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	claims	1. A semiconductor circuit test method comprising:a first step configured to generate a basic format of a test pattern and storing the basic format in a test device, the basic format including at least one parameter and a test program for testing a test target semiconductor circuit;a second step configured to set a predetermined value for the parameter to generate the test pattern including the test program and the parameter set to the predetermined value and supplying the test pattern to the test target semiconductor circuit;a third step configured to store the test program in a first address of a storing module in the test target semiconductor circuit and storing the parameter set to the predetermined value in a second address of the storing module; anda fourth step configured to execute the test program stored in the first address while referring to the parameter stored in the second address. 2. The method of claim 1, wherein after the fourth step, the second to fourth steps are performed a plurality of times while changing a value to be set for the parameter. 3. The method of claim 1, wherein upon the second step, a plurality of values are set for the parameter to be supplied to the test target semiconductor circuit,upon the third step, the plurality of values are stored in corresponding addresses of the storing module respectively, andupon the fourth step, the test program is executed while referring to the parameter set to one of the plurality of values. 4. The method of claim 1, wherein the test program includes at least a pointer for referring to the parameter, andupon the fourth step, the parameter is referred to based on the pointer. 5. The method of claim 4, wherein the number of the pointer included in the test program is equal to the number of the parameter or equal to a product of the number of the parameter and the number of test to be conducted. 6. The method of claim 4, wherein the pointer corresponds to the second address of the storing module. 7. The method of claim 1, wherein the test pattern is serial data, andthe test pattern is supplied to the test target semiconductor circuit through one input pin of the test target semiconductor circuit. 8. The method of claim 1, wherein the test program is a program to test a memory comprising a plurality of pages in the test target semiconductor circuit, andthe parameter comprises:an initial write address of the memory;the number of write pages; andwrite data. 9. The method of claim 1, wherein the basic format includes a program execution time indicative of a time required for a test, the program execution time being calculated dependent on the test in advance. 10. The method of claim 1, wherein the basic format includes an output expectation value indicative of an expectation value of an output obtained as a result of a test on the test target semiconductor circuit. 11. A semiconductor circuit comprising:an input pin a test pattern is inputted to, the test pattern including at least one parameter set to a predetermined value and a test program;a storing module configured to store the test pattern;a controller configured to store the test pattern in a first address of the storing module and to store the parameter set to the predetermined value in a second address of the storing module; anda test executing module configured to execute the test program stored in the first address while referring to the parameter stored in the second address. 12. The circuit of claim 11, wherein the test program includes a pointer for referring to the parameter, andthe test executing module is configured to refer the parameter based on the pointer. 13. The circuit of claim 12, wherein the number of the pointer included in the test program is equal to the number of the parameter or equal to a product of the number of the parameter and the number of tests to be conducted. 14. The circuit of claim 12, wherein the pointer corresponds to the second address of the storing module. 15. The circuit of claim 11, wherein the storing module is configured to store the parameter set to a value for one test or store the parameter set to values for all of tests to be conducted. 16. The circuit of claim 11, wherein the test pattern is serial data, andthe test pattern is supplied through one input pin. 17. The circuit of claim 11, wherein the test program is a program to test a memory comprising a plurality of pages, andthe parameter comprises:an initial write address of the memory;the number of write pages; andwrite data. 18. The circuit of claim 11, wherein the basic format includes a program execution time indicative of a time required for a test, the program execution time being calculated dependent on the test in advance. 19. The circuit of claim 11, wherein the basic format includes an output expectation value indicative of an expectation value of an output obtained as a result of a test on the semiconductor circuit. 20. A semiconductor circuit test system comprising:a test target semiconductor circuit; anda test device configured to generate a test pattern including at least a parameter set to a predetermined value and a test program,wherein the semiconductor circuit comprises:an input pin the test pattern is inputted to;a storing module configured to store the test pattern;a controller configured to stored the test pattern in a first address of the storing module and to store the parameter set to the predetermined value in a second address of the storing module; anda test executing module configured to execute the test program stored in the first address while referring to the parameter stored in the second address.
039322157	description	Referring now to the drawing and first, particularly, to FIG. 1 thereof, there is shown therein an absorber 1 formed of three members that is guided in a guide tube 2 which, at its lower end, is held in a sleeve 3 that is secured to the grid support plate 4. During operation of the reactor, the lower end of the absorber 1 rests in a correspondingly shaped end section 5 of the guide tube 2, sealing it, and thereby largely prevents coolant from entering the guide tube 2. The guide tube 2 is held at its upper end in a centering tube 6. The absorber 1 is connected through a connecting device 7, which need not be described in detail as it is not essential to the invention, to one end of a tie rod 8. The other end of the tie rod 8 is secured to the lower part of a bayonet coupling 9 of conventional construction. The latter, in turn, is connected with the upper part thereof to a connecting rod 10. When the connecting rod 10 is turned, it causes disengagement of the bayonet coupling 9, whereupon the entire device can be pulled up and only the parts 1 to 5, 7 and 8 of the control rod remain in the reactor in the shut-off position of the control rod. In FIG. 2, the reduced-diameter centering tube 6 and guide bearing 11 form a dashpot 12 in which the connecting rod 10 displaces a damper piston 13 that is mounted thereon, thereby braking the motion of the absorber mechanism, when it is moved rapidly upwardly to the shut-off position shown, prior to reaching that final shut-off position. The centering tube 6 is mounted in a tube 14. Shielding 16 is disposed in the space between the inner surface of the tube 14 and the outer surface of a tube 15 disposed within and coaxially to the tube 14. The tube 15, in turn, surrounds a guide tube 17. In FIG. 3, the tube 14 is seated with a shoulder thereof on the lid of the reactor. A cover 18 seated on the tube 15 closes off the shield 16 at the top thereof. A sleeve 20 connected to the tube 17 and provided with an external thread and a conical seal 19, is disposed on the cover 18. Upon rotating a tube 23 in which a nut 21 is disposed, the sleeve 20 is screwed into the nut 21 until a conical seal 19 comes to rest against a correspondingly shaped interior cone 22, so that gas is prevented from escaping from the reactor by a seal 53. At the same time, the centering tube 6 is lifted through the tube 17 for such a distance that a gap is formed at the junction between the centering tube 6 and the guide tube 2 (note FIG. 1), and it is thereby possible to rotate the reactor lid to carry out fuel element replacement operations. The tube 23 is connected through a gear coupling 24 with a sleeve 25 which, at the upper end thereof, is provided with a gear 26 that meshes with a pinion 27 mounted on a universal joint drive shaft 28. The gear coupling 24 is required so that, when a chuck 29 of conventional construction, is disengaged, the tube 23 can be separated from the housing 30 that is slid over it. The universal-joint shaft 28 with its pinion 27 are supported in the housing 30, as well as a universal-joint shaft 31 with a pinion 32 secured thereto, which engages a gear 33 mounted on a shaft 34 that is connected to the rod 10 through the chuck 29. When the chuck 29 is disengaged, the parts of the device which have been in contact with the coolant can be separated from the other parts. The chuck 29 also facilitates the installation or assembly of the device. The housing 30 is connected to a tube 36 through an intermediate section 35. FIG. 4 shows the tube 36, in which a holding plate 37 is secured. A helical spring 38 bears against the holding plate 37. If a lead screw 39 is turned, the rotation thereof is transformed into axial motion by a nut 40, and a disc 41, which is rigidly connected to the nut 40 and is prevented from turning by a retaining slot 42 on the inside of a tube 43, slides downwardly. On the disc 41, there is secured a toroidal electromagnet 44, the leads of which are not illustrated. In the energized condition, the electromagnet 44 entrains an armature 45 resting against it, which slides along retaining slots 46 formed on the inside of the tube 36. The helical spring 38 is thereby stressed and the tube 43, which is firmly connected to the armature 45, slides farther downwardly and thereby lowers the shaft 34 suspended in a holder 47, the shaft 34 being drawn downwardly by the gravity force of the absorber 1, which is connected to it by the parts 29, 10, 9, 8 and 7. A stop 48 limits the travel of the armature 45 upwardly during shut-off. A gas seal 49 prevents radioactively contaminated gases from escaping from the reactor. The lead screw 39 is turned by an electric motor 52 which operates through a reduction gear 50 and an overload clutch 51, of conventional construction and therefore not further described in detail. The overload clutch 51 prevents the drive mechanism from being damaged in the event of jamming of the linkage. The universal-joint shafts 28 and 31 are constructed at the upper end thereof so that they can be rotated, for example, by means of a wrench. The upper part of the entire device is secured in a holder plate 54. The traction device forms one unit during normal operation, but in the event of the reactor cover having to be rotated or lifted off for maintenance work, is divisible into a lower part (connecting device 7, tie rod 8 lower half of bayonet coupling 9) and an upper part (upper half of bayonet coupling 9, connecting rod 10, chuck 29, shaft 34, holder 47, tube 43 and armature 45). The parts linking the absorber to the spring 38 which are set in motion when rapid shut-off is triggered include connection device 7, tie rod 8, bayonet coupling 9, connecting rod 10, chuck 29, shaft 34 holder 47, tube 43 and armature 45. Referring to FIG. 5, the bayonet coupling 9 comprises an upper part 55 and a lower part 56 detachably connected to each other by means of a gear coupling which is also shown in FIG. 6. The rod 10 is provided with segments 58 which can engage appropriately shaped recesses 59 of the lower coupling part 56. FIG. 6 shows the coupling in disengaged condition whereby the rod 10 and thus segments 58 and the upper part 55 of the coupling can be pulled away in an upward direction. When the rod 10 is rotated 90 degrees, segments 58 engage the recesses 59 and lock the coupling parts 55 and 56 with respect to each other, and their mutual gearing prevents the rotary movement of the rod 10 from being transmitted to the lower coupling part 56 and to the remaining parts 1, 7, 8 of the device suspended thereon. A Part 60 is provided at its upper end with an internal hexagon opening for accomodating a hexagon part 57 so that the rotary movement of the rod 10 can be transmitted to the part 60. The part 60 is provided with two flanges 61, 62 which, in the illustrated embodiment, each comprise three control slots 63 as shown in FIG. 7. Inside the control slots, are disposed glide pins 64, which have latches 65 attached thereto and which, at an appropriate position of the pins 64 in the control slots 63, as shown in FIG. 7 for example, engage the openings 66 in the guide tube 2. The operation of this latch system and the bayonet coupling 9 is coupled that upon rotation of the rod 10 for releasing the coupling parts 55 and 56 from each other, segments 58 emerge from recesses 59 thereby releasing the coupling and this same rotation shifts, simultaneously, part 60 and thereby the guide slots 63 in such a manner that the latches 65 engage the opening 66. As a result, coupling parts 55 and 56 which are geared with each other, as well as the hexagon part 57 and part 60 are released from one another, through a simple pulling upwardly of the rod 10 while the absorber 1 remains securely locked in its disconnected position. The high temperatures prevailing in the fission zone of the reactor, the radiation stress, and possible interferences make the pull rod 8 particularly susceptible to danger of being damaged. To insure that, in any event, the absorber 1 will be pulled into the core region, the upper and lower end parts of the pull rod 8 (FIG. 5 shows only the upper end part 67) are so arranged that a wire rope 69, whose ends are provided with ballshaped holders 68, can be guided in the interior of the hollow pull rod 8 as a reserve pulling member. FIG. 8 shows how the individual parts of the absorber 1 are connected by means of joints which consist of meshing extension sections or bulges 70 and 71 which are disposed at various locations. The individual parts of the absorber 1 are limited by stops, 72, 73 and can be shifted relative to each other, to a certain degree and especially, may be tilted, canted, and twisted oppositely relative to each other so that absorber 1 can also follow through guide tube 2 which becomes curved due to a disruption or the like. The operation of the device is as follows: When rapid shut-off is triggered, the electromagnet 44 ceases to carry current and releases the armature 45 which is forced upwardly by the stressed helical spring 38 to the stop 48 and thereby entrains the tube 43. The shaft 34 suspended in the mounting 47 is also forcibly pulled upwardly and, in turn, pulls up the chuck 29, the rod 10, the bayonet coupling 9, the tie rod 8 and the fastening device 7 and thereby draws the absorber 1 into the reactor core region. Simultaneously, the electric motor 52 is started up and pulls up the disc 41 through the reduction gear 50, the overload clutch 51 and the lead screw 39 and thereby forcibly entrains the armature 45, in case the latter should not have been impelled to its upper rest position. After correcting the reactor trouble which caused the aforedescribed rapid shut-off, the operational readiness of the device is restored as follows: The electric motor 52 is driven in the opposite rotary direction, and through the lead screw 39, causes a lowering or unscrewing of the nut 40, and the disc 41 and the electromagnet 44, which is simultaneously energized and thereby entrains the armature 45 downwardly against the biasing force of the helical spring 38. The tube 43 and the holder 47 connected thereto, are thereby moved downwardly, so that, due to the force of gravity, the absorber 1 which is suspended on it by means of the parts 34, 29, 10, 9, 8 and 7 slides downwardly out of the reactor core region, until the lowermost member of the absorber 1 rests in the end section 5 of the guide tube 2, thereby terminating the shut-off of the reactor. To disengage the bayonet coupling 9, the universal joint shaft 31 is rotated, imparting its rotation through the pinion 32 to the gear 33, and through the latter to the shaft 34 which, in turn, sets the connecting rod 10 in rotation through the chuck 29, and thereby initiates the coupling operation. The rotation of the universal-joint shaft 28, through the pinion 27 and the gear 26, causes rotation of the sleeve 25 which, through the gear coupling 24, turns the tube 23 and the nut 21 in which the sleeve 20 is screwed and which is fastened in the tube 23. The tube 17 connected to the sleeve 20 rises and entrains the centering tube 6, whereby the latter's connection to the guide tube 2 is released and a gap between these two tubes 6 and 17 is formed. After disengagement of the bayonet coupling 9, the reactor lid, with the parts of the device built into the same, is then rotatable, while the parts 1 to 5, 7 and 8 remain fixed in the reactor.
061817627	description	DETAILED DESCRIPTION OF THE INVENTION Referring now to FIG. 1, there is illustrated a fuel bundle B having fuel rods arranged according to the present invention. Bundle B includes an outer channel C surrounding a plurality of fuel rods 10 extending generally parallel one to the other between upper and lower tie plates U and L, respectively, and in a generally rectilinear matrix of fuel rods as illustrated in FIG. 2. The rods 10 are maintained laterally spaced from one another by a plurality of spacers S vertically spaced one from the other along the length of the fuel rods within the channel C. The fuel bundle B illustrated in FIG. 1 is conventional in all respects except that the fuel rods are arranged to have different peak power limits in the bundle as set forth below. Referring now to FIG. 2, there is illustrated an array of fuel rods, i.e., in this instance, a 10.times.10 array, surrounded by the fuel channel C. The fuel rods 10 are arranged in orthogonally related rows and also surround one or more water rods, two water rods 12 being illustrated. The fuel bundle B is arranged in one quadrant of a control rod 14 as is conventional, it being appreciated that a fuel bundle is arranged in each of the other quadrants of the control rod and that the bundles constitute part of a large number of bundles disposed in a nuclear reactor core. In accordance with a preferred embodiment of the present invention, the fuel bundle B has differential peak power limits for the fuel rods. Preferably, the peak power limit for the fuel rods comprising the periphery or edge of the bundle have a higher peak power limit than the peak power limit of the fuel rods interior of the peripheral rods. The peripheral or edge fuel rods are identified in FIG. 2 at 10p, while the interior rods are identified at 10i. By increasing the peak power limit of the peripheral or edge fuel rods which typically operate at higher power levels, higher bundle power producing capability is achieved. As well known to those of skill in this art, the maximum or peak power limit is the maximum power output per unit length of fuel rod for steady state operation. Each and every fuel rod in the fuel bundle must operate at or below the peak power limit. Because of the heterogeneous nature of the bundle lattice in a boiling water reactor, the fuel rods of the fuel bundle will have different margins between their actual power output and the peak power limit. It has been observed that the fuel rods near the regions of high water density and large thermal neutron density exhibit relatively higher power output than other fuel rods adjacent regions of less water density and smaller neutron densities. Typically, the fuel rods on the edge or periphery, i.e., rods 10p of the fuel bundle B, typically operate at output powers higher than the majority of the interior rods, although fuel rods adjacent the water rods 12 also exhibit higher power outputs than other interior fuel rods. In a conventional nuclear fuel bundle, all of the fuel rods have the same power limit, beyond which they may not operate. Given that all of the fuel rods of that bundle operate at different power outputs, any power increase in the entire bundle, while operating the nuclear reactor, will decrease the margins until one of the fuel rods operates at the peak power limit. Because the edge or peripheral fuel rods 10p normally operate at power outputs higher than the power outputs of the interior rods, one or more of the edge or peripheral rods will approach and obtain the peak power output before the remaining interior rods. Once that limit is reached, it will be appreciated that there remain significant power output operating margins in a number of the other, primarily the interior fuel rods, which to that extent are under-utilized. By increasing the peak power limit for the rods which would otherwise first approach or obtain the lower peak power limit common to all rods of a conventional fuel bundle, i.e., edge rods, in comparison with the peak power limit of those operating with greater margins, i.e., interior rods, it will be appreciated that the power output of the entire bundle can be increased during operation of the nuclear reactor. This is because the power output of the peripheral or edge fuel rods may be increased to decrease their margin and approach the higher peak power limit. To accomplish this, i.e., to enable operation of the edge or peripheral fuel rods at or below a higher peak power limit than the peak power limit of the interior rods with an overall increase in bundle power output, a decrease in the magnitude of the nuclear fuel is provided in each of the edge or peripheral rods in comparison with the magnitude of the nuclear fuel provided the interior rods. This can be accomplished in a number of different ways. For example, the length of the column of nuclear fuel in each of the edge or peripheral rods may be shortened with respect to the length of the column of nuclear fuel for each of the interior rods thereby increasing the fission gas volume of the fuel rod, principally plenums 15a and 15b relative to the fuel volume as evident from a comparison of FIGS. 3A and 3B. It will be appreciated that typically the nuclear fuel in the fuel rods is contained in pellets 13 (FIGS. 3A and 3B) stacked one on top of the other within the nuclear fuel rod 10. By reducing the length of the stack of pellets by omitting one or more pellets or forming pellets shorter in length, the length of the nuclear fuel column in the peripheral or edge fuel rods 10p, as illustrated in FIG. 3B, can be shortened thereby increasing the ratio of plenum/fuel within the fuel rod. As seen in FIG. 3B in comparison with the prior art of FIG. 3A, the plenums 15a and 15b are increased in volume at the top and bottom, respectively, of the fuel rod. That is, fuel is reduced in the low power regions adjacent the top and bottom of the edge rods as compared with the interior rods while the magnitude of fuel in the high power regions intermediate the length of the fuel rod remains the same. Another way of reducing the magnitude of the nuclear fuel in the edge or peripheral fuel rods in comparison with the interior rods is to reduce the diameter of the fuel pellets. Thus, in FIG. 4A, a conventional fuel pellet having a very small gap a between the interior wall of the fuel rod 10 and the exterior wall surface of the pellet 13 is illustrated. In accordance with the present invention, as illustrated in FIG. 4B, the diameter of the fuel pellets 13 within the edge or peripheral fuel rods 10p can be reduced whereby the gap b between the interior wall surface of the fuel rod 10p and the exterior wall of the fuel pellet 13 is increased, hence reducing the magnitude of nuclear fuel in the rods and hence increasing the gas plenum/fuel ratio. Additionally, the density of the nuclear fuel can be diminished or decreased in the edge or peripheral rods. It will therefore be appreciated that by reducing the magnitude of the nuclear fuel in the lattice positions which typically exhibit higher power outputs, i.e., the edge or peripheral lattice positions, the power output of those fuel rods occupying the edge or peripheral positions, is reduced. However, during operation of the nuclear reactor, the power output of the bundle can be increased beyond the power output otherwise available from a bundle having a conventional single peak power limit because power peaking occurs in the edge rods which, in accordance with the present invention, have increased peak power limits to afford greater margin. The capability for operating the nuclear reactor at higher power outputs is significantly more important than effecting a minor reduction in the magnitude of the nuclear fuel available in the edge or peripheral rods, particularly in the low power output regions of the rods, i.e., the top and bottom. It is, of course, important that the mass of nuclear fuel within the bundle be maintained at the highest level possible to produce the highest energy output. The minor reduction in the magnitude of nuclear fuel in the edge or peripheral rods is small in comparison with the overall fuel mass within the bundle and is preferably taken from one or more low power output regions. Power output is therefore not generally affected by reducing the fuel in the low power regions of the edge rods but beneficially the gas plenum volume is increased, enabling higher power outputs by increasing enrichment in the edge rods and operating interior rods with decreased margin vis-a-vis the lower peak power limit. With differential peak power limits, there is thus the significant benefit of adding increased power output capability during nuclear reactor operation. Consequently, a significant aspect of the present invention resides in the edge or peripheral rods having the higher peak power limit in those higher power locations in the bundle lattice and comparatively greater magnitudes of nuclear fuel in comparison with the interior rods which have a comparatively lower peak power limit in bundle lattice locations with naturally lower power outputs. It will therefore be appreciated that increased fissile loadings or fuel enrichments can be provided the outer or peripheral rods of the fuel bundle. Thus, additional fissile content can be placed in the edge or peripheral fuel rods and they can be operated at higher power levels, even though there is a lesser magnitude of nuclear fuel in the edge or peripheral rods. The reduction in the magnitude of the nuclear fuel is small relative to the increased power output capability available due to the differential peak power limits and the increased enrichment. It will also be appreciated that other peak power limit differentiations may be provided within the fuel bundle dependent on lattice position within the bundle. For example, the fuel rods adjacent the one or more water rods of the bundle have been observed to operate at powers higher than other interior rods although at reduced powers relative to the edge rods. Thus, the foregoing described principles may apply to those rods adjacent the one or more water rods within the bundle and hence their peak power limit may be raised similarly by reducing the nuclear fuel content within those rods as aforedescribed. Further differentiations may also be provided dependent upon lattice position. To summarize, the present invention provides peak power limit differentiation among various fuel rods in the fuel bundle dependent upon lattice position. To provide high value differentiation, a higher peak power limit is provided for the edge or peripheral fuel rods which typically have higher power outputs than the interior rods as compared with the peak power limit of the interior rods which results in enhanced bundle power output capability. This is manifested by decreasing the magnitude of nuclear fuel in the edge or peripheral rods while raising their peak power limit, thereby increasing the margin and enabling increased overall power output for that bundle. The edge or peripheral rods can also have increased enrichment to obtain enhanced power output capability. Other lesser value peak power limit differentiations within the fuel bundle may also be provided. Of course, the peak power limits are determined prior to the first fission chain reaction of the nuclear fuel bundle in the nuclear reactor. While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
	description	The present invention relates to a radiotherapeutic apparatus. A collimator marketed by Nomos Corporation; US., consist of two rows of binary collimators called vanes. Each vane can be in or out and typically covers an area of 1 cm by 1 cm when projected to the patient. These two rows cover an area of 20 cm by 2 cm. Usually the collimator is rotated around the patient and the vanes moved in and out of the radiation field in order to modulate the intensity of the radiation and create the desired dose distribution inside the patient. The system is illustrated in U.S. Pat. No. 5,596,619. At the completion of the irradiation, one longitudinal slice of the patient has been irradiated and the patient is moved longitudinally (indexed) to the position for the next slice. This motion needs to be very precise as inaccuracies lead to over or under dosages in the tumour and might jeopardise the patient's outcome. The present invention provides a radiotherapeutic apparatus comprising a source of radiation, a collimator comprising a plurality of moveable elements arranged to selectively modulate radiation emitted by the source, the collimator being moveable along an arc centred substantially on the radiation source. Thus, the collimator can sweep an arc whilst modulating the radiation. This would be done while the gantry and patient are stationary. A new beam orientation is then selected by moving the gantry on which the source and collimator are provided, and potentially the couch on which the patient is supported, and then another sweep is performed. This operation would be performed a number of times. The principal advantage of this technique is there are no junction effects, due to the continuous movement of the collimator. This should prevent any unwanted under or over dosages. In the Nomos system, the longitudinal resolution of the indexing method is inherently limited by the length of the vanes in that direction (half the index step). With the present invention, the vanes can be opened and shut at any time in the sweep, removing this limitation. Furthermore the positions at which the vanes are opened and shut can be independent for the different beam orientations. As the indexing has had to be so precise in known arrangements, this has often required that the operators enter the room. This is in principle undesirable for health and safety reasons. According to the present invention, the mechanism will be part of the collimator of the linac such user intervention will not be required. The known indexing technique forces all incident beam orientations to have the same couch angle—typically zero. This limits the scope for optimisation of beam orientations. It has been shown that allowing other orientations in general improves the optimisation of the dose distribution. The present invention does not have these constraints and all beam orientations normally available for radiotherapy can be used. The collimator used in the invention can be similar to that of the Nomos system, ie one comprising a plurality of beam segments each associated with a moveable element adapted to selectively block the beam segment. Typically, the beam segments are arranged in an array, such as a linear array or a 2*n array. The moveable elements can take up one of two available positions, one located within the array and thus adapted to block the beam segment, and one located outside the array. In this case, it is preferred that the collimator is adapted to move transverse to both the beam axis and the array length. The collimator can also be a multi-leaf collimator. These comprise elongate leaves which can be moved into the path of the beam by a desired length. Thus, each leaf modulates the width of the beam at that point. Typically, two arrays of leaves are provided, one on either side of the beam, each having a plurality of leaves disposed in a generally parallel arrangement. In this case, it is preferred that the collimator moves transverse to both the beam axis and the length of the leaves. Thus, a particular non-treated location on the patient will be shielded by a succession of leaves as the collimator moves, each leaf moving as the collimator moves thereby following the outline of the volume to be treated. MLCs are now extensively used for intensity modulated therapy. In general the trajectory of each leaf is modified to create a dose fluence that creates the desired dose distribution inside the patient. In known systems, there is no possibility of optimising the dose distribution in the direction orthogonal to the leaf travel. This can only be improved by MLCs with thinner leaves and in general more leaves (to cover the same treatment field size). According to aspects of the invention, an MLC is swept in (for example) an arc in a direction orthogonal to the leaf travel. While the MLC is being swept the leaves move in a trajectory which allows the cumulative fluence to the patient to be modulated. With known arrangements, a particular point in the patient is always shielded by a particular leaf pair. According to the invention, this same point would be successively shielded by a number of leaf pairs. The number of leaf pairs will determine the resolution of the modulation and will typically be between 5 and 10. This sweep would then be repeated for a number of beam orientations. In a system according to the present invention employing a multi-leaf collimator, the dose distribution can be optimised according to methods used in Intensity Modulated Arc Therapy (IMAT) techniques. This arrangement according to the present invention is advantageous as compared to existing MLC techniques since the resolution in the direction of the sweep is unlimited, as the sweep is continuous. The resolution in the direction of the leaves of an MLC is already unlimited, and thus the present invention can give a free choice of resolution in both axes. In addition, the field size in the direction of motion is not limited by the number of leaves and their width. This simplifies the construction of the collimator. Further, the efficiency of the device, i.e. the ratio between radiation delivered by the linac and dose absorbed by the patient is much higher than the known Nomos collimator (described above) as a much larger area is being treated at any one time. Existing multi-leaf collimators exhibit edge effects associated with the junctions between leaves—so called ‘tongue and groove’. These can be avoided through the present invention. Multi-leaf collimators also leak slightly between leaves, known as interleaf leakage. According to the present invention, this leakage is spread out so that all areas only receive the average leakage. Thus, no one area receives an exceptional leakage. FIG. 1 shows a typical multi-leaf collimator. A frame 10 carries a number of individual leaves 12, 14 etc. Each of these is supported horizontally within the frame and can move into and out of the field of irradiation which the frame defines. In general, each leaf is driven by a motor and its position is detected for confirmation. The leaves are arranged in a pair of opposing arrays designated generally as 16 and 18 and thus the two sides of the field can be defined. In known arrangements, the resolution in the direction of the leaves is thus effectively unlimited, whilst the resolution orthogonal to the direction of the leaves is limited by the width of the leaves. This leads to a compromise leaf width, in that a decreased leaf width results in greater resolution, but also to additional engineering difficulties in supporting narrow leaves, and driving each leaf individually to an acceptable accuracy. In general, the use of extremely narrow leaves also tends to result in a physically small collimator which provides only a small aperture. FIG. 2 shows a binary collimator 20 similar to the Nomos system with a 2×16 array. Other collimators (not shown) limit the field of the radiation to that of the 2×16 array. A plurality of individual pixel elements 22 are moveable into and out of the array, in this example pixel 24 being within the array and pixel 26 being outside. Thus, when the pixel is within the array the radiation is blocked at that point, and when it is outside the array, radiation can pass through that part of the collimator. As shown in FIG. 2, the plurality of individual pixels can be inserted into the array or withdrawn to one side of the array (such as pixel 26) thereby defining a space 28 in which radiation can pass. FIG. 3 shows schematically the arrangement according to the present invention. A radiation source 50 is provided and would normally be held in a gantry above a patient support table (not shown) below the radiation source. A collimator 52 is also provided beneath the source 50, and can be as per FIG. 1 or FIG. 2, for example. The collimator 52 is supported so that it can swing about an arc 54 which is centred on a radiation source 50. Thus, notwithstanding movement of the collimator along its arc 54, the individual elements of the collimator (pixels or leaves) will remain focussed on the source 50. As the collimator 52 sweeps along the arc 54, it will selectively irradiate different parts of the patient. During movement, the leaves 12 of the collimator according to FIG. 1 or the pixels 22 of the collimator according to FIG. 2 can be adjusted and operated so as to project the desired radiation beam shape on to the patient. As this is a smooth movement, it avoids edge artifacts and indexing difficulties as set out above. It will be appreciated that many variations can be made to the above-described embodiments without departing from the present invention.
	claims	1. An apparatus comprising:a pressurized water reactor (PWR) including a cylindrical pressure vessel with its cylinder axis oriented vertically, a cylindrical central riser disposed within the pressure vessel, so that a downcomer annulus is formed therebetween, a nuclear reactor core disposed in the cylindrical pressure vessel, and a separator plate disposed in the cylindrical pressure vessel that separates the pressure vessel to define an integral pressurizer volume disposed above the separator plate and a reactor vessel portion containing the nuclear reactor core disposed below the separator plate; anda reactor coolant pump including:a pump assembly including a pump motor, an impeller, and a vertical driveshaft that operatively connects the pump motor and the impeller as a pump assembly, anda pump diffuser configured to receive the impeller, the pump diffuser not being secured with the pump assembly,wherein the reactor coolant pump is mounted on the cylindrical pressure vessel of the PWR with the impeller disposed in the pump diffuser above the nuclear reactor core and adjacent both the separator plate and the top end of the central riser so that the impeller is disposed at a turnaround point of a primary coolant flow, with at least a portion of the pump motor being disposed above the separator plate and with no portion of the reactor coolant pump passing through the integral pressurizer volume,wherein at the turnaround point of the primary coolant flow reverses direction from an upward flow through the central riser to a downward flow through the downcomer annulus. 2. The apparatus of claim 1, wherein the pump motor is disposed above the impeller. 3. The apparatus of claim 1, wherein the reactor coolant pump is mounted on the cylindrical pressure vessel of the PWR with the impeller and pump diffuser disposed in the reactor vessel portion below the separator plate. 4. The apparatus of claim 1, wherein the pump diffuser is mounted on and supported by a support plate disposed below the separator plate, and wherein the impeller is not supported by the pump diffuser and is not supported by the support plate. 5. The apparatus of claim 4, wherein the support plate separates the suction and discharge sides of the pump diffuser. 6. The apparatus of claim 1, wherein the reactor coolant pump is mounted on the cylindrical pressure vessel of the PWR with the drive shaft passing through a vessel penetration of the cylindrical pressure vessel that is large enough for the impeller to pass through. 7. The apparatus of claim 6, wherein the vessel penetration of the cylindrical pressure vessel on which the reactor coolant pump is mounted with the drive shaft passing through is too small for the pump diffuser to pass through.
	claims	1. A method of packaging a nuclear reactor vessel for decommissioning and removal, comprising the steps of: installing reactor vessel closure plates onto the vessel; injecting concrete into the vessel; installing a first shielding ring around main nozzles of the vessel; enclosing the vessel with a second shielding ring; welding longitudinal seams of the first shielding ring; welding longitudinal seams of the second shielding ring; welding the second shielding ring to the first shielding ring; placing the vessel on shipping cradles; and tightening a longitudinal restraint mechanism to the vessel. 2. The method of packaging a nuclear reactor vessel according to claim 1 , wherein the concrete is wet, low density cellular concrete. claim 1 3. The method of packaging a nuclear reactor vessel according to claim 1 , wherein the concrete has a density between 0.721 g/cm 3 to 1.041 g/cm 3 . claim 1 4. The method of packaging a nuclear reactor vessel according to claim 1 , further comprising the step of preparing the concrete on-site with foaming agents and curing additives. claim 1 5. The method of packaging a nuclear reactor vessel according to claim 1 , further comprising the step of circulating air into the vessel to remove heat from inside the vessel. claim 1 6. The method of packaging a nuclear reactor vessel according to claim 5 , wherein the step of circulating air into the vessel is performed prior to the step of injecting the concrete into the vessel. claim 5 7. The method of packaging a nuclear reactor vessel according to claim 1 , further comprising the step of allowing the vessel to vent and cool. claim 1 8. The method of packaging a nuclear reactor vessel according to claim 1 , further comprising the steps of: claim 1 removing the closure plates; verifying that the vessel includes a requisite amount of the concrete; verifying that there are no empty spaces in the vessel; and confirming that no free standing water is in the vessel. 9. The method of packaging a nuclear reactor vessel according to claim 1 , wherein the first shielding ring is steel and is externally installed around the main nozzles of the vessel. claim 1 10. The method of packaging a nuclear reactor vessel according to claim 9 , wherein the second shielding ring has substantially the same composition as the first shielding ring and is externally installed around a core area of the vessel. claim 9 11. The method of packaging a nuclear reactor vessel according to claim 1 , further comprising the steps of: claim 1 lowering the vessel into the second shielding ring; and mechanically fastening the second shielding ring to the vessel. 12. The method of packaging a nuclear reactor vessel according to claim 1 , further comprising the steps of: claim 1 using temporary mechanical fasteners to hold the first and second shielding rings in place; and removing the temporary mechanical fasteners after the first and second shielding rings are welded. 13. The method of packaging a nuclear reactor vessel according to claim 1 , wherein the closure plates are welded to the vessel. claim 1 14. The method of packaging a nuclear reactor vessel according to claim 1 , further comprising the step of installing impact limiters on each end of the vessel. claim 1
	claims	1. An X-ray tube comprising:an electron emission unit comprising a cold cathode,wherein the electron emission unit is divided into a first region A and a second region B, andwherein the electron emission unit is formed in a square shape, and the first region A comprises a square in a center of the electron emission unit that it inclined at 45 degrees to edges of the emission unit, and the second region B comprises four corners of the electron emission unit surrounding the first region A;an anode unit comprising a target unit disposed opposite to the electron emission unit, with which electrons emitted from the electron emission unit collide;a focus structure disposed between the electron emission unit and the target unit disposed on a surface of the anode unit that is opposed to the electron emission unit;a first transistor TA connected to the first region A;a second transistor TB connected to the second region B; anda controller configured to turn ON/OFF the first region A and the second region B independently by selectively maintaining ON and OFF gate-cathode potentials in the first transistor TA and the second transistor TB respectively, andwherein collision regions at the anode unit of electron beams emitted from the first region A and the second region B substantially coincide with each other. 2. The X-ray tube according to claim 1, whereinthe first region A comprises a center region, andthe second region B comprises one or more peripheral regions surrounding the center region. 3. The X-ray tube according to claim 2, wherein an area of the center region and a total area of the one or more peripheral regions are substantially equal to each other.
	summary
	claims	1. A product, comprising:an array of three dimensional structures, wherein each of the three dimensional structures comprises a semiconductor material;a continuous cavity region defined by sidewalls of the three dimensional structures, the cavity region extending along an entire height of the three dimensional structures, the height being defined between top and bottom ends of the respective three dimensional structure;a first material in direct contact with at least one surface of the semiconductor material of each of the three dimensional structures, wherein the first material fills at least 25% of a volume of the cavity region, wherein the first material includes a first radioisotope configured to provide high energy particle and/or ray emissions; anda second material configured to provide high energy particle and/or ray emissions, wherein the second material includes a second radioisotope which forms a layer that is deposited on at least one portion of the first material;wherein the second radioisotope is different from the first radioisotope;wherein the first and second radioisotopes are in direct contact with each other. 2. The product of claim 1, wherein the semiconductor material is selected from a group consisting of: silicon, silicon carbide, gallium arsenide, indium phosphide, icosahedral boride, and gallium nitride. 3. The product of claim 1, wherein each of the three dimensional structures comprises an aspect ratio of less than about 100:1, wherein the first material is in a plane of deposition of the three dimensional structures. 4. The product of claim 1, wherein the first material has a thickness in a range of about 50 to about 500 microns, wherein the second material forms a layer that is deposited directly on at least one portion of the first material. 5. The product of claim 1, wherein the first material comprises a radioisotope selected from a group consisting of: 148Gd, 238Pu, 244Cm, 243Am, 241Am, 106Ru, and 232U. 6. The product of claim 1, wherein the first material comprises a tritiated metal. 7. The product of claim 1, wherein the second material comprises a radioisotope selected from a group consisting of: 148Gd, 238Pu, 244Cm, 243Am, 241Am, 106Ru, and 232U. 8. The product of claim 1, further comprising one or more additional materials positioned above at least one portion of the second material, wherein each of the one or more additional materials are configured to provide high energy particle and/or ray emissions. 9. The product of claim 8, wherein each of the one or more additional materials comprises a radioisotope that is independently selected from a group consisting of: 148Gd, 238Pu, 244Cm, 243Am, 241Am, 63Ni, 106Ru, and 232U. 10. A method, comprising:forming an array of three dimensional structures, wherein each of the three dimensional structures comprises a semiconductor material; anddepositing a solid first material on at least one surface of the semiconductor material of each of the three dimensional structures,wherein the first material fills at least 25% of a volume of a cavity region between each of the three dimensional structures,wherein a plane of deposition of the semiconductor material of the three dimensional structures extends through the first material,wherein the first material includes two layers,wherein the first layer includes a first radioisotope configured to provide high energy particles and/or ray emissions,wherein the second layer includes a second radioisotope configured to provide high energy particles and/or ray emissions,wherein the second radioisotope is different from the first radioisotope,wherein the first and second radioisotopes are in direct contact with each other. 11. The method of claim 10, wherein the semiconductor material is selected from a group consisting of: single crystal silicon, amorphous silicon, silicon carbide, gallium arsenide, indium phosphide, gallium nitride and an icosahedral boride. 12. The method of claim 10, wherein the first material comprises a radioisotope selected from a group consisting of: 148Gd, 238Pu, 244Cm, 243Am, 241Am, 106Ru, 233U, 232U, 210Po, and a tritiated metal. 13. The method of claim 10, wherein forming the array of three dimensional structures includes at least one process selected from the group consisting of: wet chemical etching, ion beam etching, and plasma etching, wherein the cavity region between each of the three dimensional structures of the array is a continuous cavity region defined by sidewalls of the three dimensional structures, the cavity region extending along an entire height of the three dimensional structures, the height being defined between top and bottom ends of the respective three dimensional structure. 14. The method of claim 10, further comprising applying a second material above the first material, wherein the second material is configured to provide high energy particle and/or ray emissions therefrom to the same sides of the three dimensional structures as the first material, wherein the second material forms a layer that is deposited directly on at least one portion of the first material. 15. The method of claim 14, further comprising applying one or more additional materials above at least one portion of the second material, wherein each of the one or more additional materials is configured to provide high energy particle and/or ray emissions therefrom to the same sides of the three dimensional structures as the second material.
	description	This application claims the benefit of U.S. Provisional Application No. 61/625,457, filed Apr. 17, 2012, titled “INSTRUMENTATION AND CONTROL (I&C) ARCHITECTURE AND MAIN CONTROL ROOM FOR CONTROLLING A NUCLEAR REACTOR FACILITY”. This application claims the benefit of U.S. Provisional Application No. 61/625,895, filed Apr. 18, 2012, titled “MAIN CONTROL ROOM FOR A NUCLEAR POWER PLANT WITH TWO REACTOR UNITS”. U.S. Provisional Application No. 61/625,457, filed Apr. 17, 2012, is hereby incorporated by reference in its entirety into the specification of this application. U.S. Provisional Application No. 61/625,895, filed Apr. 18, 2012, is hereby incorporated by reference in its entirety into the specification of this application. The following relates to the nuclear reactor arts, nuclear power generation arts, nuclear reactor control arts, nuclear reactor human-machine interface (HMI) arts, nuclear reactor control arts, and related arts. The human-machine interface (HMI) and control systems of a nuclear power plant should be ergonomic to reduce likelihood of human operator error. These systems should also be designed to minimize likelihood of mechanical or electronic failure, and to be defensible against physical assault. While computer-based control systems have advantages, the use of computer systems is balanced against disadvantages including intangibility and the potential for malicious cyber-assault. In existing nuclear power plants, these design constraints are accommodated by providing a control room for the nuclear power plant. An operator at the controls (OATC) deployed in the central control room is responsible for all aspects of operation of the nuclear island, which houses the nuclear reactor unit which includes the pressure vessel containing the nuclear reactor core comprising fissile material (e.g. 235U) immersed in primary coolant water and ancillary components such as a pressurizer, reactor coolant pumps (RCPs), and a control rod drive system including control rods operated by control rod drive mechanisms (CRDMS). In the case of a boiling water reactor (BWR), primary coolant is directly boiled to generate steam for operating the plant turbine. In a pressurized water reactor (PWR), primary coolant in liquid form flows through a steam generator to boil secondary coolant so as to generate the operating steam. The steam generator may be located external to the reactor unit, or inside the pressure vessel of the reactor unit (called an “integral PWR”). The nuclear reactor unit and external steam generator (if present) are housed in a radiological containment structure, usually made of steel or steel-reinforced concrete, and a reactor service building houses both the containment structure and the control room. Alternatively, the control room may be in a separate building located close to (e.g. adjacent) the reactor service building. From the control room, the OATC has operational control of all safety and non-safety systems related to operating the nuclear reactor unit. These include (by way of illustrative example): reactor pressure and temperature control systems (e.g., CRDMs, pressurizer, et cetera); the emergency core cooling system; various water systems (e.g. component cooling water servicing pumps and other water-cooled components, circulating water servicing a condenser downstream of the turbine, a reactor coolant inventory/purification system); the steam turbine control system, the electrical generator control system, and electrical power distribution systems. Some of these components, such as the electrical generator, are not actually part of the nuclear island, but their operation is critical to safe operation of the nuclear island and hence are under control of the OATC. Until recently, analog reactor control systems were predominantly used. Analog systems advantageously provide hard-wired connections and tangible switches, buttons, dials, annunciator lights, and other tangible user interface elements, and are impervious to cyber attack. The tangible nature of the analog control components facilitates diagnosis of any control system failure. The threat of malicious physical tampering is mitigated by locating the control room in the reactor service building with the nuclear reactor unit, which reduces cable run lengths. Digital, i.e. computer-based control systems are increasingly being used. In such cases, the digital communication systems are generally on an isolated digital data network (e.g., not connected with the Internet or to any local area network employed for general plant business operations, so as to mitigate the threat of cyber attack). The digital data network is typically a hard-wired network so as to enhance tangibility, although the use of wireless communication is contemplated. Some regulatory jurisdictions require an analog system backing up any digital control systems. The nuclear power plant includes numerous other control systems that are unrelated to, or tangentially related to, safe operation of the nuclear island. These include, by way of illustrative example: electrical switchyard interfacing with the external power grid; utility system such as demineralized water (DW); water makeup systems; environmental monitoring; fire detection systems; and so forth. The impact of these systems on safe operation of the nuclear island is delayed or nonexistent. Some of these non-safety systems may be under control of the OATC inside the control room, while others may be under control of other plant personnel located elsewhere. Overall coordination of plant operations is generally under the control of a Senior (or Supervisory) Reactor Operator (SRO), who provides on-site interfacing between the OATC, other plant operators, and entities outside the nuclear power plant (e.g., external electrical, water, and other utilities, the general public, and so forth). In this supervisory role, the SRO is typically located in a business-style office, and communicates with the OATC and other plant operators via telephone, although the SRO may be mobile and, for example, go to the control room when appropriate. In the United States and most other jurisdictions, plant control is regulated, e.g. by the Nuclear Regulatory Commission (NRC) in the United States. In the NRC regulatory framework, the OATC and the SRO must be licensed by the NRC to operate the specific nuclear power plant at which they are employed. In practice, several OATCs, as well as the SRO, are required to be on-site at all times, and all licensed operators are required to partake in ongoing training including simulation time. The nuclear power plant must therefore employ several dozen OATCs in order to have sufficient capacity for full-time 24-hour operation. Some nuclear power plants include two or more nuclear reactor units. In such cases, each nuclear power plant has its own control room with cabling between the control room and the controlled nuclear reactor unit, and each reactor unit is serviced by its own ancillary water, electrical, and other utility systems. Each reactor unit has its own SRO, and there may be a managing SRO overseeing all nuclear reactor units of the power plant. Disclosed herein are improvements that provide various benefits that will become apparent to the skilled artisan upon reading the following. In accordance with one aspect, a control room is disclosed for monitoring and controlling a nuclear power plant including a first nuclear reactor unit and a second nuclear reactor unit. The control room comprises: a central workstation providing monitoring capability for both the first nuclear reactor unit and the second nuclear reactor unit; a first operator at the controls (OATC) workstation in front of and to one side of the central workstation providing monitoring and control capabilities for the first nuclear reactor unit but not for the second nuclear reactor unit; and a second OATC workstation in front of and to the other side of the central workstation providing monitoring and control capabilities for the second nuclear reactor unit but not for the first nuclear reactor unit. The central workstation, the first OATC workstation, and the second OATC workstation are disposed in the control room. In some embodiments the central workstation does not provide control capabilities for the first nuclear reactor unit and does not provide control capabilities for the second nuclear reactor unit. In accordance with another aspect, a nuclear power plant includes a first nuclear reactor unit including a nuclear reactor core comprising fissile material disposed in a pressure vessel, a second nuclear reactor unit including a nuclear reactor core comprising fissile material disposed in a pressure vessel; and a control room as set forth in the immediately preceding paragraph. In accordance with another aspect, a control room is disclosed for monitoring and controlling a nuclear power plant including a first nuclear reactor unit and a second nuclear reactor unit. The control room comprises: a central workstation providing monitoring capability for both the first nuclear reactor unit and the second nuclear reactor unit; a first operator at the controls (OATC) workstation providing monitoring and control capabilities for the first nuclear reactor unit but not for the second nuclear reactor unit; a second OATC workstation providing monitoring and control capabilities for the second nuclear reactor unit but not for the first nuclear reactor unit; and a common control workstation providing monitoring and control capabilities for systems serving both the first nuclear reactor unit and the second nuclear reactor unit. The central workstation, the first OATC workstation, the second OATC workstation, and the common control workstation are disposed in the control room. In accordance with another aspect, a control room is disclosed for monitoring and controlling a nuclear power plant including one or more nuclear reactor units. The control room comprises: a central workstation providing monitoring capability for the one or more nuclear reactor units; one or more operator at the controls (OATC) workstations, each OATC workstation providing monitoring and control capabilities for a corresponding one of the one or more nuclear reactor units; and a non-safety control workstation providing monitoring and control capabilities for non-safety systems servicing the one or more nuclear reactor units wherein a failure of any non-safety system controlled by the non-safety control workstation does not require intervention of an OATC for at least a minimum time interval TCC. The central workstation, the one or more OATC workstations, and the non-safety control workstation are disposed in the control room. In some embodiments TCC has a value greater than or equal to one hour. In accordance with another aspect, a control room as set forth in either one of the two immediately preceding paragraphs further includes a data network providing: one-way communication from each OATC workstation to the common or non-safety control workstation; one-way communication from each OATC workstation to the central workstation; bidirectional communication between each OATC workstation and its corresponding nuclear reactor unit; and no communication between the common or non-safety control workstation and any of the one or more nuclear reactor units. In some embodiments the data network provides no communication between the central workstation and any of the one or more nuclear reactor units. In some embodiments the control room further includes: one or more manual safety panels (MSPs) corresponding to the one or more nuclear reactor units, each MSP being in bidirectional analog communication with its corresponding nuclear reactor unit; wherein the MSPs are disposed with the central workstation, the one or more OATC workstations, and the common or non-safety control workstation in the control room. Disclosed herein are improved control room embodiments that are designed to be operated by a reduced number of licensed operators (as few as three licensed operators for a nuclear reactor unit, in some embodiments). The disclosed control room embodiments also enhance communication between licensed operators at the controls (OATCs), the Supervisory (or Senior) Reactor Operator (SRO), and other plant operators. As used herein, the OATC is a licensed operator that is licensed by the NRC (or the governing nuclear regulatory agency of the applicable jurisdiction) to operate the nuclear reactor unit under control of the OATC. The SRO is also a licensed operator, and also meets any other regulatory requirements for serving as a Supervisory (or Senior) Reactor Operator. All other plant operators may be licensed or unlicensed. An unlicensed plant operators is sometimes referred to herein as a “Non-licensed Reactor Operator” (NRO). It is to be understood that these operators may have various titles in various jurisdictions and/or at various nuclear power plants. The disclosed control room embodiments are scalable to nuclear power plants with one, two, or more nuclear reactor units. With reference to FIG. 1, a nuclear power plant with two nuclear reactor units 1 is shown, which in the illustrative embodiment are small modular reactor (SMR) units. An SMR is typically considered to be a nuclear reactor unit having an electrical power output of 300-500 MWe or lower. The illustrative configuration with two reactor units 1 is sometimes referred to a as a “twin-pack”. Where it is useful to distinguish between the two reactor control units 1, they are referred to herein as “SMR #1” (the left-hand unit 1 shown in FIG. 1) and “SMR #2” (the right-hand unit 1 shown in FIG. 1). Each of the illustrative reactor units 1 (shown in perspective view in partial section) is SMR of the pressurized water reactor (PWR) type, and includes a pressure vessel 2 comprising an upper vessel and a lower vessel joined by a mid-flange. The pressure vessel 2 houses a nuclear reactor core 4 comprising fissile material, e.g. 235U immersed in primary coolant water. Reactivity control is provided by a control rods system that includes control rod drive mechanisms (CRDMs) 6 and control rod guide frame supports 8. The illustrative CRDMs 6 are internal CRDMs disposed inside the pressure vessel and including CRDM motors 6m disposed inside the pressure vessel; however, external CRDMs with motors mounted above the pressure vessel and connected via tubular pressure boundary extensions are also contemplated. The pressure vessel 2 of the operating PWR contains circulating primary coolant water that flows upward through the nuclear reactor core 4 and through a cylindrical central riser 10, discharges at the top of the central riser 10 and flows back downward through a downcomer annulus 12 defined between the pressure vessel and the central riser to complete the primary coolant circuit. In the illustrative PWR, primary coolant circulation is driven by reactor coolant pumps (RCPs) 14 which may be located where illustrated in FIG. 1 or elsewhere (including a contemplated variant employing internal RCPs located inside the pressure vessel); moreover, natural circulation or the use of internal RCPs disposed inside the pressure vessel is also contemplated. Pressure inside the pressure vessel of the illustrative PWR is maintained by heating or cooling a steam bubble disposed in an integral pressurizer volume 16 of an integral pressurizer 17; alternatively, an external pressurizer can be connected with the pressure vessel by piping. Each illustrative PWR 1 is an integral PWR in which a steam generator (or plurality of steam generators) 18 is disposed inside the pressure vessel 2, and specifically in the downcomer annulus 12 in the illustrative PWR; alternatively, an external steam generator can be employed. In the illustrative integral PWR, secondary coolant in the form of feedwater is input to the steam generator 18 via a feedwater inlet 20, and secondary coolant in the form of generated steam exits via a steam outlet 21. In the alternative case of an external steam generator, the ports 20, 21 would be replaced by primary coolant inlet and outlet ports feeding the external steam generator. Each PWR 1 is disposed inside its own primary containment 22, which is suitably a steel structure, steel-reinforced concrete structure, or the like. (Thus, there are two separate primary containment structures 22 in the illustrative two-pack nuclear power plant). It is to be understood that the illustrative nuclear power plant of FIG. 1 is an illustrative example. The disclosed nuclear power plant control room designs are suitably employed in conjunction with various nuclear reactor units, such as an integral PWR (as illustrated), or with a PWR employing an external generator (typically housed inside the main containment), or with a boiling water reactor (BWR) that does not include a steam generator. Although the illustrative plant of FIG. 1 is a two-pack, illustrative four-pack embodiments are also described herein, and it is to be understood that the disclosed control room embodiments are suitably used in conjunction with a nuclear power plant having one nuclear reactor unit, two nuclear reactor units, three nuclear reactor units, four nuclear reactor units (also illustrated), five nuclear reactor units, six nuclear reactor units, or so forth. The remainder of the nuclear power plant is not illustrated in FIG. 1. In a typical configuration, the steam output by the steam generator 18 of each PWR 1 (or output by a BWR directly) drives a steam turbine that in turn drives an electric generator that feeds an external electrical power grid through various electrical power lines, transformers, or so forth. The nuclear power plant also includes auxiliary systems such as an emergency core cooling (ECC) system, a reactor coolant system (RCS, including the primary coolant inside the pressure vessel 2 along with the pressurizer 16, 17 and other ancillary components), a reactor coolant inventory/purification system (RCIPS), various house electrical systems, backup electrical power (e.g. diesel generators and/or batteries), various cooling/chilled water systems, makeup water supplies, and so forth. Again, these components are not shown in FIG. 1. Some of these systems are dedicated to a single reactor unit 1—for example, there is a separate turbine/generator system for each reactor unit 1. On the other hand, some of these systems are shared in common by both SMR #1 and SMR #2. With reference to FIG. 2, some principal systems of the nuclear power plant of FIG. 1 are listed. In FIG. 2, these systems are categorized as: “Plant Protection” systems, “Plant Control” systems, “Common Control” systems, or “Plant Management” systems. The “Plant Protection” and “Plant Control” systems are dedicated to a single reactor unit—in other words, for the illustrative two-pack plant there are two instances of each of these systems, one servicing SMR #1 and the other servicing SMR #2. (By extension, in a four-pack plant there would be four instances of such systems, and so forth). The “Common control” and “Plant management” systems are typically (although not necessarily) shared between SMR #1 and SMR #2 —in other words, there typically is a single instance of each of these systems, which services both reactor units SMR #1 and SMR #2. As will be discussed, however, the “Common control” systems can be defined on a basis of a minimum time interval before the OATC must address a failure in a system of the “Common control” category. It will be noticed that there is some overlap between the “Plant Protection” and “Plant Control” systems—for example, the Reactor Coolant System (RCS) is listed under both “Plant Protection” and “Plant Control”. These dual-listed systems provide both plant control and plant protection functions. The RCS, for example, performs a plant control function in that control of primary coolant pressure and temperature is used to adjust the thermal power generated by the reactor unit during normal operation; additionally, however, the RCS serves a plant protection function in that it absorbs heat from the nuclear reactor core and transfers it to the steam generator (in the illustrative case of a PWR; alternatively, in a BWR the primary coolant directly boils and conducts heat away as primary coolant steam). Most systems listed in FIG. 2 are well known systems that are commonly present in existing nuclear power plants. The listed auxiliary condenser (CNX), however, is a non-standard component contemplated for inclusion in the B&W mPower™ small modular reactor design. This auxiliary condenser is located outside containment (e.g., a roof-mounted condenser) and is air-cooled by battery-operated fans. The auxiliary condenser is connected with the steam generator 18, which is internal to the pressure vessel in the mPower™ design (i.e., an integral PWR), so that it provides passive cooling using secondary coolant trapped in the steam generator when main feedwater and steam line valves are shut. The CNX is usable in a protective role, for example coming on-line to dissipate heat if the RCS temperature exceeds a safety threshold. The CNX is also usable in a plant control role, for example providing more rapid cool down during reactor shutdown for refueling. Accordingly, the CNX is listed under both “Plant Protection” and “Plant Control” categories. The categorization of systems shown in FIG. 2 is not merely pedagogic—rather, these system categories are used in the design of the disclosed control room embodiments. It is recognized herein that those systems that are shared between SMR #1 and SMR #2 (or more generally, that are shared between two or more nuclear reactor units) are not of a safety-critical nature. For example, the regulatory framework of the NRC requires that safety-critical systems not be shared amongst nuclear reactor units unless it can be shown that the sharing does not significantly impair their ability to perform their safety functions including, in the event of an accident in one unit, shutdown and cool down of the remaining units. Thus, any system that is shared between SMR #1 and SMR #2 (or, more generally, that is shared between two or more reactor units) is suitably categorized as a “Common Control” or “Plant Management” system. The “Common Control” and “Plant Management” systems do not need to be under the control of the OATC, and the “Plant Management” systems are generally monitoring-only systems (without control capability). The “Common control” category can be expanded to encompass some systems that are reactor unit specific. For example, consider the plant water make-up (PWM) system, which is listed in the “Common Control” category. Loss of this system does not pose an immediate safety concern requiring action by the OATC of either SMR #1 or SMR #2, because the reactor coolant inventor (RCI) contains sufficient purified water for maintaining the primary coolant level in the reactor vessel 2 for some minimum time interval. (Appropriately, the RCI is listed under the “Plant Control” category and is supervised by the OATC.) However, if the plant make-up water system remains unavailable for an extended period of time, then eventually both SMR #1 and SMR #2 will need to be shut down. In view of this, nuclear regulations generally allow the PWM system to be shared amongst two (and possibly more) reactor units. But, these observations remain true even if the PWM system is segregated into separate PWM systems for SMR #1 and SMR #2. The principled rationale for placing the PWM system under the “Common control” category is not that it is shared between SMR #1 and SMR #2 —rather, the principled rationale for this categorization is that any failure of the PWM system does not need to be addressed by the OATC for some minimum time interval. Accordingly, in some embodiments the basis for categorizing a system in the “Common control” category is as follows: Any failure of the system does not require attention of the OATC for at least a minimum time interval TCC. It will be readily recognized that decreasing TCC allows more systems to be classified in the “Common control” category. However, decreasing TCC also means that a failure of a “Common control” system may require OATC intervention more quickly. In some embodiments, a time interval of one hour is used (i.e. TCC=1 hour), and this criterion was used in generating the categorization shown in FIG. 2. By setting the minimum time interval TCC to a value greater than or equal to one hour, it is generally assured that the OATC will not need to intervene in typical events which can be handled by the NLO. In view of the foregoing, the “Common Control” category is sometimes referred to herein as the “Non-safety Control” category. In view of the foregoing, the disclosed control room embodiments assign the systems in the “Plant Protection” and “Plant Control” categories to the OATC, while systems in the “Common Control” category are assigned to a different plant operator. Conditional upon approval by the governing nuclear regulatory agency, the plant operator in charge of the “Common Control” systems can be a non-licensed operator (NLO), although it is contemplated to employ a licensed operator for these tasks (e.g., to conform with regulations, if applicable, and/or to provide an additional licensed operator on-site for redundancy purposes). Systems under the “Plant Management” category are plant supervisory monitoring tasks that fall under control of the SRO. The disclosed control room embodiments are also designed to enhance communications between operators. It is useful for the OATC of the (illustrative) two SMR units, the SRO, and the other plant operators to be in efficient communication with one another. In existing nuclear power plants, such communication is adversely impacted by physical separation of the plant operators. The OATC is necessarily stationed in the control room. However, conventionally the SRO is stationed elsewhere, for example in a plant supervisor's office. The various other plant operators are distributed through the plant, performing various functions. Communication via telephone is helpful, but telephonic communication limits the ability of the SRO to oversee safety-critical functions performed by the OATC. The SRO can travel to the control room to personally oversee operations when appropriate, but this requires travel time, and does not address the possibility that the OATC may fail to recognize a problem that the SRO might have recognized if present. Similarly, telephonic communication of the SRO and/or OATC with other plant operators is less than ideal. With continuing reference to FIGS. 1 and 2 and with further reference to FIG. 3, the OATC for both SMR #1 and SMR #2, as well as the SRO and a senior non-licensed operator (NLO), are all stationed in a control room 30. For illustrative purposes, the walls and ceiling of the control room 30, as well as the containing building, are omitted to reveal the operator stations and principle human-machine interface (HMI) components. It is to be understood that the control room 30 may be housed in the same reactor service building that houses the reactor units 1, or may be housed in a nearby (e.g. adjacent) building. The control room 30 includes a centrally located SRO station 32 (i.e. a central workstation 32) where the SRO is stationed. The SRO station 32 provides monitoring capability for both SMR #1 and SMR #2, and additionally provides monitoring capability for the supervisory monitoring tasks that fall under the “Plant management” category. In some embodiments the SRO station 32 does not provide any control capability for either SMR #1 or SMR #2. In front and to one side (left, in the illustrative example) of the SRO station 32 is a first OATC station 34 where the OATC in charge of SMR #1 is stationed. In front and to the other side (right, in the illustrative example) of the SRO station 32 is a second OATC station 36 where the OATC in charge of SMR #2 is stationed. The OATC stations 34, 36 provide both monitoring and control functions for their respective SMR units. Advantageously, the SRO is stationed in the same control room 30 as the OATCs, and so the SRO and the OATCs can communicate directly, and not via telephone or other intervening hardware. Placement of the OATC stations 34, 36 in front of and to either side of the SRO station 32 facilitates the SRO in supervising the OATCs. The SRO station 32 includes a first one or more video display units (VDUs) 44 on the left side of the station that display monitoring data for SMR #1 also viewed by the OATC at the first OATC station 34. Similarly, the SRO station 32 includes a second one or more VDUs 46 on the right side of the station that display monitoring data for SMR #2 also viewed by the OATC at the second OATC station 36. This corresponding spatial arrangement (i.e., both the OATC station 34 and the monitoring VDUs 44 for SMR #1 on the left; and both the OATC station 36 and the monitoring VDUs 46 for SMR #2 on the right) immediately informs the SRO as to which SMR unit is being observed. Again, the VDUs 44, 46 in some embodiments provide only monitoring capabilities, but not control. On the other hand, the VDUs of the first OATC station 34 provide both monitoring and control capabilities for SMR #1, and similarly the VDUs of the second OATC station 36 provide both monitoring and control capabilities for SMR #2. In some embodiments, the VDUs 44, 46 at the SRO station 32 mirror one or more of the VDUs of the corresponding OATC station 34, 36, and optionally the SRO can select by suitable graphical user interface (GUI) input operations which VDU displays are mirrored. In the illustrative embodiment, monitoring and control employs a digital interface with the VDUs providing the human-machine interface (HMI) for monitoring and (in the case of OATC stations 34, 36) control functionality. For example, the monitoring and control may implemented as a central computer (not shown) accessed via the VDUs. Alternatively, each VDU (or some VDUs) can be implemented as desktop computers interconnected by a digital data network. From a safety standpoint, this can be problematic since digital controls are intangible—they do not include tangible switches, buttons, dials, and so forth having dedicated functions. Instead, a VDU displays what it is programmed to display, and provides input controls (e.g., GUI controls) in accord with the digital programming. If there is a failure in such a control system, it can be difficult to diagnose and remediate. Accordingly, the control room 30 includes a manual safety panel (MSP) 54 for SMR #1 off to the one side (e.g. left) of the SRO station 32, and similarly includes an MSP 56 for SMR #2 off to the other side (e.g. right) of the SRO station 32. The MSPs 54, 56 provide manual controls (e.g., dedicated analog buttons, switches, readout dials, annunciator lights, and so forth) for operating those systems in the “Plant Protection” category for the respective SMR unit. In some embodiments, the MSPs 54, 56 do not provide manual controls for operating those systems that are (only) in the “Plant Control” category, although it is contemplated to provide manual control for some such “Plant Control” only systems via the MSPs. Again, placement of the MSPs 54, 56 at either side of the SRO station 32 provides a natural mnemonic link to the appropriate SMR unit, and also places the MSPs 54, 56 in locations that are readily accessed by either the SRO (who is a licensed plant operator) or the OATC for that SMR unit. The systems in the “Common control” category can be performed by a non-licensed operator (NLO), conditional on authorization by the NRC or other governing nuclear regulatory agency) or by a licensed operator. In the following a NLO is assumed to be in charge of the systems of the “Common control” category. In the control room 30, this NLO is stationed at a NLO station 60 (also referred to herein as a common control station 60 or “Non-safety Control” station 60) located between the OATC stations 34, 36. This placement provides a mnemonic reminder that the functions performed at the NLO station 60 (at least generally) apply to both SMR #1 and SMR #2 (although as noted previously, in some embodiments some systems of the “common control” category may be specific to individual SMR units). One or more additional VDUs 62 at the SRO station 32 may enable the SRO to monitor activities at the NLO station 60. (In some embodiments, these VDUs 62 may be switchable to provide additional VDUs for monitoring activities at one or both OATC stations 34, 36). The NLO station 60 provides both monitoring and control capabilities, but only for the systems of the “Common control” category. The illustrative control room 30 further optionally includes vertical panels 64 that may include various monitoring devices, e.g. VDUs, analog dials, annunciators, or so forth. The vertical panels 64 provide a larger area that may, for example, be used to display a more detailed system mimic than can be shown on the smaller VDUs of the various stations 32, 34, 36, 60. The vertical panels 64 are arranged in an arc that is viewable (at least in part) from any of the various stations 32, 34, 36, 60. Preferably, the vertical panels 64 provide monitoring displays, but not control inputs. However, it is contemplated to include some controls (preferably redundant) on the vertical panels 64. As another variant, it is contemplated to integrate the MSPs 54, 56 as part of the vertical panels 64, e.g. at the left and right sides to maintain the mnemonic arrangement. With brief reference to FIG. 4, allocation of control functions amongst the stations 32, 34, 36, 60 and the MSPs 54, 56 are diagrammatically shown. In FIG. 4 the acronyms are as follows: PPL=Plant Protection Layer (i.e., systems of the “Plant Protection” category); PCL=Plant Control Layer (i.e., systems of the “Plant Control” category); CCL=Common Control Layer (i.e., systems of the “Common Control” category); and PML=Plant Management Layer (i.e., supervisory systems of the “Plant Management” category). Although the OATC stations 34, 36 are indicated in FIG. 4 as performing functions of the “Plant Control” category, the OATC stations 34, 36 are also capable of performing functions of the “Plant Protection” category. On the other hand, the MSPs 54, 56 are principally intended to perform functions of the “Plant Protection” category, and only incidentially may also be designed to provide some plant control functionality. The SRO station 32 is indicated as providing HMI for the systems of the “Plant management” category; however, it is to be understood that (1) the “Plant management” category typically includes only monitoring (not control) functions, and (2) the SRO station 32 also can also monitor (but not control) systems under the “Plant protection”, “Plant control”, and “Common control” categories. With reference back to FIG. 3, placing the SRO station 32 inside the control room 30 advantageously enhances the ability of the SRO to monitor and communicate with the OATCs and with the NLO in charge of the systems of the “Common control” category. However, the SRO also has other duties, including management of all aspects of the nuclear power plant, including business aspects unrelated to the technical matters of daily operation of SMR #1 and SMR #2. To accommodate the SRO in performing these tasks, the control room 30 optionally also includes an enclosed office 70 for use by the SRO. The office 70 can be a completely walled office, or can be a cubicle with walls that do not extend to the ceiling (not shown) of the control room 30. The walls of the office 70 are preferably transparent (e.g., glass, plexiglass, et cetera) at least for those walls facing the operator stations 32, 34, 36, 60, so that the SRO can continue to monitor plant operators while performing office tasks. Optionally, the control room 30 further includes a meeting room 72, which can be used by the SRO or others to conduct business meetings. The optional meeting room 72 and/or office 70 also provides a convenient “observation deck” from which visitors to the nuclear power plant can view operation of the control room 30 without impeding the OATCs and NLO in the performance of their duties. With brief reference back to FIG. 1, in illustrating the layout of the control room 30, for convenience SMR #1 is shown on the left of the SRO station 32 and SMR #2 is shown on the right of the SRO station 32. However, the mnemonic reference value of this physical placement of the SMR units is generally not useful since the control room 30 typically does not include windows through which plant operators in the control room 30 can see the physical SMR units. Accordingly, the placement of SMR #1 and SMR #2 as shown in FIG. 1 is not of especial value. Nonetheless, in some embodiments the illustrated placement of SMR #1 and SMR #2 may be followed in the physical plant layout, which may be useful since the plant operators are expected to have the physical layout of the nuclear power plant memorized. With reference to FIG. 5, the data network of the control room 30 is diagrammatically shown, including arrows indicating data flow. In FIG. 5, double-headed arrows indicate unidirectional data flow (i.e. data flow in one direction only). In the illustrative data network of FIG. 5, the Plant Management Layer (corresponding to the SRO station 32 and the supervisory systems of the “Plant Management” category) is monitoring-only, as indicated in FIG. 5 by double-headed arrows feeding into (but not out of) the Plant Management Layer. The Common Control Layer corresponding to the NLO station 60 may be able to monitor activities of the systems of the Plant Control Layer and Plant Protection Layer, but cannot control those systems. The Common Control Layer does have both monitoring and control capability with respect to the plant common systems of the Common Control category. As further seen in FIG. 5, both the Plant Protection Layer #1 and the Plant Control Layer #1 have both monitoring and control capability respective to SMR #1, and similarly both the Plant Protection Layer #2 and the Plant Control Layer #2 have both monitoring and control capability respective to SMR #2. The Plant Control Layer of each SMR unit can monitor the Plant Protection Layer of that SMR unit; however, the converse is not true, i.e. the Plant Protection Layer cannot monitor the Plant Control Layer. This is because the Plant Protection Layer operates in a response mode—i.e., when a particular safety alarm is tripped, the Plant Protection Layer responds by performing a designated safety response. In this operation, the Plant Protection Layer does not need to know the current state of the plant control operation. It will be further noted in FIG. 5 that the OATC station 34 provides a HMI for both Plant Protection Layer #1 and Plant Control Layer #1, whereas the MSP 54 provides HMI only for the Plant Protection Layer #1 (although it is contemplated to provide some Plant Control Layer HMI capability at the HMI). In the same way, the OATC station 36 provides a HMI for both Plant Protection Layer #2 and Plant Control Layer #2, whereas the MSP 56 provides HMI only for the Plant Protection Layer #2. In the illustrative embodiment, the OATC workstations 34, 36 are located in front of and to the side of the Central SRO workstation 32 at a sufficient angle “to the side” to allow the SRO to directly observe the OATCs at the OATC stations 34, 36. In some embodiments the control room 30 is arranged with bilateral symmetry about a vertical symmetry plane passing through both the SRO station 32 and the NLO station 60, with the OATC workstation 34 and MSP 54 for SMR #1 on one side of the symmetry plane (i.e., the left side in the illustrative embodiment), and the OATC workstation 36 and MSP 56 for SMR #2 on the other side of the symmetry plane (i.e., the right side in the illustrative embodiment). This provides a physical delineation of operations between the two SMR units while centrally placing the SRO and NLO so as to be able to monitor and react to events occurring in either or both SMR units. As described, a bilaterally symmetric configuration for the control room 30 is advantageous. However, some asymmetry is contemplated, for example if SMR #1 and SMR #2 are not identical such that there are some differences between the OATC workstations 34, 36 and/or between the MSP's 54, 56. The minimum number of operators for the control room 30 is four—one SRO, two OATCs, and one NLO. Of these, three operators (the SLO and the two OATCs) are licensed, while the NLO can be an unlicensed operator. All of these operators are stationed in the same control room 30 and can therefore communicate face-to-face with each other. Optionally, there may be additional operators, either inside or outside of the control room 30. For example, one or more mobile operators, who typically may be unlicensed operators, may be available to perform mobile tasks such as tagging system components in or out, directly visually confirming status of various components, and so forth. With reference to FIGS. 6 and 7, the disclosed control room embodiments are readily expanded to additional reactor units. In FIG. 6, one approach for expanding the twin-pack configuration of FIGS. 1-5 to a four-pack is illustrated. This approach simply duplicates all systems, so that there are now two control rooms 30, each controlling two SMR units 1. In this case the number of operators requires is doubled—two SROs (one for each control room 30), four OATCs (two in each control room 30), and two NLOs (one for each control room 30). In practice, an additional SRO-level operator may be needed to oversee the two control rooms 30, so that the number of operators is nine (three SROs, four OATCs, and two NLOs) of which seven operators must be licensed operators. FIG. 7 shows an alternative control room 30′ that expands the arrangement of the control room 30 to enable control of all four SMRs 1 from the single control room 30. The expansion includes adding two additional OATC stations and two additional MSPs. However, the control room 30′ is still staffed by only one SRO and only one NLO, so that the total number of operators is six (one SRO, four OATCs, and one NLO). Such expansion is contemplated to be further extended in analogous fashion to five or six reactor units; however, as more reactor units are added the supervisory burden on the SRO increases, so that it is expected that no more than six reactor units can be supervised by a single SRO even using the disclosed control room. The preferred embodiments have been illustrated and described. Obviously, modifications and alterations will occur to others upon reading and understanding the preceding detailed description. It is intended that the invention be construed as including all such modifications and alterations insofar as they come within the scope of the appended claims or the equivalents thereof.
	abstract	A stimulable phosphor sheet for a radiation image recording and reproducing method comprising the steps of recording a radiation image as a latent image, irradiating the latent image with stimulating rays to release stimulated emission, and electrically processing the emission to reproduce the radiation image, is preferably composed of a stimulable phosphor-containing grid partition that contains a stimulable phosphor, a UV or visible light-emitting phosphor, or a reflective material and two-dimensionally divides the phosphor sheet on its plane to give plural small rectangular sections, and stimulable phosphor-incorporated areas which are rectangularly sectioned with the grid partition and which have a reflectance at the wavelength of the stimulating rays which differs from that of the grid partition.
