. Such a fuel rod is for example a fuel rod located at a corner of the bundle which is offset towards the centre of the bundle in order to maintain a certain clearance between said fuel rod and the fuel channel. However, except from the offset fuel rods creating local non-uniformity, the fuel rods of the remaining set of fuel rods are arranged in a first lattice of non-uniform pitch in the lowermost section and in a second lattice with a uniform pitch in the uppermost section. Hence, in a general manner, the nuclear fuel assembly comprises a bundle of fuel rods comprising at least a set of fuel rods arranged in a first two dimensional lattice of non-uniform pitch in the lowermost section and in a second two dimensional lattice of uniform pitch in the uppermost section of the nuclear fuel assembly. The alternatives mentioned above may be combined thus providing a bundle of fuel rods comprising full-length and part-length fuel rods as well as locally offset individual fuel rods.
	abstract	A light-weight radiation protection panel comprising radiation protection layer and a flexible material. The radiation protection layer comprises a plurality of a shielding material distributed in repeated and adjacent units of geometrical shapes, the light-weight radiation protection panel being able to be embodied in a wearable garment providing flexibility.
	summary
	abstract	A light source is gated ON and OFF in response to a pulsed signal. Photo emissions from the light source are coupled to a material under test. Resonant fluorescent emissions from the material are coupled to a photodiode. Current from the photodiode is coupled into an amplifier system comprising a first and second amplifier stages. The first amplifier stage is gated to a low gain when the light source is turned ON and the gain is increased when the light source goes from ON to OFF. The second amplifier stage has digitally programmable offset and gain settings in response to control signals. The output of the second amplifier stage is digitized by an analog to digital converter. A controller generates the pulse control signal and the control signals.
	claims	1. A drawing apparatus that performs drawing on a substrate with a plurality of charged particle beams, the drawing apparatus comprising:an electron lens positioned at a location facing opposite to the substrate and including a plurality of holes through which the charged particle beams pass; anda cleaning unit configured to release active species to a decomposition product that has adhered to the electron lens and reduce the decomposition product by the reaction of the active species and the decomposition product to thereby change the decomposition product to a volatile gas,wherein the cleaning unit has a plurality of openings formed such that the active species are released toward the plurality of holes of the electron lens, andwherein each opening of the cleaning unit is disposed opposite to each of the holes. 2. The drawing apparatus according to claim 1, wherein each opening of the cleaning unit is configured concentrically with the holes corresponding to the electron lens. 3. The drawing apparatus according to claim 1, wherein the cleaning unit comprises a main body that is opened such that a plane facing opposite to the electron lens is capable of being connected to a fixing unit for supporting the electron lens, and the main body comprises an opening array having the plurality of openings provided in the plane. 4. The drawing apparatus according to claim 3, wherein the cleaning unit comprises a drive mechanism that drives the opening array so as to align the position of the openings with the position of the holes. 5. The drawing apparatus according to claim 3, further comprising:a substrate holding unit configured to place the substrate to be treated and be movable based on the drawing position; anda controller configured to control the operation of the substrate holding unit and the cleaning unit,wherein the cleaning unit comprises a post unit that supports the main body and is capable of moving the main body toward the fixing unit, andwherein, when the active species are released, the controller moves the substrate holding unit from the drawing position, and then moves the post unit toward the fixing unit to thereby bring the main body into connection with the fixing unit. 6. The drawing apparatus according to claim 3, wherein, when the main body is brought into connection with the fixing unit, the distance from the opening to the deepest part of the electron lens is shorter than the mean free path of the active species at the maximum pressure in a region from the openings to the electron lens. 7. The drawing apparatus according to claim 1, wherein the number of openings is equal to the number of holes or is greater than the number of holes. 8. An article manufacturing method, comprising:performing, in a performing step, drawing on a substrate with a plurality of charged particle beams using a drawing apparatus; anddeveloping, in a developing step, the substrate on which the drawing has been performed in the drawing step,wherein the drawing apparatus comprises:an electron lens positioned at a location facing opposite to the substrate and including a plurality of holes through which the charged particle beams pass; anda cleaning unit configured to release active species to a decomposition product that has adhered to the electron lens and reduce the decomposition product by the reaction of the active species and the decomposition product to thereby change the decomposition product to a volatile gas,wherein the cleaning unit has a plurality of openings formed such that the active species are released toward the plurality of holes of the electron lens, andwherein each opening of the cleaning unit is disposed opposite to each of the holes.
	summary
	abstract	A passive containment cooling and filtered venting system includes: an outer well; a scrubbing pool arranged in the outer well; a cooling water pool installed above the dry well and the outer well; a heat exchanger partly submerged in the cooling water; a gas supply pipe that is connected to the inlet plenum of the ruin of the heat exchanger at one end and connected to a gas phase region of the containment vessel at the other end; a condensate return pipe that is connected to the outlet plenum of the heat exchanger at one end, and connected to inside the containment vessel at other end; and a gas vent pipe that is connected to the outlet plenum of the heat exchanger at one end and is submerged in the scrubbing pool at other end.
	claims	1. A spent nuclear fuel assembly storage container comprising:a metal cask which stores a spent nuclear fuel assembly therein;a container body which stores the metal cask and has a substantially hexagonal tubular shape; anda concave portion which is formed on an outer surface of the container body having the substantially hexagonal tubular shape, is recessed inward, and extends in a longitudinal direction,wherein the concave portion forms an external cooling passage for a cooling gas when an outer surface of the container body is joined to an outer surface of another container body. 2. The spent nuclear fuel assembly storage container according to claim 1,wherein an inner surface of the container body is provided with a stopper which prevents vibration of the metal cask. 3. The spent nuclear fuel assembly storage container according to claim 1,wherein an upper surface of the container body is provided with a tapered chimney. 4. The spent nuclear fuel assembly storage container according to claim 1,wherein the container body is made of heavy-weight concrete having a specific gravity of 3.5 or more. 5. A spent nuclear fuel assembly storage container comprising:a metal cask which stores a spent nuclear fuel assembly;a container body which stores the metal cask and has a substantially hexagonal tubular shape; andan internal cooling passage which is provided between the metal cask and an inner surface of the container body and is provided with a cooling gas supply passage and an exhaust passage communicating with external air at upper and lower portions thereof. 6. The spent nuclear fuel assembly storage container according to claim 5,wherein an inner surface of the container body is provided with a stopper which prevents vibration of the metal cask. 7. The spent nuclear fuel assembly storage container according to claim 5,wherein an upper surface of the container body is provided with a tapered chimney. 8. The spent nuclear fuel assembly storage container according to claim 5,wherein the container body is made of heavy-weight concrete having a specific gravity of 3.5 or more. 9. A spent nuclear fuel assembly storage container comprising:a metal cask which stores a spent nuclear fuel assembly; anda container body which stores the metal cask and has a substantially hexagonal tubular shape,wherein the container body is made of neutron shielding concrete including an aggregate mainly including colemanite and/or hilgardite collected from an ore of an evaporation type sedimentary deposit and a cement which is a consolidating material and is manufactured by mixing the cement with the colemanite and/or hilgardite as an aggregate excluding ulexite and sassolite contained in the ore of the evaporation type sedimentary deposit. 10. An assembly of spent nuclear fuel assembly storage containers in which spent nuclear fuel assembly storage containers each including a metal cask storing a spent nuclear fuel assembly and a container body storing the metal cask and having a substantially hexagonal tubular outer surface are arranged,wherein the container bodies are arranged to have a honeycomb structure while the outer surfaces are brought into contact with each other, andwherein a space without the spent nuclear fuel assembly storage container is provided in such a manner that at least one outer surface of the bodies contacts external air. 11. An assembly of spent nuclear fuel assembly storage containers in which spent nuclear fuel assembly storage containers each including a metal cask storing a spent nuclear fuel assembly and a container body storing the metal cask and having a substantially hexagonal tubular outer surface are arranged,wherein the container bodies are arranged to have a honeycomb structure while the outer surfaces are brought into contact with each other, andwherein container bodies not storing the metal casks are arranged at a further outside of spent nuclear fuel assembly storage containers arranged at an outside of the spent nuclear fuel assembly storage containers.
051568187	abstract	Hazardous radioactive waste is compacted and cast into safely handled monolithic castings having a radiation barrier wall completely enclosing the radioactive waste by centrifugal casting processes in which the barrier wall may be either a pre-formed shell transported to the jobsite or it may be formed by biaxial centrifugal casting and curing of the barrier wall in a mold. When a pre-formed shell is used, means are provided for thickening the radiation barrier if necessary by biaxial casting of additional barrier material inside of the shell. Castable radioactive material is cast inside the barrier wall before removal of the casting mold from the finished cast monolith. The cast monolith is supported for rotation as the mold is removed therefrom so that additional impact resisting and radiation barrier material can also easily be applied to the exterior surface monolith if radiation leakage exceeds tolerance levels.
044629583	claims	1. A fuel assembly arrangement for use with a liquid metal fast breeder reactor, said fuel assembly arrangement being operable to reduce the tendency to form blockages in the upper portions of said fuel assembly in a hypothetical core disruptive accident, said fuel assembly arrangement comprising: an array of elongated fuel rods retained in parallel and vertical orientation, spacer means between said fuel rods for maintaining therebetween a closely spaced relationship, a vertically disposed duct member surrounding said fuel rods and forming a confined path for liquid metal coolant flow upwardly through said duct member and between said closely spaced fuel rods; said elongated fuel rods being of a first design and a second different design, each of said fuel rod designs including an elongated surrounding cladding member having fertile material formed as lower blanket pellets disposed at a lower portion of said cladding member, and fissile fuel formed as pellets positioned above said lower blanket pellets; the first of said fuel rod designs having a relatively short fission gas plenum positioned above said fission fuel pellets, upper blanket pellets positioned above said short fission gas plenum, an elongated fission gas plenum positioned above said upper blanket pellets, and means for retaining said upper blanket pellets and said fission fuel pellets in position within said elongated cladding; the second of said fuel rod designs having a relatively long fission gas plenum positioned above said fission fuel pellets, upper blanket pellets positioned above said elongated fission gas plenum, and a relatively short fission gas plenum positioned above said upper blanket pellets, and means for retaining said upper blanket pellets and said fission fuel pellets in position within said elongated cladding; the positioning of said upper blanket pellets in said first fuel rod design and the positioning of said upper blanket pellets in said second fuel rod design bearing such relationship that all portions of said upper blanket pellets in said first fuel rod design are positioned substantially beneath all portions of said upper blanket pellets in said second fuel rod design; and said fuel rods as retained in said duct being arranged so that fuel rods of said second design are positioned about the central portion of said duct, and said fuel rods of said first design are positioned peripherally about said fuel rods of said second design; whereby a hypothetical core disruptive accident which results in blockage proximate said upper blanket portions of said fuel rods of said second design will cause coolant metal to flow through the upper portion of said surrounding fuel rods of said first design. 2. The fuel assembly as specified in claim 1, wherein said spacer means between said fuel rods comprises wire wrapped about each of said rods. 3. The fuel assembly as specified in claim 1, wherein said means for retaining said upper blanket pellets and said fission fuel pellets in position within said elongated cladding comprises an internal ledge having a disc supported thereon and positioned immediately beneath said upper blanket pellets, and said upper blanket pellets and said fission fuel pellets are retained in position by spring means.
	claims	1. A charged particle beam device for inspecting a specimen, comprisinga charged particle beam source adapted to generate a primary charged particle beam;an objective lens device adapted to direct the primary charged particle beam onto the specimen;a retarding field device adapted to accelerate secondary charged particles starting from the specimen, wherein a first group of the secondary charged particles comprises secondary charged particles starting from the specimen with high starting angles, and a second group of the secondary charged particles comprises secondary charged particles starting from the specimen with low starting angles;a first detector device, comprisingat least two detector segments for detecting secondary particles, wherein the first detector device is configured to detect the second group of secondary charged particles, and wherein the first detector device has an opening for letting pass the first group of secondary charged particles or an opening configured for having at least one second detector device provided in the opening;wherein the objective lens device is adapted such that particles with different starting angles from the specimen exhibit crossovers at substantially the same distance from the specimen, forming a common crossover, anda first aperture located between the objective lens and the detector, having an opening with a diameter equal to or smaller than the central opening in the detector device, and which is provided in a position which fulfills at least one of the following properties:(i) it is in the vicinity of the common crossover,(ii) it is at a position where stray particles exhibit a maximum spread. 2. The device of claim 1, further comprising a second aperture. 3. The device of claim 2, wherein the second aperture is located at a position fulfilling at least one of the properties (i) or (ii). 4. The device of claim 1, further comprising at least one of:a secondary charged particle beam deflection device, a transfer lens device, a transfer lens device in combination with a secondary charged particle beam deflection device, and a beam separation device, adapted to separate the primary particle beam from at least one of the first and the second group of secondary charged particles. 5. The device of claim 1, wherein the charged particle beam source is adapted to generate the primary charged particle beam along a first optical axis, the charged particle beam device further comprising a beam separation device adapted to separate the primary particle beam from at least one group of the first and the second group of secondary charged particles, a transfer lens device positioned adjacent to the beam separation device and adapted to direct the at least one of the first and the second group of secondary charged particles in a direction along a second optical axis, and wherein the at least one second detector device is positioned along the second optical axis. 6. The device of claim 5, wherein the first detector device is positioned along the second optical axis, and wherein the second detector device (150) is provided in the center of first detector device. 7. The device of claim 1, further comprising means for adjusting the position of the secondary particle beam common crossover with respect to the first or second optical axis. 8. A method of inspecting a specimen with a charged particle beam device, comprisinggenerating a primary charged particle beam on a first optical axis;focusing the primary charged particle beam onto the specimen using an objective lens device;generating a secondary charged particle beam by the primary charged particle beam at the specimen, the secondary charged particle beam comprising a first group of secondary charged particles starting from the specimen with high starting angles and a second group of secondary charged particles starting from the specimen with low starting angles;focusing the secondary charged particle beam, such that particles from the first group and from the second group exhibit crossovers in substantially the same distance from the specimen, forming a common crossover;blocking stray particles with a first aperture disposed between the objective lens and the detector; and,detecting particles of the secondary charged particle beam, wherein the detecting comprises at least:detecting the second group of secondary charged particles with a first detector, wherein the first detector device has an opening for letting pass the first group of secondary charged particles or an opening configured for having at least one second detector device provided in the opening. 9. The method of claim 8, further comprising:adjusting a position of the common crossover of the secondary particle beam in a direction of the optical axis. 10. The method of claim 8, further comprising:adjusting the alignment of the secondary particle beam with respect to the first aperture and a detector in order to optimize a contrast detected by detector. 11. The method of claim 8, wherein the primary charged particle beam is generated along a first optical axis, the primary particle beam is separated from the secondary charged particles, and the secondary charged particles are directed in a direction along a second optical axis, and the secondary charged particles are detected along the second optical axis. 12. The method of claim 8, wherein secondary charged particles of the first group have starting angles to the specimen above 45 degrees, and secondary charged particles of the second group have starting angles to the specimen from 0 degrees to 45 degrees. 13. The method of claim 8, wherein a distance between the first aperture and the common crossover of secondary charged particles with different starting angles is smaller than 2 cm. 14. The method of claim 8, wherein the aperture is located in the vicinity of the common crossover of the secondary particles. 15. The method of claim 8, wherein the objective lens device comprises at least one element of the group consisting of a retarding field lens, a focusing lens, a magnetic lens, an electrostatic lens, and an electrostatic-magnetic lens.
	claims	1. A method for immobilization of a radioactive waste stream containing tetraphenyl borate compounds comprising the steps of:maintaining the pH of said waste stream in excess of pH 10;adding sodium hydroxide and/or potassium hydroxide to said waste stream;adding dissolving silica to said waste stream;adding a binder to said waste stream;adding an enhancer to said waste stream; andimmobilizing said waste stream without the process temperature exceeding 40° C. 2. The method of claim 1 including the step of maintaining the pH of said waste stream in excess of pH 10 by acid hydrolysis. 3. The method of claim 1 including the step of maintaining the pH of said waste stream between pH 12 and pH 14. 4. The method of claim 3 including the step of maintaining the pH of said waste stream between pH 12 and pH 14 by acid hydrolysis. 5. The method of claim 1 including the step of cooling said sodium hydroxide and/or potassium hydroxide to a temperature lower than said waste stream prior to adding said sodium hydroxide and/or potassium hydroxide to said waste stream. 6. The method of claim 1 including the step of cooling said sodium hydroxide and/or potassium hydroxide to a temperature lower than 40° C. prior to adding said sodium hydroxide and/or potassium hydroxide to said waste stream. 7. The method of claim 1 including the step of providing a radioactive waste stream containing a tetraphenyl borate compound. 8. The method of claim 1 wherein said dissolving silica is selected from the group consisting of fumed silica or fly ash. 9. The method of claim 1 including the step of adding fumed silica to said sodium hydroxide and/or potassium hydroxide prior to adding said sodium hydroxide and/or potassium hydroxide to said waste stream. 10. The method of claim 1 wherein said binder is selected from the group consisting of metakaolin, ground blast furnace slag, fly ash, and copper smelter slag. 11. The method of claim 10 wherein said ground blast furnace slag contains between 0.1 and 9 percent sulfides. 12. The method of claim 10 wherein said ground blast furnace slag is alkali-activated. 13. The method of claim 1 including the step of mixing said binder with said sodium hydroxide and/or potassium hydroxide and said enhancer prior to adding said sodium hydroxide and/or potassium hydroxide, binder, and enhancer to said radioactive waste stream. 14. The method of claim 1 wherein said enhancer is selected from the group consisting of soluble salt of metal, green rust, layered double hydroxide, layered bismuth hydroxide, mesoporous MPOx where M is selected from the group consisting of Ti, Al and Zr, mesoporous silica, ziolitic material, porous glass ion. 15. The method of claim 14 where said soluble salt of metal is selected from the group consisting of Ag, Cv, Ag2S, Cu2S and FeS. 16. The method of claim 14 where said green rust is selected from the group consisting of Fe2+ and —Fe3+. 17. The method of claim 14 where said layered double hydroxide is activated by calcination. 18. The method of claim 14 where said layered bismuth hydroxide is BiPbO2NO3. 19. The method of claim 14 where said mesoporous silica is doped from the group consisting of P, Zr and Al. 20. The method of claim 14 where said zeolitic material is impregnated with silver. 21. The method of claim 1 wherein said enhancer is added to said waste stream prior to adding said sodium hydroxide and/or potassium hydroxide and said binder. 22. The method of claim 1 including the step of performing microbial mediation on said waste stream to reduce nitrate to nitrogen prior to adding said sodium hydroxide and/or potassium hydroxide, said binder and said enhancer. 23. The method of claim 22 including the step of diluting said waste stream prior to performing microbial mediation. 24. The method of claim 23 including the step of evaporating said waste stream to reconcentrate said waste stream. 25. The method of claim 22 including the step of adjusting the pH of the waste stream to allow for microbial mediation. 26. The method of claim 22 wherein said microbial mediation occurs using halophylic bacteria. 27. A method for immobilization of a radioactive waste stream containing tetraphenyl borate compounds comprising the steps of:maintaining the pH of said waste stream in excess of pH 10;adding sodium hydroxide and/or potassium hydroxide to said waste stream;adding dissolving silica to said waste stream;adding a binder to said waste stream;adding an enhancer to said waste stream that immobilizes one or more heavy metals and/or radionuclides in the waste stream by precipitation, absorption, and/or ion exchange mechanisms; andimmobilizing said waste stream without the process temperature exceeding 40° C. 28. The method of claim 27 including the step of maintaining the pH of said waste stream in excess of pH 10 by acid hydrolysis. 29. The method of claim 27 including the step of maintaining the pH of said waste stream between pH 12 and pH 14. 30. The method of claim 27 including the step of maintaining the pH of said waste stream between pH 12 and pH 14 by acid hydrolysis. 31. The method of claim 27 including the step of cooling said sodium hydroxide and/or potassium hydroxide to a temperature lower than said waste stream prior to adding said sodium hydroxide and/or potassium hydroxide to said waste stream. 32. The method of claim 27 including the step of cooling said sodium hydroxide and/or potassium hydroxide to a temperature lower than 40° C. prior to adding said sodium hydroxide and/or potassium hydroxide to said waste stream. 33. The method of claim 27 including the step of providing a radioactive waste stream having a tetraphenyl borate compound. 34. The method of claim 27 wherein said dissolving silica is selected from the group consisting of fumed silica and fly ash. 35. The method of claim 27 including the step of adding fumed silica to said sodium hydroxide and/or potassium hydroxide prior to adding said sodium hydroxide and/or potassium hydroxide to said waste stream. 36. The method of claim 27 wherein said binder is selected from the group consisting of metakaolin, ground blast furnace slag, fly ash, and copper smelter slag. 37. The method of claim 27 wherein said ground blast furnace slag contains between 0.1 and 9 percent sulfides. 38. The method of claim 27 wherein said ground blast furnace slag is alkali-activated. 39. The method of claim 27 including the step of mixing said binder with said sodium hydroxide and/or potassium hydroxide and said enhancer prior to adding said sodium hydroxide and/or potassium hydroxide, binder, and enhancer to said radioactive waste stream. 40. The method of claim 27 wherein said enhancer is selected from the group consisting of soluble salt of metal, green rust, layered double hydroxide, layered bismuth hydroxide, mesoporous MPOx, where M is from the group Ti, Al and Zr, mesoporous silica, zeolitic material, porous glass ion. 41. The method of claim 40 where said soluble salt of metal is selected from the group consisting of Ag, Cv, Ag2S, Cu2S and FeS. 42. The method of claim 40 where said green rust is selected from the group consisting of Fe2+ and —Fe3+. 43. The method of claim 40 where said layered double hydroxide is activated by calcinations. 44. The method of claim 40 where said layered bismuth hydroxide is BiPbO2NO3. 45. The method of claim 40 where said mesoporous silica is doped from the group consisting of P, Zr and Al. 46. The method of claim 40 where said zeolitic material is impregnated with silver. 47. The method of claim 27 wherein said enhancer is added to said waste stream prior to adding said sodium hydroxide and said binder. 48. The method of claim 27 including the step of performing microbial mediation on said waste stream to reduce nitrate to nitrogen prior to adding said sodium hydroxide, said binder and said enhancer. 49. The method of claim 48 including the step of diluting said waste stream prior to performing microbial mediation. 50. The method of claim 48 including the step of evaporating said waste stream to reconcentrate said waste stream. 51. The method of claim 48 including the step of adjusting the pH of the waste stream to allow for microbial mediation. 52. The method of claim 48 wherein said microbial mediation occurs using halophylic bacteria.
	abstract	A reactor vessel that performs work inside a nozzle stub of the reactor vessel, including a platform unit that is provided at an upper portion inside the reactor vessel and includes a substantially cylindrical side wall portion and a bottom portion blocking the lower end of the side wall portion; an access window that is provided at the side wall portion of the platform unit an access window moving device that opens and closes the access window; a working device; and a control device that is provided at the outside of the reactor vessel and controls the access window moving device and the working device, wherein the control device drives the access window moving device to open the access window, drives the working device to perform work inside the nozzle stub, and then drives the access window moving device to close the access window after the performance of the work.
	abstract	A nuclear reactor includes an internal steam generator and a nuclear core disposed in a containment structure. A condenser is disposed outside the containment structure, and includes a condenser inlet line tapping off a steam line connected to the steam generator outside the containment structure, and a condensate injection line conveying condensate from the condenser to the integral steam generator. Isolation valves are located outside the containment structure on a feedwater line, the steam line, and the condensate injection line. The valves have an operating configuration in which the isolation valves on the feedwater and steam lines are open and the isolation valve on the condensate injection line is closed, and a heat removal configuration in which the isolation valves on the feedwater and steam lines are closed and the isolation valve on the condensate injection line is open.
	summary
052451950	summary	BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the technical field of X-ray shielding, and particularly to the protection of humans, such as X-ray technicians and equipment operators, from the effects of exposure to radiation damage. 2. Background of the Invention Medical workers and others who work with X-rays and X-ray equipment require protection from the radiation. Long term exposure, even to very low levels of X-rays, is known to produce a substantial number of serious effects. Such workers are normally furnished with protective garments, including coats, aprons, gloves, thyroid shields, gonad shields, and the like. Protective garments or coverings are increasingly being employed to protect medical patients from excessive and stray X-ray exposure. Protective garments may be in the same form as those employed by technicians. Other protective coverings may include sheets, drapes, Such protective garments are made most commonly from rubber sheets filled with lead, lead oxide, or other lead salts, or from laminates of lead foil faced with polymer films. Natural rubber is frequently employed, but other synthetic rubber may also be employed, such as styrene-butadiene (SBR), polyisoprene, polybutadiene, and the like, as well as polyolefins, such as polyethylene, or polyesters, such as polyethylene terephthalate are employed as well. So that the relative protective value of shielding materials can be assessed and compared, it is common to relate the attenuation of incident X-rays to the attenuation of elemental lead foil. Standard levels of protection for X-ray shielding are 0.5 mm of lead and 0.25 mm of lead, and equivalents to these attenuation valves or better must be attained in other forms of materials. Thus, attenuation is normally expressed as mm of lead equivalence. The forms of shielding materials heretofore employed are quite heavy, resulting in cumbersome, hot, uncomfortable, and inconvenient garments and the like which often hinder the wearer. In addition, the materials are not durable because of the very high loadings of the filler materials into the rubber sheet or the eventual breakdown of lead foils, after repeated flexing. In addition, the materials are relatively difficult to fabricate into useful garment forms. Barium salts, and particularly barium sulfate, are extensively used as a contrast medium for diagnostic X-rays and have long been known to be opaque to such radiation. Such salts have been incorporated into surgical materials such as sponges, sutures, and the like for post-operative detection. See, for example, U.S. Pat. No. 4,185,626. Barium sulfate is also employed as a base material for X-ray fluorescent recording film. Barium salts, and barium sulfate in particular, have not been employed in X-ray shielding films because the volume required to achieve acceptable levels of shielding require either unacceptably thick and expensive sheets or loadings in rubber films at proportions which unacceptably compromise the mechanical properties, and particularly the flexural modulus and resistance to flexing. While barium and barium salts have often been incorporated into polymer systems for a wide variety of purposes, the levels acceptable rarely exceed about 40 weight percent, although occasional applications at levels up to about 50 percent are known. Higher loadings are required to afford useful X-ray shielding in sheet materials of workable thicknesses. SUMMARY OF THE INVENTION It is an object of the present invention to provide X-ray protective films and X-ray protective garments and the like comprising thermoplastic elastomers and a barium salt in an amount sufficient to provide effective X-ray shielding, where the film is pliable, durable, relatively light in weight, and suitable for fabrication into coats, jackets, aprons, gowns, gloves, thyroid shields, gonad shields, patient protective wear and drapes, film bags, carriers, shipping containers, and the like. The protective sheet or film will ordinarily comprise an elastomer of a synthetic thermoplastic polymer or blend of polymers filled with finely divided particulate barium sulfate. The barium sulfate will be present at levels of from about 60 to about 90 weight percent. Preferably the barium sulfate is treated with a coupling agent, such as an organo silane or organic titanium salts and the like.
050892100	description	Referring to FIG. 1 a reactor R is illustrated having a vessel V, the vessel V having the purpose of containing a nuclear reaction under pressure. A core K of fuel bundles is illustrated. Fuel bundle K includes an underlying group of control rods C which control rods C force cruciformed shaped control rods into and out of the interstices between adjacent fuel bundles (see FIG. 2). The reactor R includes a jet pump J for inducing coolant flow. Specifically, jet pump J induces coolant flow down and into the underlying group of control rods C. Fluid flows upwardly through the core K through a top guide T returning to the top of the reactor. Downward flow is induced by the jet pump J over a shroud SH between the side walls of the vessel V and the core K. Thus a downward fluid flow occurs on the outside and an upward fluid flow on the inside. Produced saturated steam is extracted from the top of the reactor through steam separator S and dryer D. This saturated steam permits the extraction of power through turbines and generators (not shown). Typically the turbines exhaust to a condenser where the spent steam is condensed and made up into reactor feed water for continuous recycling of the coolant. Referring to FIG. 2, the reactor at four side by side fuel bundles is illustrated. A lower core plate 24 forms a barrier. This barrier is horizontal and disposed between the group of control rods C (see FIG. 1; not shown FIG. 2) contained below the fuel bundles and the discrete overlying fuel bundles themselves. Barrier 24 enables water to be forced through the bottom of the fuel bundles into and within the channel around the discrete fuel rods. Each fuel bundle includes a lower tie plate T1 (see FIG. 3). At the upper end, each fuel bundle includes an upper tie plate T2. Extending between the tie plates there is defined a channel 30. It is the function of the channel 30 to confine fluid flow between the tie plates and within the channel so that water moderator can form two discrete functions. First, the water moderator takes the fast high energy neutrons emitted in the fission reaction and causes the neutron to become slow or thermal neutrons. It is the slow or thermal neutrons which cause the continuing nuclear reaction to occur. Second, the upwardly flowing water is turned in part to steam. This steam is used to extract work from the heat of the nuclear reaction by conventional turbine condensers and recycling to the nuclear reactor shown in FIG. 1. Referring further to FIG. 2, a control rod 40 is illustrated. The control rod 40 passes between four fuel bundles. These fuel bundles being denominated 31, 32, 33 and 34. Some attention can now be given to the disposition of the fuel bundles. Typically, and at their lower end, the fuel bundles are each supported on a fuel support casting 50. Fuel support casting 50 extends downwardly into and through holes 26 in the top guide 24. Fuel support casting finds support on the top of the control rod drive housing (not designated). The control rod drive housing in turns passes the weight of the fuel bundles to the bottom of the reactor vessel V (see FIG. 1). The discrete fuel bundles 31-34 are supported at their upper end at a top guide G. Top guide G includes a metallic lattice including cross members 61, 62, 63, and 64. These respective cross members support the fuel bundles 31-34 in vertical upstanding relation. The fuel bundles are spaced apart. This spacing apart forms a cruciform sectioned interstices 70 illustrated between the discrete fuel bundles. This cruciform sectioned interstices 70 has control rod 40 shown placed therein. Control rod 40 is conventional. It typically is inserted through an aperture 26 in core plate 24 from a position of residence in the control rod drive housing (not shown). In controlling the nuclear reactor, the control rod passes upwardly between the respective fuel bundles. Its cruciform section includes a number of flat planar surfaces, 41, 42, 43 and 44. It can be seen that flat planar surface 41 passes in the interstitial area between fuel bundles 33, 34. Planar surface 42 passes between bundles 31, 34. Planar surface 44 passes between bundles 31, 32 and finally planar surfaces 43 passes between bundles 33 and 32. Typically there is only provided one control rod for each group of four fuel bundles. It will further be understood that two flow paths for water are generically present. A first flow path for water is within the channels of the fuel bundles between the tie plates T1 and T2. A second flow path for water is in the so-called core bypass region. This is the region between adjacent fuel bundles. During normal operation of the reactor, the flow path between the tie plates and within the fuel bundle contains steam. This steam is present in higher fractions as the water rises from the bottom of the fuel bundle to the top of the fuel bundle. During start up operation of the reactor, the flow path between the tie plates and within the fuel bundle contains water. This water causes higher neutron moderation. This high neutron moderation requires the establishment of the cold reactivity shut down zone. During all normal operations the core by-pass region is flooded with water. This core by-pass region exerts on those fuel rods adjacent to it a high degree of neutron moderation. Accordingly, higher levels of thermal neutron flux are present in this region. Referring to FIG. 4A a fuel bundle, B1 of the type herein used is illustrated. General observations can be made. First, the bundle includes a rectangular section channel 60 and a central water rod W. Water rod W and the exterior of channel 60 commonly contain water without steam intermixed. Accordingly, these areas of the fuel bundle produce relatively high levels of moderation. Secondly, it can be seen that the respective corners of the fuel bundle 61, 62 and 63 are the locations for the gadolinium containing rods having the burnable absorber gadolinium. Corner 64 is typically adjacent instrument tubing such as that tubing utilized for local power range monitors. Since gadolinium will have an adverse effect on the neutron flux, a quantity measured by the instrument tubing, it is omitted from the bundle corner 64. Typically, the control rod 40 illustrated in FIG. 2 passes with its cruciform shaped intersection adjacent corner 63 of bundle B1. The reader will realize that in the normal operating state of the reactor, the control rod is typically fully withdrawn. As will hereinafter be set forth, the particular design herein disclosed is utilized with a so-called D lattice nuclear reactor. In such a D lattice nuclear reactor, the fuel bundle spacing varies. Typically, and at corner 64, the fuel bundles are relatively closely spaced. Opposite corner 64 and at corner 63, the fuel bundles defined their widest separation. It is into the interstices between the fuel bundle at corner 63 that the control rod 40 shown in FIG. 2 passes. At corner 61, 62 spacing of the fuel bundles apart from one another is intermediate those spacing encountered at corners 63, 64. Remembering that the control rod 40 is normally fully withdrawn, and remembering that the spacial gap adjacent corner 63 is the largest, it can be seen that five rods containing gadolinium and labelled G1 and G3 and G4 are located adjacent corner 63. As distinguished from corner 63, corner 62, 61 includes only three gadolinium rods. These rods being labelled G2, G3 and G4. Finally, corner 64 is without gadolinium. It will further be observed that water rod W occupies approximately 4 lattice position in the 8.times.8 lattice. Accordingly, 49 of the remaining rods have combinations of plutonium mixed with the depleted uranium. Referring to FIG. 4B, the concentrations of plutonium can readily be understood. Fuel rods 5 include plutonium at the level of 5 weight percent. Fuel rods 9 include plutonium at the level of 9 weight percent. Finally, fuel rods 12 include plutonium at 12 weight percent. It will further be seen that 33 of the disclosed rods have plutonium at the level 12 weight percent. It can be seen that at this level, the disclosed bundle design has a relatively high concentration of plutonium. Further, all of the so-called MOx bundle of fuel rods (that is rods 5, 9 and 12) have a depleted uranium enrichment. Specifically, these rods include two-tenths of a weight percent of uranium -235. Preferably, the material is taken from any source of depleted uranium such as enrichment plant tails and the like. It can further be seen that gadolinium is contained in four rod types. In two of these rod types, G1 and G2, the gadolinium is evenly distributed throughout the rod length. This being the case, these particular rods do not contribute significantly to the formation of the cold reactivity shutdown zone. Referring to rods G3 and G4, it can be seen that gadolinium in high weight percents (four weight percent in rod G3 and five weight percent in rod G5) is distributed with large percentiles being within the so-called cold reactivity shutdown zone. The enrichment levels of rod G1 is approximately two weight percent. The enrichment level of rod G2 is 3.95 weight percent. Finally, rod G3 includes 3 weight percent uranium with rod G4 including 3.95 percent uranium -235. Small vertical sections of natural uranium are distributed in the bottom and top 6" of the fuel rods. Referring to FIG. 4C, a bundle average vertical axial profile is set forth. In the vertical axial profile, the shutdown zone of the disclosed bundle is illustrated. The reader will remember that this shutdown zone is imparted solely by the gadolinium rods G3 and G4. Further, the reader will understand that the varying concentrations of plutonium are held to a mere 3 concentrations. Furthermore, the heaviest concentration of plutonium predominates the bundle. It will be understood that practical manufacturing dictates that the gadolinium rods usually be fabricated in a facility separate and apart from those rods including large amounts of plutonium. It can be seen that the disclosed invention only includes 11 gadolinium rods and that these gadolinium rods can be conveniently assembled elsewhere and shipped in the site of fuel bundle assembly. We have here shown in the preferred embodiment a fuel bundle whose initial reactivity profile has been tailored to define a so-called "cold reactivity shut down zone". The reader will appreciate that this is the preferred embodiment. It will be understood that this invention may be practiced on a less than preferred basis by the location of gadolinium rods at the corner locations without tailoring of the cold reactivity profile to create the "cold reactivity shut down zones". Having set forth, the physical construction of a fuel bundle, two graphic illustrations can further show the advantage of this fuel design. Referring to FIG. 5A, it can be seen that the plot of an ordinary fuel bundle against the improved bundle of this disclosure illustrates improved reactivity. Specifically by plotting infinite reactivity against exposure in gigawatt days per short ton it can be seen that virtually at all times during the life of the fuel bundle that the reactivity remains higher. Specifically, and remembering that the bundles of this design will be distributed throughout the core, it can be seen that the improved reactivity will be imparted to the remainder of the core. This being the case, less enrichment over all of the core will be required. Referring to FIG. 5B, the reader will understand that the physics of the plutonium combinations herein utilized will inevitably cause higher peaking. Peaking is that phenomena of local heating which local heating limits the overall power of a fuel bundle to avoid local damage to any part of a nuclear fuel rod within the fuel bundle. It has been found however, that the peaking with exposure although higher does not significantly exceed the peaking at the beginning and end of a typical fuel bundle cycle. This being the case, an acceptable compromise of this parameter occurs. Having set forth the construction of a fuel bundle on an 8.times.8 array, referring to FIG. 6A, 6B and 6C, the construction of a fuel bundle on a 9.times.9 array is illustrated. Referring to FIG. 6A, a fuel bundle B2 including first and second water rods, W1 and W2 is illustrated. These respective water rods displace seven lattice positions leaving 84 positions to be filled. So-called partial length rods are utilized in this invention. Specifically, these partial length rods denominated P5 and P12 extend 5/8 the full height of the fuel bundle. That is to say assuming that the fuel rods include 11' 8" of nuclear fuel, partial length rods extend 8'6" from the bottom of the fuel rod to and towards the top. These partial length rods include respectively 5% plutonium for rods P5 and 12% plutonium for rods P12. Both include a mixture of uranium 235 in the range of 0.2 weight percent. It can also be seen that each of the partial length rods is located in the second row removed from the channel wall of the bundle B2 has been found that such a location of the partial length rods imparts maximum advantage to the design herein disclosed. The cold reactivity shutdown zone (see FIG. 6C) is imparted solely by the axial distribution of rods G3 and the 3 weight percent of gadolinium there specified. Specifically, such rods have a uniform 3% uranium enrichment. Within the shutdown zone, (see FIG. 6C) gadolinium in the amount of 3 weight percent is utilized. It can be seen that there is one rod G3 in the respective fuel bundle corners 61, 62 and 63. A weighted gadolinium rod has been eliminated from fuel bundle corner 64. This is because fuel bundle corner 64 is typically immediately adjacent instrumentation such as the local power range monitor. Adjacent the corners, there can be seen a second gadolinium rod G2. Gadolinium rod G2 has two weight percent gadolinium distributed only to the shut down zone. Finally, and again near the corners a uranium rod U1 without any plutonium intermixed is specified. These uranium rods are again adjacent the corner lattice position. It thus can be seen that the disclosed fuel design includes only three classes of gadolinium rods and one conventional uranium rod containing 3.6 weight percent uranium. The remaining rods all contain plutonium. Specifically, rod P5 includes 5.0 weight percent plutonium. Rod P9 contains 9.0 weight percent plutonium, rod P12 includes 12 weight percent plutonium. These respective weight percents of plutonium are intermixed with depleted uranium sources on the order of 2/10ths of a percent. Referring to FIG. 6C, the bundle average vertical profile of the fuel bundle can be seen. In the case of the preferred embodiment here illustrated, gadolinium has been tailored in its vertical profile to create the so-called "cold reactivity shut down zones". As hereinbefore set forth, embodiments without these cold reactivity shut down zones, while not preferred, are within the scope of this invention. In the following claims, the term "adjacent the corners" will be used. The reader will understand by using this term we intend to include the corner location, the two rods adjacent the corner, these latter two rods being adjacent the channel. Thus, this definition can include twelve lattice positions within a fuel bundle.
	summary
043705553	claims	1. A photon storing and irradiation device having a radiation shielded body comprising a cylindrical container of circular cross section, having an axis (A), in said body; a disk housing located in said cylindrical container, dimensioned slightly smaller than that of said cylindrical container; a cylindrical gamma radiation containing housing in said disk, said housing having an opening on the periphery of the disk, with an axis perpendicular to axis (A) when the disk is rotated inside said body; said disk also containing a passage having an opening at one and the other of its ends at the periphery of the disk and capable of being located simultaneously opposite an optical device and a precollimator located in the walls of said cylindrical container and connected by an optical fiber, the ends of which, respectively called the receiver and emitter are located at right angles to each end of said passage via dismountable fixing means, and also having an optical device adjacent said body capable of producing a ray of light onto the receiver of said fiber; means for rotating said disk between a first position enabling said housing to irradiate a desired object for which the axis of said housing axis coincides with the axis (Y,Y) of the precollimator, and a second position for which said irradiation source is in a stored position while enabling the optical device by means of the optical fiber to produce a ray of light at the precollimator; and a part having an axis (Y,Y) perpendicular to axis (A) in the bottom of said body with said precollimator disposed at right angles to said port of axis (Y,Y). 2. The device of claim 1, wherein the axis of the receiver and emitter ends of the optical fiber define an angle close to 90.degree.. 3. The device of claim 1, comprising electrical means for locking the disk in said first position. 4. The device of claim 1, wherein the disk is made of sintered tungsten. 5. The device of claim 1, wherein the body is constituted by a mass of lead in which is included a block of depleted uranium, this block defining the portion of the wall of the cavity located around said source when said disk is in said second position. 6. The device of claim 1, wherein the container of the irradiation head comprising the precollimator is provided with flanges for temporarily fixing it, by means of screws, on the movable arm of the support. 7. The device of claim 1, comprising mechanical means for automatically placing the disk in said first position. 8. The device of claim 7, wherein means for displacing said disk comprise a shaft coupled, on the one hand, to a geardown motor via an electromagnetic clutch and, on the other hand, to a rack movable between two end positions corresponding respectively to said first and second positions of the disk. 9. The device of claim 8, wherein the end position of the rack corresponding to said second position of the disk is defined by an electromagnetic stop adapted to lock the rack, this stop acting against a spring adapted to return the rack into an end position defined by a mechanical stop.
	abstract	This scintillator plate 1 is a scintillator plate which is a member of a flat plate shape to emit scintillation light according to incidence of radiation transmitted by an object A and which is used in an image acquisition device to condense and image the scintillation light, the scintillator plate comprising: a partition plate 2 of a planar shape which transmits radiation; a scintillator 3 of a flat plate shape which is arranged on one surface 2a of the partition plate 2 and which converts the radiation into scintillation light; and a scintillator 4 of a flat plate shape which is arranged on the other surface 2b of the partition plate 2 and which converts the radiation into scintillation light.
	abstract	A method of manufacturing a collimator including providing a plate-like body, coating a predetermined portion of a surface of the body with an x-ray absorbing material, and machining at least one collimating slit through the coating and the plate-like body. According to one exemplary embodiment, the coating is applied through a thermal spray process. According to another exemplary embodiment, wire electrical discharge machining (EDM) is used to machine the collimating slits. A collimator manufactured in accordance with the presently disclosed method produces precise energy beam cross-sections, yet is less expensive to manufacture.
063079135	claims	1. An imaging system comprising: a plasma source providing a shaped radiation field, wherein said plasma source comprises a laser source providing an output laser beam, shaping optics converting the light from the light source into a shaped output laser beam, the shaped output laser beam having a cross-sectional illumination field profile, and a target generating a shaped plasma discharge emitting said shaped radiation field, the shape of the radiation field determined in part by the shape of the illumination field of said shaped output laser beam; a condenser having optics shaped to efficiently transmit the shaped radiation field; a transmissive or reflective object having a pattern thereon positioned to receive the shaped radiation field from the condenser; a recording medium illuminated by the shaped radiation field; at least one additional laser source, each providing an additional output laser beam; and at least one additional shaping optics corresponding to each said additional laser source, each said additional shaping optics converting the output laser beam from its corresponding additional laser source into a corresponding additional shaped output laser beam having a cross-sectional illumination field profile. a plasma source providing a shaped radiation field, wherein said plasma source comprises a laser source providing an output laser beam, shaping optics converting the light from the light source into a shaped output laser beam, the shaped output laser beam having a cross-sectional illumination field profile, and a target generating a shaped plasma discharge emitting said shaped radiation field, the shape of the radiation field determined in part by the shape of the illumination field of said shaped output laser beam; a condenser having optics shaped to efficiently transmit the shaped radiation field; a transmissive or reflective object having a pattern thereon positioned to receive the shaped radiation field from the condenser; and a recording medium illuminated by the shaped radiation field; wherein the laser source includes: a plasma source providing a shaped radiation field, wherein said plasma source comprises a plasma generating target emitting said shaped radiation field, and a power source providing an electrical output to the target; a condenser having optics shaped to efficiently transmit the shaped radiation field; a transmissive or reflective object having a pattern thereon positioned to receive the shaped radiation field from the condenser; a recording medium illuminated by the shaped radiation field; and a delay mechanism, wherein said delay mechanism postpones the electrical output from said power source until after application of a laser beam. a power source providing an electrical output; a plurality of electrodes connected to said power source to receive and direct the electrical output; a target generating a shaped radiation field determined by current path of said electrical output, a condenser having optics shaped to efficiently receive the shaped radiation field; a photolithography mask having a pattern thereon positioned to receive the shaped radiation field from the condenser; a photoresist coated wafer illuminated by the shaped radiation field transmitted from the condenser. 2. An imaging system comprising 3. An imaging system comprising: 4. A photolithography system comprising:
	abstract	The subject of the present invention is principally a transportation device for nuclear fuel which includes a compartment (2) to receive a casing loaded with irradiated fuel, the said compartment (2) including an opening (4) for loading and unloading of the casing (18) from the device and an opening (6) for applying a longitudinal force on the casing (18) causing it to move inside the compartment (2) in the direction of the unloading opening in order to unload it, through a force transmission component (32) which forms a biological shield.
	claims	1. A method of decontaminating metal surfaces in a cooling system of a nuclear reactor, wherein the metal surfaces are coated with metal oxides including containing radioisotopes, and wherein the cooling system comprises one or more primary loops including at least one reactor coolant pump, and a residual heat removal system, the method comprises conducting a plurality of treatment cycles, with each of the treatment cycles comprising:a) an oxidation step wherein the metal oxides containing radioisotopes are contacted with an aqueous solution of a permanganate oxidant;b) a decontamination step wherein the metal oxides subjected to the oxidation step are contacted with an aqueous solution of an organic acid selected from the group consisting of oxalic acid, formic acid, citric acid, tartaric acid, picolinic acid, gluconic acid, glyoxylic acid and mixtures thereof, so as to dissolve at least part of the metal oxides and the radioisotopes; andc) a cleaning step wherein at least the radioisotopes are immobilized on an ion exchange resin;wherein the oxidation step comprises at least one acidic oxidation step and at least one alkaline oxidation step carried out one after another in either the same or different treatment cycles, and wherein the plurality of treatment cycles comprises at least one treatment cycle including a high temperature oxidation step, during which high temperature oxidation step the permanganate oxidant solution is kept at a temperature of at least 100° C. and wherein the at least one reactor coolant pump is used to circulate and heat the oxidation solution inside the one or more primary loops and the residual heat removal system is used to control the temperature of the oxidant solution during the high temperature oxidation step. 2. The method according to claim 1, wherein the permanganate oxidant is selected from the group consisting of HMnO4, HMnO4/HNO3, KMnO4/HNO3, KMnO4/KOH and KMnO4/NaOH. 3. The method according to claim 1, wherein the aqueous solution of the permanganate oxidant has a pH value of less than about 6 in the at least one acidic oxidation step. 4. The method according to claim 1, wherein the aqueous solution of the permanganate oxidant has a pH value of at least 8 in the at least one alkaline oxidation step. 5. The method according to claim 3, wherein the permanganate oxidant in acidic oxidation step comprises HMnO4, HMnO4/HNO3 or KMnO4/HNO3 or other metal salts of permanganate. 6. The method according to claim 4, wherein the permanganate oxidant in the alkaline oxidation step comprises KMnO4/NaOH or KMnO4/KOH. 7. The method according to claim 1 wherein the plurality of treatment cycles comprises an alternating sequence of treatments cycles wherein a first treatment cycle comprising an acidic oxidation step is followed by a second treatment cycle comprising an alkaline oxidation step, or vice versa. 8. The method according to claim 1 wherein all of the plurality of treatment cycles comprise a high temperature oxidation step wherein the oxidant solution is kept at a temperature of at least 100° C. 9. The method according to claim 1 wherein during the high temperature oxidation step the oxidant solution is kept at a temperature in a range of from 120 to 150° C. 10. The method according to claim 1 wherein at least one acidic oxidation step comprises a high temperature oxidation step wherein the oxidant solution is kept at a temperature of at least 100° C. 11. The method according to claim 1 wherein at least one alkaline oxidation step comprises a high temperature oxidation step wherein the oxidant solution is kept at a temperature of at least 100° C. 12. The method according to claim 1 wherein the organic acid is oxalic acid. 13. The method according to claim 1 wherein the oxidant solution is kept at a pressure of more than 1 bar during the high temperature oxidation step. 14. The method according to claim 3, wherein the aqueous solution of the permanganate oxidant has a pH value of less than about 4 in the at least one acidic oxidation step. 15. The method according to claim 4, wherein the aqueous solution of the permanganate oxidant has a pH value of at least 10 in the at least one alkaline oxidation step. 16. The method according to claim 8 wherein during each of the high temperature oxidation steps the oxidant solution is kept at a temperature in a range of from 120 to 150° C.