055641024	summary	BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a method of subjecting a high-level radioactive liquid waste to a vitrification treatment by using cold-crucible induction melting. 2. Description of Related Art A high-level radioactive liquid waste generated from a reprocessing plant is subjected at present to a vitrification or glassification treatment. The reasons why glass is used are because (1) glass is capable of uniformly solid-solving or dispersing almost all components of waste, (2) glass has an excellent stability, and (3) an industrial glass manufacturing method can be applied to manufacture the glass to be used. In order to obtain a vitrified body, a glass melting furnace of a directly supplied current type has heretofore been used. Concretely speaking, a mixture of a high-level radioactive liquid waste and a raw glass material is charged into the melting furnace, and the glass is melted by applying heat thereto by using a preheater. When an electric current is supplied between electrodes disposed in the melting furnace, it flows into the molten glass, which is thereby heated to keep all of the materials charged into the furnace melted. In the conventional melting technique, glass, an object material to be melted contacts directly a structural material (refractory furnace wall and crucible wall) of a melting apparatus under the object material melting temperature conditions. Therefore, the conventional technique poses important problems including the measures for preventing the high-temperature corrosion of the structural materials (i.e. provision of a margin for corrosion or replacement of the structural materials) and limitation on a melting temperature (i.e. setting the highest temperature, at which the strength of the structural materials can be secured, as an upper limit). SUMMARY OF THE INVENTION An object of the present invention is to provide a glass melting treatment method capable of simultaneously solving the problem of the high-temperature corrosion of the structural materials of a melting apparatus and the problem of the limitation of a melting operation temperature set on the basis of the heat resisting temperature of the structural materials of the melting apparatus. To solve these problems, the present invention utilizes a cold crucible induction melting method. When a material to be melted is a metal in the cold-crucible induction melting method, a floating force working on the material occurs due to an operation of an electromagnetic field, so that the material can be melted without causing the same to contact a melting furnace body. Therefore, the characteristics of this method reside in its capability of minimizing the corrosion of the furnace body with the molten material in addition to its capability of melting a material having a high melting point. Accordingly, this method is utilized for melting special metals in the iron and steel industries at present. However, when the cold-crucible induction melting method is used, an object material to be melted necessarily has a conductivity, and this method cannot be utilized as it is for melting glass. The glass melting treatment method according to the present invention comprises the steps of charging a radioactive liquid waste and a glass material into the interior of a melting furnace in a cold-crucible induction melting apparatus, inserting a conductor the melting point of which is higher than that of the glass material into the interior of the melting furnace, supplying a high-frequency current to a high-frequency coil in the melting apparatus so as to generate heat in the conductor and indirectly heat the glass material with the generated heat, withdrawing the conductor after a part of the glass material has been put in a molten state, and thereafter keeping the glass material as a whole in a molten state while maintaining the induction heating by the molten glass material. The conductor inserted into the melting furnace is, for example, a silicon carbide rod. A mixture of a radioactive liquid waste and a glass material does not have a conductivity. Therefore, even when a high-frequency current is supplied to the high-frequency coil after this mixture has been inserted into the melting furnace in the cold-crucible induction melting apparatus, heat is not generated in the mixture. However, when a conductor having a high melting point, such as a silicon carbide is present, the electric current flows therethrough, and the conductor is induction heated. Owing to the heat thus generated, the surrounding glass material is heated indirectly and put in a partially molten state in a short time. When the glass material is put in a molten state, it becomes conductive. Consequently, an electric current flows through the molten glass material in response to the high-frequency current flowing in the high-frequency coil, and the glass material is induction heated. Now that the glass material has begun to be induction heated, the conductor such as silicon carbide becomes unnecessary, and the molten glass material is heated directly. The molten region increases gradually, and the whole of the material is melted shortly. When an object material to be melted is such a glass material, the surface thereof which contacts the inner surface of the melting furnace is cooled to become a solid layer (skull), so that the molten material does not directly contact the refractories, whereby the high-temperature corrosion of the melting furnace can be prevented. Since the melting furnace is cooled with water, the heat resisting temperature thereof does not restrict a melting operation.
	description	This application claims the benefit of U.S. Provisional Patent Application No. 62/715,398, filed Aug. 7, 2018 and U.S. Provisional Patent Application No. 62/865,486, filed Jun. 24, 2019, each of which is hereby incorporated by reference herein in its entirety. This invention was made with government support under DE-SC0017855 awarded by Department of Energy. The government has certain rights in the invention The present disclosure relates to coating systems and more particularly pertains to new systems and methods for application of stress corrosion cracking resistant cold spray coatings for mitigation and repair of compromised regions of a container. There is a critical need for a minimally invasive mitigation and repair technology to mitigate environmental, corrosion, shipping, and accidental damage to hazardous waste storage canisters, especially those located in areas inaccessible by traditional repair means. These hazardous waste storage canisters can include, for example, hazardous chemical storage containers, vitrified radioactive waste storage containers, Greater Than Class C (GTCC) nuclear waste storage canisters, horizontal spent fuel canisters, vertical spent fuel canisters, Dry Cask Storage Systems (DCSS), nuclear fuel transportation canisters, and other canisters storing hazardous and radioactive waste. For the purpose of this disclosure, these canisters and containers are collectively referred to as Hazardous Waste Containers (HWC). Typically, although not necessarily, when an HWC is positioned at a storage facility and loaded with waste, the HWC is positioned within an overpack container which is somewhat larger than the HWC so that a relatively thin annular gap is formed between the outer surface of the perimeter wall of the HWC and an inner surface of the overpack container which defines a chamber of the overpack container. The overpack container may include vent openings at upper and lower locations to allow air circulation into the annular gap. Mitigation and repair of these HWC is especially critical for long term storage applications, where canister materials are exposed to the environment. Material degradation of canisters may occur during the extended storage period. One of the primary degradation modes of interest for welded canister designs is chloride-induced stress corrosion cracking (CISCC) of the canister due to sensitization of the stainless-steel material and tensile residual stress from the welding process used to form or close the canister. Other degradation mechanisms can include galvanic corrosion, pitting, or damage from transportation, loading, or natural disaster. Developments in the long-term maintenance and repair of DCSSs are rather limited, as these systems have only been licensed for approximately the last 20 years and were not designed for long term storage. With the uncertainty facing long term, geologic storage facilities, long duration on-site waste storage is being now considered, and therefore only recently have long term degradation effects and mitigation and repair methods for these systems been considered. Weld overlay cladding is one approach often used for corrosion control and substrate isolation as a corrosion and CISCC repair and mitigation strategy. However, welding leaves the material with degraded corrosion properties in the heat affected zone of the weld and introduces tensile residual surfaces stresses. The degraded corrosion properties can lead to pitting and CISCC initiation in those areas, and the tensile residual stresses can cause crack opening and propagation through the material. Shot peening and laser shock peening are other approaches often used to introduce a layer of compressive residual surface stresses to eliminate CISCC concerns. However, these processes do not apply an isolation layer with superior corrosion resistance, so the material is still susceptible to pitting and corrosion, and eventually CISCC. From the existing prior art in the DCSS industry, one notable example is found in U.S. Patent Application Publication No. 2013/0340225A1 entitled “SYSTEMS AND METHODS FOR CANISTER INSPECTION, PREPARATION, AND MAINTENANCE”. This publication discusses a travel system for canister preparation, inspection and/or repair for both horizontal and vertical canister systems. The publication discusses inspection of the canisters using eddy current, dye penetrant, ultrasonic sensors, laser ultrasonic sensors, and/or visual sensors. The publication also discusses maintenance and repair of the canisters using dry ice blasting, repairing cracked welds, and applying protective coatings. However, the usage of cold spray is not discussed and the techniques discussed require the operator to remove the canister from the overpack container and transfer it through the sensing and repair ring which is attached to the overpack container, and therefore the techniques discussed in this publication may not be performed with the canister in-situ in the overpack container. While patent and patent application publication documents relating to aspects of cold spray technology for certain applications are known, the applicants are unaware of any documents that discuss the use of cold spray techniques capable of use within a DCSS for CISCC mitigation and repair in-situ in the overpack container. For example, U.S. Patent Application Publication No. 2009/0011123A1 entitled “CORROSION PROTECTIVE COATING THROUGH COLD SPRAY” which discusses a cold spray coating process for applying a corrosion resistant coating in the specific context of turbine component repair. The document discusses the use of a corrosion resistant coating in which the coating material possesses superior corrosion resistance as compared to the parent material, but specifies the use of aluminum, magnesium, and silicon as the cold spray material. Additionally, nothing is disclosed about the application of compressive residual stress in the coating material. Another example, U.S. Patent Application Publication No. 2006/0090593A1 entitled “COLD SPRAY FORMATION OF THIN METAL COATINGS” discusses a cold spray process for applying thin layers of metallic material of about 1 micron in thickness, which is thinner than what is believed effective for the applications addressed by the present disclosure. The techniques discussed in this publication also employ large, hard spheres which would, if ever applied to a HWC, undesirably result in significant ablation of the HWC surface and generation of large amounts of debris within the overpack container. Further, U.S. Patent Application Publication No. 2007/0181714A1 discusses a cold spray nozzle for coating small diameter bores, however the apparatus is specifically intended not to adhere the powder to the surface making it unacceptable for the purpose of repairing a HWC. Therefore, a safe method of mitigation and repair of CISCC in HWCs is desired that may not introduce thermal effects, that may introduce compressive residual stresses, that may apply a CISCC resistant isolation coating, and that may be done both prior to the container entering service (e.g., pre-service mitigation), while the container is in-service, and while the container is in-situ (e.g., for mitigation and repair). In one aspect, the present disclosure relates to a method of forming a partial coating on a canister having a perimeter wall with a surface. The method may comprise identifying a compromised region on the surface of the wall of the canister, and impacting a substantially linear flow of particles of a powder against an area in the compromised region of the surface in a manner effective to cause the particles of the powder to bond to the surface of the wall to produce a coating on the area of the compromised region. The method may further comprise moving the substantially linear flow in a direction substantially parallel to the surface of the wall to cause the particles of the powder to impact an additional area of the compromised region of the surface to cause the particles of the powder to bond to the surface of the additional area of the compromised region. Aspects of the present disclosure utilize cold spray application of material to the surface of an HWC which may have a number of advantages over conventional approaches to HWC repair. For example, as compared to the use of a weld overlay on the surface of the HWC, cold spray techniques can deposit a coating with superior corrosion performance with no heat affected zone with compressive residual surface stresses. Therefore, the material is less susceptible to pitting and CISCC initiation and the compressive residual stresses act to close crack tips and stop crack propagation. As compared to shot peening of the HWC surface, cold spray techniques also apply compressive residual stress layer in the base material and the deposited isolation coating through very high velocity particle impact and bonding. Therefore, not only does cold spray apply crack closing compressive residual stresses, it further isolates the surface from corrosion attack with a corrosion resistant material. There has thus been outlined, rather broadly, some of the more important elements of the disclosure in order that the detailed description thereof that follows may be better understood, and in order that the present contribution to the art may be better appreciated. There are additional elements of the disclosure that will be described hereinafter and which will form the subject matter of the claims appended hereto. In this respect, before explaining at least one embodiment or implementation in greater detail, it is to be understood that the scope of the disclosure is not limited in its application to the details of construction and to the arrangements of the components, and the particulars of the steps, set forth in the following description or illustrated in the drawings. The disclosure is capable of other embodiments and implementations and is thus capable of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present disclosure. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present disclosure. The advantages of the various embodiments of the present disclosure, along with the various features of novelty that characterize the disclosure, are disclosed in the following descriptive matter and accompanying drawings. With reference now to the drawings, and in particular to FIGS. 1 through 8 thereof, new systems and methods for application of stress corrosion cracking resistant cold spray coatings embodying the principles and concepts of the disclosed subject matter will be described. Aspects of the present disclosure may provide several advantages that produce a superior solution for mitigation and repair of chloride-induced stress corrosion cracking (CISCC), specifically within regions of sensitized and high tensile residual stress, otherwise known as heat affected zones (HAZ) of welded hazardous waste containers (HWCs). In accordance with one aspect of the disclosure, a high-pressure cold spray system may be provided to apply a coherent, dense cold spray coating on the container surface of the HWC. In a preferred embodiment, a high-pressure cold spray system such as is described in U.S. Patent Application Publication No. 2014/0117109 entitled “COLD SPRAY DEVICE AND SYSTEM” (which is hereby incorporated by reference in its entirety), is provided to apply the cold spray coating. In some implementations the cold spray applicator of the system may be manipulated by hand and in some implementations the cold spray applicator may be moved robotically over the container surface during the cold spray application. In accordance with at least one embodiment of the present disclosure, a coating may be applied to the container surface of the HWC using high pressure cold spray. In embodiments of the disclosure, the coating may comprise metals of various types including 304(L), 316(L), 904(L), 410, Duplex Stainless Steel, Inconel 600, Inconel 625, Inconel 718, Nickel, C-276, K-500, or Ni—Cr—Mo alloy, or a metal matrix composite (MMC) with metal matrix matching the composition of those materials listed. In embodiments, the coating may comprise a Ni—Cr—Mo alloy or a metal matrix composite with a metal matrix consisting of a Ni—Cr—Mo alloy. In further embodiments, the coating may comprise a Ni—Cr—Mo pure ternary alloy having approximately 59 percent to approximately 64 percent Ni, approximately 20 percent to approximately 23 percent Cr, and approximately 16 percent to approximately 18 percent Mo. Embodiments of the disclosure may include the introduction of compressive residual stresses provided by the high-pressure cold spray coating throughout the coating and into the container surface of the HWC for mitigating development of cracking and improving the corrosion resistance in a manner similar to shot peening. In embodiments, the cold spray coating may be applied over the weld HAZ of the assembled HWC. The HWC, typically comprising steel, stainless steel, and/or nickel alloy, in the austenitic condition is susceptible to CISCC within the sensitized and high tensile residual stress weld HAZ. The cold spray coating applies compressive residual stress to the weld HAZ and may isolate the HAZ from the corrosive atmosphere. In implementations of the present disclosure, cold spray mitigation coatings may be applied pre-service (e.g., before the HWC is loaded with hazardous material) over weld HAZs. In other implementations, cold spray repair and/or mitigation coatings may be applied in the field (e.g., remote from the point of HWC fabrication) such as at or close to the location of the ultimate usage of the HWC for storage. In further implementations, cold spray repair and/or mitigation coatings may be applied using canister manipulation tooling, such as, inspection rings, such as is described in U.S. Patent Application Publication No. 2013/0340225 A1. In implementations, cold spray repair and/or mitigation coatings may be applied in-situ. Generally, in-situ application of cold spray repair and/or mitigation coatings may be defined as the application of cold spray to the container surface of the HWC without moving, hoisting, transferring, rotating, or otherwise disturbing the HWC. In the case of HWCs being used for spent nuclear fuel storage, in-situ repair and/or mitigation may be performed within the concrete overpack such that removal of the HWC from the overpack is not performed. In some implementations, cold spray repair and/or mitigation coatings are applied in-situ from inspection robots such as robots similar to those discussed in U.S. Pat. No. 10,315,715 entitled “MOBILE, CLIMBING ENDLESS TRACK ROBOTIC SYSTEM TO PERFORM REMOTE INSPECTIONS ON STRUCTURES” and U.S. Patent Application Publication No. 2018/0154960 entitled “CLIMBING VEHICLE USING SUCTION WITH VARIABLE ADAPTIVE SUSPENSION SEAL”, both of which are hereby incorporated by reference in their entireties. Cold spray systems useful for the practice of aspects of this disclosure are commercially available, including, for example the VRC Gen III Hybrid Portable High Pressure Cold Spray System available from VRC Metal Systems, 525 University Loop, Suite 211, Rapid City, S. Dak. 57701 USA., although other systems may be suitably adapted or configured for use according to the present disclosure. For applications with restricted access, for instance in-situ mitigation and repair conducted within the overpack of a DCSS system, a high-pressure cold spray system with remote powder injection is typically required. For the practice of the present invention, the COLD SPRAY DEVICE AND SYSTEM, disclosed in U.S. Patent Application Publication No. 2014/0117109A1 discloses an apparatus that may be useful to remotely apply the cold spray coating according to the present disclosure. The cold sprayed metal coating of the present disclosure may be created from powdered metal feedstock. The particles of the metal powder feedstock may have a plurality of sizes and shapes. Sizes as small as approximately 5 μm in diameter and large as approximately 100 μm in diameter can successfully be deposited using high pressure cold spray. Preferably, the powders are roughly approximately 18 μm to approximately 45 μm in diameter. Particles smaller than approximately 5 μm carry less momentum and may not be effectively carried through the substrate bow shock. Powders having particle sizes less than 5 μm may also pose safety and environmental concerns due to the ability of the particles to remain suspended in air for long periods of time. Therefore, powder particles smaller than approximately 18 μm may be excluded from the particles used for cold spraying using any suitable technique, such as, for example, using ultrasonic vibratory sieving, fluidized bed separation, or other particle size classification method. Particles larger than approximately 45 μm may also be similarly removed from the particles to be sprayed, due at least in part to their higher mass and inability to achieve critical velocity and be effectively deposited on the container surface. This powder classification may enhance high particle deposition efficiency, low porosity of the resulting coating, and high-quality characteristics of the coating. Powder morphology is also important in the cold spray process. The highest quality powders may be made using gas atomization techniques and may be highly spherical in shape, and thus may provide the best results for the techniques in this disclosure. Suitable materials for the metal powders of the present disclosure may be composed of pure powders and blends containing the pure metal powders as a metal matrix, including, for example, titanium, chromium, cobalt, nickel, copper, zinc, niobium, molybdenum, silver, and tantalum. The most highly suitable materials making up the metal powders of the present disclosure may be selected from the group of highly corrosion resistant Fe, Ni, and/or Cr containing alloy materials including: 304/304L stainless steel, 316/316L/316Ti stainless steel, 904L stainless steel, 321 stainless steel, 410 stainless steel, and 2205 duplex stainless steel. Other highly suitable highly corrosion resistant Ni-, Cr-, and/or Mo-containing alloy materials may include: Alloy C-276, Alloy K-400, Alloy K-500, Alloy 22, Alloy 59, Alloy 600, Alloy 625, Alloy 718, or other Ni—Cr—Mo alloy. In some preferred embodiments of the present invention, the Ni—Cr—Mo pure ternary alloy having approximately 59 percent to—approximately 64 percent Ni, approximately 20 percent to approximately 23 percent Cr, and approximately 16 percent to approximately 18 percent Mo, hereafter referred to as Alloy 59, may be utilized in the practice of the disclosure. Metal powders useful in the implementations of the disclosure are typically commercially available. For example, Praxair Surface Technologies, 1500 Polco Street, Indianapolis, Ind. 46222, offers a wide variety of pure materials and alloys in classified spherical powders useful for the present invention, including Pure Nickel (NI-914-3), Alloy 718 (NI-202-2), and Alloy 625 (NI-328-5/1265F). Several other sources and other types of spherical and irregular metal powders are known to those skilled in the art and may be useful in practicing the invention. For nuclear waste applications, it is desired that the metal, metal alloy, or metal blend forming the powder does not contain materials that are capable of forming long lived radioactive isotopes when exposed to neutron flux or other forms of radiation, such as cobalt. A preferred material for the particles used for the cold spray of the present disclosure excludes cobalt. Useful for application of the present disclosure in nuclear waste storage are those materials that have a relatively high neutron absorption cross-section, such as materials containing boron, gadolinium, and hafnium. Highly suitable are alloys of the materials for the particles listed above that are augmented to contain materials with a high neutron absorption cross section, such as, for example, the 316NU metal alloy powder commercially available from Carpenter Technology Corporation, 1735 Market Street, 15th Floor, Philadelphia, Pa. 19103 USA. Materials making up the metal powders of the present invention may also be composed of powders blended from the materials listed previously with other metallic or ceramic particles. Those skilled in the art will recognize that innumerable metal powder blends could be applied in the present invention. Notwithstanding, metal matrix composites provide particular utility to implementation of the present disclosure, where a metal powder is blended with a ceramic or ceramic-containing powder. Metal powders making up the metal matrix may be selected from the group of highly corrosion resistant Fe-, Ni-, and/or Cr-containing materials, and Ni-, Cr-, and/or Mo-containing materials, as listed in this disclosure. Some of the most suitable materials for the metal matrix for CISCC resistant cold spray coating of the disclosure are those materials selected from the Ni—Cr—Mo alloys, including Alloy C-276, Alloy 625, and Alloy 59. Ceramic materials making up the hard phase of the metal matrix composite may be selected from the metallic carbides, including: chromium carbide, tungsten carbide, titanium carbide, molybdenum carbide, hafnium carbide, niobium carbide, tantalum carbide, tantalum niobium carbide, zirconium carbide, vanadium carbide, boron carbide, lanthanum carbide, manganese carbide, silicon carbide, tungsten tantalum carbide, tungsten titanium carbide, tungsten titanium tantalum carbide, and metallic oxides, including: aluminum oxide, aluminum titanate, chromium oxide, yttrium oxide, zirconium oxide, titanium dioxide, silicon dioxide, magnesium oxide, bismuth oxide, cesium oxide, cobalt oxide, copper oxide, iron oxide, gallium oxide, hafnium oxide, niobium oxide, tantalum oxide, tin oxide, zinc oxide, and manganese oxide. The most suitable material for the ceramic metal matrix composite hard phase may include the metal carbides of chromium, tungsten, niobium, tantalum, and hafnium, and metal oxides of zirconium and aluminum. Useful for application of the present in nuclear waste storage are those ceramic blend materials making up the hard phase of the metal matrix composite that have high neutron absorption cross-section, such as boron carbide, boron nitride, gadolinium oxide, and hafnium carbide. These hard phase ceramic additions to the cold spray material can be added, blended, milled, or otherwise included in the aforementioned metal matrix materials for cold spray usage in the practice of the disclosure. A depiction of basic elements of a high-pressure cold spray apparatus 10 is shown in FIG. 1. A gas at high pressure (e.g., approximately 300 psi to approximately 3000 psi) may be fed to a gas control element 12, where the gas flow 14 may be split into the a process gas flow 16 and a carrier gas flow 18. The process gas flow 16 is transferred to a high pressure (e.g., approximately 300 psi to approximately 1000 psi) heating element 20, where the gas is heated for delivery to the applicator nozzle 22. The carrier gas flow 16 may be transferred to a powder feeding module 24, where the particles of the powder are injected into the gas stream. The powder-containing gas stream 26 of the carrier gas flow 18 may be transferred to a mixing device 28 where the powder-containing carrier gas flow is mixed with the heated process gas flow 16 and injected into the nozzle 22. The applicator nozzle may be of the de Laval type, and may accelerate the combined gas flows to supersonic velocity, thereby accelerating the powder towards the nozzle exit 30. The high velocity powder is then directed toward the substrate 32, such as the substrate surface 34 upon which the powder is to be deposited, and upon impact, the powder is bonded to the substrate and/or previously deposited particles into a layer 36 of particles. The nozzle 22 may be moved or traversed, either by hand or robotically, generally parallel to the surface of the substrate such that the location at which the powder particles impact the surface 34 moves across the substrate to create a dense, uniform, and coherent coating on the substrate. An illustrative example of a cold spray coating exhibiting greater than 99% density is shown in FIG. 2. A cold spray application process may produce a high density, high hardness and cold worked microstructure with compressive residual stresses as opposed to the tensile residual stresses associated with fusion welding processes. During the cold spray application process, the metal powder particles typically do not reach melting temperatures, but are fused through kinetic energy transfer and adiabatic shearing processes, therefore substrate heating may be minimized, dimensional stability may be maintained, and unwanted thermal effects may be avoided such as the formation of a heat affected zone (HAZ), creation of thermal stresses, etc. Further, the cold spray application technique may provide the unique ability to adjust or “tune” the composition of the coating applied to meet the corrosion requirements of the components, through an understanding of the corrosion potentials of the substrate and coating. A cross-sectional depiction of a perimeter wall 38 of a HWC and a typical seam weld 40 used on HWCs is shown in FIG. 3, as well as the heat affected zones (HAZ) 42 of the wall 38 located adjacent to the weld 40 itself. Modeling and residual stress measurements both demonstrate that the welding process induces tensile residual stresses in the welded joints sufficient to initiate a stress corrosion crack (SCC). A SCC may be caused by several mechanisms, usually involving a susceptible material, a corrosive environment, and an applied or residual tensile stress. Austenitic stainless-steel alloys, such as ANSI 304/308, are often the primary materials used in HWCs, such as the large existing population of DCSS. These alloys have extreme corrosion and cracking resistance but are susceptible to SCC, especially after extended service life, exposure to temperatures above 60° C. and in the presence of chlorine containing environments (e.g., CISCC), such as those detected at the Diablo Canyon nuclear power plant and associated storage facility. Surface treatments are a key factor in the CISCC susceptibility of these alloys, and dry grinding results in less SCC resistance, and grit blasting or shot peening can increase the SCC which is likely a consequence of the surface stress state (e.g., tensile stress in the case of grinding vs. compressive stress in the case of blasting or peening). Thus, in at least some installations, an HWC may be made from a susceptible material, placed in a chlorine-containing environment, and have a tensile surface stress sufficient to initiate a crack. Implementation of aspects of the present disclosure may provide the application of a dense, corrosion resistant, isolation coating with compressive residual stresses directly over the weld and HAZ, thereby mitigating and repairing damage, CISCC, corrosion or otherwise. In one highly suitable implementation of the present disclosure, a cold spray coating with thickness of approximately 0.015 inches (approximately 0.4 mm) to approximately 0.075 inches (approximately 2 mm) is applied over at least one weld, and in some cases every weld, present on the HWC, across an area of the container surface having a width of approximately 3 inches (approximately 76 mm) to approximately 6 inches (approximately 152 mm), with the area being substantially centered on the defect. In one implementation of aspects of the disclosure, such as is illustratively depicted in FIG. 4, a cold sprayed CISCC mitigation coating may be applied to an HWC 50 prior to hazardous material being loaded into the HWC, which will be referred to in this description as “pre-service application”. In embodiments, the HWC may be manipulated by commercially available manipulation equipment 52 while the cold spray mitigation coatings are applied to areas along and about the welds of the HWC, such as circumferential welded areas 54, longitudinal welded areas 56, and base welds 58. A commercially available robotic system 60 can be utilized to manipulate the cold spray applicator 62 to apply uniform and consistent coatings to the welded regions as discussed above. The cold spray process gas may be transferred to the cold spray applicator 62 using a high pressure, high temperature, flexible hose 64, and the powder and carrier gas flow 18 (e.g., powder-containing gas stream 26) may be separately transferred to the cold spray applicator using a high pressure flexible hose, and mixed by a mixing device 28 at or close to the cold spray applicator 62. In other embodiments, the cold spray process gas flow 16, the carrier gas flow 18, and powder may be transferred to the cold spray applicator 62 using a single high pressure, high temperature, flexible hose. One highly suitable and commercially available cold spray system 66 for depositing the cold spray material is sold under the tradename “RAPTOR” by VRC Metal Systems. Other ancillary equipment such as dust collection, engineering controls, and robot controllers 68 may be mounted on a portable trailer system 70 for providing enhanced mobility for the system. Through the practice of the implementations of the present disclosure, corrosion resistant cold sprayed material, such as Alloy 59, with compressive residual stresses can be applied as a pre-service mitigation strategy to potentially eliminate corrosion and CISCC concerns for the HWC processed according to aspects of the disclosure. In one highly suitable implementation, the cold spray pre-service application is performed on welded 304 or 316 stainless steel nuclear waste containers. Advantageously, usage of aspects of the present disclosure has the potential to decrease inspection and sustainment costs of HWC-based storage and improve the public opinion of long-term storage of spent nuclear fuel. In another aspect of the present disclosure, cold spray repair and mitigation coatings can be applied to in-service HWCs, in particular, dry cask storage systems (DCSS) currently holding and storing hazardous material. An illustrative embodiment of the present disclosure, such as shown in FIG. 5, contemplates the application of cold spray repair and/or mitigation coatings may be applied to surfaces of loaded DCSS using canister manipulation equipment known to those skilled in the art. For example, aspects of the present disclosure may be practiced utilizing toroidal-shaped inspection devices, hereafter referred to as inspection rings 78, such as is disclosed in U.S. Patent Application Publication No. 2013/0340225A1 entitled “SYSTEMS AND METHODS FOR CANISTER INSPECTION, PREPARATION, AND MAINTENANCE”. Although other inspection ring designs may be developed by others in the industry, one skilled in the art will recognize that aspects of the present disclosure may be practiced using other inspection ring designs. In the described embodiment, cold spray mitigation and/or repair coatings may be applied to a HWC loaded with nuclear fuel and currently in-service, hereafter referred to as in-service repair and/or mitigation processing. Aspects of the disclosed in-service processing typically require the HWC to be disturbed or manipulated, which is different from “in situ” repair and/or mitigation in which disturbance or manipulation is not required, and may be an important distinction between the respective processing. In an implementation illustratively depicted in FIG. 5, a horizontal DCSS system, with a nuclear waste storage HWC 80 being removed from a horizontally-oriented cavity of a concrete overpack 82. Using techniques and apparatus such as is disclosed in U.S. Patent Application Publication No. 2013/0340225A1, one skilled in the art will recognize that aspects of the present disclosure may also be practiced using inspection ring devices designed for DCSS having a vertically-oriented cavity in the concrete overpack. The cold spray applicator 86 may be fixed to the rotary tool holder 84 and manipulated to move into a position over or adjacent to the site to be repaired and/or mitigated, such as a longitudinal weld seam 56. The cold spray applicator may be connected to a cold spray system 88 using a flexible, high pressure, high temperature hose 90. In one embodiment of the present invention, cold spray process gas is transferred to the cold spray applicator using a high pressure, high temperature, flexible hose. Optionally, powder and carrier gas may be separately transferred to the cold spray applicator using a high pressure flexible hose, and mixed at the cold spray applicator. In another embodiment, cold spray process gas, carrier gas, and powder is transferred to the cold spray applicator using a single high pressure, high temperature, flexible hose. For the repair of cracks or pits in which the cold spray coating does not entirely fill the pit or crack, a technique of repair may be an embedded flaw repair in which the flaw may be completely encased by the cold spray coating, which may be effective in mitigating further damage at the damage site. Embedded flaw repair has been reviewed by the Nuclear Regulatory Commission (NRC), and has received a Safety Evaluation Report (SER) to allow its use for repairs in such situations. Through the practice of aspects of the present disclosure, cold spray repair and mitigation coatings can be applied to in-service HWCs, in particular DCSS, without hoisting, manipulating, or otherwise disturbing the nuclear waste HWC, referred to herein as in-situ repair. An illustrative embodiment of the present disclosure, such as shown in FIG. 6A, contemplates the application of cold spray repair and mitigation coatings applied while the HWC is positioned in the DCSS overpack using inspection robots such as those disclosed in U.S. Pat. No. 10,315,715 and U.S. Patent Application Publication No. 2018/0154960. Although other inspection and repair robots may be developed by others in the industry, one skilled in the art will recognize that aspects of the present disclosure may be practiced using remotely controlled robot designs. An illustrative cold spray robotic repair and/or mitigation may include elements delivered to a vertically-oriented DCSS through a concrete overpack 100 via the upper vent access 102 by means of robotic crawler 104. While the robotic cold spray apparatus depicted in FIG. 6A is shown in the context of a vertically-oriented DCSS in a vertically oriented chamber in the overpack, one skilled in the art will recognize that aspects of the present disclosure may also be practiced using remote control robotic platforms designed for horizontally-oriented DCSS situated in a vertically oriented overpack chamber. Illustratively, a flexible high-pressure stainless-steel hose 106 may be pulled by the robotic crawler into the DCSS. Once the crawler has navigated the vent access, the container surface 108 can be inspected and cold spray repair and/or mitigation can be performed within the overpack-to-container annular gap 110. The cold spray repair robotic crawler 104 may deliver a miniaturized cold spray apparatus 112. U.S. Patent Application Publication No. 2014/0117109 discloses a highly suitable cold spray apparatus for the practice of the embodiment of the present disclosure. An illustrative cold spray apparatus 112 is depicted in FIG. 6B. to accomplish in-situ application of cold spray mitigation and repair coatings within the overpack. in some highly suitable implementations of the present disclosure, high pressure gas may be injected into the powder feeder module 114 from the cold spray equipment at the powder feeder gas inlet 116, where powder is fed into the gas, and the powder-gas mixture is injected to the heater module 118 via the powder injection hose 120. High pressure gas is injected into the heater module 118 at the heater injection point 124, where the gas is heated and mixed with the powder-gas mixture. This blend is then injected into a flexible high-pressure gas hose 126, which carries the mixture into the DCSS to the cold spray applicator device 128 attached to the spray robot 130. FIG. 6 depicts an illustrative embodiment of a cold spray applicator apparatus. At the applicator, the hot gas powder mixture is injected at the injection point 132, such as is shown in FIG. 6C, where it travels to the applicator body 134 and into the supersonic nozzle 136. The applicator device is attached to the spray robot via heat shield 138 and heat-resistant chassis 140. The crawler may navigate the container surface of the HWC via magnetic wheels 142 or using suction or some other mechanism. Significantly, the size and shape of the applicator apparatus may be configured to navigate not only the relatively narrow space of the annular gap between the container surface of the HWC and the overpack container, but also to move through the vent opening in the overpack and then from the vent opening into the annular gap, and these spaces may be oriented substantially perpendicular to each other. In general, the technology utilized to move the robotic vehicle on the container surface should be sufficient to support the weight of the vehicle on the container surface of the HWC and withstand the reaction forces applied to the vehicle by the pressure of the cold spray material flow in a manner that also permits substantially free movement of the vehicle across the surface. Additionally, the vehicle be suitably be able to pull high pressure hose through the vent of the overpack container. As an example, the robotic vehicle may utilize magnetic wheels which exert a magnetic attachment or attraction force with respect to the perimeter wall of the HWC. As a further example, pneumatic wheels may also be utilized on the crawler with sufficient vacuum attachment force to the container surface. Additionally, while a magnetic wheeled remote-controlled robot is disclosed, a plurality of remote control robots are available that use other technologies and structures to accomplish a temporary attachment or connection to the HWC using, for example, vacuum, suction, spring force, and adhesives to provide traction. Examples of robotic vehicles suitable for adaptation for use with cold spray applicator apparatus are available from Robotic Technologies of Tennessee, 1615 Brown Ave. Suite 1, Cookeville, Tenn. 38501. Further, elements of the robotic vehicle may be suitably resistant to the heat generated and transmitted to the environment and surrounding structures by the cold spray application process, and in particular the heat of the gases utilized. Shielding may be provided on the vehicle to shield heat sensitive elements of the vehicle from the heat generated by the cold spray application process. In some implementations, the cold spray nozzle may have at least one degree of freedom of adjustment for adjusting the point of impact of the flow of powder particles. Those skilled in the art will recognize that aspects of the present disclosure may be practiced using other applicator device designs suitable for supporting a supersonic nozzle, including those which are commercially available tube fittings, custom machined designs, and/or 3D printed designs. In these implementations, it may be advantageous to utilize “de-tuned” or sub-optimal processing conditions specifically designed to not allow the powder particles to reach critical velocity, thereby prohibiting bonding of the particles to the surface. This technique allows surface preparation of the HWC prior to cold spray coating. This surface preparation technique may remove oxidation, debris, corrosion, and other contamination from the surface. This may also provide an ideal surface cleanliness and roughness to accept cold spray coating. This may improve bonding of the coating to the substrate and eliminate corrosion concerns at the interface from entrapped corrosive species. Using the cold spray process, it is possible to deposit many different types of metals and alloys. Aspects of the present disclosure were developed through iterative process improvement of several cold spray materials. The table of FIG. 7D lists several of the materials investigated in this process, including 304L stainless steel, 316L stainless steel, 904L stainless steel, Inconel 625, and Alloy 59. To determine the efficacy of cold spray materials for CISCC prevention, the materials listed in the table of FIG. 7D were cold sprayed on small-scale V-notch welded specimens, comprised of 304L material, ¼″ thick, welded with a single pass wire feed process using 308 weld wire. Cold spray coatings of 304L, 316L, 904L, Inconel 625, and Alloy 59 were deposited over the weld and HAZ on a single side of the welded coupon to a thickness of 0.010 to 0.025 inches using previously developed processing conditions with a VRC Metal Systems Gen III high pressure cold spray system. Samples were sprayed with helium or nitrogen processing gas according to their cold-spray ability as previously developed. The samples were tested using ASTM G36 boiling MgCl testing to generate stress corrosion cracks. This testing is reported to be extremely severe, causing cracking very quickly in crack resistant 304 and 316 stainless steel materials. The testing was conducted using 32% wt. MgCl in deionized H2O, boiling at 120° C. The samples were subjected to ASTM G36 testing for a total of 24 hours. It was found that the weld residual stresses present in the control sample were sufficient to cause significant pitting, surface cracking, and through-thickness cracks. Cracking was also present in the cold sprayed samples, however in every material, cracking did not originate on the cold sprayed surface. Therefore, the cold sprayed materials are classified as Crack Resistant in the table given in FIG. 7D. Additionally, in all cold sprayed samples, cracking developed on the backside (non-cold sprayed side) of the sample and propagated through the sample thickness. In some cold spray material cases, the propagating crack continued through the cold spray interface and through the coating, as shown in FIGS. 7A and 7B. However, in some cold spray material cases, i.e., 316L, and Inconel 625, the propagating crack was arrested below the cold spray interface, as shown in FIG. 7C. This is a consequence of the compressive residual stresses imparted to the substrate during the cold spray process. These materials were classified as Crack Arresting in the table in FIG. 7D. The other two significant factors that were used in the down-selection of the materials described in the embodiments of the present disclosure were the galvanic potential and the pitting resistance of the materials. Galvanic potentials and pitting potentials for each of the cold sprayed materials were determined using ASTM G61 Cyclic polarization testing, and they were compared to those of wrought 304L stainless steel determined using the same procedure. Cold spray materials with electrochemical potential within 100 mV of 304L stainless steel were classified as Galvanically Matched. Cold spray materials with pitting potential greater than that of 304L stainless steel were classified as Pitting Resistant. Results of the down-selection testing is summarized in FIG. 7. This example demonstrates a down-selection process used to reduce the cold spray CISCC invention to practice. The present disclosure comprises a cold spray material that can be applied to a DCSS either pre-service, in-service, and/or in-situ at low temperatures, contains crack-retarding compressive residual stresses, may achieve over 69 MPa adhesive strength with matched galvanic potential and improved pitting potential, making aspects of the disclosure a highly advantageous system for mitigation and repair of CISCC DCSS applications, as well as numerous long term hazardous and nuclear waste storage applications. In a highly advantageous implementation of the present disclosure, the cold spray repair and/or mitigation coating is robotically applied in-situ, which is defined as being applied without moving, manipulating, exposing, or otherwise disturbing the loaded HWC system. In this implementation, the robotic system is used to navigate the vent opening located on the hazardous or nuclear waste storage HWC, e.g. DCSS. Navigation through the vent opening places significant limitations on the size of the apparatus moving through the vent opening, and requires specific miniaturized geometry for embodiments of the disclosure. Illustratively, the robotic crawler must be able to traverse multiple 90° corner features prior to reaching the gap formed between the steel-lined overpack and the HWC to access the stainless-steel HWC itself. The cold spray robot crawler may then navigate in the gap using integrated navigation cameras to the damage site while pulling the flexible cold spray hose. The techniques of the disclosure are particularly advantageous when applied to an HWC which is designed to contain, or contains, fissile nuclear material, nuclear fuel, spent nuclear fuel, nuclear weapons, irradiated waste, greater than class C waste, vitrified waste, or other radioactive substance for the purpose of storage (short or long term) as well as for transportation. An example of a suitable HWC is a Dry Cask Storage System (DCSS) useful for the storage of spent nuclear fuel. Illustrative DCSS may be suitably formed from materials such as SCC susceptible austenitic stainless steels, which include, which include for example ANSI 304/304L, ANSI 316/316L, and ANSI 308. In an illustrative implementation of the disclosure, the HWC may has an outer diameter of approximately 1.75 m, the annular gap between the container surface of the HWC and the inner surface of the overpack container has a width of approximately 76 mm, the vent in the overpack container has a height of approximately 97 mm, and a vertical distance between the vent location and the top of the HWC is approximately 228 mm. Further illustrative implementations of the disclosure utilize a cold spray material deposition system which may operate with a working gas temperature of approximately 700° C. or lower (measured at the cold spray nozzle inlet). The deposition system may also operate at a working gas pressure of approximately 1000 psi or lower (measured at the cold spray nozzle inlet) and may utilize, for example, helium, nitrogen, and/or compressed air as the process and carrier gases. Usage of the techniques of the disclosure may advantageously apply a coating of a corrosion resistant material to the container surface of the HWC that is less susceptible to corrosion damage than the material of the container surface, and imparts or applies to the container surface a compressive residual stress which beneficially discourages cracking in the material Broadly, such cold spray application materials may include powder feedstock from the group of pure metal powders including titanium, chromium, cobalt, nickel, copper, zinc, niobium, molybdenum, silver, and tantalum. Additional cold spray application materials may include powder feedstock selected from the group of Fe, Ni, and/or Cr containing metal alloy powders including 304/304L Stainless Steel, 316/316L/316Ti Stainless Steel, 904L Stainless Steel, 321 Stainless Steel, 410 Stainless Steel, 2205 duplex stainless steel, Alloy C-276, Alloy K-400, Alloy K-500, Alloy 22, Alloy 59, Alloy 600, Alloy 625, Alloy 718, or other Ni—Cr—Mo alloys. Some of the most suitable materials for the techniques of the disclosure include a Ni—Cr—Mo pure ternary alloy having approximately 59 percent to approximately 64 percent Ni, approximately 20 percent to approximately 23 percent Cr, and approximately 16 percent to approximately 18 percent Mo, which is commonly referred to as Alloy 59. The cold spray application material may utilize powder feedstock containing materials having high neutron absorption cross-section, such as those containing boron, gadolinium, and hafnium. Further, the cold spray application material may utilize ceramic hard phase powders including ceramic materials selected from the metallic carbides, including: chromium carbide, tungsten carbide, titanium carbide, molybdenum carbide, hafnium carbide, niobium carbide, tantalum carbide, tantalum niobium carbide, zirconium carbide, vanadium carbide, boron carbide, lanthanum carbide, manganese carbide, silicon carbide, tungsten tantalum carbide, tungsten titanium carbide, and tungsten titanium tantalum carbide. Ceramic materials may be selected from the metallic oxides, including aluminum oxide, aluminum titanate, chromium oxide, yttrium oxide, zirconium oxide, titanium dioxide, silicon dioxide, magnesium oxide, bismuth oxide, cesium oxide, cobalt oxide, copper oxide, iron oxide, gallium oxide, hafnium oxide, niobium oxide, tantalum oxide, tin oxide, zinc oxide, and manganese oxide. Some of the most highly suitable materials utilizing the ceramic hard phase may comprise the metal carbides of chromium, tungsten, niobium, tantalum, and hafnium, and metal oxides of zirconium and aluminum. Ceramic materials with high neutron absorption cross-sections may also be utilized, and may include boron carbide, boron nitride, gadolinium oxide, and hafnium carbide. The hard phase ceramic additions may be added, blended, milled, or otherwise included in the aforementioned metal matrix materials for cold spray usage in the implementation of the disclosure. The techniques of the present disclosure may be utilized for creating embedded flaw-type repairs in which the flaw in the container surface is substantially completely encased by the material of the cold spray coating, which may mitigate further damage to the perimeter wall of the HWC at the damage site. Techniques of the disclosure may be implemented on a HWC prior to placement of the HWC into service as a storage container in order to mitigate or resist corrosion and other damage to the container surface of the HWC. The techniques may also be adapted to use on HWC which have been placed in service as a storage container and contain hazardous material for purposes of repairing existing damage to the container surface of the HWC such as, for example, pitting, cracking, fretting, scratching, or other corrosion or damage, as well as mitigation of future damage. Techniques of the disclosure may be implemented to apply cold spray material within the interior space of the overpack, and may be utilized with horizontally-oriented DCSS and vertically-oriented DCSS. The nozzle of the cold spray applicator may be moved in a pattern over the container surface to create a patch of cold spray coating on the surface. In some of the implementations of the disclosure, the cold spray coating is applied over the welded joints and heat affected areas adjacent to the welded joints, and may include circumferential and longitudinal welds on the HWC. In further implementations, the cold spray coating may be applied over the entire, or substantially the entire, outer surface of the HWC. In such implementations, the nozzle of the applicator may be moved in a substantially linear pattern generally corresponding to the location of the welded joint. In some implementations of the disclosure, the cold spray coating is applied on the container surface at sites of pitting, cracking, fretting, scratching, or other corrosion or damage sites or sites to repair and mitigate further corrosion. In such implementations, the nozzle of the applicator may be moved in a pattern which cycles back and forth in adjacent lines over the area of the container surface to be treated. In general, the present disclosure may provide a method of forming a coating on at least a portion of a hazardous waste container (HWC) which has a perimeter wall with a container surface. The HWC may be positioned in an overpack container, and the overpack container may have an inner surface which defines a chamber for receiving the HWC. An annular gap may be formed between the container surface of the HWC and the inner surface of the overpack container. The method may include providing the HWC, and the HWC may be in a pre-service condition without hazardous contents, or may be in an in-service condition with hazardous contents. An in-service HWC may be partially or fully positioned in the overpack container. The method may also include providing a cold spray application system which may include a cold spray apparatus which is configured to generate a high-pressure gas flow carrying particles to impact the container surface of the HWC at a contact spot on the container surface to thereby form a coating on the container surface. The cold spray apparatus may be configured to generate a substantially linear flow of the particles against the container surface at or about the contact spot. Illustratively, the cold spray apparatus may comprise a gas supply which is configured to supply a gas for use in the cold spray process in which may be supplied at a high pressure. The cold spray apparatus may additionally include a gas control module which is configured to divide the gas supply into a process gas flow and a carrier gas flow, and a heater module may be configured to heat the process gas flow. A powder feeding module of the cold spray apparatus may be configured to feed particles of a cold spray powder into the carrier gas flow, and a mixing module may be configured to mix the heated process gas flow and the powder—containing carrier gas flow together into a combined gas flow. A nozzle of the cold spray apparatus may have an outlet from which a stream of gas and powder particles exits the cold spray apparatus to the contact spot on the container surface of the HWC. The outlet of the nozzle may be positionable in opposition to a desired location for the contact spot on the container surface. The nozzle may receive the combined gas flow from the missed mixing module via a conduit connecting the nozzle to the mixing module. The cold spray application system may include a mobile applicator apparatus which is configured to carry at least the nozzle of the cold spray apparatus to a cold spray application site such that the contact spot of the cold spray apparatus generally aligned with the application site. The mobile applicator apparatus may comprise a mobile base which may include a frame, a plurality of wheels which are rotatably mounted on the frame, with at least one of the wheels having an ability to adhere (or otherwise be attracted) to the container surface of the HWC. The mobile base may also include a motivating element operatively connected to at least one of the wheels to cause rotation of the wheel and movement of the mobile base across the container surface of the HWC. Illustratively, the motivating element may comprise a motor, although the motor may be powered in other ways including utilizing pneumatic power or hydraulic power. Methods of the present disclosure may also include identifying a compromised region on the container surface of the perimeter wall of the HWC. The compromised region may include a welded joint in the perimeter wall, and may extend to a heat affected zone (HAZ) adjacent to the welded joint, and the compromised region may include a damage site which may have been affected or created by corrosion of the perimeter wall of the HWC. Additionally, the methods may include impacting a substantially linear flow of the particles of the cold spray powder against an area in or adjacent to the compromised region of the container surface in a manner that is effective to cause at least some of the particles of the powder to bond to the container surface of the wall to produce a coating on the area of the compromised region. This may include aligning the contact spot of the cold spray apparatus with the area in or adjacent to the compromised region. Further, the methods may include moving the substantially linear flow of particles in a direction that is substantially parallel to the container surface of the perimeter wall to cause the particles of the powder to impact an additional area in or adjacent to the compromised region of the container surface in order to cause the particles of the powder to bond to the surface of the additional area of the compromised region. The techniques of the present disclosure may also be utilized for surface preparation while employing sub-optimal processing conditions such that the powder particles do not reach critical velocity or bond. This technique may remove oxidation, debris, corrosion, and other contamination from the surface and provide an ideal surface cleanliness and roughness to accept cold spray coating. This technique may improve bonding of the coating to the substrate and eliminate corrosion concerns at the interface from entrapped corrosive species. It should be appreciated that in the foregoing description and appended claims, that the terms “substantially” and “approximately,” when used to modify another term, mean “for the most part” or “being largely but not wholly or completely that which is specified” by the modified term. It should also be appreciated from the foregoing description that, except when mutually exclusive, the features of the various embodiments described herein may be combined with features of other embodiments as desired while remaining within the intended scope of the disclosure. Further, those skilled in the art will appreciate that steps set forth in the description and/or shown in the drawing figures may be altered in a variety of ways. For example, the order of the steps may be rearranged, substeps may be performed in parallel, shown steps may be omitted, or other steps may be included, etc. In this document, the terms “a” or “an” are used, as is common in patent documents, to include one or more than one, independent of any other instances or usages of “at least one” or “one or more.” In this document, the term “or” is used to refer to a nonexclusive or, such that “A or B” includes “A but not B,” “B but not A,” and “A and B,” unless otherwise indicated. With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of the disclosed embodiments and implementations, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art in light of the foregoing disclosure, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present disclosure. Therefore, the foregoing is considered as illustrative only of the principles of the disclosure. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the disclosed subject matter to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to that fall within the scope of the claims.
	claims	1. A process for operating a nuclear reactor with a capability to store energy and deliver electricity When needed, the process comprising:removing heat from a core of a nuclear reactor via a circulating heat transfer medium;transferring the heat transfer medium to a storage system; andstoring heat from the heat transfer medium in the storage system; wherein the heat storage system comprises one of at least one tank and a set of pipes and contains or is filled with high temperature resistant solids through which the heat transfer medium from the nuclear reactor is passed in one direction; whereby said solids are heated by the heat transfer medium; anddelivering the stored heat to a power-generating device when needed. 2. The process of claim 1, wherein the heat transfer medium is a compressed gas. 3. The process of claim 2, wherein the compressed gas is helium. 4. The process of claim 1, wherein the heat transfer medium is one of a liquid and a gas. 5. The process of claim 1, wherein the heat transfer medium is hot gas from the nuclear reactor. 6. The process of claim 1, wherein a section of an end of the at least one tank or set of pipes remains cool such that the gas exits the at least one tank or set of pipes at a lower temperature and is recycled to a reactor core. 7. The process of claim 1, wherein the heat storage system stores heat until the heat is needed, wherein when the heat is needed, a gas is passed in a direction counter to a direction of the heat transfer medium passing through the heat transfer system, is heated, and fed to the power generating device, whereby a constant temperature of the gas delivered to the power generating device is maintained. 8. The process of claim 1, wherein the heat storage system comprises a storage vessel structured and configured such that heat is absorbed in the storage vessel and spreads through the storage vessel in a relatively sharp front. 9. The process of claim 8, wherein the relatively sharp front has a width that is less than one tenth of a length of the storage vessel. 10. The process of claim 1, wherein the heat storage system is at least one of:structured and arranged to provide recuperative heat exchange;structured and arranged to provide heating whenever heat is available; andstructured and arranged to provide heat recovery when needed to supply variable loads and counter current streams which have different velocities. 11. The process of claim 1, further comprising compressing the heat transfer medium and transferring heat from the heat transfer medium to a gas of a same composition but at lower pressure. 12. The process of claim 11, further comprising utilizing one circuit to deposit the heat in the heat storage system and another separate circuit to recover the heat and transfer the heat to the power-generating device. 13. The process of claim 11, wherein the lower pressure comprises between about 3 atm and about 30 atm. 14. The process of claim 1, wherein the power-generating device is at least one of a steam power plant or a gas turbine. 15. The process of claim 1, wherein the heat transfer medium comprises one of a liquid molten salt and a liquid molten metal. 16. The process of claim 1, further comprising storing a hot metal in an insulated tank and transferring the hot metal, when not needed for power generation, to a storage vessel, and when needed, using the hot metal to provide heat to the power-generating device. 17. The process of claim 1, Wherein the power-generating device comprises a steam power plant configured for a high turndown ratio and fast response. 18. The process of claim 1, wherein the power-generating device is capable of meeting a maximum variable load expected when the load is larger than the rated capacity of a nuclear power plant utilizing the nuclear reactor, whereby the nuclear power plant can operate at the larger than the rated capacity for a time period and using the stored heat. 19. A method of storing heat, comprising:moving a portion of a heated fluid from at least one reactor core to at least one tank having solid media structured and arranged therein in order to store heat;storing, in the solid media, heat from the portion of the heated fluid; andtransferring the stored heat from the solid media to a fluid, the fluid being selected from fluids that can be used as heat transfer media. 20. The method of claim 19, wherein the heated fluid and the fluid each comprise a compressed gas. 21. The method of claim 20, wherein the compressed gas comprises helium.
053713630	summary	BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting radiation within a pipe. More specifically, it relates to a device that is pulled through embedded piping to perform radiation surveys therein. 2. The Prior Art Nuclear facilities within the United States are licensed for operation by the Nuclear Regulatory Commission (NRC). The NRC specifies radiation contamination limits, for example, radioactive contamination limits that must be satisfied prior to termination of an NRC license. Modern nuclear power stations contain thousands of feet of exposed and embedded piping that must be surveyed in order to determine radioactive contamination levels. The cost of removing this piping is many millions of dollars, and therefore it would be advantageous to survey the internal pipe surfaces while the pipes remain embedded, for the purpose of allowing unconditional release of those pipes. The radiation survey is most effectively carried out by a pipe crawler or a device with radiation sensors that is located within the pipe. These devices are equipped with a variety of detectors, to count alpha, beta particles and/or gamma rays. A different size pipe crawler is required to survey each size of pipe and even each schedule of pipe size. Numerous patents have been issued pertaining to equipment for testing the integrity of pipes and pipe joints. For example, U.S. Pat. No. 4,131,081 to Muller et al, U.S. Pat. No. 4,548,785 to Richardson et al, and European Patent Application 039,922 disclose devices for ultrasonically inspecting pipes. U.S. Pat. No. 4,581,938 to Wentzell, U.S. Pat. No. 5,138,644 to McArdle et al, French Patent 2,652,650 and European Patent Application 078,072 disclose various other types of scanning and measuring equipment for pipes. However, none of these patents addresses the specific problems associated with detecting radiation within pipes. Therefore, it would be advantageous to have a device that can pass within piping and detect radiation contamination on the internal surfaces of those pipes. It would be further advantageous to have a device that can perform detailed radiological surveys at precise locations of internal pipe surfaces. It would further be advantageous to be able to survey different size pipes and different schedules of pipes. SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a device for detecting radiation within a pipe that can be moved through the pipe. It is a further object of the present invention to provide such a device that can perform detailed radiological surveys at precise locations of internal pipe surfaces. It is a further object of the present invention to provide a device for conducting surveys in a variety of pipe sizes with detectors in the precise geometry required to satisfy the U.S. government criteria for the unconditional release of those pipes. It is yet another object of the present invention to provide a device in which the conditions and results of the surveys can be fully recorded and documented for inspection and record retention purposes. These and other related objects are achieved according to the invention by a device for detecting radiation on an interior pipe surface, including a carriage movable through the pipe hat has a longitudinal central axis and radii extending between the longitudinal central axis and the pipe. The device includes means for positioning the carriage centrally within the pipe. A set of radiation sensors are mounted about the central axis for detecting radiation on the interior pipe surface. The device further includes indexing means for rotating the sensor a fraction of the angle between adjacent sensors, so that a circumferential strip on the interior of the pipe in sensed. Cables are coupled to the device for moving it through the pipe and for transmitting sensor data from the device. The device maintains the radiation sensors in the geometry required for unconditional release surveys. In smaller sized pipes, indexing of the sensors is not possible due to the limited diameter of the pipes. In an alternate embodiment, there is provided a device for detecting radiation on the interior of these smaller diameter pipes. The device includes two or more carriages coupled in spaced relation along the central axis of the device and adapted for movement through the pipe. The device includes two or more sets of sensors. Each set of sensors is mounted on one of the carriages. Each set of sensors has an angular displacement about the longitudinal central axis, with respect to the other sets of sensors. The angular displacement is dependent on the number of carriages and the number of sensors per set, so that the entire interior pipe surface is covered as the device is moved through the pipe.
	claims	1. An exposure apparatus comprising:a mask having a pattern to be projected on an exposed object;a scan line set means for setting a plurality of scan lines to be scanned by a charged particle beam on said mask, and;a charged particle beam scan means for performing interlaced-scanning by number of overjumped lines being possible to control rise in temperature of said mask due to overlapping of said charged particle beam, and for repeating said interlaced-scanning for said overjumped lines to scan all said scan lines. 2. An exposure apparatus as set forth in claim 1, wherein said charged particle beam scan means performs said interlaced-scanning by said number of overjumped lines being possible to minimize rise in temperature of said mask by reducing overlapping of said charged particle beam, and by assuring time required for once interlaced-scanning of said mask. 3. An exposure apparatus as set forth in claim 1, whereinsaid scan line set means sets a plurality of said scan lines arranged at an interval larger than a size of said pattern formed on said mask, and;said charged particle beam scan means scans with said charged particle beam having beam diameter larger than said interval of said scan lines. 4. An exposure apparatus as set forth in claim 1, wherein said charged particle beam scan means performs repeatedly interlaced-scanning of said charged particle beam in a fixed direction. 5. An exposure apparatus as set forth in claim 1, wherein said charged particle beam scan means performs interlaced-scanning of said charged particle beam repeatedly in a fixed direction and in a direction opposite to said fixed direction. 6. An exposure apparatus as set forth in claim 5, wherein said charged particle beam scan means performs interlaced-scanning repeatedly in said fixed direction and in said opposite direction to said fixed direction by the number of overjumped lines about twice the number being possible to minimize rise in temperature. 7. An exposure apparatus as set forth in claim 1, wherein said mask is a stencil mask having said pattern formed by an aperture on a thin film. 8. An exposure apparatus as set forth in claim 7, wherein said mask further comprises a beam portion reinforcing strength of said thin film and sectioning said thin film. 9. An exposure apparatus as set forth in claim 7, wherein said scan line set means sets a plurality of scan lines having length of 1.5 times or more and less than double size of a unit exposed region of said exposed object. 10. An exposure apparatus as set forth in claim 1, wherein said mask is an equal scale mask that is arranged close to said exposed object and formed with a pattern to be projected to said exposed object by an equal scale. 11. An exposure method comprising:a step of setting a plurality of scan lines to be scanned by a charged particle beam on a mask formed with a pattern to be projected to an exposed object;a step of performing interlaced-scanning by number of overjumped lines being possible to control rise in temperature of said mask due to overlapping of said charged particle beam, and;a step of repeating said interlaced-scanning for overjumped lines to scan all said scan lines by said charged particle beam. 12. An exposure method as set forth in claim 11, wherein said interlaced-scanning is performed by said number of overjumped lines being possible to be minimum rise in temperature of said mask by reducing overlapping of said charged particle beam and by assuring time required for single interlaced-scanning of said mask in the step of performing said interlaced-scanning. 13. An exposure method as set forth in claim 11, whereina plurality of said scan lines are set to be arranged at an interval larger than size of said pattern formed on said mask in the step of setting said scan line, and;said interlaced-scanning is performed by charged particle beam having beam diameter larger than said interval of said scan line in the step of performing said interlaced-scanning. 14. An exposure method as set forth in claim 11, wherein interlaced-scanning of said charged particle beam in a fixed direction is performed repeatedly in the step of repeating said interlaced-scanning. 15. An exposure method as set forth in claim 11, wherein in the step of repeating said interlaced-scanning, interlaced-scanning of said charged particle beam is performed repeatedly in a fixed direction and in a direction opposite to said fixed direction. 16. An exposure method as set forth in claim 15, wherein interlaced-scanning is performed repeatedly in said fixed direction and in said opposite direction to said fixed direction by number of overjumped lines about twice the number being possible to minimize rise in temperature. 17. An exposure method as set forth in claim 11, wherein a stencil mask formed with an aperture pattern on a thin film is used as said mask. 18. An exposure method as set forth in claim 17, wherein said stencil mask is formed with a beam portion reinforcing strength of said thin film and sectioning said thin film. 19. An exposure method as set forth in claim 11, wherein a plurality of scan lines having length of 1.5 times or more and less than double size of a unit exposed region of said exposed object is set in the step of setting said scan lines. 20. An exposure method as set forth in claim 11, wherein said mask is formed with said pattern to be projected to said exposed object by an equal scale. 21. A semiconductor device production method, forming a circuit pattern of a semiconductor device, by projecting a pattern on a resist formed on a substrate and by using said resist after projecting a pattern to process said substrate, a semiconductor device production method comprising:a step of setting a plurality of scan lines to be scanned by a charged particle beam on a mask formed with a pattern to be projected to an exposed object;a step of performing interlaced-scanning by number of overjumped lines being possible to control rise in temperature of said mask due to overlapping of said charged particle beam, and;a step of repeating said interlaced-scanning for said overjumped lines to scan all said scan lines by said charged particle beam. 22. A semiconductor device production method as set forth in claim 21, wherein said interlaced-scanning is performed by said number of overjumped lines being possible to minimize rise in temperature of said mask by reducing overlapping of said charged particle beam, and by assuring time required for once interlaced-scanning of said mask in the step of performing said interlaced-scanning. 23. A semiconductor device production method as set forth in claim 21, whereina plurality of said scan lines arranged at an interval larger than a size of said pattern formed on said mask are set in a step of setting said scan lines, and;said charged particle beam having beam diameter larger than said interval of said scan lines are used in a step of performing said interlaced-scanning. 24. A semiconductor device production method as set forth in claim 21, wherein interlaced-scanning of said charged particle beam is performed repeatedly in a fixed direction in a step of repeating said interlaced-scanning. 25. A semiconductor device production method as set forth in claim 21, wherein interlaced-scanning of said charged particle beam is performed repeatedly in a fixed direction and in a direction opposite to said fixed direction in a step of repeating said interlaced-scanning. 26. A semiconductor device production method of a as set forth in claim 25, wherein interlaced-scanning is performed repeatedly in said fixed direction and in said opposite direction to said fixed direction by the number of overjumped lines about twice the number being possible to minimize rise in temperature in a step of repeating interlaced-scanning in said fixed direction and in said opposite direction to said fixed direction.
	abstract	The method includes assessing operational characteristics of the fuel assembly, the assessing including determining if the fuel assembly is to be placed in a controlled location in the reactor core, a controlled location being positioned adjacent to a control blade that is to be utilized, and configuring the sidewalls of the outer channel by making at least a first select sidewall of the outer channel a reinforced sidewall, the remaining sidewalls of the outer channel, other than the at least a first select sidewall, being non-reinforced sidewalls. The entirety of the reinforced sidewall as a whole is at least one of thicker and made from a material that is more resistant to radiation-induced deformation as compared to an entirety of the non-reinforced sidewalls.