043127045	claims	1. A releasable shut-off device for a downward leading quick emptying conduit for bulk material in the form of solid particles having a predetermined minimum cross-sectional dimension, comprising: a pair of interfitting rod combs (14,18) mounted so as to be individually movable in and out of the conduit cross-section, and equipped with structural means for moving the rods of the comb in unison, said combs being constituted and disposed so as to form, complementarily, a load-carrying wall perpendicular to the axis of said conduit in the closed position of said combs, the gaps between the rods (13,17) of each individual comb (14,18) having in every case a width less than said minimum cross-sectional dimension of said particles; and means for individually actuating the rod-moving means of each of said combs (14,18), whereby the readiness of the device may be verified by moving each comb alone to its open position and back and whereby quick emptying of said container may be performed by moving both combs to their open positions. 2. A releasable shut-off device as defined in claim 1, in which the rods (13,17) of both combs (14,18) fit together to form a closed wall having grooves conforming in cross-section to the cross-section of said particles, which grooves run in the longitudinal direction of the rods, are provided on the upstream side of the shut-off device, and have their bottoms (15) in each case formed by the upstream sides of the rods (13) of a first one of said combs (14) and the flanks of which grooves are formed in each case by the two adjacent rods (17) of the second of said combs (18). 3. A releasable shut-off device as defined in claim 2, in which said rods (13) of said first comb (14) forming the groove bottoms (15) have a generally I-shaped cross-section (FIG. 3) and in which the respective widths of the rods (13,17) of said first comb (14) and of said second comb at the downstream side of said combs are substantially equal. 4. A releasable shut-off device as defined in claim 3, in which the rods (17) of said second comb (18) are hollow, and in which said rod-moving means of each comb include a cross-member outside said conduit, said cross-members of the respective combs being located on opposite sides of said conduit. 5. A releasable shut-off device as defined in claim 4, in which guide openings are provided in the conduit wall for the introduction of the rods of said second comb, in which device the ends of the rods (17) of said second comb (18) in the open position, as the result of different lengths and tapered ends, fill and close off said guide openings; in which device there is also provided a half-ring-shaped cover plate (28) connected to outer rods (27) of said second comb (18), said cover plate having slots (29) for the passage therethrough of the rods (13) of said first comb (14); and in which device the arrangement of rod ends and cover plate provides a largely closed duct wall half in the opposite wall region upon the opening of either of the combs of the shut-off device. 6. A releasable shut-off device as defined in claim 4, in which said first comb (14) is movable upwards out of its closed position and said second comb (18) is movable downwards into its open position. 7. A releasable shut-off device as defined in claim 4, in which the rods (13) of said first comb (14) are prolonged by small extension (26) and the opposite conduit wall is provided with corresponding cavities for receiving said extensions. 8. A releasable device as defined in any one of the preceding claims in which the rods (13,17) of comb combs (14,18) in the region of their external ends have extensions jutting at right angles out of the closure plane, which are affixed to connecting cross-members (20,21) of said rod combs (14,18), which cross-members are arranged to be driven parallel to said closure plane in a path spaced from said closure plane. 9. A releasable device as defined in any one of claims 1-7, in which each of said combs (14,18) is provided with a spindle drive (22,23) spaced to one side of the closure plane of said combs, each comb being provided with roller bearings and guide rails for guiding said combs (14,18) in the course of the closing and opening movements thereof. 10. A releasable device as defined in any one of claims 1-7, in which said shut-off device is enclosed by a double pressure container (31,32) enclosing the entire paired-comb closure system. 11. A releasable shut-off device as defined in claim 1 for a container which is a pebble bed nuclear reactor vessel in which the particles of bulk material for which the shut-off device provides quick-release capability are balls of reactor fuel which are of substantially uniform diameter. 12. A releasable shut-off device as defined in claim 11, in which the rods (13,17) of both combs (14,18) fit together to form a closed wall having grooves comforming in cross-section to the cross-section of said fuel balls, which grooves run in the longitudinal direction of the rods, are provided on the upstream side of the releasable shut-off device, and have their bottoms (15) in each case formed by the upstream sides of the rods (13) of the first of said combs (14) and the flanks of which grooves are formed in each case by the two adjacent rods (17) of the second of said combs (18). 13. A releasable shut-off device as defined in claim 12, in which said rods (13) of said first comb (14) forming the groove bottoms (15) have a generally I-shaped cross-section (FIG. 3) and in which the respective widths of the rods (13,17) of said first comb and of said second comb (18) at the downstream side of said combs are substantially equal. 14. A releasable shut-off device as defined in claim 13, in which the rods (17) of said second comb (18) are hollow. 15. A releasable shut-off device as defined in claim 14, in which the ends of the rods (17) of said second comb (18) has the result of different lengths and tapered ends, fill and close off in the open position the guide openings provided in the conduit wall for introduction of the rod, and there is also provided a half-ring-shaped cover plate (28) connected to the end rods (27) of said second comb (18), said cover plate having slots (29) for the passage therethrough of the rods (13) of said first comb (14), and in which device the arrangement of the rod ends (13) and cover plate provides a largely closed duct wall half in the opposite wall region upon the opening of either of the combs of the releasable shut-off device. 16. A releasable shut-off device as defined in claim 14, in which said first comb (14) is movable out of its closed position and said second comb (18) is movable downwards into it open position. 17. A releasable shut-off device as defined in claim 14, in which the rods (13) of said first comb are prolonged by small extensions (26) and the opposite conduit wall is provided with corresponding cavities for receiving said extensions. 18. A releasable shut-off device as defined in one of claims 11-17, in which the rods (13,17) of said combs (14,18) in the region of their external ends have extensions jutting at right angles out of the closure plane, which are affixed to connecting cross-members (20,21) of said rod combs (14,18), which cross-members are arranged to be driven parallel to said closure plane in a path spaced from said closure plane. 19. A releasable shut-off device as defined in one of claims 11-17, in which each of said combs (14,18) is provided with a spindle drive (22,23) spaced to one side of the closure plane of said combs, each comb being provided with roller bearings and guide rails for guiding said combs (14,18) in the course of the closing and opening movements thereof. 20. A releasable shut-off device as defined in one of claims 11-17, in which said shut-off device is enclosed by a double-pressure container (31,32) enclosing the entire paired comb closure system.
	summary
	abstract	A method of removing a radioactive material from a gas includes directing the gas through a bed of salt, wherein the gas includes water vapor and the radioactive material. The salt constitutes more than 50 percent by weight of the bed. The method additionally includes condensing the water vapor in the bed and dissolving a portion of the salt to form a salt solution. The method further includes absorbing the radioactive material into the salt solution while a remainder of the gas passes through the bed. A salt filtration system configured to perform the method may be implemented as a pre-filter (or post-filter) to an existing filter unit or as a standalone filter.
039705170	abstract	A process for compacting a granular radio-active material into a sealed solid body for use as a heat source, the process carried out in a hot-cell which is partially evacuated.
	abstract	The X-ray focusing device includes a point/parallel type multi-capillary X-ray lens (MCX) and a point/parallel type single capillary X-ray lens (SCX). MCX and SCX are positioned so that the end face of the parallel end of SCX is positioned closed to the focal point position on the converging end of MCX so that the optical axes of the two coincide. X-rays that are efficiently collected by MCX are emitted from the converging end and become incident to the end face of parallel end of SCX so that the X-rays are efficiently incorporated into SCX. The X-rays are then irradiated from the converging end of SCX onto focal point having a small diameter. This allows taking advantages of MCX and SCX while compensating for their disadvantages.
	abstract	Thermal subsystems of manufactured information handling systems are tested for compliance with desired parameters by running a thermal diagnostics module in firmware during one or more manufacturing activities performed on the information handling system. The thermal diagnostics module monitors and stores one or more thermal parameters detected at the information handling system, such as the maximum temperature zone detected during a manufacturing activity. The stored thermal parameter is read after the manufacturing activity and compared with an expected value to determine the status of the thermal subsystem. For instance, an information handling system maximum operating temperature is detected by firmware running on an embedded controller during imaging of a hard disk drive and fails thermal testing if the detected maximum operating temperature exceeds a predetermined value, such as a value that would not be reached if the thermal subsystem functioning properly.
	abstract	A containment vessel has an inner shell covering a reactor pressure vessel and an outer shell forming an outer well which is a gas-tight space covering the horizontal outer periphery of the inner shell. The inner shell has a first cylindrical side wall surrounding the horizontal periphery of the reactor pressure vessel, a containment vessel head which covers the upper part of the reactor pressure vessel, and a first top slab connecting in a gas-tight manner the periphery of the containment vessel head and the upper end of the first cylindrical side wall. The outer shell has a second cylindrical side wall surrounding the outer periphery of the first cylindrical side wall, and also has a second to slab connecting in a gas-tight manner the vicinity of the upper end of the second cylindrical side wall and the first cylindrical side wall.
	description	This application claims the benefit of U.S. Provisional Application No. 60/793,662 filed on Apr. 20, 2006, herein incorporated by reference. The United States Government has certain rights in this invention pursuant to Department of Energy Contract No. DE-AC04-94AL85000 with Sandia Corporation. The present invention relates to methods and apparatus for controlling energetic beam processes that modify a surface of a specimen. The present invention additionally relates to methods and apparatus for controllably creating a topography at a surface of a specimen, by energetic beam processes. Energetic beam processes utilize tools that generate, focus, and direct beams comprised of energetic particles, for example, photons, ions, electrons and/or accelerated neutral particles, to modify and/or analyze the surface of the specimen. Such modifications can include creating a topography at a surface. The topography of a surface can be described in terms of locations at the surface (e.g. represented by “x” and “y” positional coordinates) and the relative height or depth (e.g. “z”) of the local surface at those locations. Energetic beam processes can be “additive” in that they add material to a surface, such as in laser thermal chemical vapor deposition, photochemical deposition, electron or ion induced chemical vapor deposition. Energetic beam processes can also be “subtractive” in that they remove material from a surface, such as focused ion beam milling, laser ablation, photochemical etching, sputtering and laser thermal etching. Disclosed are methods and apparatuses whereby an interferometer, integrated with an energetic particle column, is used to monitor and provide feedback control of the depth, shape and/or roughness of features created at the surface of a specimen by energetic beam processes. The methods and apparatuses disclosed are suitable for specimens including planar, multi-planar, faceted, curved, irregular surface profiles and blind holes and, can be practiced in vacuum, atmospheric pressure and/or at pressures higher than atmospheric pressure. The following documents are incorporated herein by reference: U.S. Pat. No. 6,373,070 “Method Apparatus for a Coaxial Microscope with Focused Ion Beam”, issued Apr. 16, 2002 to Rasmussen. Where a conflict exists between the definition of a term in the instant application, and the definition of the same or a similar term in that of an incorporated reference, the definition of the term as defined in the instant application is controlling. The following exemplary embodiments serve to illustrate methods and apparatus for creating a topography at a surface of a specimen, according to the present invention. The methods and apparatus described can be employed on monolithic (single material) and/or heterogeneous (multi-layered and/or multi-material) specimens having flat, planar, irregular, blind holes, and/or curved surfaces. For illustrative purposes, the following examples include embodiments wherein the energetic particles are ions, and the energetic particle column comprises a Focused Ion Beam (FIB) tool. The reader of the instant disclosure will understand that with relatively minor modifications, the energetic particles could equally as well include photons, electrons, ions and/or accelerated neutral species, that are directed to the surface of a specimen. FIG. 1 is a schematic cross-sectional illustration of an embodiment of an apparatus 100 for creating a topography at a surface, according to the present invention. Apparatus 100 comprises an energetic beam tool, illustrated as a FIB tool 102, including an ion column 116 and ion source 106, and a controller 108. The ion column 116 can include focusing and steering mechanisms 118, such as magnetic and or electrostatic deflection coils, apertures, lenses, accelerating plates and focusing coils, for forming ions from the source 106 into an ion beam 110, and directing the ion beam to locations 112 at the surface of a specimen 114. Controller 108 provides a control signal to the ion column 116, which can include control of: the focusing and steering mechanisms 118, the ion source 106 (e.g. the ion output) the accelerating voltage and ion current of the ion beam 110, the dwell time of the ion beam 110 at locations 112, and other elements of the apparatus 100 as described herein, to controllably remove or add material to the surface of the specimen 114. The column 116 can include a beam stop 126 (e.g. a beam blanking mechanism) for trapping the ion beam 110 when it is desired to direct the ion beam 110 away from the surface of the specimen 114. The ion column 116 can extend into a vacuum envelope 122 that additionally can contain the specimen 114 and a specimen stage 124. Apparatus 100 includes a Michelson-type interferometer 120 comprising a light source 128, beam splitter 136, primary objective 134 and an objective mirror 132 arranged to illuminate the locations 112 (e.g. a portion of the locations, or an area comprising the locations) at the surface of the specimen 114 with light from the light source 128. The objective mirror 132 is located between the ion source 106 and the specimen 114 and contains an aperture 154 (e.g. a “pinhole” or “through-hole”) arranged to allow the ion beam 110 to pass through the mirror and onto the surface of the specimen 114. Light 130 exiting the objective 134 is reflected off the objective mirror 132 and onto the surface of the specimen 114. The interferometer 120 is arranged with respect to the FIB tool 102, and ion column 116, such that light 130 from the light source 128 is substantially coincident with the ion beam 110 at the locations 112 at the surface of the specimen 114. The interferometer 120 is said to be integrated with the ion column 116 (i.e. an energetic particle column) wherein the arrangement of the interferometer 120 with the ion column 116 is such as to allow exposing one or more locations at the surface of the specimen 114 to ions (i.e. energetic particles) and simultaneously measuring surface heights at one or more locations by means of the interferometer 120. This provides the capability to determine surface height values simultaneously or sequentially, with energetic particle processing, without for example, the need to transfer a specimen between processing and metrology tools, or re-registration of specimens between processing and metrology stations. The interferometer 120 can include additional optical components such as a collimating objective 142 and lens(es) 144 to control the focus and beam width of the illuminating light 130. A portion of the light 130 illuminating the surface of the specimen 114 (e.g. locations 112) is reflected off the surface and travels a backward path reflecting off the objective mirror 132, through the objective 134, beam splitter 136, mirror 138 and into an imaging device 140. A first optical path 150 of the interferometer 120 includes the distance light travels from the beam splitter 136, through the objective 134, reflects off objective mirror 132 and onto the locations 112 at the surface of the specimen 114. In embodiments where the energetic particles comprise photons, the objective mirror 132 can comprise a dichroic mirror, a polarization beam splitter, a reflective grating or a mirror comprising a pattern of apertures. Additionally, in embodiments where the energetic particles comprise photons, the paths of the energetic particle beam and the light path of the interferometer could be interchanged. Interferometer 120 includes a reference objective 146 and reference mirror 148 comprising a second optical path 152 including the distance light 156, from the light source 128, travels from the beam splitter 136 through the reference objective 146 and to the surface of the reference mirror 148. A portion of the light is reflected off reference mirror 148 and travels back through reference objective 146, beam splitter 136, mirror 138 and into the imaging device 140. A portion of the light 130 reflected off the locations 112, and a portion of light 156 reflected off the reference mirror 148, are received by the imaging device 140 and interferometrically combined to create interference patterns due to changes in the length of the optical paths 150 and 152 and/or the topography of the area 112, at the surface of the specimen 114, due to processing by the beam of energetic particles. The imaging device 140 can be in the form of a charge coupled device (i.e. CCD camera) or other optical imaging device, and can have an electrical, analog or digital output, and can include a monitor or display (not shown) for convenience and observation by a user. The output of the imaging device 140 can be provided to the controller 108 (e.g. a computer) for image processing and/or analysis. In various embodiments of the invention, the controller 108 (e.g. a computer) can be utilized to perform a comparison of interferometric data comprising a current (e.g. currently existing) surface height profile (i.e. topography) of locations at the surface 112, to a desired surface height profile for the locations 112 to determine a difference. A surface height profile (i.e. topography) can comprise a surface height (e.g. “z”) information for one or more locations (i.e. x-y coordinates) at the surface. A difference can comprise subtracting current surface heights from desired surface heights for each of the one or more locations to obtain a height difference (e.g. delta) for each of the one or more locations (e.g. a difference matrix). The controller 108 can then generate (or modify) a control signal 162 for the ion column 116, based upon the difference, to adjust the dose of ions delivered to each of the one or more locations, for example, by providing real-time feedback control of the ion column 116, to produce the desired surface height profile. In practice, the controller 108 can be realized as one or more control devices or computers. The interferometer 120 can comprise two optical paths 150 and 152, and corresponding imaging objectives 134 and 146. Creating interferograms as the topography at the locations 112 at the surface evolves with processing by the ion beam 110, can be facilitated by translating either the specimen 114 or the reference mirror 148 along their respective axis(es) of illumination as defined by their associated optical paths, 150 or 152 respectively. In one embodiment, the reference mirror 148 can be initially positioned in front of the reference objective 146 at a distance equal to the distance between locations 112 at the surface and the primary objective 134, and the reference mirror 148 then translated along the axis of the optical path 152 to generate interferograms, as topography at the locations 112 evolves. In another embodiment, the distance between the reference mirror 148 and the reference objective 146 can remain fixed, while the specimen 114 is translated along the axis of the optical path 150 by moving the specimen stage 124. Maintaining alignment of the axis of the ion beam 110 and the axis of the optical path 150a, to the locations 112 at the surface (e.g. beam and optical axes aligned and perpendicular to the local surface) can be assisted by utilizing a specimen stage 124 having tilt/tip and rotational features. The area of the surface illuminated by the light 130 can be greater than the area comprising the locations 112 at the surface exposed to the ion beam 110. In such embodiments, the illuminated area can include an unexposed area or border (e.g. surrounding the locations 112) which can assist an operator in identifying the progress of a processing operation, i.e. the interferometer can be utilized to measure surface heights at locations not exposed to the ion beam, as well as measuring surface heights at locations 112 exposed to the ion beam. In other embodiments, the area of the surface illuminated by the light 130 can be equal to or less than the area comprising the locations 112 exposed to the ion beam 110. In other embodiments, locations 112 exposed to the ion beam can comprise a plurality of spaced locations, for example, as can occur in embodiments where it is desired to induce roughness at the surface of a specimen. In still other embodiments, a reflection off the surface of the specimen itself can be used as a reference reflection, i.e. as a reference mirror, for making interferometric measurements. In such applications, two optical paths (e.g. 150 and 152) can be combined along a common path, which can be appropriate for instances subject to vibrations, noise or thermally induced variations. In the practice of the present invention, it is not necessary for the specimen 114 to be transparent to light from the light source 128, nor is it required that the specimen 114 be completely opaque to light from the light source 128. It is only required that the specimen reflect enough light to allow the creation of interference patterns by the interferometer. This provides for the present invention to be applicable to a wide variety of specimen materials. For example, if a specimen where transparent and/or thin, reflections off the back (e.g. bottom) surface of the specimen could be problematic. In such cases, the problem can be easily overcome by coating the back surface of the specimen with an index-matching coating that will absorb the incident illumination, thus preventing back surface reflections from interfering with the measurements. In the embodiment as shown in FIG. 1, the reference mirror 148 is illustrated as an optical component separate from the specimen 114. In other embodiments, a reference area can be defined on the specimen surface itself for use as a reflective reference surface (e.g. a reference mirror) the reference area comprising locations not exposed to the ion beam 110. For example, the reference area can be adjacent to the locations 112 being exposed to the ion beam 110. In the embodiment shown in FIG. 1, the imaging device 140 and light source 128 (e.g. a light emitting diode, or “LED”) are illustrated as mounted external to the vacuum envelope 122 and light is communicated into and out of the vacuum envelope 122 by transmission elements that can include a fiber optic cable 166 and an optically transparent view-port 164. Optical and other components (e.g. mounts and shields) associated with the interferometer 120 can be mounted within the vacuum envelope on a translatable mechanism (not shown) for withdrawing these components from the vicinity of the specimen 114 as can be desired on occasion. This can accommodate additive energetic beam processes involving a deposition, for example, a chemical vapor deposition of a material onto the surface of the specimen 114, where gas feed sources are brought into close proximity to the specimen 114 and it can be desired to prevent deposition of materials onto optical components. A secondary electron detector 160 (illustrated as an annular detector) can be mounted above the surface of the specimen 114 to produce images formed by the collection of secondary electrons ejected from the surface of the specimen 114 by the bombardment of the surface by energetic species from the ion beam 110. In embodiments of the invention, the secondary electron detector 160 can be arranged with respect to the other components (e.g. objective 134 and objective mirror 132) within apparatus 100, so as to have a “clear view” of the surface. These images can be useful to an operator in aligning the specimen 114 with the ion and optical components of the apparatus 100. Simultaneous optical and secondary electron imaging of a recognizable feature (e.g. a topographical feature) on the specimen 114 can be used to determine when the axis of the ion beam 110 and the optical path of the interferometer (e.g. 150) are coincident and rotationally aligned, at the surface of the specimen. Alternatively, a point on the specimen stage 124 (e.g. a machined corner) can be used for alignment. In one embodiment of the invention, light source 128 produced light having a wavelength of about 530 nm, interferometer 120 comprised objectives (134 and 146) that were designed and built having a working distance of about 39 mm, a field of view of about 0.2 mm, a numerical aperture (“NA”) of about 0.38, and an in-plane resolution of about 1 μm. The objective design comprised eight lenses arranged as three doublets and two singlets with all spherical surfaces. Lens diameters were on the order of 36 mm with lens face radii ranging from about 16 mm to about 30 mm. The lenses can operate with light of wavelengths from about 510 nm to about 550 nm. The long working distance of these objectives (about 39 mm) allows placing the primary objective 134, external to the ion column 116, thereby not requiring modification of the ion column to accommodate interfacing the ion column 116 to the interferometer 120. In other embodiments, a light source (e.g. laser diode) producing a beam having a shorter wavelength could be employed to improve the system's resolution. Additionally, a charge dissipative coating, for example a coating of indium tin oxide, or other transparent conductive (or charge dissipative) coating, can be applied to the objectives to minimize the effects of charge build-up on the objectives during processing. FIG. 2 illustrates an exemplary method for defining locations at the surface of a specimen 204 (e.g. locations 112 in FIG. 1) within an area 202 at the surface of the specimen 204. An energetic particle beam impinging on the surface of the specimen can have a circular cross-section of diameter “D”. The beam can be rastered across the surface, in a boustrophedonic scanning mode, as indicated by the path 206. The path of the ion beam can be modeled as a matrix of “X-Y” coordinate locations representing the central position of the energetic particle beam, i.e. (Xi, Yj) whereat the beam can reside for a time (e.g. including times of zero duration) and then be directed on to another X-Y coordinate location. The X-Y coordinate locations can be uniformly spaced within the area 202, and separated by a distance “S”, corresponding to filling the area 202 with circles equivalent to a beam of diameter “D” and overlapping by an amount “h”. Focused ion beams can have a near-Gaussian intensity distribution with the full-width at half maximum (i.e. “FWHM”) diameter of the intensity distribution, represented in FIG. 2 by the dimension “D”. The amount of beam overlap with respect to the FWHM can be set to a dimension “h” in both X and Y directions as shown, or can as well be independently set in the two opposing directions (X and Y). The origin of the X-Y coordinate system (i.e. “0,0”) can be assigned to a physical feature at the surface of the specimen, and can be located external (as shown) or within the area 202 comprising the (Xi, Yj) locations exposed to the beam. The location of the origin is a matter of convenience and could as well be assigned to some other physical feature or fiducial, including for example, a location on a specimen support or stage. The area 202 is illustrated as rectangular, but could comprise any shape or outline as convenient for a given application. For example, the area can be a square, a rectangle, a circle, an annulus or other shape of convenience, and can include one or more separate or spaced areas as may be required by an application. The example makes use of a Cartesian coordinate system, but other coordinate systems, for example, a polar coordinate system could be used as well. FIG. 3 illustrates an embodiment of a method 300 for creating a topography at the surface of a specimen, according to the present invention. In this example, controlled doses of energetic particles can be delivered to specified locations at the surface of the specimen to produce a desired topography (e.g. a surface profile). A dose of energetic particles is defined as the number of energetic particles per unit area imparted to a location. A “dose” can also be defined in terms of X-Y coordinates for a plurality of locations at a surface, and the number of energetic particles per unit area delivered to each of the X-Y coordinate locations. Doses can be controlled by a number of methods, including for example, fixing the current (i.e. the number of energetic particles per unit time) of a beam of energetic particles and controlling the time the energetic particle beam resides at a given location (i.e. controlling the dwell time of the beam at each X-Y location). Alternatively, the dwell time of the beam can be fixed for each location and the beam current varied. In other embodiments, the accelerating voltage of a beam of energetic particles can be varied to affect the control of a “dose” of accelerated particles. The latter can be convenient in processes where a material removal or additive rate is a function of the accelerating voltage of the beam. The method starts at step 302. At step 304 the X-Y coordinates and desired surface height values for locations at the surface of a specimen are defined. This can for example, comprise a matrix input to a controller including X-Y coordinate locations within an area, and values for the desired heights (or depths) of the surface at those locations. A mapping of X-Y locations and surface height values can be used to describe a topography at a surface, alternatively referred to as a “surface profile”. Desired X-Y surface height information can for example, be generated by automated computer design tools. Height information can be referenced to the original position of the surface, e.g. the original position of the surface can represent “0” height, and desired surface height values can be negative for example, where subtractive processing is employed, or positive where additive processing is employed. This approach is one exemplary method that can be used where an initially flat specimen is to be processed by an energetic particle beam, to achieve a desired surface profile. At step 306 the controller can be utilized to direct the energetic particle beam to the locations at the surface of the specimen, exposing the locations to doses of energetic particles. For exemplary embodiments utilizing a focused ion beam (FIB) to mill (i.e. etch) a topography into a surface, doses can be determined by assigning ion beam dwell time values to the locations at the surface, i.e. setting beam dwell times to a pre-determined value or alternatively, calculating beam dwell time values by estimating the ion dose(s) required to remove a specific amount of material at a location. Methods for estimating ion dose(s) based on calculations of material removal rates are described elsewhere, see for example, M. J. Vasile, J. Xie, and R. Nassar, “Depth Control of Focused Ion-Beam Milling From a Numerical Model of the Sputter Process”, J. Vac. Sci Technol. B 17 (1999) pp 3085-3090, and D. Adams, M. Vasile and T. Mayer, “Focused Ion Beam Sculpting Curved Shape Cavities in Crystalline and Amorphous Targets”, submitted to the J. Vac. Sci Technol. B (2006). These calculations for required ion dose per location can account for several factors including the ion beam spatial distribution (i.e. the FWHM) and the angular dependence of the removal rate, often referred to as yield (i.e. atoms removed per incident ion). The ion beam spatial distribution can be useful to consider as while the majority of the beam may be incident upon a given location, there can be portions of the beam incident upon neighboring locations (see for example, the beam overlap “h” in FIG. 2). The angular dependence of the sputter yield can also be useful to consider as a surface profile develops with exposure to the ion beam. For example, in creating a curved surface profile, a range of surface normal angles relative to the axis of the ion beam can develop over the area being processed (i.e. as a function of X-Y coordinate location). The estimated ion dose at each location can account for an evolving curved surface having a specific angle of incidence that can influence the sputter yield at that location. Sputter yield and its dependence on the angle of incidence of the ion beam can be determined by experiment or estimated by calculations based on semi-empirical formulations. For exemplary embodiments where the desired surface height at a location is greater than the initial surface height, doses can be estimated based on experimental measurements or calculations of the dose(s) required to add a specific amount of material at a location, for example by a deposition process (e.g. ion induced chemical vapor deposition). Doses can be controlled by a number of methods as described above, including for example, by controlling the dwell time of an energetic beam at locations at the surface. At step 306 the controller can direct the energetic particle column to expose locations at the surface of the specimen to doses of energetic particles. While this could comprise scanning an energetic particle beam across the surface in one pass, and varying the dose of particles delivered to the locations within one scan or pass, it can be convenient to partition the delivered doses into multiple passes (e.g. on the order of 10,000 to 1,000,000 passes, i.e. scans). Partitioning doses into multiple scans can be employed in various embodiments, for example in etching processes, to minimize the effects of re-deposition of material removed from a surface. For an exemplary embodiment wherein doses are controlled by controlling the dwell time of the energetic particle beam at the locations, the dwell time values can be derived from the calculated doses, the beam current and the number of specified scans, if dose partitioning is implemented. At step 308 current surface height values for the locations are measured interferometrically. This can be accomplished for example, by fixing the position of a reference mirror, and translating the specimen along the axis of the beam (see for example the arrangement illustrated in FIG. 1) and generating interference patterns. This could also be accomplished by fixing the position of the specimen, and translating a reference mirror or other mirror disposed along an optical path of the interferometer. In some embodiments of the invention, the output of the interferometer (for example, a digital imaging device attached to the interferometer) can be provided to a controller for processing the interferograms to generate the surface height values. This can be accomplished for example, on a pixel by pixel basis of a digital imaging device. In various embodiments of the invention, the area measured by the interferometer can include an unexposed area or border (e.g. surrounding the exposed locations) which can assist an operator in identifying the progress of a processing operation, i.e. the interferometer can be utilized to measure surface heights at locations not exposed to the ion beam, as well as measuring surface heights at locations exposed to the ion beam. In other embodiments, the area of the surface measured by the interferometer can be equal to or less than the area comprising the locations exposed to the ion beam. In other embodiments, locations exposed to the ion beam can comprise a plurality of spaced locations, for example, as can occur in embodiments where it is desired to induce roughness at the surface of a specimen. At step 310 the controller can be utilized to compare the measured, current surface height values to the desired surface height values to compute a difference. For example, the difference can comprise a plurality of difference values, one for each of the locations at the surface. At step 312, if the difference is within acceptable limits i.e. “delta”, the method ends at step 314. Delta can represent either an absolute height difference or a percentage of the desired surface height values. Delta can comprise a plurality of delta values, e.g. one for each location at the surface. At step 316, if the difference for one or more locations is not within the acceptable limit (i.e. delta) the controller can be utilized to calculate (e.g. estimate) modified (e.g. updated) doses for those locations, and the method returns to step 306 wherein these locations are exposed to the beam according to the modified doses. The cycle can be repeated as necessary to achieve the desired surface height values at each of the locations (i.e. the desired topography). In FIG. 3, at step 306, exposing the locations to the beam of energetic particles, and the step 308, making interferometric measurements, can occur simultaneously or sequentially. Simultaneous interferometric measurements can be obtained while the surface of the specimen is exposed to the energetic particle beam. Sequential measurements can occur during operations where the energetic particle beam is momentarily blanked, directed away from the surface of the specimen, or the source of energetic particles switched off (e.g. energetic beam turned off) while the interferometric measurement is made. The order of making an interferometric measurement(s) and exposing the surface of the specimen to the energetic beam can be selected as convenient for an application. In embodiments where the energetic particle beam is being used to modify the roughness of an area at a surface, doses at step 306, can be directed to expose or dose only selected portions i.e. defined by a subset of locations, at the surface. The locations at the surface of the specimen processed by the beam, and measured interferometrically, can include portions of the surface that are flat, planar or curved, and can contain blind holes and features, as there is no need for the beam to pass through the specimen. FIG. 4 illustrates another embodiment of a method 400 according to the present invention. In this example, doses of energetic particles received at locations on the surface of a specimen can be controlled, as a beam of energetic particles is rastered (e.g. scanned) across the surface. The method starts at step 402. At step 404 X-Y coordinates for locations at the surface and initial, as well as desired surface height values are defined for the X-Y locations. This can for example, comprise inputting matrices to a controller including X-Y coordinate locations within a defined area, and values for the initial and desired heights (or depths) of the surface at those locations. Desired X-Y-surface height information can for example, be generated by automated computer design tools. Initial (e.g. pre-existing) surface height information can as well comprise a computer generated model of the surface or can comprise interferometrically generated information. The latter can be convenient in embodiments wherein it is desired to process a surface that is not initially flat, or where a specimen to be processed comprises a surface having curvature, and/or irregular surface features. At step 406 the controller can be utilized to compare the desired surface height values to the initial surface height values to compute a difference. For example, the difference can comprise a difference for each of the locations at the surface. The controller can then calculate doses for the locations, using the methods described above. At step 408 the controller can be utilized to direct the energetic particle beam to the locations at the surface of the specimen, exposing the locations to the calculated doses of energetic particles. As described above, partitioning doses into multiple scans can be employed in various embodiments for example, to minimize the effects of re-deposition of material removed from a surface. For an exemplary embodiment wherein doses are controlled by controlling the dwell time of the energetic particle beam at the locations, the computed dwell times are derived from the calculated doses, the beam current, and the number of specified scans, if dose partitioning is implemented. At step 410 current surface height values for the locations are measured interferometrically. This can be accomplished for example, by fixing the position of a reference mirror, and translating the specimen along the axis of ion beam and generating interference patterns. This could also be accomplished by fixing the position of the specimen, and translating a reference mirror or other mirror disposed along an optical path of the interferometer. In embodiments of the invention, the output of the interferometer (for example, a digital imaging device attached to the interferometer) can be provided to a controller for processing the interferograms to generate the surface height values. This can be accomplished for example, on a pixel by pixel basis of a digital imaging device. At step 412 the controller can be utilized to compare the measured current surface height values to the desired surface height values to compute a difference. For example, the difference can comprise a difference for each of the locations at the surface. At step 414, if the difference is within acceptable limits i.e. “delta”, the method ends at step 418. Delta can represent either an absolute height difference or a percentage of the desired surface height values. Delta can comprise a plurality of delta values, e.g. one for each location at the surface. At step 416, if the difference (for one or more locations) is not within an acceptable limit (i.e. delta) the controller can be utilized to calculate (e.g. estimate) modified (i.e. updated) doses for those locations, and the method returns to step 408 wherein the locations are exposed to the ion beam according to the modified doses. The cycle can be repeated to achieve the desired surface height values at the locations (i.e. the desired topography). In exemplary embodiments of the invention according to FIG. 1, it can occur that an optical interferometer can resolve an X-Y coordinate location as an area having dimensions of about 1 μm by about 1 μm. A focused ion beam tool can have a much finer resolution. For example, a focused ion beam tool can resolve the same 1 μm by 1 μm area as approximately 82×82 locations. The “optical pixel” e.g. about 1 μm by about 1 μm, in this example is larger than the “FIB pixel”, e.g. 82×82 FIB pixels can be contained within a given optical pixel. In this example, the FIB tool can process (i.e. expose) much smaller areas than can be measured by the interferometer. FIG. 5 is a schematic illustration of a situation where FIB pixel dimensions are smaller than the optical pixel dimensions. At a given X-Y location for which a surface height can be interferometrically determined, the area resolved and measured by the interferometer comprises approximately 5 by 5 (for illustrative convenience only) pixel locations. In an example where a flat bottomed feature of a single surface height is desired, the surface heights of the optical pixels can be interferometrically measured and ion doses can be calculated based on this measurement. The calculated doses can then be assigned equally to each of the FIB pixels contained within the corresponding optical pixel. In another example that involves processing of a sloping or curved feature, the surface height of a given optical pixel and surrounding optical pixels can be considered to define a local net shape. The focused ion beam pixels contained at the centers of the measured optical pixels can be assigned surface heights based on the measurements for the corresponding optical pixels. The remaining focused ion beam pixels (not corresponding to a center of an optical pixel) can be treated by inferring the surface height (e.g. using linear, quadratic or other interpolation methods) at each FIB pixel location based on estimating the local slope using the surface height measurements of neighboring optical pixels. Doses can be calculated for these “off-center” FIB pixels based on the interpolated surface heights and other considerations, such as the specific rate of milling at a particular angle of incidence (as described above). Another situation can arise where an interferometer has an optical resolution of about 1 μm and the focused ion beam instrument has a comparable resolution (e.g. an ion beam FWHM of about 1 μm). As for the prior example, the surface profile information determined by the optical interferometer throughout ion beam processing, can be used to update the depths of different locations at the surface and doses required to achieve a desired topography can be calculated based on the interferometric measurements. In this example, there can be a near 1 to 1 resolution of locations between the interferometer and the ion column, and the measured surface height values used directly to calculate doses, with no interpolation required. FIG. 6 illustrates another situation, wherein FIB pixels can be larger than the optical pixels resolvable by an optical interferometer. For example, where for illustrative purposes, 4 optical pixels fit within one FIB pixel, individual measurements from the optical pixels within the FIB pixel can be averaged, and this averaged surface height value assigned to the location of the FIB pixel. A calculation of a dose to be received at a location, i.e. within a FIB pixel, can be based on the average of the surface height values measured for the corresponding four optical pixels. Embodiments of the present invention include methods to produce a topography at the surface of a specimen by controlling the dose of energetic particles received at specified locations at the surface of the specimen. Exemplary methods control dose by commanding the dwell time of an ion beam at those specified locations. Alternatively, other embodiments of the methods can control dose by specifying a subset of locations that are not exposed to the ion beam. In this latter mode, locations can be removed from the matrix of locations to be exposed to the beam once the desired surface height values are attained at those locations. This approach can be useful in that dwell times for locations to be exposed can be near constant or equal. The above described exemplary embodiments present several variations of the invention but do not limit the scope of the invention. Those skilled in the art will appreciate that the present invention can be implemented in other equivalent ways. The actual scope of the invention is intended to be defined in the following claims.
048636770	abstract	A nuclear power plant includes a containment for containing activity carriers. An outlet in the form of an excess pressure safety device leads out of the containment. A filter connects the outlet to the atmosphere. The filter includes a container, a washing fluid disposed in the container, a Venturi scrubber being integrated in the container and connected to the outlet, the container having an upper region with a gas outlet, and a stack connected to the gas outlet.
	summary
	description
	abstract	A radiation attenuation system for use with Computed Tomography procedures is disclosed. The system includes a shield made of a radiation attenuation material and may be useful in blocking or attenuating radiation, and assisting in the protection of at least one of a patient and a medical personnel present during the Computed Tomography procedure. The system may be useful for both Computed Tomography scanning procedures and Computed Tomography fluoroscopy procedures.
	claims	1. A method of permitting movement of a nuclear reactor component within a nuclear reactor, comprising:sensing a mast and grapple location;sensing a grapple orientation by configuring a cam, attached to a gimbal plate, such that the cam and the gimbal plate rotate in unison and in response to an angular rotation of the grapple while detecting a position of the cam using a plurality of switches positionable in proximity to the gimbal plate, the cam, the gimbal plate and the grapple configured to rotate bi-directionally and in a same direction with each other;calculating whether the sensed location and the sensed orientation, respectively, match a requested pick-up location and a requested pick-up orientation; andprohibiting lowering and grasping of the grapple, unless the sensed location and sensed orientation match the requested pick-up location and the requested pick-up orientation. 2. The method of claim 1, further comprising:inputting a plurality of requested pick-up locations and requested pick-up orientations, and the sequential order of the pick-up locations, using a user interface. 3. The method of claim 2, wherein the requested pick-up location and the requested pick-up orientation correspond to the pick-up locations and orientations of nuclear reactor components described on a nuclear reactor move-sheet. 4. The method of claim 1, further comprising:displaying the sensed location and the sensed orientation on a user interface screen. 5. A method of permitting movement of a nuclear reactor component within a nuclear reactor, comprising:sensing a mast and grapple location;sensing a grapple orientation by configuring a cam, attached to a gimbal plate, such that the cam and the gimbal plate rotate in unison and in response to an angular rotation of the grapple while detecting a position of the cam using a plurality of switches positionable in proximity to the gimbal plate, the cam, the gimbal plate and the grapple configured to rotate bi-directionally and in a same direction with each other;calculating whether the sensed location and the sensed orientation, respectively, match a requested drop-off location and a requested drop-off orientation;prohibiting the lowering and grasping of the grapple, unless the sensed location and the sensed orientation match the requested drop-off location and the requested drop-off orientation. 6. The method of claim 5, further comprising:inputting a plurality of requested pick-up locations and requested pick-up orientations, and the sequential order of the pick-up locations, using a user interface. 7. The method of claim 6, wherein the requested pick-up location and the requested pick-up orientation correspond to the pick-up locations and orientations of nuclear reactor components described on a nuclear reactor move-sheet. 8. The method of claim 5, further comprising:displaying the sensed location and the sensed orientation on a user interface screen.
052176800	claims	1. In combination, a source of liquid, a closed liquid storage tank for filling of liquid into a high-temperature and high-pressure vessel, said tank having a liquid inlet for receiving liquid from said source of liquid, a piping communicating said liquid inlet with said liquid source through which liquid from said liquid source can flow to said tank when the pressure within the closed liquid tank is relatively lower than the pressure within the liquid source, a check valve for checking the flow of said liquid from said liquid storage tank toward said liquid source by way of said piping while not checking the liquid flow from said liquid source to said closed liquid storage tank, said storage tank further including a pressure inlet through which the pressure from the high-temperature and high-pressure vessel can be introduced into said liquid storage tank via a valve, and said storage tank having a liquid supply port for supplying liquid of said tank into said high-temperature and high-pressure vessel via a valve. 2. The combination according to claim 1, further comprising a heat dissipation means for dissipating heat from said tank. 3. A liquid filling method for high-temperature and high-pressure vessel, comprising the steps of placing the interior of said high-temperature and high-pressure vessel and the interior of a closed liquid storage tank in communication with one another to make the respective pressures therein equal to each other and then filling liquid from said closed liquid storage tank into said high-temperature and high-pressure vessel by the action of gravitational force, said liquid filling method further comprising interrupting said communication between the interior of said high-temperature and high-pressure vessel and the interior of said closed liquid storage tank, dissipating the heat within said closed liquid storage tank to the outside thereof to cause a decrease in level of the pressure therewithin to a pressure lower than the pressure in a source of liquid which is continuously communicated with said closed storage tank in a manner which permits flow from said source in the direction of said tank but not in the direction from said tank to said source, and causing a liquid of said liquid source to be sucked into said closed storage tank as a result of the pressure differential between the pressures in said tank and said source to thereby cause the liquid to be stored in said tank.
	claims	1. A method for changing the physical character of a material, the method comprising:providing a material sample including atoms that are nuclearly transmutable via bombardment by helium three ions, wherein said material sample includes a semiconducting solid-state crystalline zinc oxide film; andirradiating said material sample with helium three ions so as to effect transmutation, to nitrogen atoms, of oxygen atoms that are contained in said zinc oxide film, said transmutation being of 16O to 15N. 2. The method for changing of claim 1 wherein said irradiating includes causing a beam of helium three ions to be incident upon said material sample. 3. The method for changing of claim 1 wherein said irradiating results in changing at least one physical characteristic of said material sample, said physical characteristic being selected from the group consisting of electronic carrier concentration, electronic carrier type, resistivity, photoconductivity, luminescence, and morphology. 4. The method for changing of claim 1 wherein said transmutation further includes transmutation, to fluorine atoms, of oxygen atoms that are contained in said zinc oxide film, said transmutation being of 16O to 18F. 5. The method for changing of claim 4 wherein said irradiating includes causing a beam of helium three ions to be incident upon said material sample. 6. The method for changing of claim 1 wherein said transmutation includes:transmutation, via bombardment, of 16O to 15O; andtransmutation, via decay by positron emission, of 15O to 15N. 7. The method for changing of claim 6 wherein said irradiating includes causing a beam of helium three ions to be incident upon said material sample. 8. The method for changing of claim 6 wherein said irradiating results in changing at least one physical characteristic of said material sample, said physical characteristic being selected from the group consisting of electronic carrier concentration, electronic carrier type, resistivity, photoconductivity, luminescence, and morphology. 9. The method for changing of claim 8 wherein said irradiating includes causing a beam of helium three ions to be incident upon said material sample. 10. The method for changing of claim 9 wherein said transmutation further includes transmutation, to fluorine atoms, of oxygen atoms that are contained in said zinc oxide film, said transmutation being of 16O to 18F. 11. A method for doping a material, the method comprising:positioning a target entity in a chamber of a particle accelerator apparatus, said target entity including a material film containing semiconducting solid-state zinc oxide; andirradiating said target entity with 3He ions via a high energy beam so that transmutation results in said target entity of at least some oxygen atoms to nitrogen atoms, said transmutation including transmutation, to 15N, of 16O contained in said zinc oxide, wherein said transmutation of 16O to 15N includes:transmutation, via bombardment, of 16O to 15O; andtransmutation, via decay by positron emission, of 15O to 15N. 12. The method for doping of claim 11, wherein said target entity prior to said irradiation is lower in at least one of resistance and photoconductivity than is said target entity subsequent to said irradiation. 13. The method for doping of claim 11, wherein said zinc oxide is crystalline. 14. The method for doping of claim 11, wherein said irradiating includes causing a beam of helium three ions to be incident upon said material film. 15. The method for doping of claim 11, wherein said irradiating results in changing at least one physical characteristic of said material film, said physical characteristic being selected from the group consisting of electronic carrier concentration, electronic carrier type, resistivity, photoconductivity, luminescence, and morphology. 16. The method for doping of claim 15, wherein said irradiating includes causing a beam of helium three ions to be incident upon said material film. 17. The method for doping of claim 16, wherein said transmutation further includes transmutation, to fluorine atoms, of oxygen atoms that are contained in said zinc oxide, said transmutation being of 16O to 18F. 18. A method for changing the physical character of a material, the method comprising:providing a material film including atoms that are nuclearly transmutable via bombardment by helium three ions, wherein said material film includes semiconducting solid-state zinc oxide; andirradiating said material film with helium three ions so as to effect transmutation, to nitrogen atoms, of oxygen atoms that are contained in said zinc oxide, said transmutation being of 16O to 15N. 19. The method for changing of claim 18 wherein:said material film is crystalline;said irradiating includes causing a beam of helium three ions to be incident upon said material film;said irradiating results in changing at least one physical characteristic of said material film, said physical characteristic being selected from the group consisting of electronic carrier concentration, electronic carrier type, resistivity, photoconductivity, luminescence, and morphology;said transmutation includes: transmutation, via bombardment, of 16O to 15O; and transmutation, via decay by positron emission, of 15O to 15N.