060312378	description	Examples embodying the present invention are given below, but those examples are by no means construed to restrict the invention. EXAMPLE 1 Composition of the Phosphor Sheet (layer) ______________________________________ Stimulable phosphor (BaFBr.sub.0.85 I.sub.0.15 :Eu.sup.2+ ) 200 g Binder: Polyurethane elastomer (Kuramiron U-8165 8.0 g (solid), product of Kuraray Co., Ltd.; Aromatic polyurethane having a repeating unit of dimethylphenylmethane diisocyanate; Vicat softening point: 69.degree. C.) Anti-yellowing agent: Epoxy resin (EP 1001 2.0 g (solid), product of Yuka Shell Epoxy Kabushiki Kaisha) Radical scavenger: Hindered amine compound 0.16 g (Mark LA-77, product of Adeka Argas Chemical CO., Ltd.) ______________________________________ The above composition was placed in tetrahydrofuran and dispersed by means of a propeller mixer to give a coating dispersion of a viscosity of 30 PS (at 25.degree. C.) in which the ratio of binder to phosphor was 1/20. The coating dispersion was coated on a polyethylene terephthalate temporary support (thickness: 150 .mu.m) having a silicon release coating. The coated layer was dried to give a stimulable phosphor sheet having a thickness of 150 .mu.m. Composition of the Undercoating Layer ______________________________________ Binder: Soft acryiic resin (solid) 90 g Nitrocellulose (solid) 30 g ______________________________________ The above composition was placed in methyl ethyl ketone and dispersed by means of a propeller mixer to give a coating dispersion for the undercoating layer of a viscosity in the range of 3 to 6 PS (at 25.degree. C.). The prepared coating dispersion was coated on a polyethylene terephthalate permanent support (thickness: 300 .mu.m) horizontally placed on a glass plate. The coated layer was dried to provide an undercoating layer (thickness: 15 .mu.m) on the permanent support. On the undercoating layer thus formed on the permanent support, the phosphor sheet was placed and then compressed by means of a calendar roll. The compression treatment was sequentially carried out under the conditions as follows: pressure: 500 kgw/cm.sup.2 ; temperature: 75.degree. C. (upper roller) and 25.degree. C. (lower roller); and moving speed: 0.3 m/min. The phosphor sheet was completely fixed on the support by the treatment. Composition of the Protective Film ______________________________________ Fluororesin: Fluoroolefin-vinyi ether copolymer 50 g (Lumiflon LF-504x (40 wt.% solution), product of Asahi Glass Co., Ltd.) Cross-linking agent: polyisocyanate (Olestar 9 g NP38-70s (70 wt. % solution), product of Mitsui Toatsu Chemicals, Inc.) Alcohol modified-silicone resin (X-22-2809 0.5 g (66 wt. % solution), product. of The Shin- Etsu. Chemical Co., Ltd.) Catalyst: dibutyltin dilaurate (KS1260, product of 3 mg Kyodo Chemical Co., Ltd.) ______________________________________ The above composition was dissolved in a mixed solvent of methyl ethyl ketone and cyclohexane (2:8, by volume) to prepare a coating solution of a viscosity in the range of 0.2 to 0.3 PS (at 25.degree. C.). The coating solution was applied on the phosphor layer using a doctor blade, and then heated at 120.degree. C. for 30 minutes to cure and dry the coated layer film. Thus, a protective film (thickness: 3 .mu.m) was formed on the phosphor layer. Composition of Edge Coating Film ______________________________________ Silicone polymer: Polyurethane having a repeating 70 g unit of polydimethylcyclohexane (Diaromer SP-3023 (15 wt. % methyl ethyl ketone-toluene mixed solution), product of Dainichiseika Color & Chemicals Mfg. Co., Ltd.) Cross-linking agent: polyisocynate (Crossnate 3 g D-70 (50 wt. % solution), product of Dainichiseika Color & Chemicals Mfg. Co., Ltd.) Anti-yellowing agent: Epoxy resin (EP 1001 0.6 g (solid), product of Yuka Shell Epoxy Kabushiki Kaisha) Alcohol modified-silicone (X-22-2809 0.2 g (66 wt. % solution), product of The Shin- Etsu Chemical Co., Ltd.) ______________________________________ The composition was dissolved in 15 g of methyl ethyl ketone to prepare a coating solution for edge coating film. The solution was coated on the edge (side surface) of the above-formed multi-layered body consisting of the support, the undercoating layer, the phosphor layer and the protective film. Thereafter, the coated solution was well dried to give a hard edge coating film (thickness: 25 .mu.m). Thus, a radiation image storage panel consisting of the support, the undercoating layer, the phosphor layer, the protective film and the edge coating film was produced. EXAMPLE 2 The procedures of Example 1 were repeated except that the radical scavenger of hindered amine compound (0.16 g of Mark LA-77) was replaced with a radical scavenger of hindered phenol compound (0.20 g of ADK SIAB A0-70, product of Adeka Argas Chemical Co., Ltd.), to produce a radiation image storage panel consisting of the support, the undercoating layer, the phosphor layer, the protective film and the edge coating film. EXAMPLE 3 The procedures of Example 1 were repeated except that the radical scavenger of hindered amine compound (0.16 g of Mark LA-77) was replaced with a radical scavenger of hindered amine compound (0.17 g of Sanol LS-765, product of Sankyo CO., Ltd.), to produce a radiation image storage panel consisting of the support, the undercoating layer, the phosphor layer, the protective film and the edge coating film. EXAMPLE 4 The procedures of Example 1 were repeated except that the phosphor sheet was prepared in the below-mentioned manner, to produce a radiation image storage panel consisting of the support, the undercoating layer, the phosphor layer, the protective film and the edge coating film. Composition of the Phosphor Sheet (layer) ______________________________________ Stimulable phosphor (BaFBr.sub.0.85 I.sub.0.15 :Eu.sup.2+) 200 g Binder 1: Polyurethane elastomer (P-22 (solid), 8.0 g product of Nippon Miractran Co., Ltd.; Aromatic polyurethane having a repeating unit of dimethylphenylmethane diisocyanate; Vicat softening point: 64.degree. C.) Anti-yellowing agent:.Epoxy resin (EP 1001 2.0 g (solid), product of Yuka Shell Epoxy Kablishiki Kaisha) Radical. scavenger: Hindered amine compound 0.16 g (Mark LA-77, product of Adeka Argas Chemical Co., Ltd.) ______________________________________ The composition was placed in tetrahydrofuran and dispersed by means of a propeller mixer to give a coating dispersion of a viscosity of 30 PS (at 25.degree. C.) in which the ratio of binder to phosphor was 1/20. The coating dispersion was coated on a polyethylene terephthalate temporary support (thickness: 150 .mu.m) having silicon release coating. The coated layer was dried to give a stimulable phosphor sheet having a thickness of 150 .mu.m. COMPARISON EXAMPLE 1 The procedures of Example 1 were repeated except that the radical scavenger was not employed, to produce a radiation image storage panel consisting of the support, the undercoating layer, the phosphor layer, the protective film and the edge coating film. COMPARISON EXAMPLE 2 The procedures of Example 2 were repeated except that the radical scavenger was not employed, to produce a radiation image storage panel consisting of the support, the undercoating layer, the phosphor layer, the protective film and the edge coating film. COMPARISON EXAMPLE 3 The procedures of Example 1 were repeated except that the radical scavenger was not employed and an aliphatic polyurethane (T5265H, product of Dainippon Ink & Chemicals, Inc.) was used as a polyurethane elastomer, to produce a radiation image storage panel consisting of the support, the undercoating layer, the phosphor layer, the protective film and the edge coating film. EVALUATION OF RADIATION IMAGE STORAGE PANEL With respect to each of the radiation image storage panels prepared in the above examples, durability against both repeated conveying and light was evaluated in the following manner. 1) Durability Against Repeated Conveying The radiation image storage panel was cut to prepare a rectangular sample piece (100 mm.times.250 mm). The sample piece was repeatedly transferred in a conveying-durability test machine (shown in U.S. Patent No. 5,641,968) until cracks occurred in the phosphor layer. The durability of the panel against repeated conveying was evaluated by the number of the repetition of the above transferring in the test machine. The results are shown in Table 1. 2) Durability Against Light (light-resistance) The phosphor layer of the radiation image storage panel was irradiated with the light from a sodium lump at an illuminance of 200,000 lux for 30 hours. Then, the sensitivity of the panel was measured and compared with that having received no irradiation. The reduction ratio of the sensitivity was calculated to evaluate the light-resistance. The results are shown in Table 1. TABLE 1 ______________________________________ repeated conveying light-resistance (repetition number) (reduction ratio) ______________________________________ Example 1 6000 times 1.5% Example 2 6000 times 2.2% Example 3 6000 times 2.50% Example 4 8000 times 1.8% Com. Example 1 6000 times 12.3% Com. Example 2 8000 times 13.5% Com. Example 3 4000 times 1.8% ______________________________________ From the results shown in Table 1, it has been confirmed that the radiation image storage panels of the invention exhibit excellent durability against not only repeated conveying but also light.
040244024	abstract	A specimen cartridge is provided for a particle beam device, such as an electron microscope or the like equipped with a specimen table adjustable transverse to the beam axis, the cartridge being insertable into the table along an axis parallel to the beam axis. The cartridge has a conical member having a longitudinal axis and a specimen holder having a plurality of openings for receiving a corresponding number of specimens is secured to the conical member. The holder is rotatable about an axis of rotation eccentric to the longitudinal axis of the conical member.
040615332	claims	1. In a control system for a nuclear power producing unit comprising a pressurized water reactor, a once-through steam generator provided with feedwater supply means, a turbine-generator supplied with steam from the steam generator and means maintaining a flow of pressurized water through the reactor and steam generator, the combination comprising; means generating a feed forward control signal proportional to the desired power output of the power producing unit, a second means for adjusting the reactor heat release, a third means for adjusting the rate of flow of feedwater to the steam generator, said second and third means solely responsive to and operated in parallel from said feed forward control signal whereby the reactor heat release and the rate of flow of feedwater to the steam generator are each maintained in a discrete functional relationship to said feed forward control signal. 2. In a control system as set forth in claim 1 further including a fourth means for adjusting the rate of flow of steam from the steam generator to the turbine, said fourth means solely responsive to and operated in parallel with said second and third means from said feed forward control signal. 3. In a control system as set forth in claim 1 further including a function generator responsive to said feed forward signal and producing a modified feed forward signal, said second means responsive to said modified feed forward signal. 4. In a control system as set forth in claim 1 further including means modifying the response of said second means to said feed forward signal in proportion to the time integral of the difference between the desired and actual power output of the power producing unit. 5. In a control system as set forth in claim 2 wherein the nuclear power producing unit has a plurality of critical parameters, further including means modifying the discrete response of said second, third and fourth means in proportion to changes in the magnitudes of said plurality of parameters. 6. In a control system as set forth in claim 1 further including means modifying the response of said third means to said feed forward signal in proportion to the time integral of the deviation in the average of the temperatures of the said pressurized water entering and leaving the reactor from set point. 7. In a control system as set forth in claim 6 further including means modifying the response of said third means in accordance with the average of the temperatures of the said pressurized water entering and leaving the reactor from set point in proportion to the difference between the desired and actual power output of the power producing unit. 8. In a control system as set forth in claim 1 further including means modifying the response of said third means to said feed forward signal in functional relationship to changes in the rate of said pressurized water flow through the steam generator. 9. In a control system as set forth in claim 1 further including means modifying the response of said third means to said feed forward control signal in proportion to changes in the temperature of the feedwater entering the steam generator. 10. In a control system as set forth in claim 1 wherein the nuclear power producing unit includes a second once-through steam generator provided with feedwater supply means and supplying steam to the turbine-generator and means maintaining said pressurized water flow through the reactor and said second steam generator, the combination further comprising; means for maintaining the total rate of feedwater flow to said generators in a discreet functional relationship to said feed forward signal. 11. In a control system as set forth in claim 10 further including means for adjusting the relative rates of feedwater flow to the steam generators in accordance with the difference in the average temperatures of the said pressurized water entering and leaving said first named steam generator and said second steam generator. 12. In a control system as set forth in claim 11 further including means adjusting the relative rates of feedwater flow to the steam generators in accordance with the time integral of the difference in said average temperatures. 13. In a control system as set forth in claim 10 further including means for adjusting the relative rates of feedwater flow to the steam generators in accordance with changes in the relative rates of said pressurized water flow through the steam generators. 14. The combination as set forth in claim 10 further including means for adjusting the relative rates of feedwater flow to the steam generators in proportion to the difference in temperatures of the feedwater supplied the steam generators. 15. The combination as set forth in claim 10 further including means for adjusting the relative rates of feedwater flow to the steam generators in accordance with the algebraic sum of the difference in the average of the temperatures of the said pressurized water entering and leaving the steam generators, the relative rates of said pressurized water flow through the steam generators and the difference in temperature of the feedwater supplied the steam generators.
	abstract	An object of this invention is to provide a charged particle beam apparatus that is capable of handling samples without adhering impurities onto the samples. In a scanning electron microscope in which a lubricant was coated on a sliding portion of a movable member that moves inside a vacuum chamber, a substance from which low molecular components were removed is used as the lubricant. It is thus possible to inhibit sample contamination and suppress the occurrence of defects in a process following measurement of the samples.
	summary
	claims	1. A method of pressurizing a nuclear core component having a tubular cladding with an upper and lower end, comprising the steps of:closing off a lower end of the cladding with a lower end plug fixture configured to form a gas tight seal;loading an active element into the lower end of an interior of the cladding above the lower end plug leaving an empty plenum in the interior of the cladding above the active element;inserting a spring within the empty plenum between the upper end of the cladding and the active element, the spring being configured to bias the active element towards the lower end plug fixture when the upper end of the cladding is closed off by an upper end plug fixture;closing off the upper end of the cladding with the upper end plug fixture comprising an upper end plug external piece and an upper end plug internal piece, the upper end plug internal piece configured to slide within a through opening in the upper end plug external piece and have a lower end that biases the spring towards the active element when the upper end plug fixture forms a gas tight seal at an interface of the cladding and the upper end plug at least partially closing off the upper end of the cladding, the through opening and the upper end plug internal piece configured so an upper portion of the upper end plug internal piece fits within the through opening but cannot pass through and out of an upper portion of the through opening and the spring is configured to support the upper end plug internal piece within the through opening, the upper end plug internal piece and the through opening forming a substantially gas tight seal at an upper limit of travel of the upper end plug internal piece through the through opening and a gas communication path at a point below the upper limit of travel;placing at least the upper end of the cladding, with the upper end plug fixture and the lower end plug fixture in place, in a pressure chamber;applying a vacuum to an interior of the cladding;introducing a filler gas into the pressure chamber;raising the pressure of the filler gas within the pressure chamber to a preselected pressure for a given period of time; andsealing the upper end plug internal piece to the upper end plug external piece. 2. The method of claim 1 including the step of permanently sealing the upper end plug fixture and the lower end plug fixture to the cladding. 3. The method of claim 2 including the step of removing the cladding with the upper end plug fixture and the lower end plug fixture from the pressure chamber after the given period of time and wherein the step of permanently sealing the upper end plug fixture and the lower end plug fixture to the cladding is performed after the removing step. 4. The method of claim 3 including the step of permanently sealing the upper end plug internal piece to the upper end plug external piece after the removing step. 5. The method of claim 1 wherein the step of closing off of the lower end of the cladding and the step of closing off of the upper end of the cladding is performed with a clamp or other fixture that forces the upper end plug external piece against the cladding. 6. The method of claim 5 wherein the clamp is a mechanical or hydraulic clamp. 7. The method of claim 1 including the step of placing a binding agent at an interface of a wall of the through opening and an abutting wall of the upper end plug internal piece. 8. The method of claim 7 wherein the binding agent comprises one or more of SiC paste, graphite, silver, titanium or aluminum. 9. The method of claim 1 wherein the step of sealing the upper end plug internal piece to the upper end plug external piece is performed by reducing the pressure of the filler gas within the pressure chamber after the given period of time, or otherwise removing a force pushing against the upper end plug internal piece biasing the upper end plug internal piece into an interior of the cladding. 10. The method of claim 1, prior to the step of introducing the filler gas and subsequent to the step of placing the cladding in the pressure chamber, including the step of drawing a vacuum on the pressure chamber. 11. The method of claim 1 including the step of mechanically attaching the upper end plug external piece to the cladding.
	abstract	Arrangements and devices for reducing and/or preventing wear of a thermal sleeve in a nuclear reactor are disclosed. Arrangements include a first structure provided on or in one the thermal sleeve and a second structure provided on or in the head penetration adapter. At least a portion of the first structure and at least another portion of the second structure interact to resist, reduce, and/or prevent rotation of the thermal sleeve about its central axis relative to the head penetration adapter. Devices include a base for coupling to a guide tube of the reactor and a plurality of protruding members extending upward from the base. Each member having a portion for engaging a corresponding portion of a guide funnel of the thermal sleeve.
043893554	description	DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Nuclear fuel pellets manufactured to fuel nuclear reactors are produced by starting with a uranium dioxide (UO.sub.2) powder (industry has adopted UO.sub.2 although the stoichiometric starting powder can be represented as UO.sub.2.05-2.15) and blending it with a commercially available organic binder powder. The quantity of organic binder is not crucial but it should be in the range of about 0.1 to 0.3% by weight of the blended mixture, the remainder being about 99.7 to 99.9% UO.sub.2, an amount sufficient to hold the powders together during shaping and pressing. Blending time should be sufficient to produce a homogenous mixture. After blending, the blended mixture is shaped and cold pressed into pressed green pellet compacts, the pressing force being that sufficient to compact the powders to approximately 50% of their theoretical mixture density, a determination based upon compact length, diameter and weight. The compacts are then heated and sintered in a microwave induction furnace in a reducing atmosphere consisting essentially of a nitrogen (N.sub.2) and hydrogen (H.sub.2) gas mixture and, more specifically, about a 75% H.sub.2 -25% N.sub.2 gas mixture. However, any reducing atmosphere would be operable. The sintering temperature is in the range of about 1600.degree. C. to 1800.degree. C., and the compacts are held in the microwave furnace in the reducing atmosphere at the sintering temperature for approximately 2 to 6 hours to achieve a compact density of about 95% of theoretical density. Sintering in a reducing atmosphere reduces the hyperstoichiometric starting powder, UO.sub.2.05-2.15, to UO.sub.2. After sintering, the compacts are cooled to approximately room temperature, the cooling being conducted in the reducing atmosphere. After cooling, the compacts are ground to the desired UO.sub.2 finished pellet product. The nuclear pellet fabrication process above described can also be conducted with additional process steps included after the shaping and pressing step but before the sintering step. However, with the additional steps, the above mentioned pressing force becomes that sufficient to compact the powders to approximately 44% of their theoretical mixture density. The additional steps include forcing the compacts through screens to form a granulate and then cold pressing the granulate into pressed pellet compacts, the granulate pressing force being that sufficient to compact the granulate to approximately 50% of theoretical density. Additionally, U.sub.3 O.sub.8 powder can be blended with the UO.sub.2 and organic binder powders in the first step of the fuel preparation process, the U.sub.3 O.sub.8 powder being approximately 5% by weight of the blended mixture, the remainder being about 0.1 to 0.3% binder and about 94.7 to 94.9% UO.sub.2. The U.sub.3 O.sub.8 constituent of the pellet compacts, upon sintering in the reducing atmosphere, is converted to UO.sub.2. It has been determined that uranium oxide with stoichiometries UO.sub.2 through U.sub.3 O.sub.8 directly suscepts to microwave radiation at approximately 2450 MH.sub.Z, the frequency of the standard kitchen-type microwave oven, heating rapidly to very high, red-hot temperatures. It should be understood that, while a conventional microwave oven was selected for use because of its ready availability, other microwave induction furnaces, conventional and non-conventional, operating at different frequencies would also be operable. Other ceramic materials including alumina, silica, niobia, lithia and graphite do not as readily suscept to microwave radiation at 2450 MH.sub.Z. Testing to ascertain that uranium oxide with stoichiometries UO.sub.2 through U.sub.3 O.sub.8 directly suscepts to microwave radiation was conducted by placing green pressed UO.sub.2 pellet compacts into an alumina tube, placing the tube into a conventional 2450 MH.sub.Z microwave oven, providing a means for introducing a reducing atmosphere into the tube, plugging the ends of the tube with refractory insulating material, and heating the tube, with compacts, in the oven in a reducing atmosphere of a N.sub.2 and H.sub.2 gas mixture. Heating was initially conducted for two minutes at a power setting of 20, which means that 100% of the oven power was delivered 20% of the time. The initial power of 20, sufficient to remove most of any contained moisture, was increased to a power setting of 30 and held for five minutes to remove any remaining moisture. The power was then raised to a setting of 70 for ten minutes and then increased to a 100 setting for fifteen additional minutes. The alumina tube itself was transparent to the microwave radiation allowing for passage of the microwave radiation and heating of the compacts from the inside out rather than from the outside in, a characteristic of normal refractory furnaces. Heating to 1370.degree. C. was achieved after only fifteen minutes of operation. A flickering glow from within the tube began about five minutes into the 70 power setting with the glow becoming constant at the full power setting of 100, a sintering temperature of 1620.degree. C. was measured at the outer surface of the tube. The power setting of 100 was held for an additional fifteen minutes and then the compacts were cooled in the oven to about room temperature, the reducing atmosphere being continuously maintained. Compact density measurements were made and are presented as follows: ______________________________________ THEO- RETI- DI- CAL COM- AME- DEN- DEN- PACT TER LENGTH WEIGHT SITY SITY (#) (cm) (cm) (g) (g/cc) (%) ______________________________________ 1 .70 1.04 2.24 5.59 51.00 unsintered (control) 2 .59 .85 2.12 9.12 83.21 sintered 3 .58 .73 1.72 8.91 81.30 sintered 4 .59 .87 2.01 8.45 77.10 sintered ______________________________________ Additional testing was conducted on UO.sub.2 pellet compacts of the size most commonly encountered in nuclear fuel pellet preparation. The testing was conducted as described above except that the sintering time was increased to four hours and the compacts had an inside diameter of approximately 0.3 cm. Compact density measurements were made and are presented as follows: ______________________________________ THEO- RETI- OUTSIDE CAL COM- DIAM- DEN- DEN- PACT ETER LENGTH WEIGHT SITY SITY (# (cm) (cm) (g) (g/cc) (%) ______________________________________ 1 .97 1.05 7.12 10.14 92.54 2 .97 1.11 7.87 10.52 96.02 3 .98 1.11 7.85 10.43 95.14 4 .98 1.04 7.02 9.93 90.57 5 .97 1.04 7.01 10.07 91.92 6 .98 1.08 7.66 10.41 94.98 7 .98 1.10 7.76 10.43 95.19 8 .97 1.17 7.79 9.92 90.48 9 .98 1.14 7.71 9.86 89.95 10 .97 1.11 7.61 10.41 95.01 ______________________________________ Alumina was selected for use in the sintering chamber because it could withstand the high temperatures generated but not interact with the microwave field. Metallic components could therefore not be considered since they reflect microwaves. During the nuclear fuel preparation process, the compacts need not be sealed in alumina tubes, but, alumina boats, vessels or other material invisible to microwave radiation, could be used as the carrying means for the compacts in the microwave induction furnace. Test compacts of uranium dioxide with organic binder, and, uranium dioxide and U.sub.3 O.sub.8 with organic binder, all suscepted to microwave radiation thus demonstrating the microwave induction sintering furnace to be a viable alternative to the refractory-type sintering furnace. Recycling of scrap uranium dioxide is an important adjunct to the nuclear fuel preparation process. During pellet preparation, there is generated a quantity of sintered uranium dioxide pellets and uranium dioxide powder available for recycle. Sintered pellets that do not meet specifications and uranium dioxide powder or grinder sludge generated during the compact grinding step are conveyed, in an alumina boat, vessel or comparable material invisible to microwave radiation, to a microwave induction furnace for reprocessing and recycling. Additionally, any other scrap uranium dioxide could be added and processed in this manner. Heating of the material to its oxidation temperature of at least 200.degree. C. in the microwave furnace is accomplished by microwave radiation in an oxidizing atmosphere, generally, but not limited to, air, wherein UO.sub.2 is oxidized to a U.sub.3 O.sub.8 powder. Specific heating time and temperature are not critical but heating should be conducted for a time sufficient to change the material to a fine black powder, a process that is a function of material mass but is generally accomplished in an approximate temperature range of 400.degree. to 500.degree. C. in approximately 20 to 40 minutes. In the furnace, the pellets are heated to the point where the outer pellet surface oxidizes to U.sub.3 O.sub.8 and separates from the UO.sub.2 inner pellet due to the differences in density between UO.sub.2 and U.sub.3 O.sub.8, the UO.sub.2 being of greater density. With the introduction of fresh, unoxidized surfaces, the process would continue until the entire pellet was oxidized to a black U.sub.3 O.sub.8 powder. The uranium dioxide powder or grinder sludge is already in powder form, therefore, upon heating in the furnace in the oxidizing atmosphere, the sludge would quickly be converted to the U.sub.3 O.sub.8 powder. The oxidized product leaving the furnace is a fine U.sub.3 O.sub.8 powder suitable, after cooling, for blending back with uranium dioxide and organic binder powders in a nuclear fuel pellet preparation process. Heating in the recycling furnace can be continuous or intermittent. Pellet oxidation, however, is enhanced by microwave heating when the power level is alternated, a power on followed by a power off cycle. After a period of power on followed by a period of power off, the UO.sub.2 pellets heat up extremely rapidly when the microwave radiation is restored. Sintered pellets have been completely fragmented by simply turning the microwave source off and on while the pellets are oxidizing. When the UO.sub.2 material has surpassed the oxidation temperature, its susceptance to microwave radiation is very high. Wnen the microwave radiation is interrupted, the material begins to cool, still oxidizing. The material immediately returns to a glowing red temperature when the microwave radiation is reintroduced. The rapid heat-up and cool-down causes tremendous thermal stresses to exist in the pellet structure. The thermal stresses, along with the stresses introduced due to the difference in density between UO.sub.2 and U.sub.3 O.sub.8, cause pellet fracture in a static condition. Fresh surfaces are exposed upon every cooling cycle allowing oxidation to continue to completion. Laboratory testing has established that samples of UO.sub.2 powder placed in a conventional 2450 MH.sub.Z microwave oven directly suscept to microwave radiation in an oxidizing atmosphere. A UO.sub.2 powder sample weighing approximately 5 grams will be glowing red in less than one minute and oxidation will be occurring at all surfaces in contact with air. Testing has also shown that a sintered pellet placed in the microwave field suscepts within approximately 1 to 2 minutes with the pellet breaking up as oxidation progresses. Oxidation of the pellet is enhanced by setting the power level to a power setting of 50. The pellet fractures due to density differences and induced thermal stresses as the microwaves are turned on and are then shut off. A reduced power setting, providing on/off or intermittent microwave radiation, enhanced the oxidation by setting up thermal stresses and density differences causing pellet fracture and increasing the fresh UO.sub.2 surfaces available for oxidation. While in accordance with the provisions of the statutes there is illustrated and described herein a specific embodiment of the invention, those skilled in the art will understand that changes may be made in the form of the invention covered by the claims, and that certain features of the invention may sometimes be used to advantage without corresponding use of the other features.
	description	This invention was made with government support under Contract No. DE-AC07-05ID14517 awarded by the United States Department of Energy. The government has certain rights in the invention. 1. Field of the Invention The present invention relates generally to compositions for decontaminating surfaces and methods of using such compositions to decontaminate surfaces. More particularly, the present invention relates to clay-based compositions and methods of using such clay-based compositions to decontaminate a surface and/or a material having a surface. 2. State of the Art Radioactive, biological, and other unwanted contaminants may adhere to surfaces or penetrate into porous materials upon exposure of the material to such contaminants. Often times, contamination resulting from such exposure is hazardous and must be removed in order to make the material safe for its intended use. For example, materials and surfaces coming in contact with radioactive materials for the production of energy, production and use of radioactive medical devices, and the disposal of radioactive waste often become contaminated with radioactive materials that contact such surfaces. Human exposure to the resulting radioactive contamination on the surface of such materials is undesirable; therefore, contaminated surfaces and materials must be decontaminated before further use or they must be disposed of. In addition, the increased availability of radioactive and bioactive materials has increased the probability that a “dirty-bomb” utilizing such materials may be used as a weapon for terrorist acts or in low-conflict warfare. If employed, weapons utilizing radioactive materials or bioactive materials would cause the spread of radioactive or bioactive contamination within a zone of activation. Materials, such as building materials, exposed to the radioactive or bioactive contamination would become contaminated. In order to safely decontaminate the exposed materials and surfaces, suitable and effective decontamination methods and compositions would need to be employed. Although numerous methods and compositions may exist for removing radioactive contamination or bioactive contamination, many of the decontamination methods are costly or are destructive of the materials being decontaminated. For instance, concrete exposed to radioactive contamination may be decontaminated using active chemical agents and physical scrubbing techniques. Typically, concrete or other porous surfaces contaminated by radioactive materials are decontaminated by physical grit blasting of the surface of the contaminated material and chemical treatment of the surface. Costs associated with such decontamination methods are high, the amount of waste generated by such methods is large, and the waste must be specially disposed of due to the radioactive and hazardous nature of the waste. In addition, such decontamination processes are labor intensive. Further, grit blasting and chemical treatments usually only decontaminate the surface of a material and are rarely capable of treating the bulk of a material or a significant distance beyond surface contamination, if deeper contamination exists. Therefore, it is desirable to develop methods for decontaminating surfaces exposed to radioactive contamination, bioactive contamination, or other forms of contamination. It is also desirable to provide decontamination compositions that may be used to decontaminate surfaces and sub-surfaces of materials that have been exposed to radioactive, bioactive, or other contaminants. Embodiments of the invention include decontamination compositions and methods for decontaminating surfaces and sub-surfaces of contaminated materials. According to some embodiments of the invention, a clay-based decontamination composition may be wetted or swelled with a solution that aids in decontamination of a surface. When applied to the clay-based composition, the solution provides ions to the decontamination composition, which ions may promote ion exchange between a contaminated material and the decontamination composition, allowing the decontamination composition to adsorb contaminants from a material surface to which it is applied. According to other embodiments of the invention, decontamination compositions include clay-based montmorillonite compositions wetted or swelled with a potassium chloride solution. In some embodiments, the montmorillonite composition may include a sodium-montmorillonite or a calcium-montmorillonite composition. Methods for decontaminating surfaces and materials are provided in other embodiments of the invention. In some embodiments, a decontamination composition according to embodiments of the invention is applied to a contaminated surface and allowed to remain on the surface for a period of time before being removed. In other embodiments, a contaminated surface is treated with a solution, such as the solution used to form the decontamination composition, by spraying, wiping, or otherwise applying the solution to the contaminated surface. A decontamination composition according to embodiments of the invention is then applied to the solution treated contaminated surface and allowed to remain there to promote decontamination before being removed. In still other embodiments, a contaminated surface may be treated with a decontamination solution or foam prior to the application of a decontamination composition of embodiments of the invention to the contaminated surface. According to embodiments of the present invention, a contaminated material may be partially or completely decontaminated by the application of a decontamination composition to the material and removal of the decontamination composition from the material. Decontamination compositions according to embodiments of the invention include clay or clay-like compositions wetted with one or more solutions, which compositions are capable of decontaminating a material or surface to which they are applied. According to some embodiments of the invention, a decontamination composition may include a clay-based composition of montmorillonite. In other embodiments, the decontamination composition may also include other materials, components, or compositions, as desired. For example, decontamination compositions may include naturally occurring beidellite minerals, nontronite minerals, sponite minerals, hectorite minerals, sauconite minerals, and other smectite group minerals. Decontamination compositions may also include synthetic materials, such as synthesized smectite clays. Additional materials, solutions, and compositions added to the decontamination composition of embodiments of the present invention may alter the properties of the decontamination composition and in some instances improve the characteristics of the decontamination composition for certain uses. Montmorillonite clay minerals are di-octrahedral layered silicates having an octahedral layer sandwiched between two tetrahedral layers as illustrated in FIG. 1. Montmorillonite may generally be represented by the following formula:(½Ca,Na)0.7(Al,Mg,Fe)4[(Si,Al)8O20](OH)4.Montmorillonite clays have the capacity to expand or swell up to about 18 times their original size when exposed to water or a hydrating solution. Montmorillonite clays exhibit excess negative charges that are generally balanced by adsorbed cations. Typically, montmorillonite clays have a cation exchange capacity of about 0.8 milliequivalents per gram and more than 90 percent of the exchange sites are located within the interlayer, as illustrated in FIG. 1. Additional exchange sites include edge or planar sites, which account for approximately 4 percent of the surface area of the montmorillonite clay composition. The exchange of ions in the montmorillonite clays is based upon the ion size and charge. For monovalent cations in Group 1A of the periodic table, the replacement power increases as follows: Li<Na<K<Rb<Cs. Thus, absorbed sodium (Na) ions in a montmorillonite clay formation could be readily replaced by potassium (K) ions. Similarly, for the divalent cations in Group 2A of the periodic table, the replacement power increases as follows: Mg<Ca<Sr<Ba, resulting in strontium (Sr) ions readily replacing adsorbed calcium (Ca) ions in a montmorillonite clay formation. Naturally occurring montmorillonite clay formations are found in various locations around the world, including France, Italy, and the United States. In some embodiments of the invention, sodium-montmorillonite clays found in the Newcastle formation in the state of Wyoming, United States of America, can be used to form decontamination compositions. Sodium-bentonite clays found in the state of Texas, United States of America, can also be used to form decontamination compositions according to embodiments of the invention. In still other embodiments, clay produced and sold under the name VOLCLAY® SPV 200 by Rennecker Limited of Cleveland, Ohio, may be used to form decontamination compositions of the invention. Results of a chemical analysis of these three clays are shown in Table I. TABLE IVOLCLAY ® Analysis (wt. %)SWY-2Texas Na-bentoniteSPV 200SiO262.963.563.02Al2O319.69.3221.08Fe2O33.352.573.25FeO0.32MgO3.051.792.67CaO1.680.880.65Na2O1.534.062.57K2O0.531.28F0.111P2O50.049S0.05LiO7.3911.65.64sizeMin 65% <74 uMMin 98% <74 uM Further analysis of the SWY-2 clay (sodium-montmorillonite clay from Wyoming) indicates that the cation exchange capacity of that clay is on the order of 76.4 milliequivalents per one-hundred grams of material. The principle exchange cations of the clay are sodium and calcium. In addition, the N2 surface area of the clay composition is about 31.82+/−0.22 m2/g. The octahedral charge is about −0.53, the tetrahedral charge about −0.02, the interlayer charge about −0.55, and the unbalanced charge about 0.05. The determined structure of the SWY-2 clay found in Wyoming is as follows:(Ca0.12Na0.32K0.05)[Al3.01Fe(III)0.41Mn0.01Mg0.54Ti0.02][Si7.98Al0.02]O20(OH)4 In some embodiments of the invention, sodium-montmorillonite clays, such as the SWY-2 clays, are used to form decontamination compositions of the invention. In other embodiments, however, calcium-montmorillonite clays or other montmorillonite clays may be used alone or mixed with sodium-montmorillonite clays to form decontamination compositions. In still other embodiments, the decontamination compositions may include bentonite, illite, smectite clays, or synthesized smectite clays, such as those used with wastewater treatment. The use of synthesized clays to form decontamination compositions of the invention provides for the customization of the clays, such that a particular clay may be formed to adsorb specific ions. According to embodiments of the invention, a decontamination composition is formed by wetting a montmorillonite clay with a solution capable of inducing ion exchange of a contaminant from a surface or sub-surface of a material when the decontamination composition is applied to the material surface. The addition of the solution to the montmorillonite clay forces the montmorillonite clay to expand, resulting in the displacement of cations from the montmorillonite clay and replacement with cations from the solution. The expanded montmorillonite clay may then be applied to a contaminated surface, wherein cation exchange of the contaminants from the contaminated surface into the decontamination composition is induced. For example, a decontamination composition according to embodiments of the invention may be formed by wetting a sodium-montmorillonite clay with a potassium chloride (KCl) solution. The addition of the potassium chloride solution to the sodium-montmorillonite clay causes expansion of the clay and an ion exchange of potassium ions for the sodium ions in the clay. The resulting expanded clay may be used as a decontamination composition according to embodiments of the invention. A simple illustration of a structure of a decontamination composition formed by the addition of a potassium chloride solution to sodium-montmorillonite clay is illustrated in FIG. 2. As illustrated, the potassium ions (K+) replace the sodium ions (Na+) in the interlayer of the montmorillonite clay and at some planar locations. In some instances, some sodium ions and other ions, such as calcium ions (Ca+), will also remain within the montmorillonite clay. In some embodiments of the invention, the solutions used to wet the decontamination compositions include potassium chloride solutions; however, various other salt solutions may also be used with embodiments of the present invention. For example, other solutions may include zinc (Zn) containing solutions, rubidium (Rb) containing solutions, and lithium (Li) containing solutions. Preferably, a solution selected for use with embodiments of the invention includes an ionic charge concentration of about 35 milliequivalents or less. In some embodiments, the solution is added to a clay composition in a four to one (4:1) ratio. In other embodiments, the solution is added to a clay composition in a ratio sufficient to expand the clay composition such that ion exchange and contamination capture may be achieved by the decontamination composition. Solutions used with embodiments of the invention may also include an acid or a base. Inclusion of an acid or base in a solution may optimize the decontamination process by providing improved decontamination effects against certain contaminants. For example, hydrochloric acid may be added to the solution to aid in the removal of contaminants from a material being decontaminated. The addition of an acid or a base may help to adapt the solution for the removal, or more effective removal, of a particular contaminant. Therefore, decontamination compositions according to embodiments of the invention may be customized to remove a selected contaminant based in part upon the composition of the solution used to form the decontamination composition. Furthermore, the addition of an acid or base to the solution may help to maintain the pH of the solutions used with embodiments of the invention. In some embodiments of the invention, it is preferred to maintain a pH of the solution between about 4 and about 7. In other embodiments, a pH of the solution is preferably between about 3 and about 9. As previously discussed, potassium chloride solutions may be used with embodiments of the present invention. For example, potassium chloride solutions added in a four to one (4:1) ratio to sodium-montmorillonite clays may be used with embodiments of the invention. Other ratios of solution to clay may also be used. The concentration of the potassium chloride solutions is preferably between about 15 mMol KCl and about 200 mMol KCl, although other concentrations may also be used with embodiments of the invention. For example, the concentration of potassium chloride solutions may be between about 15 mMol KC1 and 35 mMol KCl or between about 5 mMol KCl and about 50 mMol KCl. According to embodiments of the invention, a method for decontaminating a surface includes the application of a decontamination composition to the surface followed by removal of the decontamination composition a period of time later. Decontamination compositions according to embodiments of the invention may be applied in any manner, including, but not limited to, spraying, smearing, wiping, or otherwise applying the decontamination compositions to a surface or material. In other embodiments, the surface may be pretreated with a solution prior to the application of the decontamination composition to the surface. The solution used for pretreatment may include a solution used to wet the decontamination composition prior to application of the decontamination composition to the surface. According to still other embodiments, the surface may be treated with a decontamination treatment, such as a decontamination foam, which is removed prior to pre-pretreatment of the surface with a solution and the application of the decontamination composition. For instance, a decontamination composition formed from sodium-montmorillonite clay wetted by a potassium chloride solution may be applied to a contaminated surface to remove at least a portion of the contamination from the surface and sub-surface of the material. The application of a decontamination composition to a contaminated surface treats or decontaminates both the surface and the sub-surface of the material. Decontamination compositions according to embodiments of the invention are capable of removing contamination from a sub-surface and pores of a material or surface. When applied to a contaminated surface or material, decontamination compositions according to embodiments of the invention act in a similar manner to a poultice treatment, pulling contaminates off of the surface and out of the pores of the material. Application of the decontamination compositions to a surface also facilitates the diffusion of contaminants from a substrate or material to the surface of the material where the contaminants are sequestered by the decontamination composition. FIG. 3 provides a simple illustration of a montmorillonite decontamination composition wetted with a potassium chloride solution according to embodiments of the invention, which has been applied to a surface of a porous material. As illustrated, the potassium ions in the decontamination composition provide for an ion exchange with the porous material. The contaminate ions, represented by solid black circles, diffuse to the surface of the porous material where the decontamination composition acts as a zero-concentration boundary. The contaminate ions diffuse through the porous surface to the zero-concentration boundary where they are adsorbed or sequestered by the decontamination composition. The contaminant ions may be sequestered in the interlayer or at surface sites of the decontamination composition. The decontamination compositions according to embodiments of the invention may be applied to a surface in any thickness and in any manner. However, in some embodiments it is preferred to apply the decontamination compositions in a thickness of between about 0.5 centimeter to about 1 centimeter. In some embodiments of the invention, a contaminated surface is wetted with a solution, such as that used to form the decontamination compositions, prior to the application of the decontamination composition to the surface. Application of a solution to the surface prior to application of a decontamination composition of the present invention helps to promote ion exchange between the decontamination composition and the contaminated surface. In addition, the wetting of the contaminated surface with the solution prior to application of the decontamination composition may facilitate application of the decontamination composition to the surface. For example, in some instances a decontamination composition may adhere to a wetted surface better than to a non-wetted surface. Furthermore, application of a solution to a surface prior to application of a decontamination composition initiates a wetting of the surface and sub-surface of the contaminated surface. The wetting of the surface promotes the penetration of the solution into the pores of the surface and initiates ion exchange of contaminant ions from the sub-surface into a decontamination composition applied to the surface. According to other embodiments of the invention, a decontamination composition may be applied to a contaminated surface that has been previously treated to reduce the contamination on the surface or within the structure of the contaminated surface. For example, a decontamination foam as described in corresponding U.S. patent application Ser. No. 11/349,815 titled “LONG LASTING DECONTAMINATION FOAM,” filed on Feb. 7, 2006, now U.S. Pat. No. 7,846,888, issued Dec. 7, 2010, and incorporated herein by reference in its entirety, may be applied to a contaminated surface to remove an initial amount of contamination from the surface. Following removal of one or more applications of the decontamination foam, a decontamination composition of the present invention may be applied to the surface to further promote decontamination of the surface. As with other embodiments, the surface may be treated with a solution prior to application of the decontamination composition. The combined use of a decontamination foam for initial decontamination of the surface, followed by decontamination of the surface and sub-surface using a decontamination composition according to embodiments of the invention may provide improved decontamination of the contaminated surface or material. Once applied to a surface, decontamination compositions may also thereafter be treated or wetted with a solution. For example, a decontamination composition applied to a surface may begin to dry out due to evaporative losses. A solution, such as a salt solution, electrolyte solution, or a solution used to form the decontamination composition, may be applied to a decontamination composition that has been applied to a surface to help maintain the moisture content of the applied decontamination composition. Application of a solution to an applied decontamination composition may be by any of numerous methods, including, but not limited to, by spraying the solution on the composition, running a solution over the composition, attaching a sponge or other material, such as a wettable fabric or webbing, to the composition, coating the decontamination composition with a wax or other material to retain moisture in the composition, or by other known methods for wetting a surface. Once applied, a decontamination composition may be removed from a surface by any known methods. In some embodiments, the decontamination composition applied to a surface may be allowed to dry such that the decontamination composition readily falls away from a surface, may be easily chipped away, or otherwise mechanically removed. In other embodiments, the wetted decontamination composition may be removed and collected before drying. After removal, the decontamination compositions will exhibit levels of contamination based upon the amount of contamination removed from the contaminated surface. In order to contain the removed contamination, the decontamination compositions may be dried to reduce the size or volume of the now-contaminated decontamination composition and stored. In other embodiments, the contaminants removed from the surface by the decontamination composition may be recovered from the decontamination composition. The decontamination compositions according to embodiments of the present invention may be used to remove radioactive, bioactive, or chemical contaminants. For example, radioactive contaminants such as cobalt and cesium may be removed from a surface, material, or substrate using decontamination compositions according to embodiments of the invention. Other radioactive, bioactive, and chemical contaminants may also be removed. In general, decontamination compositions according to embodiments of the present invention may be applied to any surface or material to remove contamination. In many embodiments, the decontamination compositions may be applied to structural or building materials such as concrete, wood, marble, granite, glass and other materials. For example, structural materials exposed to radiation from a radiation leak or dirty bomb may be treated with decontamination compositions of the invention to remediate the contamination. Likewise, structural materials exposed to bioactive contaminants may also be treated according to embodiments of the invention. Various samples of decontamination compositions according to embodiments of the present invention were applied to contaminated surfaces that had been pretreated with decontamination foams such as those described in the aforementioned U.S. patent application titled “LONG LASTING DECONTAMINATION FOAM,” now U.S. Pat. No. 7,846,888, issued Dec. 7, 2010. The average decontamination achieved by the decontamination compositions on three particular surfaces—marble, granite, and concrete—is summarized in Examples 1 through 3. For each of Examples 1 through 3, the decontamination composition included SWY-2 sodium-montmorillonite clay from Wyoming, hydrated with a solution of 15 mMol potassium chloride (KCl) in deionized water. The ratio of solution to clay was four parts solution to one part clay (4:1) and the pH of the decontamination compositions was about 8. Once prepared and applied, each of the samples was placed into a plastic container with a tight sealing lid, along with some wet sponges. A marble surface contaminated with radioactive material was treated with two applications of a foam decontamination composition. The foam decontamination composition removed 72 percent of the contamination from the marble. A decontamination composition formed from sodium-montmorillonite according to embodiments of the present invention was then applied to the marble surface and was left on the surface for about a thirty-day period. Prior to application of the decontamination composition, a solution of 20 mMol potassium chloride (KCl) in deionized water was applied to the marble surface using a spray bottle. The treated surface was stored in a sealed container with some wet sponges during the thirty-day period. Following the thirty-day period, the decontamination composition was removed from the marble surface. Testing of the marble surface revealed that the decontamination composition further reduced the amount of contamination on the marble, from a total of 72 percent removal by the foam alone to 95 percent removal using the combination of the foam followed by the decontamination composition. Sampling of the contamination on the marble during testing was performed. Results illustrating removal of the radioactive contamination by the decontamination composition over time are illustrated in FIG. 4. A concrete surface contaminated with radioactive material was treated with two applications of a foam decontamination composition. The foam decontamination composition removed 29 percent of the contamination from the concrete. A decontamination composition formed from sodium-montmorillonite according to embodiments of the present invention was then applied to the concrete surface and was left on the surface for about a thirty-day period. Prior to application of the decontamination composition, a solution of 20 mMol potassium chloride (KCl) in deionized water was applied to the concrete surface using a spray bottle. The treated surface was stored in a sealed container with some wet sponges during the thirty-day period. Following the thirty-day period, the decontamination composition was removed from the concrete surface. Testing of the concrete surface revealed that the decontamination composition further reduced the amount of contamination on the concrete, from a total of 29 percent removal by the foam alone to 87 percent removal using the combination of the foam followed by the decontamination composition. Sampling of the contamination on the concrete during testing was performed. Results illustrating removal of the radioactive contamination by the decontamination composition over time are illustrated in FIG. 5. A radioactively contaminated granite surface was treated with two applications of a foam decontamination composition. A decontamination composition formed from sodium-montmorillonite according to embodiments of the present invention was then applied to the granite surface and was left on the surface for about a thirty-day period. Prior to application of the decontamination composition, a solution of 20 mMol potassium chloride (KCl) in deionized water was applied to the granite surface using a spray bottle. The treated surface was stored in a sealed container with some wet sponges during the thirty-day period. Following the thirty-day period, the decontamination composition was removed from the granite surface. Testing of the granite surface revealed that the decontamination composition further reduced the amount of contamination on the granite, from a total of 52 percent removal by the foam alone to 75 percent removal using the combination of the foam followed by the decontamination composition. Sampling of the contamination of the granite during testing was performed. Results illustrating removal of the radioactive contamination by the decontamination composition over time are illustrated in FIG. 6. Various fluids were also tested as hydrating solutions for the decontamination compositions according to embodiments of the present invention. The results achieved employing the various hydrating solutions with embodiments of the present invention are discussed below. The increases in contamination removal reflect increases over contamination removal using decontamination foams such as those described in the aforementioned U.S. patent application titled “LONG LASTING DECONTAMINATION FOAM,” now U.S. Pat. No. 7,846,888, issued Dec. 7, 2010. A decontamination composition according to embodiments of the invention was formed using a hydrating solution of 15 mMol potassium chloride (KCl). The ratio of hydrating solution to sodium-montmorillonite was four to one (4:1) and the pH of the decontamination composition was 7.9. Application of the decontamination composition to a contaminated surface resulted in an increase in decontamination of the surface by 17 percent over a one-day period. A decontamination composition according to embodiments of the invention was formed using a hydrating solution of 35 mMol potassium chloride (KCl). The ratio of hydrating solution to sodium-montmorillonite was four to one (4:1) and the pH of the decontamination composition was 7.9. Application of the decontamination composition to a contaminated surface resulted in an increase in decontamination of the surface by 40 percent over a four-day period. A decontamination composition according to embodiments of the invention was foil ied using a hydrating solution of 40 mMol potassium chloride (KCl). The ratio of hydrating solution to sodium-montmorillonite was four to one (4:1) and the pH of the decontamination composition was 7.9. Application of the decontamination composition to a contaminated surface resulted in an increase in decontamination of the surface by 15 percent over a four-day period. The decontamination composition formed according to this embodiment, however, lacked sufficient viscosity to remain intact and in position on a vertical surface. A decontamination composition according to embodiments of the invention was formed using a hydrating solution of 200 mMol potassium chloride (KCl). The ratio of hydrating solution to sodium-montmorillonite was three to two (3:2). Application of the decontamination composition to a contaminated surface resulted in an increase in decontamination of the surface by 35 percent over a four-day period. A decontamination composition according to embodiments of the invention was formed using a hydrating solution of 15 mMol zinc chloride (ZnCl2). The ratio of hydrating solution to sodium-montmorillonite was four to one (4:1) and the pH of the decontamination composition was 7.9. Application of the decontamination composition to contaminated concrete surfaces did not result in an increase in decontamination of the surfaces. An attempt to form a decontamination composition according to embodiments of the invention was made using a hydrating solution of 20 mMol zinc chloride (ZnCl2). The ratio of hydrating solution mixed with sodium-montmorillonite was four to one (4:1) and the pH of the decontamination composition was 7.9. Mixing of the hydrating solution and the sodium-montmorillonite failed to completely hydrate the sodium-montmorillonite clay. The resulting composition was a hydrating solution with sodium-montmorillonite clay flocculated out of the hydrating solution. A decontamination composition according to embodiments of the invention was formed using a hydrating solution of 0.01 Mol hydrochloric acid (HCl). The ratio of hydrating solution to sodium-montmorillonite was four to one (4:1) and the pH of the decontamination composition was 7.2. Application of the decontamination composition to contaminated concrete surfaces resulted in an increase in decontamination of the surfaces by 36 percent over a four-day period. A summary of the results obtained using these various hydrating solutions with embodiments of the invention are illustrated in Table II. TABLE IIRatio ofhydratingHydratingfluid toFluidclay (w/w)pHResult15 mMol 4:17.9After 1 day of treatment,KCldecontamination increased17 percent over base treatment35 mMol 4:17.9After 4 days of treatment,KCldecontamination increased40 percent over base treatment40 mMol4:17.9After 4 days of treatment,KCldecontamination increased 15 percentover base treatment. However, thesuspension lacked viscosity andwould not remain intact on avertical surface200 mMol3:2After 4 days of treatment,KCldecontamination increased35 percent over base treatment.15 mMol4:17.9No increase in decontaminationZnCl2over base treatment.20 mMol4:17.9The clay would not hydrate to formZnCl2a paste. It flocculated out of thehydrating solution.0.01M HCl4:17.2After 4 days of treatment,decontamination increased36 percent over base treatment. Having thus described certain currently preferred embodiments of the present invention, it is understood that the invention defined by the appended claims is not to be limited by particular details set forth in the above description, as many apparent variations thereof are contemplated without departing from the spirit or scope thereof as hereinafter claimed.
	summary
041347900	description	DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring first to FIG. 1, there is illustrated a typical nuclear reactor vessel 10 and reactor vessel closure head 12. The reactor vessel is typically vertically disposed in a concrete reactor cavity 13 and connected to other components of the nuclear steam supply system (not shown) by means of a reactor coolant inlet nozzle 14 and outlet nozzle 16. Most of the components internal to the reactor vessel 10 are supported directly or indirectly by the core support barrel 18 which is suspended from and firmly engaged between the closure surface between the vessel head 12 and the top of the reactor vessel 10. The core support assembly 20 rests on the bottom of the core support barrel 18 and the core support plate 22 rests on top of the core support assembly 20. The core support plate 22 serves to support and align a plurality of fuel assemblies 24 which are also aligned at the top by the upper core alignment plate 26. Alignment of the assemblies 24 at the top and bottom is typically effected by means of fuel assembly end fittings (not shown) which are adapted to mate with end fitting receiving means (not shown) on the core support plate 22 and the upper core alignment plate 26. During normal reactor operation, a liquid coolant enters the vessel through inlet nozzle 14 and follows the flow path 32 down the outside of the core support barrel 18 and up through the core support assembly 20 which structures are adequately orificed for such flow. The coolant continues upward through the fuel assemblies 24 where mixing grids (not shown) and thousands of individual fuel rods (not shown) produce large flow resistances tending to push the fuel assemblies 24 towards the upper core alignment plate 26. The alignment plate 26 is typically restrained from moving upwards by the downward force of the upper guide structure support plate 30 transmitted through a plurality of control rod shroud tubes 28 welded to the upper guide structure support plate 30 and the upper core alignment plate 26. The upper guide structure support plate 30 is suspended from and firmly engaged between the closure surface of the vessel head 12 and top of the reactor vessel 10. The upper core alignment plate 26 is orificed to permit coolant to enter the region of the control rod shroud tubes 28, but the upper guide structure support plate 30 is essentially integral so that the coolant flow continues on the flow path 32 through the outlet nozzle 16. Each control rod, only one of which 29 is shown, must have a clear path for insertion and withdrawal over the entire vertical extent of the fuel assemblies 24. This is accomplished by providing control rod shroud tubes 28 connected with control rod guide tubes (not shown) in the fuel assemblies 24. Referring now to FIGS. 2 and 4, a typical fuel assembly 31 includes five vertically extending zircaloy control rod guide tubes 38 to which are welded stainless steel upper and lower end fittings 34 and 44, respectively, and a plurality of axially disposed rectangular fuel spacer grids 42. These grids maintain the lateral spacing of the plurality of nuclear fuel rods 40 while permitting a limited amount of axial motion resulting from fuel rod expansion. Each fuel rod is welded at its bottom to the top of the fuel assembly lower end fitting 44. The bottom of each guide tube 38 is also welded to the top of the lower end fitting 44. Four vertically extending and equally spaced fuel assembly alignment posts 46 are welded to the bottom of the fuel assembly lower end fitting 44 and support the entire weight of the fuel assembly against the core support plate 22. Fuel assembly alignment pins 52 extend upward from the core support plate 22 and are located in a uniform array on the core support plate such that each alignment pin 52 can be slidably received by the fuel assembly alignment post 46 on one corner of each of four fuel assemblies 31 properly located on the core support plate 22. When the fuel assembly alignment posts 46 are properly positioned on the core support plate 22, the latch 56 on the cantilever leaf spring 48 attached to the fuel assembly alignment post 46 with attachment means 50 engages a recessed region 54 in the fuel alignment pin 52. When it is desired that the fuel assembly be removed from the core or relocated, the usual steps of unbolting and removing the reactor vessel head 12 and lifting the upper guide structure support plate 30 are followed. As described above, the control rod shroud tubes 28 are welded to the upper core alignment plate 26 and to the upper guide structure support plate 30 so that when the support plate 30 is lifted from the reactor the alignment plate 26 is also removed, exposing the upper end fittings 34 of all the fuel assemblies 24. To remove a fuel assembly from the core, the assembly is grasped at the upper end fitting 34 by the grappling tool on the refueling machine, which is customarily provided in all reactor installations. An upward force of about 3,000 pounds is required to overcome the hold-down force between the latch 56 and the recessed region 54 and to lift the fuel assembly out of the reactor. This force is well within the capabilities of a typical refueling machine. A new or relocated fuel assembly can now be inserted in the location vacated by the removed assembly. The refueling machine lowers the new assembly into position between the four corner fuel alignment pins 52. The latch 56 of each cantilever spring 48 in its relaxed position will contact the upper portion of the fuel alignment pin 52. As the assembly continues to be lowered, each spring 48 will be deflectively loaded by the weight of the fuel assembly. As the fuel assembly alignment posts 46 contact the core support plate 22, each spring latch 56 snaps into engagement with the recessed region 54 on the fuel alignment pin 52. The grappling tool on the refueling machine is then released and withdrawn from the reactor. After all assemblies have been placed in their proper positions, the upper core alignment plate 26 is repositioned over the fuel assembly upper end fittings 34. Proper alignment of the fuel assembly is maintained by the sliding engagement of the upper fuel assembly alignment pins 36 into the recesses 37 in the upper core alignment plate. These recesses are large enough to accommodate the axial expansion of the control rod guide tubes 38 during core operation. The upper core alignment plate 26 is then firmly held in place when the vessel head 12 is tightened down. In the preferred embodiment, only two non-diagonal fuel assembly alignment posts of the four in any given assembly are fitted with the cantilever spring 48. When the assembly is in place on the core support plate 22 and each latch 56 is engaged in the recessed region 54 associated with these two non-diagonal posts, the horizontal component of the loaded spring force is sufficient to produce a very tight contact between the other two non-diagonal alignment posts 46' and associated alignment pins 52'. The net outwardly directed horizontal forces against the four fuel alignment pins 52 and 52' associated with a given fuel assembly are sufficient to preclude significant lateral motion of the assembly during core operation. The relationship of the fuel assembly alignment posts 46 to the fuel alignment pins 52 is more fully illustrated in FIG. 3. The square fuel assembly lower end fitting 44 has a ribbed internal structure 45 to permit upward flow of coolant through the assembly and has the five control rod guide tubes 38 welded in a symetric pattern with the bottom end open to receive the coolant flow. A fuel assembly alignment post 46 is welded to the bottom of the lower end fitting 44 near each corner. The shape of the fuel assembly alignment post 46 is designed to slidably engage the fuel alignment pin 52, one of which is shared by four assemblies. Cantilever springs 48 are attached to two non-diagonal alignment posts 46 through bolt means 50. The other two non-diagonal alignment posts 46' are held firmly against alignment pins 52' by the horizontal force component of the cantilever springs as described above. Referring now to FIG. 4, the fuel assembly alignment pin 52 has an upper cylindrical portion connected to a lower cylindrical portion of smaller diameter by a recessed region 54 having a downwardly inclined annular surface at an angle of approximately 30.degree. with the horizontal. The alignment pin 52 is permanently and rigidly attached to the core support plate 22. The fuel assembly alignment post 46 is shown in the proper position whereby the fuel assembly will be held down during core operation. The alignment post 46 extends vertically in parallel with and in close proximity to the upper portion of the alignment pin 52. A cantilever leaf spring 48 is attached to the upper portion of the fuel assembly alignment post 46 by bolt means 50 and extends downward along the side of alignment post 46 that faces away from alignment pin 52. At an elevation above the core support plate 22 slightly above the elevation of the recessed region of the alignment pin 54, the alignment post 46 has a cut-out passageway 47 extending downward far enough to permit the cantilever leaf spring latch 56 to protrude above the side of the alignment post 46 that faces alignment pin 52. The latch 56 has an inclined surface 58 which makes an angle with the horizontal substantially the same as the angle of the recessed region 54. In the locked position illustrated in FIG. 4, the cantilever spring 48 has a loaded deflection of about 0.089 inches, resulting in a horizontal force of about 450 pounds applied to the inclined surface 58. The vertical load on spring 48 required to disengage latch 56 is approximately 4,180 pounds. The maximum deflection of the cantilever spring 48 occurs during insertion and removal of the fuel assembly when the latch 56 is in contact with the upper portion of the fuel alignment pin 52, resulting in a total spring deflection of 0.189 inches. These dimensions are representative of a typical application wherein the fuel assembly lower end fitting is approximately 8.2 inches square and the length of the fuel assembly alignment post is approximately 5 inches. The spring 48 can be designed to either lock and force the alignment posts 46 down against the core support plate 22, or a slight gap may be permitted to exist during core operation. In this case the fuel assembly 30 would lift until the latch 56 contacts the recessed region 54. Because the springs provide a vertical friction force there results a certain amount of hysterisis which prevents vertical chatter. Referring now to FIG. 5, an alternate embodiment of the invention is shown wherein the cantilever leaf spring 48 is attached to the side of the fuel assembly alignment post 46 that faces the alignment pin 52. As shown in FIG. 6, another embodiment of the invention includes a horizontally disposed coil spring 60 for augmenting the force of the cantilever spring 48 on latch 56. It is contemplated that a person of ordinary skill in this art could adjust the length or material of cantilever spring 48 or the angles on the inclined surfaces 58 and 54 to achieve the desired combination of vertical hold-down forces and horizontal stabilizing forces between the latch, pins, and posts. In the preferred embodiment each latch provides both vertical and horizontal force components. The desired horizontal force, however, should not be so large as to require more downward force for actuating the locking mechanism than is provided by the weight of the fuel assembly itself, since any additional force would result in an undesirable compression of the control rod guide tubes 38. Furthermore, the present invention is not limited to the use of cylindrical alignment pins 52 or any particular shape of fuel assembly alignment post 46. For example, the alignment posts 46 can be adapted to perimetrically surround the alignment pins 52. It is further contemplated that a person of ordinary skill in this art could practice the invention by attaching the spring to the alignment pin to mate with a recessed region on the alignment post.
	abstract	A filter system for filtering debris particles out of a predetermined cross-section of the radiation emitted by a radiation source of a lithographic apparatus includes a first set of foils and a second set of foils for trapping the debris particles, and a first heat sink and a second heat sink. Each foil of the first set is thermally connected to the first heat sink, and each foil of the second set is thermally connected to the second heat sink, so that heat is conducted substantially towards the first heat sink through each foil of the first set, and heat is conducted substantially towards the second heat sink through each foil of the second set. The first set extend substantially in a first section of the predetermined cross-section, and the second set extend substantially in a second section of the predetermined cross-section. The first and second sections are substantially non-overlapping.
047708417	description	DETAILED DESCRIPTION The present invention relates to an apparatus for the control of dynamic systems. The methods and apparatus of the present invention are generally applicable to all systems. For example, it may be applied to process plants, process simulators, or electronic systems. Dynamical systems can be generally represented by a set of differential equations of the form ##EQU2## where x(t) is an n-vector function of time completely specifying the condition of the plant, A is an n by n state transition matrix, v(t) is an m-vector input function of time and B is an n by n distribution matrix. Results which are produced by the system are generally known as outputs of the system. These outputs generally fall into two classifications, measurable outputs and unmeasurable outputs. Measurable outputs generally include the physical manifestations of the system, such as flow rate or signal voltage, while the non-measurable outputs generally include noise produced by the system. The measurable outputs of the system are generally related to the state variables of the systems according to the following equation EQU y(t)=Cx(t) (2) where y(t) is an r-vector function of time representative of the measurable outputs of the system and C is an r by n output matrix. Dynamic systems are generally controlled by manipulation of one or more of the components which make up the inputs v(t) of the system in order to control at least one of the components which make up the outputs y(t) of the system. The operation of observer blocks and the observer theory upon which they are based are well known in the art and will not be discussed in the present specification in detail. For a detailed discussion of observer theory see "Optimum Systems Control", 2nd Prentic Hall (1977), by Andrew P. Sage and Chelsea C. White III, which is incorporated herein by reference. According to the methods of the present invention, an observer block is used to act on the vector time functions v(t) and y(t) to reconstruct an estimate, x(t), of the plant states x(t). In order to aid in the understanding of the present invention, a brief outline of observer theory is provided. The observer is a dynamical system governed by the differential equation, ##EQU3## where z(t) is an s-vector function of time, F is an s by s state transition matrix, L is an s by r distribution matrix, and T is an r by n matrix which satisfies the following matrix equation: EQU TA-FT=LC (4) with EQU r+s=n (5) Selection of L and F which define the observer are treated in modern control theory literature on observer design and therefore are not examined in detail in the present specification. Standard procedures also exist for the solution of Equation 4 when F is in Jordan canonical form. According to observer theory, the following equation holds: EQU x(t)+Ry(t)+Sz(t)=x(t)+e.sub.x (t) (6) where R is an n by r matrix taken from the first r columns of the n by n matrix M, where ##EQU4## and where S is an n by s matrix taken from the last s columns of M. The error term behaves as EQU e.sub.x (t)=S.multidot.e.sup.Ft .multidot.z.sub.E (o) (8) where e.sup.Ft is the matrix exponential function and EQU z.sub.E (0)=z(0)-Tx(0) (9) is the initial error in the observer states. Since F is always chosen to have left-half plan eigenvalues, e.sub.x (t) approaches zero as the system runs in time. Equations 3 through 9 are well known in the literature and thus the design of an observer to obtain the estimated states x(t) is well known. Referring now to FIG. 1, a description of a control system according to the methods and apparatus of the present invention will now be described. It is known that every system, whether it be process, electrical, or otherwise, is governed over time according to the internal dynamics of the system. In the illustration shown in FIG. 1, these dynamics are represented schematically by block 101. The system inputs 103 act through the system dynamics to effect changes in the system outputs 102. The exact quality and quantity of these changes for any given change in system inputs is determined by the system dynamics 101. It will be appreciated by those skilled in the art that systems having complex dynamics will always have at least one output and will generally have at least two inputs. Included in the system inputs for most complex dynamic systems are at least one load variable 104 and at least one manipulated variable 105. The load variable will generally be independent of the particular control system under investigation. The manipulated variable 105 is controlled by the control system in order to affect the system output 102 in a predetermined fashion. In many systems, such as some electrical systems for example, the system inputs and system outputs are feed directly to the observer block of the present invention as shown at 102A and 103A. In other systems, such as chemical process systems and nuclear steam supply systems, system inputs and system outputs are coupled to measuring means represented schematically by block 106. The measuring means then generate signals 102M and 103M representative of the measured values for the system inputs and system outputs respectively. The observer block 107 receives the system inputs and outputs or the signals representative thereof. Based upon these inputs and outputs, the observer block 107 then generates estimates, x(t), of the state variables of the system. It should be noted that as long as the measured inputs 103M and the measured outputs 102M closely approximate the actual inputs 102A and the actual outputs 103A, the state variable estimates 108 generated by observer block 107 will be very close approximations of the state variables of the system. The state variables thus estimated are sent to the predictor block 109. The predictor block 109 uses a linear combination of the state variable estimates to generate a compensated output y.sub.c (t), labelled as 110 in FIG. 1. An important feature of the present invention resides in the properties of the compensated output. More particularly, the transfer function between the manipulated variable 105 and the compensated output 110 has no right half plane zeroes. As the term is used herein, a right half plane zero is a root of the numerator of a transfer function, wherein the root is located to the right of the imaginary axis in the complex plane. According to a preferred embodiment of the present invention, this transfer function also does not have any time delay. The compensated output y.sub.c (t) is thus generated according to the methods of the present invention such that it represents the steady state asymptote of the system output 102. The dynamic relationship between the system inputs and the system outputs can generally be described according to the following equation EQU Y(s)=H.sub.u (s).multidot.U(s).+-.H.sub.w (s).multidot.W(s) (10) where Y(s) is the Laplace transform of the system output, U(s) is the Laplace transform of the manipulated variable, and W(s) is the Laplace transform of the load variable. H.sub.u (s) and H.sub.w (s) are the transfer functions relating their respective inputs to the outputs. The transfer function for the manipulated variable can generally be written according to the following partial fraction expansion, ##EQU5## where m.sub.i is the multiplicity of roots .sub.i and m.sub.T is such that if the system order is n then ##EQU6## A compensated transfer function according to the present invention may then be defined by first defining a subset S.sub.1 of the natural modes of the manipulated variable transfer function H.sub.u (s). As the term is used herein, a mode is a pole or root of the transfer function. As the term is used herein, a pole or root of a transfer function is a root of the denominator of the transfer function. More particularly, a pole or root is a value of s of the transfer function for which the value of the transfer function approaches infinity. An integration mode is a pole or root having a value of s equal to zero. Included in the subset S.sub.1 are those poles or roots of H.sub.u (s) for which: (1) the real part of .lambda..sub.i is greater than or equal to zero; or (2) .lambda..sub.i represents a dominant mode of H.sub.u (s) near no zeroes of H.sub.u (s). The first condition assures that all unstable modes and integration modes of the manipulated variable transfer function are controlled while the second condition permits modification of the behavior of any dominant stable modes. While the subset S.sub.1 should contain at least those modes described above, other modes of the manipulated variable transfer function can be included in the compensated transfer function. With the subset S.sub.1 thus defined, several techniques are available for defining the compensated transfer function according to the present invention. For the purposes of illustration, such techniques will be discussed below. The compensated transfer function, H.sub.c (s), of the present invention may be defined according to an equation having the following form ##EQU7## with the constant k.sub.1 chosen such that ##EQU8## Equation 13 ensures that H.sub.c (s) has no right half plane zeros and includes all modes that need to be stabilized or speeded up in their responses. Equation 14 ensures that H.sub.c (s) has the proper asymptotic behavior near S=0. Another method for defining H.sub.c (s) is to utilize the following equation ##EQU9## With the compensated transfer function in the form of equation 15 it is necessary to ensure that H.sub.c (s) has no right half plane zeros. If this is found to be true, then this definition of H.sub.c (s) is appropriate for the present invention. It will be appreciated that other methods for generating compensated transfer functions are available. For example, the right hand side of equation 13 may, in general, may be multiplied by a polynominal having only left half plane zeros. This multiplication will result in a compensated transfer function having the properties described above. Since the observer block gives an estimate of all the state variables of the system, a linear combination of the state variable estimates x.sub.i (t) can be related to the transform of the manipulated variable U(s) according to the following equation EQU X.sub.i (s)=G.sub.i (s).multidot.U(s) (16) where X.sub.i (s) is a transform of the state variable estimate, and G.sub.i (s) is the transfer function relating U(s) to X.sub.i (s). An important feature of the present invention resides in establishing an identity between the compensated transfer function H.sub.c (s) and the observer based transfer function G.sub.i (s). More particularly, the applicant has found that the following identity can be established ##EQU10## where c.sub.i are those uniquely determined constants which satisfy the above identity. Techniques such as advanced linear algebraical manipulation are available for determining the set of c.sub.i which satisfy the identity of equation 17. With the uniquely determined set of constants c.sub.i thus established, the compensated system output is determined according to the following equation ##EQU11## where c.sub.i are determined by the identity disclosed in equation 17, the estimated plant states are determined by the observer block 107 and K.sub.2 is chosen so as to ensure that the compensated output has the same value as the actual output when the system is at steady state. In systems having time delays represented by e.sup.-sT for the transfer function of the manipulated variable H.sub.u (s), the time delays can be approximated by a rational transfer function expansion that accurately represents e.sup.-sT up to an appropriately chosen cutoff frequency. These techniques are known in the art and are not described in detail in the present specification. By using such methods to approximate the time delay, the previously described methods for generating the compensated output can be applied to systems having time delay. By eliminating both time delay and right half plane zero behavior from the compensated output, the present invention provides a compensated output variable y.sub.c (t) which is very simple to control. Moreover, the control of y.sub.c (t) to a steady state value brings the actual system output to the same steady state value. According to one embodiment of the present invention, the system outputs 102 are controlled by controlling the compensated output 110. More particularly, referring again to FIG. 1, the value of y.sub.c (t) is compared in automatic controller 112 to a set point 111. Based upon the difference or error between set point 111 and compensated output 110, the controller 112 will make adjustments to the manipulated value 105 so as to minimize error between the compensated output and the set point. Since the system output 102 will asymptotically approach the compensated 110 under steady state conditions, control of the compensated output 110 provides for effective and stable control of the system outputs 102 even when the system dynamics 101 contain right half planes zeros or time delay. Another important feature of the predictor block 109 of the present invention is the inclusion therein of means for predicting the bounded outputs Y.sub.b (t), labelled as 113 in FIG. 1. Thus, predictor 109 provides an accurate estimate of the maximum or minimum excursion of the system outputs 102 for fixed values of the load variable and the manipulated variable. Even though the compensated output defined according to the techniques described above has no right half plane zeroes, the system output always retains any right half plane zero behavior regardless of how one chooses to manipulate the variable 105. Thus, it is desirable to prevent the system from crossing limits that the system output 102 may otherwise reach in its trajectory to the steady state as predicted by the compensated output 110. The bounded output Y.sub.b (t) represents that maximum and/or minimum excursions of the system outputs 102 for a constant load variable and either constant manipulated variable or a constant linear feedback law governing the manipulated variable. The method of predicting the bounded output includes solving the following equation for all values of t in the future ##EQU12## The solution to the above equation is then used to find the extrema of the trajectory for the plant outputs. The steady state solution of equation 1, subject to v(t)=v.sub.0, is EQU x(t)=e.sup.At x(0)+A.sup.-1 [e.sup.At -I]Bv.sub.o (20) where I is the n by n identity matrix and x(0) is the state at t=0. The expression A.sup.-1 [e.sup.At -I] can be expanded in terms of normal modes. Hence, one finds such that ##EQU13## The values of t thus derived are used to compute the extrema of the system outputs. If the manipulated variable is implemented by linear control law such that u(t).ltoreq.-k(x(t)-x.sub.o) where k feedback matrix and x.sub.o is the steady state solution corresponding to u=w=w.sub.o, the bounded output can be solved by modifying the A matrix of equation 20 as follows EQU A'=A=kb.sub.u (22) where b.sub.u is the column of B multiplying u(t) in equation 1. This value of A' can then be used in equations 20 and 21 to compute the extrema. Thus, the extrema can be predicted according to the present invention under constant control for the unit operator or under linear feedback for the automatic controller. According to another embodiment of the present invention, the compensated output 110 and bounded output 113 may be made available to the human operator by means of the operator display 114 in order to improve the performance of either an automatic controller or a human operator. In the case of a human operator, his/her performance can be improved in a number of ways. For example, the compensated output and bounded output can be displayed along with other selected inputs and outputs during actual system operation. In other applications, this same information can be used as training devices to provide an operator with concrete experience with the non-intuitive dynamics of non-minimum phase systems. Effective prediction and control is based, in part, on the controller having a good internal model of the dynamics of the process under control. A human controller develops his/her internal model and predictive capability through experience with the control task. The present invention can provide the human operator with improved visualization of the system or process dynamics and can increase the effectiveness of training time on the control task. In either case, it is preferred that the information generated according to the present invention be presented graphically to the operator or trainee during control of the actual or simulated system. There are several ways to deploy the predictive information generated according to the methods of the present invention. For example, a trend plot of the compensated output can be presented parallel with or along side a trend plot of the actual plant output for the particular system in question. This allows visual comparison of the two curves and enables the human controller to distinguish steady state changes from transient effects on system output. That is, for example, the human controller will be able to visualize the shrink/swell effects described above and will be able to distinguish them from non transient behavior of the system. Due to the properties of the compensated output described above, the actual system outputs will approach the compensated outputs as the transient effect of the system dynamics die away with time. More particularly, since at any point in time the compensated output represents the ultimate steady state value of the system outputs, the difference between the compensated output 110 and the actual system output 102 at any moment in time provides information about the future behavior of the system output. According to another preferred embodiment of the present invention the bounded output 113 may be displayed to the human operator as an aid in control of the system in question. That is, the methods of the present invention allow either the human operator or the automatic controller to receive information on the minimum/maximum excursion that will result in the actual system outputs 102 due to a current change in a system input 103. Thus an operator can see at a glance the maximum or minimum excursion that will occur in the system outputs 102 as its completes its trajectory to the steady state value predicted by the compensated output 110. If the value of the bound output indicates this excursion will exceed some predefined limits in the system output, the human operator can take corrective action and instaneously see the results that this action will have on both the bounded output and compensated output. For example, if the bounded output is near a limit value for the system, the controller, whether it be automatic or human, can adjust the rate of change of the system output 103 to bring it on target more slowly. It will be appreciated by those skilled in the art that other techniques are available for the use and display of the compensated output and bounded output generated by the present invention. For example, the bounded output could be deployed as a dynamic limit on the rate of change in the manipulated variable 105. This limit could be calculated on the difference between the compensated output and the system output relative to the target value and on the differences between the minimum/maximum value and a low/high limit values. According a preferred embodiment of the present invention, observor block 107 and predictor 109 are electronic circuit means which perform functions described above. In another preferred embodiment, said circuit means comprises a microprocessor having computational and memory capacity. The observor block 107 and the predictor 109 are appropriately coupled such that the state variable estimates generated by the observor block are received by the predictor. In a preferred embodiment of the present invention, operator display 114 comprises a cathode ray tube display and software associated therewith for graphically illustrating the actual system inputs 103, the actual system outputs 102, the compensated output 110, and the bounded output 113. In other embodiments, it may be desirable to provide said cathode ray tube display with multicolored display means. Automatic controller 110 can be any automatic controller capable of accepting and acting upon inputs 111, 110 and 113. For the purposes of illustration and not by way of limitation, a relatively simple example of the use of the present invention in a nuclear reactor steam system is presented below. Referring now to FIG. 2, a schematic view of the nuclear reactor steam supply system coupled to one embodiment of the present invention is disclosed. The steam generator vessel 200 is supplied with feedwater through inlet manifold 201. The steam thus generated exits through steam manifold 202. A level control element 203 provides an indication of the feedwater level in the steam generator 200. The rate of steam flow from manifold 202 is determined by the position of valve 204 while the rate of feedwater flow into the generator 200 is determined by the position of valve 205. The heat input to the steam generator 200 is determined by the flow and temperature of process water passing through a manifold 206, which is in turn determined by the energy released by the nuclear reactor 207. Measuring elements 208 and 209 measure the pertinent properties of the feedwater and steam flow respectively. More particularly, measuring element 208 determines the rate of the steam flowing through manifold 202 while element 209 measure the rate of the feedwater entering generator 200. In the context of the present example, steam generator 200 represents the system dynamics, the level of the feedwater indicated by level indicator 203 is the output of the system, and the feedwater flow and the steam flow represent inputs to the system. More particularly, in the control scheme revealed in FIG. 2, feedwater flow comprises the manipulated variable while the steam flow comprises the load variable. Thus, the feedwater level, the feedwater flow, and the steam flow are sent to the observer block 107 and are represented by the symbols y(t), u(t) and w(t) respectively. The observer block 107 acts upon these system inputs and the system output and generates an estimate of the state variable x.sub.i (t). In order to more clearly understand the system shown schematically in FIG. 2, a more detailed block diagram of the system dynamics of steam generator 200 and the dynamics of the observer block 107 to which it is coupled is shown in FIG. 3. In this simple system, the plant dynamics 101 are represented by the following nonminimum phase transfer functions ##EQU14## where H.sub.u (s) is the transfer function for the feedwater flow, H(s) is the transfer function for the steam flow, and T.sub.0 and T.sub.3 are contants particular to the system. These transfer functions have normal roots at s=0 and s=-1/T.sub.1. The right half plane zero at s=1/T.sub.2 makes this system difficult to control from feedwater flow u(t). If should be noted that the feedwater flow u(t) is shown as passing into both the system dynamics and the observer dynamics without first passing through a measuring means. In a system of the type discussed in this example, this is a very close approximation of actual conditions since feedwater flow is generally very acurately known. On the other hand, FIG. 3 indicates that the steam flow, while feeding directly into the plant dynamics, is joined with an error term e(t) which represents the error introduced into the measured steam flow by measuring means 208. The system dynamics 101 operate on the system inputs, i.e., steam flow and feedwater flow, to produce the system output, i.e., feedwater level Y(t). These inputs and the output are then transferred to the observer block 107, the dynamics of which are shown in FIG. 3. The observer has a single root s=-1/T.sub.4. Based upon the Laplace transforms of equations 3 and 6 described above and an observer driven by a plant having the dynamics shown in FIG. 3, the observer dynamics indicated in FIG. 3 are derived. The observer is specified by the four constant coefficients shown in FIG. 3. The observer operates on the plant inputs and output and generates an estimate of the state variables. The two estimates of the state variables in normal form are shown as x.sub.1 (t) and x.sub.2 (t). Of the system dynamics shown in FIG. 3, the compensated transfer function shown below results from either of the methods described above: ##EQU15## This form of H.sub.c (s) results since the transfer functions for the inputs have no unstable poles and have only a single integration pole at s=0. For the purposes of convenience and illustration, but not by way of limitation, it is desirable to assume that u(t)=w(t)=w.sub.0, where w.sub.0 is an equilibrium point for some range of w(t) and thus, H.sub.w (s) and H.sub.u (s) will have different residues only for the stable modes of the transfer functions. Based upon this assumption, K.sub.2 can be determined as follows so as to ensure that the steady state value of actual feedwater level is ultimately identical to the compensated feedwater level value. ##EQU16## Satisfying the identity of equation 18, the compensated level is thus generated as follows ##EQU17## The generation of the bounded output y.sub.o (t) is as follows. ##EQU18## Thus with an explicit solution for y(t+.DELTA.t) one can easily differentiate equation 28 to find .DELTA.t for which ##EQU19## Solving for the exponential term one gets ##EQU20## as the condition for the time at which an extrema occurs. For this plant, four possibilities exist 1. u=w so that v=0 and equation 34 has no solution. In this case EQU y.sub.b (t)=y.sub.c (t) (35a) PA0 2. The term on the right is negative and again equation 34 has no solution. This is the case where the derivative of y(t) does not change sign. Again EQU y.sub.b (t)=y.sub.c (t) (35b) PA0 3. A solution exists to equation 34 but .DELTA.t is negative. In this case the present time is past the point at which the trajectory of y(t+.DELTA.t) goes through an extrema. Again EQU y.sub.b (t)=y.sub.c (t) (35c) PA0 4. A solution exists to equation 34 and .DELTA.t is nonnegative. In this case one substitutes this value of .DELTA.t in equations 29 and 30, then evaluates Equation 28 to find ##EQU21## The function yb(t) is continuously evaluated as a function of the state estimates x.sub.1 (t), x.sub.2 (t), the steam flow w(t) and the feedwater flow u(t). If u(t) and w(t) are held constant and equation 35d applies, y.sub.b (t) remains constant as a function of time until the maximum/minimum is reached. After the trajectory y(t) either peaks or bottoms out y.sub.b (t) jumps discontinuously to the value of y.sub.c (t). Referring now to FIG. 4, one method of displaying the predictive information generated according to the present invention in order to aid the human operator in the control of a nuclear steam supply system is disclosed. The abscissa of this graph represents time where t=0 is the present; points to the left of t=0 represent the past; and points to the right of t=0 represent the future. The ordinant of this graph, for the purposes of convenience, represents the percent of scale for each of the variables shown in the graph. The system output, in this case feedwater level y(t) is displayed concurrently with the compensated output y.sub.c (t). Changes in the manipulated variable, in this case feedwater flow u(t) are also shown. It should be noted that the graphs in FIG. 4 qualitatively represent the response of the systems dynamics shown in FIG. 2 in the situation in which no control action is implemented. Thus it is seen that the dynamics of the steam supply system are such that a step change reduction in the feedwater flow u(t) results initially in a gradual increase in the actual feedwater level Y(t). It will be appreciated by one skilled in the art that classical or standard control systems will provide the automatic controller 112 with a very low gain in order to prevent substantial improper manipulation of the feedwater flow. This very low gain in turn will result in a control system which achieves target output only after a very long time. In contrast, the control system according to the present invention will manipulate the feedwater flow according to the value represented by the compensated output y.sub.c (t). More particularly, since the compensated output represents the steady state value which will ultimately be reached by the actual output if u(t) is returned to its equilibrium value, the proper control action can be immediately take when such action is based upon the difference between the compensated output and the set point. As a result, the control system of the present invention responds much more quickly and in such a manner so as to avoid the production of unstable responses. According to a preferred embodiment of the present invention, the bounded output y.sub.b (t) is also displayed to the operator as indicated in FIG. 4. This display will allow the operator to determine at a glance the maximum excursion of the actual feedwater level Y(t) for any change in u(t) and compare these maximum and minimum to the allowed limits for the system. More particularly, an operator can set a value for the feedwater flow u(t) and immediately see what the extremes of the trajectory (if any) will be. If the predicted extrema exceed permissible values the operator can readjust the value of feedwater so that the limits on feedwater level are not exceeded while simultaneously minimizing the time required for the actual feedwater level Y(t) to return to its desired setpoint value after an initial disturbance. It will be appreciated by those skilled in the art the present invention has uses and advantages which provide a substantial improvement over control systems heretofore known. For example, apparatus and methods of the present control system mitigate the inherent difficulty of controlling non-minimum phase systems. That is, substitution of compensated system output having no time delay or right half plane zero behavior for the actual system output results in a system which is simply and stably controlled. Oscillation, over control and unstable control are avoided. Moreover, the present invention is applicable to systems with unstable modes or pure integration modes in their dynamic description. The problem of drift associated with using a model with an integrator to simulate the plant having integration is avoided. In effect, the observer block 107 relies upon the system itself to perform the integration and thus avoids the need for an integration mode in the observer. In addition, the compensated output provides predictive information that has heretofore been unavailable to either human operators or automatic controllers. Other advantages and uses of the present invention are also possible. For example, parametric studies can be performed on a simulated plant to determine required modelling accuracies. That is, errors may be deliberately introduced to degrade the observer design in order to study the sensitivity of the operator to both the magnitude and sign of the error. In addition, it can be determined whether the estimates of the model parameters may be biased so that the compensated plant output differs from the actual output in a conservative way.
	claims	1. A boiling water reactor comprising:a reactor pressure vessel that includes a main body trunk having an upper open end and an openable upper lid covering the upper open end of the main body trunk from above;a reactor vessel vent line that penetrates lateral side of the main body trunk and has an opening section at a same level with or higher than the upper open end of the main body trunk in the reactor pressure vessel;a containment vessel that includes a dry well for containing the reactor pressure vessel;a sump arranged in the dry well and outside the reactor pressure vessel;a condensation tank arranged in the dry well and outside the reactor pressure vessel;a water level gauge arranged below the condensation tank in the dry well and outside the reactor pressure vessel;a nitrogen gas filling line branched from a gas phase piping;a water piping which extends downward from the condensation tank via the water level gauge and is connected to the main body at a position lower than the water level gauge, whereinthe reactor vessel vent line includes a gas phase piping extending substantially horizontally penetrating the main body trunk and connected to the condensation tank, and a sump connecting piping that is connected to the sump. 2. The boiling water reactor according to claim 1, wherein the containment vessel further includes a wet well having a suppression pool and communicating with the dry well. 3. The boiling water reactor according to claim 2, whereinthe reactor vessel vent line is connected to the suppression pool. 4. The boiling water reactor according to claim 1, whereinthe reactor vessel vent line is connected to a head spray line for supplying spray water for cooling the upper lid from inside into the reactor pressure vessel. 5. The boiling water reactor according to claim 4, whereinthe head spray line is so arranged as to directly spray water to the inner surface of the upper lid. 6. The boiling water reactor according to claim 4, whereinthe main body trunk and the upper lid are coupled together at a junction that has a flange structure such that a main body trunk flange and an upper lid flange are coupled together, andthe head spray line is so arranged as to directly spray water to inner surface of the main body trunk flange and inner surface of the upper lid flange. 7. The boiling water reactor according to claim 4, whereinthe head spray line is so arranged that the spray water is partly jetted out upwardly in the reactor pressure vessel.
	abstract	For use in charged-particle-beam (CPB) microlithography apparatus, hollow-beam apertures are provided that define a substantially annular aperture having very narrow radial width. In a planar embodiment, triangular portions are provided at a midline of a first plane member. The triangular portions have respective angled edges and tips that narrow to a bridge supporting a circular portion. Semicircular cutouts are provided at the midline of respective forward edges of two second members. The radius of each semicircular cutout is slightly larger than the radius of the central portion. As the second members are urged together, a substantially annular aperture is formed between the semicircular cutouts and the central portion. The annular aperture can have extremely narrow width. In other embodiments, a block of beam-absorbing material defines a cylindrical portion having a diameter equal to the diameter of an axial beam-absorbing body, and defines a cylindrical opening, having a diameter equal to the intended outer diameter of the annular opening, beneath the cylindrical portion. Rotation-symmetric portions that are thin in a beam-transmission direction are removed selectively to form a hollow-beam aperture defining an opening that, in a plan view, is substantially annular except for portions missing from the ring.
	summary
	claims	1. An active zone of a lead-cooled fast reactor, comprising a homogeneous uranium-plutonium nitride fuel which is contained in geometrically identical shells of cylindrical fuel elements, wherein the fuel elements are arranged in fuel assemblies so that a mass fraction of the fuel in the active zone is a minimum of 0.305, said fuel assemblies create a central part, an intermediate part and a peripheral part of the active zone, wherein a diameter (d1) of the central part of the active zone ranges from 0.4 to 0.5 of an effective diameter (D) of the active zone, while a height (h1) of the fuel column in the fuel elements of the fuel assemblies in the central part of the active zone is from 0.5 to 0.8 of a height (H) of the fuel column in the fuel elements arranged in the fuel assemblies in the peripheral part of the active zone, and a diameter (d2) of the stepped intermediate part of the active zone ranges from 0.5 to 0.85 of the effective diameter (D) of the active zone, while heights (h2) of the fuel columns in the fuel elements in the fuel assemblies forming the stepped intermediate part are from 0.55 to 0.9 of the height of the fuel column in the fuel elements arranged in the fuel assemblies in the peripheral part of the active zone.
043476228	summary	BACKGROUND OF THE INVENTION This invention relates to a method for surveillance of the nuclear fuel in fuel elements and fuel bundles to detect any diversion of the nuclear material therefrom. Typically nuclear fuel, such as uranium or plutonium oxide, is in the form of pellets or powder contained in a suitable container such as an elongated cladding tube sealed by end plugs to form a fuel element as shown, for example, in U.S. Pat. No. 3,378,458. As typically used in a nuclear reactor core, a number of fuel elements are supported in spaced array between upper and lower tie plates to form a separately replaceable fuel assembly or bundle as shown, for example, in U.S. Pat. No. 3,689,358. A sufficient number of such fuel bundles are arranged in a matrix, approximating a right circular cylinder, to form the nuclear reactor core capable of self-sustained fission reaction. Periodically the core is refueled by replacement of some of the fuel bundles to restore the necessary reactivity. Thus the fuel bundle is the normal unit of fuel material transfer and use throughout the fuel cycle. That is, the fuel elements are assembled into bundles at the fuel fabrication factory. The bundles are shipped to the reactor and placed in the core. Eventually the bundles are removed from the core and stored as such or are shipped to a reprocessing plant. An object of this invention is to provide a method and apparatus for obtaining a unique indication or signature of individual fuel elements and individual fuel bundles at any point in the fuel cycle to assure that the fuel material therein has not been removed or otherwise tampered with. Another object is to provide nondestructive surveillance of nuclear fuel elements and bundles. SUMMARY This invention is based upon the known fact that nuclear fuel contains varying amounts (typically in the order of several hundred parts per million) of tramp ferromagnetic particles, particularly particulate iron, primarily from oxidative corrosion and abrasion of the fuel processing equipment. This invention is based further on the recognition that the ferromagnetic particle distribution (that is, the sizes of the particles, the amount or number of particles and the location of the particles) is random. Hence the ferromagnetic particle distribution is unique for each fuel element and for each bundle of fuel elements. These randomly distributed ferromagnetic particles cause changes in magnetic susceptibility proportional to the changes in the ferromagnetic particle content as the fuel element or fuel bundle is passed through a constant or direct current magnetic field. If desired, known amounts of ferro or paramagnetic material could be added at random or at known positions in the fuel material. This added magnetic material could be used to augment the tramp magnetic material and, especially if placed in known positions could be used to provide, for example, type identification of the fuel material. Thus in accordance with the invention the fuel element or fuel bundle is passed through a sensing coil in a constant magnetic field and the signals produced by the sensing coil, due to changes in magnetic susceptibility caused by the changing ferromagnetic particle content, are recorded to provide a unique signature of the particular fuel element or fuel bundle. At any subsequent time the particular fuel element or fuel bundle similarly can be scanned again whereby the subsequent signature thus obtained can be compared to the originally recorded signature to determine whether or not any fuel material in such fuel element or fuel bundle has been removed or otherwise tampered with. If the fuel material contains an additive, such as a burnable neutron absorber, with high paramagnetic susceptibility and in varying amounts along the length of the fuel element or fuel bundle, the contribution of such paramagnetic material to the signature signal can be determined and separated from the contribution of the ferromagnetic material. The fuel element or fuel bundle is passed through two different constant magnetic fields of different strengths and the differential susceptibility changes in the two different magnetic fields is determined. For some applications it may be desirable to obtain and record the signature signals of both the ferromagnetic and paramagnetic material. The fuel surveillance method of the invention provides the outstanding advantage of requiring no changes in the fuel element or fuel bundle design or composition.
	summary
	description	This application is a National Phase of PCT/EP2011/054325, filed Mar. 22, 2011, entitled, “MOBILE SYSTEM FOR INTERVENTION IN AN ATMOSPHERE OF RADIOACTIVE GAS, NOTABLY TRITIUM”, which claims the benefit of French Patent Application No. 10 52080, filed Mar. 23, 2010, the contents of which are incorporated herein by reference in their entirety. The present invention concerns a mobile system for intervention in an atmosphere of radioactive gas, notably tritium. It applies in particular to maintenance and sanitation interventions in a tritium atmosphere. Interventions on confinement barriers, which are used in installations handling tritium, carry a high risk of dissemination of this radioelement, and of contamination of persons undertaking the intervention. Tritium is, indeed, very volatile. It is therefore necessary to install individual and collective protections for these persons, in order to minimise risks of external exposure. A removable barrier is generally installed in order partially to reconstitute a static confinement function. This removable barrier is a solid wall consisting of plastic films or easy-assembly assembled elements. The system forming the object of the invention completes this removable barrier, adding to it a function for controlled extraction of the air contained in the intervention zone, which may contain radioactive gas, whilst keeping the intervention zone at a slightly lower pressure than the exterior of this zone. This controlled extraction function, with the maintenance of a slightly lower pressure, is commonly called dynamic confinement. This dynamic confinement, associated with the installed barrier, creates a pressure gradient which favours transfer of the tritium in a particular direction. The tritium is then generally evacuated from the intervention zone to a ventilation pipe which forms part of the installation where the intervention zone is located. During an intervention, the optimum conditions for nominal operation of the installation are reconstituted. It should be stated immediately that the present intervention combines, with the dynamic confinement function, various items of equipment which enable not only monitoring of the intervention conditions, but also detection of the failure of an element. Operators who undertake the intervention are thus notified, in situ, of any deterioration of the conditions in which they are accomplishing this intervention. Certain maintenance or dismantlement operations require that the confinement function of installations where tritium is handled is degraded. These operations consist, for example, in opening sealed enclosures, or portions of pipes or containers. They are undertaken in an atmosphere where radioactive atmospheric contamination may be substantial, notably when the installation of a protection against dust dissemination is installed in the intervention zone. Consequently these operations can rapidly become disadvantageous for the operators, in terms of dosimetry. An intervention is generally undertaken in a ventilated room, the atmosphere of which is monitored in order to determine its tritium content. However, the zone in which tritium is discharged into the air can be very localized, or even point-like; in addition, dilution in the atmosphere of the room and detection of the activity which is due to tritium are not immediate and can lead to contamination of the operator undertaking the intervention, by inhalation or percutaneous transfer. In order to prevent surface contamination of rooms or facilities by extremely fine dusts with a very high tritium specific activity, removable protection is almost always installed in the location of an operation. This in situ protection prevents the tritium from being diluted by diffusion, and detected by permanent devices fitted in the rooms. On the other hand, dynamic confinement devices and also monitoring and signalling devices are commercially available, but these have no real consistency between them. In addition, these commercially available devices do not have an intrinsic safety function. One aim of the present invention is to remedy these disadvantages. It concerns a modular and independent system, enabling optimum safety of the operators to be guaranteed during operations to deconfine tritiated circuits or waste. According to a preferred embodiment, this system provides the following functions in a consistent manner: a ventilation function by means of an independent ventilator, a function for permanent measurement of the volume activity of the tritium by means of an ionisation chamber, and an acoustic and visual signalling function, which is positioned remotely in the intervention zone. The independent ventilator is fitted with a device for filtering and adjusting the flow rate using a damper; the discharge of the ventilator can be connected to the general ventilation network of the room where the system is installed, by means of appropriate devices; the extraction flow rate is continuously measured, and configurable thresholds are monitored. The ionisation chamber is fitted with a device of the Venturi type in order to extract gaseous samples from the ventilation flow, and with a device to check continuously the validity of the measurement by monitoring the flow rate; in addition, the recording of the measured variables and the digital processing thereof are carried out. Knowledge of the tritium concentration over time enables the dose absorbed by each operator undertaking the intervention to be known. In precise terms, the object of the present invention is a system for intervention in a radioactive gas atmosphere, notably a tritium atmosphere, where the system is characterised in that it includes: a dynamic confinement device including: a removable confinement barrier, able to surround an intervention zone, and a controlled air extraction device, able to keep the intervention zone at a lower pressure than the exterior of this zone, a monitoring device, to monitor the radioactive gas concentration in the air of the intervention zone, and a detection and signalling device, to detect an exceedance of a predefined threshold by this concentration, and to signal the exceedance to the person or persons present in the intervention zone. According to a preferred embodiment of the system forming the object of the invention, the controlled air extraction device includes: a filtration device, to filter any dust in the air extracted from the intervention zone, an adjustment device, to adjust the flow rate of the air which is extracted, and a ventilation device. The system preferably also includes a device for measuring the flow rate of the air which is extracted. According to a preferred embodiment of the invention, the monitoring device includes a device for measuring the volume activity of the radioactive gas. The device for measuring the volume activity of the radioactive gas preferably includes: an ionisation chamber, and a device to cause samples of the extracted air to flow in the ionisation chamber. The device to cause the samples to flow in the ionisation chamber preferably includes: a first device of the Venturi type to extract the samples, and a second device of the Venturi type to restore the extracted samples. This device preferably also includes: a turbine to increase the flow of the samples in the ionisation chamber, and a device to adjust the flow rate of the extracted samples. The system forming the object of the invention preferably also includes a device for measuring the air flow rate in the ionisation chamber. The example of the invention, which is illustrated schematically by the appended FIGURE, is a system for intervention in a tritium atmosphere. This system includes a dynamic confinement device including: a removable confinement barrier 2, able to surround an intervention zone 4 (enclosure or working area), and a controlled air extraction device 6, able to keep intervention zone 4 at a lower pressure than the exterior of this zone. The system represented in the appended FIGURE also includes: a monitoring device 8, to monitor the tritium concentration in the air of intervention zone 4, and a detection and signalling device 10, to detect the exceedance of a predefined threshold by this concentration, and to signal the exceedance to the person or persons present in intervention zone 4. Controlled air extraction device 6 includes: a filtration device 12, to filter any dust in the air which is extracted from intervention zone 4, an adjustment device 14, to adjust the flow rate of the air which is extracted, and a ventilation device 16. In the example, device 12 is a high-performance dust-filtering device; adjustment device 14 is an adjustment damper, enabling the air flow rate to be adjusted according to the volume of zone 4 (for example, the volume of the enclosure), and according to the desired renewal of the air; and ventilation device 16 is an extraction turbine. The system represented in the appended FIGURE also includes a device 18 for measuring the flow rate of the air which is extracted. Monitoring device 8 includes a device for measuring the volume activity of the tritium, including: an ionisation chamber 20 (flow-through ionisation chamber), and a device 22 to cause samples of the extracted air to flow, in ionisation chamber 20, at a flow rate which, in the example, is equal to at least 2.5 m3 per hour. Device 22 to cause the samples to flow in ionisation chamber 20 includes a first device 24 of the Venturi type to extract the samples, and a second device 26 of the Venturi type to restore the extracted samples. Device 22 to cause the samples to flow also includes: an extraction turbine 28 to increase the flow of the samples in ionisation chamber 20, and a device 30 (a valve in the example) to adjust the flow rate of the extracted samples. The inlet of ionisation chamber 20 is preferably fitted with a device (not represented) to heat the samples of air reaching it, notably in order to prevent disruptions of the measurements due to the presence of moisture in the air. The system represented in the appended FIGURE also includes a device 32 for measuring the air flow rate in ionisation chamber 4. The system represented in the appended FIGURE is fitted with an air extraction circuit which is constructed from flexible tubes 34, 36, 38 and 40. This circuit enables air to be extracted from zone 4 and to be conveyed in a ventilation pipe 42 (extraction network). Arrows 44 indicate the direction of flow of the air in the circuit. As can be seen, this circuit is connected, on one side, to zone 4 through a device 46 for passage or connection of flexible tube 34, which is fitted to the removable confinement barrier and, on the other side, to pipe 42 through a sealed flange 48, which is fitted to this pipe. In the circuit, starting at passage or connection device 46, filter 12, damper 14 and turbine 16 are found in succession. Tube 34 connects passage or connection device 46 to filter 12; tube 36 connects damper 14 to filter 12; tube 38 connects turbine 16 to damper 14; and tube 40 connects flange 48 to turbine 16. In addition, flow rate measurement device 18 is installed on tube 36. On the other hand, the device to cause samples 8 to flow includes in succession Venturi type device 24, valve 30, chamber 20, turbine 28, another control valve 50 and other Venturi type device 26. These constituents of device 8 are connected to one another through pipes such as pipe 52. The flow direction of the extracted air samples is represented symbolically by arrows 54. It can also be seen that devices 24 and 26 are “inserted” in flexible tube 40. More specifically, flexible tube 40 consists of two portions, and the devices are installed in a metal sleeve 55, through which the two portions are connected to one another. Thus, the air samples are extracted in tube 40, through device 24, and return to it through device 26. In addition, flow rate measurement device 32 is installed in the pipe which connects chamber 20 to valve 30. Detection and signalling device 10 includes electronic means 56 for processing the electrical current which is supplied by ionisation chamber 20, to determine the tritium concentration in the air. However, before processing the current is amplified by a preamplifier 58. Indeed, this current which is due to the disintegration of tritium is weak, of the order of 10−15 A to 10−10 A, and must be amplified before being processed in means 56 (which are equipped with an amplifier (not represented)). Device 10 is equipped with signalling means 60. These means 60 are placed in intervention zone 4 and are designed to inform, by an acoustic and visual signal, the operator or operators working in this zone, when the tritium concentration in the air of zone 4 exceeds a predefined value. In what follows clarifications are given concerning the various constituents of the system represented in the appended FIGURE. Let us firstly return to independent ventilator (turbine) 16, which is associated with filtration device 12. Suction, through flexible tubes upstream from this ventilator, enables the tritium sources to be collected as close as possible to them, even in completely isolated zones. The suction flow rate may be adjusted by means of damper 14. Purely as an indication, and in no way restrictively, a ventilator having the following characteristics is used: 2760 revolutions per minute-3 A-0.18 kW-13 kg-two speeds; and the flow rate is equal to 700 m3 per hour. In practice, to prevent the accumulation of tritium in the working area, and to provide a low-pressure gradient favourable to the non-dissemination of radioactive substances, the value for hourly renewal of air in zone 4, for the dynamic confinement function, varies between 10 and 15 (10 to 15 renewals of the air of the zone per hour). A value equal to 15 is chosen for the zones where tritiated liquids are present. The ventilator therefore enables coverage of a volume of up to 50 m3. Flow rate measuring device 18 is a hot wire sensor. It is associated with an indicator on which the results of the measurements are reported and flow rate thresholds are indicated. Purely as an indication, and in no way restrictively, this sensor is a thermal sensor with a nickel resistor; it is 120 mm in length; the rod contained in this sensor is of a diameter equal to 10 mm; the sensor's measuring span is from 0.2 m/s to 200 m/s; the sensor's measuring range is from 0 m3/h to 700 m3/h; and the sensor has an analog output which ranges from 4 mA to 20 mA. Filtration device 12 enables the prevention of dissemination outside the intervention zone of dust generated during the intervention (for example due to cutting or resuspension actions), and which is potentially very contaminated. Purely as an indication, and in no way restrictively, filtration device 12 includes four paper and glass fibre filters in a box; its uranine efficiency is over 99.98%; nominal delta P of this filter is equal to 250 m3/h/Pa; and the maximum temperature tolerated by the filter is equal to 200° C. Downstream from ventilator 16, metal sleeve 55, fitted with extraction and discharge devices of the Venturi type 24 and 26 provides a pressure difference required for the flow of the air and of the tritium in measuring device 8 which is fitted with ionisation chamber 20. The connections between the different constituents of the ventilation chain are provided by the flexible tubes mentioned above. Purely as an indication, and in no way restrictively, SEMA tubes, made from 0.6 mm thick PVC-coated polyester are used; they are reinforced by copper-plated steel turns supplied by the company ISOTEC. Clarifications are now given concerning the tritium measuring and detection chain. In the example, ionisation chamber 20 is of the GCC 80 EVP type and has a useful volume of 10 liters. A β− particle is emitted when tritium disintegrates. This particle transfers its energy to the ambient environment, creating ion-electron pairs in it. The ions and the electrons are collected on two electrodes (not represented) contained in chamber 20 (measuring chamber) where a 300 V polarisation voltage has been established. A current is thus generated the value I of which is directly proportional to the tritium volume concentration. Since the tritium oxide (HTO) form is the more disadvantageous in terms of dosimetry (it is more contaminating than the HT form for an operator) we take this form as the operational value. In other words, the calculations are made with this HTO form. Current I is given by the following formula: I = C × V × 10 - 3 × E × 1 W × 1 , 6 × 10 - 19 In this formula I represents the value of the ionisation current, expressed in amperes, and C is the tritium concentration in air, expressed in Bq·m−3. However, in accordance with general radio protection rules of the Atomic Energy Commission, operational limits are now expressed in a unit which is noted RCAtritiated water. For a given radionuclide, an RCA corresponds to the average activity concentration, in Bq·m−3, which leads to an effective committed dose of 25 μSv in one hour's presence. And 1 RCAtritiated water is equal to 7.72×105 Bq·m−3. In addition, in the formula: V represents the volume of the ionisation chamber, expressed in dm3; E represents the average energy of the β− spectrum of tritium; it is expressed in eV and is equal to 5.7×103 eV; W represents the energy which is required to form a pair of ions in air; it is expressed in eV and is equal to 33.7 eV; 1.6×1019 represents the charge of the electron, expressed in coulombs. The current in question is weak. It is amplified using preamplifier 58. The latter is associated with an amplifier to convert this current into a tritium volume activity value (in Bq/m3). Preamplifier 58 is directly installed in chamber 20 (detector) and provides: a calculation of the ionisation voltage, acquisition and digitisation of the ionisation current, and communication with the measuring resources (device 10). The amplifier (not represented) is a DT137T amplifier in the described example. It allows local display of the measured value (value of I, converted into RCA) and processing of it: to inform the users whenever a configurable threshold is exceeded, and to calculate totals by integration. The main characteristics of this amplifier are as follows: operating temperature: −10° C. to 40° C.; electrical power: 220 V-50 Hz-100 W; measuring span: 10−1 LPCA to 1011 LPCA (LPCA: limit for admissible concentration); choice of volume activity units: RCA, LDCA, LPCA, CMA, Ci/m3, Bq/m3 (RCA: atmospheric concentration benchmark; LDCA: admissible concentration limit; CMA: authorised maximum concentration); choice of activity units: Ci, Bq; local indication using an LCD graphical display −240×64 points; four-key sealed membrane keypad; analog outputs: 0/10 VDC; digital input/output: RS232C; threshold exceedance alarms: a 5 A/250 V changeover contact; state fault alarm: a 5 A/250 V changeover contact; accuracy: ±0.3% of the measurement; sensitivity: 0.002 LPCA; stability: ±0.1% of the measurement; repeatability: ±+0.1% of the measurement; and response time: less than 10 s for 100% variation. In device 10 a digital recorder (not represented) enables the volume activity values generated by the DT137T amplifier to be archived. The extraction flow rate values are also recorded and, after integration, enable the outcome of the intervention to be recorded in terms of discharges, and also the dosimetric outcome. This recorder is fitted with removable USB storage devices, and allows recording over 320 days. Turbine 28 allows the contaminated air to flow in the ionisation chamber, in addition to the pressure difference created by the previously described Venturi type device. The flow rate of the air traversing the ionisation chamber is adjusted by valve 30, to which valve 50 is added in the example. This flow rate is greater than or equal to 2.5 m3/h. It is continuously controlled by device 32 which, in the example, is a hot wire sensor with an alarm. Purely as an indication, and in no way restrictively, this sensor has the following characteristics: it includes a nickel resistor; it is 120 mm in length; is measuring span is 0.2 m/s to 200 m/s; the rod which it includes is 10 mm in diameter; its measuring range is from 0 m3/h to 50 m3/h; and it has an analog output ranging from 4 mA to 20 mA. Means 60 allow signalling which is positioned remotely in the working area. They include a flash bulb and a buzzer, giving a signal which is both acoustic and visual. If a threshold is exceeded the operators are thus immediately informed of the risk of contamination in the place of the operation. They can then take all necessary measures to safeguard themselves, and do so extremely rapidly. The system described enables three modules to be associated, which can be deployed independently of one another in the location of the intervention during which there is a risk of contamination by tritium. Indeed, it enables the risk of contamination by tritium (by inhalation or by percutaneous transfer) to be prevented, by encouraging dilution in air and evacuation of the tritium. It also allows rapid detection of a rise in contamination by tritium as close as possible to the discharge point, thus enabling the operators to safeguard themselves. In addition, the type of signalling used enables the operators to be alerted in all circumstances (noise, sparks, projections). Due to its modularity and the choice of elements comprising it, the system can be adapted to many circumstances, with a high degree of safety: variable volumes, confined intervention zone, ease of connection (electrical and ventilation), compliance with principle of non-dissemination, and intrinsically safe system, with detections associated with the system's different functions. In the invention there is consistency between the different facilities used, notably through the reproduction, with a removable system, of conditions of safety equivalent to those of fixed devices of an installation where tritium is found (dynamic confinement, monitoring and detection, information provided to agents). After the interventions a complete assessment can be produced with regard to the quantity of tritium involved and the changes in the tritium concentration in the air. Knowledge-building can also be accomplished from dosimetric feedback. In the example described the signalling is acoustic and visual, but in other examples it could be acoustic or visual. In addition, the given example concerns interventions in a tritium atmosphere. But it can be suitable for interventions in any radioactive gas atmosphere.
	summary
	description	This application claims priority to U.S. Provisional Patent Application Ser. No. 62/372,976 filed on Aug. 10, 2016, which is hereby incorporated by reference in its entirety. Nuclear fuel rods are used to generate electrical power, and provide an attractive alternative to the generation of electrical power from fossil fuels. Nuclear fuel rods can be utilized to create a nuclear reaction that may be used to heat water, generating steam to drive a turbine. The turbine may be coupled to a generator, thereby producing electrical energy. Over time, the nuclear fuel rods may become “spent,” and may no longer be useful to sustain a nuclear reaction. While no longer able to sustain a useful nuclear reaction, the nuclear fuel rods may continue to produce heat that must be dissipated and may emit radiation that must be contained. Conventionally, these spent nuclear fuel rods may be kept within a storage pool for a period of time while residual heat from the spent nuclear fuel rods is dissipated. This is sometimes referred to as “wet storage” of the spent nuclear fuel rods. The storage pools are typically located within a nuclear facility, and space within the storage pools may be limited. Once the spent nuclear fuel rods have sufficiently cooled, the spent nuclear fuel rods may be removed from the storage pool and placed within a fuel storage cask for “dry storage.” Conventional fuel storage casks may include cooling vents that allow ambient air to draw heat away from the fuel storage cask via convection, which assists in maintaining the fuel storage cask at an operable temperature. However, these vents may become blocked by foreign objects such as debris, which may restrict the flow of ambient air, thereby reducing the amount of heat drawn away from the fuel storage cask. In some circumstances, blockages of the vents may necessitate that fuel cask and/or the fuel rods within the fuel cask be moved to a storage pool to prevent the fuel rods from overheating and degrading the fuel cask. Accordingly, the vents may require periodic inspection and maintenance to ensure that the fuel storage cask is maintained at an operable temperature, which may increase operating costs. Accordingly, a need exists for alternative fuel storage casks and cooling systems for fuel storage casks including a self-contained cooling system. In one embodiment, a fuel storage cask includes an outer shell having a length extending from a first end to a second end of the outer shell, the outer shell defining an inner cavity circumscribed by the outer shell, an outer perimeter extending around the outer shell, an inner perimeter positioned inward from the outer perimeter, and a cooling circuit extending along the length of the outer shell, the cooling circuit including an inner passage, and an outer passage, a coolant positioned within the cooling circuit, where the coolant is configured to move through the inner passage, absorbing heat from the inner cavity of the outer shell, and the coolant is configured to move through the outer passage, dissipating heat through the outer perimeter of the outer shell, and a lid coupled the outer shell, where the lid covers the inner cavity of the outer shell. In another embodiment, a cooling system for a fuel storage cask includes an inner passage extending around and circumscribing an inner perimeter of a fuel storage cask and extending along a length of the fuel storage cask, the length being evaluated between a first end and a second end of the fuel storage cask positioned opposite the first end, an outer passage positioned outward from the inner passage and in fluid communication with the inner passage, and a coolant positioned within the inner passage and the outer passage, where the coolant is configured to move through the inner passage, absorbing heat from an inner cavity of the storage cask, and the coolant is configured to move through the outer passage, dissipating heat through an outer perimeter of the storage cask. In yet another embodiment, a method for cooling a fuel storage cask includes providing a cooling circuit including an inner passage extending around and circumscribing an inner perimeter of a fuel storage cask, and an outer passage positioned outward of and in fluid communication with the inner passage, providing a coolant positioned within the inner passage and the outer passage, heating the coolant within the inner passage with a heat source positioned within an inner cavity of the fuel storage cask, moving the coolant within the inner passage upward in a vertical direction, cooling the coolant within the outer passage by dissipating heat to an ambient medium, and moving the coolant within the outer passage downward in the vertical direction. Various embodiments of fuel storage casks now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the fuel storage cask are shown. Indeed, these fuel storage casks may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. The term “or” is used herein in both the alternative and conjunctive sense, unless otherwise indicated. The terms “illustrative” and “exemplary” are used to be examples with no indication of quality level. Terms are used herein both in the singular and plural forms interchangeably. Like numbers refer to like elements throughout. Many modifications and other embodiments of the fuel storage casks set forth herein will come to mind to one skilled in the art having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the fuel storage casks described herein are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. As used herein, the term “thermally coupled” means that thermal energy may be exchanged between various components described herein. Thermally coupled components may be in direct or in indirect contact with one another. Fuel storage casks are used to store spent nuclear fuel, such as spent nuclear fuel rods that may result from electrical power generation from nuclear power. Although the spent nuclear fuel may have been removed from a nuclear reaction, the spent nuclear fuel may continue to generate heat within the fuel storage cask, and it is desirable to dissipate heat from the spent nuclear fuel to maintain the fuel storage cask at an acceptable temperature. Fuel storage casks as described herein include a shell that defines a cooling circuit that assists in dissipating heat from the fuel storage cask. Referring initially to FIG. 1, a perspective view of a fuel storage cask 100 is schematically depicted. The fuel storage cask 100 includes an outer shell 110 including a first end 102 and a second end 104 positioned opposite the first end 102. The fuel storage cask 100 has a length 106 evaluated between the first end 102 and the second end 104. The length 106 may be selected to such that a spent nuclear fuel rod may be positioned within and encapsulated by the fuel storage cask 100. While in the embodiment depicted in FIG. 1 the fuel storage cask 100 and the outer shell 110 have a generally cylindrical shape, it should be understood that the fuel storage cask 100 and the outer shell 110 may have any suitable shape for storing spent nuclear fuel. As non-limiting examples, the cask and shell may be include a rectangular prism shape, a cubical shape, a conical shape, or a spherical shape. The outer shell 110 may be formed from any suitable construction materials or combination of materials, including but not limited to, concrete, cement, cermet, metal, composites, or the like. Referring to FIG. 2, a top view of the fuel storage cask 100 of FIG. 1 is schematically depicted. The fuel storage cask 100 further includes a lid 120 that is coupled to the first end 102 of the outer shell 110. When installed, the lid 120 covers an opening of the outer shell 110, such that the lid 120 may encapsulate an interior of the outer shell 110. In some embodiments, the lid 120 may cover the only opening that allows access the interior of the outer shell 110. In other embodiments, the fuel storage cask 100 may also include another lid coupled to the second end 104 (FIG. 1) of the outer shell 110, covering a second opening positioned at the second end of the outer shell 110. The lid 120 or lids may be coupled to the outer shell 110 by any suitable methodology, including but not limited to, welding, brazing, mechanical fasteners, structural adhesives, or the like. Referring to FIG. 3A, a section view of the fuel storage cask 100 along section 3A-3A of FIG. 2 is schematically depicted. The fuel storage cask 100 is in a “vertical” orientation, such that the first end 102 of the fuel storage cask 100 is positioned above the second end 104 of the fuel storage cask 100 in a vertical direction. The outer shell 110 defines an outer perimeter 112 that extends around the outer shell 110. The outer perimeter 112 may optionally include fins 115 that assist in transferring heat from the outer shell 110 to an ambient medium 10 outside of the outer shell 110. In embodiments, the fins 115 may include any suitable geometry and may be oriented in any suitable matter to assist in transferring heat energy from the outer shell 110 to the ambient medium 10. The outer shell 110 further defines an inner perimeter 114 that defines and circumscribes an inner cavity 116. The inner perimeter 114 is positioned between the outer perimeter 112 and the inner cavity 116. In embodiments, the inner perimeter 114 and the outer perimeter 112 include similar and concentric shapes. For example, in the embodiment shown in FIG. 3A, the inner perimeter 114 and the outer perimeter 112 include concentric circular shapes. In other embodiments, the inner perimeter 114 and the outer perimeter may include different and/or non-concentric shapes. For example and without limitation, one of the inner perimeter 114 and the outer perimeter 112 may include a circular shape, while the other of the inner perimeter 114 and the outer perimeter 112 includes a square or rectangular shape. The inner perimeter 114 and the outer perimeter 112 may include any suitable shape to accommodate spent nuclear fuel rods stored within the inner cavity 116 of the outer shell 110. In embodiments, the outer shell 110 of the fuel storage cask 100 includes a shielding 117 that restricts and/or prevents radiation from spent fuel rods within the inner cavity 116 from passing through the outer shell 110. The shielding 117 may include various materials that restrict and/or prevent radiation, such as may be emitted from spent nuclear fuel rods, from passing through the shielding 117, and may be formed from materials such as lead, iron, concrete, or the like. The shielding 117 may be positioned to encapsulate the inner cavity 116, such that shielding 117 is positioned between the inner cavity 116 and the outer perimeter 112 of the outer shell 110, so as to prevent a “direct path,” or route for radiation emitted from within the inner cavity 116 to reach areas outside of the outer shell 110 without first passing through the shielding. In other words, shielding may be positioned throughout the outer shell 110 so as to fully encapsulate the inner cavity 116. In the embodiment depicted in FIG. 3A, the outer shell 110 of the fuel storage cask 100 includes a central axis 111 extending through the outer shell 110, and the outer shell 110 includes a generally cylindrical shape that is symmetrical about the central axis 111. In other embodiments, the outer shell may be asymmetrical about the central axis 111. The fuel storage cask 100 includes a cooling circuit 130 that is positioned between the inner perimeter 114 and the outer perimeter 112 of the outer shell 110, and that extends circumferentially around at least the inner perimeter 114 of the outer shell 110. In the embodiment shown in FIG. 3A, the cooling circuit 130 is generally symmetrical about the central axis 111. The cooling circuit 130 assists in dissipating heat generated by spent fuel rods positioned within the fuel storage cask 100. Referring to FIG. 3B, an enlarged view of the region 3B shown in FIG. 3A is schematically depicted. The cooling circuit 130 includes an inner passage 132 and an outer passage 134 that is positioned outward from the inner passage 132. In embodiments where the outer shell 110 includes a cylindrical shape, the outer passage 134 is positioned radially outward from the inner passage 132. While only a portion of the inner passage 132 and the outer passage 134 is shown, it should be understood that in the embodiment shown in FIG. 3B, the inner passage 132 and the outer passage 134 extend circumferentially around the inner cavity 116. In embodiments, the shielding 117 is positioned between the inner passage 132 and the outer passage 134 and is positioned so as to prevent a “direct path,” or route for radiation emitted from within the inner cavity 116 to reach areas outside of the outer shell 110 without first passing through the shielding. Alternatively, the shielding 117 may be positioned outward of the outer passage 134 and/or inward of the inner passage 132 to prevent radiation emitted from within the inner cavity 116 from reaching areas outside of the outer shell 110. The inner passage 132 and the outer passage 134 each include a generally annular shape that is symmetrical about the central axis 111 (FIG. 3A) of the outer shell 110. Alternatively, the inner passage 132 and the outer passage 134 may include shapes that are asymmetrical about the central axis 111 (FIG. 3A). The cooling circuit 130 includes an exit passage 136 that connects and is in fluid communication with the inner passage 132 and the outer passage 134. In the embodiment depicted in FIG. 3B, the exit passage 136 is positioned at the first end 102 of the outer shell 110 and includes an annular shape that extends circumferentially around the outer shell 110. A coolant 140 is provided within the inner passage 132 and the outer passage 134, and the coolant 140 assists in dissipating heat generated by a heat source such as spent fuel rods positioned within the inner cavity 116 of the outer shell 110. The cooling circuit 130 may be hermetically sealed, such that the coolant 140 is contained within the cooling circuit 130. The inner passage 132 of the cooling circuit 130 is thermally coupled to the inner cavity 116 such that heat generated by spent fuel rods within the inner cavity 116 may be transferred to the inner passage 132, and more particularly to the coolant 140 within the inner passage 132. In the embodiment shown in FIG. 3B, the coolant 140 flows upward through the inner passage 132, where it absorbs heat energy from the inner cavity 116. The upward flow of the coolant 140 may be induced by convective flow of the coolant 140 resulting from the absorbed energy from the inner cavity 116. For example, as the coolant 140 absorbs heat energy from the inner cavity 116, a temperature of the coolant 140 may increase and a density of the coolant 140 may decrease, causing the coolant 140 to rise as a result of natural convection. Alternatively or additionally, the flow of the coolant 140 through the inner passage 132 may be induced, such as with a pump, and the pump may induce flow of the coolant 140 upward or downward in the vertical direction within the inner passage 132. Upon reaching the top of the inner passage 132, the coolant 140 flows radially outward through the exit passage 136 toward the outer passage 134. The coolant 140 then flows downward through the outer passage 134, dissipating heat to an ambient medium 10 surrounding the outer shell 110. The ambient medium 10 may include gas, liquid, and/or a solid surrounding the outer shell, such as ambient air. The downward flow of the coolant 140 through the outer passage 134 may similarly be induced by convective flow of the coolant 140 as energy from the coolant 140 is transferred to the ambient medium 10. In particular, the coolant 140 within the outer passage 134 is positioned distal from the inner cavity 116 as compared to the coolant 140 within the inner passage 132, reducing the amount of heat absorbed by the coolant 140 within the outer passage 134 as compared to the inner passage 132. Further, the outer passage 134 is thermally coupled to the ambient medium 10 surrounding the outer shell 110, such that heat from the coolant 140 within the outer passage 134 is transferred to the ambient medium 10. As the coolant 140 transfers heat energy to the ambient medium 10, the temperature of the coolant 140 may decrease and the density of the coolant 140 may increase, causing the coolant 140 to move downward as a result of natural convection. Referring to FIG. 3C an enlarged view of the region 3C shown in FIG. 3A is schematically depicted. At the second end 104 of the outer shell 110, the outer passage 134 is in fluid communication with the inner passage 132 through a return passage 138. While only a portion of the return passage 138 is shown in FIG. 3C, it should be understood that the return passage 138 includes an annular shape that extends circumferentially around the outer shell 110. As the coolant 140 flows downward through the outer passage 134, the coolant 140 continues to dissipate heat to the ambient medium 10, thereby lowering the temperature of the coolant 140. Alternatively or additionally, the flow of the coolant 140 through the outer passage 134 may be induced, such as with a pump, and the pump may induce flow of the coolant 140 upward or downward in the vertical direction within the outer passage 134. When the coolant 140 reaches the second end 104, the coolant 140 flows radially inward through the return passage 138 toward the inner passage 132. In some embodiments, the return passage 138 may include an optional wick 142 that assists in moving coolant 140 from the outer passage 134 toward the inner passage 132, such as through capillary action. However, in other embodiments, convective flow of the coolant 140 alone induces movement of the coolant 140 radially inward through the return passage 138. Upon reaching the inner passage 132 through the return passage 138, the coolant 140 begins to flow upward again through the inner passage 132, again absorbing heat from the inner cavity 116. Referring to FIG. 4, the overall flow of coolant 140 through the cooling circuit 130 is schematically depicted. As described above, when the outer shell 110 is in a vertical orientation, the coolant 140 flows upward through the inner passageway 132 toward the first end 102, absorbing heat from the inner cavity 116, such as from spent fuel rods positioned within the inner cavity 116. As the coolant 140 flows upward, the coolant 140 reaches the first end 102 of the outer shell 110, and moves outward through the exit passage 136. After passing through the exit passage 136, the coolant 140 flows downward through the outer passage 134, and dissipates heat to the ambient medium 10. After cooling, the coolant 140 reaches the second end 104 and flows inward through the return passage 138 back to the inner passage 132 to again absorb heat from the inner cavity 116. The fuel storage cask 100 optionally includes the wick 142 positioned in the outer passage 134, the return passage 138, and/or the inner passage 132, and may assist in moving coolant 140 through the return passage 138 to the inner passage 132, for example, when the outer shell 110 is not in the vertical orientation. In embodiments, the coolant 140 may include a gas, a liquid, or a gas/liquid mix that absorbs heat from the inner cavity 116. For example, in some embodiments, the coolant 140 includes helium or the like. As the inner passage 132 and the outer passage 134 include annular shapes that extend circumferentially around the outer shell, the inner passage 132 and the outer passage 134 may assist in dissipating heat from the fuel storage cask 100. For example, as the inner passage 132 includes an annular shape that extends circumferentially around the inner perimeter 114 of the inner cavity 116, the inner passage 132 may fully encapsulate the inner cavity 116. As the inner passage 132 encapsulates the inner cavity 116, the amount of heat that may be transferred from the inner cavity 116 may be increased as the inner passage 132 may have a relatively high amount of surface area exposed to the inner cavity 116 as compared to an inner passage that does not fully encapsulate the inner perimeter 114. Similarly, in embodiments, the outer passage 134 includes an annular shape that extends circumferentially around the outer shell 110, which may increase the amount of heat that may be transferred from coolant 140 within the outer passage 134 to the ambient medium 10 as compared to an outer passage that does not have an annular shape that extends around the outer shell 110. Referring to FIG. 5, a front view of the lid 120 of the fuel storage cask 100 is schematically depicted. The lid 120 generally a cooling circuit 122, and the lid 120 optionally includes fins 115 positioned on top of the cooling circuit 122 and a heat sink 121 positioned below the cooling circuit 122. Referring to FIG. 6, a section view of the lid 120 of the fuel storage cask 100 along 6-6 is schematically depicted. In the embodiment depicted in FIG. 6, the lid 120 includes the lid cooling circuit 122 positioned above the heat sink 121. The heat sink 121 may include fins 115 that are configured to thermally couple the outer shell 110 (FIG. 4) to the lid cooling circuit 122, such as through conduction. The lid 120 may further include shielding 117 and a neutron absorber 124 positioned between the heat sink 121 and the cooling circuit 122. The shielding 117 and the neutron absorber 124 may prevent radiation from passing from the interior of the outer shell 110 (FIG. 4) to the cooling circuit 122. In some embodiments, the lid 120 may optionally include heat pipes positioned around a perimeter of the lid 120 to assist with the dissipation of heat. The lid cooling circuit 122 defines a vapor passage 123 that is in fluid communication with a lid outer passage 125. When installed to the outer shell 110, the vapor passage 123 is thermally coupled to the inner cavity 116 (FIG. 4) of the outer shell 110, while the lid outer passage 125 is thermally coupled to the ambient medium 10, and a coolant 140 is positioned within the vapor passage 123 and the lid outer passage 125. Similar to the cooling circuit 130 of the outer shell 110 (FIG. 4), the lid cooling circuit 122 assists in dissipating heat generated from spent fuel rods stored within the inner cavity 116 of the outer shell 110. Referring collectively to FIGS. 6 and 7, the section view of the lid and a section view of the lid with arrows showing the direction of flow of coolant 140 are depicted, respectively. The coolant 140 within the vapor passage 123 absorbs heat from the inner cavity 116 (FIG. 4) and flows upward, such as through convective flow. The coolant 140 then flows through a lid exit passage 127 that is positioned above the vapor passage 123. The coolant 140 then flows radially outward through lid exit passage 127 to the lid outer passage 125, and exchanges heat energy with the ambient medium 10. Similar to the upward flow of the coolant 140 through the vapor passage 123, the outward flow of the coolant 140 through the lid outer passage 125 may result from convective flow of the coolant 140. Alternatively or additionally, flow of the coolant 140 through the lid outer passage 125 and/or the vapor passage 123 may be induced by a pump that may induce flow of the coolant 140 in any suitable direction through lid cooling circuit 122. In some embodiments, the lid outer passage 125 and the lid exit passage 127 may include a wick or other porous surface that is configured to encourage coolant flow 140 through the lid outer passage 125 and the lid exit passage 127. As the coolant 140 flows through the lid outer passage 125 and exchanges heat with the ambient medium 10, the coolant 140 cools and flows downward to the vapor passage 123 through a lid return passage 129 that is positioned below the lid exit passage 127 and the vapor passage 123. Flowing through the lid return passage 129, the coolant 140 absorbs heat from the inner cavity 116 of the outer shell 110 and returns to the vapor passage 123. In some embodiments, the lid return passage 129 may include a wick or other porous surface that is configured to induce inward flow of the coolant 140 to the vapor passage 123. In this way, the lid cooling circuit 122 may assist in dissipating heat generated by spent nuclear fuel positioned within the inner cavity 116. Similar to the cooling circuit 130 of the outer shell (FIG. 4), the coolant 140 include a gas, a liquid, or a gas/liquid mix that absorbs heat from the inner cavity 116. For example, in some embodiments, the coolant 140 includes helium or the like. As described above, the lid 120 is coupled to a first end 102 of the outer shell 110, and when the outer shell 110 is positioned in a vertical orientation, the lid 120 is positioned proximate to the exit passage 136 (FIG. 4) of the outer shell 110. As the coolant 140 (FIG. 4) absorbs heat, the temperature of the coolant 140 rises, and the coolant 140 within the exit passage 136 may have a higher temperature than coolant 140 at other positions within the cooling circuit 130 (FIG. 4). Put another way, the coolant 140 (FIG. 4) may be at its hottest point within the cooling circuit 130 at the exit passage 136 at the first end 102 of the outer shell 110. Accordingly, by including a lid 120 including a cooling circuit 122, heat from the coolant 140 within the cooling circuit 130 of the outer shell 110 (FIG. 4), as well as heat generated from the inner cavity 116 of the outer shell 110 may be dissipated. Referring collectively to FIGS. 8 and 9, another embodiment of the fuel storage cask 100 is depicted. Similar to the embodiment depicted in FIG. 1 and described above, the fuel storage cask 100 includes the outer shell 110 having the first end 102 and the second end 104 positioned opposite the first end 102. The fuel storage cask 100 further includes the lid 120 coupled to the first end 102, and may include a second lid coupled to the second end 104 of the outer shell 110. Referring to FIG. 10, a section view of the fuel storage cask 100 is depicted along section 8-8 of FIG. 7. Similar to the embodiment described above with respect to FIG. 3A, the outer shell 110 includes a cooling circuit 130 that is positioned between the outer perimeter 112 of the outer shell 110 and the inner perimeter 114. The outer shell 110 includes shielding 117 that restricts and/or prevents radiation from spent nuclear fuel rods within the inner cavity 116 from passing through the outer shell 110. The shielding 117 may include various materials that restrict and/or prevent radiation from passing through the shielding, such as lead, iron, concrete or the like. The shielding may be positioned to encapsulate the inner cavity 116, such that shielding is positioned between the inner cavity 116 and the outer perimeter 112 of the outer shell 110, so as to prevent a “direct path,” or route for radiation emitted from within the inner cavity 116 to reach areas outside of the outer shell 110 without first passing through the shielding. In other words, shielding may be positioned throughout the outer shell 110 so as to fully encapsulate the inner cavity 116. Referring collectively to FIGS. 11 and 12, a section view of the outer shell 110 is depicted along section 9-9 and 10-10 of FIG. 9 is schematically depicted, respectively. In the configuration depicted in FIGS. 11 and 12, the outer shell 110 is oriented in a horizontal direction, such that the first end 102 and the second end 104 (FIG. 9) are similarly positioned in the vertical direction, as opposed to the first end 102 being positioned above the second end 104 in the vertical direction. The cooling circuit 130 includes the inner passage 132 that extends circumferentially around the inner perimeter 114 and includes a generally annular shape. Similarly, the cooling circuit 130 includes the outer passage 134 that extends circumferentially around the inner passage 132 and includes a generally annular shape. Similar to the embodiment described above and depicted in FIGS. 3A-3C, the shielding 117 is positioned between the inner passage 132 and the outer passage 134 and is positioned so as to prevent a “direct path,” or route for radiation emitted from within the inner cavity 116 to reach areas outside of the outer shell 110 without first passing through the shielding. Alternatively, the shielding 117 may be positioned outward of the outer passage 134 and/or inward of the inner passage 132 to prevent radiation emitted from within the inner cavity 116. The coolant 140 is positioned in the inner passage 132 and the outer passage 134 and assists in dissipating heat generated by spent fuel rods positioned within the inner cavity 116 of the outer shell 110. In particular, the inner passage 132 of the cooling circuit 130 is thermally coupled to the inner cavity 116 such that heat generated by spent fuel rods within the inner cavity 116 may be transferred to the inner passage 132, and more particularly to the coolant 140 within the inner passage 132. In the embodiment shown in FIGS. 9 and 10, the coolant 140 flows upward and circumferentially around the inner passage 132, where it absorbs heat energy from the inner cavity 116. The upward flow of the coolant 140 may be induced by convective flow of the coolant 140 resulting from the absorbed heat energy from the inner cavity 116. Alternatively or additionally, the flow of the coolant 140 through the inner passage 132 may be induced, such as with a pump, and the pump may induce flow of the coolant 140 upward or downward in the vertical direction within the inner passage 132. Upon reaching the top of the inner passage 132, the coolant 140 flows upward through the exit passage 136 toward the outer passage 134, which is in fluid communication with the inner passage 132 through the exit passage 136. While only a portion of the exit passage 136 is shown in FIGS. 11 and 12, it should be understood that the exit passage 136 extends along the length 106 (FIG. 8) of the outer shell 110. By including an exit passage 136 that extends along the length 106 (FIG. 8) of the outer shell 110, the exit passage 136 allows upward flow of the coolant 140 to the outer passage 134 from the inner passage 132 when the outer shell 110 is in the horizontal orientation as shown in FIGS. 11 and 12, as compared to the embodiment shown in FIG. 3B, in which the outer shell 110 is in the vertical orientation. Flowing upward through the exit passage 136, the coolant 140 then flows circumferentially around and downward through the outer passage 134, dissipating heat to the ambient medium 10 surrounding the outer shell 110. The ambient medium 10 may include gas, liquid, and/or a solid surrounding the outer shell, such as ambient air. The downward flow of the coolant 140 through the outer passage 134 may similarly be induced by convective flow of the coolant 140 as energy from the coolant 140 is transferred to the ambient medium 10. In particular, the coolant 140 within the outer passage 134 is positioned distal from the inner cavity 116 as compared to the coolant 140 within the inner passage 132, reducing the amount of heat absorbed by the coolant 140 within the outer passage 134 as compared to the inner passage 132. Further, the outer passage 134 is thermally coupled to the ambient medium 10 surrounding the outer shell 110, such that heat from the coolant 140 is transferred to the ambient medium 10. Alternatively or additionally, the flow of the coolant 140 through the outer passage 134 may be induced, such as with a pump, and the pump may induce flow of the coolant 140 upward or downward in the vertical direction within the outer passage 134. As the coolant 140 cools and flows downward and circumferentially around the outer passage 134, the coolant reaches the bottom of the outer passage 134. The coolant 140 then flows upward through the return passage 138 that is in fluid communication with the inner passage 132 and the outer passage 134. While only a portion of the return passage 138 is shown, it should be understood that the return passage 138 extends along the length 106 (FIG. 8) of the outer shell 110. By including a return passage 138 that extends along the length 106 (FIG. 8) of the outer shell 110, the return passage 138 allows upward flow of the coolant 140 to the inner passage 132 from the outer passage 134 when the outer shell 110 is in the horizontal orientation as shown in FIGS. 11 and 12, as compared to the embodiment shown in FIG. 3B, in which the outer shell 110 is in the vertical orientation. In some embodiments, the fuel storage cask 100 may include an optional wick that is positioned within the return passage 138, the outer passage 134, and/or the inner passage 132 to assist in moving the coolant 140 upward through the return passage 138 toward the inner passage 132. Referring to FIG. 13, a cross-section of the outer shell 110 is depicted showing the flow of the coolant 140 through the cooling circuit 130. As described above, when the outer shell 110 is in a horizontal orientation, the coolant 140 flows upward and circumferentially around the inner passageway 132 toward the exit passage 136, absorbing heat from the inner cavity 116, such as heat energy that may be generated from spent fuel rods positioned within the inner cavity 116. The coolant 140 then moves upward through the exit passage 136 toward the outer passage 134. After passing through the exit passage 136, the coolant 140 flows downward and circumferentially around the outer passage 134, and dissipates heat to the ambient medium 10. After cooling, the coolant 140 reaches the return passage 138 and flows upward back to the inner passage 132 to again absorb heat from the inner cavity 116. The fuel storage cask 100 optionally includes the wick 142 positioned in the outer passage 134, the return passage 138, and/or the inner passage 132, and the wick 142 may assist in moving coolant 140 through the return passage 138 to the inner passage 132. In embodiments, the coolant 140 may include a gas, a liquid, or a gas/liquid mix that absorbs heat from the inner cavity 116. For example, in some embodiments, the coolant 140 includes helium or the like. Referring to FIG. 14, another embodiment of the fuel storage cask 100 is schematically depicted. The fuel storage cask 100 includes the outer shell 110 with a cooling circuit 130, similar to the above-described embodiments. In the embodiment depicted in FIG. 14, a central cooling member 160 extends through the center of the outer shell 110. The central cooling member 160 provides cooling to the center of the inner cavity 116 (FIG. 13). Referring to FIG. 15, the outer shell 110 is shown in hidden lines for clarity. A basket 117 may optionally be positioned within the inner cavity 116, and may assist in aligning and storing spend fuel rods within the inner cavity 116. The central cooling member 160 extends through a center portion 113 of the inner cavity 116 and the central cooling member 160 may assist in dissipating heat from the center portion 113 of the inner cavity 116. As described above and as depicted in the embodiments shown in FIGS. 4 and 13, the cooling circuit 130 includes the inner passage 132 (FIG. 13) which is positioned around the inner perimeter 114, and acts to absorb heat from the inner cavity 116 around the inner perimeter 114. However, since the cooling circuits 130 depicted in FIGS. 4 and 13 extend around the inner perimeter 114 of the inner cavity 116, the cooling circuits 130 may have difficulty absorbing heat from the center portion 113 of the inner cavity 116, as the center portion 113 is positioned radially inward and distal from the inner perimeter 114. However, in the embodiment depicted in FIG. 15, the central cooling member 160 extends through the center portion 113 of the inner cavity 116 and absorbs heat from the center portion 113 of the inner cavity 116. Referring to FIG. 16, the central cooling member 160 is depicted in isolation. The central cooling member 160 includes one or more evaporator passages 162 that are in fluid communication with one or more condenser passages 164, and the coolant 140 is positioned within the evaporator passages 162 and the condenser passages 164. The evaporator passages 162 are thermally coupled to the inner cavity 116 (FIG. 15) of the outer shell 110, such that heat energy, such as may be generated by spent fuel rods positioned within the inner cavity 116, is transmitted to the evaporator passages 162, and more particularly to the coolant 140 positioned within the evaporator passages 162. As the coolant 140 within the evaporator passages 162 absorbs heat energy from the inner cavity 116 (FIG. 15), the coolant 140 flows upward through the evaporator passages 162, and outward to the condenser passages 164. The condenser passages 164 are thermally coupled to the ambient medium 10 (FIG. 15), and heat energy from the coolant 140 within the condenser passages 164 is dissipated to the ambient medium 10. As the coolant 140 within the condenser passages 164 dissipates heat, the coolant 140 cools and flows downward through the condenser passages 164 in the vertical direction, until the coolant reaches the bottom of the condenser passages 164. Upon reaching the bottom of the condenser passages 164, the coolant 140 flows inward toward towards the evaporator passages 162, and again absorbs heat from the inner cavity 116 (FIG. 15). The coolant 140 may move through the evaporator passages 162 and the condenser passages 164 through convective flow of the coolant 140 resulting from the absorption and dissipation of heat energy of the coolant 140. Alternatively or additionally, the flow of the coolant 140 through the evaporator passages 162 and the condenser passages 164 may be induced, such as with a pump, and the pump may induce flow of the coolant 140 upward or downward in the vertical direction within the evaporator passages 162 and the condenser passages 164. The central cooling member 160 may be used in conjunction with the cooling circuit 130 described above and depicted in FIGS. 4 and 11, which may assist in dissipating heat from both the inner perimeter 114 of the inner cavity 116 (FIG. 4), as well the center portion 113 of the inner cavity 116 (FIG. 15). In some embodiments, the evaporator passages 162 and/or the condenser passages 164 of the central cooling member 160 may be in fluid communication with the inner passage 132 and/or the outer passage 134 of the cooling circuit 130 described above and depicted in FIGS. 4 and 13. In other words, the coolant 140 within the central cooling member 160 may be in fluid communication with the coolant 140 within the cooling circuit 130 described above and depicted in FIGS. 4 and 13, such that the central cooling member 160 is integral with the cooling circuit 130. Alternatively, the central cooling member 160 may be separate and/or separable from the cooling circuit 130 (FIGS. 4, 13). In such embodiments, the central cooling member 160 may be in fluid communication with the cooling circuit 130, or may not be in fluid communication with the cooling circuit 130, and may be hermetically sealed, operating independently of the cooling circuit 130 described above and depicted in FIGS. 4 and 13. In some embodiments, the central cooling member 160 operate as a stand-alone cooling member 160, for example, in fuel storage casks that do not include a cooling circuit 130. Accordingly, it should now be understood that fuel storage casks according to the present disclosure include a cooling circuit that dissipates heat from an inner cavity of an outer shell of a fuel storage cask. The cooling circuit may be hermetically sealed and extend around an inner perimeter of the inner cavity of the fuel storage cask. Coolant within the cooling circuit flows through an inner passage that is thermally coupled the inner cavity of the fuel storage cask, and may absorb heat energy from spent fuel rods positioned within the inner cavity. The inner passage may include an annular shape that extends circumferentially around the inner cavity of the fuel storage cask to maximize the surface area of coolant exposed to the heat generated from within the inner cavity, which may assist in maximizing the amount of heat that may be absorbed by the coolant. The coolant flows from the inner passage to an outer passage of the cooling circuit, and the outer passage is thermally coupled to an ambient medium. The outer passage may include an annular shape that extends circumferentially around the outer shell of the fuel storage cask, which may maximize the surface area of coolant exposed to the ambient medium, which may assist in maximizing the amount of heat that may be dissipated to the ambient medium from the coolant. In this way, the cooling circuit forms a “closed loop” circuit for cooling the fuel storage cask that is not exclusively dependent on external airflow over the fuel storage cask to draw heat away from the fuel storage cask. By reducing the dependency on external airflow to cool the fuel storage cask, the cooling circuit may maintain the fuel storage cask at an operable temperature without requiring external vents to direct airflow, which may reduce maintenance and operating costs associated with the fuel storage cask and reduce risk of the fuel storage cask overheating in the instance of an external vent being blocked.