056493231	abstract	The present invention provides a composition and process for disposal of radioactive, hazardous and mixed wastes. The present invention preferably includes a process for multibarrier encapsulation of radioactive, hazardous and mixed wastes by combining substantially simultaneously dry waste powder, a non-biodegradable thermoplastic polymer and an anhydrous additive in an extruder to form a homogenous molten matrix. The molten matrix may be directed in a "clean" polyethylene liner, allowed to cool, thus forming a monolithic waste form which provides a multibarrier to the dispersion of wastes into the environment.
	abstract	The invention relates to the handling of radioactive material. For instance, a radiation shield of the invention may include a body having a cavity therein for receiving radioactive material. An opening to the cavity may be defined in the body. A base may be releasably attachable to the body (generally toward the opening) to at least partially enclose the radioactive material in the cavity. In the case that the radiation shield includes a plurality of interchangeable bases, one of the bases may have at least one of a shorter length and a lighter weight than another of the bases. The base(s) may be designed to enclose more than one size and/or shape of container in the cavity. The base(s) may include a hand grip to facilitate manual gripping of the radiation shield. The base(s) may include a guard to reduce exposure to radiation from manual handling of the radiation shield.
	description	This present application is a U.S. national stage under 35 U.S.C. § 371 of International Application No. PCT/CN2015/098891, filed on Dec. 25, 2015, designating the United States of America, the contents of which are hereby incorporated by reference. The present disclosure generally relates to a radiation based imaging system, and more particularly, to a grid for a detector and a radiation imaging system including such a detector. A radiation detection or imaging system may be used in many fields such as medical diagnosis and therapy, industrial production and application, scientific experiments and research, national security, etc. Generally, radiation detection or imaging may refer to a technology that may allow non-invasive observation of the interior of an object using radiation. As used herein, radiation may include a particle ray (for example, neutron, proton, electron, μ-meson, heavy ion, etc.), a photon ray (for example, X-ray, γ-ray, α-ray, β-ray, ultraviolet, laser, etc.), or the like, or any combination thereof. The information acquired by a radiation based imaging system may include, e.g., structure, density, or lesions, etc., without damaging the object. The term “object” as used herein may include a substance, a tissue, an organ, a specimen, a body, or the like, or any combination thereof. The term “target” may be used interchangeably with the term “object.” For different objects to be imaged, different spatial resolutions may be needed. Thus, an apparatus, system, and method to adjust the spatial resolution are desired. In an aspect of the present disclosure, a system is provided. The system may include a radiation source, a detector, and a first grid. The radiation source may be configured to generate radiation. The detector may include a plurality of detector cells. The first grid may be located between the radiation source and the detector cells. The first grid may include a plurality of radiation transmitting sections. At least one of the plurality of detector cells may include an active area which may be configured to receive radiation from the radiation source that passes through at least one of the plurality of radiation transmitting sections of the first grid. The active area may be adjustable by adjusting the first grid. The radiation source, the first grid and the detectors cells may be operatively coupled for detecting an object. As used herein, “coupled” or “operatively coupled” may indicate that one or more components may work either alone or in combination cooperatively to achieve a function including, for example, detecting an object, adjusting a parameter of an imaging device or an image, etc. In another aspect of the present disclosure, a method is provided. The method may include locating a first grid between a radiation source and a detector. The detector may include a plurality of detector cells and the first grid may include a plurality of radiation transmitting sections. The method may further include emitting radiation from the radiation source toward the first grid and receiving, on an active area of at least one of the plurality of detector cells, the radiation that passes through the first grid. The active area may be adjustable by adjusting the first grid. The radiation source, the first grid and the detectors cells may be operatively coupled for detecting an object. In some embodiments, the active area may be adjustable by adjusting the position of the first grid. In some embodiments, the active area may be adjustable by tilting the first grid by an angle. In some embodiments, the angle may be any value between 0° to 360°. In some embodiments, the system may further include a shielding device which may be configured to adjustably block the radiation source. In some embodiments, the configuration of the shielding device may be in the form of a slip sheet, a shutter, a rotation blade, or the like, or a combination thereof. In some embodiments, the system may further include a second grid. The second grid may be located between the first grid and the detector. In some embodiments, the first grid and the second grid may be moveable relative to each other. In some embodiments, the first grid may be parallel to the second grid. In some embodiments, the first grid may be arranged at an angle to the second grid. In some embodiments, the second grid may include a plurality of radiation transmitting portions, and at least one of the plurality of radiation transmitting portions may be coupled with an active area of a detector cell. In some embodiments, the extending direction of the radiation transmitting sections of the first grid and the extending direction of the radiation transmitting portions of the second grid may be different. In some embodiments, the active area of a detector cell may be at least partially determined by the at least one of the plurality of radiation transmitting sections of the first grid and at least one of the plurality of radiation transmitting portions of the second grid. In some embodiments, at least one of the plurality of radiation transmitting sections may extend in a first direction. In some embodiments, the first grid may be moveable in a second direction perpendicular to the first direction. In some embodiments, the second grid may be moveable in the first direction. In some embodiments, the first direction may be parallel, or perpendicular to, or at an oblique angle with the second direction. In some embodiments, the angle between the first direction and the second direction may be any degrees, e.g., 10°, 15°, 20°, 25°, 30°, 40°, 45°, 60°, 75°, or the like. In some embodiments, the radiation source may include a plurality of focal spots. The trajectory of the focal spot may be continuous or discrete. In some embodiments, the continuous trajectory may be a line, a sine curve, a sawtooth wave, or other regular or other irregular shape. In some embodiments, for the discrete trajectory, the number of the positions of the focal spot may be an arbitrary value, e.g., two, three, four, five. In some embodiments, the object may be scanned by the radiation form at least two different focal spots of the radiation source. Additional features will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following and the accompanying drawings or may be learned by production or operation of the examples. The features of the present disclosure may be realized and attained by practice or use of various aspects of the methodologies, instrumentalities and combinations set forth in the detailed examples discussed below. In the following detailed description, numerous specific details are set forth by way of examples in order to provide a thorough understanding of the relevant disclosure. However, it should be apparent to those skilled in the art that the present disclosure may be practiced without such details. In other instances, well known methods, procedures, systems, components, and/or circuitry have been described at a relatively high-level, without detail, in order to avoid unnecessarily obscuring aspects of the present disclosure. Various modifications to the disclosed embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirits and scope of the present disclosure. Thus, the present disclosure is not limited to the embodiments shown, but to be accorded the widest scope consistent with the claims. It will be understood that the term “system,” “unit,” “module,” and/or “block” used herein are one method to distinguish different components, elements, parts, section or assembly of different level in ascending order. However, the terms may be displaced by other expression if they may achieve the same purpose. It will be understood that when a unit, module or block is referred to as being “on,” “connected to” or “coupled to” another unit, module, or block, it may be directly on, connected or coupled to the other unit, module, or block, or intervening unit, module, or block may be present, unless the context clearly indicates otherwise. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. The terminology used herein is for the purposes of describing particular examples and embodiments only, and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “include,” and/or “comprise,” when used in this disclosure, specify the presence of integers, devices, behaviors, stated features, steps, elements, operations, and/or components, but do not exclude the presence or addition of one or more other integers, devices, behaviors, features, steps, elements, operations, components, and/or groups thereof. The present disclosure generally relates to a radiation based imaging system. Specifically, the disclosure provides a grid configured for adjusting an active area on a detector cell, and a radiation based imaging system including a radiation source, a detector including a plurality of detector cells, and a grid including a plurality of radiation transmitting sections. The grid may be adjusted so as to adjust an active area receiving radiation from the radiation source on the detector cells. This may allow adjustment of the spatial resolution of the imaging system such that the system may provide various spatial resolutions by adjusting, for example, the grid. The following description is provided in the exemplary contexts of an X-ray imaging system or a CT scanner for illustration purposes, and not intended for limiting the scope of the present disclosure. The system and method disclosed herein may be applicable to other radiation based imaging system. For brevity, a radiation based imaging system may be referred to as a system, or an imaging system in the present disclosure. FIG. 1 illustrates a block diagram of the X-ray imaging system 100 according to some embodiments of the present disclosure. As shown in the figure, the X-ray imaging system 100 may include a gantry 101, an object table 102, a high voltage generator 103, an operational control computer 104, an image generator 105, and an operator console and display 106. The gantry 101 may be configured to house the components needed to produce and detect X-rays to generate a CT image. The gantry 101 may include an X-ray tube 108 and a detector 107. It should be noted that in alternative embodiments of the present disclosure, the high voltage generator 103 may be located in the gantry 201. The X-ray tube 108 may be configured to emit radiation that may be received by the detector 107 after it passes through an object exposed in the aperture of the gantry 101. Merely by way of example, the radiation may include a particle ray, a photon ray, or the like, or any combination thereof. The particle ray may include neutron, proton, electron, μ-meson, heavy ion, or the like, or any combination thereof. The photon beam may include X-ray, γ-ray, α-ray, β-ray, ultraviolet, laser, or the like, or any combination thereof. The object may include a substance, a tissue, an organ, an object, a specimen, a body, or the like, or any combination thereof. In some embodiments, the X-ray tube 108 may be a cold cathode ion tube, a high vacuum hot cathode tube, a rotating anode tube, etc. The shape of the X-ray beam emitted by the X-ray tube 108 may be a line, a narrow pencil, a narrow fan, a fan, a cone, a wedge, an irregular shape, or the like, or any combination thereof. The shape of the detector 107 may be flat, arc-shaped, circular, or the like, or any combination thereof. The fan angle of the arc-shaped detector may be an angle from 0° to 360°. The fan angle may be fixed or adjustable according to different conditions including, for example, the desired resolution of an image, the size of an image, the sensitivity of a detector, the size or distribution of detector cells on the detector, the stability of a detector, or the like, or any combination thereof. In some embodiments, the pixels of the detector 107 may be the number of the detector cells, e.g., the number of scintillator or photodetector, etc. The pixels of the detector may be arranged in a single row, two rows, or another number of rows. The X-ray detector may be one-dimensional, two-dimensional, or three-dimensional. The high voltage generator 103 may be configured to produce high voltage and/or current, and transmit it to the X-ray tube 108. The voltage generated by the high voltage generator 103 may range from 80 kV to 140 kV, or from 120 kV to 140 kV. The current generated by the high voltage generator may range from 20 mA to 500 mA. In alternative embodiments of the present disclosure, the voltage generated by the high voltage generator 103 may range from 0 to 75 kV, or from 75 kV to 150 kV. The operational control computer 104 may be configured to communicate bidirectionally with the gantry 101, the tube 108, the high voltage generator 103, the object table 102, the image generator 105, and/or the operator console and display 106. Merely by way of example, the gantry 101 may be controlled by the operational control computer 104 to rotate to a desired position that may be prescribed by a user via the operator console and display 106. The operational control computer 104 may be configured to control the generation of the high voltage generator 103, for example, the magnitude of the voltage and/or the current generated by the high voltage generator 103. As another example, the operational control computer 104 may be configured to control the display of images on the operator console and display 106. For instance, the whole or part of an image may be displayed. In some embodiments, an image may be divided into several sub-portions, which may be displayed on a screen at the same time or in a certain order. According to some embodiments of the present disclosure, the user or the operator may select one or more sub-portions to display according to some conditions. Merely by way of example, the user may specify that an enlarged view of a sub-portion is to be displayed. The operator console and display 106 may be coupled with the operational control computer 104 and the image generator 105. In some embodiments, the operator console and display 106 may be configured to display images generated by the image generator 105. In alternative embodiments, the operator console and display 106 may be configured to send a command to the image generator 105, and/or the operational control computer 104. Still in alternative embodiments of the present disclosure, the operator console and display 106 may be configured to set parameters for a scan. The parameters may include acquisition parameters and/or reconstruction parameters. Merely by way of example, the acquisition parameters may include tube potential, tube current, focal spots in the tube, recon parameters (e.g., slick thickness), scanning time, collimation/slice width, beam filtration, helical c, or the like, or any combination thereof. The reconstruction parameters may include reconstruction field of view, reconstruction matrix, convolution kernel/reconstruction filter, or the like, or any combination thereof. The object table 102 may be configured to support a patient and move though the aperture of the gantry 101 during an examination. As shown in FIG. 1, the direction of a patient being transmitted during an examination is along the Z-direction. Depending on the ROI of the patient selected or the protocols selected, the patient may be positioned supine or prone, and either feet or head first. In some embodiments of the present disclosure, the object table 102 may be indexed between multiple scans. In some embodiments of the present disclosure, the object table 102 may be transmitted through the gantry 101 at a constant speed. The speed may relate to the length of the area to be scanned, the total scanning time, the pitch selected, or the like, or any combination thereof. In some embodiments, the object table 102 may be used to support an object other than a patient. Such a structure may move the object for examination through the X-ray imaging system. For brevity, such a structure may also be referred to a patient. It should be noted that the description of the X-ray imaging system is provided for the purposes of illustration, and not intended to limit the scope of the present disclosure. For persons having ordinary skills in the art, various variations and modifications may be conduct under the teaching of the present disclosure. However, those variations and modifications may not depart from the protecting of the present disclosure. For example, the gantry 101 may further include a microphone, sagittal laser alignment light, patient guide lights, X-ray exposure indicator light, energy stop buttons, gantry control panels, external laser alignment lights, etc. FIG. 2 is a block diagram of an X-ray imaging system according to some embodiments of the present disclosure. It should be noted that X-ray imaging system described below is merely provided for illustrating an example of the radiation imaging system, and not intended to limit the scope of the present disclosure. The radiation used herein may include a particle ray, a photon ray, or the like, or any combination thereof. The particle ray may include neutron, proton, electron, μ-meson, heavy ion, or the like, or any combination thereof. The photon beam may include X-ray, γ-ray, α-ray, β-ray, ultraviolet, laser, or the like, or any combination thereof. For better understanding the present disclosure, an X-ray imaging system is described as an example of a radiation imaging system. The X-ray imaging system may find its applications in different fields such as medicine or industry. In some embodiments of medical diagnosis, the X-ray imaging system may be a Computed Tomography (CT) system, a Digital Radiography (DR) system or may be used in some other multi-modality system, e.g., a Computed Tomography-Positron Emission Tomography (CT-PET) system, a Computed Tomography-Magnetic Resonance Imaging (CT-MRI) system. In some embodiments of industrial application, the system may be used in internal inspection of components e.g., flaw detection, security scanning, failure analysis, metrology, assembly analysis, void analysis, wall thickness analysis, or the like, or any combination thereof. As illustrated in FIG. 2, an X-ray imaging system may include, an X-ray imaging scanner 210, a control module 220, a processing module 230, and a terminal 240. The X-ray imaging scanner may include an X-ray generator and an X-ray detecting unit (see, for example, FIGS. 4 and 6). In some embodiments, the X-ray imaging scanner may include other components including, e.g., a gantry, a grid, a support table, etc. The control module 220 may control the X-ray imaging scanner 210, the processing module 230, and/or the terminal 240. The processing module 230 may process information received from the X-ray imaging scanner 210, the control module 220, and/or the terminal 240, and generate one or more CT images based on the information and deliver the images to the terminal 240. The terminal 240 may be configured or used to receive input and/or display output information. The X-ray imaging scanner 210, the control module 220, the processing module 230, and the terminal 240 may be connected with each other directly, or with an intermediate module (not shown in FIG. 2). The intermediate module may be a visible component or an invisible field (radio, optical, sonic, electromagnetic induction, etc.). The connection between different modules may be wired or wireless. The wired connection may include using a metal cable, an optical cable, a hybrid cable, an interface, or the like, or any combination thereof. The wireless connection may include using a Local Area Network (LAN), a Wide Area Network (WAN), a Bluetooth, a ZigBee, a Near Field Communication (NFC), or the like, or any combination thereof. It should be noted that the above description about the radiation system is merely an example. Obviously, to those skilled in the art, after understanding the basic principles of the connection between different modules, the modules and connection between the modules may be modified or varied without departing from the principles. The modifications and variations are still within the scope of the present disclosure described above. In some embodiments, these modules may be independent, and in some embodiments, part of the modules may be integrated into one module to work together. The X-ray imaging scanner 210 may be configured or used to scan an object (not shown in FIG. 2) under examination and generate the source data of an X-ray image. The object may be a substance, a tissue, an organ, an object, a specimen, a body, or the like, or any combination thereof. In some embodiments, the object may include a head, a breast, a lung, a pleura, a mediastinum, an abdomen, a colon, a small intestine, a bladder, a gallbladder, a triple warmer, a pelvic cavity, a backbone, extremities, a skeleton, a blood vessel, or the like, or any combination thereof. The X-ray generating unit may be configured or used to generate X-rays to traverse the object under examination. The X-ray generating unit may include an X-ray generator, a high-voltage tank, and/or one or more other accessories. Additionally, the X-ray generator may include one or more X-ray tubes which may emit X-rays by an X-ray tube. Moreover, the X-ray generating unit may be a cold cathode ion tube, a high vacuum hot cathode tube, a rotating anode tube, etc. The shape of the X-ray beam emitted may be a line, a narrow pencil, a narrow fan, a fan, a cone, a wedge, or the like, or an irregular shape, or any combination thereof. The X-ray tube in the X-ray generating unit may be fixed at a point and it may translate or rotate in some scenarios. In some embodiments, the focal spot of the X-ray beam may be in a fixed position inside the X-ray generator. In some embodiments, the focal spot of the X-ray beam may be movable inside the X-ray generator, and the trajectory of the focal spot may be continuous or discrete. In some embodiments, the continuous trajectory may be a line, a sine curve, a sawtooth wave, or other regular or other irregular shape. In some embodiments, for the discrete trajectory, the number of the positions of the focal spot may be an arbitrary value, e.g., two, three, four, five. The positions may be in a line, in a plane or in a 3D space. In some embodiments, the interval between each two positions may be equivalent or not. The X-ray detecting unit may be configured to receive the X-rays emitted from the X-ray generating unit or other radiation source. The X-ray beams from the X-ray generating unit may traverse the object under examination. After receiving the X-rays, the X-ray detecting unit may generate the source data of an X-ray image of the object under examination. The term “source data” may refer to the data that may be detected by the X-ray detecting unit, and/or that may be transformed to the image data according to an imaging processing procedure based on, for example, an algorithm. As used herein, the term “image data” may refer to the data that may be used to construct an image. The X-ray detecting unit may be configured to receive X-rays and generate the source data of an X-ray image of the object under examination. The X-ray detecting unit may include an X-ray detector, and/or one or more other components. The shape of the X-ray detector may be flat, arc-shaped, circular, or the like, or any combination thereof. The fan angle of an arc-shaped detector may be an angle from 0° to 360°. The fan angle may be fixed or adjustable according to different conditions including, for example, the desired resolution of an image, the size of an image, the sensitivity of a detector, the stability of a detector, or the like, or any combination thereof. In some embodiments, the X-ray detector may be one-dimensional, two-dimensional, or three-dimensional. In some embodiments, there may be a collimator located or placed between the X-ray generating unit and an object (or referred to as a target). In some embodiments, there may be one or more grids between the target and the detecting unit. The grids may be configured to absorb and/or block the scattered radiation from the object under examination. The number of the grids may be one, two, three, or any other value. In some embodiments, the grids may physically contact or be in direct contact with each other. In some embodiments, the grids may be spaced apart from each other. In some embodiments, a grid and a detector may physically contact or be in direct contact with each other or be spaced apart from each other. In some embodiments, the grids may be parallel to a detector. In some embodiments, the grids may be placed at an angle to the detector. The angle may be adjustable from 0° to 360°. In some embodiments, the grids may be parallel to one or more other grids. In some embodiments, the grids may be placed with an adjustable angle from 0° to 360° with each other. It should be noted that the above description about the X-ray image unit is merely an example according to the present disclosure. Obviously, to those skilled in the art, after understanding the basic principles of the X-ray image unit, the form and details of the X-ray image unit may be modified or varied without departing from the principles. The modifications and variations are still within the scope of the present disclosure described above. The control module 220 may be configured to control the X-ray imaging scanner 210, the processing module 230, the terminal 240, or one or more other units or devices in the system according to some embodiments of the present disclosure. The control module 220 may communicate with (by way of, for example, receiving information from and/or sending information to) the X-ray imaging scanner 210, the processing module 230, and/or the terminal 240. In some embodiments, the control module 220 may provide a certain voltage, and/or certain current to the X-ray imaging scanner 210 for scanning. The voltage and/or current may be different for different targets including, for example, people of different age, weight, height, etc. In some embodiments, the control module 220 may control the position of the focal spot of an X-ray beam, the motion speed of the focal spot, the position of one or more grids, or the like, or any combination thereof. See, for example, FIG. 4 and the description thereof. In some embodiments, the control module 220 may receive a command from the terminal 240 provided by, e.g., a user. Exemplary commands may include a scanning time, a location of the object to be examined, a rotating speed of the gantry, or the like, or any combination thereof. The control module 220 may control the processing module 230 to select different algorithms to process the source data of an X-ray image. The control module 220 may transmit a command to the terminal 240. Exemplary commands may include the size of an image, the location of an image, or the duration of an X-ray image to be displayed on a display screen. In some embodiments of the present disclosure, the X-ray image may be divided into several sub-portions for display, and the control module 220 may control the number of the sub-portions. It should be noted that the above description about the control unit is merely an example according to the present disclosure. Obviously, to those skilled in the art, after understanding the basic principles of the control unit, the form and details of the control module 220 may be modified or varied without departing from the principles. The modifications and variations are still within the scope of the present disclosure described above. The terminal 240 may be configured or used to receive input and/or display output information. The input and/or output information may include programs, software, algorithms, data, text, number, images, voice, or the like, or any combination thereof. For example, a user or an operator may input an initial parameter or condition to initiate a scan. Exemplary parameters or conditions may include the scanning time, the location of the object for scanning, the rotating speed of the gantry, or the like, or a combination thereof. As another example, some information may be imported from an external source, such as a floppy disk, a hard disk, a USB flash drive, a wireless terminal, or the like, or any combination thereof. The terminal 240 may show the X-ray image of an object from the processing module 230 to the user. The terminal 240 may receive information from the control module 220 to adjust some parameters for displaying. Exemplary parameters may include the size of an image, the location of an image, the time duration of an image remains on a display screen, or the like, or a combination thereof. The terminal 240 may display the whole or part of an X-ray image. In some embodiments, an X-ray image may be divided into several portions, which may be display on a screen at the same time or in a certain order. In some embodiments of the present disclosure, the user or the operator may select one or more portions for display. It should be noted that the above description about the display unit is merely an example according to the present disclosure. Obviously, to those skilled in the art, after understanding the basic principles of the display unit, the form and details of the display unit may be modified or varied without departing from the principles. The modifications