	abstract	Example embodiments are directed to tie plate attachments having irradiation targets and/or fuel assemblies having example embodiment tie plate attachments with irradiation targets and methods of using the same to generate radioisotopes. Example embodiment tie plate attachments may include a plurality of retention bores that permit irradiation targets to be contained in the retention bores. Irradiation targets may be irradiated in an operating nuclear core including the fuel assemblies, generating radioisotopes that may be harvested from the spent nuclear fuel assembly by removing example embodiment tie plate attachments.
	claims	1. A composition comprising an inorganic scintillator comprising an alkali metal hafnate, cerium-doped, having the formula A2HfO3:Ce; wherein the A is Na, and the molar percent of cerium is 0.1% to 90%. 2. The composition of claim 1, wherein the molar percent of cerium is 0.1% to 10%. 3. A composition consisting essentially of a mixture of an alkali metal carbonate, oxide or hydroxide, cerium oxide, and hafnium oxide, wherein the alkali metal is Na, and the molar percent of cerium is from 0.1% to 90%. 4. The composition of claim 3, wherein the mixture consists essentially of solid alkali carbonate, oxide or hydroxide, and solid hafnium oxide, and solid cerium oxide, wherein the mixture has a stoichiometry of about 2 alkali metal atoms: about 1 hafnium atom. 5. The composition of claim 4, wherein (i) the solid alkali metal carbonate, oxide or hydroxide is Na2CO3, and (ii) the cerium oxide is Ce2O3. 6. The composition of claim 4, wherein the solid alkali carbonate, oxide or hydroxide, and solid hafnium oxide, and solid cerium oxide are powdered crystals. 7. The composition of claim 3, wherein the molar percent of cerium is 0.1% to 10%. 8. A method for producing the composition comprising an inorganic scintillator comprising:a. providing the composition of claim 3,b. heating the mixture so that the salts or solids start to react, andc. cooling the mixture of the formed composition to room temperature such that the inorganic scintillator is formed. 9. The method of claim 8, wherein the mixture consists essentially of solid alkali metal carbonate, oxide or hydroxide, and solid hafnium oxide, and solid cerium oxide, wherein the mixture has a stoichiometry of about 2 alkali metal atoms: about 1 hafnium atom. 10. A device comprising the composition of claim 1.
	claims	1. A protection apparatus, comprising:a garment that substantially contours to an operator's body wherein the garment is operable to protect the operator from a substantial portion of radiation;a frame that substantially contours to the operator's body wherein the frame is operable to support the garment separate from the operator and is operable to substantially maintain its substantially contoured shape in the absence of the operator; and,a suspension assembly operable to support the weight of the frame and garment relative to the operator wherein the suspension assembly includes at least one rotatable arm. 2. A protection apparatus, comprising:a garment that substantially contours to an operator's body wherein the garment is operable to protect the operator from a substantial portion of radiation;a frame that substantially contours to the operator's body wherein the frame is operable to support the garment separate from the operator and is operable to substantially maintain its substantially contoured shape in the absence of the operator;a suspension assembly operable to support the weight of the frame and garment relative to the operator; and,at least one holonomic manipulator arm. 3. A protection apparatus, comprising:a garment that substantially contours to an operator's body wherein the garment is operable to protect the operator from a substantial portion of radiation;a frame that substantially contours to the operator's body wherein the frame is operable to support the garment separate from the operator and is operable to substantially maintain its substantially contoured shape in the absence of the operator; and,a suspension assembly operable to support the weight of the frame and garment relative to the operator wherein the frame and suspension assembly are secured together with at least one rotatable pitch axle connection. 4. A protection apparatus, comprising:a garment that substantially contours to an operator's body wherein the garment is operable to protect the operator from a substantial portion of radiation;a frame that substantially contours to the operator's body wherein the frame is operable to support the garment separate from the operator and is operable to substantially maintain its substantially contoured shape in the absence of the operator;a suspension assembly operable to support the weight of the frame and garment relative to the operator wherein the suspension assembly includes a mobile floor stand wherein the floor stand includes means for docking the mobile floor stand to a floor surface. 5. A protection apparatus, comprising:a garment that substantially contours to an operator's body wherein the garment is operable to protect the operator from a substantial portion of radiation;a frame that substantially contours to the operator's body wherein the frame is operable to support the garment separate from the operator and is operable to substantially maintain its substantially contoured shape in the absence of the operator; and,a suspension assembly operable to support the weight of the frame and garment relative to the operator wherein the suspension assembly includes a mobile floor stand wherein the mobile floor stand is integrated with a back table. 6. A protection apparatus, comprising:a garment that substantially contours to an operator's body wherein the garment is operable to protect the operator from a substantial portion of radiation;a frame that substantially contours to the operator's body wherein the frame is operable to support the garment separate from the operator and is operable to substantially maintain its substantially contoured shape in the absence of the operator; and,a suspension assembly operable to support the weight of the frame and garment relative to the operator wherein the suspension assembly includes a mobile floor stand; and,a jib-boom system. 7. A protection apparatus, comprising:a garment that substantially contours to an operator's body wherein the garment is operable to protect the operator from a substantial portion of radiation;a frame that substantially contours to the operator's body wherein the frame is operable to support the garment separate from the operator and is operable to substantially maintain its substantially contoured shape in the absence of the operator;a suspension assembly operable to support the weight of the frame and garment relative to the operator;a portable track stand or table upon which the suspension assembly is attached; and,a floor hook for stabilizing the portable track stand or table. 8. A method, comprising:suspending with a suspension assembly a radiation protection system which includes a garment and a face shield secured to a frame operable to protect an operator from a substantial portion of radiation, wherein the radiation protection system includes a joint in substantial proximity of the center of gravity of the radiation protection system allowing motion in at least one degree of freedom, wherein the frame and suspension assembly are secured together with at least one rotatable pitch axle connection;contouring a portion of the frame to the operator's body; and,engaging the operator with the protection system. 9. A method, comprising:suspending with a suspension assembly a radiation protection system which includes a garment and a face shield secured to a frame operable to protect an operator from a substantial portion of radiation wherein the suspension assembly is detachably connected to a mobile floor stand integrated with a medical operations back-table;contouring a portion of the frame to the operator's body; and,engaging the operator with the protection system. 10. A method, comprising:suspending with a suspension assembly a radiation protection system which includes a garment and a face shield secured to a frame operable to protect an operator from a substantial portion of radiation wherein the suspension assembly is detachably connected to a mobile floor stand wherein the mobile floor stand is detachably secured to a floor;contouring a portion of the frame to the operator's body; and,engaging the operator with the protection system. 11. A method, comprising:suspending with a suspension assembly a radiation protection system which includes a garment and a face shield secured to a frame operable to protect an operator from a substantial portion of radiation wherein the suspension assembly is detachably connected to a mobile floor stand wherein the mobile floor stand is detachably secured to a ceiling;contouring a portion of the frame to the operator's body; and,engaging the operator with the protection system.
	description	1. Field Example embodiments generally relate to fuel structures and materials used in nuclear power plants. 2. Description of Related Art Generally, nuclear power plants include a reactor core having fuel arranged therein to produce power by nuclear fission. A common design in nuclear power plants is to arrange fuel in a plurality of fuel rods bound together as a fuel assembly, or fuel bundle, placed within the reactor core. These fuel rods typically include several elements joining the fuel rods to assembly components at various axial locations throughout the assembly. As shown in FIG. 1, a conventional fuel bundle 10 of a nuclear reactor, such as a boiling water reactor (BWR), may include an outer channel 12 surrounding an upper tie plate 14 and a lower tie plate 16. A plurality of full-length fuel rods 18 and/or part length fuel rods 19 may be arranged in a matrix within the fuel bundle 10 and pass through a plurality of spacers 15. Fuel rods 18 and 19 generally originate and terminate at the same vertical position, all rods continuously running the length of the fuel bundle 10, with the exception of part length rods 19, which all terminate at a lower vertical position from the full length rods 18. An upper end plug 20 and/or lower end plug 30 may join the fuel rods 18 and 19 to the upper and lower tie plates 14 and 16, with only the lower end plug 30 being used in the case of part length rods 19. As shown in FIGS. 2A and 2B, conventional upper and lower tie plates 14 and 16 may be generally solid and flat. A plurality of holes, called bosses, 25 may receive lower end plugs of all rods in an assembly in the lower tie plate 16. Similarly, a plurality of bosses 25 may receive the upper end plugs of all full-length rods in the upper tie plate 14. Part length rods may not terminate at a tie plate. In this way, upper and lower tie plates 14 and 16 may axially join fuel rods to the fuel assembly and hold fuel rods at a constant and shared axial displacement in the core. Because bosses and corresponding fuel rods may begin and/or terminate at the same axial position within the bundle, fluid flow may be restricted at these axial positions. A continuing problem during operation of a nuclear reactor is the existence of debris of various sizes. Examples of such debris may include small-sized fasteners, metal clips, welding slag, pieces of wire, etc. The debris may be generated as a result of the original construction of the reactor core, subsequent reactor operation and/or due to repairs made during a planned or unplanned maintenance outage. Current fuel designs do not prevent particulate debris from entering the top of the fuel bundle. As work is performed during outages, there is the possibility that debris can enter the top of the fuel bundles and cause a fuel failure. Example embodiments are directed to upper tie plates for debris mitigation. Example embodiment upper tie plates may have a plurality of debris capture elements above the plurality of bosses and configured to overlap each other. In this way, the plurality of debris capture elements may prevent or reduce debris from entering the top of a fuel bundle. Example embodiment fuel bundles may use upper tie plates including the plurality of debris capture elements such that particulate debris is prevented or reduced from continually falling into a fuel bundle below and cause failed fuel rods. Detailed illustrative example embodiments are disclosed herein. However, specific structural and functional details disclosed herein are merely representative for purposes of describing example embodiments. The example embodiments may, however, be embodied in many alternate forms and should not be construed as limited to only example embodiments set forth herein. It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. It will be understood that when an element is referred to as being “connected,” “coupled,” “mated,” “attached,” or “fixed” to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between”, “adjacent” versus “directly adjacent”, etc.). The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the language explicitly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes,” and/or “including,” when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. It should also be noted that in some alternative implementations, the functions/acts noted may occur out of the order noted in the figures. For example, two figures shown in succession may in fact be executed substantially concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved. FIG. 3 is an isometric view of an example embodiment debris mitigation upper tie plate. As shown in FIG. 3, an example embodiment upper tie plate 100 includes a body 110 having a plurality of bosses 115 therein. Some of the plurality of bosses 117 may be longer in length than the other bosses 116. A plurality of debris capture elements 120 are formed on or connected to the plurality of bosses 117 or formed on the handle 140 of the upper tie plate 100. The plurality of debris capture elements 120 may overlap each other so as to create debris traps for particulate debris that would fall onto the fuel bundle. The plurality of debris capture elements 120 may take on a variety of configurations. For example, the plurality of debris capture elements 120 may be one of troughs, conical features and/or any other shape that captures debris. The plurality of debris capture elements 120 may be at an angle with respect to a vertical direction to allow the debris to collect at one end and may be at different heights above the plurality of bosses 117. Sides of the debris capture elements 120 may be one of a triangular, rectangular, trapezoidal, and/or some other irregular shape. At least two of the plurality of debris capture elements 120 are offset from one another by a flow area 130 between the plurality of debris capture elements 120, which minimizes or reduces the resulting pressure drop caused by the debris capture elements 120. The plurality of debris capture elements 120 may be integral with the upper tie plate 100 or may be coupled together in a separate assembly mounted on top of the upper tie plate 100. The above-described configuration of the plurality of debris capture elements 120 according to example embodiments allows for the falling debris to collect within. As such, the debris capture elements 120 may prevent or reduce particulate debris from continually falling into a fuel bundle below (not shown), thereby causing failed fuel rods. FIG. 4 is a side view of the example embodiment debris mitigation upper tie plate 100 as illustrated in FIG. 3. As can be seen in FIG. 4, the plurality of debris capture elements 120 may be staggered along the y-axis. At least one of the plurality of debris capture elements 120 may be positioned at a height H1 along the y-axis. At least another one of the plurality of debris capture elements 120 may be positioned at a height H2, which is greater than the height H1, along the y-axis. FIG. 5 is a plan view of the example embodiment debris mitigation upper tie plate 100 as illustrated in FIG. 3. As can be seen in FIG. 5, the plurality of debris capture elements 120 may overlap each other and the handle 140 completely so as to create debris traps for particulate debris that would fall onto the bundle. FIG. 6 is an illustration of a fuel assembly including the debris mitigation upper tie plate of an example embodiment. As shown in FIG. 6, a fuel bundle 1000 of a nuclear reactor may include an outer channel 102 surrounding an upper tie plate 100 according to an example embodiment and a lower tie plate 106. A plurality of full-length fuel rods 108 and/or part length fuel rods 109 may be arranged in a matrix within the fuel bundle 1000 and pass through a plurality of spacers 105. Fuel rods 108 and 109 generally originate and terminate at the same vertical position, all rods continuously running the length of the fuel bundle 1000, with the exception of part length rods 109, which all terminate at a lower vertical position from the full length rods 108. An example embodiment upper tie plate 100 includes a body 110 having a plurality of bosses 115 therein. Some of the plurality of bosses 117 may be longer in length than the other bosses 116. A plurality of debris capture elements 120 are formed on or connected to the plurality of bosses 117 or formed on the handle 140 of the upper tie plate 100. The plurality of debris capture elements 120 may overlap each other so as to create debris traps for particulate debris that would fall onto the fuel bundle. At least two of the plurality of debris capture elements 120 are offset from one another by a flow area 130 between the plurality of debris capture elements 120, which minimizes or reduces the resulting pressure drop caused by the debris capture elements 120. As described above, an example embodiment of a debris mitigation upper tie plate includes a plurality of debris capture elements that allow for the falling debris to collect within. As such, the plurality of debris capture elements may prevent or reduce particulate debris from falling and damaging the fuel rods of a fuel bundle. Example embodiments thus being described, it will be appreciated by one skilled in the art that example embodiments may be varied through routine experimentation and without further inventive activity. For example, other fuel types, shapes, and configurations may be used in conjunction with example embodiment fuel bundles and tiered tie plates. Variations are not to be regarded as departure from the spirit and scope of the exemplary embodiments, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.
052079805	description	DETAILED DESCRIPTION OF THE INVENTION In the following description, like references characters designate like or corresponding parts throughout the several views. Also in the following description, it is to be understood that such terms as "forward", "rearward", "left", "right", "upwardly", "downwardly", and the like, are words of convenience and are not to be construed as limiting terms. In General Referring now to the drawings, and particularly to FIG. 1, there is shown a prior art nuclear fuel assembly, generally designated 10. Being the type use in a pressurized water nuclear reactor (PWR), the prior art fuel assembly 10 basically includes a lower end structure or bottom nozzle 12 for supporting the assembly on the lower core plate (not shown) in the core region of a reactor (not shown), and a number of longitudinally extending guide tubes or thimbles 14 which project upwardly from the bottom nozzle 12. The assembly 10 further includes a plurality of transverse grids 16 axially spaced along the guide thimbles 14 and an organized array of elongated fuel rods 18 transversely spaced and supported by the grids 16. Also, the assembly 10 has an instrumentation tube 20 located in the center thereof and an upper end structure or top nozzle 22 attached to the upper ends of the guide thimbles 14. With such an arrangement of parts, the fuel assembly 10 forms an integral unit capable of being conventionally handled without damaging the assembly parts. As mentioned above, the fuel rods 18 in the array thereof in the assembly 10 are held in spaced relationship with one another by the grids 16 spaced along the fuel assembly length. Each fuel rod 18 includes nuclear fuel pellets 24 and the opposite ends of the rod are closed by upper and lower end plugs 26, 28 to hermetically seal the rod. Commonly, a plenum spring 30 is disposed between the upper end plug 26 and the pellets 24 to maintain the pellets in a tight, stacked relationship within the rod 18. The fuel pellets 24 composed of fissile material are responsible for creating the reactive power of the nuclear reactor. A liquid moderator/coolant such as water, or water containing boron, is pumped upwardly through the fuel assemblies of the core in order to extract heat generated therein for the production of useful work. To control the fission process, a number of control rods 32 are reciprocally movable in the guide thimbles 14 located at predetermined positions in the fuel assembly 10. Specifically, the top nozzle 22 includes a rod cluster control mechanism 34 having an internally grooved cylindrical member 36 with a plurality of radially extending flukes or arms 38. Each arm 38 is interconnected to a control rod 32 such that the control mechanism 34 is operable to move the control rods 32 vertically in the guide thimbles 14 to thereby control the fission process in the fuel assembly 10, all in a well-known manner. Referring now to FIGS. 2 and 3 as well as FIG. 1, it can be seen that the art top nozzle 22 of the prior art fuel assembly 10 includes an enclosure or housing 40 formed by a transversely extending lower adapter plate 42 and an upper annular flange 44 with an upstanding sidewall 46 extending between and integrally interconnecting the adapter plate 42 and flange 44 at their respective peripheries. The lower adapter plate 42 has a main central portion 42A provided with a first plurality of holes 48 to permit the flow of coolant upward through the top nozzle 22 and a second plurality of holes 50 to receive the upper ends of the guide thimbles 14 and where they are attached to the lower adapter plate 42. The upper annular flange 44 defines a central top opening 52 in the top nozzle 22 through which is disposed the rod cluster control assembly 34 being operable to insert and withdraw the control rods 32 into and from the guide thimbles 14 of the fuel assembly 10 through the second plurality of lower adapter plate holes 50. Also, a plurality of spring assemblies 54 are suitably clamped to the upper annular flange 44 to constitute a hold-down device for the fuel assembly 10. Each spring assembly 54 is composed of a set of leaf springs 54A disposed in a stack relation, and fastened in operative position on the top nozzle upper flange 44 at each of one pair of opposite diagonal corners 22A of the top nozzle 22 by using a spring clamp 56 which includes a corner block 58 and a spring screw 60. The spring assemblies 54 cooperate in a conventional manner with an upper core plate 62 of the reactor core located above the fuel assembly 10 to prevent hydraulic lifting of the fuel assembly 10 caused by upward coolant flow while allowing for changes in fuel assembly length due to core induced thermal expansion and the like. Prior Art Guide Pins Referring to FIGS. 1 and 4-7, there is illustrated a first embodiment of a guide pin of the prior art, generally designated 64, mounted from the upper core plate 62. The other pair of diagonal corners 22B of the top nozzle 22 of FIGS. 2 and 3 have upwardly projecting abutments 66 formed on the upper annular flange 44 and defining holes 68 which mate with the prior art guide pins 64 mounted in and projecting below the upper core plate 62. The guide pins 64 disposed between the upper core plate 62 and top nozzle 22 of each fuel assembly 10 provide proper alignment and engagement of the fuel assembly 10 with the upper core plate 62 so that the guide thimbles 14 of the fuel assembly 10 will extend vertically in alignment with the control rods 32 for receiving the control rods 32 from above. Referring to FIGS. 4-7, the first embodiment of the prior art guide pin 64 has a generally circular crosssection, and includes an elongated lower body portion 64A with a conical or bullet-shaped lower end nose 64B, a threaded upper end portion 64C, and an upper shaft portion 64D of reduced diameter which interconnects the lower body portion 64A and the threaded upper end portion 64C. The upper shaft portion 64D has a smaller diameter than the lower body portion 64A so as to facilitate a tight fitting (shrink fit) relation with the upper core plate 62 through a bore 70 in the upper core plate 62, with an upwardly-facing annular shoulder 64E defined on the upper end of the lower body portion 64A abutting against a lower surface 62A of the upper core plate 62 about the bore 70. Also, the upper core plate 62 has a recess 72 defined in an upper surface 62B which receives an attachment nut 74. The nut 74 has an internally-threaded central hole 76 by which it is threaded onto the threaded upper end portion 64C of the guide pin 64. The attachment nut 74 also has a pair of pilot holes 78 offset from opposite sides of the central hole 76 which mate with alignment pins on a tool (not shown) used in threading the nut 74 on the upper end portion 64C of the guide pin 64. To install the guide pin 64, the nut 74 is tightened relative to the bottom of the upper core plate recess 72 to thereby clamp the upper core plate 62 between the nut 74 and the shoulder 64E on the lower body portion 64A of the guide pin 64. After installation, the attachment nut 74 is permanently attached, such as by tack welding, to the upper core plate 62. Referring to FIGS. 8-10, there is illustrated a second embodiment of a guide pin of the prior art, generally designated 80, mounted from the top nozzle 22. The second embodiment of the prior art guide pin 80 has a generally circular cross-section, and includes an elongated upper body portion 80A with a conical or bullet-shaped upper end nose 80B, a threaded lower end portion 80C, and a lower shaft portion 80D of reduced diameter which interconnects the upper body portion 80A and the threaded lower end portion 80C. The lower shaft portion 80D has a smaller diameter than the upper body portion 80A so as to facilitate installation of the guide pin 80 in the hole 68 of one of the top nozzle corner raised abutments 66. At its end, the upper body portion 80A an enlarged diameter collar 80E integrally formed thereabout which rests on the top surface 66A of the abutment 66 extending about the hole 68 therein. The threaded lower end portion 80C of the guide pin 80 is threaded into the internally threaded abutment hole 68 and thereafter a lock pin 82 is driven into a hole 84 drilled radially through the abutment 66 and into the lower shaft portion 80D, as seen in FIG. 8. From the above descriptions, it will be understood that the first and second embodiments of the prior art guide pins 64, 80 are intended to be permanently attached the respective upper core plate 62 and top nozzle 22. Guide Pin Assemblies of the Invention Turning now to FIGS. 11-29, there is illustrated a first embodiment of a replacement (and removable) guide pin assembly in accordance with the present invention, being generally designated 86, for installation in one of the corner abutment holes 68 of the top nozzle 22. The first embodiment of the replacement guide pin assembly 86 includes an elongated guide pin body 88, a ferrule 90, a lock screw 92, and a lock pin 94. Referring to FIGS. 11-14, the guide pin body 88 of the replacement guide pin assembly 86 has a bullet-shaped upper end nose 88A, a lower expandable base 88B, and an elongated middle cylindrical shaft portion 88C of generally uniform or constant diameter extending between and integrally connected with the upper end nose 88A and lower expansion base 88B. The bullet-shaped nose 88A facilitates insertion of the middle shaft portion 88C of the guide pin body 88 into the bore 70 of the upper core plate 62 which is the same bore used in case of the prior art guide pins. The middle cylindrical shaft portion 88C of the guide pin body 88 will extend within the bore 70 and thereby interface with the upper core plate 62. An annular flange 96 is formed on the guide pin body 88 at the juncture of the lower expansion base 88B and the middle shaft portion 88C thereof. The annular flange 96 projects radially outwardly from the guide pin body 88 and has a downwardly-facing, outwardly and upwardly inclined, shoulder 96A which seats on a complementarily-shaped internal annular surface 98 defined in the top surface 66A of the top nozzle abutment 66 surrounding the upper end of the abutment hole 68. The surface 98 provides a reference elevation for the guide pin assembly 86. The lower expandable base 88B of the guide pin body 88 has an upper cylindrical base portion 100, a lower cylindrical thin-walled skirt portion 102, and a middle expandable wall portion 104, which portions extend within the top nozzle abutment bore 68, thereby interfacing with the top nozzle 22. The upper base portion 100 of the lower expandable base 88B has a central internally-threaded bore 100A. The middle expandable wall portion 104 has a plurality of circumferentially spaced vertical slots 106 defining between them a plurality of flexible wall segments 108 extending between and interconnecting the upper base portion 100 and the lower skirt portion 102. The interior surfaces 108A of the wall segments 108 are inclined upwardly and inwardly with respect to a longitudinal axis A of the guide pin body 88. Referring to FIGS. 11-20, the ferrule 90 and lock screw 92 of the replacement guide pin assembly 86 interfit within the lower expandable base 88B of the guide pin body 88. The ferrule 90 has a central opening 90A and a frusto-conical exterior configuration defining an exterior surface 90B inclined upwardly and inwardly relative to the longitudinal axis A of the guide pin body 88. The exterior surface 90B of the ferrule 90 is thus complementary to and interfaced with the interior surfaces 108A of the wall segments 108 of the lower expandable base 88B. The ferrule 90 is installed into the interior of the lower expandable base 88B of the guide pin body 88 from its lower end and upwardly along the longitudinal axis A of the guide pin body 88. The ferrule 90 thus interfits with the lower expandable base 88B of the guide pin body 88 and is capable of imparting a radially and outwardly directed force on the lower expandable base 88B to expand of the base within the hole 68 of the top nozzle 22 and thereby to secure the guide pin body 88 to the top nozzle 22 in response to a predetermined displacement of the ferrule 90 relative to the guide pin body 88 along its longitudinal axis A. The lock screw 92 has cylindrical shank 92A and head 92B integrally attached to the lower end of the shank 92A. The upper portion of the shank 92A has a reduced diameter (or relief) section 92C (compared to the rest of the shank) which defines an annular stop 92D on the top end of the shank 92A. The shank 92A and stop 92D fit upwardly through the central opening 90A of the ferrule 90 (once the latter has already been installed in the lower expandable base 88B) and into the internally-threaded bore 100A in the upper base portion 100 of the lower expandable base 88B. A portion 92E of the shank 92A immediately below the reduced diameter section 92C is externally-threaded to allow threading of the lock screw 92 into the guide pin body 88. The lock screw 92 thus provides a means which interfits with the ferrule 90 and threads into the guide pin body 88 to produce the required predetermined displacement of the ferrule 90 to cause expanding of the lower expandable base 88B. Referring to FIGS. 21-25, the purpose of the reduced diameter section 92C on the shank 92A, which defines an annular cavity 110 between the shank 92A and the upper base portion 100, is to accommodate the presence of the lock pin 94 in order to hold the guide pin body 88, ferrule 90, and lock screw 92 together as a unit before installation in the abutment hole 68 in the top nozzle 22. The lock pin 94 will thus preclude the lock screw 92 from being unthreaded and withdrawn inadvertently from the guide pin body 88 which would result in the ferrule 90 and lock screw 92 becoming loose parts. The lock pin 94 is forced into a hole 112 predrilled through the upper base portion 100 of the lower expandable base 88B of the guide pin body 88. The hole 112 is predrilled generally perpendicular to and offset from the longitudinal axis A of the guide pin body 88 so as not to intersect with the reduced diameter section 92C on the shank 92A and instead intersect with the annular cavity 110. Thus, the lock pin 94 when installed through the hole 112 will underlie the annular stop 92D on the top end of the shank 92A so as to prevent removal of the lock screw 92 without first removing the lock pin 94. Referring to FIGS. 26-29, there is illustrated the first embodiment of the replacement guide pin assembly 86 of the present invention at successive stages of the procedure for installing the guide pin assembly 86 in the top nozzle 22. FIG. 26 shows guide pin assembly 86 before insertion into one of the corner abutment holes 68 of the top nozzle 22. It will be observed that the lock pin 94 has been installed so as to hold the guide pin body 88, ferrule 90, and lock screw 92 together as a unit. FIG. 27 depicts the guide pin assembly 86 after insertion in the corner abutment hole 68 of the top nozzle 22, but before final torquing or tightening of the lock screw 92 into the guide pin body 88 and crimping of a lower peripheral edge 102A of the lower skirt portion 102 of the lower expandable base 88B under the outer peripheral edge 92F of the lower head 92B of the lock screw 92. It will be noted that a small gap 114 exists between the top of the ferrule 90 and the upper base portion 100 of the lower expandable base 88B of the guide pin body 88. The width of this gap 114 represents the amount of predetermined displacement that the ferrule 90 must undergo in order to impart the required radially and outwardly directed force to expand the lower expandable base 88B the desired amount to secure the guide pin body 88 in the top nozzle hole 68. FIGS. 28 and 29 show the guide pin assembly 86 after torquing of the lock screw 92 completely into the guide pin body 88 and crimping of the lower peripheral edge 102A of the lower skirt portion 102 of the lower expandable base 88B under the outer peripheral edge 92F of the lock screw lower head 92B. To torque the lock screw 92, a socket 116 for receiving an appropriate tool (not shown) is provided in the lower surface of the head 92B. During threading and torquing of the lock screw 92 into the guide pin body 88, the ferrule 90 is displaced the desired predetermined amount along the longitudinal axis A of the guide pin body 88 such that the forementioned gap 114 between the ferrule 90 and guide pin body 88 becomes closed. The purpose of the gap 114 is to provide a predetermined interference fit between the guide pin assembly 86 and the top nozzle 22. As the gap 114 becomes closed by the upward displacement of the ferrule 90, the sliding contact between the complementary inclined surfaces 108A, 90B of the wall segments 108 and the ferrule 90 imparts a radially and outwardly directed force on the slotted flexible wall segments 108 of the middle expandable wall portion 104 of the lower expandable base 88B sufficient to cause them to expand outwardly into engagement with the interior surface of the abutment opening 68 in the top nozzle 22. In such manner the replacement guide pin assembly 86 is secured by an interference fit to the top nozzle 22. As seen in FIG. 29, the lock screw head 92B has a plurality of hemispherical-shaped relief pockets 92G formed in spaced circumferential relation from one another about the peripheral edge 92F of the head 92B. The lower peripheral edge 102A is crimped into the more readily accessible ones of relief pockets 92G. The function of the relief pockets 92G and the crimping of the skirt edge 102A into some of them is to prevent loosening of the lock screw 92 during normal service. Should it be desirable to remove the guide pin assembly 86, a reverse torque can be applied by the socket tool to overpower the skirt crimp and loosen the lock screw 92. Referring to FIGS. 30-39, there is illustrate a second embodiment of a replacement (and removable) guide pin assembly in accordance with the present invention, being generally designated 118, for installation in one of the corner abutment holes 68 of the top nozzle 22. The second embodiment of the replacement guide pin assembly 118 includes an elongated guide pin body 120, an expandable insert 122, a ferrule 124, and an end cap 124. Referring to FIGS. 30-32, the guide pin body 120 of the replacement guide pin assembly 118 has a bullet-shaped upper end nose 120A, a lower attachment base 120B, and an elongated middle cylindrical shaft portion 120C of generally uniform or constant diameter extending between and integrally connected with the upper end nose 120A and lower attachment base 120B. The bullet-shaped nose 120A facilitates insertion of the middle shaft portion 120C of the guide pin body 120 into the bore 70 of the upper core plate 62 which is the same bore used in case of the prior art guide pins. The middle shaft portion 120C of the guide pin body 120 extends within the bore 70, thereby interfacing with the upper core plate 62. The lower attachment base 120B has upper and lower cylindrical mounting sections 128, 130 and a middle mounting section 132 being externally threaded to threadably receive the ferrule 124 as described below. The upper, middle and lower mounting sections 128, 132, 130 are of reduced diameters relative to the middle shaft portion 120C and relative to one another in that order. Referring to FIGS. 30 and 33-35, the expandable insert 122 of the guide pin assembly 118 has an upper cylindrical base portion 134, a lower cylindrical skirt portion 136, and a middle expandable wall portion 138, which portions extend through the top nozzle abutment bore 68 and thereby interface with the top nozzle 22. The expandable insert 122 inserts within the top nozzle hole 68, interfits about the lower attachment base 120B of the guide pin body 120, and is capable of expanding radially outwardly relative to the longitudinal axis A of the guide pin body 120 to provide an interference fit with the top nozzle 22. The upper base portion 134 has a central bore 134A which receives the upper mounting section 128 of the lower attachment base 120A of the guide pin body 120. The middle expandable wall portion 138 has a plurality of circumferentially spaced vertical slots 140 defining between them a plurality of flexible wall segments 142 extending between and interconnecting the upper base portion 134 and the lower skirt portion 136. The interior surfaces 142A of the wall segments 142 are inclined upwardly and inwardly with respect to a longitudinal axis B of the guide pin body 120. An annular flange 144 is formed about the upper peripheral edge of the upper base portion 134 of the expandable insert 122. The annular flange 144 projects radially outwardly from the expandable insert upper base portion 134 and has a downwardly-facing, outwardly and upwardly inclined, shoulder 144A which seats on the complementarily-shaped internal annular surface 98 defined in the top surface 66A of the top nozzle abutment 66 surrounding the upper end of the abutment hole 68. As before, the surface 98 provides a reference elevation for the guide pin assembly 118. Referring to FIGS. 30, 33 and 36-39, the ferrule 124 and end cap 126 of the replacement guide pin assembly 118 fit within the middle wall portion 138 and lower skirt portion 136 of the expandable insert 122 and fit on the middle threaded section 132 and lower section 128 of the lower attachment base 120B of the guide pin body 120. The ferrule 124 has a central opening 124A that is internally-threaded for threading of the ferrule 124 onto the externally-threaded middle section 132 of the lower attachment base 120B of the guide pin body 120. The ferrule 124 also has a frusto-conical exterior configuration defining an exterior surface 124B inclined upwardly and inwardly relative to the longitudinal axis B of the guide pin body 120. The exterior surface 124B of the ferrule 124 is thus complementary to and interfaced with the interior surfaces 142A of the wall segments 142 of the expandable insert 122. The ferrule 124 is installed into the interior of the expandable insert 122 from its lower end and upwardly along the longitudinal axis B of the guide pin body 120. The ferrule 124 interfits with the expandable insert 122 and threads over the middle shaft portion 120C of the guide pin body 120. The ferrule 124, as it is threaded through a predetermined displacement along the longitudinal axis B of the guide pin body 120 toward the upper base portion 134 of the expandable insert 122, will impart a radially and outwardly directed force on the middle expandable wall portion 138 of the expandable insert 122 to expand it within the hole 68 into an interference fit with the top nozzle 22 and thereby to secure the guide pin body 120 to the top nozzle 22. Thus, it is the threading of the ferrule 124 itself on the lower attachment base 120B of the guide pin body 120 which produces the required predetermined displacement of the ferrule 90 to cause expanding of the expandable insert 122. In addition, the ferrule 124 has a plurality of radially outward projecting tabs 124C formed on the exterior surface 124B of the ferrule which are spaced circumferentially from one another. The tabs 124C project into the slots 140 in the expandable middle wall portion 138 of the expandable insert 122 so as to prevent rotation of the ferrule 124 relative thereto as the guide pin body 120 is threaded and torqued into the ferrule 124. The end cap 126 inserts over the lower section 130 of the lower attachment base 120B of the guide pin body 120. The end cap 126 is then attached thereto, such as by tack welding, to preclude disassembly of the basic parts of the guide pin assembly 118 from one another. As in the case of the first embodiment, it will be noted that prior to torquing of the guide pin body 120 to the ferrule 124, a small gap 145 (see FIG. 30) exists between the top of the ferrule 124 and the upper base portion 134 of the expandable insert 122. During torquing, the aforementioned gap 145 between them. The width of this gap 145 becomes closed represents the amount of predetermined displacement that the ferrule 124 must undergo in order to impart the required radially and outwardly directed force to expand the expandable insert 122 the desired amount to secure the guide pin body 120 in the top nozzle hole 68. During threading and torquing of the ferrule 124 onto the lower attachment base 120B of the guide pin body 120, the ferrule 124 is displaced the desired predetermined amount along the longitudinal axis B of the guide pin body 120 such that the forementioned gap 145 between the ferrule 124 and expandable insert 122 becomes closed. The purpose of the gap 145 is to provide a predetermined interference fit between the guide pin assembly 118 and the top nozzle 22. As the gap 145 becomes closed by the upward displacement of the ferrule 124, the sliding contact between the complementary inclined surfaces 142A, 124B of the wall segments 142 and the ferrule 124 imparts a radially and outwardly directed force on the slotted flexible wall segments 142 of the middle expandable wall portion 138 of the expandable insert 122 sufficient to cause them to expand outwardly into engagement with the interior surface of the abutment opening 68 in the top nozzle 22. In such manner the replacement guide pin assembly 118 is secured by an interference fit to the top nozzle 22. Referring to FIGS. 30-32, in order to torque the guide pin body 120 relative to the ferrule 124, the guide pin body 120 has a plurality of torque grooves 146 near the base of its middle shaft portion 120C to accommodate suitable installation tooling (not shown). During torquing of the guide pin body 120, the ferrule 124, in addition to causing expansion of the wall segments 142 into engagement with the top nozzle 22, also acts like a "nut" since it does not rotate due to the presence of the anti-rotation tabs 124C. Also, a locking ring or disc 148 is attached to the guide pin body 120 at the juncture of the middle shaft portion 120C and the lower attachment base 120B. To preclude inadvertent loosening of the parts of the guide pin assembly 118 during reactor operation, the locking ring 148 is crimped locally (at two or three locations) into hemispherical relief pockets 150 provided in the top surface 122A of the expansion insert 122. The guide pin assemblies 86,118, being designed to preclude loose parts, can be installed remotely underwater on irradiated top nozzles. However, because of the evolution of fuel assembly design, most reactors are now operating with cores having fuel assemblies with both welded and removable top nozzles. Should a reactor experience damaged guide pins at a fuel assembly with a removable top nozzle, the irradiated nozzle could be removed and replaced with a top nozzle having these replacement guide pin assemblies 86, 118. Installation of the replacement guide pin assemblies 86, 118 in the new top nozzle could be accomplished in either the factory or field. Equipment and procedures used for fuel assembly top nozzle reconstitution can be readily applied for this repair. To accommodate the replacement guide pin assemblies 86, 118 removal of the damaged guide pin (in its entirety) from the reactor internals upper core plate is necessary. Removal of the guide pin can be readily accomplished by machining out the center of the shank (by either conventional or EDM techniques). Machining out the center of the shank will diminish the pre-load contact stress and facilitate removal of the damaged guide pin. The design of the replacement guide pin body can be specified to maintain fuel assembly top nozzle/upper internals alignment equivalent to that of the original equipment. It is thought that the present invention and many of its attendant advantages will be understood from the foregoing description and it will be apparent that various changes may be made in the form, construction and arrangement thereof without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbefore described being merely a preferred or exemplary embodiment thereof.
060752505	abstract	A radiation image storage panel has a composite composed of a transparent support and a stimulable phosphor layer, and a protective film is provided both on the surface of the phosphor layer side of the composite and on the back surface of the support. The scratch resistance of the protective film is higher than that of the surface of the support and the contact angle of the protective film is larger than that of the surface of the support. The protective film on the support side surface can comprise a fluororesin and light-scattering particles, and further a titanate- or aluminate-coupling agent.
	summary
	abstract	A hazardous material storage repository includes a drillhole extending into the Earth and including an entry. The drillhole includes a vertical drillhole portion, a transition drillhole portion coupled to the vertical drillhole portion, and a hazardous material storage drillhole portion coupled to the transition drillhole portion. The hazardous material storage drillhole portion is located below a self-healing geological formation and is vertically isolated, by the self-healing geological formation, from a zone that comprises mobile water. The repository includes a storage canister positioned in the hazardous material storage drillhole portion and sized to fit from the drillhole entry through the vertical drillhole portion, the transition drillhole portion, and into the hazardous material storage drillhole portion. The storage canister includes an inner cavity sized to enclose hazardous material.
	summary
	summary
	abstract	A method of replacing a damaged thermal sleeve in a reactor vessel head adapter that connects a control rod drive mechanism to a reactor vessel head includes the steps of accessing the damaged thermal sleeve, removing the damaged thermal sleeve, and obtaining a replacement thermal sleeve having an elongated tubular body, a flanged region, and a plurality of slots defined in the elongated tubular body, each slot having a width which is sufficient to narrow a maximum outside diameter of the flanged region from a first diameter to a second diameter. The method further includes altering the maximum outside diameter of the flanged region on the replacement thermal sleeve, inserting the replacement thermal sleeve into an opening of a tubular member from an underside of the reactor vessel head, and expanding the maximum outside diameter of the flanged region into a recess of the reactor vessel head adapter.
	abstract	The invention relates to an X-ray examination apparatus which includes an X-ray source, an X-ray detector, absorption means arranged between the X-ray source and the X-ray detector, a control unit for adjusting the absorption degree of the absorption means, an image processing unit and a display unit. In order to perform an automatic adjustment of the absorption means, the absorption degree therein is optimized in dependence on user-specific parameters (r) and/or apparatus-specific parameters (s) and/or structure parameters (C) and/or parameters (r) classifying the subject matter of the image.
	claims	1. An x-ray generation apparatus comprising: a first tubular member having an inner passage and an outer surface, the outer surface having over at least a portion of the surface an x-ray emitting material responsive to electron bombardment to emit x-ray radiation; and a second tubular member surrounding the first tubular member in a substantially concentric relationship thereto, there being a cavity between the first and second tubular members, the second tubular member having an inner surface facing the outer surface of the first tubular member wherein the inner surface comprises over at least a portion thereof an electron emitter element. 2. The x-ray generation apparatus according to claim 1, wherein an acceleration field is maintained between the electron emitter element and the outer surface of the first tubular member. 3. The x-ray generation apparatus according to claim 2, wherein electrons emitted from the electron emitter element accelerate toward the outer surface of the first tubular member, strike the x-ray emitting material thereon, and thereby cause the emission of x-ray radiation. 4. The x-ray generation apparatus according to claim 3, wherein at least a portion of the emitted x-ray radiation enters the inner passage of the first tubular member. 5. The x-ray generation apparatus according to claim 1, wherein the electron emitter element is a gated electron emitter. 6. The x-ray generation apparatus according to claim 1, wherein the electron emitter element is a thermonic electron emitter. 7. The x-ray generation apparatus according to claim 1, wherein the outer surface of the first tubular member and the inner surface of the second tubular member define a cavity, and wherein the cavity is sealed and is evacuated to less than ambient pressure. 8. The x-ray generation apparatus according to claim 7, wherein the cavity is evacuated to a pressure of less than 10−5 torr. 9. The x-ray generation apparatus according to claim 1, wherein at least one of the first and second tubular members has a substantially smooth cross-section. 10. The x-ray generation apparatus according to claim 1, wherein at least one of the first and second tubular members has a non-smooth cross-section. 11. The x-ray generation apparatus according to claim 1, wherein at least one of the first and second tubular members has a substantially circular cross-section. 12. The x-ray generation apparatus according to claim 1, wherein at least one of the first and second tubular members has a polygonal cross-section. 13. The x-ray generation apparatus according to claim 1, further comprising one or more insulating spacers within the cavity between the first and second tubular members, such that the spacers maintain the first and second tubular members in a nonconductive arrangement with respect to one another. 14. The x-ray generation apparatus according to claim 1, wherein the second tubular member is substantially opaque to x-ray radiation. 15. A method of x-ray treatment of a target material comprising the steps of: placing the target material within a containment tube having a primary body and an outer surface coated with a metallic layer that is responsive to electron bombardment to emit x-ray radiation, the primary body of the containment tube being substantially transparent to x-rays, the containment tube being surrounded by an inner surface of an emitter tube, wherein the inner surface of the emitter tube comprises an electron emitter surface; extracting electrons from the emitter surface; and applying an acceleration potential between the emitter surface and the metallic layer of the containment tube, whereby the extracted electrons accelerate toward and strike the metallic layer, stimulating the release of x-ray radiation there from, at least a portion of which x-ray radiation penetrates the body of the containment tube and impinges upon the target material placed therein. 16. The method of x-ray treatment according to claim 15, wherein the target material is a liquid material. 17. The method of x-ray treatment according to claim 15, wherein the target material is a gaseous or plasma material. 18. The method of x-ray treatment according to claim 15, wherein the target material is a solid or slurry material. 19. The method of x-ray treatment according to claim 15, further comprising evacuating a space between the containment tube and the emitter tube to reduce the pressure in the space below ambient pressure. 20. The method of x-ray treatment according to claim 19, further comprising evacuating the space between the containment tube and the emitter tube to less than 10−5 torr. 21. The method of x-ray treatment according to claim 15, wherein the containment tube comprises an inlet and an outlet and wherein the step of placing the target material within the containment tube comprises introducing the material at the inlet, moving the material through the tube, and removing the material at the outlet. 22. A method of x-ray treatment of a target material comprising the steps of placing the target material within a containment tube having an outer surface having thereon an electron emitter element, the containment tube being substantially transparent to x-rays, the containment tube being surrounded by an inner surface of an x-ray tube, wherein the inner surface of the x-ray tube comprises a target layer that is responsive to electron bombardment to emit x-ray radiation; extracting electrons from the electron emitter element; and accelerating the extracted electrons toward the target layer, whereby the accelerated electrons strike the target layer stimulating the release of x-ray radiation there from, at least a portion of which x-ray radiation penetrates the containment tube and impinges upon the target material placed therein. 23. The method of x-ray treatment according to claim 22, further comprising evacuating a space between the containment tube and the x-ray emitter tube to reduce the pressure in the space below ambient pressure. 24. The method of x-ray treatment according to claim 23, further comprising evacuating the space between the containment tube and the x-ray emitter tube to less than 10−5 torr. 25. The method of x-ray treatment according to claim 22, wherein the containment tube comprises an inlet and an outlet and wherein the step of placing the target material within the containment tube comprises introducing the material at the inlet, moving the material through the tube, and removing the material at the outlet.
	summary
	summary
	claims	1. A method of ion implantation comprising:generating an ion beam having a long dimension;adjusting placement of a plurality of blockers based on beam current across said ion beam;blocking a portion of said ion beam with said blockers at a plurality of locations across said long dimension, wherein said blocking is individually controlled at said plurality of locations; andsimultaneously implanting said ion beam across a dimension of a workpiece at a first dose and a second dose after said blocking, wherein said first dose corresponds to said plurality of locations and said second dose is higher than said first dose and wherein said first dose and said second dose are both greater than zero. 2. The method of claim 1, wherein said ion beam has a non-uniform beam current, said adjusting is based on said non-uniform beam current, and said blocking is configured to implant said first dose and said second dose uniformly across said workpiece. 3. The method of claim 1, further comprising scanning said workpiece with respect to said ion beam. 4. The method of claim 1, wherein said blocking is configured to compensate for expansion of said ion beam. 5. The method of claim 1, further comprising applying conductive contacts to a plurality of regions implanted with said second dose. 6. The method of claim 2, further comprising scanning said workpiece with respect to said ion beam. 7. The method of claim 2, wherein said blocking is configured to compensate for expansion of said ion beam. 8. The method of claim 2, further comprising applying conductive contacts to said second plurality of regions. 9. A method of ion implantation comprising:generating an ion beam having a long dimension, wherein said ion beam has a non-uniform beam current;blocking a portion of said ion beam at a plurality of locations across said long dimension, wherein an amount of said blocking is individually controlled for said plurality of locations and is configured to correct for said non-uniform beam current and simultaneously implant a first dose and a second dose uniformly across a dimension of a workpiece;scanning said workpiece with respect to said ion beam; andperforming a patterned implant of said workpiece, wherein said first dose is implanted at a plurality of regions corresponding to said plurality of locations of said blocking and said second dose higher than said first dose is implanted into a remainder of said workpiece, and wherein said first dose and said second dose are both greater than zero. 10. The method of claim 9, wherein said blocking is configured to compensate for expansion of said ion beam. 11. The method of claim 9, further comprising applying conductive contacts to a plurality of regions having said second dose. 12. A method of ion implantation comprising:generating an ion beam having a long dimension;blocking a portion of said ion beam at a plurality of locations across said long dimension using a plurality of blockers configured to be independently translated in a direction perpendicular to said long dimension to form a patterned ion beam having first current regions and second current regions across said long dimension, said first current regions having a lower current than said second current regions and corresponding to said plurality of locations, wherein both said first current regions and said second current regions have a current greater than zero, and wherein said portion that is blocked is unequal at two of said plurality of locations;scanning a workpiece with respect to said patterned ion beam; andimplanting said workpiece with said patterned ion beam such that said workpiece is simultaneously implanted with said first current regions and said second current regions across a dimension of said workpiece. 13. The method of claim 1, further comprising forming a first plurality of regions having said first dose and a second plurality of regions having said second dose that is greater than said first dose, said first plurality of regions corresponding to said plurality of said locations of said blocking. 14. The method of claim 1, wherein said dimension is a width of said workpiece and further comprising scanning said workpiece in a perpendicular direction with respect to said width. 15. The method of claim 9, wherein said dimension is a width of said workpiece and wherein said scanning is in a direction perpendicular to said dimension. 16. The method of claim 12, wherein said dimension is a width of said workpiece and wherein said scanning is in a direction perpendicular to said dimension. 17. The method of claim 1, wherein said adjusting further comprises translating one of said plurality of blockers with respect to another of said plurality of blockers.
	description	In accordance with the present invention, a process is provided for the treatment of mercury containing waste in a single reaction vessel. More specifically, the mercury containing waste is treated by stabilization and encapsulation of the mercury containing waste through the use of sulfur polymer cement. The process of the invention is a two step process. The first step (step (a)) is the chemical stabilization of the mercury containing waste by combining the waste with sulfur polymer cement (SPC) under an inert atmosphere to form a resulting mixture. The second step (step (b)) is an encapsulation step in which the resulting chemically stabilized mixture from the first step is heated to form a molten product, which molten product is then cast as a monolithic final waste form. The resulting final waste form complies with EPA leaching standards. The mercury containing waste treated by the process of the invention can be any waste that is contaminated with mercury. This includes waste that is essentially mercury, that is elemental mercury or other mercury compounds; mercury contaminated bulk materials, such as sand or soil; or mercury contaminated debris, that is, material that is not particulate or is larger than particles of sand or soil (e.g. glass, stones, gravel, etc.). When processing using a screw or blade-type mixer, items of debris should be removed before the waste is processed. Debris can be removed from the rest of the waste using a sieve with a screen. A screen size up to xe2x85x9c inch is preferred for this method. The larger debris which has been removed from the initial batch of waste can be processed in the same manner as mercury contaminated bulk materials, as described below. While mercury containing waste which is essentially elemental mercury or mercury contaminated bulk materials can be mixed using an automated mixer, larger debris should be mixed by other means. For example, the SPC and mercury contaminated debris can be mixed manually or by agitation, such as with a paint shaker. The mercury containing waste can also include what is known in the art as mercury mixed waste, or waste that contains low level radioactive material as defined by Nuclear Regulatory Commission Regulations set forth in 10 C.F.R 61. Low level radioactive wastes do not include spent nuclear fuel, transuranic waste, or byproduct materials which are defined as high-level radioactive wastes in xc2xa711e(2) of the Atomic Energy Act of 1954 at 43 U.S.C. 2014(e). Environmental Protection Agency (EPA) regulations, i.e. 40 CFR 268.40, stipulate that elemental mercury be xe2x80x9camalgamatedxe2x80x9d before disposal. As defined, this xe2x80x9camalgamationxe2x80x9d requires that the mercury be combined with reagents such as copper, gold, or sulfur that result in a solid, non-volatile product. It should be noted that, according to EPA regulation 40 CFR 268.40, all processes where mercury is mixed with metals and sulfur are called amalgamation. However, combining mercury with sulfur results in mercuric sulfide (HgS), which is a new compound, not an amalgam or alloy. Mercuric sulfide is the most stable compound formed between mercury and sulfur. It exists in two stable forms. One is the black cubic tetrahedral form, which is most commonly obtained when soluble mercuric salts and sulfides are mixed. The other stable form is the red hexagonal form found in nature as cinnabar. Both forms of mercuric sulfide are insoluble in water (Ksp. red=3.0xc3x9710xe2x88x9253 M2 and Ksp. black=1.9xc3x9710xe2x88x9215 M2) and in acidic solutions. The process of the invention is designed to treat mercury containing waste by stabilizing the mercury and encapsulating the stabilized mixture. Stabilizing means reacting the mercury within the mercury containing waste with sulfur polymer cement to form mercuric sulfide. In this way, the mercury containing waste is stabilized to form an insoluble, inert, material. In the second step, the resulting stabilized mixture is encapsulated, meaning the stabilized waste is embedded within the sulfur polymer cement, thereby improving the characteristics of the final waste form. When the mercury containing waste is essentially mercury or mercury contaminated bulk materials, such as sand or soil, the stabilized particles of mercury or bulk material is encapsulated. This can be referred to as microencapsulation. If the waste contains mercury contaminated debris, the stabilized waste is macroencapsulated, meaning the larger item of debris is embedded within the sulfur polymer cement. Casting refers to forming the molten homogenous mixture of the present invention into a desired waste form for disposal, and then cooling the molten product into a final waste form. Casting is part of the encapsulation process. Casting may or may not involve the use of a collection container separate from the reaction vessel. Preferably, the cooling is performed in a vessel suitable for disposal by permitting the temperature to be reduced to below its melting point in a manner which prevents cracking or shrinking. The amount of leachable mercury is determined by EPA Toxicity Characteristic Leaching Procedure (TCLP) as set forth in Federal Register, Vol. 51, No. 114, Part 261.24, p.21685 (Jun. 13, 1986). For disposal in a landfill, a waste form currently must reach less than 0.2 mg/l of soluble mercury when subjected to a TCLP assay. EPA is phasing in more stringent requirements known as Universal Treatment Standards (UTS) in which the maximum TCLP concentration is 0.025 mg/l. The process of the invention produces a waste form with such leachability characteristics. Both steps of the invention can be conducted in a single vessel. This is particularly beneficial when handling radioactive mercury containing waste so as to minimize exposure. Also, the single vessel helps to avoid exposure to the reagents and any intermediates formed therefrom. The vessel may be any conventional container suitable to withstand the reaction temperatures, (e.g. a paint can, steel drum, etc.) fitted with appropriate known mechanisms for heating and mixing, or a known system for mixing at elevated temperatures (e.g. cone mixer, planetary mixer, porcupine mixer, pug mill, etc.). Because the process of the invention can produce mercury or sulfur vapors, it is preferred that the reaction be performed with an off-gas collection system. Any known system, such as a conventional negative pressure system, can be used. Sulfur polymer cement (SPC), also known as modified sulfur cement, is usually formed by reacting sulfur as is known with about 5-10% by weight of a hydrocarbon, such as dicyclopentadiene, to form a sulfur reaction product which is more amorphous in nature as opposed to being crystalline. The method of making such modified sulfur reaction products is known and shown for example in U.S. Pat. No. 4,290,816 and the reissue thereof, U.S. Pat. No. RE 31,575. The SPC utilized in the process of the invention is manufactured by Martin Resources, Inc., Odessa, Tex. and is marketed under the tradename CHEMENT 2000. Martin Resources uses a formulation of elemental sulfur mixed with 5 wt % of a modifier consisting of unsaturated hydrocarbon dicyclopentadiene and the monomeric form, cyclopentadiene, in a ratio of 1.0. SPC usually comes in flat, plate-like chips that are approximately 2 in. by 2 in. by xc2xc in. These chips need to be physically reduced to a particulate or powder form before being added to the mercury containing waste in the chemical stabilization step. It is preferred that the SPC be reduced to a particle size of less than 3000 microns, preferably between 10 and 250 microns. The lower particle size allows the stabilizing reaction in the first step of the process to proceed to completion more quickly. However, an SPC particle size of less than 10 microns can become difficult to physically work with and increases the flammability potential. The reduction in particle size can be performed by any known methods. For example, a ball mill containing quartz cobbles can be used for smaller samples. For large scale use, a commercial grinder can be used, e.g. Buffalo Steel Mill Company (Buffalo, N.Y.). Prior to mixing the SPC and mercury containing waste, the reaction vessel is placed under an inert atmosphere such as argon or nitrogen. This inert atmosphere serves two purposes. First, it reduces potential flammability, thus making the process safer. Second, the inert atmosphere prevents the mercury containing waste from reacting with oxygen in the air to form mercuric oxide. Mercuric oxide is a water soluble and highly leachable compound. In the first step of the process of the invention, mercury containing waste and SPC are mixed in the reaction vessel. In general, a sufficient amount of SPC is added to the mercury containing waste to create a sufficient molar excess of sulfur to elemental mercury to drive the stabilization reaction in the first step of the process to completion, i.e. for the mercury within the waste to react with the sulfur to form the insoluble mercuric sulfide. The preferred weight ratio of SPC to mercury containing waste is typically between about 0.2 to about 3.0. If the mercury containing waste is essentially mercury, approximate equal amounts by weight of mercury containing waste and SPC are preferred. This approximate 1:1 weight ratio of SPC to mercury assures a nearly six-fold molar excess of sulfur to mercury. This remains true if the waste contains radionuclides. This molar excess facilitates a faster reaction of the mercury metal with sulfur. Although the 1:1 ratio works well, other ratios are contemplated in order to optimize reaction times, material costs, and the performance of the final waste form. If the mercury containing waste is essentially mercury contaminated bulk materials or debris, it is still a requirement that enough SPC be added to the waste in step (a) so that the mercury within the waste completely reacts with the sulfur in the SPC, thereby converting the mercury to its insoluble form, mercuric sulfide. Soils and debris that contain extremely high concentrations of mercury will still contain far less concentrations than the elemental mercury waste processed by the invention. Thus, in such cases, physical processing parameters, e.g. the viscosity of the mix, will determine the amount of SPC to be added to the mercury containing waste, rather than the amount of SPC required to completely react the mercury in the waste with the sulfur in the SPC. Those skilled in the art can, therefore, determine the amount of SPC required to process mercury containing waste containing such bulk materials or debris. For example, applicants processed radioactive mercury containing waste composed mainly of sand and silt with a small percentage of gravel and approximately 5% debris, e.g. glass, metal and plastic. The waste contained significant mercury concentrations, e.g. 18,000 mg/kg. The larger debris was removed and the waste was sieved using a xe2x85x9c inch screen to remove stones and gravel. Using such waste, applicants processed mixtures up to 70 wt % soil. However, when discharging the waste material, a layer of material tended to stick to the wall of the vessel and required manual scraping. When the waste loading was reduced to 60 wt % soil, the viscosity of the mixture was lower, and most of the mixture flowed easily out of the reaction vessel and into the collection container. While the mercury containing waste is being mixed in the reaction vessel under an inert atmosphere, the mercury in the waste reacts with the sulfur in the SPC to form the insoluble compound mercuric sulfide. Hg+Sxe2x86x92HgSxe2x80x83xe2x80x83(1) Because the process includes this chemical stabilization of the mercury to an insoluble form, it meets EPA requirement for amalgamation. The mixing of the SPC and mercury containing waste can be performed manually or by any known commercial mixers. For example, the mixer can be an agitator, such as a paint shaker, or a system for mixing at elevated temperatures, such as a cone mixer, planetary mixer, porcupine mixer, pug mill, etc. This reaction in the first step in the process can occur at room temperature. To accelerate the mercuric sulfide formation in the first step of the reaction, it is preferred that the reaction vessel be heated to between about 20xc2x0 C. to about 80xc2x0 C., preferably between about 35xc2x0 C. to about 50xc2x0 C. with agitation for approximately 4-8 hours, depending on the concentration of mercury being treated. Any known method of heating the reaction vessel may be used, such as heating tape, hot oil or steam bath, etc. The reaction temperature can also be determined by any known method, such as placing a thermocouple directly into the reaction vessel. If the waste contains mainly bulk materials or debris with a relatively small concentration of mercury, less time will be required to stabilize the mercury within the waste. Those skilled in the art will be able to determine the time necessary to complete the reaction. Mercury oxides or other soluble mercury salts can exist in the metallic mercury or can be formed while processing the mercury containing waste. These soluble compounds compromise the TCLP performance of the waste forms. In such cases, a stabilizing additive can be added as a reagent to reduce the leaching of mercury salts from the resultant waste form. The stabilizing additives can be sodium sulfide (Na2Sxe2x80x949H2O), triisobutyl phosphine sulfide, also known as Cyanex 471x, calcium hydroxide, sodium hydroxide, calcium oxide, and magnesium oxide, or a combination thereof. Sodium sulfide or triisobutyl phosphine sulfide or a combination thereof are preferred. Sodium sulfide is most preferred. The amount of stabilizing additive added to the mixture, i.e. mercury containing waste and SPC, will usually be between 0.5 and 20 wt % of the final waste form, preferably between 1-12 wt %, and most preferably 2-5 wt % of the final waste form. It has been found that sodium sulfide works exceptionally well as a stabilizing additive when added in an amount approximately 2-3 wt % of the final waste form. To improve the reaction between the stabilizing additive and the other reagents, it is preferred that the stabilizing additive also be of a particle size less than about 3000 microns, preferably between about 10 to 250 microns. A mild exotherm is observed when a mixture of SPC powder, mercury waste and a stabilizing additive is heated. For example, when SPC, mercury containing waste, and sodium sulfide or triisobutyl phosphine sulfide were mixed and warmed to approximately 35xc2x0 C., the temperature of the reaction mixture rises to approximately 70xc2x0 C. for several hours, after which the reaction is complete. This makes it possible to process an aliquot of mercury containing waste by the process of the invention in two to eight hours compared with the sixteen hour cycle required without the use of additives or elevated temperature. Thus, the addition of the stabilizing additive not only improves the leachability characteristics of the resulting waste form, but also significantly cuts down on the reaction time required for the process. In the second step of the process (step (b)), the chemically stabilized mixture from step (a) is encapsulated by increasing the temperature of the stabilized mixture to form a molten product, and casting the molten product as a monolithic final waste form. If necessary, additional SPC can be added during the encapsulation step so that the viscosity of the molten mixture may be suitable for homogenous mixing. If additional SPC is added, it is preferred, although not necessary, that the additional SPC also be of a particle size of less than 3000 microns. As with the chemical stabilization step, less additional SPC will be required in the encapsulation step if the mercury containing waste to be treated contains a relatively low concentration of mercury. If additional SPC is added, the additional SPC is added to the resulting mixture of step (a) so as to form a waste loading of usually about 5 wt % to about 90 wt % in the final waste form. If the mercury containing waste is essentially mercury contaminated bulk materials or debris and additional SPC is added, the additional SPC is usually added in an amount to form a waste loading of about 25 wt % to about 80 wt % in the final waste form, preferably about 50 wt % to about 70 wt %. If the mercury containing waste is essentially mercury and additional SPC is added, the additional SPC is usually added in an amount to form a waste loading of about 10 wt % to about 50 wt % in the final waste form, preferably about 30 wt % to about 35 wt %. The increase in temperature during the encapsulation step must be above the melting point of the SPC and sufficient to convert the stabilized mixture in step (a) to a molten product. The temperature required is usually between about 120-150xc2x0 C., preferably about 130-140xc2x0 C. The molten product is then cast as a monolithic final waste form. The waste form can be cast in any conventional container, preferably a container suitable for disposal, e.g., steel canister. The following examples are provided to assist in a further understanding of the invention. The particular materials and conditions employed are intended to be further illustrative of the invention and are not limiting upon the reasonable scope thereof. Five (5) kilograms of elemental mercury waste and 5 kilograms of SPC were added to a single reaction vessel, thereby forming a 1:1 ratio by weight. SPC was provided by Martin Resources (Odessa, Tex.) and contained 95% elemental sulfur. The Buffalo Steel Company (Buffalo, N.Y.) was contracted to grind the SPC into a powder of a particle size less than 250 microns. The reaction vessel was a 5-gallon heavy-gauge steel drum attached to a paint shaker (5033 Series Red Devil, Minneapolis, Minn.). Quartz stones were added to enhance mixing. Heating tape attached and surrounded the steel drum in order to heat the reaction mixtures. To monitor and control the temperature, a thermocouple was inserted into the vessel and connected to a digital PID controller. The reaction vessel was equipped with openings that allow venting gases from the heating of the sulfur polymer cement. The reaction vessel and paint shaker were located inside a walk-in fume hood, to allow any mercury or sulfur vapors to be safely dispersed. After the materials were loaded, argon gas was used to purge any air from the reaction vessel. The reaction mixture was then heated to approximately 40xc2x0 C., while mixing, for about four (4) to eight (8) hours to allow the mercury and the sulfur within the SPC to react to form mercury sulfide (HgS). To test the progress of the stabilization reaction, an aliquot (approximately 10 grams) of the crude reaction mixture was placed in a centrifuge tube and spun between 7,500 and 10,000 rpm for one hour. Centrifugation was performed using a Sorval RC-5 centrifuge. When unreacted elemental mercury remained in the mixture, a visible layer of mercury formed on the surface of the tube. In one sample, where the amount of unreacted mercury was significant, it was separated and weighed. The isolated mercury was 0.75 grams and the remaining sample was 9.83 grams. Therefore, approximately 15% of the mercury was unreacted and isolated, i.e., the reaction was 85% completed. This simple method can be used to determine when the reaction is 99% complete. In general, as indicated above, it will take 4-8 hours for the sulfur to completely react with the mercury in the waste. Less time is required if a stabilizing additive is used. When the reaction was complete, 5 kg of additional SPC was added to the resulting mixture from the first step, forming a waste loading of about 33 wt % in the final waste form. After the additional SPC was mixed for about four (4) hours, the temperature was raised to approximately 135xc2x0 C., until the mixture melted. The resulting homogenous molten product was then cast by pouring it into paint cans and allowing it to cool to form a monolithic waste form. In a separate example, a stabilizing additive was added to 5 kg of mercury mixed waste and 5 kg of SPC. In one sample, sodium sulfide nonahydrate (Na2Sxe2x80x949H2O) obtained from the Cooper Chemical Company (Long Valley, N.J.) was added in an amount of 3% by weight of the waste form. In another sample, triisobutyl phosphine sulfide (Cyanex 471x) obtained from Cytec Corporation (Niagra Falls, ON) was added in an amount of 3% by weight of the waste form. In a third sample, a combination of Na2S9H2O and Cyanex 471x were added each in an amount of 1.5% by weight of the waste form. After the reagents were added, they were mixed and warmed to a temperature of approximately 35xc2x0 C. Due to the exotherm of the reaction, the temperature would rise to approximately 70xc2x0 C. for several hours, after which the first step of the process was complete. Five (5) kg of additional SPC was then added to the resulting mixture to again form a waste loading of approximately 33 wt % in the final waste form. After the additional SPC was mixed for about four (4) hours, the temperature was raised to approximately 135xc2x0 C., until the mixture melted. The resulting homogenous molten product was then cast by pouring it into paint cans and allowing it to cool to form a monolithic final waste form. TCLP assays were then obtained on the samples to test the leachability of the resulting monolithic waste form. A TCLP assay was also obtained on unprocessed mercury as a baseline. The TCLP assay was obtained for the unprocessed mercury using a Liberty 100 Inductively Coupled Plasma (ICP) Spectrometer. The method of using this equipment is well known in the art. However, its sensitivity is somewhat limited to approximately 100 ppb. Therefore, the TCLP assays were obtained on the remaining samples using cold vapor analyses (EPA method 7470) which is also well known in the art. The cold vapor analyses were performed using a Perkin Elmer Model 4000 Atomic Absorption Spectrometer with a Perkin Elmer Model MHS-10 Mercury/Hydride system. TCLP specimens were fabricated as pellets in Teflon(copyright) molds, capable of passing through a 9.5 mm sieve. The results of the TCLP assays are shown in Table 1. The results demonstrate that the samples with sodium sulfide as an additive consistently result in acceptable levels of mercury in TCLP leachates. Assay IV containing sodium sulfide as the sole additive and Assay V containing equal parts of sodium sulfide and Cyanex 471x as additives, yielded very favorable TCLP results of 0.02 and 0.026 mg/l, respectively. Assay II demonstrates the process as being effective without any stabilizing additive with a TCLP result of 0.02 mg/l. In the cases where the samples did not meet TCLP leaching requirements, the reaction to HgS was not complete, most likely due to inadequate processing time. Long term leachability was evaluated for Assay IV according to the Accelerated Leach Test. See, ASTM, xe2x80x9cAccelerated Leach Test for Diffusive Releases from Solidified Waste and a Computer Program to Model Diffusive, Fractional Leaching from Cylindrical Waste Forms,xe2x80x9d ASTM C-1308-95, American Society of Testing Materials, West Conshocken, Pa., 1995. This method is a dynamic test in which the distilled water leachant is replaced on a periodic basis. Data is evaluated using a related computer program that calculates incremental and cumulative contaminant fractions released, identifies predominant leaching mechanisms and effective diffusion coefficient, and enables prediction of long-term releases if diffusion is the controlling mechanism. Leach results closely match those predicted by the diffusion model, indicating that diffusion is the predominant leaching mechanism. Following eleven days of leaching, a total of only 5.8xc3x9710xe2x88x924 percent of the mercury leached from the waste form. The effective diffusion coefficient was measured to be 4.15xc3x9710xe2x88x9218. The effect of the additives was further investigated using X-ray powder diffraction. When no stabilizing additive is added to the mercury waste and the SPC., or when Cyanex 471x is used as the stabilizing additive, the resulting waste form is lustrous black. When sodium sulfide is used as the stabilizing additive, the resulting waste form is a dull orange color. These observations correspond with the known fact that mercuric sulfide has two stable forms. One is a cubic phase that is black. The other is an orthorhombic phase that is red. X-ray powder diffraction studies were then performed to characterize the chemical species in the waste forms. A crushed sample of the black waste form from the process of the invention using only elemental mercury and SPC was analyzed. The powder diffraction pattern is shown in FIG. 1 and tabulated in Table 2. The diffraction pattern shows the black waste form to be composed of a form of mercuric. sulfide, also known as metacinnabar (See, Swanson, H. E., Fuyat, R. K., and Ugrinic, G. M., xe2x80x9cStandard X-Ray Diffraction Patterns,xe2x80x9d Circular 539, Volume 4, pp. 17-22 (1955)), and sulfur (See, Sliva, P., Peng, Y. B., Peeler, D. K. Bunnel, L. R., Turner, P. J., Martin, P. F., and Feng, X., xe2x80x9cSulfur Polymer Cement as a Low Level Waste Glass Matrix Encapsulant,xe2x80x9d PNNL-10947, Pacific Northwest National Laboratory, Richland, Wash., January 1996). The diffraction pattern study, therefore, demonstrates that the process of the invention is effective in converting mercury waste into its insoluble form, mercuric sulfide. When Cyanex 471x is added to the reaction mixture of mercury and powdered SPC., the final product is a lustrous black waste form. The powder diffraction pattern from a crushed sample of that material is shown in FIG. 2. The results from the pattern in FIG. 2 are tabulated in Table 3. As in the waste prepared with no additive, the waste material is a mixture of metacinnabar and sulfur. When sodium sulfide is added as a stabilizing additive in the reaction mixture of mercury and SPC., a reddish brown waste form is produced. The powder diffraction pattern from that material is shown in FIG. 3. The data, tabulated in Table 4, indicate the mixture to be a mixture of hexagonal mercuric sulfide, also called cinnabar (See, Swanson, et al (1955).), and orthorhombic sulfur (See Swanson, H. E., Cook, M. I., Isaacs, T., Evans, E. H., xe2x80x9cStandard X-ray Diffraction Powder Patterns,xe2x80x9d Circular 539, Vol. 9 (1960). A sample of stabilized mercuric sulfide was also examined before adding additional SPC in step (b). The diffraction pattern of a sample, taken from the reaction mixture of sodium sulfide, mercury and SPC gave a diffraction pattern that was essentially identical to that obtained from the previously examined final waste form, shown in FIG. 3. This indicates that the solidification processes do not affect the mercuric sulfide formed during the stabilization step, i.e. the first step of the process. Thus, from the X-ray diffraction data, two isomorphs of crystalline mercuric sulfide from the reaction of elemental mercury and sulfur are observed. One isomorph of mercuric sulfide, cinnabar, has a hexagonal structure and a red color. The other form, metacinnabar, is black and has a cubic structure. The waste forms consisting of cinnabar performed better in the TCLP assays. Adding sodium sulfide results in an exotherm and forces the reaction or mercury in the waste and sulfur in the SPC to cinnabar. Adding Cyanex 471x also results in an exotherm, but the final product is metacinnabar. The results suggest that the different crystal formation of the cinnabar increases its leaching performance. The volatility of the mercury containing waste was also examined during various stages of the processing. Mercury vapor is a workplace hazard with a low Threshold Limit Value (TLV) level of 0.05 mg/m3. During the first step of the process, mercury vapor was tested using a Drager tube obtained from Sargent Welch (Philadelphia, Pa.), which has a detection limit of 0.05 mg/m3. During processing, a Drager tube was placed in front of the ventilating port for the reaction vessel. During the first step of the reaction, when the elemental mercury was warmed to approximately 40xc2x0 C. for about four (4) hours, a Drager test tube showed 2 mg/m3 mercury vapors in the atmosphere. The reaction vessel was then placed in a hood, and the entrance and venting ports were covered with glass wool to reduce the escape of mercury vapor. After the mercuric sulfide was formed, no mercury vapor was detected in the reaction vessel. During the second step of the reaction, when additional SPC was added and the reaction vessel heated to approximately 135xc2x0 C. until the mixture melted, no mercury vapor was detected, i.e. less than 0.05 mg/m3. The amount of mercury vapor generated from the final waste forms was also measured quantitatively using the following method. Small samples (approximately seven (7) grams) of the waste form were placed in 250 ml plastic bottles. The mercury vapors were permitted to come to equilibrium at room temperature, for about eighteen (18) hours. A 5 ml sample of air from the headspace of the bottle was then taken. The headspace sample was injected into a glass bottle and sealed with a septum. An argon stream carried any mercury vapor to the absorption cell of a Perkin Elmer Model MHS-10 Mercury/Hydride system, where the vapor concentration was measured using the cold vapor apparatus of the Perkin Elmer Model 400 Atomic Absorption Spectrometer. This method was calibrated using known quantities of a mercury standard using techniques identical to the mercury cold vapor method (EPA method 7470). Measured quantities of 100 ppb mercury standard solution and stannous chloride were injected into 260 cc septum topped bottles. The reaction between the two reagents quantitatively generated Hg vapor. Five ml of this vapor were withdrawn by syringe and injected into the gas mixing chamber on the cold vapor apparatus on the Atomic Absorption Spectrometer. The calibration figures produce a linear plot, shown in FIG. 4. Equilibrium mercury vapor concentrations were characteristic of the different materials analyzed and are shown in Table 5. As shown in Table 5, the Hg vapor concentration over the elemental mercury was about 100 ug/L. The vapor concentration over the elemental mercury was measured periodically over several weeks and was reproducible. The results demonstrate that mercury waste treated by the process of the invention had much lower Hg vapor concentrations, typically at least an order of magnitude lower than elemental mercury. Waste forms produced with sodium sulfide as a stabilizing additive on average had lower vapor concentrations than the other treated wastes. However, applicants believe that this was a function of the age of the waste material. Table 5 shows that the new waste sample from Hg, SPC, and sodium sulfide had a vapor concentration approximately 3xc2xd times that of the sample formed one week earlier by the same reagents. The effect of how vapor concentration changes over time is demonstrated in FIG. 5. The concentration of Hg vapor was measured by the cold vapor method using the Atomic Absorption Spectrometer as described above. The concentration of Hg vapor sharply decreases over the span of one week from approximately 37 ug/L to approximately 3 ug/L. The decrease in Hg vapor is because of the continued reaction between the sulfide and the mercury to form HgS, with its lower vapor concentrations. Mixed mercury waste containing various radionuclides, shown in Table 6 was treated by the process of the invention. This mercury mixed waste was treated identically to that of the uncontaminated mercury waste in Example 2, using sodium sulfide nonahydrate additive. After processing, the molten mixtures were poured into one gallon paint cans and cooled. A total of five batches of waste forms, each consisting of three paint cans, were produced for disposal. A 10 g sample was taken from each of the five batches to form a single 50 g sample. A TCLP test was then conducted on the 50 g sample. This resulted in a TCLP concentration of 50 ppb, well below the EPA limit of 200 ppb. This example demonstrates the process of the invention in treating mercury contaminated sand or soil. The waste was treated using the process as set forth in Example 2, using sodium sulfide as a stabilizing agent in an amount of approximately 2 wt % of the resulting waste form. The subject waste was obtained from a remedial excavation of the Animal/Chemical Pits And Glass Holes conducted at Brookhaven National Laboratory in the Summer of 1997 in compliance with CERCLA and the New York State Regulations. Approximately 100 ft3 containing greater than 260 ppm were segregated into two partially filled B-25 boxes. The physical composition of the soil was mostly sand and silt. The soil also contained a small percentage of gravel and approximately 5% debris (glass, metal and plastic), most of which was removed during subsequent repackaging operations. During excavation, the soil was screened to less than 1 inch. Significant homogenization of the soil and the B-25 boxes occurred during this segregation/screening process. Composite characterization data, summarized in Table 7, indicate average total mercury concentrations of 6,750 mg/kg and 18,000 mg/kg. Representative samples of each waste bin were TCLP tested yielding mercury concentrations of 3.56 mg/l and 0.26 mg/l, respectively, above current 0.2 mg/l limit, making them subject to EPA Land Disposable Restriction treatment standards. In addition to the varying levels of mercury, the two drums differed in isotopic mixture and concentrations. One contained relatively high concentrations of Am-241 and the other primarily Eu-152 and Ra-226. Each B-25 box of soil was subdivided into seven 55-gallon drums. To ensure testing of comparable wastes, the soil was evenly divided when repackaged by manually shoveling small scoops into each drum in turn. The drums were assigned a unique identification number (A1-A7 for drums from Box 1 which contains Am and E1-E7 for drums from Box 2 which contains Eu). Large pieces of debris were manually removed while repackaging. Prior to processing, the soil was re-sieved using a xe2x85x9c inch screen, and a small quantity of stones were removed. Although the soils tested in this Example contained relatively high concentrations of mercury (up to 5570 mg/kg), they contained far less mercury on a mass basis than the elemental mercury waste processed in Example 1. Thus, physical processing parameters, e.g., viscosity of the mix, rather than mercury leachability, represent the limited constraint on maximum waste loading. Using a commercial vertical cone blender, mixtures containing up to 70 wt % soil processed. However, when discharging the mixture at this waste loading, a layer of material tended to stick to the walls vessel and require manual scraping. When the waste loading was reduced to 60 wt % soil, the viscosity of the mixture was lower, and most of the mixture flowed easily out of the reaction vessel into the collection container. At this waste loading, the volume of treated waste was virtually the same as the untreated waste, i.e., no increase in volume resulted. This is due to the filling of void spaces in the soil by molten SPC. Processing was accomplished using a pilot-scale vertical cone blender/dryer (Ross Mixers, Hauppauge, N.Y.) with a capacity of 1 ft3. A total of 12 batches of soil were processed to complete the pilot scale treatment of two 55-gallon drums of waste. Six batches were taken from drum A4 and six batches from E1. Approximately 20 g of treated material from each batch was prepared for composite TCLP analyses. The treatment for samples from drum A4 included the addition of sodium sulfide in an amount of 2 wt % of the final waste form. The treatment for samples from drum E1 did not include the addition of a stabilizing additive. Composite data from the six batches from drum A4 and six batches from drum E1, are summarized in Table 8. The composite data for A4 indicate extremely low leachability for mercury, 0.005 mg/l. The composite data for E1, without the use of a stabilizing additive, resulted in a higher, but acceptable, leachability for mercury, 0.147 mg/l. This is compared with the untreated soil (0.914 mg/l), the current TCLP limit (0.2 mg/l), and the more stringent Universal Treatment Standard (UTS) (0.025 mg/l). The examples and description above demonstrate that the process of the invention is effective in stabilizing and solidifying mercury containing waste and mixed waste. The process reduces mercury solubility to enable compliance with EPA TCLP criteria, lowers mercury vapor pressure during processing and in the final product, eliminates dispersibility of the stabilized product, and reduces leachability of radioactive constituents. The process, therefore, provides a cost-effective solution for the treatment of mercury containing waste stored in such areas as the Department of Energy Complex, and elsewhere. Thus, while there have been described what are presently believed to be the preferred embodiments of the invention, those skilled in the art will realize that changes and modifications may be made thereto without departing from the spirit of the invention, and it is intended to claim all such changes and modifications as fall within the scope of the invention.
	claims	1. A method for totally or partially separating uranium(VI) from plutonium(IV), without reducing plutonium(IV) to plutonium(III), from an aqueous solution A1 issued from the dissolution of a spent nuclear fuel in nitric acid, comprising:a) a co-extraction of uranium(VI) and plutonium(IV) from the aqueous solution A1, the co-extraction comprising at least one contacting, in an extractor, of the aqueous solution with an organic solution S1 comprising a carbamide as an extractant in an organic diluent, followed by separating the aqueous solution from the organic solution, the carbamide being of formula(I):wherein:R1, R2 and R3, identical or different, represent a linear or branched alkyl group, comprising from 1 to 12 carbon atoms, a cycloalkyl group comprising from 3 to 12 carbon atoms or a cycloalkylalkyl group comprising from 4 to 13 carbon atoms;R4 represents a hydrogen atom, a linear or branched alkyl group, comprising from 1 to 12 carbon atoms, a cycloalkyl group comprising from 3 to 12 carbon atoms or a cycloalkylalkyl group comprising from 4 to 13 carbon atoms;b) a stripping of plutonium(IV) and a fraction of uranium(VI) from the organic solution issued from a), the stripping comprising at least one contacting, in an extractor, of the organic solution with an aqueous solution A2 comprising from 0.1 mol/L to 0.5 mol/L of nitric acid, followed by separating the organic solution from the aqueous solution; andc) an extraction of all or part of the uranium(VI) fraction present in the aqueous solution issued from b), the extraction comprising at least one contacting, in an extractor, of the aqueous solution with an organic solution S2 comprising the carbamide in an organic diluent, followed by separating the aqueous solution from the organic solution;whereby an aqueous solution comprising plutonium(IV) without uranium(VI) or a mixture of plutonium(IV) and uranium(VI), and an organic solution comprising uranium(VI) without plutonium(IV) are obtained. 2. The method of claim 1, in which the carbamide comprises a total number of carbon atoms between 17 and 25. 3. The method of claim 1, in which R1, R2, R3 and R4 represent a linear or branched alkyl group, comprising from 1 to 12 carbon atoms. 4. The method of claim 1, in which R1 and R2 are identical and represent a linear or branched alkyl group, comprising from 1 to 5 carbon atoms, R3 and R4 are identical and represent a linear or branched alkyl group, comprising from 6 to 10 carbon atoms, and the carbamide comprises a total number of carbon atoms equal to 19, 21 or 23. 5. The method of claim 1, in which R1 and R4 are identical and represent a linear or branched alkyl group, comprising from 1 to 5 carbon atoms, R2 and R3 are identical et represent a linear or branched alkyl group, comprising from 6 to 10 carbon atoms, and the carbamide comprises a total number of carbon atoms equal to 19, 21 or 23. 6. The method of claim 1, in which R1, R2, R3 and R4 are identical and represent a linear or branched alkyl group comprising from 4 to 8 carbon atoms. 7. The method of claim 1, in which R1, R2 and R3 represent a linear or branched alkyl group, comprising from 1 to 12 carbon atoms and R4 represents a hydrogen atom. 8. The method of claim 1, in which R1, R2 and R3 are identical and represent a linear or branched alkyl group, comprising from 6 to 8 carbon atoms. 9. The method of claim 1, in which the carbamide is N,N,N′-tri-n-octylurea, N,N,N′-tri(2-ethylhexyl)urea, N,N-di(2-ethylhexyl)-N′-n-octylurea, N,N,N′,N′-tetra-n-butylurea, N,N,N′,N′-tetra-n-pentylurea, N,N,N′,N′-tetra-n-hexylurea, N,N,N′,N′-tetra-n-octylurea, N,N′-di-n-butyl-N,N′-di-n-hexylurea, N,N′-di-n-heptyl-N,N′-di-n-propylurea, N,N′-diethyl-N,N′-di-n-octylurea or N,N′-dimethyl-N,N′-di-n-nonylurea. 10. The method of claim 1, in which the organic solutions S1 and S2 comprise from 0.5 mol/L to 2 mol/L of the carbamide. 11. The method of claim 1, in which a) further comprises a decontamination of the organic solution issued from the co-extraction of uranium(VI) and plutonium(IV) with respect of americium, curium and fission products, the decontamination comprising at least one contacting, in an extractor, of the organic solution with an aqueous solution A3 comprising from 1 mol/L to 6 mol/L of nitric acid, followed by separating the organic solution from the aqueous solution. 12. The method of claim 1, in which the contacting, in the extractor of b), of the organic solution issued from a) with the aqueous solution A2 comprises a counterflow circulation of the organic solution and the aqueous solution A2 with a flow rate ratio O/A which is greater than 1. 13. The method of claim 1, which further comprises a stripping of uranium(VI) from the organic solution issued from c), the stripping comprising at least one contacting of the organic solution with an aqueous solution A5 comprising at most 0.05 mol/L of nitric acid, followed by separating the organic solution from the aqueous solution.
056169272	description	DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As is described above, the frame-supported pellicle of the invention comprises, as the essential elements, (a) a pellicle frame, (b) a pellicle membrane and (c) a layer of a pressure-sensitive adhesive, of which the pellicle frame and pellicle membrane are rather conventional and the most characteristic feature of the inventive pellicle consists in the use of a very specific pressure-sensitive adhesive which can be imparted with a reduced adhesive bonding strength when it is heated or irradiated with a radiation such as ultraviolet light. The reduction in the adhesive bonding strength of a pressure-sensitive adhesive can be caused by several different mechanisms including crosslink formation between polymeric molecules, degradation of the polymeric molecules and foaming within the adhesive layer. At any rate, it is essential that a decrease is caused in the stickiness of the surface of the adhesive layer when it is subjected to a heat treatment or to an irradiation treatment with a radiation such as ultraviolet light to such an extent that the adhesive layer left adherent to the photomask surface after removal of the pellicle frame therefrom can be easily removed to bring the surface of the photomask into a completely clean condition suitable for mounting of another frame-supported pellicle without using any risky or harmful means mentioned above. Various kinds of pressure-sensitive adhesives are used on conventional frame-supported pellicles including those based on a polybutene resin, polyvinyl acetate resin, acrylic resin, silicone resin and the like for the purpose of securing the flame-supported pellicle mounted on a photomask but none of these conventional pressure-sensitive adhesives exhibits a reduction in the adhesive bonding strength when subjected to a heat treatment or irradiation treatment with a radiation. It is necessary accordingly that these adhesive polymers are chemically modified so as to introduce a specific functional structure susceptible to heating or irradiation with light to cause crosslinking or decomposition resulting in reduction of the adhesive bonding strength. Alternatively, the pressure-sensitive adhesive is admixed with a blowing agent so that foaming takes place in the adhesive layer to form a foamed layer having decreased surface stickiness when the layer is heated or irradiated with light. These pressure-sensitive adhesives can be applied as such to the end surface of the pellicle frame. It is optional that a foamed sheet of a rubber such as a polyurethane rubber impregnated or coated with the pressure-sensitive adhesive is attached to the end surface of the pellicle frame. It is further optional according to need that the pressure-sensitive adhesive is admixed with a filler or a pigment. It is a desirable condition that the pressure-sensitive adhesive retains the adhesive bonding strength prolongedly with stability when the adhesive layer is at a temperature, e.g., room temperature, lower than a critical temperature or under irradiation with light of an intensity lower than a critical intensity but the adhesive bonding strength thereof is rapidly decreased when the adhesive layer is heated at a temperature higher than the critical temperature or irradiated with light of an intensity exceeding the critical intensity because otherwise the adhesive bonding strength of the adhesive layer is gradually but steadily decreased even under normal conditions eventually to cause inadvertent falling of the frame-supported pellicle from the photomask. As to the temperature of the heat treatment, the above mentioned critical temperature should be in the range from 40.degree. C. to 300.degree. C. or, preferably, from 70.degree. C. to 150.degree. C. because, when the critical temperature is too low, the decrease in the adhesive bonding strength of the adhesive layer proceeds even at room temperature while, when the critical temperature is too high, a high-temperature heat source must be brought into the clean room to uneconomically put an excessive load on the air-conditioning system of the clean room. When the adhesive layer is irradiated with light in order to be imparted with a reduced adhesive bonding strength, the wavelength of the light is not particularly limitative provided that the desired photochemical reaction can be induced thereby in the pressure-sensitive adhesive. Since the light is desirably ultraviolet in view of the high photochemical efficiency, suitable light sources include high-pressure and low-pressure mercury lamps, metal halide lamps and the like available at low costs. It is desirable to use an ultraviolet-curable pressure-sensitive adhesive of which the adhesive bonding strength can be definitely decreased by the irradiation with ultraviolet light in an irradiation dose of 500 mJ/cm.sup.2 or larger or, preferably, 200 mJ/cm.sup.2 or larger. Electron beams and X-rays are, though effective for the purpose, not preferable because they can be generated only by using very expensive and large instruments. In the following, the frame-supported pellicle of the present invention is described in more detail by way of examples. EXAMPLE 1 A membrane having a thickness of 0.815 .mu.m prepared from an amorphous fluorocarbon resin (Cytop, a product by Asahi Glass Co.) was spread over an end surface of a surface-anodized duralumin-made rectangular frame having outer side lengths of 120 mm by 98 mm, thickness of 2 mm and height of 5.8 mm and adhesively bonded thereto in a slack-free fashion by using a solution of the same fluorocarbon resin as the adhesive. A heat-curable pressure-sensitive adhesive tape (Liva-alpha No. 3195, a product by Nitto Denko Co.) was attached and bonded to the other end surface of the pellicle frame. This adhesive tape can be imparted with a decreased adhesive bonding strength when it is heated as is illustrated by the graphs shown in FIGS. 1 and 2 of the accompanying drawing showing the adhesive bonding strength in g per 20 mm width as a function of the temperature at-which the adhesive tape is contacted with a metallic surface for 1 minute (FIG. 1) and as a function of the heating time in seconds when the adhesive tape is heated at 100.degree. C.. As is understood from these graphs, the adhesive tape is stable at room temperature but rapidly loses the adhesive bonding strength when it is heated at 80.degree. C. or higher resulting in complete loss of the bonding strength by heating for i minute at 90.degree. C. or higher and only 1 second of heating is sufficient to cause complete disappearance of the adhesive bonding strength when the heating temperature is 100.degree. C. or higher. The above prepared frame-supported pellicle with the adhesive tape on one end surface of the pellicle frame was mounted on a photomask used in the patterning work for LSIs to find that reliable mounting could be obtained by virtue of the adhesive tape. The assembly of the photomask and the flame-supported pellicle mounted thereon was heated at 100.degree. C. for 3 seconds to find that the pellicle frame could be lifted from the photomask surface without any sticking resistance due to the substantially complete loss of the adhesive bonding strength on the adhesive tape. The surface of the photomask after removal of the frame-supported pellicle therefrom was so clean with no fragments of the adhesive tape left adherent thereto that the photomask was ready for mounting of another frame-supported pellicle. In contrast thereto, an attempt was made to separate the photomask and the frame-supported pellicle without undertaking the heating treatment at 100.degree. C. for 3 seconds to find that the attempt failed because the frame-supported pellicle could not be removed from the photomask without deformation of the pellicle frame. EXAMPLE 2 A frame-supported pellicle was prepared in substantially the same manner as in Example 1 excepting replacement of the heat-curable pressure-sensitive adhesive tape with an ultraviolet-curable pressure-sensitive adhesive tape (UC 1827, a product of Furukawa Denko Co.). FIG. 3 of the accompanying drawing shows that the ultraviolet-curable pressure-sensitive adhesive tape exhibited a decrease in the adhesive bonding strength given in g per 25 mm width when the tape attached to a mirror-polished surface of a semiconductor silicon wafer was irradiated with ultraviolet light from a metal halide lamp of an output of 80 watts/cm at 20.degree. C. in an atmosphere of 65% relative humidity and then peeled off the substrate surface in the direction to make an angle of 90.degree. at a pulling velocity of 50 mm/minute. The frame-supported pellicle with the pressure-sensitive adhesive tape on one end surface of the frame was mounted on a photomask for patterning of a liquid crystal display panel and the pressure-sensitive adhesive tape in the thus prepared assembly of the frame-supported pellicle and photomask was irradiated with ultraviolet light from a metal halide lamp in a dose of 500 mJ/cm.sup.2 to cause a decrease in the adhesive bonding strength between the pellicle frame and the photomask to about 1/5 of the strength before irradiation so that the flame-supported pellicle could be easily demounted from the photomask leaving absolutely no fragments of the adhesive tape remaining on the photomask. When the frame-supported pellicle was removed from the photomask without undertaking the ultraviolet irradiation, in contrast thereto, fragments of the adhesive tape were left adherent to the photomask surface which could be removed only after swelling with an organic solvent.
	abstract	A module for storing high level radioactive waste includes an outer shell, having a hermetically closed bottom end, and an inner shell forming a cavity and being positioned inside the outer shell to form a space therebetween. At least one divider extends from the top to the bottom of the inner shell to create a plurality of inlet passageways through the space, each inlet passageway connecting to a bottom portion of the cavity. A plurality of inlet ducts each connect at least one of the inlet passageways and ambient atmosphere, and each includes an inlet duct cover affixed atop a surrounding inlet wall, the inlet wall being peripherally perforated. A removable lid is positioned atop the inner shell and has at least one outlet passageway connecting the cavity and the ambient atmosphere, the lid and the top of the inner shell being configured to form a hermetic seal therebetween.
060027347	abstract	A technique for assaying samples entails irradiating a sample with a beam of gamma rays of sufficient energy to excite the nuclei of the assay elements into their isomeric states, ceasing the irradiation, detecting the gamma rays resulting from the decay of the isomeric states to the ground state, and analyzing the detected gamma rays to determine the content of assay elements in the sample. In a preferred embodiment, the apparatus is configured such that the irradiated sample is rapidly moved to a shielded environment in which the gamma rays from the isomeric transitions are detected. The system is ideally suited for analyzing large samples of ore for gold, silver, barium and other assay elements, but can be embodied to detect any assay elements susceptible to photon activation analysis in any sample geometry.
056152396	description	DETAILED DESCRIPTION OF THE DRAWINGS FIG. 1A is a side view of a reactor pressure vessel 20. The location of certain components of known differential pressure and liquid control line apparatus is indicated by line 1B--1B in FIG. 1A. Such apparatus is shown in more detail in FIG. 1B. Specifically, and referring to FIG. 1B, a pressure vessel wall 22 is shown as having a channel 24 formed therein. A nozzle 26 is formed integrally with wall 22 and extends therefrom. A core shroud 28 is supported by a shroud support cylinder 30. A shroud support plate 32 extends from and between vessel wall 22 and shroud support cylinder 30. Shroud 28 forms a partial enclosure around a core plate 34, having an opening 36 formed therein. The above described reactor vessel 20 and vessel components, such as shroud 28 and core plate 34, are substantially similar to the vessel assemblies in a number of boiling water nuclear reactors, such as the BWR 3, 4, and 5 of General Electric Company. With respect to known core differential pressure and liquid control line apparatus, various aspects of one such known apparatus is illustrated in FIGS. 1B, 1C and 1D. Specifically, such apparatus includes a tube assembly 50 which extends from opening 24 in vessel wall 22. Assembly 50 extends from opening 24 to a connector 52. Assembly 50 includes an outer, larger diameter tube 54 and an inner, smaller diameter tube. The inner, smaller diameter tube is positioned within larger diameter tube 54. A first tube 56 extends from connector 52 to an elevation location below core plate 34. A second tube 58 extends from connector 52 and to an elevation above core plate 34. First tube 56 is in flow communication with the inner, smaller diameter tube of tube assembly 50. Second tube 58 is in flow communication with the outer, larger diameter tube 54. Support brackets 60, 62 and 64 are utilized to provide support for tube assembly 50 and tubes 56 and 58. The larger diameter outer tube 54 of tube assembly 50 is welded, using a fillet weld 66, to the inner surface of vessel wall 22 at the location of opening 24. Referring to FIG. 1C, inner, smaller diameter tube 68 of assembly 50 extends through channel 24 and into tee-connector 26. The outer diameter of tube 68 is smaller than the diameter of opening 24. Also, tee-connector 26 includes a bore 38, and tube 68 has a diameter smaller than the diameter of bore 38. An end 70 of tube 68 is in flow communication with a first port 72 of tee-connector 26. An annulus 72 is formed between the outer surface of tube 68 and bore 38. Annulus 72 is in flow communication with a second port 74 of tee-connector 26. A pressure line 76 is couple to, and extends from, second port 74. FIG. 1D is a more detailed view of connector 52, illustrated in FIG. 1B. Tube assembly 50 is coupled at a first end 78 of connector 52. First tube 56, which is coupled to the inner tube (i.e., tube 68) of assembly 50, extends from a second end 80 of connector 52. Second tube 58, which is coupled to outer tube 54 of assembly 50, extends from a port 82 formed in connector 52. In operation, and to measure the core differential pressure, pressure meters may be coupled to first and second ports 70 and 74 of tee-connector 26. The pressure meter coupled to first port 70 provides a measurement of the core pressure at the elevation of the open end of first tube 56. The pressure meter coupled to second port 74 provides a measurement of the core pressure at the elevation of open end of second tube 58. By comparing such measurements, the core differential pressure can be determined. With respect to the injection of a liquid neutron absorbent, such liquid may be injected into tube 68 at first port 70 of tee-connector 26. The absorbent will flow through tube 68, connector 52 and first tube 56 to the open end thereof. As a result, such absorbent will be injected into the core of an elevation below core plate 34. FIGS. 2A and 2B are side and top plan views, respectively, of another known core differential pressure and neutron absorbent injection apparatus. Reactor components shown in FIGS. 2A and 2B which are the same as the reactor components shown in FIG. 1B are labelled using the same reference numerals in FIGS. 2A and 2B as are used in FIG. 1B. Referring to FIGS. 2A and 2B, a tube assembly 100 extends from weld 66 to a first connector 102. Tube assembly 100 includes an outer, larger diameter tube having an inner, smaller diameter tube positioned therein. A first tube 104 extends from first connector 102 to an elbow connector 106. First tube 104 is in flow communication with the outer, larger diameter tube of assembly 100. A second tube 108 extends from elbow connector 106 and has it open end at an elevation above core plate 34. A third tube 110 extends from first connector 102 to an elbow connector 112. Third tube 110 is in flow communication with the inner, smaller diameter tube of assembly 100. A fourth tube 114 extends from elbow connector 112 and has its open end at an elevation below core plate 34. Support brackets 116, 118, 120 and 122 are utilized to support tube assembly 100 and tubes 108 and 114 along their lengths. Operation of the core differential pressure and injection apparatus shown in FIG. 2 is substantially the same as operation of the apparatus shown in FIG. 1. In addition, and as explained below, the shortcomings of such apparatus also are similar. FIGS. 3A and 3B illustrate still another known core differential pressure and neutron absorbent injection apparatus. Reactor and apparatus components shown in FIGS. 3A and 3B which are the same as the reactor components shown in FIGS. 1B and 2 are labelled using the same reference numerals in FIGS. 3A and 3B as are used in FIGS. 1B and 2. Referring to FIG. 3A, an opening 38 is formed in reactor pressure vessel wall 22. Tube assembly 150 is inserted into and extends through such opening 38. Tube assembly 150 includes an outer, larger diameter tube having an inner, smaller diameter tube positioned therein. As shown in FIG. 3B, a first tube 152 extends from a u-joint 154 in tube assembly 150 and to an elevation above core plate 34. A second tube 156 also extends from U-joint 154 and to an elevation below core plate 34. First tube 152 is in flow communication with the outer tube of tube assembly 150 and second tube 156 is in flow communication with the inner tube of assembly 150. A number of support brackets 158, 160, 162, 164 and 166 are utilized to support tube assembly 150 and tubes 152 and 156 along their lengths. With respect to the known differential pressure and standby liquid control line apparatus described above, creviced weld connections typically are used to weld the stainless steel tubes to the support brackets. In addition, the tubes are welded to sockets and connectors. The use of such welds, in combination with the high carbon content stainless steel tube material and exposure to the reactor environment, may result in intergranular stress corrosion cracking (IGSCC) of the tubes. Of course, such IGSCC is undesirable in that such IGSCC could lead to a failure of one or both of the tubes. An inaccurate core differential pressure reading, or total loss of the ability to obtain such reading, may adversely affect reactor operation, including even possibly requiring shutting down the reactor to perform repairs. A core differential pressure and liquid control line apparatus 200 which is believed to overcome these and other shortcomings of known apparatus is shown in FIG. 4. Reactor components shown in FIG. 4 which are the same as the reactor components shown in FIGS. 1B, 2 and 3A are labelled using the same reference numerals in FIG. 4 as are used in FIGS. 1B, 2 and 3A. As shown in FIG. 4, the apparatus, or tube assembly 200 including a first tube portion 202 configured to be positioned within and extend through opening 24 in pressure vessel wall 22 and into tee-connector 26. First tube portion 202 has a diameter less than the diameter of the nozzle bore and less than the diameter of opening 24 in pressure vessel wall 22. Tube assembly 200 further includes a second, L-shaped, tube portion 204. A first shrink coupling 206 couples one end of first tube portion 202 to one end of second tube portion 204. Shrink coupling 206 may be a Tinel type coupling, which is generally known in the art. Assembly 200 further includes a third tube portion 208 having one end 210 configured to be positioned at an elevation above core plate 34. Particularly, tube portion 208 extends through opening 36 in core plate 34 so that open end 210 of tube portion 208 is at an elevation of above core plate 34. A second shrink coupling 212 couples second tube portion 204 and third tube portion 208. Second shrink coupling 212 may also be a Tinel type coupling. First, second and third tube portions 202, 204 and 208 are, in one embodiment, stainless steel. At the location of opening 24 in reactor pressure vessel wall 22, an annulus 214 is formed between the exterior surface of first tube portion 202 and pressure vessel wall 22. Tee-connector 26, which is shown as being attached to wall 22, includes a first port in flow communication with first tube portion 202 and a second port in flow communication with annulus 214. Tee-connector 26 may be the same configuration as shown in FIG. 1C. In operation, and to determine core differential pressure, the pressure at an elevation above core plate 34 is communicated through tube assembly 200 to first port 70 of tee-connector 26. The pressure below core plate 34 is communicated through annulus 214 to second port 74 in tee-connector 26. Using such pressures, the core differential pressure can be determined. In comparison to the FIG. 1 configuration, first and second ports 70 and 74 are coupled with apparatus 200 in a reverse fashion. That is, with apparatus 200, first port 70 is in communication with the pressure above core plate 34 and second port 74 is in communication with the pressure below core plate 34. In FIG. 1C, first port 70 is in communication with the pressure below core plate 34 and second port 74 is in communication with the pressure above core plate 34. Therefore, with apparatus 200, it may be necessary to re-route external piping when replacing apparatus 50 (FIG. 1B) with apparatus 200. To inject a neutron absorbent into the vessel below core plate 34 with apparatus 200, such absorbent may be injected through the second port of tee-connector 26 and into annulus 214. Such absorbent will flow through annulus 214 and will be injected into the reactor vessel bottom head at location 216 where annulus 214 opens into the interior of the pressure vessel. The neutron absorbent may, for example, be liquid pentaborate. Although assembly 200 is supported by support brackets 218 and 220 along its length, the likelihood for failures is believed to be reduced as compared to the known apparatus described hereinbefore. Importantly, the tube assembly having a smaller diameter tube inserted within a larger diameter tube is eliminated in assembly 200. In addition, a significant number of welds are eliminated by utilizing apparatus 200. Further, apparatus 200 is believed to be generic in that apparatus 200 can be used to replace the apparatus illustrated in FIGS. 1B, 1C, 1D, 2, 3A and 3B in the event that if a failure is detected in such an apparatus. The replacement methods are described below. For example, to replace a core differential pressure and control line apparatus having an externally attached nozzle as shown in FIGS. 1B and 2A, the following steps would be executed. 1. Remove complete fuel cells to gain access through the core plate at the two closest locations to the core differential pressure lines. PA1 2. Using a cutting tool, cut the lines at the nozzle penetration of the vessel and at all bracket support locations. Prior to the last cut, the line must be held to prevent dropping the line. PA1 3. Remove the pressure line through the core plate hole and out of the vessel. PA1 4. At the location of nozzle penetration inside the vessel, remove any defective material and machine back the inner pipe (if necessary for plug access). PA1 5. Install seal plug at the nozzle opening. PA1 6. Drain the exterior pipes. PA1 7. Cut and remove exterior piping and machine weld preparation onto existing nozzle end. PA1 8. Fitup and weld external pipe assembly with pipe which extends into the vessel. PA1 9. Install spool pipes to the tee of the nozzle to complete exterior line assembly. PA1 10. Remove plug on the inside of the vessel. PA1 11. Install template to determine remaining line length and fitup to supports. PA1 12. Machine the new line length based on template dimensions. PA1 13. Install the new line into the core plate and engage the shrink coupling onto the end of the pipe protruding through the nozzle. PA1 14. Heat coupling to shrink Tinel material onto pipe connection. PA1 15. Install clamp at existing brackets to support the replacement line. PA1 1. Remove complete fuel cells to gain access through the core plate at the two closest locations to the core delta P lines. PA1 2. Using cutting tool, cut the lines at the nozzle penetration of the vessel and at all bracket support locations. Prior to the last cut, the line must be held to prevent dropping the line. PA1 3. Remove the line through the core plate hole and out of the vessel. PA1 4. Install plug onto the outside diameter of the remaining pipe stub in the vessel (this assumes that the pipe connection to the vessel is not completely severed). PA1 5. Drain the exterior pipes. PA1 6. Cut and Remove exterior pipes. PA1 7. Cut piping inside the nozzle penetration up to the weld attachment inside the vessel. PA1 8. Install plug in vessel penetration as necessary to restrict any leakage. PA1 9. Create a weld buildup deposit at the nozzle penetration on the vessel outer diameter using an appropriate temper bead weld process for welding to low alloy steel material. PA1 10. Machine the weld buildup including a weld prep. PA1 11. Fitup and weld external pipe assembly. PA1 12. Remove nozzle ID plug. PA1 13. Insert internal pipe with O-ring on OD to seal to nozzle bore and an ID plug. PA1 14. Weld internal pipe to Tee assembly PA1 15. Fitup and weld exterior piping spool pieces to complete exterior piping system. PA1 16. Remove plugs and seals from inside vessel. PA1 17. Machine off remaining pipe stub inside the vessel and any defects at nozzle opening. PA1 18. Install template to determine remaining line length and fitup to supports. PA1 19. Machine the new length based on template dimensions. PA1 20. Install the new line into the core plate and engage the shrink coupling onto the end of the pipe protruding through the nozzle. PA1 21. Heat coupling to shrink Tinel material onto the pipe connection. PA1 22. Install clamp at existing line brackets to support the replacement line. To replace a core differential pressure and control line apparatus having an internally attached nozzle as shown in FIG. 3A, the following steps would be executed. The core differential pressure and neutron absorbent injection apparatus, as described above, can be utilized to replace a number of known existing core differential pressure and neutron absorbent injection apparatus presently installed in nuclear reactors. In addition, such apparatus reduces the possibility for IGSCC, thereby reducing the possibility for failure of the apparatus. From the preceding description of the present invention, it is evident that the objects of the invention are attained. Although the invention has been described and illustrated in detail, it is to be clearly understood that the same is intended by way of illustration and example only and is not be taken by way of limitation. Accordingly, the spirit and scope of the invention are to be limited only by the terms of the appended claims.
051184648	description	DESCRIPTION OF THE PREFERRED EMBODIMENTS We have discovered that it is possible to create conditions in sizeable gaps, typically 2-10 mils across, such that a standing wave of the proper frequency can be excited in a judiciously chosen gas, or gas mixture. We apply this discovery to permit the nondestructive examination by ultrasound of a boiling water nuclear reactor at a stub-tube from a control rod drive housing through a gas gap to examine the integrity of the welds of the control rod drive housing to the stub-tube and to the heat-affected zones adjacent to those welds. With reference to FIG. 1C, it can be seen that a longitudinal acoustic wave from transducer 40 passes through couplant fluid 31 incident on the sidewall of control rod drive housing H. Thereafter, the ultrasound bridges narrow gap G containing a gas 32. As will hereafter be understood, the wave when it is incident on an interface of gap G will be partially transmitted and partially reflected. This partial transmission and partial reflection will vary with the dimension of gap G, the medium in gap G and the frequency of the sound. Under the proper frequency of sound within medium 32, the partial transmission at one surface of gap G constructively interferes with the partial reflection at the opposite surface of gap G, creating a standing wave in the medium which fills the gap G. This effect occurs when the spatial extent of the standing wave exceeds the dimension of the gap, and the gap width is a half-integral number of wavelengths. The screening effect of the gas gap is thus defeated as a deterrent to NDE inspection of the medium behind it. Referring further to FIG. 1C, wave incidence is shown within the metal to be interrogated at an angle of 45.degree.. This enables the illustrated horizontal flaw to "corner trap" the reflected acoustical signal. This is standard nondestructive ultrasound inspection practice. The reader will understand that this is only one possible angle of incidence having utility. Other angles of incidence can be used. To be effective a pulsed wave train of length larger than the gas gap must be excited, and either normal incidence or oblique incidence can be employed, depending on the frequency used. The theory is simplest for normal incidence of monochromatic sound yielding the following expression for the transmission coefficient at the interface between housing H and stub-tube T. The transmission coefficient T is: EQU T=1/[1+(1/4)*(r-1/r).sup.2 sin.sup.2 2.pi.d/.lambda.] (1) where: .lambda.=sound wavelength d=gap width r=impedance ratio Z.sub.1 /Z.sub.2 This formula shows that for arbitrary values of (d/.lambda.) the transmission coefficient is dominated by the (r-1/r).sup.2 term, when r is not unity. The resulting value of T is consequently very small, indicating a large reflection of energy at the gap interface. This is commonly the case for gas-filled gaps. On the other hand, T is equal to unity from Eq. (1) when: EQU d/.lambda.=n/2; n=1,2,3, . . . (2) indicating complete transmission of energy through the gap with no reflection whatever. Thus, if the gap dimension is any integral multiple of half-wavelength satisfying Eq. (2), transmission occurs. It will be understood that gap G to this extent operates as a filter; reflected waves have the same wavelength. Therefore returning waves also are non-reflected, thereby allowing the scattered waves from a flaw to be detected by the transducer 40. It is clear that when Eq. (2) is satisfied, the impedance ratio, r, drops out of Eq. (1), and the propagation is independent of the impedance of the gas gap. The ultrasonic frequency, f, is related to the wavelength by: EQU f=c/.lambda. (3) for linear media, such as steels and gases. To be useful the frequency should fall in a range for efficient propagation in metals (e.g., steel). Combining Eqs. (2) and (3) yields: EQU f=nc/2d; n=1,2,3 . . . (4) where c is the speed of sound in the gas. Taking n=1 for the moment, it is clear that a judicious choice of gas in the gap of width d allows f in the 2-5 megahertz range to be efficiently propagated in metals. When n is a larger integer, another mode is propagated as a standing wave in the gap, again allowing full transmission, a fact of use in larger gaps. To demonstrate the standing wave effect in various gases, Table 1 has been prepared. Helium, hydrogen, water and dry air are considered as examples, and similar results apply to other gases and mixtures. TABLE 1 ______________________________________ Gap Transmission Frequencies At Normal Incidence For Various Fluids Gap Width for T = 1 Frequency Gas/Liquid (mils) (MHZ) In Gap N = 1 N = 2 N = 3 ______________________________________ 2.010 He 9.5 19.0 28.5 2.247 He 8.5 17.0 25.5 2.547 He 7.5 15.0 22.5 2.938 He 6.5 13.0 19.5 3.820 He 5.0 10.0 15.0 4.775 He 4.0 8.0 12.0 6.367 He 3.0 6.0 9.0 6.945 He 2.75 5.5 8.25 2.016 H.sub.2 12.5 25.0 37.5 2.800 H.sub.2 9.0 18.0 27.0 3.150 H.sub.2 8.0 16.0 24.0 3.600 H.sub.2 7.0 14.0 21.0 4.200 H.sub.2 6.0 12.0 18.0 5.040 H.sub.2 5.0 10.0 15.0 6.300 H.sub.2 4.0 8.0 12.0 6.720 H.sub.2 3.75 7.5 11.25 2.014 Liq.H.sub.2 O 14.5 29.0 43.5 2.336 Liq.H.sub.2 O 12.5 25.0 37.5 2.920 Liq.H.sub.2 O 10.0 20.0 30.0 3.893 Liq.H.sub.2 O 7.5 15.0 22.5 4.867 Liq.H.sub.2 O 6.0 12.0 18.0 5.840 Liq.H.sub.2 O 5.0 10.0 15.0 6.489 Liq.H.sub.2 O 4.5 9.0 13.5 6.871 Liq.H.sub.2 O 4.25 8.5 12.75 2.150 Dry Air 3.00 6.0 9.00 2.580 Dry Air 2.50 5.0 7.50 3.225 Dry Air 2.00 4.0 6.00 4.300 Dry Air 1.50 3.0 4.50 5.160 Dry Air 1.25 2.5 3.75 6.450 Dry Air 1.00 2.0 3.00 6.935 Dry Air 0.93 1.86 2.79 ______________________________________ The objective of this invention is to utilize the implications of Eq. (4) in an embodiment conducive to NDE applications, especially in nuclear power plants, including appropriate means of introducing gases favorable to the propagation of sound in metals for the purpose of detecting anomalies ordinarily inaccessible to ultrasound. A second objective of the instant invention is to enhance the usefulness of ultrasonic inspections and extend the state-of-the-art in those applications heretofore considered inappropriate for NDE. Still a third objective is to provide a method and apparatus for detecting flaws in materials behind and obstructed by reflecting media, or gaps, thereby enhancing safety and reliability of the material component. The invention can further be described with reference to the schematic representation of FIG. 2. This wave path is normally incident to the surface being interrogated; the information received will be relevant to axially aligned defects. The reader will understand that initial access occurs from inside the control rod drive housing H. Control rod drive housing H and stub-tube T are joined by weld J (not shown), which has an axial flaw 35 in the heat-affected zone, which is inaccessible to direct inspection techniques from either the inner or outer tube surfaces. It will be understood that the function of the stub-tube T is to bridge the dissimilar metals and shapes between the vessel V and the control rod drive housing H. By exciting the transducer 40, a longitudinal ultrasonic wave (L-wave) is coupled to the inner surface by couplant 41 (which is here the normal water in the reactor). An L-wave is generated in the control rod drive housing H. At the correct frequency the wave bridges the gap G, and an L-wave is introduced into the stub-tube T, which is reflected at the outer tube surface and impinges on the flaw 35, where it is reflected. The return path of the reflected wave also bridges the gap, and the wave impinges on the transducer 40, where it is detected as a "pulse-echo" signal. A complete understanding of the physics demonstrates that the dimension of the interrogating and reflected wave is important, as shown above. Specifically, a small period of time is required for the first incident wave at the correct frequency to traverse gap G. A portion of this wave is reflected and a portion of this wave is transmitted at the far boundary of the gap G. The wave reflected from the far boundary of the gap G constructivelv interferes with further incident sound waves of the correct frequency. This sets up the required standing wave for the transmission that we use that "bridges" the gap G. Although the creation of this condition is essentially in "real time", it is important to understand that the wave packet must have an adequate spatial dimension to create this standing wave. This must be at least twice the dimension of the gap for the medium contained within the gap. By proper axial positioning of the transducer, a longitudinal tip-diffraction signal is generated, accompanied by a reduced pulse-echo signal. This signal is also detected by the transducer in a distinct time and amplitude relation to the pulse-echo signal. Analysis of these signals allows detection and sizing of the flaw, even though it is located behind what has been until now an "opaque" barrier (i.e., a gas-gap). The reader will further appreciate that the disclosure does not use monochromatic sound - although most analysis for the reflection and transmission of ultrasound at such gaps has been theoretically determined for monochromatic waves. In fact, it may be necessary to "tune" the transducer 40 to receive the most beneficial signal. Such tuning is best done on the frequency of the normally incident waves such as those illustrated in FIG. 2. Returning to FIG. 1C, and in order to facilitate ultrasonic wave propagation in relatively small gaps, helium gas 36 is injected under pressure into the annulus of gap G with flow controlled by regulator 37, gas line 38 and nozzle 39. The air originally in the gap is forced out by the excess helium pressure, and the lighter gas is maintained in the gap G by gravity after a short initial transient. Back diffusion of air is slow and is minimized by continued helium gas bled into the gap. Preferably, a collar 50 is utilized to plug the open bottom of the upwardly closed annulus which comprises gap G. This collar is schematically shown in FIG. 1C. In the application of the boiling water reactor, it will be understood that the gap G between stub-tube T and control rod drive housing H will form an annular cavity. This annular cavity will be closed at the upper end by weld J. After long periods of reactor operation, this annulus will be filled with moist air - usually of unknown water content (or humidity). For this reason, the substitution of gases having known transmission features is desired. It will be understood that the helium introduced under pressure displaces this moist air. Specifically, the light helium will move to the top of the annulus; air will be displaced to the bottom of the annulus. Further, it has been determined that any remaining moist air will have little effect. Further, once the displacement has occurred, diffusion will occur slowly in the narrow confines of gap G. The speed of sound in helium at one atmosphere is about 0.382.times.10.sup.5 in. per sec., whereas in air at one atmosphere, it is 0.129.times.10.sup.5 in. per sec at 0% relative humidity. In many applications relative humidity is a strong variable, which is also eliminated by the introduction of the helium in displacing of the gas. For oblique incidence with n=1, and a nominal gap width of 0.007 in., excellent transmission occurs at a frequency very nearly 2.7 megahertz, well within the preferred frequency window. On the other hand, dry air would require roughly 1.3 megahertz, which is outside the preferred range and subject to significant variability due to uncontrolled water vapor content. The calculations utilized pertain to stainless steel for materials of the control rod drive housing H and the stub-tube T; similar calculations lead to favorable results for other metals. Experimentally, the validity of Eq. (4) was checked by a transmission measurement at normal incidence through the tube walls H and T across the gap G in a model. With only air in the gap G, the transmission was observed to be very poor using peak spectral frequencies of 2.25 and 5 megahertz. With helium injection excellent transmission was achieved at both frequencies for a nominal 0.007 in. gap. The ratio was not exactly 2, as expected, because the gap was slightly non-uniform. Eq. (4) is not exact for oblique incidence, so the proper frequency was determined empirically. Transverse (shear) waves may also be used, although with different propagation paths between the transducer and suspected flaws. Used in conjunction with gap transmission, shear-waves of the proper frequency can enhance the observation of flaws in positions difficult to access directly. Shear-waves, per se, cannot exist in the gas gap, but they are mode-converted from oblique incidence of longitudinal waves at the metal surface and propagate in the metal with lower velocity than longitudinal waves. In some cases detection is more sensitive using shear-waves, because of their lower propagation velocity. According to Eq. (3), for fixed frequency, the wavelength is proportional to sonic velocity. The lower velocity shear waves result in shorter wavelength and, consequently, improved resolution, if they are efficiently propagated in the metal. For various gap sizes other gases and liquids are useful. For example, hydrogen gas has a longitudinal wave velocity of 0.504.times.10.sup.5 in. per sec, and water has a value of 0.584.times.10.sup.5 in. per sec. Clearly, Eq. (4) can be satisfied by a large number of combinations of n, d and c for various fluids in the gap. These combinations with associated modeconversions are also incorporated into this disclosure as diverse embodiments of the novel concept. This is illustrated for normally incident waves in Table 1 for pure fluids and for a helium/air/water mixture in Table 2. TABLE 2 ______________________________________ GAP TRANSMISSION FREQUENCIES AT NORMAL INCIDENCE FOR .8/.16/.04 He/Air/Water Mixture Gap Width for T = 1 Frequency (mils) (MHZ) N = 1 N = 2 N = 3 N = 4 ______________________________________ 2.048 8.5 17.0 25.5 34.0 2.1766 8.5 16.0 24.0 32.0 2.487 7.0 14.0 21.0 28.0 2.902 6.0 12.0 18.0 24.0 3.482 5.0 10.0 15.0 20.0 4.352 4.0 8.0 12.0 16.0 5.803 3.0 6.0 9.0 12.0 6.964 2.25 5.0 7.5 10.0 ______________________________________ NOTE: For 12 mil gap f = 2.902, or 4.352, or 5.803 are equally acceptable. A choice can be made to minimize attenuation in the metal, or to match existing transducers. Similar considerations apply to other frequencies. Hydrogen can be either a fire or explosion hazard. Therefore, the use of helium is preferred. It will be appreciated that in the environment set forth here, the exact dimension of gap G can never be precisely known. Specifically, tolerance of the gap G in the environment here illustrated can vary from metal to metal contact to about 15 mils. This being the case, tuning variation of the wave packet carrier (or central) frequency will be required until an acoustical signal having the proper characteristics for the zone to be inspected is achieved. Fortunately, such tuning can rapidly occur. The reader will understand that we have illustrated a radial crack. Cracks may possess numerous orientations. Therefore, it will be seen that the transducers illustrated in FIGS. 3A and 3B hereafter also produce waves which have varying angles of incidence. This enables inspection of cracks of any angularity. Referring to FIG. 3A, an acoustical inspection utilizing the technique of this invention is shown underway. A circular acoustical head 40 is shown manipulated by a shaft 80 through a centering piece P on the top of a control rod drive housing H. Typically, such manipulation occurs from the top of the refueling bridge (not shown) when the reactor undergoes an outage. Alternatively, inspection can occur from below utilizing a seal 85 and a shaft 81; in this latter case entry will be made from below the reactor vessel V (See FIG. 1A). As is well known, utilizing the water moderator surrounding the reactor as the couplant fluid, acoustical signals for interrogating the integrity of the control rod drive housing H occur. Referring to FIG. 3B, the direction of interrogation within the control rod drive housing H and the stub-tube T is illustrated. The reader will understand that the direction of the acoustical interrogations shown are schematic to the interrogation of the steel only; it will be understood that the refraction that occurs from the water couplant fluid to the steel in accordance with Snell's Law is not shown in the perspective of FIG. 3B. Referring to FIG. 3B, a first transducer 63 makes interrogation normally to the side walls of the control rod drive housing H and the stub-tube T. This interrogation being schematically shown at 64. Second transducer 65 makes interrogation at two 45.degree. angles in a plane including the axis of shaft 80 and the radius of the acoustical housing 40 at transducer 65. Described from the plane of the acoustical housing 40, acoustical interrogation occurs 45.degree. upwardly at vector 67 and 45.degree. downward at vector 66. Finally, transducer 68 interrogates in what may be characterized as an upward counterclockwise vector 69 and a downward clockwise vector 70. Utilizing the acoustical examination of vector 67, it will be seen that vector 69 is rotated 45.degree. counterclockwise; utilizing the acoustical examination of vector 66, it will be seen that vector 70 is rotated 45.degree. clockwise. Referring to FIG. 4, a prior art schematic of acoustical testing apparatus suitable for use with this invention is illustrated. A power supply 100 outputs to a pulser circuit 101 which transmits to the transducers 63, 65, or 68 (not shown) in transducer head 40. Returned sound is received at receiver-amplifier circuit 110 and displayed at oscilloscope O. As is conventional, clock 114 outputs to sweep circuit 112 with marker circuit 116 being utilized for the precise measurement of the displayed pulses. Referring to FIG. 5A, a plot of a typical acoustical signal with respect to time t is shown. The pulse width PW is labeled. It is to be understood that this pulse width PW, with respect to the speed of sound in gap G, has a dimension that is at least twice with width of the gap G. This enables the required standing wave to occur. Referring to FIG. 5B, the so-called power spectral density of a Gaussian wave form is illustrated. Specifically, the wave form here has a "bell shaped" curve and is centered on an arbitrary frequency f (See Table 2); other wave forms characteristic of various transducers at varied power spectrums can be used. Frequencies in the illustrated wave packet exist on either side of the median frequency f, it being noted that the width of the packet at the 50% power range is referred to as the bandwidth BW. Looking further at FIG. 5B, we have labeled a small portion of the frequencies at 140. These frequencies are exemplary of that small portion of frequencies that will be transmitted through a gap G of a given dimension. This partial transmission will occur because only that portion of the frequencies that is a half-integer multiple of the gap G dimension will be transmitted across the gap G. It will thus be understood that gap G acts as a filter; it only permits a small fraction of the originally transmitted wave to effect the interrogating penetration. This effect may now be illustrated. Referring to FIG. 6A, a graphic representation of an oscilloscope plot is shown. The plot of FIG. 6A is an acoustical interrogation taken normally to the control rod drive housing H and the stub-tube T. Zero db (decibels) gain has been utilized. The interrogation has occurred at 0.degree. incidence. Wavelengths of 2.5 and 5 Mhz (megaHertz) have been used. The interrogation occurs at location 191 from the control rod drive housing H. Only the control rod drive housing H is interrogated; no part of the stub-tube T is examined (see FIG. 1B). The plot shows the initial pulse followed by multiple reflections from the back wall at 201, 202. It will be understood that the full spectrum transmitted can, in effect, be returned. As is conventional, measurement of wall thickness is proportional to the time difference of the peaks of the illustrated plot of FIG. 6A. Referring to FIG. 6B, interrogation at weld J is illustrated at 192. Such interrogation occurs through the control rod drive housing H, the weld at J, and the stub-tube. An 8 db receiver gain was utilized. Here we see no back wall reflection from the control rod drive housing H. Displacement is larger because thickness has increased through the control rod drive housing and stub-tube as well as the mutually penetrating weld J. The illustrated peak 206 occurs from the boundary of the stub-tube T. Interrogation at 193 is exemplary of the invention herein. The plot of this penetration is similar to FIG. 6B except that transmission is through the gap. As set forth in the plot of FIG. 6C, considerable attenuation of the wave packet has occurred. Consequently, the receiver has a 44 db gain. There are considerable losses due to the fact that the transmitted waves across gap G only permit a small part of the energy to get through gap G (with 36 db loss). It will be understood that the time sequence of the pulses of FIG. 6B is identical to FIG. 6C. Helium in the gap G is transparent, only the gain is different. This difference in gain is the reflection of the energy at gap G that is off resonance. In the experimental data shown at FIG. 6D, an interrogation was taken at 194. This portion of gap G was believed not to contain helium. Practically no energy was transmitted through the gap G. This plot is illustrated at a gain of 70 db. An actual defect has been found using this technique. This has been done with the 45.degree. incidence shown in FIG. 3B. The defect found constituted machine grooves on the outside of the stub-tube T, an area that was not accessible to ultrasound interrogation of the prior art. It is to be noted that such grooves are analogous to actual crack propagation. Cracks typically propagate from the outside of the stub-tube to and toward the control rod drive housing in the area adjacent to the weld. We have found that size measurement of the detected cracks is also possible. Specifically, the tip of the crack when excited acoustically emanates diffracted acoustical signals. These diffraction signals contain information from which the dimension of the crack can be determined. Diffracted waves also penetrate the gas gap since their frequency is unchanged by the diffraction process. While size measurement is possible, that subject cannot be fully developed here at this time. The consideration of a special case is relevant. Specifically, it may be possible for a crack to penetrate to gap G. In such penetration, gap G will become flooded with helium. It could possibly be that such a gap G could transmit sound rather than reflect sound if it happened to have a proper width. Such a gap G would be transparent to the non-destructive test in the highly unlikely circumstances cited. In actual practice, it is believed that such a condition will not occur to a statistically significant degree. Cracks from intergranular stress corrosion cracking are irregular and of extremely small width compared to gap G--which is always a manufactured gap G. Such small-dimension irregular cracks will have a very high reflectance to the wavelengths disclosed here. It will be understood that the stub-tube T and control rod drive housing example here illustrated is exemplary. The technique here disclosed will extend far beyond this limited environment. Upon analysis, it will be understood that the substance used for filling the gap can be virtually any material. For example, it does not have to be a gas. Water, liquid sodium, or even a plastic could be utilized. Further, all types of normally tested solids may be utilized in some form. The reader will further understand that the signal from a conventional pulsed transducer will have various power spectral densities and bandwidths, these being selected to provide the optimum result. Normally, before an inspection task is undertaken, analysis of the power spectral density and bandwidth against the speed of the ultrasound in the different media through which the sound passes will have to be examined. We disclose the following equations for use in the solution of this problem. __________________________________________________________________________ PULSE WAVEFORM, POWER SPECTRAL DENSITY AND FOURIER TRANSFORM Exemplary Values __________________________________________________________________________ c = .97where c is the sonic velocity in He gas gap (mm/.mu.sec) n = .25where n < 1 is the index of refraction relative to steel for longitudinal waves in the gas ##STR1## d = .002 .multidot. 25.4where d is the gas gap width (mm) m = 1where m is the order of interference (1, 2, 3, 4 . . . ) V1 = .8where V1, V2 are the volume fractions of He and air, respectively, in gap V2 = .2 ##STR2## ##STR3## ##STR4## ##STR5## ##STR6## PW = 1/BWwhere PW is the effective pulse width (.mu.sec) h.sub.i = [a t].sup.2 .multidot. e.sup.-[a.multidot.t].spsp.2 cos[b .multidot. t]where h is the pulse waveform (normalized) ##STR7## ##STR8## ##STR9## G = FFT[h(t)]where G is the normalized fast Fourier transfer of h PSD = .vertline.G.vertline..sup.2 where PSD is the normalized power spectral density for the pulse __________________________________________________________________________ It will be left to those having skill in the art to effect analysis utilizing the disclosed equations for selecting appropriate wave packets from the ultrasound technique here disclosed.