and variations are still within the scope of the present disclosure described above. It should be noted that the above description of the X-ray imaging system is merely provided for the purposes of illustration, and not intended to limit the scope of the present disclosure. For persons having ordinary skills in the art, multiple variations and modifications may be made under the teachings of the present disclosure. For example, the assembly and/or function of the X-ray imaging system may be varied or changed according to specific implementation scenarios. Merely by way of example, some other components may be added into the X-ray imaging system, such as a patient positioning unit, a high-voltage tank, an amplifier unit, a storage unit, an analog-to-digital converter, a digital-to-analog converter, an interface circuit, or the like, or any combination thereof. Note that the X-ray imaging system may be a traditional or a single-modality system, or a multi-modality system including, e.g., a Positron Emission Tomography-Computed Tomography (PET-CT) system, a Computed Tomography-Magnetic Resonance Imaging (CT-MRI) system, a remote medical X-ray imaging system, etc. However, those variations and modifications do not depart from the scope of the present disclosure. FIG. 3 depicts a flowchart illustrating the process of an X-ray scanning according to some embodiments of the present disclosure. It should be noted that X-ray scanning process described below is merely provided for illustrating an example of the radiation imaging, and not intended to limit the scope of the present disclosure. As illustrated in FIG. 3, in step 301, X-ray beams may be generated. X-ray beams may be generated by the X-ray generating unit, or another radiation source. In some embodiments, an X-ray tube in the X-ray generating unit may emit X-ray beams forming the shape of a line, a narrow pencil, a narrow fan, a fan, a cone, a wedge, or the like, or an irregular shape, or any combination thereof. The fan angle of the X-ray beams may be a certain value within the range from 0° to 360°. In some embodiments, before step 301, there may be some parameters to be set by a user or an operator. Exemplary parameters may include the parameters for the gantry, for the X-ray tube, for the X-ray detector, for a display device, or for one or more other devices or units in or communicated with the system. Merely by way of example, a user may set parameters including a certain voltage, and/or a certain current for people of a certain age, weight, height, etc. In some embodiments, the gantry may be adjusted to a certain rotating speed according to some parameters. In some embodiments, the beam shape and the angle of a fan beam may be selected based on one or more parameters. The type of the X-ray detector may be selectable based on one or more parameters. It should be noted that the above description about the parameters is merely provided for the purposes of illustration, and not intended to limit the scope of the present disclosure. For persons having ordinary skills in the art, multiple variations and modifications about the parameters that are set may be made under the teachings of the present disclosure. In step 302, the X-ray imaging scanner may be configured. In some embodiments, before scanning an object, noise in the system may be measured. In some embodiments, there may be one or more parameters to be adjusted according to a condition including, for example, a spatial resolution, sensitivity, stability, or the like, or any combination thereof. Exemplary parameters may include the position of the focal spot of the X-ray beam, the motion speed of the focal spot, the position of the grids, or the like, or any combination thereof. In some embodiments, the spatial resolution may be adjusted or improved for a certain object (for example, a certain organ) than others. This may be achieved by, for example, decreasing the area for receiving radiation in a pixel of an X-ray detector (e.g., a detector cell), referred to as an active area of a pixel (for example, a detector cell). In some embodiments, the active area may be adjusted by way of adjusting, for example, the position of the focal spot of the X-ray beam, the position(s) of the grid(s), the distance of a grid from the X-ray source, the angle formed by a grid and an X-ray detector, the angle formed by two grids, the position of a grid relative to another grid, or the like, or any combination thereof. It should be noted that the step 301 and step 302 described herein is merely an example, and not intended to limit the scope of the present disclosure. For persons having ordinary skills in the art, multiple variations and modifications in the form and structure may be made under the teaching of the present disclosure. For example, the order of the steps may be reversed, i.e., the X-ray imaging scanner may be configured first, and the focal spot of the X-ray beam and the grids may be adjusted to the proper positions and then, the X-rays may be generated. In step 303, the X-ray beams may be received by, for example, the X-ray detecting unit of the X-ray imaging scanner 210. In some embodiments, the X-ray detector of the X-ray detecting unit may receive X-ray beams impinging thereon. The impinging X-ray beams may include the X-ray beams that have traversed an object under examination, the X-ray beams directly emitted from the X-ray generating unit, and/or the X-ray beams from one or more other radiation sources. Parts of the X-ray beams emitted from the X-ray generating unit may be blocked and/or absorbed by one or more grids located before the X-ray detector. In some embodiments, the X-ray beams may first be converted to light energy by, for example, a scintillator, and then an electrical signal may be produced therefrom by, for example, a photodiode. The electrical signal may be transmitted to, for example, the processing module 230. It should be noted that the above description about the signal conversion is merely provided for the purposes of illustration, and not intended to limit the scope of the present disclosure. For persons having ordinary skills in the art, multiple variations and modifications in the form and structure may be made under the teaching of the present disclosure. For example, the scintillators may be replaced by other components that may absorb the radiation and generate light energy, and the photodiodes may be replaced by other components which may be capable of converting the light energy to electrical signals. The received signals may be processed in step 304. In some embodiments, the processing module 230 may process the data from the X-ray detector to generate the X-ray image data of an object under examination. The process may involve an algorithm including, for example, a filtered back projection, an n-PI, a tomosynthesis, or the like, or a combination thereof. In this step, the image may be calibrated using a calibration algorithm. In some embodiments, the image data, the calibrated data, and/or the received signals from the processing module 230 may be stored in a storage unit and/or device. A storage unit or device may store information by the way of electric, magnetic, or optical energy, etc. The device that store information by the way of electric energy may include Random Access Memory (RAM), Read Only Memory (ROM), or the like, or any combination thereof. The device that stores information by the way of magnetic energy may include a hard disk, a floppy disk, a magnetic tape, a magnetic core memory, a bubble memory, a USB flash drive, or the like, or any combination thereof. The device that store information by the way of optical energy may include CD (Compact Disk), VCD (Video Compact Disk), or the like, or any combination thereof. The method to store information may include sequential storage, link storage, hash storage, index storage, or the like, or any combination thereof. The image data or the calibrated image may be shown to the user or operator via the terminal 240. In some embodiments, the X-ray image of the object may be printed. In some embodiments, the calibrated or uncalibrated image data of the object may be transmitted to a third party including, for example, a doctor. The doctor may make an assessment or decision based on the data received. It should be noted that the above description about the process of X-ray scanning is merely an example according to the present disclosure. Obviously, to those skilled in the art, after understanding the basic principles of the process of X-ray scanning, the form and details of the process may be modified or varied without departing from the principles. In some embodiments, other steps may added in the process. For example, the results of the processing may be displayed on some devices, and the intermediated data and/or the final data of the process may be stored in the process. The modifications and variations are still within the scope of the present disclosure described above. FIG. 4 is an exemplary schematic diagram of the CT scanning system according to some embodiments of the present disclosure. As described elsewhere in the disclosure, the control module 220 may be configured to control the X-ray imaging scanner 210 in order to generate data for further processing by the processing module 230. During the operation of the scanning, different parts of the X-ray imaging scanner 210 may be controlled separately by respective controllers. As shown in FIG. 4, the control module 220 may include an X-ray controller 410, a gantry controller 420, and a grid controller 430. The X-ray controller 410 may provide power and timing signals to an X-ray source 108. In some embodiments, the X-ray source 108 may include more than one focal point, in which case the radiation received by the detector 107 may come from different focal spots that a number of beam paths are produced during scanning. Thus, the one or more focal spots generating the X-ray may be controlled by the X-ray controller 410 under certain conditions in the scanning. During a scanning to acquire X-ray projection data, the gantry and the components mounted thereon may rotate about a center of rotation. The rotational speed and position of the gantry 101 may be controlled by the gantry controller 420. In the gantry, the X-ray source 108 may project an X-ray beam toward a detector 107 or a collimator on the opposite side of the gantry. In some embodiments, the detector 107 may be formed by a plurality of detector cells and a data acquisition system (not shown in FIG. 4). The plurality of detector cells may sense the projected X-rays that pass through a subject, and the data acquisition system may convert the data to digital or analog signals for subsequent processing. A detector cell may produce a signal that may represent the intensity of an impinging X-ray beam. If an X-ray beam passes through the subject before reaching the detector cell, the intensity of the impinging X-ray beam may be attenuated. In some embodiments, the working condition of a detector cell may be controlled by the gantry controller 420. In some embodiments, the gantry controller 420 may control or adjust the sensitivity of a detector cell. For example, the gantry controller 420 may be configured to adjust the detector cell(s) to provide a higher sensitivity when scanning a structure/tissue of a small dimension. In another example, the sensitivity may be adjusted when the X-ray beam is blocked or partially blocked by, for example, a grid. As used herein, the sensitivity of a detector cell may represent the ability to detect a radiation signal with certain intensity. The sensitivity of a detector cell may be related to, for example, the voltage applied on the detector cell, the temperature of the detector cell, the material of the detector cell, or the like, or a combination thereof. One or more grids may be arranged or located between the X-ray source 108 and the detector 107 in order to change the detection of radiation in some manner. In some embodiments, the grids may be controlled along with the detector 107. In some embodiments, one or more grids may be controlled in relation with the focal points of the X-ray source 108. For instance, different focal spots may be applied along with different grid arrangements. The grid arrangement may be controlled by the grid controller 430. Exemplary grid arrangements may include changing the number of grids, selecting or replacing the types of grids, adjusting the movement of one or more grids, or the like, or a combination thereof. Changing the number of grids may include increasing or decreasing grids used in the scanning. Considering that different configurations of the grids may result in different scanning effect, the type of the grids may be selected or replaced in some situations. As used herein, the type of a grid may correspond or relate to the dimension of a radiation transmitting section, the shape of a radiation transmitting section, the thickness of the grid, the material(s) of the grid, or the like, or a combination thereof. A grid may include a plurality of radiation transmitting sections, or referred to as radiation transmitting portions. The dimension of radiation transmitting sections (or radiation transmitting sections) of a grid may affect the spatial resolution. As used herein, the radiation transmitting section or radiation transmitting portion may refer to the area on a grid that radiation may not be absorbed or blocked. For instance, the radiation transmitting section or radiation transmitting portion may be an opening or slit on the grid through which a radiation beam may pass through without being absorbed or blocked. The radiation transmitting section or portion may have a shape of a circle, a square, a rectangle, or any shape that is regular or irregular. The dimension of the radiation transmitting sections may represent the width, length, radius, or area, of the radiation transmitting sections. The radiation transmitting section (or portion) may have a characteristic dimension. As used herein, the characteristic dimension of the radiation transmitting section (or portion) may be the smallest dimension of the radiation transmitting section (or portion) among its dimensions including, for example, the length, the width, the radius, etc. Merely by way of example, for a circular radiation transmitting section (or portion), the characteristic dimension is the radius of the radiation transmitting section (or portion). As another example, a square radiation transmitting section (or portion), the characteristic dimension is the length of an edge of the radiation transmitting section (or portion). As a further example, a rectangular radiation transmitting section (or portion), the characteristic dimension is the length of the shorter edge of the radiation transmitting section (or portion). As still a further example, for a radiation transmitting section (or portion) of an irregular shape, the characteristic dimension is the smallest dimension among the one or more dimensions describing or defining the shape of the radiation transmitting section (or portion). The characteristic dimension of a radiation transmitting section may be several orders higher than the wavelength of the radiation. For instance, the characteristic dimension of a transmitting section may be at least 10∧5 times, or at least 10∧6 times, or at least 10∧7 times, or at least 10∧8 times, or at least 10∧9 times, or at least 10∧10 times, or at least 10∧11 times of the wavelength of the radiation used in an imaging system. The characteristic dimension of a radiation transmitting section may be comparable to the dimension of a detector cell. For instance, assuming the dimension of a detector is 1 mm, the characteristic dimension of a radiation transmitting section may be 0.1 mm, or 0.2 mm, or 0.3 mm, or 0.4 mm, or 0.5 mm, or 0.6 mm, or 0.8 mm. The grid may include one or more radiation absorbing sections, or referred to as radiation absorbing portions. As used herein, the radiation absorbing section or radiation absorbing portion may refer to the area on a grid that radiation may be absorbed or blocked. For instance, radiation impinging on a radiation absorbing section or radiation absorbing portion may not pass through the grid. In some embodiments, the radiation transmitting sections may be adjusted using a shielding device. The shielding device may be coupled to the grid. The shielding device may be a radiation blocker or absorber set in/on the grid, or coupled without contacting the grid. The shielding device may be made of lead, gold, tungsten, depleted uranium, thorium, barium sulfate, tantalum, iridium, osmium, or the like, or any combination thereof. The configuration of the shielding device may be in the form of a slip sheet, a shutter, a rotation blade, or the like, or a combination thereof. Merely by way of example, a grid may include a plurality of radiation transmitting sections; a shielding device may include multiple rotation blades; each of at least some of the radiation transmitting sections may be associated with a rotation blade of the shielding device; the radiation transmitting sections of the grid with associated rotation blades may be adjusted by rotating the rotation blades such that the areas of these radiation transmitting sections allowing the passage of radiation may be adjusted. In some embodiments, the shielding device is not attached to or does not otherwise contact the grid. In some embodiments, a shielding device may be movably attached to a grid. As used herein, a movable attachment may indicate that the shielding device, or a portion thereof, may move relative to the grid to which the shielding device attaches. For instance, a shielding device may include a plurality of shutters; the shutters may be movably attached to the grid. The shielding device, or a portion thereof, may at least partially cover a radiation transmitting section or portion. The coverage may be adjusted so that the open area of the radiation transmitting section or portion that may allow passage of radiation may be adjusted. The coverage may range from no coverage to full coverage. As indicated herein, no coverage may indicate that the entire radiation transmitting section or portion is available to allow passage of radiation. As indicated herein, full coverage may indicate that the entire radiation transmitting section or portion is covered by a shielding device or a portion thereof (for example, a shutter of the shielding device), and therefore no portion of the radiation transmitting section or portion is available to allow passage of radiation. The movement of a grid may lead to the movement of the radiation transmitting sections on the grid. Merely by way of example, the movement of a grid may include a motion along a certain direction (e.g., the Z-direction, or any direction on the x-y plane), a tilting with respect to a certain axis, or the like, or a combination thereof. The motion of the grid along a certain direction may cause the motion of the radiation transmitting sections on the grid, and the active area of a detector cell may also change. The tilting of a grid may also lead to a change of the active area of a detector cell. As used herein, the active area of a detector cell may refer to the area that receives radiation transmitted through the object and/or the grid(s) detectable by the detector cell. In some embodiments, an active area of a detector cell may relate to the spatial resolution of the imaging system. For instance, a small active area of a detector cell may correspond to higher spatial resolution of the scanning system. In some embodiments, an active area of a detector may relate to the resolution of a reconstructed image. For instance, the smaller active area of a detector may correspond to higher resolution of a reconstructed image. The X-ray controller 410, the gantry controller 420, and the grid controller 430 may be configured to operate systematically. Put another way, the operation of an X-ray source (e.g., the focal points), the operation of the gantry (e.g., the rotation), and the arrangement of the one or more grids (e.g., the motion, the rotation) may be operatively coupled with each other to provide, for example, a desired spatial resolution for subsequent processing. For example, the operation of an X-ray source, the operation of the gantry, and the arrangement of the one or more grids may be conducted in a coordinated way to achieve an adjustable spatial resolution. In some embodiments, one of the operation of an X-ray source, the operation of the gantry, and the arrangement of the one or more grids may be selectively conducted to change the spatial resolution. Merely by way of example, a radiation-based imaging system may include two grids, a first grid and a second grid, a radiation source (for example, an X-ray source), and a detector. The detector may include a plurality of detector cells. The two grids may be located between the radiation source and the detector. The spatial resolution of the system may be adjusted by adjusting the active areas of detector cells of the detector. The adjustment may be achieved by adjusting a radiation transmitting portion of one grid and/or a radiation transmitting section of the other grid to change the area that may allow radiation to pass through. For a radiation beam to pass through both grids, the radiation beam may need to pass through an area (referred to as an overlapping area) where a radiation transmitting portion of one grid and/or a radiation transmitting section of the other grid overlap along the path of the radiation beam. For instance, the adjustment may be achieved by adjusting the overlapping area by moving one or both grids, or tilting one or both grids. Two or more way for adjustment may be combined. As another example, the imaging system may include a grid. The spatial resolution of the system, or the active areas of detector cells of the detector, may be adjusted by adjusting the area of a radiation transmitting portion or section that may allow radiation to pass through. For instance, the adjustment may be achieved by tilting a grid by an angle, or moving the position of the grid. As a further example, the imaging system may include a shielding device. The shielding device may be configured to block at least part of the radiation from the radiation source. The spatial resolution of the imaging system may be adjusted by adjusting the shielding device. The amount of the radiation blocked may be adjusted by adjusting the shielding device. In some embodiments, the shielding device may be a radiation blocker or absorber set in/on the grid, or coupled without contacting the grid. The shielding device may be made of lead, gold, tungsten, depleted uranium, thorium, barium sulfate, tantalum, iridium, osmium, or the like, or any combination thereof. The configuration of the shielding device may be in the form of a slip sheet, a shutter, a rotation blade, or the like, or a combination thereof. See relevant description regarding the shielding device elsewhere in the present disclosure. One or more of the ways for adjusting the spatial resolution of the imaging system may be used alone, or in combination. For example, the adjustment of the position of the grid and the adjustment of the shielding device on the grid may be used cooperatively to achieve a desired spatial resolution. It should be noted that the description of the CT scanning system is provided for the purposes of illustration, and not intended to limit the scope of the present disclosure. For persons having ordinary skills in the art, various variations and modifications may be conduct under the teaching of the present disclosure. However, those variations and modifications may not depart from the protecting of the present disclosure. For example, the effect of the X-ray controller 410, the gantry controller 420, and/or the grid controller may be achieved by a single integrated controller. Additionally, the controllers may communicate with each other through a wired connection, or the communication may also be realized in a wireless way. FIG. 5 is an exemplary flowchart of an exemplary process for CT scanning according to some embodiments of the present disclosure. At step 501, the CT scanner may be initialized. During the initialization, a plurality of parameters may be set. Exemplary parameters to be initialized may include, for example, the parameters relating to the X-ray source, the parameters relating to the detector, the parameters relating to the detector cells, the parameters relating to the gantry and components mounted thereon, the parameters relating to the grids, the parameters relating to the reconstruction process, or the like, or a combination thereof. The parameters relating to the X-ray source may include the shape of the X-ray beams including, for example, a line, a narrow pencil, a narrow fan, a cone, a wedge, an irregular shape, or the like, or a combination thereof, emitted by the X-ray tube. In some embodiments, a plurality of focal spots may be configured to emit the X-rays in the X-ray source. The size and/or position of the focal spots may be initialized to for subsequent processing. The CT scanner may also include a shielding device configured to adjustably block the radiation from the X-ray source. The parameters relating to the detector may include the shape of the detector including, e.g., flat, arc-shaped, circular, etc. The parameters relating to the detector cells may include the size and/or the sensitivity of the cell. The parameters relating to the gantry and components mounted thereon may include the rotational speed of the gantry. The parameters relating to the grids may include the arrangement of the grids, such as, the number of the grids. The parameters relating to the reconstruction process may include the shape and/or size of voxels, the algorithm for calculating the values of respective voxels, the algorithm for reconstructing an image data (e.g., iterative projection, filtered back projection, etc.), or the like, or a combination thereof. A spatial resolution of the scanning system may be assessed at step 502. If a desired spatial resolution is satisfied, an object may be scanned in step 506. If the desired spatial resolution is not satisfied, one or more parameters may be adjusted, Merely by way of example, in order to achieve higher spatial resolution in the scanning system, at steps 503, 504, and 505, the size and/or position of the focal spots may be adjusted, the shielding device, and/or the first grid and/or the second grid (if applicable) may be adjusted. The adjustment may be such that the amount and/or distribution of radiation impinging on detector cells of the detector are changed to provide the desired spatial resolution. The active area of a detector cell may receive radiation from a radiation source that passes through at least one of a plurality of radiation transmitting sections or portions of a grid. See relevant description elsewhere in the present disclosure. Various adjustments may be such that active areas of detector cells are changed to provide the desired spatial resolution. For instance, if a grid is used, the adjustment may be achieved by adjusting the area of a radiation transmitting portion or section that may allow radiation to pass through. For instance, the adjustment may be achieved by tilting a grid by an angle, or moving the position of the grid. If a plurality of grids are used, the adjustment may be achieved by adjusting a radiation transmitting portion of one grid and/or a radiation transmitting section of the other grid to change the area that may allow radiation to pass through. For a radiation beam to pass through both grids, the radiation beam may need to pass through an area where a radiation transmitting portion of one grid and/or a radiation transmitting section of the other grid overlap along the path of the radiation beam. For instance, the adjustment may be achieved by adjusting the overlapping area by moving one or both grids, or tilting one or both grids, Two or more ways for adjustment may be combined. For instance, the adjustment of the shielding device may be combined with the adjustment of one or more grids to achieve a desired spatial resolution. Merely by way of example, two grids are included. The adjustment of the first and/or the second grids may include arranging the positions of the first grid and/or the second grid. For example, the first grid may be arranged to move along a first direction, and/or the second grid may be arranged to move along a second direction. The first direction may be parallel, or perpendicular to, or at an oblique angle with the second direction. For instance, the angle between the first direction and the second direction may be any degrees, e.g., 10°, 15°, 20°, 25°, 30°, 40°, 45°, 60°, 75°, or the like. In another example, the first grid may be arranged to tilt about an axis by a certain angle, and/or the second grid may be arranged to move along a certain direction. In a further example, the first grid may be arranged to tilt about an axis by a first angle, and/or the second grid may be arranged to tilt about another axis by a second angle. As used herein, the first direction/angel may be either the same as or different from the second direction/angel. In some embodiments, the extending direction of the radiation transmitting sections on the first grid and the second grid may be different. For example, the extending direction of the radiation transmitting sections on the first grid may be perpendicular to the extending direction of the radiation transmitting sections on the second grid. In some embodiments, the term “radiation transmitting section” may be used in association with the first grid, and the term “radiation transmitting portion” may be used in association with the second grid. In some embodiments, the first grid may be arranged to move along the direction perpendicular to the extending direction of the radiation transmitting sections on the first grid (e.g., X-direction, or Y-direction), and the second grid may be arranged to move along the direction perpendicular to the extending direction of the radiation transmitting sections on the second grid (e.g., Z-direction). In some embodiments, the adjustment of the focal point, the first grid, and the second grid may be operatively coupled with each other. For example, the position of the focal spot may be represented by function ƒ(x, y, z), the position of the first grid may be represented by function ƒ1(x1, y1, z1), and the position of the second grid may be represented by function ƒ2(x2, y2, z2). By controlling the position of the focal point, the position of the first grid, and the position of the second grid, the active area on a respective detector cell may be adjusted, which may result in a specific spatial resolution. The adjustment may be expressed asQ(S,P)=Control[ƒ(x,y,z),ƒ1(x1,y1,z1),ƒ2(x2,y2,z2)], (1) where Q(S, P) is the controlling process, Control is the controlling method. The detailed descriptions about the adjustment may be found elsewhere in the present disclosure. An object may be scanned at step 506. Another assessment may be conducted at step 507. If another adjustment is needed, parameters of interest, such as, the position of the focal points, the parameters relating to the first and/or the second grid may be adjusted. If no adjustment is needed, image reconstruction may be performed at step 508. Merely by way of examples, a plurality of iterations may be performed during the reconstruction, such that during each of the iterations, a reconstructed image may be generated. When a termination criterion is satisfied, for example, the difference between the reconstructed image from the current iteration and the preceding iteration is below a certain threshold, the iteration may terminate. A reconstructed image may be proceeded to perform image correction at step 509. During the image correction, the noise in the reconstructed image may be further reduced. Moreover, step 508 may also include a process to enhance the contrast of the reconstructed image. It should be noted that the description of the scanning system is provided for the purposes of illustration, and not intended to limit the scope of the present disclosure. For persons having ordinary skills in the art, various variations and modifications may be conduct under the teaching of the present disclosure. However, those variations and modifications may not depart from the protecting of the present disclosure. For example, the initialization may be performed by executing instructions stored in a storage unit, or a user may control the initialization and set the parameters manually. The working condition and/or sensitivity of detector cells may also be taken in account when the scanning system is initialized and/or the parameters of interest is adjusted. FIG. 6 is a 3D schematic of an X-ray imaging scanner with two grids set before the X-ray detector. It should be noted that the configuration described in the figure is merely for exemplary purposes, and is not intended to be limiting. As shown in FIG. 6, an X-ray generating unit 601 may emit radiation toward, for example, an object 602, a grid (for example, a first grid 603, a second grid 604, etc.), an X-ray detector 605, or the like, or a combination thereof. The radiation traversing the object 602 may be detected by the X-ray detector 605. Because of the first grid 603 and the second grid 604 located between the object 602 and the X-ray detector 605, part of the radiation may be blocked and/or absorbed. The shape of the X-ray beams emitted by the X-ray generating unit 601 may be a line, a narrow pencil, a narrow fan, a fan, a cone, a wedge, or the like, or an irregular shape, or any combination thereof. The X-ray generating unit 601 may include a focal spot where the radiation is emitted. In some embodiments, the focal spot of the radiation including, for example, X-ray beams, may be at a fixed position inside the X-ray generator or the X-ray generating unit 601. In some embodiments, the focal spot of the radiation including, for example, X-ray beams, may be movable inside the X-ray generator or the X-ray generating unit 601. The trajectory of the focal spot may be continuous or discrete. In some embodiments, the continuous trajectory may be a line, a sine curve, a sawtooth wave, or other regular or other irregular shape. In some embodiments, for the discrete trajectory, the number of the positions of the focal spot may be, for example, two, three, four, five, or more. The positions may be in a line, in a plane, or in a three-dimensional (3D) space. In some embodiments, the interval between each two positions may be equivalent or not. In some embodiments, the shape formed by these positions may be a triangle, isosceles or not. In some embodiments, the shape formed by these positions may be a quadrangle, including, a rectangle, a diamond, or any shapes with four edges. In some embodiments, the shape formed by these positions may be a circular, an ellipse. In some other embodiments, the shape formed by these positions may be a three dimensional figure, including a solid, a sphere, or any shapes regular or irregular. The speed and the movement of the focal spot may be controlled by the X-ray controller 410 according to the demands including, the spatial resolution, the position of the grids set in the system, or the like, or a combination thereof. The X-ray controller 410 may supply a control parameter to the X-ray generating unit, including, a voltage, a current, an electric field, a magnetic field, or the like, or any combination thereof. In some embodiments, the control parameter may be constant or variable. In some embodiments, the variation may be continuous or a step change, and the step may be equal or unequal. With the movement of the focal spot of the X-ray beam, the active area of receiving radiation for a detector cell of an X-ray detector may be changed. In some embodiments, the active area of receiving radiation for each detector cell may be changed. In some embodiments, the active area of receiving radiation for part of the detector cells may be changed. As shown in FIG. 6, the first grid 603 and the second grid 604 set between the target 602 and the X-ray detector 605 may be configured to block and/or absorb some radiation traversing the target 602 and the radiations directly from the X-ray generating unit 601. It should be noted that the grids 603 and 604 are merely for exemplary purposes, and is not intended to be limiting. In some embodiments, there may be one or more grids set between the target 602 and the X-ray detector 605. In some embodiments, there may be one or more collimators (not shown in FIG. 6)) set between the X-ray generating unit 601 and the target 602. The shape of the grids may be flat, arc-shaped, circular, or the like, or any combination thereof, and the first grid 603 and the second grid 604 may be the same or different in configuration. As illustrated in FIG. 6, the first grid 603 may include a plurality of radiation absorbing portions 603-A and a plurality of radiation transmitting portions 603-B. The second grid 604 may include a plurality of radiation absorbing portions 604-A and a plurality of radiation transmitting portions 604-B. The first grid 603 may be parallel to the second grid 604. The radiation transmitting portions 603-B may be parallel with each other, extending along the X-direction. The radiation transmitting portions 604-B may also be parallel with each other, extending along the Z-direction. As described elsewhere in the disclosure, at least one shielding device may be used in combination with the first grid 603 and/or the second grid 604 so as to adjustably block the radiation from the X-ray source. The shielding device may be arranged in different manners. For example, the shielding device may be placed between the detector and the grid. For another example, the shielding device may be placed between the detector and the second grid 604. For still another example, the shielding device may be placed between the first grid 603 and the second grid 604. In a further example, a plurality of shielding devices may be placed in different positions with respect to different grids. Embodiments of the shielding device are illustrated in FIG. 13-A and FIG. 13-B and the description thereof. It should be noted that the above description about the grids is merely an example, and not intended to limit the scope of the present disclosure. For persons having ordinary skills in the art, multiple variations and modifications may be made under the teachings of the present disclosure. For example, the shape of the radiation transmitting portions 603-B and/or the radiation transmitting portions 604-B may be regular or irregular. In some embodiments, the radiation transmitting portions 603-B and/or the radiation transmitting portions 604-B may be uniform in shape. In some other embodiments, a first part of the radiation transmitting portions 603-B and/or the radiation transmitting portions 604-B is same in shape, a second part of the radiation transmitting portions 603-B and/or the radiation transmitting portions 604-B is in a shape different from those of the first part. The width and the length of the radiation transmitting portions 603-B and/or the radiation transmitting portions 604-B may be arbitrary. In some embodiments, the grid pitch of the radiation transmitting portions 603-B and the radiation transmitting portions 604-B may be the same or different. For either grid, the pitches of the radiation transmitting portions may be uniform, or partially uniform, or non-uniform. The radiation absorbing portions 603-A and/or 604-A may be formed with highly absorbing material with large density or heavy nuclei atoms. In some embodiments, the absorbing material of the radiation absorbing portions 603-A may be same with the material of the radiation absorbing portions 604-A. In some embodiments, the absorbing material of the radiation absorbing portions 603-A may be different from the material of the radiation absorbing portions 604-A. Merely by way of example, the absorbing materials may be lead, gold, tungsten, depleted uranium, thorium, barium sulfate, tantalum, iridium, osmium, or the like, or any combination thereof. The radiation transmitting portions 603-B and 604-B may include any material whose absorbability is smaller than the absorbing materials. The radiation transmitting portions 603-B and 604-B may be filled with materials including gas, inorganic material, organic material, or the like, or any combination thereof. For example, the gas may include oxygen, nitrogen, carbon dioxide, hydrogen, air, or the like, or any combination thereof. Exemplary inorganic material may include silicon, carbon fiber, glass, etc. Exemplary organic material may include plastic, rubber, etc. In some embodiments, the material of the radiation transmitting portion 603-B may be same with the material of the radiation transmitting portion 604-B. In some other embodiments, the material of the radiation transmitting portion 603-B may be different from the material of the radiation transmitting portion 604-B. Note that the above embodiments are purely provided for illustration, the present disclosure is not limited to these embodiments. Persons having ordinary skills in the art may make some variations, deformations and/or modifications without any creativity according to the present disclosure. In some embodiments, the grids 603 and 604 may also be incorporated with some components such as electrodes. The variations, deformations and/or modifications are not departing from the spirits of the present disclosure. The grids 603 and 604 may be controlled to move by the grid controller 430 of the control module 220. The control factor may be a voltage, a current, an electric field, a magnetic field, or the like, or any combination thereof. With the movement of the grids, the active area of receiving radiation for a detector cell of an X-ray detector may be changed. For example, when the first grid 603 moves along the Z-direction when the position of the second grid 604 is fixed, the active area of receiving the radiation on a detector cell along the Z-direction may be changed. For another example, when the second grid 604 moves along the X-direction when the position of the first grid 603 is fixed, the active area of receiving the radiation on a detector cell along the X-direction may be changed. For another example, when the first grid 603 moves along the Z-direction and the second grid 604 moves along the X-direction, the active area of receiving the radiation on a detector cell along the X-direction and Z-direction may both be changed. It should be not that, the above description about the movement of the grids is merely an example, and not intend to be limiting. In some embodiments, the grid 603 and the grid 604 may move along a same direction. The moving distance for the grid 603 and/or the grid 604 may be arbitrary. In some embodiments, the grid 603 and the grid 604 may tilt about a certain axis, such as the x axis, y axis, or z axis. The tilting of the first grid 603 and the second grid 604 may be about the same or different directions. In some other embodiments, there may be only one grid. The tilting and/or movement of the grid may still result in changed active area of receiving radiation on a detector cell. In still some other embodiments, there may be more than two grids. The combinational tilting and/or movement of each grid may also result in changed active area of receiving radiation on a detector cell. When the active area of receiving radiation on a detector cell is changed, the special resolution may be changed. The structure of the grids described above is aimed at a detector cell, but it should be noted that it may also be suitable for a whole detector or part of a whole detector. It should be noted that the above description of the grids and relative motions is merely provided for the purposes of illustration, and not intended to limit the scope of the present disclosure. For persons having ordinary skills in the art, multiple variations and modifications may be made under the teachings of the present disclosure. In some embodiments, the grids may be within a same plane. In some embodiments, the grids may be arranged contacting directly with each other. For example, the grids may be arranged along the X-direction, the Y-direction, or the Z-direction. In some embodiments, the grids may be spaced from each other by a certain distance. In some embodiments, a grid and a detector may attach to each other or be spaced from each other by a certain distance. In some embodiments, the grids may be arranged parallel to a detector. In some embodiments, the grids may be arranged at an angle to the detector, and the angle may be adjustable from 0° to 360°. In some embodiments, the grids may be arranged in parallel with other grids or be arranged at angle to one or more other grids, and the angle may be adjustable from 0° to 360°. FIG. 7 shows a schematic sectional view of the effect of a flying focal spot on the active area of a detector cell. In the figure, the number 701 and 702 may represent two positions of a focal spot of the radiation beam inside an X-ray generating unit, the number 703 may represent a grid including radiation absorbing portions 703-A and a radiation transmitting portion 703-B. The radiation emitted from the points 701 and 702 may project on a detector cell 704 through the radiation transmitting portion 703-B of the grid 703. It should be noted that the structure showed in this figure is merely for the purposes of describing conveniently, and is not intended to be limiting. For persons having ordinary skills in the art, the number of the focal spot and that of the grid may be varied arbitrarily according to some embodiments of the present disclosure, and the relative position of the two focal spot may change according to some embodiments of the present disclosure. As shown in FIG. 7, when the focal spot of the radiation beams is at point 701, the width of the region of receiving the radiation is S1. When the focal spot of the radiation beams moves to point 702 under the control of, for example, the X-ray controller, the width of the region of receiving the radiation is S2 that may be different from the width S1. The difference in S1 and S2 may result in different active areas that may receive the radiation on the detector cell 704. The point 702 may be anywhere different from the point 701. In some embodiments, the point 702 may be on the left side of the point 701, on the right side of the point 701, above the point 701, under the point 701, or the like, or a combination thereof. For persons having ordinary skills in the art, it should be understood that when the point 701 and the point 702 do not coincide exactly, the width S1 and S2 may be different. Beside, when the focal spot of the radiation beams is fixed, the change of the location of the grid 703 may result in a different active area on a detector cell. In some embodiments, the grid 703 may move a distance towards the focal spot 701 or the detector cell 704 according to different demands including, e.g., a desired spatial resolution, the size of the X-ray imaging scanner, the whole size of the detector and the size of a detector cell, or the like, or any combination thereof. There may be other factors that may influence the active area of a detector cell, such as, the width of the radiation transmitting portion 703-B, the thickness of the radiation transmitting portion 703-B, the shape of the radiation transmitting portion 703-B, the distance between the grid 703 and the detector cell 704, the distance between the focal spot of the radiation beam and the grid 703, the angle formed by the grid 703 and the detector cell 704, the shape of the radiation beam, the motion speed of the focal spot and/or the grids, or the like, or any combination thereof. In some embodiments, the shape of sectional view of the radiation transmitting portion 703-B may be trapezoid, taper, triangle, or other shapes such as a handstand T shape. Those skilled in the art should understand that the above embodiments are only utilized to describe the present disclosure. There are many modifications and variations to the present disclosure without departing from the spirits of the present disclosure. For example, there may be two or more grids arranged before the detector cell 704, and the active area of a detector cell 704 may be determined by all the grids arranged. FIG. 8 shows a schematic view of a combination of grids and a detector. The detector 803 may include a plurality of detector cells 802 supported by a substrate 801. In some embodiments, a detector cell may include one or more scintillator element and one or more photodetector element. The scintillator element may include a material that may absorb ionizing radiation and/or emit a fraction of the absorbed energy in the form of light. Any scintillator may include a material with at least one of the following features including, for example, a high detective efficiency, high conversion efficiency, low absorption, a wide linear range, strong resistance to interference, or the like, or a combination thereof. The photodetector element in the present disclosure may be a photoelectric conversion element that may firstly detect an optical signal and then convert the optical signal into an electrical signal including, e.g., an electrical current, an electrical voltage, and/or other electrical phenomena. In some embodiments, the thickness of the detector cell 802 may be varied. The size of the detector cell 802 may be varied one or more conditions including, for example, spatial resolution, sensitivity, stability, the size of the detector or the like, or any combination thereof. The shape of the detector cell 802 may be circular, oval, rectangular, or the like, or any combination thereof. The detector cell may be arranged regularly, or irregularly on the substrate 801. In some embodiments, the working conditions of each detector cell 802 may be controlled independently by the control module 220. The substrate 801 may be a solid substance providing a support for the detector 803. The size of the substrate 801 may be varied according to the size of the detector 803. The thickness of the substrate 801 may be varied arbitrarily and not limited here. The overall shape of the substrate 801 may be planar, arc-shaped, or any other shaped substrate in accordance to the different shapes of the X-ray detector 300. Each part of the substrate 801 may be circular, oval, rectangular, or the like, or any combination thereof. The substrate 801 may be arranged regularly, or irregularly. The substrate 801 may include, for example, a semiconducting material, an electrically insulating material, or the like, or a combination thereof. In some embodiments, the semiconducting material may include an elementary substance or a compound. The elementary substance may include silicon, germanium, carbon, tin, or the like. The compound may include silicon dioxide, silicon nitride, silicon carbide, aluminum oxide, sapphire, germanium, gallium arsenide (GaAs), an alloy of silicon and germanium, indium phosphide (InP), poly (3-hexylthiophene), poly (p-phenylene vinylene), polyacetylene, or the like, or their derivatives, or any combination thereof. In some embodiments, the insulating materials may include glass, porcelain, paper, polymers, plastics, or the like, or any combination thereof. Those skilled in the art should understand that the above embodiments are only utilized to describe the present disclosure. There may be many modifications and variations to the present disclosure without departing form the spirits of the present disclosure. For example, the substrate element may be small chips to minimize the size of the X-ray detector. For another example, the X-ray detector may also be an assembly of scintillator elements, photovoltaic conversion elements, chips and other components. For still another example, the substrate or chip may be omitted in some embodiments. Similar modifications and variations are still within the scope of the present disclosure described above. As shown in FIG. 8, the first grid 603 and the second grid 604 may be arranged in front of the detector 803. The first grid 603 may be parallel to the second grid 604. The radiation transmitting portions 603-B extending along the X-direction on the first grid 603 may be parallel with each other. The radiation transmitting portions 604-B extending along the Z-direction on the second grid 604 may be parallel with each other. It should be noted the above description about the grids is merely an example, and not intended to limit the scope of the present disclosure. For persons having ordinary skills in the art, multiple variations and modifications may be made under the teachings of the present disclosure. In some embodiments, the shape of the radiation transmitting portions 603-B and the radiation transmitting portions 604-B may be regular, e.g., a rectangle, a trapezia, a parallelogram. The width and/or the length of the radiation transmitting portions 603-B and the radiation transmitting portions 604-B may be arbitrary. In some embodiments, the grid pitch of the radiation transmitting portions 603-B and the transmitting portions 604-B may be the same or different. For the first grid and/or the second grid, the grid pitches of the radiation transmitting portions may be uniform, partially uniform, or non-uniform. For example, half of the radiation transmitting portions may have a first grid pitch, and the remaining half of the radiation transmitting portions may have another grid pitch which may be different from the first grid pitch. For still another example, all the distances between two neighbor radiation transmitting portions may be different. In some embodiments, the radiation transmitting portions 603-B may extend in the same direction with the radiation transmitting portions 604-B. In some embodiments, the radiation transmitting portions 603-B may extend in a different direction with the radiation transmitting portions 604-B. For example, the extending direction of the radiation transmitting portions 603-B and the extending direction of the radiation transmitting portions 604-B may be orthogonal. The modifications and variations are still within the scope of the present disclosure described above. In some embodiments, a detector cell may correspond to one or more radiation transmitting portion(s) from a grid. In some embodiments, a detector cell may correspond to one or more radiation transmitting portion(s) from more than one grids. The grid 603 and grid 604 may be controlled to move by the grid controller 430 in the control module 220. The control factor may be a voltage, a current, an electric field, a magnetic field, or the like, or any combination thereof. FIG. 9 is a schematic view of active areas of detector cells on a detector. It should be noted that the arrangement of the detector cells is merely for illustration purposes, and is not intended to be limiting. In some embodiments, the gaps among the detector cells may be filled with some materials to absorbed and/or block the X-rays to prevent the chips from being influenced. As illustrated in the figure, each detector cell 802 may have an active area 901, which may be adjustable according to some considerations including, e.g., the spatial resolution, the system noise, one or more other types of noises, or the like, or a combination thereof. The active area 901 may be determined by, for example, the geometrical relationship of the focal spot of the radiation beam and/or the grids between the target and the detector. The position of the active area 901 may move and/or the scale of the active area 901 may change when the focal spot of the radiation beam moves, and/or the position of the grids changes. It should be noted that the above description of the active area is merely provided for the purposes of illustration, and not intended to limit the scope of the present disclosure. For persons having ordinary skills in the art, multiple variations and modifications may be made under the teachings of the present disclosure. For example, the shape of the active area may be a triangle, quadrangle, including, a rectangle, a diamond, or any shapes with four edges. In some embodiments, the shape formed by these positions may be a circular, an ellipse. In some embodiments, the shape of the active area may be an irregular shape. In some embodiments, there may be several active areas for one detector cell and the active areas may have a same, or different, shape(s). For example, there may be two or more rectangular active areas for a detector cell. In some embodiments, the position of the active areas may be anywhere of a detector cell. FIG. 10-A and FIG. 10-B are schematic diagrams showing an exemplary arrangement of the grid and the detector cell according to some embodiments of the present disclosure. To be convenient for description, only one detector cell and one grid used for adjusting the active area of the detector cell are shown in FIG. 10-A. It should be noted that a detector including a plurality of detector cells may be used for acquiring X-ray signals (see FIG. 8). And it should be noted that at least one grid may be used for adjusting the active area of the detector cells (e.g., two grids may be used, see FIG. 8). As illustrated in FIG. 8, a grid may include one or more radiation transmitting portions 603-B (or 604-B) and one or more radiation absorbing portions 603-A (or 604-A). X-rays may be transmitted through the radiation transmitting portions while absorbed by the radiation absorbing portions. The radiation transmitting portion may be an empty gap, or may be filled with certain medium. Exemplary medium may include inorganic material, organic material, or the like, or any combination thereof. Exemplary inorganic material may include silicon, carbon fiber, glass, or the like, or a combination thereof. Exemplary organic material may include plastic, rubber, or the like, or a combination thereof. A radiation transmitting portion, or referred to as a radiation transmitting section, may be used for adjusting the active area of a detector cell. The active area of a detector cell may receive radiation from a radiation source that passes through at least one of a plurality of radiation transmitting sections of a grid. At least one of the radiation transmitting section may include at least one transmitting part located above a detector cell. The active area may correspond to the radiation transmitting section or portion in a grid located above the detector cell. The dimension of the active area of a detector cell may be comparable to the dimension of the detector cell. For example, assume the dimension of the detector cell is 1×1 mm2, the dimension of the active area corresponding to the transmitting part located above the detector cell may be less than 1 mm2, such as, from 9/10 mm2 to 1 mm2, or from ⅘ mm2 to 9/10 mm2, or from ¾ mm2 to ⅘ mm2, or from ½ mm2 to ¾ mm2, or from ⅖ mm2 to ½ mm2, or from ⅓ mm2 to ⅓ mm2, or from ¼ mm2 to ⅓ mm2, or from ⅕ mm2 to ¼ mm2, or from ⅙ mm2 to ⅕ mm2, or below ⅙ mm2, or the like. In some embodiments, the dimension of the detector cell may be P mm2 other than 1×1 mm2, and the dimension of the active area corresponding to the transmitting part located above the detector cell may be bP. The value of the factor b may be any number in the range (x, 1), such as ½, ⅓, ¼, ⅕, ⅙, 1/10, 1/20, 1/50, 1/100, or the like. As used herein, the variable x may be set by the system according to a default setting, or may be set by an operator, or may be set according to requirements of signal acquisition process. The value of x may be between 0 and 1. In some embodiments, the variable x may be set to be equal to or greater than 0.01, or 0.05, or 0.1, or 0.2, or 0.3, or 0.4, or 0.5, or 0.6, or 0.7, or 0.8. Merely by way of example, the radiation transmitting portions may be arranged along X-direction or along Z-direction to form a stripe pattern (e.g., the shape of the radiation transmitting portion is rectangle). In some embodiments, the shape of the radiation transmitting portion may be square, triangle, circle, oval, polygon, irregular shape, or the like, or a combination thereof. The area ratio of the radiation transmitting portions and the radiation absorbing portions may be a fixed value, or may be adjustable under different conditions. Similarly, the grid pitches among the radiation transmitting portions may be a fixed value, or may be adjustable under different conditions. Merely by way of example, a doctor or an operator other than the doctor (e.g., a health-care worker) may manually adjust the grid pitches according to requirements of signal acquisition process or according to requirements of image quality (e.g., resolution, S/N (signal/noise), amplification factor, or the like, or a combination thereof.). For another example, the operator may adjust the grid pitches based on instructions inputted by the doctor or a related operator, or based on system default, or based on options regarding preset parameters (e.g., different conditions correspond to different parameters). The preset parameters may include signal acquisition speed, size of detector pixel, emitting voltage, emitting current, temperature, or the like, or a combination thereof. FIG. 10-A provides one example regarding the adjusting of active area of a detector cell according to some embodiments of the present disclosure. A top view and