055127592	description	V. DETAILED DESCRIPTION OF THE INVENTION The following terms of art are defined before providing a description and discussion of the present invention. A. Terms of Art Synchrotron Source: X-ray radiation source for accelerating electrons or protons in closed orbits in which the frequency of the accelerating voltage is varied (or held constant in the case of electrons) and the strength of the magnetic field is varied so as to keep the orbit radius constant. Synchrotron Radiation: The delineating electromagnetic radiation generated by the acceleration of charged relativistic particles, usually electrons, in a magnetic field as incident on and producing an illumination field on a mask. The illumination field is characterized by its intensity, direction, divergence, and spectral width. EUV: Extreme Ultra-Violet Radiation, also known as soft x-rays, with wavelength in the range of 50 to 700 .ANG.. 1.times. Camera: A camera of the class disclosed in U.S. Pat. No. 3,748,015. 5.times. Camera: A camera of the class disclosed in U.S. Pat. No. 5,315,629. Spherical Mirror (Powered Mirror): A mirror, either concave or convex, whose surface forms part of a sphere. Although the present invention employs the use of spherical mirrors for convenience and economical concerns, it is intended that other mirrors be covered by the present invention, such as toroidal, conic sections (e.g., parabolic, hyperbolic, elliptical, etc.), mirrors that may be substituted for spherical mirrors within tolerable industry standards (including those with minor flaws or aberrations), etc. Flat Mirror: A mirror whose surface is nearly flat within manufacturing tolerances. Although the present invention employs the use of flat mirrors, it is intended that the present invention be easily modified by those of ordinary skill in the art to employ the use of spherical mirrors where flat mirrors are disclosed in the following discussion. Divergence: As used by itself, the term refers to mask divergence, i.e., the largest angle about the axis of the cone of radiation as incident on a mask. In projection lithography, the axis is generally a few degrees off normal incidence as required for reflection masking. The magnitude of divergence required in projection lithography is that needed to reduce ringing at feature edges to the extent necessary for desired resolution and contrast. In full-field exposure mode, divergence should be similar at every illumination point. In scanning mode, some nonuniformity in the scanning direction may be averaged out. Convergence: As used by itself, the term refers to mask convergence, i.e., the smallest angle about the axis of the cone of radiation as incident on a mask. Condenser: Optical system for collecting the synchrotron radiation, for processing the synchrotron radiation to produce a ringfield illumination field and for illuminating the mask. Collecting Optics (or Collector): The optics within the condenser responsible for collecting the synchrotron radiation. The collector has a focus. Processing Optics: The optics within the condenser, in addition to the collecting optics, responsible for processing collected radiation for delivery to the mask. Imaging Optics (or Camera Optics): The optics following the condenser, in addition to the collecting and processing optics, responsible for delivering mask-modulated radiation to the wafer, i.e., the camera optics. Camera Pupil: Real or virtual aperture that defines the position through which synchrotron radiation must enter the camera, of angular size defining the diffraction limit of the camera. Its physical size is that of an image of the real limiting aperture of the camera. Aperture Stop: The point at which the principal rays cross; the stop serves to fold the ray bundles, i.e., to move the image to the other side of the optics. Lens: The term is used in this description to define any optical element which causes x-ray radiation to converge or diverge. "Lenses," in x-ray systems, are generally reflecting and are sometimes referred to as "mirrors." Contemplated lenses may be multi-faceted or may be non-faceted, i.e., continuous, e.g., of ellipsoidal or other curvature. The convergence or divergence is a result of action analogous to that of a transmission optical lens. Full-field Exposure: Simultaneous (rather than sequential) exposure of all subareas of an image field. In its derivation, the term refers generally to a complete circuit pattern such as that of an entire chip. In this description, it is used to refer to any low-aspect ratio rectilinear pattern region, whether of an entire or partial pattern. Contemplated partial patterns may be stitched together by step-and-repeat to constitute the entire pattern. B. The Invention The present invention makes effective use of x-ray synchrotron radiation, collected over a large emission arc for use in illuminating a pattern mask. The arc is at least 100 mrad, or preferably 200 mrad, to a full radian or more. Pattern delineation to which the radiation is to be applied may take a variety of forms. It may take the form of full-field exposure or of a scanning (e.g., ringfield) region. Exposure may be by proximity printing or by projection lithography. A favored form of projection lithography, known as ringfield projection lithography, makes use of a scanning region of arcuate shape, likely with object:image size reduction, perhaps by a ratio of 5:1, to permit use of more economical, larger-feature masks. Synchrotron radiation is not well adapted to satisfy either ringfield scanning or full-field exposure needs. Synchrotron radiation is shown in FIG. 1. As the high speed electrons within beam (10) follow a curved path (11), they emit a fan shape of electromagnetic radiation (12) in a horizontal plane, also referred to as synchrotron emission light. The photon energy is determined by the electron energy and by the curvature of the electron path. Electron energies of 5.times.10.sup.8 to 1.times.10.sup.9 are useful for x-ray radiation at the 5 to 150 .ANG. wavelength range of interest (for synchrotron devices in present use). The emitted radiation fan is very thin, perhaps 1 mm thick, spreading to a thickness of a few millimeters at a distance of several meters from the synchrotron source. The angle of the emission fan is the same as that of the bent emitting path. Because synchrotron radiation has a high degree of coherence, it is possible to capture all the radiation emitted, with any losses coming only from the finite reflectivity of the mirrors employed in the condenser design. C. The Condenser The condenser of the present invention provides for collection of a large arc of the synchrotron radiation by use of a plurality of spherical mirrors arranged in a series (Six beams of synchrotron light and six beams of light and six sets of mirrors are shown in FIGS. 3 and 5 for convenience in introducing the invention. The figures will be discussed infra with respect to the reference numerals.) to collect the synchrotron light, and a plurality of flat mirrors follow the spherical mirrors to process the synchrotron light. Following the flat mirrors are optics comprising flat mirrors located in the same plane as the real entrance pupil of the camera and directs the beams toward the ringfield of the camera. Following the flat mirrors is a spherical mirror that projects the image formed at the real entrance pupil through the resistive mask and into the virtual entrance pupil of the camera. The condenser optics are located intermediate to the synchrotron source and the ringfield camera. For convenience in introducing the invention, the following discussion is generally in terms of the single elements that collect and process a single beam of synchrotron light. Even though depicted as single elements, however, two or more elements may be combined for a given change in beam direction. Also, any number of beams may be collected depending on the power to be collected from the synchrotron source, which would require a corresponding set of (six) mirrors for each beam to be collected, processed, and imaged. In a preferred embodiment, the condenser system comprises, from synchrotron source plane to image (the wafer) plane, at least two spherical mirrors for collecting and shaping a single light beam, wherein the spherical mirrors comprises a first mirror that is concave and a second mirror that is convex. The first and second spherical mirrors are tilted for collecting and transforming the light beam into an arc-shaped light beam. The resulting arc-shaped light beam fits the ringfield of the camera. A third mirror, following the second mirror and shown in FIG. 4 (discussed in detail infra), is a flat mirror for rotating and directing the light into a real entrance pupil of a ringfield camera. A fourth mirror, following the third mirror, is a flat mirror also for rotating and directing the light into a real entrance pupil of a ringfield camera. A fifth mirror, following the fourth mirror, is a flat mirror. It is located at the real entrance pupil of the camera and is individually tilted to make all the light beams substantially parallel to each other when more than one beam is collected. The fifth mirror directs the beam(s) toward the ringfield of a camera. A sixth mirror, following the fifth mirror, is common to all of the beam(s) emitted from the preceding mirror sets and is a spherical mirror. The sixth mirror images the beams located at the real entrance pupil through the resistive mask and into the virtual entrance pupil of the camera. The sixth mirror also serves to converge the six beams at the mask plane. Thus, the condenser is comprised of a plurality of beams with five mirrors corresponding to a single beam plus one mirror that is common to the plurality of beams. In an alternate embodiment, the third and fourth mirrors could be combined to use only one flat mirror, provided the first and second mirror are positioned accordingly as shown in FIGS. 8 and 9. The design and function of this alternate embodiment is equivalent to the design and function of the preferred embodiment discussed supra with the exception of the use of fewer processing mirrors. Thus, the discussion of the preferred embodiment applies to this alternate embodiment. Referring to FIG. 8, as in the preferred embodiment, the first mirror (84) is a concave spherical mirror, the second mirror (85) is a convex spherical mirror. The third mirror (86) is substituted for the combined function of the third and fourth mirrors in the preferred embodiment. Referring now to FIG. 9, the first mirror (94), which is concave, is positioned below the second mirror (95), which is convex. The first (94) and second (95) mirrors collect the light beams and translate them into arc-shaped beams. The third mirror (96), which is flat, receives a converging beam from the second mirror and processes the beams. The condenser is then comprised of a plurality of beams with four mirrors corresponding to a single beam plus one mirror that is common to the plurality of beams. Optional, airtight valves (89) preserve vacuum in the synchrotron. All of the optics discussed are flat mirrors or long-F/no. spherical mirrors. The plurality of arc images all have a common orientation at the curved slit of the camera. The third mirror in the set can be moved axially to focus the arc image in the camera's entrance slit. The tilt of the fifth mirror allows the arc image to be pointed into the slit. The magnification of the arc image could be changed by a small amount by playing off the individual beam image positions and the distance from the camera and the fifth mirror. The image quality realized by the present invention is adequate to illuminate any ringfield with a width of W.gtoreq.100 .mu.m. The transmission efficiency .eta. of the complete system is equal to the product of the six mirror reflectivities in each set of mirrors. There are three mirrors that are tilted (approximately 45.degree.) in orientation (S-polarization), two near-normal mirrors, and the fourth mirror could be set at grazing incidence (not shown in the figures). The radiation from the synchrotron is horizontally polarized, which is the "S-polarization" for all of the tilted (e.g., 45.degree.) mirrors. Partial coherence in the illumination affects the image quality. For the small design features sought by the EUVL system, it is important that the condenser provide uniform, partial coherence illumination properties along the ringfield. In an incoherently illuminated optical system, small features are attenuated due to the fall-off of the modulation transfer function ("MTF"). Partial coherence can be introduced into the illumination to counter this attenuation. This is normally accomplished by underfilling the entrance pupil in a system with Kohler illumination. In other words, the source (which is usually a disk) is imaged into the entrance pupil, and this image is smaller than the pupil by a partial coherence factor of .sigma..apprxeq.0.6. This value of .sigma. is a reasonable compromise, which amplifies the smaller features and does not add too much "ringing" to the larger features. The partial coherence factor .sigma. could be in the range of 0.5>.sigma.>0.65. The entrance pupil illumination for this embodiment is shown in FIG. 7, which shows an end view of the six light beams (73) in the same plane as that of the real entrance pupil (70) of the ringfield camera. The flat mirrors (71) and (72) serve to focus the light beams coming from the fourth mirrors into the real entrance pupil (70) of the camera. The six flat mirrors (71) and (72) are arbitrarily located, for example, 1 m in front of the real entrance pupil of the camera. Five light beams (73) are received by five flat mirrors (71) that are arranged in a symmetrical pattern about a single flat mirror (72) that receives a sixth beam (74) at the real entrance pupil (70) of the camera. Illustrative work discussed in detail provides for collection over a full radian (.about.57.degree.) of synchrotron radiation. This two-order-of-magnitude increase in collection angle increases wafer throughput or productivity. Specific needs are met by a variety of arrangements. One of the primary advances herein is the ability to illuminate a narrow ringfield of a camera by forming and focusing arc-shaped light beams into the entrance pupil of the camera, thus maximizing the collection efficiency of the condenser. Collected radiation may be reassembled in proximity printing to yield a scanning slit; or alternatively, to yield an illumination region of small aspect ratio for full-field patterning. The present invention provides for scanning (e.g., ringfield) or full-field projection. The specific description that follows emphasizes ringfield projection lithography. Where fall-field exposure, either proximity printing or projection lithography, requires different optics, notation is made in the final discussion in each section. The significant case of ringfield projection lithography is represented by FIG. 2. In FIG. 2, the resistive mask (20) includes a rectilinear patterned region (21), which is being swept horizontally in direction (23) by an arc-shaped illumination region (22) which may be 1 to 8 mm wide by about 130 mm long. The energy from the condenser must illuminate only region (22) and no other part of region (21). In full-field exposure (as distinguished from the scanning shown) pattern region (22) and region (21) must be simultaneously illuminated. 1. The Collecting Optics The collecting optics, or collector, of the condenser system are comprised of at least two spherical mirrors, a first mirror that is concave and a second mirror that is convex, positioned symmetrically about the periphery of the synchrotron source. It is expected that at least arc of collection will be 100 mrad, likely from 200 mrad to 1.5 rad. Collection over a radian for a synchrotron of radius of 1 to 2 m may require a collector length of the order of a meter. The collector length may be accommodated by using a plurality of parallel channel systems comprised of approximately 15 cm class mirrors. The distance from the collector to the synchrotron orbit is typically 1 to 3 m, but could be varied. A shorter distance may require a greater angle of incidence on the first mirror of the condenser, which would reduce the flux on the mirror. A longer distance may require collector lenses of excessive size. The spectrum of the synchrotron emission light is broad. It is desirably tailored to meet particular needs. In projection lithography, a wavelength range of .lambda.=120 to 140 .ANG. takes advantage of most efficient reflectivity (of both lenses and mask). In proximity printing, a shorter wavelength in the range of .lambda. is=8 to 16 .ANG. is required for resolution and meets characteristics of available resists. Efficient operation of the condenser is aided by spectral narrowing, minimizing unwanted heating caused by radiation which is relatively ineffective for resist exposure. The use of multi-layer mirrors in the condenser of the present invention accomplishes the spectral narrowing. In a preferred embodiment, all of the mirrors of the condenser are multi-layer mirrors. The relatively long wavelength radiation of EUVL also permits use of glancing-angle lenses with relatively large angles of incidence. Glancing-angles lenses may inherently produce some spectral narrowing. When operating at or near the critical angle for the desired radiation wavelength, shorter wavelength radiation is not reflected. A condenser should be able to capture several watts of radiation in the pass band of a ringfield camera and deliver over a watt to the mask, which is enough power to expose resist coated wafers at a rate of several square centimeters per second. A typical ringfield camera pass band may be 130.+-.1.3 .ANG.. This pass band is determined by present multi-layer mirror technology. U.S. Pat. No. 5,315,629 is illustrative of a state-of-the-art ringfield projection camera. A reflectivity of 60 to 65% results from use of 40 successive Mo--Si layer pairs. Soft x-ray is also favored for surface reflection off certain metal mirrors. Angles of incidence of 5.degree. to 10.degree. from grazing incidence may result in reflectivity of 80 to 90%. A plurality of pairs of spherical mirrors, a first mirror that is concave and a second mirror that is convex, are sequentially placed about the synchrotron orbit as shown in FIG. 3 to produce an illumination field. The Etendu or Lagrange Optical Invariant requires that the product of convergence angle, .THETA., and the corresponding focus dimension equal or exceed the same product at the mask if a dispersing element (e.g., a scatter plate) is to be avoided as in the present invention. FIG. 3 is a top view of the optics of the complete condenser system near the synchrotron source and is illustrative in providing for a plurality of collector lenses (34) and (35), which are nominally spherical mirrors. Each mirror receives x-rays from a related spot in the orbital path of the synchrotron beam (30), and each mirror directs its reflected x-ray into focus. Synchrotron beam (30) in following curved path (31) emits a fan of radiation (32), considered as the composite of x-rays (33) produced by point sources within the arc of the synchrotron source. The fan of radiation (32) is collected by collector mirrors (34) and (35), which directs the light beams in a configuration to uniformly illuminate a ringfield of a projection lithography camera. The fan of x-rays (32) is shaped into arc-shaped beams by second mirror (35) of the collecting optics. A preferred structure for ringfield reduction projection may use six or more sets of mirrors for six light beams as shown in FIG. 3, depending upon the power to be collected from the synchrotron source. Optional, airtight valves (39) preserve vacuum in the synchrotron. In FIG. 3, the first mirror (34) in each set (corresponding to a single beam) collects a 3.5.degree. section of the synchrotron emission light beam with its coma-like aberration and translates it into a round spot. The first mirror (34) is nominally spherical and is tilted, for example, 9.5.degree. in the horizontal plane. It is arbitrarily located, for example, at a distance of 3 m from the ringfield along a tangent. The ends of the collected arc of radiation are slightly defocused, making the round spot 9% larger than would be expected. This small variation is negligible because the light beam is probably smaller than 1 mm. The round spot image radiates into a solid angle described by a small vertical angle and a large horizontal angle, similar to the 3.5.degree. section of the synchrotron emission light. The power radiated (from the spot) per unit of horizontal angle is constant, just as is the radiation exiting the synchrotron. Hence, at a distance from the spot it will form a line constant power along its length. The second mirror (35) translates the beam's straight line cross-section into an arc cross-section so that it will fit into the ringfield of the camera. FIG. 4 is a side view of the first four mirrors in the set of mirrors showing that second mirror (45) directs the beam upwards (e.g., angle of incidence i=48.4.degree.); a result that is corrected by the following third mirror (46), which is flat (discussed below under The Processing Optics). Second mirror (45) is arbitrarily located, for example, at 500 mm from first mirror (44) but must be placed a few millimeters lower than the fan of radiation (32) emitted from the synchrotron. In a preferred embodiment, the second mirror (45) is designed to have a back focal distance of BFD=10 m, for this particular geometry, to enable the projection of an image of the spot into the real entrance pupil of the camera. The focus of the collector may correspond with a real aperture of the camera, or it may itself define a virtual aperture of the camera. Adjustability of a real aperture is useful in obtaining a desired pupil fill. 2. The Processing Optics The condenser further comprises processing optics for matching the characteristics of the ringfield camera. Characteristically, a projection reduction camera operates with a divergence of 5 to 15 mrad. Shape and size of the imaging region, again the responsibility of the processing optics, varies with the camera design. Referring to FIG. 4, the correcting, third mirror (46) turns the beam back into the horizontal plane (e.g., i=41.6.degree.) and almost parallel to the beam between the first mirror (44) and the second mirror (45). Thus, the third mirror (46) orients the cross-section of the beam's arc so the center is horizontal. All of the beams collected from the synchrotron are subject to the same manipulation, therefore, their arcs' cross-sections can be overlapped at the ringfield. The fourth mirror (47) is near-normal and flat. The fourth mirror (47) directs the beams toward the fifth mirror (58) as shown in FIG. 5. The fifth mirror (58) is located at the real entrance pupil (55) of the camera (51). The fifth mirror (58) is tilted to direct the beams toward spherical mirror (59). The fourth mirror (47) of FIG. 4 turns the beam in a horizontal plane so that the image remains "horizontal." The spacing between the third mirror (46) and the fourth mirror (47) may be selected so as to "focus" the round image at the real entrance pupil. If the fourth mirror (47) could be oriented at grazing incidence, then the grazing angle would vary by at least 10.degree., beam to beam. Therefore, the reflectances would vary by 15 to 20%. In a configuration where a plurality of beams are to be processed, the fifth mirrors (58) could be arranged in a symmetrical pattern, such as the pentagonal pattern shown in FIG. 7, at the real entrance pupil of the camera. The fifth mirrors shown in FIG. 7 are arranged in a symmetrical, pentagonal pattern with five of the mirrors (71) arranged around a centrally disposed single mirror (72). Referring to FIG. 5, the fifth mirrors (58) operate to turn the beams downward (e.g., i.apprxeq.55.degree.) and point them toward the image of the mask as seen behind the sixth mirror which is located at the ringfield (52). In the horizontal plane, the centerlines of the beams emitted from the fifth mirrors all converge toward a common point at the ringfield (52) on the mask plane due to the individual tilting of the fifth mirrors. Also, the input beams to the sixth mirror are nearly horizontal. FIG. 6 illustrates an end view of one proposed beam configuration at the real entrance pupil (60) of the camera. Five of the beams (61) are arranged in a symmetrical pattern about a single beam (62). The illumination region must be directed into the virtual entrance pupil of the camera to the proper degree of fill. Fractional filling, e.g., pupil fill, optimizes contrast for a range of feature sizes. 3. The Imaging Optics The sixth mirror (59) shown in FIG. 5, which is spherical, is common to all beam lines. It images the light beams from the real entrance pupil (54) through the resistive mask (52) and into the virtual entrance pupil of the camera (not shown). The real entrance pupil (54) is created by the fifth mirrors (58), which is an image of the actual real pupil (57) of the camera (51). The real entrance pupil is located one focal length away, so the virtual entrance pupil is projected to infinity. The distance between the sixth mirror (59) and the resistive mask is selected such that the arc image departing second mirror (45) is imaged into the ringfield of the camera. All of the arc-shaped beams collected are overlapped onto the mask by the imaging optics. The collecting and processing optics of the condenser collects a plurality of x-ray beams that are emitted from the synchrotron source and combines them in, for example, a symmetrical, circular pattern at the real entrance pupil of a ringfield camera as shown in FIG. 7. (In the interest of clarifying the present invention, FIG. 7 depicts six light beams, but any number of light beams are possible, depending upon the power to be collected and the image quality desired.) One of the six beams could be positioned in the center with the remaining five beams symmetrically located about the centered, beam. The present invention provides nearly uniform coherence properties for features on the mask oriented at any angle (angles measured in the r-.THETA. plane). All six light beams are received by flat mirrors positioned at the real entrance pupil and imaged through the resistive mask and into the virtual entrance pupil of the camera. The entire arc of the camera is illuminated with each of the six beams to ensure uniform illumination and coherence along the length of the arc. With efficient design there is no clean line of separation between the collecting optics and the processing optics. The collector itself functions as processing optics to the extent that collectors are designed to direct, shape, or otherwise define the illumination region and to the extent that the collector goes beyond focusing collected radiation. The collector may increase divergence and may shape the illumination field. In most projection systems, separate processing optics is preferred, if only to avoid undue complexity in the collector design. Processing lenses may be tilted (e.g., 45.degree.) mirrors. In an alternative embodiment of the present invention, the substituting a single flat mirror for the third and fourth flat mirrors (described above) provided the first and second mirrors are positioned accordingly as illustrated in FIGS. 8 and 9. This embodiment accomplished the same result with less mirrors in the condenser system. Minimal processing is required in proximity printing. FIG. 3 illustrates a condenser for use in full-field proximity printing. U.S. Pat. No. 5,315,629 is illustrative of state-of-the-art ringfield projection lithography. It is contemplated that the system may experience temporal coherence between the six beams. If so, then the coherence could be eliminated by moving a mirror in each set of mirrors, corresponding to a single beam, perpendicular to its normal. This could be accomplished with the use of piezoelectric drivers, each oscillating at a different frequency. a. Example 1 The particular values and configurations discussed in this Example 1 can be varied and are cited merely to illustrate a particular embodiment, and are not intended to limit the scope of the invention. In this Example 1, the condenser coupled light from a 24.degree. sector of the synchrotron emission light into the ringfield of a 1.times. Offner lithography camera positioned in a vertical orientation. The condenser was configured to capture six beams of synchrotron emission light as exemplary shown in FIG. 3. The condenser system was configured to collect synchrotron emission light at a preferred wavelength of .lambda.=134 .ANG.. Collection of the light was made difficult due to the fact that the six beams to be collected spread out in a fan shape. Furthermore, collection was difficult because the Lagrange Optical Invariant for the 1.times. camera is relatively small (in comparison to, for example, a 5.times. camera). The ringfield width of the 1.times. camera is relatively narrow (again, in comparison to, for example, the ringfield width of a 5.times. camera (W.sub.1x =100 .mu.m while W.sub.5x =1 mm)). The camera's numerical aperture was assumed to be n.a..sub.1x =0.08, and a 1 cm length of the arc was illuminated, on a 50 mm radius. The entrance pupil of the camera had a diameter of 133 mm. The collecting optics collected a 3.5.degree. segment of the fan of synchrotron emission light and converted each of the six segments into six arc-shaped beams of light. The first (concave) mirror was spaced apart 3 m from the tangent of the source. It had an angle of incidence i=9.8.degree.. The first (concave) mirrors and second (convex) mirrors were arbitrarily spaced apart by 500 mm. The second (convex) mirrors had an angle of incidence i=48.degree.. Following each of the second mirrors in each of the six pairs, were six third (flat) mirrors and fourth (flat) mirrors comprised of six near normal flat mirrors for rotating and directing each of the six beams toward the real entrance pupil of the camera where they were received by six flat mirrors arranged in a symmetrical, circular pattern (as shown in FIG. 7). The distance between the second (convex) mirrors and the third (flat) mirrors was about 500 mm. The vertical focus was located 2 meters downstream, and the horizontal focus was located 10 meters downstream. The curved vertical "focus" was imaged into the camera's real entrance pupil. The fifth (flat) mirrors, which were .apprxeq.45.degree. mirrors (.apprxeq.17.times.10 mm), were located adjacent to the real entrance pupil of the camera, about 1 m away from the real entrance pupil, and were individually tilted to make all six beams substantially parallel to each other and to direct all six light beams up into the camera, which was vertically-oriented. The six beams received at the real entrance pupil of the camera each had a diameter of about 5 mm. Finally, the beams were received by a sixth, spherical (concave) mirror that imaged the arc images through the mask and into the camera's curved entrance slit. As discussed earlier, the system's transmission efficiency .eta. is a function of the reflectivity of the mirrors. The three near-normal mirrors had reflectivities of R.apprxeq.63%. The two 45.degree. mirrors had reflectivities of R.gtoreq.67%. The condenser system also included a grazing-incidence mirror (not shown) with a reflectivity of R.apprxeq.90%. The efficiency for the condenser system, therefore, is equal to the product of the six mirror reflectivities in each series of mirrors as follows: .eta.=(0.67).sup.3 (0.63).sup.2 (0.9)=10.74%. Other variations and modifications of the present invention will be apparent to those of ordinary skill in the art, and it is the intent of the appended claims that such variations and modifications be covered. For example, a one-beam system could be used to simulate the six-beam final configurations illustrated by tilting the third (flat) mirror (36) in the set of mirrors of FIG. 3 to move the beam around in the entrance pupil and by tilting one of the subsequent mirrors in the chain to compensate for the tilt introduced by the third mirror. The tilt angles would be approximately 3 mrad. Also, scan simulation would have to be performed to provide uniform illumination across the 100 .mu.m wide entrance slit. Furthermore, the configuration could be modified to collect a 50.degree. to 60.degree. fan of radiation. The particular values and configurations discussed above can be varied and are cited merely to illustrate a particular embodiment of the present invention and are not intended to limit the scope of the present invention. It is contemplated that the use of the present invention may involve components having different characteristics as long as the principle, the presentation of a condenser that collects light from a synchrotron source and directs the light into the ringfield of a camera, is followed. It is intended that the scope of the present invention be defined by the claims appended hereto. The entire disclosures of all references, patents, and publications cited herein are hereby incorporated by reference.
047476451	summary	The present invention relates to apparatus to test resistance against the influences of light and weathering on samples of goods, such as paint, fabrics, or other material, and more particularly to provide an apparatus which can accurately reproduce spectral conditions under controlled circumstances, for example simulating sunlight with controlled ultraviolet (UV) and infrared (IR) components, that is, sunlight which might occur under various atmospheric conditions and geographic locations, e.g., at sea level, high altitudes, or the like. BACKGROUND The Assignee of the present application is the manufacturer of a rapid illumination and weather testing apparatus trademarked "Xenotest 1,200".RTM., and described, for example, in literature material D310 561/681. The apparatus permits checking of various and highly different materials with respect to resistance to fading due to light and weather, or other environmental effects. For example, paints, lacquers and varnishes can be tested with respect to color fidelity and maintenance, and also with respect to their mechanical and overall technological behavior. The apparatus has an illumination device with three radiation sectors, which include selectively reflective mirrors, reflecting UV radiation, and being transparent to IR radiation. The selective mirrors extend radially from a common axis outwardly, separating the respective sectors. A IR absorber is located between two each of selectively reflective mirrors of adjacent sectors. Each one of the three sectors has a xenon radiation source associated therewith to provide the required radiation. This filter-radiation arrangement is surrounded by a quartz inner cylinder with a selectively reflective layer for IR radiation, but passing UV and visible spectral components. A water jacket follows the inner cylinder. The water jacket absorbs long wavelength IR radiation. A quartz outer cylinder, and, eventually, a jacket made of UV special, or window glass, surrounds the structure. The filter system provides radiation with an energy distribution which very closely matches that of the radiation derived from sunlight. The filtering system largely filters undesired IR components by absorption, and permits passage, selectively, in the short-wave region of a high proportion of radiation to reach the test samples located about the illumination source. U.S Pat. No. 3,686,940, Kockott, the disclosure of which is incorporated by reference herein and which patent is assigned to an associated organization of the Assignee of the present application, describes a testing apparatus with selective mirrors for removing infrared radiation. The structure has a plurality of eccentrically located radiation sources. A cylindrical mirror is provided which selectively reflects the IR component of the radiation, but is transparent for visible and UV spectral components. Mirrors which are selectively reflective for visible and UV components of the radiation, but passing IR components, are located between the radiation source and the cylindrical mirror. This arrangement permits elimination of short-wave IR radiation, which cause heat, without essentially attenuating the UV radiation. It has been found that some IR filters, and particularly KG filters, that is, heat absorption filters, when also subjected to UV radiation, change their filtering characteristics. Such filters are particularly desirable and useful to test for resistance to fading, and light effects. These filters have the tendency to change their filtering limit in the UV region towards longer wavelength to such an extent that the desired radiation spectrum is undesirably influenced thereby. The change of the UV limitation is also referred to as aging of the filter. OBJECT OF THE INVENTION It is an object to provide a light and weathering resistance test apparatus, particularly to test articles with respect to their resistance to UV and visible spectral light, approaching sunlight, which permits precise adjustment of the respective spectral components and more particularly of IR and UV spectral components and the proportion of visible light within the radiation spectrum. The adjustment should be stable, not subject to change due to aging or the radiation from the source itself. The arrangement should provide a test spectrum for the samples to be tested which matches, as closely as possible, sunlight radiation or a selected spectral distribution, with high efficiency, and with minimum losses due to absorption or reflection. SUMMARY OF THE INVENTION Briefly, IR filters, UV filters and UV mirrors are used. Special IR mirrors, which are usual in illumination systems of this type are not needed, however. A central light source emits radiation in the UV, visible and IR spectral ranges. A sample is positioned, spaced from the central light source in the path of radiation therefrom. The radiation impinging on the sample is controlled by a plurality of UV mirrors, reflecting UV radiation without, essentially, passing UV radiation therethrough, that is, they have a high reflectivity efficiency. At least one UV filter is provided, passing UV radiation and at least one IR filter, passing IR radiation. The region surrounding the light source is subdivided into sectors. In accordance with the invention, a UV filter is located in a first sector and forming a first outer filter; a first mirror-filter combination formed of the first UV mirror having a mirror surface directed towards the light source and an IR filter, essentially congruent with the UV mirror, is provided, the IR filter of the first mirror-filter combination forming a second outer filter. A second mirror-filter combination, and including an essentially congruent sandwich formed by an inner UV mirror having its mirror surface directed towards the light source, an outer UV mirror having its mirror surface directed towards the outer filters, and a IR filter located between the inner and the outer UV mirrors is so located that it places the UV first outer filter entirely within its optical shadow with respect to radiation from the radiation source. The second mirror-filter combination is located spaced from the first mirror-filter combination and positioned between the light source and the first mirror, to direct UV radiation and light to the first UV filter of the first sector. The first UV filter of the first sector thereby forms a radiation window for UV radiation reflected within the spectral control structure from the source, while separating UV radiation from the IR filters, thereby preventing the IR filters from deteriorating under UV light thereon, and preventing aging of the IR filters. The system has the advantage that a precisely defined radiation spectrum can be obtained with IR filters, UV filters, and UV mirrors, without, however, requiring IR mirrors and without subjecting IR filters to UV radiation so that the IR filters will not age. The UV filters, referred to in the present specification, are UV limit filters which, in the UV range, have a steep, essentially stable cutoff flank, while being transparent to radiation up to a wavelength of about 2000 nm, that is, they are also transparent for IR radiation. UV mirrors, as used in the present specification, are reflective mirrors which reflect radiation in the UV range of from about 250 to 400 nm; above, and partially below the mirror reflective range, they are transparent to radiation.
047568720	claims	1. A nuclear power station for a gas-cooled high temperature pebble bed reactor comprising: a prestressed concrete pressure vessel with a pressure containment liner housing a pebble bed reactor, an operating cooling circuit comprising at least one steam generator and blower, a secondary cooling circuit, cooling medium flow through said reactor core from top to bottom within said pressure vessel, at least one reactor shutdown system; a linerless reactor protection building surrounding said prestressed concrete vessel and said cooling circuits, means for relieving pressure in said reactor protection building, means for filtering radioactive contaminants in said reactor protection building in combination with said means for relieving pressure, a plurality of auxiliary cooling circuits separate and independent from said operating and secondary cooling circuits, and means for removal of decay heat of said reactor core in the event of failure of said auxiliary cooling circuits, said means including a prestressed concrete pressure vessel liner cooling circuit. 2. The nuclear power station of claim 1, wherein said means for relieving pressure comprise temperature and pressure control devices. 3. The nuclear power station of claim 1, wherein said means for relieving the pressure of said reactor protection building are connected with relief paths, which open automatically when a certain pressure is exceeded and close when the pressure drops below the actuating pressure. 4. The nuclear power station of claim 1, wherein two separate auxiliary cooling systems are provided, one of said auxiliary cooling systems being sufficient for the removal of the decay heat in the event of accidents without the loss of coolant. 5. The nuclear power station of claim 1, wherein said means for removal of decay heat is the natural convection of said decay heat into the liner cooling circuit. 6. The nuclear power station of claim 1, wherein said means for removal of decay heat is by radiation and conduction into the liner cooling circuit.
041609271	description	DETAILED DESCRIPTION OF THE INENTION While the present invention is directed to a battery utilizing a radioactively ionized ferroelectric ceramic substrate, the behavior and theory of this device is closely related to the device which is illustrated in FIG. 1, which uses a ferroelectric ceramic which is not radioactively ionized, but which produces a voltage upon being irradiated with light. Since more research has been done and more data has been accumulated with respect to the visible light device it will be discussed in some detail before disclosure of the device of the present invention. With reference now initially to FIG. 1 of the application drawings, a discussion of the novel phenomena of the devices will ensue. Upon the application of incident illumination to the ferroelectric ceramic, a steady voltage is produced which is proportional to the length l between the electrodes. By dividing the sample into two equal segments along a line perpendicular to the direction of the remanent polarization and by placing new electrodes on the cut edges, new samples would result each producing photo-emf's which is one half the original photo-emf. An arrangement such as that shown in FIG. 1 can be described roughly by the equivalent circuit as shown in FIG. 2. This has a saturation photo-emf V.sub.o, in series with the photo resistance of the illuminated sample. FIG. 3 is a current-voltage characteristic of a typical illuminated ferroelectric slab, and has the form expected from the equivalent circuit in FIG. 2 except that the slight tendency towards saturation in the lower left quadrant. As a function of intensity, the photo-emf saturates at relatively low levels of illumination. The short circuit photocurrent is, however, linear with light intensity. Results for the material Pb(Zr.sub.0.53, Ti.sub.0.47)O.sub.3 with 1 wt% Nb.sub.2 O.sub.5 are shown in FIG. 4. The implication of these results and the equivalent circuit in FIG. 2 is that the photoresistance R.sub.ph is inversely proportional to intensity. A saturation photo-emf and a short circuit current proportional to intensity has been measured in several poled ferroelectric materials. These are shown in Table I. Table I: __________________________________________________________________________ Photovoltaic outputs at room temperature for several ceramic compositions. The wafers were fully poled, to their maximum remanent polarization. Filtered illumination had a held bandwidth of about 10 nm. The photo-emf is a saturation value reached at relatively low value of intensity. Short Circuit Illumination Saturation Photocurrent Sample Wavelength (nm) Photo-emf (Volts/cm) ##STR1## __________________________________________________________________________ Pb(Zr.sub..53 Ti.sub..47)O.sub.3 + 1 wt% 373 610 .31 Nb.sub.2 O.sub.5 BaTiO.sub.3 + 5 wt% CaTiO.sub.3 403 360 .020 Pb(Zr.sub..65 Ti.sub..35)O.sub.3 with 7% lanthanum-lead substitution 382 1500 .030 Pb(Zr.sub..65 Ti.sub..35)O.sub.3 with 8% lanthanum-lead substitution 382 750 .015 BaTiO.sub.3 +5wt% CaTiO.sub.3 403 355 .02 Pb(Zr.sub..53 Ti.sub..47)O.sub.3 +1wt% Nb.sub.2 O.sub.5 with polished surfaces 382 610 .about..61 __________________________________________________________________________ For a given composition the photo-emf is also a function of grain size. These results are shown in Table II. Table II ______________________________________ Photo-emf for different grain size and percent lanthanum substituted for lead. The materials are Pb(Zr.sub..65 Ti.sub..35)O.sub.3 with 7% lanthanum substitution for lead and the same material with an 8% lanthanum substitution for lead. Percent Lanthanum-Lead Saturation Grain Size Substitution Photo-emf (microns) (percent) (Volts/cm) ______________________________________ 2-4 7 1500 4-6 7 980 greater than 6 7 560 2-4 8 750 3-5 8 510 4-6 8 330 greater than 6 8 250 ______________________________________ The photovoltage v. number of grains per unit length is plotted in FIG. 5 for two different compositions. The plot clearly shows a relationship between the two quantities. The fact that the photo-emf of a particular sample depends on the remanent polarization is shown by the results for a typical ferroelectric material, barium titanate+5wt% CaTiO.sub.3, as plotted in FIG. 6. The short circuit photocurrent depends strongly on the wave length of the impinging illumination. It is a maximum at a wave length resulting in a photon energy equal to the band gap energy of the material. Other wave lengths can, however, contribute strongly to the current. Results for typical materials are shown in FIGS. 7, 8, and 9. The current (ordinate) is that produced by illumination contained in a small band, of about .+-.10 nm about a wave length indicated on the abscissa. A mercury source and notch type dichroic filters were used. The total intensity within each band was only roughly constant. The current that has been plotted has been therefore normalized to constant intensity by assuming the linear relation between the two. The photo-emf is less strongly dependent on wave length. Results for a particular material, using notch dichroic filters is shown in FIG. 10. These values are saturation values, roughly independent of intensity. An important additional phenomena shows a dependence of current produced in the red and infrared regions in the presence of simultaneous blue band gap radiation. These results are shown in FIGS. 11 and 12. The ordinate (FIG. 11) is the current produced by the light from a mercury arc shining through dichroic long wave length cut off filters, the abscissa the wave lengths above which no light illuminates the sample. Note the step at 650 nm. Using short wave length cut off filters which eliminate the band gap light results in no current until the cut off wave length is below the band gap. These results are shown in FIG. 12. The amount of output in the red actually depends on the intensity of simultaneous band gap radiation, thus the energy efficiency of these materials for a broad band source is not simply the intensity weighted average of the efficiencies for individual wave lengths as produced by notch filter. The actual value is larger. Photo-emf vs. cut-off wave length for Pb(Zr.sub.0.53, Ti.sub.0.47)O.sub.3 +1wt% Nb.sub.2 O.sub.3 is shown in FIG. 13. A substantial photo-emf appears at long wave lengths but no current can flow. In other words the internal resistance R.sub.ph is extremely high unless band gap is incident. Single Crystal Results The ceramic results imply a small photo-emf from a single crystal illuminated as shown in FIG. 14. Such emf=0.55 V at room temperature was indeed observed. The short circuit current is, as for the ceramic material, a strong function of wave length. These results are shown in FIG. 15. Temperature Dependence Ceramic photo-emf is a function of temperature. Results for barium titanate ceramic with 5 wt% CaTiO.sub.3 are shown in FIG. 16. For both Pb(Zr.sub.0.53, Ti.sub.0.47)O.sub.3 with 1 wt% Nb.sub.2 O.sub.5 added and barium titanate the photo-emf decreases with increasing temperature. In these measurements, the temperature ranged to the transition temperature, and photo-emf vanishing at the temperature at which the remanent polarization also vanishes. The remanent polarization vs. temperature for this material is also shown in FIG. 16. Similar results for single crystal barium titanate are shown in FIG. 17. The single crystal photo-emf are, of course, much smaller. Short circuit was measured as a function of temperature. Results for barium titanate +5wt% CaTiO.sub.3 are shown in FIG. 18. Similar results over the same temperature range were obtained for Pb(Zr.sub.0.53, Ti.sub.0.47)O.sub.3 +1 wt% Nb.sub.2 O.sub.5 material. In that case there was no maximum, the photocurrent still increasing with increasing temperature at 130.degree. C. Effects of Optical Properties In the arrangement shown in FIG. 1, the direction of polarization, and consequently the direction of the photo-emf is perpendicular to the direction of incidence of the light which is also the direction in which the light is strongly absorbed. The light only enters into a region near the surface of the material. The rapidity of the absorption depends strongly on the wave length of the light, the light becoming fully absorbed in a region closer and closer to the surface as one decreases the wave length of the light and approaches the band gap wave length. For shorter wave lengths, the light no longer enters the material and thus for these wave lengths the light induced effects decrease rapidly with decreasing wave length. Ceramic materials which exhibit these photo-emf's can appear transparent, translucent, and apparently opaque when viewed with white light. Light, however, obviously enters even the opaque materials to produce the photo-emf's. The apparent opacity is produced by diffuse reflection at granular boundaries. It is of course desirable to minimize the degree to which diffuse relectivity prevents light from entering the material. Nevertheless, the largest photocurrents and greatest photovoltaic efficiency has been originally observed in a material which appears opaque in thickness more than a few thousandths of an inch. The cross sectional drawing FIG. 19 depicts the way light enters the material with the arrangement as originally shown in FIG. 1. When a circuit connects the electrodes, the maximum density of current occurs near the surface, the current density decreasing in regions deeper within the thickness. Polishing the surfaces of these materials, however, increases the transparency and, as expected, the magnitude of the photocurrent and the photovoltaic conversion efficiency. An emf will also be produced by the arrangement shown in FIG. 20 provided, of course, that the electrodes are of a nature to allow light to enter the material. Normal thick metal electrodes are opaque to light. When metal electrodes are thin enough, they permit light to be transmitted and yet are sufficiently conductive to function as electrodes. Other conducting transparent electrodes include indium oxide. The emf now will be seen to appear across the thickness of the material, in the direction of the remanent polarization. In this arrangement the high dark resistance of any unilluminated bulk portion of the material is in series with the circuit connecting the electrodes. The current that can be drawn is limited. Maximum currents can be drawn when the thickness between the electrodes is equal to or less than the absorption depth of the radiation. Since, however, the saturation photo-emf is not a strong function of intensity, vanishing only for extremely low intensities, the full photo-emf per unit length v.sub.o can usually be observed for thin samples. Proposed Mechanism for the High Voltage Photovoltaic Effect in Ferroelectrics Briefly, it is proposed that the photo-emf results from the action of an internal field within the bluk of an individual ceramic grain on non-equilibrium carriers generated by illumination. These carriers move to screen the internal field. The photo-emf that appears is the open circuit result of such screening. A change in charge distribution upon illumination changes the voltage across a grain from an initial value of zero to the photovoltages which are observed. These photo-emf's appear across individual ceramic grains. What is observed as a length dependent high photovoltage is the series sum of the photo-emf's appearing across grains, each of which is characterized by saturation remanent polarization P.sub.o. The situation is shown schematically in FIG. 21. Individual grains typically are small, of the order of 10 microns in diameter. To produce a high photovoltage per unit length in the ceramic the voltage across an individual grain need not be large. For example the results in Table II for Pb(Zr.sub.0.65, Ti.sub.0.47)O.sub.3 with 7% La for Pb can be explained by individual grain photovoltage of only about 0.5 volts per grain. The clear implication of the experimental results (Table II and FIG. 5) is that for the range of grain sizes investigated, the photo-emf across a grain is more or less independent of the size of the grain. This is supported also by the singel crystal results. Ferroelectric crystals are characterized by large spontaneous polarization which would be expected to produce large emf's even in the dark. Such emf's are not observed even across highly insulating materials. This is presumed to be the result of space charge within the volume or on the surface of a ferroelectric crystal (which, in ceramics, are the individual grains or crystallites). The space charge produces a potential across a crystal cancelling the potential produced by the net polarization within they crystal. It is obvious that as long as there are sufficient charges within the crystal which are free to move, any potential produced by an internal polarization will eventually vanish. This dark zero potential state is the initial state of a crystal crystallite, grain, and of the ceramic body composed of these grains. The absence of a net potential in the dark does not however mean the absence of internal fields. Internal fields can be expected to exist and are the consequence of the spatial distribution of the charges which bring the net potentials across grains to zero. These spatial distributions can not be arbitrarily assigned, but are subjected to constraints of a basic physical nature. In the idealized two dimensional crystal shown in FIG. 22, the surface charge density .sigma.=P.sub.s reduces the potential between the surfaces to zero. If the surface charge density (in actuality this does not occur) is completely juxtaposed upon the bound polarization surface charge, which has a value P.sub.s, then there are no internal fields. Were there no space charge, the crystal would show an internal field P.sub.s /.epsilon..sub.b and a potential between the surfaces of P.sub.s l/.epsilon..sub.b. Such a field would be well above the dielectric breakdown strength of a real dielectric. For a single domain typical ferroelectric barium titanate P.sub.s =26.times.10.sup.-2 C/m, and the relative dielectric constant .epsilon..sub.r in the direction of polarization is 137. The field that would have to exist in the absence of compensation charge is over 2.times.10.sup.6 volts/cm which is well above the dielectric strengths typical of these materials. If such a field could momentarily exist within a ferroelectric crystal it would not exist for long but be reduced from its maximum value to some value below the dielectric strength of the material. The strong field would break down the material and a charge flow would produce a space charge distribution resulting in a new lower value for the internal fields within the crystal. Such a space charge distribution must exist in an actual crystal. The space charge serves to reduce the potential across a crystal to zero. Such charges have limited mobility and the materials continue to behave as insulators for ordinary strength applied fields. Such a space charge cannot occupy a delta function-like region as in the idealized situation shown in FIG. 22, but must occupy instead a finite volume. If these are localized near the surface of the crystal, then an internal field E.sub.b exists within the bulk of the material and additional fields E.sub.s exist within the space charge regions near the surface. It is hypothesized that these space charge regions are near the surface of real crystals with the charge distributed within a surface layer thickness s. The reasons for same are as follows: (1) The surface regions of ferroelectric crystals are characterized by regions whose dielectric, ferroelectric, and thermodynamic properties differ markedly from that of the bulk. These differences are best explained by the existence of strong fields in this region that would be produced by space charge. There is a considerable body of information in the literature supporting the existance and delineating the properties of these layers; (2) The interplay of space charge and the very non-linear dielectric constant of ferroelectric would be expected to localize space charge in a low dielectric constant layer near the surface. In ferroelectrics, unusually high, low field relative dielectric constants (of the order of 1000) can be expected to reduce in value with increasing field strength. Thus charge in a region reduces the dielectric constant of that region increasing the field strength of that region. This feedback mechanism can be shown to localize charge within a layer. The experimental results supporting the existance of surface layers will not be reviewed here, nor the calculations which support the localization of charge into layers as a result of a non-linear (saturable) dielectric constant. These may be reviewed by referring to the literature. A schematic description of a typical grain, i.e. crystallite, with space charge regions of thickness s, and a bulk region of thickness l, is shown in FIG. 23. The internal fields (in the two dimensional model) of such a charge distribution superimposed on that produced by the bound polarization charge will be calculated and also the effect of these fields on carriers within the bulk produced as the result of an internal photo effect (photoionization). Formulae for the photo emf that will be derived will have the correct sign, a linear dependence on remanent polarization, and the kind of temperature dependence that has actually been observed. In addition there will result an estimate of a size independent grain photo-emf for a typical ferroelectric, barium titanate, which is consistant with that implied from the observed ceramic emf, and single grain emf. The grain has as shown in FIG. 23: (1) A bulk region with dielectric constant .epsilon..sub.b and uniform polarization (at zero applied field) P.sub.o ; (2) Surface layers of dielectric constant .epsilon..sub.s, considerably less than that of the bulk. There are also polarization in the surface regions P.sub.s (x) which exist at zero applied field. These will generally be parallel to the bulk polarization at one end and anti-parallel at the other end; (3) Space charges in these surface layers which serves to remove any potential across the grain. It is the space charge layers which produce high fields which reduce the highly non-linear dielectric constant or the bulk to the lesser value in the surface layers, and also produce the remanent polarization, P.sub.s (x) with the surfaces. Such a structure also has an internal bulk field, and surface fields which can be calculated. For the purposes of this calculation we assume a simple two dimensional model shown in FIG. 24. The polarization with the various regions are assumed only for simplicity to be uniform within these regions. Again, only for simplicity those in the surface layers and the bulk are assumed equal in magnitude (i.e. P.sub.s (x)=P.sub.o). The space charge densities .+-.n.sub.o e are also assumed uniform and equal in magnitude. The polarizations are equivalent to four bound surface charge densities. EQU .sigma..sub.1 =P.sub.o .sigma..sub.2 =-2P.sub.o .sigma..sub.3 =0 .sigma..sub.4 =P.sub.o There are, using Gauss's law, electric fields as shown in FIG. 24. EQU E.sub.1 =(1/.epsilon..sub.S)[P.sub.o +M.sub.o EX] EQU e.sub.2 =(1/.epsilon..sub.b)[-P.sub.o +M.sub.o es] EQU E.sub.3 =(1/.epsilon..sub.s)[-P.sub.o +n.sub.o e(s-x)] It has been assumed that the voltage across the crystal vanishes, ##EQU1## n.sub.o and s, from this and the three preceeding equations, must be related by the expression ##EQU2## and the bulk field ##EQU3## Surface layers in barium titanate ceramic grains have been estimated at 10.sup.-6 cm (see for example Jona and Shirane, Ferroelectric Crystals, Pergammon Press, 1962). The remanent polarization typical of the ceramic material is about 8.times.10.sup.-2 C/m.sup.2, the relative dielectric constant of the poled ceramic about 1300. The high field dielectric constant will be estimated at roughly 0.5 the bulk dielectric constant. These numbers yield a bulk field, for a typical 10.sup.-3 cm grain of, EQU E.sub.2 =350 volts/cm The potential across the bulk would thus be approximately -0.35 volts. The remaining potential across the grain would be that across the surface layers. Illumination has the effect of producing charges which screen the internal field, E.sub.2, causing it to vanish. The negative voltage vanishes and a positive potential appears across the sample. The light makes the sample look more positive. This is exactly what happens as the result of a thermally-induced decrease in polarization. Thus the pyroelectric voltage is in the same direction as the photovoltage as is experimentally observed. In the fully screened case, the photo-emf is also the emf across the two surface layers ##EQU4## The light generated free electrons set up a counter field which tends to cancel the bulk field E.sub.2 ; thus, the observed voltage drop is less than it would be in a perfectly insulating medium. This is what is meant by the term screening. The counter field approaches -E.sub.2. Assuming the shielding occurs only in the bulk, the total voltage across the grain is now the sum of the voltages across the surface layers. The photo-emf is in the opposite direction to the bulk polarization. This fact predicted in the theory is what is always observed experimentally. The complete screening of the bulk field thus would, in barium titanate, be expected to result in a photo-emf of +0.35 volts per grain or 350 V/cm and about 0.35 volts across a macroscopic single crystal. These are roughly the values actually observed as seen in Table I, and with the single crystal results. The linear relation between remanent polarization and saturation photo-emf as shown in FIG. 6 is also predicted by these equations. The dependence on temperature of the photo-emf as shown in FIGS. 16 and 17 is predicated by the fact that as one approaches the curie temperature, not only is P.sub.o decreasing but the dielectric .epsilon..sub.s is increasing. The bulk internal field, E.sub.2, should therefore decrease with temperature more rapidly than the remanent polarization. Screening Solving the general problem of screening in a ferroelectric is difficult. Many of the principles involved can be demonstrated by solving a special case. The special case is meant to be particularly applicable to the Pb(Zr.sub.0.53, Ti.sub.0.47)O.sub.3 +1 wt% Nb.sub.2 O.sub.5 material. Utilized, only for simplicity, is a two dimensional model, with photo-produced carriers limited to those of a single sign. It will be assumed that these are electrons generated from deep trapping levels midway in the band gap, and that the illumination empties all the traps leaving fixed positive charges to replace the original traps. The complete emptying of a deep trapping level would produce the long wave length photovoltages and the phenomena of an intensity saturation of the photo-emf typical of the Pb(Zr.sub.0.53, Ti.sub.0.47)O.sub.3 +1 wt% Nb.sub.2 O.sub.5. Consider a two dimensional illuminated slab of length l within which is an internal field E and within which light generates a uniform density of electrons n.sub.o (n electrons per unit length). Schematically the situation is shown in FIG. 25, where .phi.(x) is the potential at a point x. The carriers respond to the internal field and occupy a Boltzman distribution EQU M=M.sub.o e .sup.e.phi./kt If the fields due to the electrons could be neglected, then EQU .phi.(e)=-Ex This is, of course, too rough an approximation. With n(0) the density of electrons at x=0, and n.sub.o, the density of the immobile donor ions EQU M(x)=M(0)e .sup.e.phi.(x)/kt with .phi.(x) given by Poisson's equation, ##EQU5## Since for .phi.=0 n(0)=n.sub.o, and since all traps are emptied, assuming electrical neutrality. ##STR2## If the crystal is neutral there must be no electric field at the boundary except the applied field -E.sub.o ##EQU6## These two boundary conditions allow the solution of Poisson's equation. ##EQU7## setting y(0)=0 since the zero for a potential may be set arbitrarily ##EQU8## integrating this equation from O to l yield ##EQU9## which is an implicit expression for .DELTA.V in terms of E.sub.o, l, and l.sub.D. For low n.sub.o and/or large E.sub.o, .GAMMA. is large ##EQU10## which is the original potential across the bulk of the crystal. The situation of interest is however large n.sub.o and small l.sub.D and small .GAMMA..sup.2. It is in this situation that ##EQU11## can be expected to vanish. Expanding the expression for .DELTA. small, which is always the case, then ##EQU12## Keeping only second order terms in y and .DELTA., then ##EQU13## This approximation for .DELTA.V is good for all reasonable values of T. Illumination thus reduces the dark bulk emf=E.sub.o l, producing a net photovoltage ##STR3## A simplified expression occurs for small l/(2l.sub.D) where, tan h.sub.x .congruent.x-1/3x.sup.3 ##EQU14## Here, it is clear that the photovoltage becomes insignificant for (l/l.sub.D) small. The implication is therefore that photovoltaic contributions from the bulk will be much larger than that from the surface layers, for surface layers are extremely small while l.sub.D can be estimated as very roughly equal in the bulk and the surface. Thus, illumination will result in the varnishing of the internal field within the bulk resulting in a max photo-emf. .DELTA.V=E.sub.2 l where E.sub.2 is the bulk field. For small intensities, we can assume n.sub.o small, then ##EQU15## i.e., the photovoltage is proportional to n.sub.o which can be reasonably assumed proportional to intensity which is experimentally observed (see FIG. 4). The model just described explains the long wave length photo-emfs, in the material Pb(Zr.sub.0.53, Ti.sub.0.47)O.sub.3 +1 wt% Nb.sub.2 O.sub.5. Such a deep trapping level is probably typical of the lead titanate-lead zirconate materials with characteristic lead vacancies. These bind electrons leaving holes (producing p type dark conductivity). The addition of common dopants--for example niobium gives rise to free electrons which combine with holes or get trapped by the lead vacancies. The doping can thus be said to provide electrons which fill traps. It is these trapped electrons which are photo-injected into the conduction band by the long wave length light providing near maximum photo-emfs in material illuminated at 500 nm and even longer wave lengths as shown in the results plotted in FIG. 13. Full saturation, that is the complete shielding of the bulk internal field, requires however band gap carriers which occurs as one approaches the 373 nm band gap wave length. Solving this problem, that of band gap carriers in addition to electrons generated by deep traps, can be accomplished in a manner similar to that which was accomplished for the trapped electrons but is more complex for example because mobile holes are being produced in addition to electrons and one cannot necessarily fix the maximum number of carriers. The photo-emfs are created by photo-induced carriers shielding the bulk field. Effectively, no photocurrent can flow however unless band gap light is present as is clear from the results shown in FIGS. 12 and 13. Here it is clear that the band gap light produces maximum photo-emf and maximum photocurrents, less than band gap light, max or almost maximum photo-emf but no photocurrents and that the output resistance under these circumstances appears extremely high. Addition of band gap light allows current to flow. The tentative explanation is that the surface layers form high resistance barriers, the magnitude of which lowers with band gap light. The surface layers thus act as intrinsic photoconductors in series with an emf. This picture not only explains the rather unique dependence of photo-emf and short circuit photo-current on wave length as shown in FIGS. 12 and 13 but also the equivalent circuit which is typical of all these materials as described in FIG. 2 and as indicated by the current-voltage results in FIG. 3. A possible explanation for the high resistance of the surface layers is that they include quantities of charged ions which have been localized there. These are immobile under normal applied voltages moving only under the action of high fields such as produced by the reversal of the remanent polarization. Those ions not only will occupy trapping levels, eliminating the need for easily ionized trapped electrons and thus reducing the intrinsic conductivity but also form centers for coulomb scattering of conduction electrons which should contribute markedly to the resistivity. Efficiency Some insight into the possible maximum efficiency of the process can be obtained by considering carriers generated by band gap light with potential energy ##EQU16## with .phi.(x)<Ex so that a maximum value of energy ##EQU17## The energy required to produce .delta.m.sub.o electron hole pairs EQU .epsilon.=.delta.M.sub.o LEg, where Eg is the band gap energy. The power into the crystal is ##EQU18## while the power out (time rate of increase in internal potential energy) is ##EQU19## For Pb(Zr.sub.0.53, Ti.sub.0.47)O.sub.3 +1 wt% Nb.sub.2 O.sub.5 added E is roughly 600 v/cm and the grain size roughly 5 microns. The emf across a grain is thus about 0.3 volts. The band gap is about 3 eV. Thus the efficiency is EQU .congruent.0.3/3 .congruent.10%, which compares with an observed band gap efficiency of about 0.06%. The calculation, of course, depends on idealizing assumptions, some of which may be practically obtainable. Radioactively Ionized Battery The teaching herin may be applied toward the provision of a novel high voltage battery of the present invention which serves to convert radiation such as X-radiation in this instance, directly into electrical energy. In this respect, a block or substrate of ferroelectric ceramic material would again be provided to which electrodes are attached in the identical fashion as was discussed with respect to the basic physical configuration disclosed above and illustrated in FIG. 1 of the application drawings. An example of the constituent material of the ferroelectric ceramic in this instance is solid solution PZT-5A consisting of 53 mole percent ZrTiO.sub.3 and 47 mole percent PbTiO.sub.3 with 1 percent by weight niobium added, such as Nb.sub.2 O.sub.5. This ferroelectric ceramic material would be poled in the usual fashion by the application of a high voltage applied across the electrodes. To function as a battery, the ceramic material can contain a radioactive component and this can be all or a portion of any of the above-discussed constituent elements. For example, the material may be fabricated with a radioactive isotope of Zr,TiO,Nb, etc., or a radioactive additive can be added to the composition. Alternatively, the composition may be placed next to a strong radioactive source and, for example, could actually be coated with a radioactive material. The primary requirement herein is that a flux of gamma rays or X-rays within the material be produced, which radiation has the effect of ionizing the ferroelectric ceramic material so as to produce non-equilibrium carriers. Thus, in the instance of the application of a poled ferro-electric ceramic material as a high voltage battery, an external light source would not be required as the ionizing source in that the non-equilibrium carriers would be produced by the internal ionization of the ferroelectric ceramic material effected by the radiation and would result in an emf which would appear across the electrodes. Accordingly, an open circuit voltage proportional to the length of the ferroelectric ceramic material between the electrodes and inversely proportional to average grain size, and the like as was discussed at the outset of this specification would be produced by the gamma or X-radiation. Similarly, a short circuit current proportional to the electrode area and the net (steady state) increment of excess carriers introduced into the conduction band would likewise be produced, this being related to the intensity of the ionizing radiation. As can be appreciated, the emf would persist as long as the ionizing radiation persisted and, extrapolating from the detailed photo-effect results, the emf produced by this high voltage battery would be relatively independent of the intensity of the radiation and thus not strongly dependent on the half-life of the radioactive material. While there has been shown and described several preferred embodiments and applications of the basic invention hereof, those skilled in the art should appreciate that such embodiments are exemplary and not limiting and are to be construed within the scope of the following claims: ACCORDINGLY
	description	The present application claims priority from Japanese application JP 2007-168095 filed on Jun. 26, 2007, the content of which is hereby incorporated by reference into this application. 1. Field of the Invention The present invention relates to an X-ray imaging system and method for nondestructive testing of the inside of an object. 2. Description of the Related Art Imaging systems for nondestructive observation of the inside of a sample using X-rays include an absorption-contrast X-ray imaging system using a change in X-ray intensity caused by the sample as image contrast, and a phase-contrast X-ray imaging system using a change in phase as the contrast. The former, namely, the absorption-contrast X-ray imaging system, is mainly composed of an X-ray source, a sample setting mechanism and a detector. The X-rays emitted from the X-ray source are irradiated on the sample positioned by the sample placement mechanism, and the X-rays that have passed through the sample are detected by the detector. Thereby, an image using the change in the intensity of X-rays caused by the sample absorption as the contrast is obtained. Because of a simple principle of measurement and a simple system configuration, this system is widely used in many fields including medical diagnosis, in the name of roentgen for two-dimensional observation and X-ray computed tomography (CT) for three-dimensional observation. On the other hand, the latter, namely, the phase-contrast X-ray imaging system, requires a means for detecting a phase-shift to the above-mentioned system configuration in addition; however, this system is capable of observing biological soft tissues, with extremely high sensitivity, without contrast agents and with low X-ray damage, as compared to the absorption-contrast X-ray imaging system. This is due to the fact that a scattering cross-section that effects the phase-shift is, in terms of light elements, about 1000 times larger than a scattering cross-section that effects the change in the intensity. The phase-shift detecting means include (1) a method using an X-ray interferometer (i.e., an X-ray interference method), as disclosed in Japanese Unexamined Patent Application Publication No. Hei 4-348262; (2) a method utilizing a refraction angle θ of the X-rays which is proportional to spatial differential of the phase-shift (i.e., a refraction-contrast method, diffraction enhanced imaging (DEI)), as disclosed in Japanese Patent Application Publication No. Hei 9-187455; and (3) a method using X-ray Fresnel diffraction. The difference in principle among the above-mentioned methods is that the method (1), namely, the X-ray interference method, is detecting the phase-shift directly, whereas the other methods are detecting the spatial differential of the phase-shift. Description will be outlined below with regard to the methods (1) and (2) concerned deeply with the present invention. The system for the above-mentioned method (1), namely, the X-ray interference method, is composed of the X-ray interferometer, such as a Bonse-Hart interferometer (such as described in Appl. Phys. Lett. 6, 155 (1965)) or an interferometer by dividing the crystal of this type of interferometer into multiple crystal blocks (such as described in J. Appl. Cryst. 