a side view from Z-direction are shown. As illustrated, the region filled with slash lines represents the radiation absorbing portions of the grid, the region filled with points represents a transmitting part of a radiation transmitting portion of the grid, and the region with no fill represents the detector cell. In this example, the shape of the transmitting part of the radiation transmitting portions may be rectangle as illustrated in FIG. 10-A. During an X-ray image acquisition process, based the system default or instructions inputted by an operator, the grid may be controlled to move toward the detector cell or the focal spot. The controlling may be performed by the control module 220, or may be performed by the grid controller 430, or may be performed by any module or unit integrated in the system that may be configured for controlling positions or arrangements of components of the system. For purposes to be illustrative, a radiation transmitting portion or a transmitting part of a radiation transmitting portion may be arranged on the middle part of the detector cell, but it should be noted that this illustration will not limit the scope of the present disclosure. It may be seen from the top view and the side view that due to the existence of the radiation transmitting portion and the radiation absorbing portion of the grid, the active area of the detector cell is reduced. The active area of the detector cell may be adjusted by adjusting the radiation transmitting portion's shape, size, position, arrangement, or the like, or a combination thereof. The description of the arrangements of the grid and the detector cell are intended to be illustrative, and not to limit the scope of the present disclosure. Many alternatives, modifications, and variations will be apparent to those skilled in the art. The features, structures, methods, and other characteristics of the exemplary embodiments described herein may be combined in various ways to obtain additional and/or alternative exemplary embodiments. For example, other than the situation illustrated in FIG. 10-A, the size or shape of the radiation transmitting portion may be changed, thus the active area of the detector cell or the size of the transmitting part of the radiation transmitting portion may be accordingly reduced. In some embodiments, assume that the size of a detector cell illustrated in FIG. 10-A is S mm2, the size of the radiation transmitting portion or the size of the transmitting part of the radiation transmitting portion may be reduced to aS mm2 according to the requirements of signal acquisition process. The value of the factor a may be any number in the range of (0, 1) (e.g., ½, ⅓, ¼, ⅕, ⅙, 1/10, 1/20, 1/50, 1/100, etc.). Similarly the size of the radiation transmitting portion or the transmitting part of the radiation transmitting portion may be enlarged accordingly. FIG. 10-B provides another example regarding the adjusting of the active area of the detector cell according to some embodiments of the present disclosure. It may be seen from the top view that two transmitting parts 1002 of the radiation transmitting portion of the grid are arranged above the detector cell. Similarly the active area of the detector cell is reduced due to the existence of the radiation transmitting portion and the radiation absorbing portion. Referring back to FIG. 10-A, the active area of the detector cell may be adjusted or may be controlled by adjusting one or more parameters of the radiation transmitting portions. The parameters may include the shape, the size, the grid pitch among the radiation transmitting portions, the amount of the radiation transmitting portions, the position of the grid, the filling material of the radiation transmitting portions, or the like, or a combination thereof. As shown in FIG. 10-B, two transmitting parts of the radiation transmitting portions are arranged, it should be noted that the arrangement is only for purpose of illustration, and not intended to limit the scope of the present disclosure. Many alternatives, modifications, and variations will be apparent to those skilled in the art. The features, structures, methods, and other characteristics of the exemplary embodiments described herein may be combined in various ways to obtain additional and/or alternative exemplary embodiments. For example, other than the two exemplary arrangements, one, three or more transmitting parts of the radiation transmitting portions may be arranged above the detector cell. Thus the active area of the detector cell may be adjusted accurately and continuously. FIG. 11-A and FIG. 11-B are schematic diagrams showing another exemplary arrangement of the grid and the detector cell according to some embodiments of the present disclosure. Two grids are arranged above the detector array used for adjusting the active areas of the detector cells. To be convenient for illustration, only one detector cell is shown. According to this embodiment, two grids may be configured for adjusting the active areas of the detector cells illustrated in FIG. 8. In some embodiments, the two girds may be configured orthogonally, or may be arranged at a certain angle with each other. The angle may be 10°, 15°, 30°, 45°, 60°, or the like. The active area of the detector cell may be adjusted based on the change of the angle. The change of the angle may be performed based on system default, or may be based on instructions inputted by a doctor or an operator other than the doctor, or may be based on instructions or preset conditions loaded from the server. The change of the angle may be performed by the control module 220, or may be performed by the grid controller 430, or may be performed by any module or unit integrated in the system that may be used for controlling positions or arrangements of components of the system. The type of the two grids may be the same or may be different. FIG. 11-A provides one example regarding the adjustment of the active area of a detector cell according to some embodiments of the present disclosure. A top view, a side view from X-direction, and a side view from the Z-direction are shown. In this example, it may be seen from the top view that a “+” radiation transmitting region is generated by two orthometric grids. In some embodiments, the two grids may be arranged at a certain angle, and thus the radiation overlapping area may be adjusted by tilting one or both grids. The size of the “+” radiation transmitting region may be changed by changing the size or the shape of the radiation transmitting portions of the two grids. Thus the active pixels in the X-direction, the Z-direction, and the XY-plane may be adjusted and controlled. It should be noted that the active area may be determined by both the radiation transmitting regions of the grid(s) and the position of the focal spot. FIG. 11-B provides another example regarding the adjusting of active area of a detector cell according to some embodiments of the present disclosure. Similarly, a top view, a side view from the X-direction, and a side view from the X-direction are shown. In this example, a radiation transmitting region illustrated in FIG. 11-B is generated by two orthometric grids. Name the upper gird as the first grid and name the under grid as the second gird (see FIG. 8). In the example, the grid pitches among the radiation transmitting portions of the two grids may be different. It may be seen from the side view from the X-direction that one radiation transmitting portion of the first grid is arranged above the detector cell, and no radiation transmitting portion of the second grid is arranged on the detector cell. It may be seen from the side view from the Z-direction that two radiation transmitting portions of the second grid are arranged above the detector cell, and no radiation transmitting portion of the first grid is arranged on the detector cell. This description is only for purpose of illustration, more than one radiation transmitting portions of the first grid and other than two radiation transmitting portions of the second grid may be arranged above the detector cell. The radiation transmitting region of the detector cell may be adjusted and controlled by the two grids under different conditions. FIG. 12 is a schematic diagram showing another exemplary arrangement of the grid and the detector cell according to some embodiments of the present disclosure. As illustrated, the radiation transmitting portion of the grid is arranged on the edge of the detector cell. Similar to the situation that the radiation transmitting portion of the grid arranged in the middle of the detector cell, the active area of the detector cell may be reduced by the existence of the grid. For example, ½ of the transmitting part of the radiation transmitting portion of the grid is located above the detector cell, the active area of the detector cell is reduced as ½ of the area of the transmitting part of the radiation transmitting portion. In a further example, the grid may be caused to move along the X-direction or along the Z-direction, while approaching the edge of detector cell, the radiation transmitting region above the detector cell may vary in real time. According to desired image quality or signal acquisition requirements of different organs of the object, the gird may be controlled to move under a certain speed or along a certain route. In still a further example, there may be two or more grids. The grids may be controlled together or may be controlled independently. The moving of the grids may include translation, tilt, or the like, or a combination thereof. The adjusting of the active area of a detector cell may be in real time, or may be pre-set before the X-ray image acquisition process commences, or may be performed when needed. The description of the arrangements of the grid and the detector cell are intended to be illustrative, and not to limit the scope of the present disclosure. Many alternatives, modifications, and variations will be apparent to those skilled in the art. The features, structures, methods, and other characteristics of the exemplary embodiments described herein may be combined in various ways to obtain additional and/or alternative exemplary embodiments. For example, parameters regarding the adjusting of the active area of a detector cell may be controlled in real time and may be controlled independently. The parameters may include but not limited to, the size or shape of the radiation transmitting portion, the moving speed of the grids, the number of the grids, the angle between the grids, or the like, or a combination thereof. FIG. 13-A and FIG. 13-B are schematic diagrams showing exemplary arrangements of a grid, a shielding device, and a detector cell according to some embodiments of the present disclosure. For simplicity, only a portion of a grid, a part of a shielding device, and a detector cell are shown in FIG. 13-A and FIG. 13-B. It is for illustration purposes and not intended to limit the scope of the present disclosure. It is understood that an imaging system may include more than one grids, that a grid may include more than one shielding device, and that an imaging system may include more than one detector cells. In FIG. 13-A, a top view from the Y-direction is shown. A plate of the shielding device 1302 may be placed on or above the grid 1301. In some embodiments, the shielding device 1302 and the grid 1301 may physically contact or be in direct contact with each other. In some embodiments, the shielding device 1302 and the grid 1301 may be spaced apart from each other by a distance. In some embodiments, the plate of the shielding device 1302 may contact the radiation absorbing portion 1301-A of the grid 1301. In some embodiments, the plate of the shielding device 1302 may contact the radiation transmitting portion 1301-B of the grid 1301. In some embodiments, the shielding device 1302, or a portion thereof, may be parallel to the grid 1301. In some embodiments, the shielding device 1302, or a portion thereof, may be placed at an angle of inclination with respect to the grid 1301. The angle may be adjustable from 0° to 360°. In FIG. 13-B, the radiation absorbing portion 1301-A may be filled with materials including gas, therefore, the shielding device 1302 may be place on a side of the radiation absorbing portion 1301-A of the grid 1301 as shown in FIG. 13-B. It should be noted that the position of the shielding device shown in the figure is merely an exemplary example, and not intend to be limiting. In some embodiments, the shielding device 1302 may be any position in the radiation absorbing portion 1301-A. In some embodiments, the shielding device 1302 may be placed apart from the grid with a distance. For the purposes of describing conveniently, FIG. 13-B may show an exemplary example. In FIG. 13-B, a side view from Z-direction of the arrangement is shown. A plate of the shielding device 1302 is illustrated in HG, 13-B. The plate of the shielding device 1302 may be movably attached to a side of the radiation absorbing portion 1301-A at a connecting point 1304. The plate of the shielding device 1302 may swing around the connecting point 1304 by any angle between, for example, 0° to 90°, or 0° to 180°, or 0° to 270°. The trajectory of one end of the plate in the shielding device 1302 may form an arc with a radius. When the plate of the shielding device 1302 is at different positions, the active area of the detector cell 1303 may be different. The different length or width of the plate of the shielding device 1302 (the radius shown in FIG. 13-B) may also result in different active area of the detector cell 1303. The shape of the shielding device 1302 may be regular or irregular. Merely by way of example, the shielding device 1302 may be one or more plates with dimensions including, for example, a length, a width, a height, etc. The length and the width of a plate of the shielding device 1302 may be comparable to a radiation transmission section portion 1301-B of the grid 1301. The working condition or a position of the shielding device 1302, or a portion there of (for example, a plate of the shielding device 1302) may include an extended position, a partially extended position, and a contracted position. As used herein, an extended position of the shielding device 1302, or a portion there of, may be one at which the shielding device 1302, or a portion thereof, completely blocks or absorbs one or more radiation transmission section portions 1301-B of the grid 1301, and no area(s) of one or more radiation transmission section portions 1301-B of the grid 1301 may be available for passage of radiation. As used herein, a partially extended position of the shielding device 1302, or a portion there of, may be one at which the shielding device 1302, or a portion thereof, partially blocks one or more radiation transmission section portions 1301-B of the grid 1301, and partial area(s) of one or more radiation transmission section portions 1301-B of the grid 1301 may be available for passage of radiation. As used herein, a contracted position of the shielding device 1302, or a portion there of, may be one at which the shielding device 1302, or a portion thereof, does not block any part of one or more radiation transmission section portions 1301-B of the grid 1301, and the entire area(s) of one or more radiation transmission section portions 1301-B of the grid 1301 may be available for passage of radiation. The blocking of radiation by the shielding device 1302 or a portion thereof may be achieved by reflection or absorption. The working conditions of the shielding device 1302 may include the position relative to the detector cell or the grid 1301, the angle relative to the detector cell or the grid 1301, the motion speed of the shielding device 1302 or a portion thereof, the motion direction of the shielding device 1302 or a portion thereof, or the like, or any combination thereof. In some embodiments, the movement of the shielding device 1302 may include a motion along a certain direction, e.g., the X-direction, the Y-direction, or the Z-direction. In some embodiments, the shielding device 1302 may tilt with respect to a certain axis or with respect to the grid 1301. When the whole or part of the shielding device 1302 is above the radiation transmitting portion 1301-B of the grid 1301, the shielding device or a portion thereof is in its extended position or partially extended position, and the radiation blocked or absorbed by the shielding device 1302 may cause a change of the respective active area of the detector cell. The control module 220 in the system may control the working condition or position of the shielding device 1302, or a portion thereof (for example, one or more plates of the shielding device 1302 as illustrated in FIG. 13-A and FIG. 13-B), to adjust the active area of a detector cell, or the part of the radiation transmission portion 1301-B of the grid 1301 that may be available for passage of radiation. The control may be achieved by controlling a voltage, a current, an electric field, a magnetic field, or the like, or any combination thereof, that may be used to adjust the working condition or position of the shielding device 1302, or a portion thereof. It should be noted that the above description about the shielding device is merely an example, and not intended to limit the scope of the present disclosure. For persons having ordinary skills in the art, various variations and modifications may be conducted under the teaching of the present disclosure. However, those variations and modifications may not depart from the protecting of the present disclosure. Exemplary variations may include that each grid may be equipped with one or more shielding devices, that multiple shield devices of a grid may be the same or different shielding devices, and that the dimensions of the shielding device of one grid may be the same as or different from that of another grid. The change of the working condition of the shielding device of one grid by way of the motion of the shielding devices or a portion thereof may be synchronized with or different from that of the second grid. The synchronization of the motion of two shielding devices or a portion thereof may include one or more characteristics including, for example, uniform rate or speed of the motion, uniform direction of the motion, uniform timing of the motion, or the like, or a combination thereof. For another example, the dimensions of the part of the shielding device in each transmitting portion of one grid may be the same or different. The change of the state of the shielding device in each transmitting portion of one grid may be the same or different. For instance, the shielding device relating to one grid may tilt with respect to an axis by a first angle, and the shielding device relating to another grid may tilt with respect to another axis by a second angle. As used herein, the first angle may be the same as or different from the second angle. Having thus described the basic concepts, it may be rather apparent to those skilled in the art after reading this detailed disclosure that the foregoing detailed disclosure is intended to be presented by way of example only and is not limiting. Various alterations, improvements, and modifications may occur and are intended to those skilled in the art, though not expressly stated herein. These alterations, improvements, and modifications are intended to be suggested by this disclosure, and are within the spirits and scope of the exemplary embodiments of this disclosure. Moreover, certain terminology has been used to describe embodiments of the present disclosure. For example, the terms “one embodiment,” “an embodiment,” and/or “some embodiments” mean that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present disclosure. Therefore, it is emphasized and should be appreciated that two or more references to “an embodiment” or “one embodiment” or “an alternative embodiment” in various portions of this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures or characteristics may be combined as suitable in one or more embodiments of the present disclosure. Further, it will be appreciated by one skilled in the art, aspects of the present disclosure may be illustrated and described herein in any of a number of patentable classes or context including any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof. Accordingly, aspects of the present disclosure may be implemented entirely hardware, entirely software (including firmware, resident software, micro-code, etc.) or combining software and hardware implementation that may all generally be referred to herein as a “block,” “module,” “engine,” “unit,” “component,” or “system.” Furthermore, aspects of the present disclosure may take the form of a computer program product embodied in one or more computer readable media having computer readable program code embodied thereon. Similarly, it should be appreciated that in the foregoing description of embodiments of the present disclosure, various features are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure aiding in the understanding of one or more of the various inventive embodiments. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed subject matter requires more features than are expressly recited in each claim. Rather, inventive embodiments lie in less than all features of a single foregoing disclosed embodiment.
043354653	summary	BACKGROUND OF THE INVENTION The present invention concerns firstly a method for producing and accelerating electrons and ions under application of a voltage, whereby electrodes are proposed which, under the influence of a voltage, supply electrons, and a gas being proposed which, under low pressure, supplies electrons and ions. It is known in the art to produce electron flows in a vacuum by means of thermionic emission or by point discharges, and to consequently accelerate in a corresponding voltage field. The current densities which are thereby obtainable are insufficient. In the prior art, electrons which were produced in a vacuum have been deposited through a thin foil into a chamber in which is located a gas which is under low pressure. Eventhough it is possible to thus obtain in this low-pressure area electron flows having a high current density, however, the amount of instruments required is very high and the effect is unsatisfactory. SUMMARY OF THE INVENTION It is the scope of the present invention to provide not only a method but also a particle-accelerator and arrangements formed therewith, which, at a substantially higher effectiveness, produce an electron flow and in given cases also an electron flow of a very high current density with comparatively simple instruments. The present invention utilizes a method of the above-mentioned species of the invention, with electrodes which are located at a distance apart from one another and are screened outwardly. At least one gas discharge channel is provided, which is formed of aligned openings of at least the inner electrodes. Within the electrodes provision is made for an ionisable low pressure gas to be placed, and for the electrodes to be connected to a voltage of a strength so that it substantially collapses in a spark-like gas-discharge. One obtains thereby a controlled spark penetration, which may also be characterized as a "pseudo-spark". The current density which is obtainable in the low pressure gas is substantially higher than the density of an electron- or ion-flow in the vacuum. The low-pressure spark-discharge which is obtainable by means of the present invention is stable and reproducable. While in many methods for producing an electron- or ion-flow the effectiveness lies in the area of 0.1 to 1%, an effectiveness of 30% and higher can be obtained with the present invention. In comparison with the common spark penetrations, however, the developing sporadic process of the spark-channel and the developing contraction in the actual discharge-path in the gas chamber is prevented, in so far as the inside pressure between the electrodes is maintained correspondingly low. The difference from a vacuum which differs in its pressure from a low pressure by multiple ten percent should be noted. While, for example, with the present invention at an electrode-distance of one millimeter there resulted a preferred low pressure value of 0.5 mbar, the pressures of a vacuum are in the area of 10.sup.-3 to 10.sup.-4. In contrast to the vacuum-discharge, the low-pressure gas content in the instant invention has an active function. The above-noted effects, or advantages, are produced in that the low pressure gas-discharge is made not at the outside edge of the electrodes but in the gas-discharge channel. The discharge is localized there. In this low pressure electrode system under application of a voltage there develops the tendency of transition in a type spark-discharge and simultaneously the localization of this discharge in the area of the discharge channel. In a preferred embodiment of the present invention which is not limited to the aforesaid, it is proposed that the product p.times.d be located in the size arrangement of 0.05 to 0.5 mbar.times.mm. Thereby, p represents the inside pressure between the electrodes in mbar, and d represents the distance in mm between the individual electrodes. Additional embodiments of the present invention are explained in more detail in the special description of the drawings. The present invention further concerns a particle accelerator for performing the above-mentioned method and proposes in this regard at least two electrodes at equidistance; that at least the inner electrodes have each an opening, whereby associated openings of electrodes are along one line and forming the gas discharge channel; that the outer surfaces or outer edges of the electrodes are enclosed by an insulating housing, and that means for gas-supply and, if required, for producing the low pressure necessary inside the electrodes, are provided. Such a particle accelerator may be manufactured with a relatively low constructive expenditure and therefore at comparatively low costs. It distinguishes itself, however by the afore-mentioned high efficiency. In toto, a very efficient production of electron- or ion-flows is obtained. According to the embodiments of the present invention, outflow-openings may be provided at one end or at both ends of the gas-discharge channel for the accelerated electrical particles. In special cases of application, it would also be possible not to provide for any outflow-openings.
	abstract	An apparatus for safely controlling a control rod of a nuclear reactor of a nuclear power plant. The apparatus includes a first controller to output a signal to insert or withdraw the control rod. A mechanical portion performs insertion or withdrawal of the control rod in response to the outputted signal. The mechanical portion includes a latch engagement portion, a stop latch to restrain the control rod, a moving latch to move the control rod, and a lift coil to insert or withdraw the control rod. A detector can detect a position or a speed of the control rod. A brake is configured to stop the control rod by force. A second controller operates the brake in response to a brake signal from the detector. The second controller controls the brake independent of the first controller.
042645409	description	DESCRIPTION OF PREFERRED EXAMPLES In typical experiments 0.5% by weight of ball-milled niobium pentoxide was blended with uranium dioxide powder and granulated with 0.2% by weight of zinc stearate as a lubricant before pressing into compacts of diameter 1.1 cm and sintering in moist hydrogen for 4 hours at 1700.degree. C. The following results were obtained by addition of water vapour to provide the oxygen potential. 1. At low moisture contents of less than 1000 parts per million by volume (vpm) density increased with increasing moisture content from 95% theoretical density (TD) to 98.5% while grain size increased from 14-35 microns. 2. At moisture contents between 1000 and 20,000 vpm density remained fairly constant at approximately 98.5% TD while grain size increased to at least 60 microns. For example, with a moisture content of 15,000 vpm a grain size of 50 microns was obtained. 3. Moisture contents over about 20,000 vpm gave a progressive reduction in density (and a decrease in the reproducibility of the density results). A typical result at 25,000 vpm moisture was about 95% TD with a grain size of 80 microns. A similar effect on grain size can be obtained by adding carbon dioxide instead of water to the hydrogen sintering atmosphere as the following results show ______________________________________ Grain size vpm CO.sub.2 % TD (microns) ______________________________________ 1000 94.0 12 7500 98.5 42 15000 99.0 58 ______________________________________ It was also found that the upper limit of moisture content varied with various parameters. High densities and large grain sizes could be obtained at higher moisture contents by (a) Reducing the density of the green (unsintered) compact say from 5.75 g/cm.sup.3 to 5.2 g/cm.sup.3 PA0 (b) Reducing the heating rate during sintering say from 300.degree. C. per hour to 50.degree. C. per hour. From all the above results it follows that, if the presently desired grain size of about 40 microns is to be achieved by adding 0.5% by weight of niobium pentoxide to the nuclear fuel and using the practicable and economic sintering time and temperature of 4 hours at 1700.degree. C., the moisture level in a hydrogen sintering atmosphere should be maintained between 1000 and 9000 vpm. For a most satisfactory microstructure, however, it is considered that the optimum value within this range is 5000-7000 vpm for a water in hydrogen atmosphere and that for a carbon dioxide in hydrogen atmosphere the optimum carbon dioxide content is 7000-8000 vpm. Varying the quantity of niobium pentoxide added affects the results too. Fuel pellets have been made with additions of niobium pentoxide as low as 0.25% by weight. A grain size of 25 microns was easily produced on sintering for 4 hours at 1700.degree. C. in a hydrogen atmosphere containing 6000 vpm water vapour. With an increase in the addition of niobium pentoxide to 0.35% by weight grain sizes in excess of 30 microns were produced under the same conditions. The optimum results were obtained at 1700.degree. C. with additions of 0.5% by weight of niobium pentoxide. With an increase in sintering time or sintering temperature it is to be expected however that less niobium pentoxide will be required to produce a given grain size. Controlled porosity may be introduced into the sintered pellets by the inclusion of a fugitive pore former in the compact, as described, for example in U.K. Pat. No. 1,461,263.

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