7, 593 (1974)), in addition to the X-ray source, the sample placement mechanism and the detector. FIG. 1 is a perspective view schematically showing the configuration of the Bonse-Hart interferometer. The Bonse-Hart interferometer includes three wafers (a beam splitter 1, a mirror 2, and an analyzer 3) disposed parallel to one another at regular intervals, and is made of a crystal block formed monolithically of a single crystal ingot. An incident X-ray 4 is split by the first wafer (the beam splitter 1) into two beams 5 and 6, which are thereafter reflected by the second wafer (the mirror 2) and then combined at the third wafer (the analyzer 3) to form two interference beams 7 and 8. When a sample 9 is installed on an optical path of any one of the split beams 5 and 6, a phase-shift p of the beams caused by the sample 9 changes the intensity of the interference beams 7 and 8 by superposition (or interference) of waves. Utilizing this principle, an image (or a phase-map) indicating spatial distribution of the phase-shift p caused by the sample is obtained, by using a method called “sub-fringe”, from an intensity distribution image of the interference beams 7 and 8 detected by an image detector or the like. In this instance, using, as the sub-fringe method, a Fourier transform method disclosed in Appl. Opt. 13 (1974) 2693 enables to obtain the phase-map from a single interference image and thus to observe even a phenomenon that changes rapidly with time. Also, imaging systems capable of three-dimensional nondestructive observation using a combination of the phase-contrast imaging method and a typical X-ray CT approach include the system disclosed in Japanese Unexamined Patent Application Publication No. Hei 4-348262. As in the case of the typical X-ray CT, this system involves irradiating a sample with X-rays in multiple different directions, and reconstructs a cross-section image of the sample by computation based on a phase-map acquired for each projection. The above DEI method (2) obtains the phase shift p, utilizing a phenomenon in which the direction of propagation (or a wavefront) of the X-ray is slightly diverged by refraction as shown in FIG. 2 if the phase shift p is spatially nonuniform when the X-ray passes through a sample that causes the phase shift p. The refraction angle θ of the X-ray caused by the sample is given by Equation (1) as a function of the spatial differential of p: θ = λ 2 ⁢ ⁢ π ⁢ ⅆ p ⅆ x ( 1 ) where λ denotes the wavelength of the X-ray. Thus, detection of θ enables to obtain the spatial differential of the phase shift p, and further, the spatial integration enables to obtain the phase shift p. In a hard X-ray region, the refraction angle θ is generally a very small value of approximately a few μrad. Thus, X-ray diffraction of a flat plate single crystal 10 called an analyzer crystal is utilized for detection of θ (see FIG. 2). When an incident angle θB of the X-ray with respect to the analyzer crystal satisfies diffraction conditions expressed as the following Equation (2):λ=2d sin θB (2)within a range of angles of a few grad, the incident X-ray is diffracted (or reflected) by the analyzer crystal. Here, d denotes a lattice spacing of diffraction plane. Accordingly, when the direction of propagation of the X-ray is not diverged (θ=0), the incident angle of the X-ray with respect to the analyzer crystal is set so as to satisfy Equation (2), and thereby, intensity I of the diffracted X-ray depends on θ and gets the maximum when θ=0, and decreases with increasing of θ and gets almost zero when θ equals a few μrad. Utilizing this phenomenon, θ, that is, an image, the contrast of which is represented by the amount of spatial differential of the phase-shift, can be obtained from the spatial distribution (or the diffraction image) of the diffraction intensity I, and further, an image (or the phase map) showing the spatial distribution of the phase shift p can be obtained by integration calculation. Incidentally, besides X-ray diffraction based on Bragg-case, a method utilizing X-ray diffraction based on X-ray transmission Laue-case is also developed (see Jpn. J. Appl. Phys. 40 (2001) L844), and recently, a method utilizing a transmitted wave is called a dark field, and a method utilizing a diffracted wave is called a bright field. As can be seen from FIG. 2, the use of a single diffracted image (or reflected image) alone cannot distinguish between the change in intensity caused by the absorption of the X-ray by the sample and the change in intensity caused by θ, and hence cannot quantitatively determine θ. Thus, generally, the DEI method involves rotating the analyzer crystal in the vicinity of a Bragg angle, and calculating θ from multiple obtained diffracted images. In this instance, rotation methods include (a) a “two-point method” using two angles alone for measurement (see Phys. Med. Biol. 42 (1997) 2015), and (b) a “scan method” using three or more angles for measurement (see Japanese Patent Application Publication No. Hei 9-187455). The “two-point method” (a) uses two angles which sandwich a Bragg angle θB to obtain an image. If the incident angle of the X-ray on the analyzer crystal is set to an angle at which the diffraction intensity value is half of the peak value (θB±dθD/2), intensity Ir of the X-ray diffracted by the crystal is given by Equation (3): I r = I o ⁢ R ⁡ ( θ B ± d ⁢ ⁢ θ D 2 + θ ) ( 3 ) where Io denotes intensity of the incident X-ray, and R denotes reflectance of the analyzer crystal. At the above angle, R is substantially proportional to θ, so that R can be approximated by a second-order Taylor expansion as given by Equation (4). R ⁡ ( θ B ± d ⁢ ⁢ θ D 2 + θ ) = R ⁡ ( θ B ± d ⁢ ⁢ θ D 2 + θ ) + ⅆ R ⅆ θ ⁢ θ ( 4 ) The diffraction intensity (I1 and Ih) at a low angle (θL=θB−dθD/2) and a high angle (θH=θB+dθD/2) are expressed as Equations (5) and (6), respectively, from Equations (3) and (4). I l = I o ⁡ ( R ⁡ ( θ L ) + ⅆ R ⅆ θ ⁢ θ ) ( 5 ) I h = I o ⁡ ( R ⁡ ( θ H ) + ⅆ R ⅆ θ ⁢ θ ) ( 6 ) Erasing I0 from the above equations leads finally to θ being expressed as Equation (7). θ = I l ⁢ R ⁡ ( θ L ) - I h ⁢ R ⁡ ( θ H ) I l ⁢ ⅆ R ⅆ θ ⁢ ( θ H ) - I h ⁢ ⅆ R ⅆ θ ⁢ ( θ L ) ( 7 ) Accordingly, the refraction angle θ (x, y) at each point (or pixel) on the sample can be obtained by performing calculation of Equation (7) for each point of I1 and Ih obtained at the above two angles. Also, the phase-map can be obtained by integrating θ (x, y) at each obtained point in a direction horizontal to the sheet of FIG. 3. Note that, if there is a great change in density of the sample and thus a change in θ is greater than an angular width of diffraction (up to dθD), the diffraction intensity becomes zero or a value different from the intended value over the diffraction peak, and cannot be detected normally. Thus, the largest dp/dx value detectable with this method is limited by Equation (8). ⅆ p ⅆ x = d ⁢ ⁢ θ D 2 ⁢ 2 ⁢ π λ ( 8 ) The “scan method” (b) involves, as shown in FIG. 4, rotating the analyzer crystal at an angle of the angular width of diffraction (up to dθD) or greater in the vicinity of the Bragg angle, and calculating the refraction angle θ from multiple obtained diffracted images (typically, three or more images). This method is characterized in that rotation of the analyzer crystal at a large angle enables detection of θ greater than dθD/2, and there is no limitation on a density dynamic range, which is a problem of the method (a). In this method, the diffraction intensity changes as shown in FIG. 5 with the rotation θA of the analyzer crystal, and thus, the intensity of the diffracted beam of the X-ray that passed through each point (x, y) on the sample has a peak at an angle offset by the refraction angle θ from the Bragg angle θB. Thus, the refraction angle θ can be calculated from Equation (9) as the center of the intensity of the diffracted beam: θ ⁡ ( x , y ) = ∑ n ⁢ ⁢ θ n ⁢ I n ⁡ ( θ n , x , y ) ∑ n ⁢ ⁢ I n ⁡ ( θ n , x , y ) ( 9 ) where θn denotes each angle of the analyzer crystal, and In(θn) denotes the intensity of the diffracted beam obtained at θn. Thus, the spatial distribution image (or the phase-map) of the phase shift p can be obtained by integrating θ (x, y) at each obtained point in a direction horizontal to the sheet of FIG. 4, as in the case of the two-point method. Also, the DEI method can involve rotating the sample with respect to the incident X-ray and nondestructively obtaining the cross-section image of the sample by calculation of reconstruction from the projection image obtained at each angle, as in the existing X-ray CT. The X-ray interference method (1) detects a phase shift α caused by the sample as a wrapped value α′ (α′=α−Int(α/2π)*2π) wrapped within 0 to 2π, as shown in FIG. 6. Thus, it is required that a method disclosed in Japanese Patent Application Publication No. 2001-153797, or the like be used to perform complicated operation called phase unwrapping and restore the true amount of phase shift α (see FIG. 6). Also, in a region where the shape or inside structure of the sample is complicated and thus the density spatially sharply changes, the refraction angle θ is so large that the X-ray greatly deviates from the original optical path, and that deterioration in visibility of the interference image, disappearance of interference fringes, and the like occur. As a result, a problem arises that the above unwrapping process is not performed normally, and thus, a cannot be restored accurately. To avoid this problem, there is a method that involves soaking a sample in a liquid and reducing a difference in density between the sample and its periphery, as disclosed in Japanese Unexamined Patent Application Publication No. Hei 7-209212; however, this method cannot treat a sharp change in density in the inside, although being able to reduce the influence on the shape. The both DEI method (2) (the two-point method and the scan method) involves rotating the analyzer crystal in the vicinity of the Bragg angle and thereby obtaining the image. This method is based on a condition that the state of the sample is steady during measurement, and if a change in the state occurs during the measurement, an accurate image cannot be obtained. Thus, this method has the problem of requiring a long measurement time and thus being unable to perform time-resolved observation. Also, if the intensity of the incident X-ray varies with time, the intensity of the image obtained at each angle also varies, and thus, the refraction angle θ cannot be determined accurately, so that the density resolution deteriorates. Further, measurement of a sectional image using the CT requires repeating angular scan several hundred times. However, it is difficult to accurately ensure the angular reproducibility of the analyzer crystal under the influence of drift rotation caused by a temperature and the like. Summarizing the above, the X-ray interference method can obtain the phase-map from one image by using Fourier transform method and thus takes a short measurement time; however, this method has the problem of narrow density dynamic range. Meanwhile, the DEI method has a wide dynamic range; however, this method has the problem of having to obtain at least two images and thus taking a long measurement time. Against such a background, an object of the present invention is to solve the above problems, and to provide an X-ray imaging system and method capable of performing time-resolved observation in the same density resolution and dynamic range as the DEI method in a short measurement time and also observing the sample with high sensitivity even if the intensity of the incident X-ray varies with time. The present invention utilizes multiple X-ray diffractions as described in detail below to thereby solve the above problems. The X-ray diffraction is a phenomenon in which the X-ray is diffracted by a crystal lattice plane, and is classified into the Laue-case in which the incident X-ray and the diffracted X-ray lie on different sides of crystal planes (see FIG. 7A) and the Bragg-case in which the incident X-ray and the diffracted X-ray lie on the same side of crystal plane (see FIG. 7B). In the Laue-case and the Bragg-case in which the crystal is extremely thin, the incident X-ray is split into two beams, namely, the transmitted X-ray and the diffracted X-ray. In the X-ray diffraction in the Laue-case, the intensity Ig of the diffracted X-ray is given by Equation (10) based on dynamical theory of X-ray diffraction, and the intensity Ih of the transmitted X-ray is given by Equation (11). I g I o = 1 2 ⁢ ( W 2 + 1 ) ( 10 ) I h I o = 1 - 1 2 ⁢ ( W 2 + 1 ) ( 11 ) Here, the absorption of the X-ray by the crystal is ignored. Also, Io denotes the intensity of the incident X-ray, and W denotes a variable given by the following Equation (12): W = d ⁢ ⁢ θ ⁢ ⁢ sin ⁢ ⁢ 2 ⁢ ⁢ θ B  χ g  ( 12 ) where dθ denotes a deviation from the Bragg angle, and xg denotes electric susceptibility, and thus, Ig and Ih depend on dθ, i.e., the deviation of the incident angle from the Bragg angle. FIG. 8 shows the calculated Ig and Ih of a lattice plane (220) of a silicon crystal, based on Equations (10) and (11). The horizontal axis indicates the deviation of the incident angle from the Bragg angle, and the vertical axis indicates the intensity of the X-ray. Energy of the X-ray was set to 35 keV, and the thickness of the crystal was set to 1 mm. From this drawing, it can be seen that the X-ray is diffracted only when the incident angle of the X-ray is in the vicinity of the Bragg angle, and other X-rays are transmitted. On the other hand, in the X-ray diffraction in the Bragg-case, the intensity Ig′ of the diffracted X-ray and the intensity Ih′ of the transmitted. X-ray are given by Equations (13) and (14) based on dynamical theory of X-ray diffraction, as in the case of the Laue-case. I g I o = { (  W  - W 2 - 1 ) 2 ⁢ : ⁢ ⁢  W  ≥ 1 1 ⁢ : ⁢ ⁢  W  ≤ 1 ( 13 ) I h I o = { 1 - (  W  - W 2 - 1 ) 2 ⁢ : ⁢ ⁢  W  ≥ 1 0 ⁢ : ⁢ ⁢  W  ≤ 1 ( 14 ) Here, W is given by Equation (12), and both Ig′ and Ih′ depend on the incident angle. FIG. 9 shows the calculated results of Ig′ and Ih′ at the lattice plane (220) of the silicon crystal, based on Equations (13) and (14). The horizontal axis indicates the deviation of the incident angle from the Bragg angle, and the vertical axis indicates the intensity of the X-ray. Energy of the X-ray was set to 35 keV, and the thickness of the crystal was set to 1 mm. From this figure, it can be seen that the X-ray is diffracted only when the incident angle of the X-ray is in the vicinity of the Bragg angle, and other X-rays are transmitted, as in the case of the Laue-case. Discussion will now be made with regard to Laue-case X-ray diffraction using a series arrangement of two crystal wafers one of which relative angle is deviated by Δω as shown in FIG. 10. In this instance, the intensity I1 of the X-ray diffracted by a first crystal wafer 11 is given by Equation (10). Moreover, the intensity I2 of the X-ray diffracted by a second crystal wafer 12 is given by Equation (15), because it is the product of Equations (10) and (11). Further, the intensity It of the X-ray that has passed through the second crystal wafer is given by Equation (16) from Equation (11). I 2 I o = 1 2 ⁢ ( ( W + Δω ) 2 + 1 ) - 1 4 ⁢ ( ( W + Δω ) 2 + 1 ) ⁢ ( W 2 + 1 ) ( 15 ) I t I o = ( 1 - 1 2 ⁢ ( W 2 + 1 ) ) ⁢ ( 1 - 1 2 ⁢ ( ( W + Δω ) 2 + 1 ) ) ( 16 ) FIG. 11 shows the calculated results of I1, I2 and It under the same calculation conditions as those shown in FIG. 8 and under the condition that Δω=10 μrad. From these results, it can be seen that I1 is intense in an angular range around θB; I2, in an angular range around θB+Δω; and It, in an angular range excluding θB and θB+Δω. As apparent from the arrangement shown in FIG. 10, I1, I2 and It can be detected at a time. Consequently, two images, which have been heretofore obtained in sequence by scanning the angle of the analyzer crystal at the angles θB and θB+Δω, can be obtained at a time. Accordingly, when Δω is set to dθD and the angle of the first crystal is set to θB−dθD/2, the above-mentioned two-point method can be used to obtain the images Ih and I1 at a time, and this eliminates the need for the rotational scan of the analyzer crystal. Also, for the scan method, setting of Δω to around dθD/5 enables obtaining the images of the low and high angles of the diffraction peak at a time, and thus enables reducing the number of scans by half or more. Incidentally, it is also applicability for the Bragg case in which the thickness of the crystal is extremely thin. Although description has been given above with regard to an instance where two crystal wafers are used, n crystal wafers may naturally be used (where n denotes an integer equal to or more than three). In this instance, the deviation of the angle between crystals by dθD/(n−1) makes it possible to obtain n diffracted images at θn in Equation (9) at a time. Accordingly, this eliminates the need for scanning the analyzer crystal from the scan method. As can be seen from the above, the utilization of multiple X-ray diffractions eliminates the need for scanning the analyzer crystal, and thus enables time-resolved observation over a wide density dynamic range and also enables high-sensitivity observation of the sample even if the intensity of the incident X-ray varies with time. The present invention enables time-resolved observation over a wide density dynamic range and also enables high-sensitivity observation of an image using the spatial phase-shift of the sample as the contrast even if the intensity of the incident X-ray varies with time. Description will be given below with reference to the drawings with regard to embodiments of the present invention. In the drawings, parts having the same function are indicated by the same reference numerals, and repeated description thereof will be omitted. FIG. 12 is a view showing the configuration of an example of an X-ray imaging system according to the present invention. The X-ray imaging system is composed of a single crystal block 13 formed monolithically having two crystal wafers 11 and 12, a rotational mechanism 14, a crystal block positioning mechanism 15, a sample holder 16, a sample holder positioning mechanism 17, an X-ray imager 18, a controller 19, a processing unit 20, and a display device 21. X-rays 22 that have passed through a sample enter the first crystal wafer 11 of the single crystal block, only the X-rays that satisfy a given angle condition are diffracted to form diffracted X-rays 23, and the other X-rays pass through the first crystal wafer to form transmitted X-rays 24. The transmitted X-rays 24 further enter the second crystal wafer 12, only the X-rays that satisfy a given angle condition are diffracted to form diffracted X-rays 25, and the other X-rays pass through the second crystal wafer to form transmitted X-rays 26. The diffracted X-rays are detected by the X-ray imagers 18, respectively. Incidentally, the use of a two-dimensional X-ray imager as the X-ray imager 18 enables detection of a two-dimensional image of the sample without the need for spatial scan of X-ray beams. Further, when the crystal wafers 11 and 12 are disposed at narrow spaced intervals, so that the diffracted X-rays are arranged substantially side by side as shown in FIG. 12, an X-ray imager with a large field of view can be used alone to detect both X-rays at a time. With such a configuration, a control system can be further simplified. When the sample is placed in an optical path of the incident X-ray beam by use of the sample holder 16 positioned by the sample holder positioning mechanism 17, the direction of propagation of the X-ray beams 22 that have passed through the sample is deviated by a refraction angle θ by the refraction effect of the sample. As a result, the incident angle to the crystal wafers 11 and 12 changes, and thus, the diffracted X-rays 23 and 25 also change in intensity according to the change in the angle. For this reason, the refraction angle caused by the sample can be detected from the change in the intensity of the diffracted X-rays. When the angle of the crystal wafer 11 is preset to an angle that reduces the diffraction intensity by half (or the lower angle than the Bragg angle) as shown in FIG. 3, the intensity Ir1 of the diffracted X-ray given by Equation (5) can be obtained. Incidentally, at this time, the diffraction intensity is most sensitive to the refraction angle. Also, when the angle of the crystal wafer 12 is preset to another angle that reduces the diffraction intensity by half (or the higher angle than the Bragg angle) by use of the rotational mechanism 14, the intensity Ir2 of the diffracted X-ray given by Equation (6) can also be obtained. Thereby, the refraction angle of the X-ray caused by the sample can be obtained from the detected Ir1 and Ir2, by means of the two-point method, using Equation (7). Further, integration enables to obtain the phase-map of the sample. Further, in addition to the above-mentioned measurement, when the crystal block positioning mechanism 15 is used to obtain multiple images while rotationally scanning the single crystal block 13, an angular difference between the crystal wafers 11 and 12 can be set to an angular width of diffraction by the rotational mechanism 14 so that the diffracted X-rays at the lower angle than the Bragg angle and the diffracted X-rays at the higher angle than the Bragg angle can be detected at a time by the crystal wafers 11 and 12, respectively. Accordingly, in the scan method, the number of angular scans that have been heretofore required n times can be reduced by half, i.e. to n/2 times, and this enables a reduction in measurement time and a reduction in X-ray damage. Incidentally, the refraction angle caused by the sample can be obtained from multiple diffracted X-ray images acquired through angular scan as mentioned above, in the same manner as hitherto, by Equation (9). The diffraction plane of the crystal wafer is determined based on the energy of X-rays to be used, the size of the sample, a required density resolution, and a required dynamic range. If a large observation field is required, a low-order lattice plane having a large Bragg angle can be selected. If the sufficient density resolution is required, a high-order lattice plane having the intensity curve shown in FIG. 3 with a sharp gradient can be selected. If a wide dynamic range is required, a low-order lattice plane having a wide diffraction width can be selected. If crystal strain or the like remains in the crystal wafers 11 and 12 that form an angular analyzer, the diffraction condition becomes spatially nonuniform, and thus, accurate observation of the sample image becomes impossible. Thus, the crystal wafer can be subjected to mechanochemical polishing or the like on the surface thereof to form the crystal wafer with little strain and high flatness for use. However, even after the above process is finished, the strain cannot be completely removed. Thus, a procedure shown in FIG. 13 is used to remove a nonuniform distribution (or a background refraction angle) of the diffraction condition (or the Bragg angle) that forms a background and thereby detect the refraction angle formed only by the sample. (1) Prior to placement of the sample, the background refraction angle is obtained by the same method as the present measurement (the measurement of the background distribution). (2) The sample is placed in an optical path by use of the sample holder 16 and the sample holder positioning mechanism 17. (3) The distribution of the sum of the refraction angle of the background and that of the sample is obtained. (4) The distribution image of the refraction angle caused by the sample is obtained from the distribution image of the refraction angle obtained in step (1) and (3) by subjecting the background refraction angle to a subtraction process. Further, an integration calculation is performed to obtain the phase-map of the sample (or the spatial distribution image of the phase of the sample). Angle control of the crystal wafer is extremely important since the angular difference of the extremely slight refraction angle is detected. If the crystal wafer drifts rotationally during measurement, the refraction angle cannot be obtained accurately. Thus, the first embodiment uses a precise positioning table using a tangential bar system as the crystal block positioning mechanism 15. Employing this mechanical mechanism enables achieving a rotational positioning accuracy of 1/100 arc second or less and a drift of 1/10 arc second or less. It is also required that the angular difference between the crystal wafers 11 and 12 be controlled with an extremely high accuracy of approximately a few seconds. An example of the rotational mechanism 14 for this purpose is shown in FIGS. 14A and 14B. FIG. 14A is a front view of the single crystal block, and FIG. 14B is a plan view thereof. Here, a notch 57 is cut in the single crystal block 13 that support the two crystal wafers 11 and 12, and the interval of the notch is opened or closed by a piezo 58 to thereby adjust the angular difference. The notch 57 extends from the lateral side of the single crystal block between the two crystal wafers 11 and 12, and the piezo 58 is interposed at an open end of the notch. When the depth of the notch is set to 50 mm and the accuracy of expansion and contraction of the piezo is set to 10 nm, an angular difference of 0.04 arc second can be controlled. Incidentally, in order to reduce the rotational drift of the angular difference over a long time by relaxation of stress of the piezo 58 or the like, a measuring mechanism 56 using a capacitance sensor or a laser may be built in as shown in FIG. 14A, and active control for controlling a voltage applied to the piezo 58 so as to offset the drift may be used. As the X-ray imager 18, an X-ray film may be used, or a combination of a scintillator, a focusing optical system (e.g., a lens or an optical fiber) and a CCD camera or the like may be used. The latter enables high-accuracy measurement with high efficiency of X-ray detection, in real time, in a short measurement time. Also, multiple X-ray imagers may be prepared to measure transmitted X-rays besides diffracted X-rays and thereby detect all other undiffracted X-rays. The use of the transmitted X-rays for calculation enables detection with higher accuracy. As described above, the present invention enables detection of the spatial distribution image of the refraction angle caused by the sample and phase-map, without performing the angle scan of the analyzer crystal (i.e., the crystal wafers 11 and 12) if the two-point method is used, or by doing scans, the number of which is half of the number of scans that has been heretofore done, if the scan method is used. This enables observation of the transmitted image of the sample with high sensitivity, in a short measurement time, with low X-ray damage, without consideration of fluctuations in the incident X-ray intensity. In the first embodiment, the Laue-case X-ray diffraction is used to split X-rays. The X-ray in the crystal wafer of the Laue-case X-ray diffraction is spread by the influence of a phenomenon called “Borrmann fan.” Thus, the X-ray beam is blurred, resulting in deterioration in the spatial resolution. Here given is an embodiment in which the Bragg-case X-ray diffraction is employed to reduce the deterioration in the spatial resolution due to the above-mentioned phenomenon. FIG. 15 shows details of crystal wafers 27 and 28 and a single crystal block 29 for use in the second embodiment. Incidentally, the configuration other than the crystal wafers 27 and 28 and the single crystal block 29 is the same as that of the first embodiment. X-rays 30 that have passed through the sample enter the crystal wafer 27, and by the Bragg-case X-ray diffraction, the X-rays that satisfy a given angular range are reflected by diffraction to form diffracted X-rays 31, and the other X-rays pass through the crystal wafer to form transmitted X-rays 32. Further, the transmitted X-rays 32 enter the second crystal wafer 28, and by the Bragg-case X-ray diffraction, only the X-rays that satisfy a given angle condition are diffracted to form diffracted X-rays 33, and the other X-rays pass through the crystal wafer to form transmitted X-rays 34. The diffracted X-rays are detected by the X-ray imagers. As in the case of the first embodiment, when the angle of the crystal wafer 27 is preset to an angle that reduces the diffraction intensity by half (or the lower angle than the Bragg angle), the intensity In of the diffracted X-rays given by Equation (5) is obtained. Also, when the angle of the crystal wafer 28 is preset to another angle that reduces the diffraction intensity by half (or the higher angle than the Bragg angle) by use of a rotational mechanism 35, the intensity Ir2 of the diffracted X-rays given by Equation (6) may also be obtained. Thereby, the refraction angle of the X-ray caused by the sample can be detected from the detected Ir1 and Ir2, by means of the two-point method, using Equation (7). Further, integration enables to obtain the phase-map of the sample. In addition to the above-mentioned measurement, to obtain multiple images while rotationally scanning the single crystal block, an angular difference between the crystal wafers 27 and 28 can be set to an angular width of diffraction by the rotational mechanism 35 so that the diffracted X-rays at the lower angle than the Bragg angle and the diffracted X-rays at the higher angle than the Bragg angle can be detected at a time by the crystal wafers 27 and 28, respectively. Thus, in the scan method, the number of angular scans that have been heretofore required n times can be reduced by half, i.e. to n/2 times, and this enables a reduction in measurement time and a reduction in X-ray damage. Incidentally, the refraction angle caused by the sample can be obtained from multiple diffracted X-ray images θn obtained through angular scan as mentioned above, in the same manner as hitherto, by Equation (9). A method for selection of the diffraction plane, a method for removing the nonuniform distribution (or the background refraction angle) of the diffraction condition (or the Bragg angle) that is the background, and the positioning table, which are the same as those of the first embodiment, can be used. As described above, the second embodiment can utilize the Bragg-case X-ray diffraction to detect the spatial distribution image of the refraction angle caused by the sample and phase-map, without performing the angular scan of the analyzer crystal (i.e., the crystal wafers 27 and 28) if the two-point method is used, or by doing scans, the number of which is half of the number of scans that has been heretofore done, if the scan method is used. This enables observation of the transmitted image of the sample with high spatial resolution and with high sensitivity, in a short measurement time, with low X-ray damage, and without consideration of fluctuations in the incident X-ray intensity. Since the first and second embodiments use two crystal wafers, the “scan method” requires the rotational scan of the single crystal block mounting the crystal wafers. The scan angle width of the rotational scan is a few seconds and the angular step width is of approximately 1/10 arc second, and thus, the rotational mechanism for the crystal block requires high positioning and repeating accuracy. In addition, there is another problem that a long measurement time is required and thus the application to time-resolved observation is difficult. Here given is an embodiment in which a single crystal block 36 mounting n crystal wafers is employed to eliminate the need for the rotational scan of the single crystal block, as shown in FIG. 16. Incidentally, the basic configuration other than the single crystal block mounting the crystal wafers is the same as that of the first embodiment. As in the case of the first embodiment, only X-rays that satisfy a given angle condition are diffracted to form diffracted X-rays In, and the other X-rays pass through the crystal wafer. Since the crystal wafers mounted on the single crystal block are arranged in series in the direction of travel of the transmitted X-rays, the X-rays that have passed through the upstream crystal wafer continuously enter the next crystal wafer, and in the same manner, only X-rays that satisfy a given angle condition are diffracted to form diffracted X-rays In, and the other X-rays pass through the crystal wafer. In the third embodiment, the n crystal wafers are arranged, and thus, this phenomenon is repeated n times. At this time, when the angular difference Δω between the crystal wafers is adjusted to about 2dθD/n by use of a rotational mechanism 37, the diffracted X-ray image In obtained by the crystal wafers is identical to the diffracted X-ray image In obtained at each angle θn by scanning one analyzer crystal. Thus, the diffracted X-ray image obtained by the crystal wafers, detected at a time, can be substituted into Equation (9) to obtain the refraction angle without performing n rotational scans of the crystal wafers. Further, the phase-map of the sample can be obtained by integration process using obtained refraction angles. Incidentally, the spatial nonuniformity of the diffraction condition due to the crystal strain or the like remaining on the crystal wafers can be removed by the subtraction of the refraction angle distribution obtained according to the presence or absence of the sample, as in the case of the first embodiment. In FIG. 16, the Laue-case X-ray diffraction is used for beam splitting; however, the Bragg-case X-ray diffraction may also be used as is the case with the second embodiment. In this instance, the blurry of beam due to the Borrmann fan can be reduced, so that the spatial resolution can be improved. The rotational mechanism 37 for adjusting the angular difference between the crystal wafers requires high angular accuracy, as in the case of the first embodiment. Thus, as in the case of the first embodiment, a notch is cut in the single crystal block that support the crystal wafers, and the interval of the notch is opened or closed by a piezo to thereby adjust the angular difference. Also, in order to reduce the rotational drift of the angular difference over a long time by relaxation of stress of the piezo or the like, a measuring mechanism using a capacitance sensor or a laser may be built in, and active control for controlling a voltage applied to the piezo so as to reduce the drift may also be used. As described above, the third embodiment enables detecting the spatial distribution image of the refraction angle caused by the sample and phase-map, without performing the angular scan of the single crystal block which mounts the crystal wafers. This enables observation of the transmitted image of the sample with high sensitivity, in a short measurement time, with low X-ray damage, and without consideration of fluctuations in the incident X-ray intensity. The first to third embodiments can measure only the image that has passed through the sample (the transmitted image). Here given is an embodiment capable of nondestructive observation of the inside of the sample. The system is the same as those of the first to third embodiments, except for a sample holder 38 and a sample rotating mechanism 39. In the fourth embodiment, as shown in FIG. 17, a sample 55 is fixed to the sample holder 38, and can be rotated in a direction (x and z) perpendicular to the optical axis by the sample rotating mechanism 39. Also, in order to reduce the influence of the shape of the sample, the sample may also be immersed for measurement in a sample cell 40 filled with a liquid whose density is close to that of the sample. In the fourth embodiment, as shown in FIG. 18, the following procedure (1) to (3) is performed for the measurement. (1) Obtain the refraction angle θ caused by the sample by using the procedure shown in FIG. 13 (i.e., the measurement of the background distribution, the placement of the sample, and the main measurement). (2) Rotate the sample by Δr using the sample rotating mechanism 39. (3) Repeat the procedures (1) and (2) by the number n of required steps (=180°/Δr). (4) Further, in order to improve the accuracy of measurement, the sample may be withdrawn from the optical path, and after the measurement of the background distribution, the procedures (1) to (3) may be repeated required times. Then, after the measurement, a phase projection image is obtained by integration calculation of the spatial distribution image of the refraction angle θ acquired at each angle, and further, a sectional image of the sample of phase-contrast is reconstructed from the phase projection image by calculation using reconstruction algorism such as a filtered back projection method. The phase-contrast sectional image obtained through the calculation is displayed on a display unit for example under an operator command or the like. Here, as a method for obtaining the phase-map at each angle, the same method as the first embodiment for the two-point method or the same method as the second embodiment for the scan method may be used for measurement and calculation. Also, the Laue-case X-ray diffraction or the Bragg-case X-ray diffraction may be used for beam splitting. As described above, the fourth embodiment enables detection of the sectional image of the sample using as the contrast the phase caused by the sample, and thus enables nondestructive observation of the internal structure of the sample with high sensitivity, in a short measurement time, with low X-ray damage, and without consideration of fluctuations in the incident X-ray intensity or the like. The crystal wafers for use in the first to fourth embodiments are monolithically formed on the single crystal block, and thus, the size thereof (or a field of view) is limited by the diameter of the crystal ingot that forms a matrix of the single crystal block, which makes it difficult to ensure a size of 2 by 2 centimeters square or more. Here given is an example of an imaging system in which crystal wafers formed on multiple crystal blocks are used to enable ensuring a field of view of 2 cm or more. As shown in FIG. 19, crystal wafers 41 and 42 are formed on separate crystal blocks 43 and 44, respectively. The crystal blocks are mounted on rotational mechanisms 45 and 46, respectively, and further, the rotational mechanisms are mounted on one crystal block positioning mechanism 47. The crystal wafers are adjusted to have the same angular difference as that of the first and second embodiments by use of the rotational mechanisms 45 and 56. In this instance, the angular difference must be controlled with high accuracy, and thus, a small-size horizontal rotating table using a tangential bar may be used. Also, in order to reduce drift or the like, a measuring mechanism using a laser or a high-accuracy encoder can be used to control rotation so that the measured value thereof is fixed. A precise positioning table using a tangential bar can be used as the crystal block positioning mechanism 47, as in the case of the first and second embodiments. Incidentally, a table having a thicker rotation shaft and a higher load resistance, as compared to that used in the first and second embodiments, is suitable in order to mount the rotational mechanisms 45 and 56 and the single crystal blocks 43 and 44 with high stability. The measurement is performed in the same manner as the first embodiment, each obtained image is used for calculation of the spatial distribution image of the refraction angle and phase-map, and each projection image or sectional image is displayed on the display unit 21 under an operator command or the like. Also, the sample holder 16 and the sample holder positioning mechanism 17 may be replaced by the same as those used in the fourth embodiment to obtain the sectional image of the sample by the method of the fourth embodiment. As described above, even if the sample is of large size, the fifth embodiment enables detecting the projection image and the sectional image using as the contrast the refraction angle and the phase caused by the sample, and thus enables nondestructive observation of the internal structure of the sample with high sensitivity, in a short measurement time, with low X-ray damage, and without consideration of fluctuations in the incident X-ray intensity or the like. FIG. 20 shows an embodiment of a mammography system (or a breast cancer diagnosis system) as an example of a diagnosis system that exploits the feature of the present invention, that is, the advantage of “being highly sensitive particularly to light elements and thus being suitable for observation of biological soft tissues consisting mainly of the light elements.” The diagnosis system requires an X-ray source, a means for minimizing X-ray dosage due to X-ray irradiation, a large field of view that allows obtaining an object at a time, and high stability that allows obtaining the same image even if measurement is performed many times. Thus, the sixth embodiment is provided with an X-ray source 48, a means for preventing X-ray irradiation of a region other than an irradiation region of the object, such as an X-ray shield wall 49 and an X-ray shield cover 50, and an asymmetric crystal plate 51 for enlarging an X-ray beam, in addition to the basic configuration of the fourth embodiment. The X-ray shield wall 49 which is disposed between the X-ray source 48 and the asymmetric crystal plate for enlargement 51, and which serves to shield unnecessary X-rays of X-rays emitted from the X-ray source 48, is made of a thick wall containing lead or the like, and can shield 100% of the X-ray intensity. The X-ray shield cover 50 serves to cover the overall main constituent part of the system, including the asymmetric crystal plate for enlargement 51, the crystal wafers, and so on, and prevents irradiation of an object 52 or the X-ray imager 18 with scattered X-rays produced by the crystals. Since the intensity of the scattered X-rays is not very strong, an acrylic sheet containing lead, an iron sheet laminated with thin lead, or the like is used for this shield cover. A part for placement of the object 52 within the X-ray beam is provided with a concave portion as shown in FIG. 20, and a part of the object 52, other than a part to be irradiated with beams, is set not to be irradiated with the X-rays. Strain generated between the asymmetric crystal plate for enlargement 51 and the diffraction plane interval of the crystal wafer 41 caused by heat generation of a subject 53, or the like is reduced by making a distance of 30 cm or more between the subject 53 and the asymmetric crystal plate for enlargement 51 and between the subject 53 and the crystal wafer 41. Also, the influence of floor vibration or the like caused by replacement of the subject 53 is reduced by mounting, on the same antivibration mount 54, the asymmetric crystal plate for enlargement 51 and the single crystal blocks 43 and 44 which mount thereon the crystal wafers 41 and 42, respectively. The antivibration mount 54 is also of concave configuration in the vicinity of the subject 53, and has a structure such that the subject does not come into contact with the antivibration mount. In breast cancer diagnosis, the thickness of the object (or the breast) varies greatly among individuals. Thus, the thicknesses of individual objects are premeasured, and the optimum energy of X-rays and a diffraction plane to be used are determined in advance. The measurement is performed following a flowchart of FIG. 13, as described with reference to the first embodiment. 1: beam splitter, 2: mirror, 3: analyzer, 4: incident X-ray, 5: beam, 6: beam, 7: interference beam, 8: interference beam, 9: sample, 10: single crystal made of flat sheet, 11: crystal wafer, 12: crystal wafer, 13: single crystal block, 14: rotational mechanism, 15: crystal block positioning mechanism, 16: sample holder, 17: sample holder positioning mechanism, 18: X-ray imager, 19: controller, 20: processing unit, 21: display device, 22: X-ray, 23: diffracted X-ray, 24: transmitted X-ray, 25: diffracted X-ray, 26: transmitted X-ray, 27: crystal wafer, 28: crystal wafer, 29: single crystal block, 30: X-ray, 31: diffracted X-ray, 32: transmitted X-ray, 33: diffracted X-ray, 34: transmitted X-ray, 35: rotational mechanism, 36: single crystal block, 37: rotational mechanism, 38: sample holder, 39: sample rotating mechanism, 40: sample cell, 41: crystal wafer, 42: crystal wafer, 43: crystal block, 44: crystal block, 45: rotational mechanism, 46: rotational mechanism, 47: crystal block positioning mechanism, 48: X-ray source, 49: X-ray shield wall, 50: X-ray shield cover, 51: asymmetric crystal plate for enlargement, 52: object, 53: subject, 54: antivibration mount, 55: sample, 56: measuring mechanism, 58: piezo
	abstract	Example embodiment damping devices may include a housing capturing a piston. The housing may be filled and/or able to be filled with a damping fluid compatible with the nuclear reactor coolant, so that a leak from the housing or coolant passing into the housing does not damage the reactor or example embodiment devices. Example embodiments may further include one or more springs that provide an elastic force opposing movement between the piston and housing. A shaft of the piston and an end of the housing may be connected to two nuclear reactor components with relative motion or vibration to be damped. Example methods may use example embodiment damping devices to reduce and/or prevent relative motion and vibration among components of a nuclear reactor.
051204886	abstract	The invention relates to a sealing sleeve for sealing a leak in, for example, a pipe, a pipe socket or the like in a nuclear reactor. The sleeve comprises a bellows-like mid-portion (1) with annular ends, at least these or part of these (2) being made of a memory metal with a suitable transition temperature. At a temperature above the transition temperature, that part of these annular ends which consists of memory metal has been given an inner diameter suitable for achieving sealing around the relevant pipe section on each side of the leak. The mentioned part of the ends has thereafter, at a temperature below the transition temperature, been deformed into a diameter which permits the sleeve to be freely fitted onto the pipe. In fitted position, the sleeve is then heated to above the transition temperature, the memory metal then striving to recover its previous shape and shrinks the sleeve so as to obtain sealing.
	claims	1. A control system for a nuclear facility comprising:a detecting sensor provided in a nuclear facility and configured to output an abnormality detecting signal at the time of occurrence of an abnormality in the nuclear facility;a main control device including a programmable processor configured to output a normal actuating signal when a unit is actuated normally in consequence of controlling the unit provided in the nuclear facility to a safe side based on the abnormality detecting signal; andan auxiliary control device, as an auxiliary of the main control device, configured to output an auxiliary actuating signal to actuate the unit to a safe side in a case where the auxiliary control device determines from output results of the abnormality detecting signal and the normal actuating signal that the unit is not actuated normally for the abnormality in the nuclear facility, whereinthe auxiliary control device includes:a NOT circuit connected to an output side of the main control device, and configured to output a signal when the normal actuating signal is not input, and not to output the signal when the normal actuating signal is input; anda first AND circuit configured not to output the auxiliary actuating signal when at least one of the signal from the NOT circuit and the abnormality detecting signal is not input, and configured to output the auxiliary actuating signal when the signal from the NOT circuit and the abnormality detecting signal are input,wherein the detecting sensor is connected to an input side of the first AND circuit via a delay circuit and the main control device is connected to another input side of the first AND circuit via the NOT circuit. 2. The control system for a nuclear facility according to claim 1, wherein the delay circuit is configured to delay output of the abnormality detecting signal to the first AND circuit as much as predetermined time from reception of the abnormality detecting signal by the main control device to output of the normal actuating signal to the first AND circuit. 3. The control system for a nuclear facility according to claim 1, further comprising:a first manual manipulating unit configured to output an allowing signal allowing output of the auxiliary actuating signal by manual manipulation, whereinthe auxiliary control device further includes a second AND circuit configured to output the auxiliary actuating signal when the auxiliary actuating signal from the first AND circuit and the allowing signal are input, and not to output the auxiliary actuating signal when at least one of the auxiliary actuating signal from the first AND circuit and the allowing signal is not input. 4. The control system for a nuclear facility according to claim 3, further comprising:a second manual manipulating unit configured to output a manual actuating signal actuating the unit provided in the nuclear facility to a safe side by manual manipulation, whereinthe auxiliary control device further includes an OR circuit configured to output a second auxiliary actuating signal when at least one of the auxiliary actuating signal output from the second AND circuit and the manual actuating signal is input, and not to output the second auxiliary actuating signal when the auxiliary actuating signal output from the second AND circuit and the manual actuating signal are not input. 5. The control system for a nuclear facility according to claim 1, wherein the nuclear facility includes a nuclear reactor having inside a core, a containment housing the nuclear reactor, and the unit,wherein the unit includes a core damage preventing unit preventing damage of the core and a vessel breakage preventing unit preventing breakage of the containment, andwherein the auxiliary control device outputs the auxiliary actuating signal to actuate the core damage preventing unit and the vessel breakage preventing unit to a safe side. 6. The control system for a nuclear facility according to claim 1, wherein the main control device includes a digital facility executing software on hardware, andwherein the auxiliary control device is an analog facility configured by connecting respective junctions of electronic components by wires.
	description	This application claims the benefit of U.S. Provisional Application No. 61/055,025, filed on May 21, 2008. The entire teachings of the above application are incorporated herein by reference. An electron beam emitter commonly includes an electron gun or generator for generating electrons, which is positioned within a vacuum chamber. The vacuum chamber has an electron beam exit window foil at one end through which the electrons from the electron gun are accelerated by a voltage potential imposed between the electron gun and the exit window foil. The electron gun can include a housing enclosing one or more elongate line source filaments, for example two, which produce electrons when electrical power is passed through the filaments. The electron gun housing generally includes a grid pattern of small round holes below the filaments which allow the electrons produced by the filaments to exit the electron gun housing for acceleration out the exit window foil. Typically, the electrons that reach the exit window foil from each filament are focused in a line pattern resembling or corresponding to the narrow elongate shape of the filaments. For example, this can be seen in the graph of FIG. 1, which depicts a typical pattern of electrons at the exit window foil from an electron gun having two elongate filaments, where the electrons are concentrated in two narrow elongate lines 8 corresponding to the two filaments, while the surrounding areas 9 have lower concentrations of electrons. Having a nonuniform electron distribution with such higher and lower intensity electron spots or regions can limit the overall beam power used. In addition, in cases where the electron beam emitter is operated close to a product that is being irradiated or within a low pressure or vacuum environment, with little or no air present to scatter the electrons, the electrons reaching the product could in some situations still be in the pattern depicted in FIG. 1, resulting in uneven irradiation. The present invention can provide an electron beam emitter including an electron generator for generating electrons. The electron generator can have a housing containing at least one electron source for generating the electrons. The at least one electron source has a width. The electron generator housing can have an electron permeable region spaced from the at least one electron source for allowing extraction of the electrons from the electron generator housing. The electron permeable region can include a series of narrow elongate slots and ribs formed in the electron generator housing and extending laterally beyond the width of the at least one electron source. The electron permeable region can be configured and positioned relative to the at least one electron source for laterally spreading the electrons that are generated by the at least one electron source. In particular embodiments, the electron source can be an elongate electron source. The slots can be at an angle ranging from about 30° to 90° relative to the elongate electron source, or can be at an acute angle. The slots can be about ⅛ to 3/16 inches wide, and the ribs can be about 0.030 to 0.040 inches wide. The electron permeable region can have an elongate length and width, and the length of the electron permeable region can have a longitudinal axis. The slots can be positioned on a pitch of about ¼ inches relative to the longitudinal axis. The electron permeable region can have a slot width to rib width ratio of about 3 to 1 to about 6 to 1. The electron generator housing can be made of sheet metal and have a planar portion, and the electron permeable region can be integrally formed within the planar portion. The electron generator can be positioned within a vacuum chamber having an electron beam exit window, and spaced from the exit window for accelerating the electrons out the exit window. The slots and ribs of the electron permeable region can be configured to allow an electrical field extending between the electron generator housing and the exit window to penetrate into the electron generator housing through each slot and laterally relative to the at least one electron source to form a transverse electrical field region surrounding the at least one electron source for laterally spreading the electrons relative to the at least one electron source. In some embodiments, the exit window can include a support plate supporting an exit window foil. The support plate can have a series of holes therethrough for allowing passage of the electrons. The holes can be continuously angled outwardly moving toward two opposite ends. In some embodiments, the electron permeable region can include first and second rows of slots, where the slots of the first row are angled relative to the slots of the second row. The present invention can also provide an electron beam emitter, including a vacuum chamber having an electron beam exit window. An electron generator for generating electrons for acceleration out the exit window can be positioned within the vacuum chamber and spaced from the exit window. The electron generator can have a housing containing at least one electron source for generating the electrons. The at least one electron source has a width. The electron generator housing can have an electron permeable region spaced from the at least one electron source for allowing extraction of the electrons from the electron generator housing. The electron permeable region can include a series of narrow elongate slots and ribs integrally formed in a planar sheet metal portion of the electron generator housing and extending laterally beyond the width of the at least one electron source. The slots and ribs of the electron permeable region can be configured to allow an electrical field extending between the electron generator housing and the exit window to penetrate into the electron generator housing through each slot and laterally relative to the at least one electron source to form a transverse electrical field region surrounding the at least one electron source for laterally spreading the electrons relative to the at least one electron source before extraction from the electron generator housing. In particular embodiments, the electron source can be an elongate electron source. The slots can be at an angle ranging from about 30° to 90° relative to the elongate electron source, or can be at an acute angle. The slots can be about ⅛ to 3/16 inches wide, and the ribs can be about 0.030 to 0.040 inches wide. The electron permeable region can have an elongate length and width, and the length of the electron permeable region can have a longitudinal axis. The slots can be positioned on a pitch of about ¼ inches relative to the longitudinal axis. The electron permeable region can have a slot width to rib width ratio of about 3 to 1 to about 6 to 1. In some embodiments, the exit window can include a support plate supporting an exit window foil. The support plate can have a series of holes therethrough for allowing passage of the electrons. The holes can be continuously angled outwardly moving toward two opposite ends. In some embodiments, the electron permeable region can include first and second rows of slots, where the slots of the first row are angled relative to the slots of the second row. The present invention can also provide a method of dispersing electrons in an electron beam emitter. The electrons can be generated with an electron generator. The electron generator can have a housing containing at least one electron source for generating the electrons. The at least one electron source has a width. The electron generator housing can have an electron permeable region spaced from the at least one electron source for allowing extraction of the electrons from the electron generator housing. The electron permeable region can be configured and positioned relative to the at least one electron source for laterally spreading the electrons that are generated by the at least one electron source. The electron permeable region can include a series of narrow elongate slots and ribs formed in the electron generator housing and extending laterally beyond the width of the at least one electron source. In particular embodiments, the electrons can be generated with an elongate electron source. The slots can be positioned at an angle ranging from about 30° to 90° relative to the elongate electron source, or can be at an acute angle. The slots can be formed about ⅛ to 3/16 inches wide, and the ribs can be formed about 0.030 to 0.040 inches wide. The electron permeable region can be provided with an elongate length and width, and the length of the electron permeable region can have a longitudinal axis. The slots can be positioned on a pitch of about ¼ inches relative to the longitudinal axis. The electron permeable region can be provided with a slot width to rib width ratio of about 3 to 1 to about 6 to 1. The electron generator housing can be formed from sheet metal with a planar portion, and the electron permeable region can be integrally formed within the planar portion. The electron generator can be positioned within a vacuum chamber having an electron beam exit window, and spaced from the exit window. Electrons extracted from the electron generator can be accelerated out the exit window. The slots and ribs of the electron permeable region can be configured to allow an electrical field extending between the electron generator housing and the exit window to penetrate into the electron generator housing through each slot and laterally relative to the at least one electron source to form a transverse electrical field region surrounding the at least one electron source for laterally spreading the electrons relative to the at least one electron source. In some embodiments the exit window can include a support plate supporting an exit window foil. The support plate can be provided with a series of holes therethrough for allowing passage of the electrons. The holes can be continuously angled outwardly moving towards two opposite ends for matching trajectories of the electrons. In some embodiments, the electron permeable region can be provided with first and second rows of slots, where the slots of the first row are angled relative to the slots of the second row. The present invention can also provide a method of irradiating a product with an electron beam emitter. Electrons can be generated with an electron generator. The electron generator can have a housing containing at least one electron source for generating the electrons. The at least one electron source has a width. The electron generator housing can have an electron permeable region spaced from the at least one electron source for allowing extraction of the electrons from the electron generating housing. The electron permeable region can include a series of narrow elongate slots and ribs formed in the electron generator housing and extending laterally beyond the width of the at least one electron source. The electron permeable region can be configured and positioned relative to the at least one electron source for laterally spreading the electrons that are generated by the at least one electron source. The product and the electron beam emitter can be moved relative to each other at an acute angle relative to the slots and ribs of the electron permeable region for irradiating the product with the electrons. FIGS. 2 and 3 depict an embodiment of an electron beam emitter, apparatus or device 10 in the present invention. The electron beam emitter 10 can have a vacuum chamber 12, which can be hermetically sealed. The vacuum chamber 12 can have a housing 12a with an electron gun or generator 24 positioned within the interior 22 of the housing 12a and spaced from the walls of housing 12a for generating electrons. The electron gun 24 can include an electron gun or generator housing or enclosure 26. The electron gun housing 26 can contain, enclose, or surround one or more electron generating sources or members 30 positioned within the interior 28 of housing 26. For example, two sources 30 are shown in FIG. 3 and will be described herein as such, but it is understood, that less than or more than two can be employed. The electron generating sources 30 can be elongate line electron sources, including filaments, or other suitable elongate line sources which can have a narrow width or diameter, as known in the art. Electrical power from an electron generating power supply 13 can be passed through the electron sources 30 causing the electron sources 30 to produce electrons e−. The vacuum chamber 12 can include an electron beam exit window 14 having a support grid 18 with holes 20 therethrough, which supports an exit window foil 16. The exit window 14 can be generally rectangular in shape. Electrons produced by the electron sources 30 in the electron gun 24 can be accelerated out the exit window 14 in an external electron beam 15 (FIG. 5) by imposing a high voltage electrical potential difference between the electron gun housing 26 and the exit window 14 with a high voltage power supply 11, which forms a high voltage electrical field 23 (FIG. 10) between the electron gun housing 26 and the exit window 14. Reference numeral 23 points to an equal potential line within electrical field 23. The housing 26 of the electron gun 24 can have an electron permeable region 32 from which the electron sources 30 are spaced. The electron sources 30 can each longitudinally extend along a longitudinal axis 31. The longitudinal axes 31 can be parallel to the electron permeable region 32, and can be on a common plane. The electron gun housing 26 and electron permeable region 32 can be aligned and spaced from the exit window 14 along an axis A which can be along a longitudinal axis of vacuum chamber 12. The electron gun housing 26 and the electron permeable region 32 can be configured for evenly dispersing the electrons e− in a transverse or lateral manner relative to the electron sources 30 to be wider than the diameter or width WE of the electron sources 30 within the electron gun housing 26, before reaching the electron permeable region 32, as seen in FIG. 4, and therefore before reaching the exit window 14. In addition, the electrons can be evenly dispersed longitudinally relative to electron sources 30, as seen in FIG. 5. By dispersing or spreading the electrons transverse to the line electron sources 30 in an internal electron beam 15a (FIG. 4) within the vacuum chamber 12 before reaching the exit window 14, a more uniform electron distribution can be obtained, and peak power or high intensity spots on the exit window 14 can be reduced, which can permit a higher overall beam power to be used. In addition, more area of the exit window 14 can be utilized and maximized for electron transmission. By averaging electron beam power across the exit window, micro uniformities can be eliminated or reduced. The electron gun 24 can also passively spread the electrons from electron sources 30 without requiring an additional external power source for separately shaping the electrons. The electron sources 30 can be for example, elongate filaments formed of suitable materials, for example tungsten, which can cause free electrons to form thereon when heated by passing electrical power therethrough for example, 5 to 50 watts, and can have a width WE or diameter in the range of about 0.005 to 0.020 inches, and can be in some embodiments about 0.009 inches. The electron sources 30 can be also formed of other suitable materials, including lanthanum hexaboride, and can have other widths or diameters. The exit window foil 16 can be a metallic or non metallic foil, for example, titanium, aluminum, beryllium, stainless steel, copper, gold, silver, diamond, ceramics, or combinations thereof Common thicknesses of the exit window foil can be between about 4-13 microns thick, for example 7-10 microns, but can be lower or higher depending upon the voltage and the materials. The voltage potential between the electron gun housing 26 and the exit window 14 can range between 1 KV and 500 KV, but can be lower or higher, and can be commonly between 80 KV and 150 KV. Referring to FIGS. 6-11, the electron permeable region 32 can include a series of lateral or traverse slots 32a extending across, laterally or transverse relative to the electron sources 30 and axes 31. The slots 32a can be positioned side by side to collectively form the electron permeable region 32 and can extend along a longitudinal axis 25 that is parallel to longitudinal axes 31. The slots 32a can be integrally formed on a flat, planar, lower, bottom, axial, end or side portion 26a of the housing 26 and on a plane parallel to the electron sources 30, and centered relative to axis A. As a result, the electron permeable region 32 can extend in a planar fashion along portion 26a and axis 25. The transverse slots 32a of the electron permeable region 32 can be closely arranged together side by side in a pattern having a length L extending along axis 25, and a width or lateral distance D, on the flat planar portion 26a of housing 26. The electron permeable region 32 can be generally rectangular. The length of the electron sources 30 along axes 31 can be about the same as the length L of electron permeable region 32, and in some situations, can be slightly longer. Electrons extracted from the housing 26 through the electron permeable region 32 can have a length and width generally matching or corresponding to the length L and width D. The slots 32a can be chevron slots separated from each other by narrow ribs or webs 33. The slots 32a can be angled at an acute angle α relative to axis 25 and/or axes 31 and electron sources 30, which can often range from 30° to 90°, and in some embodiments, 45° to 60°. In some embodiments, angles less than 30° can be used. The ribs 33 can be at the same angle α. The electron permeable region 32 and slots 32a can laterally extend past or beyond the width WE on one or both lateral sides of each electron source 30 or axis 31 by a lateral or transverse distance X (FIGS. 8 and 9). In prior art electron guns which have a series of narrow round holes below elongate filaments, the electrons generated by the filaments tend to focus into a narrow beam that mostly pass through the narrow holes that are aligned with the elongate filament, thereby concentrating the electrons into a narrow line, such as seen in FIG. 1. In contrast, the transverse slots 32a can allow the high voltage electrical field 23 that is imposed between the electron gun housing 26 and the exit window 14 to leak or extend into the electron gun housing 26 by penetrating into the electron gun housing 26 at each slot 32a, to form a transverse or lateral electrical field region 29 extending a distance or depth f (FIG. 9) within the electron gun housing 26, which can extend along as well as transverse or lateral to, and surround the electron sources 30 or axes 31. Reference numeral 29 points to an equal potential line of transverse electrical field region 29. As seen in FIGS. 9-11, the depth f of the transverse electrical field region 29 can extend into the electron gun housing 26 beyond the location of the electron sources 30, or past the distance or height h. This can surround, immerse, position or locate the electron sources 30 within the transverse electrical field region 29. The size and strength of the transverse electrical field region 29 can be optimized by the size or length and width of the slots 32a and ribs 33. There are typically no components located between portion 26a of the electron gun 24 and the exit window 14 along axis A to interfere with or disturb the shape of the electrical field 23 imposed between the electron gun housing 26 and the exit window 14. The transverse electrical field region 29 is at a more positive electrical potential than the electron sources 30 to cause or allow elections e− from the electron sources 30 to spread laterally relative to the electron sources 30 and axes 31, to be wider than the width WE of the electron sources 30, as shown in FIGS. 4, 9 and 11, and disperse in an even distribution instead of focusing into a narrow line when exiting housing 26. Such an even distribution or dispersion can be seen in the graph of FIG. 12 where the pattern of electrons 34 at the exit window foil 16 is evenly distributed both along the length and laterally. FIG. 13 depicts another possible electron distribution and pattern of electrons 34 on an exit window 14. When the electrons extracted from the electron gun housing 26 in an internal electron beam 15a for acceleration out the exit window 14 are in such a laterally dispersed manner, the electron beam 15 exiting the exit window 14 can also be laterally dispersed. The even electron distribution can result in uniform irradiation of substances or products by electron beam emitter 10. By positioning the electron sources 30 within the transverse electrical field region 29, electrical potential wells 35 (FIG. 9) can form around the electron sources 30. The electrical potential wells 35 are regions that are more electrically positive than the electron sources 30, which initially accelerates and disperses the electrons radially away from each electron source 30 in a circular pattern or in all directions (FIGS. 4 and 11), before being directed to the electron permeable region 32 by the effect of electrical field 23. Such initial acceleration can laterally disperse the electrons relative to electron sources 30 before reaching the electron permeable region 32 for extraction from the electron housing 26. The deeper or larger the potential well 35, the greater distance the electrons can move radially outwardly and then spread or disperse laterally. Electron sources 30 positioned closer to the electron permeable region 32 and electrical field 23, and having a small height h (FIG. 9), can have larger potential wells 35 than if positioned further away (having a larger height h). The strength of the transverse field region 29 closer to the electron permeable region 32 is typically stronger than at locations further away. FIG. 11 depicts one example of electrical field potential levels within and outside an embodiment of the electron gun housing 26 where particular locations in the transverse field region 29 can range from 10V to 30V with respect to the electron gun housing 26, with 10V locations being further away from the electron permeable region 32 and slots 32a, and where the potential of electrical field 23 outside the electron gun housing 26 can be at least 1 KV. The electron sources 30 can be at 0-20 volts with respect to the electron gun housing 26. In other embodiments, referring to FIG. 10, the transverse field region 29 within electron gun housing 26 can have field regions ranging from about 10V to 50V with respect to the electron gun housing 26, and the potential of electrical field 23 outside housing 26 can range from about 5 to 150 KV with respect to the electron gun housing 26. In still other embodiments these can vary. The slots 32a can have a length and width WS wide enough to form a transverse field region 29 sufficiently extending to and around or beyond the electron sources 30, as well as to provide sufficient openings for the passage of dispersed electrons from the electron gun housing 26. In addition, the ribs 33 can be made sufficiently thin to minimally impede the path of the electrons extracted from the housing 26 of the electron gun 24, while at the same time, can be sufficiently close enough together to provide uniform voltage regions across the electron permeable region 32 to uniformly accelerate the dispersed electrons in the internal electron beam 15a from the electron gun 24 to the exit window 14. A suitable slot width, rib width, and spacing configuration or ratio can provide an optimum combination of the size and intensity of the transverse electrical field region 29 for the lateral electron dispersion relative to the electron sources 30, passage of the electrons through the electron permeable region 32 for extraction from the electron gun 24, and uniform acceleration from the electron gun 24 to the exit window 14. The slots 32a can be integrally formed within a planar sheet portion 26a of housing 26 which allows suitable slot width to rib width ratios to be made along axis 25 in a planar fashion integrally within portion 26a. As a result, the electron permeable region 32 can be flush with portion 26a, and not protrude from the interior and exterior surfaces of portion 26a. The slots 32a can be formed on portion 26a, for example, by machining, such as by milling with a CNC machine, by stamping with a die, by EDM, or other suitable methods. The integrally formed electron permeable region 32 also can be laterally surrounded by laterally extending flush planar surfaces of portion 26a. The integral configuration of electron permeable region 32 can provide consistency in the shape of the transverse field regions 29 which are formed within the interior 28 of electron gun housing 26. The electron gun housing 26 in some embodiments can be formed of two or more pieces that can be assembled together. The portion 26a of the housing 26 in some embodiments can be part of a housing portion 27 (FIGS. 6 and 7) which can be circular or generally cup shaped, and can be made of sheet metal. The housing portion 27 can include a series of holes 38 for assembly with other components of the electron gun 24. The length L and width D of the electron permeable region 32 of housing 26 can vary depending upon the size of emitter 10, exit window 14, and the length, number and spacing of the electron sources 30. For example, the length L of electron permeable region 32 in some embodiments of FIGS. 6 and 7 can commonly range between about 5 and 10 inches long, and in some examples, can be about 6¾ inches, about 7¼ inches and about 7½ inches long. In other embodiments, length L can be less than 5 inches or greater than 10 inches. The width D of the electron permeable region 32 for two electron sources 30 or filaments can commonly be about 1½ to 2½ inches wide, with about 2 inches being common, and in one embodiment is about 1.8 inches. The length and width of the internal beam 15a of electrons passing through the electron permeable region 32 can generally have dimensions corresponding to the length L and width D. In other embodiments, width D can be less than 1½ inches and greater than 2½ inches. In some embodiments, the slots 32a can have a constant or consistent width Ws which can commonly be about ⅛ to 3/16 inches, for example, 0.156 inches, and can be at an angle of 60° relative to axis 25, with a pitch P of about ¼ inches, for example 0.22 inches. In some embodiments, the width Ws of slots 32a can be less than ⅛ inches or greater than 3/16 inches, and can be at other angles α, and at pitches P more than or less than ¼ inch. The length of the slots 32a can vary depending upon the situation at hand, as well as the angle α, and can often be about 1½ to 2 inches. The ribs 33 can also be at angle α, and separate or space the slots 32a from each other. Ribs 33 can often range between 0.030 inches to 0.040 inches thick, and in some embodiments can be less than 0.030 inches or more than 0.040 inches. The ribs 33 can be about 1/32 of an inch thick, such as 0.034 or 0.035 inches. For ribs 33 that are 0.034 inches thick positioned between slots 32a having a width Ws of 0.156 inches on a longitudinal pitch P of 0.22 inches, the electron permeable region 32 can have a slot width to rib width ratio of about 4.5 to 1. In other embodiments, the slot width to rib width ratio can range from about 3 to 1 to about 6 to 1. Depending upon the length L of electron permeable region 32, there can often be for example, about 30 to 40 slots 32a, for example, 33 or 35 slots 32a. The ends of the slots 32a can be rounded, and some slots 32a near the ends of the electron permeable region 32 can be truncated or shorter to make the electron permeable region 32 generally rectangular in shape. In some embodiments, the electron permeable region 32 can extend laterally relative to the diameter or width WE of electron sources 30 and axes 31 by a distance X of about ⅜ to about ½ inch, and the electron sources 30 can be spaced apart from each other by about ⅝ to about 1 inch (about 17-24 mm). With the slots 32a extending such a distance X, the electrons can be spread about ⅜ to about ½ inch to either side of an axis 31. In some embodiments, the electron sources 30 can be narrow filaments, for example, 0.009 inches thick, such that the electrons are spread laterally relative to the width WE by approximately the distance X. The distance X can vary depending upon the width D of the electron permeable region 32, and the number of electron sources 30 and height h. The electron sources 30 in some embodiments can be spaced from the electron permeable region 32 by a distance or height h of about 2 to 12 mm (about 0.08-0.5 inches), such as 2, 3, 4, 7, 10, and 12 mm (0.08, 0.12, 0.16, 0.28, 0.4 and 0.47 inches), to be within the desired location of the transverse field region 29 for desired field strength or desired lateral electron spreading. Heights h of 2-6 mm are common, for example 4 mm. Referring to FIGS. 14 and 15, the support plate 18 of exit window 14 can be formed of copper or a copper alloy, and can have a rectangular grid of round holes 20 for allowing electrons extracted from the electron gun 24 to pass therethrough for reaching and passing through exit window foil 16. Both the support plate 18 and the exit window foil 16 can be rectangular in shape. The holes 20 can be gradually or progressively continuously angled outwardly moving toward the opposite ends, as seen in FIG. 15, to match electron beam trajectory and achieve efficient or best transmission. In other embodiments, the support plate 18 for emitter 10 can include only holes 20 that are straight. In still other embodiments, the support plate 18 can have slotted holes which are sized, shaped, positioned and oriented to correspond or match the slots 32a in the electron gun 24. For example, the holes 20 in support plate 18 can be shaped and oriented, with a pattern such as the slots 32a in FIG. 7. FIG. 16 depicts another embodiment of a housing portion 27. The electron permeable region 32 can include slots 32a that are arranged or positioned in two rows 36a extending on opposite sides of axis 25 parallel or side by side to form a double chevron or angled slot pattern 36. The slots 32a in the two rows 36a can be angled relative to each other to form a vee shaped chevron pattern. The slots 32a in each row 36a can be angled at an acute angle α relative to axis 25, which can in some embodiments be at the same angle and can be about 45°. The slots 32a can be spaced apart by a longitudinal pitch P relative to axis 25 of about ¼ inch (such as 0.27 inches). The slots 32a can have a width Ws of about ⅛ to 3/16 inches (for example, 0.156 inches) and the ribs 33 can be about 0.030 to 0.040 inches, or 1/32 inches wide (for example 0.034 inches). The length L of electron permeable region 32 can be about 7½ inches and the width D can be about 2 inches, for example 1.8 inches. The width D1 of each row 36a can be about ¾ to 1 inches wide, for example 0.9 inches. In other embodiments the dimensions of slots 32a, ribs 33, angle α and electron permeable region 32 can vary, for example, as previously mentioned. It is understood that the configuration, dimensions and angles of the various electron permeable regions 32 shown and described, can vary depending upon the size of the emitter 10, as well as the number and length or size of electron sources 30. Referring to FIG. 17, in another embodiment, the electron permeable region 32 can include two chevron or angled slot patterns 36 joined together at the center, and the slots 32a in each row 36a can also be connected or joined together. The slots 32a can angle outwardly toward the ends. The electron permeable region 32 can be integrally formed within a rectangular piece of sheet metal which is assembled to a corresponding opening in the electron gun housing 26. This design can be employed with the other patterns of slots 32a disclosed. Referring to FIG. 18 in yet another embodiment, the electron permeable region 32 can have two rows of slots 32a, 42a and 42b, longitudinally joined together and positioned along respective longitudinal axes 25a and 25b. The axes 25a and 25b can be offset from each other, and the electron sources 30 for each row 42a and 42b can also be offset from each other. The slots 32a can in some embodiments have a length of about 1½ inches. Referring to FIG. 19, in another embodiment, the electron permeable region 32 can have a pattern 40 with slots 32a which are at a right angle or 90° to axis 25. Referring to FIG. 20, electron beam emitters of other various configurations can include the electron permeable regions 32 of the present invention. For example electron beam emitter 50 can have an electron gun 24 and exit window 14 aligned along axis A which is lateral or normal to the longitudinal axis B of the emitter 50. FIG. 21 depicts another embodiment of an electron beam emitter 55, and is shown irradiating a moving product or web 56. Although in some embodiments, the ribs 33 between the slots 32a can form slight intermittent interruptions in the electrons exiting the electron gun housing 26 along axis 25, under most circumstances, sufficient electron scattering or dispersion usually occurs, resulting in generally even electron distribution by the time the electrons reach the product to be irradiated. However, in cases where the electron beam emitter is used in a low pressure or vacuum environment and/or close to a moving product or web 56, by having slots 32a in the electron gun housing 26 that are angled at angle α, if there is any chance of electron masking by ribs 33, or in embodiments where the support plate 18 of the exit window 14 has slots 20 that are oriented to match the orientation of slots 32a, a moving product or web 56 can be irradiated with the electron beam emitter 55 oriented such that the product 56 moves relative to overlapping angled slots 32a of the electron gun housing 26, instead of parallel to slots 32a, as a measure to ensure uniform irradiation. Such irradiation can also be conducted with other electron beam emitters in the present invention. While this invention has been particularly shown and described with references to example embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the scope of the invention encompassed by the appended claims. For example, although the electron sources 30 and the electron permeable region 32 are shown to extend along straight axes 31 and 25, in other embodiments, the electron sources 30 can have configurations that are nonlinear, such as curved, angled, are not elongate, or are wide. In such situations, electron permeable region 32 can be correspondingly shaped to disperse the generated electrons, and the exit window 14 can be also correspondingly shaped. In addition, although the electron permeable region 32 has been shown to have a length L and width D that generally matches the electron sources 30, the length L and D can be varied to form a shaped dispersion pattern, or can be nonlinear. Although embodiments of the electron permeable region 32 have been shown to be integrally formed in sheet metal, in other embodiments, the electron permeable region can be formed by fabricating or assembling components together.
047626666	abstract	A swing gate closure assembly for nuclear reactor tipoff assembly wherein the swing gate is cammed open by a fuel element or spacer but is reliably closed at a desired closing rate primarily by hydraulic forces in the absence of a fuel charge.
	summary
	claims	1. A modular power unit for a work machine, comprising:an engine;a generator connected to the engine;a battery connected to the engine but not the generator; anda heat exchanger foldably connected to the engine, with the engine, generator, battery and heat exchanger being self-contained, unitary and configured to be removable and replaceable from an engine compartment of the work machine as a single unit without removing any other modules or parts of the work machine. 2. The modular power unit for a work machine of claim 1, wherein the heat exchanger foldably connected to the engine is positioned directly over the battery and the engine. 3. The modular power unit for a work machine of claim 1, wherein the heat exchanger foldably connected to the engine is removed to allow access to the battery and the engine. 4. The modular power unit for a work machine of claim 1, wherein the modular power unit is not integrated with the work machine. 5. The modular power unit for a work machine of claim 1, wherein the heat exchanger foldably connected to the engine is not removed from the modular power unit when the battery and the engine are tested. 6. The modular power unit for a work machine of claim 1, wherein the heat exchanger foldably connected to the engine can be folded in a vertical direction to allow access to the battery and the engine. 7. The modular power unit for a work machine of claim 1, wherein the battery and the engine can be separately removed apart from the modular power unit. 8. A work machine, comprising:a chassis;an engine compartment supported by the chassis;an engine mounted on the chassis and within the engine compartment;a generator connected to the engine and mounted within the engine compartment;a battery connected to the engine, and mounted within the engine compartment, but not connected to the generator; anda heat exchanger foldably connected to the engine, the engine, generator, battery and heat exchanger forming a modular power unit that is removable and replaceable from the engine compartment as a single unit without removing any other modules or parts of the work machine. 9. The work machine of claim 8, wherein the heat exchanger is positioned directly over the battery and the engine. 10. The work machine of claim 8, wherein the modular power unit is not integrated with the work machine. 11. The work machine of claim 10, wherein the modular power unit is removable from one work machine and installable in another work machine. 12. The work machine of claim 9, wherein the heat exchanger is removed from the modular power unit when the battery and engine are being serviced. 13. The work machine of claim 9, wherein the heat exchanger can be folded in a vertical direction to allow access to the battery and the engine. 14. Amethod of operating a plurality of machines with a plurality of modular power units, comprising:providing a plurality of work machines;providing a plurality of modular power units, each power unit including an engine, a generator, a battery and heat exchanger, each modular power unit being mounted in an engine compartment of one of the work machines;removing the modular power unit from the engine compartment of the work machine without removing any other modules, parts or systems of the work machine;installing the modular power unit in another engine compartment of another of the plurality of work machines without removing any other modules, parts, or systems of the work machine.
047298650	claims	1. A magnetic fusion reactor comprising, a hollow metallic wave guide, closed upon itself, having a rectangular cross section and containing an electromagnetically resonating, pulsating, self-bombarding plasma in a vacuum, a plurality of equally spaced probes extending to the inner surface of said wave guide and producing a type of transverse electromagnetic coupling with said resonating plasma, with said plasma acting as an internal coaxial cable, said wave guide being vertically positioned between two extended opposite-hand electromagnets which are closed upon themselves and having horseshoe-type cross sections with horizontally oriented bases, and with their internal openings having tear-shaped cross sections containing longitudinal superconducting winding means and coming to a central point such that oppositely-directed magnetic fields are produced vertically in close proximity throughout the entire extent of said wave guide, upwardly directed through one side of said wave guide and downwardly directed through the opposite side, a plurality of equally spaced, ferromagnetic by-pass vanes extending from the vertically oriented surfaces on each side of said opposite-hand electromagnetics, said vanes sloping outward and upward or downward respectively and being spaced to pass equidistantly between opposite-hand components, said vanes curving inward past the vertical midpoint of said wave guide and terminating with their end surfaces parallel to the vertical surfaces of said wave guide, and thus producing narrow, concentrated, curving magnetic fields interspaced with much wider, weaker thicknesses of said oppositely-directed vertical magnetic fields across each corner of the cross section of said rectangular wave guide throughout its entire extent. said pulsating ionic wave continuously incorporating oscillating ions of various types while causing said ions to develop commensurate intersection angles with the boundary between said oppositely-directed magnetic fields, said ions being introduced by any and all means, while also continuously reincorporating each type of said oscillating ions into two oppositely phased, resonating, beta-1 density groups counter to the effects of coulomb scattering, said pulsating ionic wave continuously adjusting the intersection angles of said oscillating ions with the boundary between said oppositely-directed magnetic fields, thereby automatically adjusting itself to the length of said wave guide, said pulsating ionic wave incorporating oscillating ions having intersection angles with the boundary between said oppositely-directed magnetic fields of less than 90.degree., thereby increasing the pulsating plasma self-field, thus increasing the stability of said pulsating ionic wave and improving the plasma containment, said pulsating ionic wave causing said oscillating ions to enter said narrow, curving magnetic fields in such a manner that the horizontal components of said curving magnetic fields convert the vertical velocities of said ions into horizontal velocities and back again, but with the vertical components of said curving magnetic fields causing said oscillating ions to continuously teeter slightly out of phase in both directions with said horizontally pulsating ionic wave, thereby creating a continuous damping of the vertical velocities of said ions as said pulsating ionic wave attempts to reincorporate them back into phase, said electrons being correlated into powerful, constantly changing, horizontally oriented, microwave-sustaining patterns and thereby serving to damp their own vertical oscillations, and to contain themselves within their own electrostatic field, while also producing a reduced plasma pressure and syncrotron radiation of a corresponding lower power density, said electrons being correlated into powerful microwave-sustaining patterns and locally concentrating and dispersing said oppositely-directed magnetic fields, causing said oscillating ions to jiggle at high frequencies and creating a circulating flow of energy from said electrons to said oscillating ions and back again due to ionic collisions, thereby producing a reduced electron temperature with lowered radiation energy losses and higher article densities, said electrons producing a transformer effect whereby said oscillating ions are caused to contribute to an induced flow of said electrons at the plasma outer pulsation node as functions of their individual charges, velocities, and intersection angles with the boundary between said oppositely-directed magnetic fields, and to receive slightly-more-average electron inductances as the plasma proceeds to its inner pulsation node, thereby rapidly reducing each of the said oscillating ions to the vicinity of the mean energy level of that type of ion, including newly introduced replacement ions and positive charged suprathermal particles as they become incorporated into the plasma pulsations, said electrons producing lateral electric potentials at the plasma inner pulsation node, causing said narrow, beta-1 groups of resonating plasma ions to periodically widen rapidly and then to reconverge more slowly due to their outwardly-increasing self-fields in a type of bellows action which produces a further reduction in the plasma electron temperature. 2. The magnetic fusion reactor of claim 1 including means for tangentially injecting ions of a specific energy level in an initial start-up procedure, to oscillate in circular arc lengths at a specific resonance frequency when the injected ions are caused by said oppositely-directed magnetic fields of a specific strength to intersect the boundary between said magnetic fields at some specific intersection angle, with the effective length of said wave guide being equal to an odd number of half-wavelengths of said resonance frequency, wherein said injected ions are caused to spontaneously arrange themselves into two narrow, oppositely-phased groups, constituting a horizontally pulsating, resonating, self-bombarding wave, producing pulsating, outwardly-increasing self-fields and propagating along said wave guide with a free space phase velocity, said pulsating ionic wave creating large numbers of head-on, fusion-producing collisions between said oscillating ions at the plasma inner pulsation node with the planes-of-action of the fusion events being roughly horizontal, thus causing positive charged suprathermal particles to be contained within said wave guide and directing high energy neutrons into appropriately positioned lithium blankets with limited neutron damage. 3. The magnetic fusion reactor of claim 2 including means for introducing electrons along the boundary between said oppositely-directed magnetic fields, wherein pulsating changes in background charge density and massive inductances produced by said pulsating, resonating ionic wave created by tangentially injected ions cause said electrons to arrange themselves into systems of parallel charges pulsating at electron cyclotron frequencies, producing extremely powerful microwave patterns which propagate within said pulsating ionic wave and within said metallic wave guide as high frequency harmonics of the plasma pulsation frequency, thereby causing said electrons to ratchet their way rapidly across the magnetic field lines, 4. The magnetic fusion reactor of claim 2 including oscillating means connected to said equally spaced probes, wherein said pulsating, resonating ionic wave created by tangentially injected ions is caused to produce an alternating voltage in said oscillating means, causing said oscillating means to respond with a powerful, more conventional type of resonating, unidirectional, transverse electromagnetic wave within said wave guide, thereby causing said plasma to obtain such particle energy levels and densities as are required to cause said ions to undergo nuclear fusion reactions, said transverse electromagnetic wave produced by said oscillating means removing energy from said pulsating plasma after such nuclear fusion reactions have been obtained, thereby causing said plasma to operate with optimal particle energy levels in obtaining the highest possible power density for any desired type of fusion reaction.
	abstract	There are provided a high-permittivity dielectric raw material, an antenna device using the raw material and being useful as, especially, the built-in antenna device of a portable phone; a portable phone which can be reduced in weight, thickness and size, with an antenna radiation efficiency improved, and an electromagnetic wave shielding body for effectively shielding electromagnetic wave from an electric cooker.
055457983	abstract	A practical method is described for preparation of radioactive ion-exchange resin for its disposal after the ion-exchange resin has become radioactive in the process of decontaminating radioactive water. Substantially nonradioactive material, which has been derived from the radioactive ion-exchange resin can be disposed of conventionally. The concentration allows corollary reduction of the volume of radioactive waste which must be handled in very costly ways. The radioactive ion-exchange resin and materials that react with the radioactive decaying atoms are heated under controlled atmospheres to (i) form nonvolatile chemicals that hold the decaying atoms, and (ii) under controlled conditions, depolymerize, vaporize, pyrolize, and otherwise decompose and remove nonradioactive components of the ion-exchange resin from the radioactive decaying atoms.
	abstract	One embodiment provides a multi-segment rod that includes a plurality of rod segments. The rod segments are removably mated to each other via mating structures in an axial direction. An irradiation target is disposed within at least one of the rod segments, and at least a portion of at least one mating structure includes one and/or more combinations of neutron absorbing materials.
	claims	1. A system for x-ray mapping, comprising:an ion beam focusing column;an electron focusing column for focusing an electron beam into a sufficiently small spot to resolve material separated by 15 nm;an x-ray optic for receiving x-rays emitted from the sample, the x-ray optic receiving and transmitting x-rays impinging on the optic entrance at angles up to at least 10 degrees; andmultiple x-ray detectors, each x-ray detector including:an absorber for absorbing x-rays exiting the x-ray optic; anda temperature sensing device for converting a change in temperature of the x-ray absorber into an electronic signal, the multiple x-ray detectors capable of resolving energy difference of 15 eV,the system capable of determining a material map composed of 100 pixels by 100 pixels while collecting x-rays for a period of less than twenty minutes. 2. The system of claim 1 in which the x-ray optic receives and transmits x-rays impinging on the optic entrance at angles up to at least 15 degrees. 3. The system of claim 1 in which the multiple x-ray detectors comprise at least nine x-ray detectors. 4. The system of claim 1 in which the x-ray optic comprises a bundle of capillaries. 5. The system of claim 1 in which the temperature sensing device includes a neutron transmutation doped germanium semiconductor. 6. The system of claim 1 further comprising one or more computers for controlling the system, the computers including memory computer storing a program for directing the ion beam focusing column to remove a layer of material from a portion of the sample, scanning the electron beam over at least a part of the portion of the sample, and recording the material present at different locations on multiple layers of the sample, the material being determined by information from the x-ray detectors. 7. The system of claim 1 in which the system is characterized by a figure of merit of greater than 500 nC−1 for the Mg K line of bulk Mg containing a native oxide irradiated by 5 keV electrons. 8. The system of claim 1 in which the system is capable of producing a signal to noise ratio of less than 4 for the Au M line emitted from bulk Au irradiated by 5 keV electrons. 9. A method of forming a high spatial resolution, high energy resolution x-ray map of a sample, comprising:a. directing a beam of electrons having energies of less than 5,000 eV toward a sample in a vacuum chamber, the electron beam forming a spot having a diameter of less than 50 nm on the sample;b. conducting x-rays created by the impact of the electrons on the sample through an x-ray optic towards multiple cryogenic x-ray detectors;c. determining the energy of the x-rays impacting the detector to determine the material present at the location at which the electron beam impacts the sample;d. moving the impact point of the electron beam to a different point on the surface and repeating steps b and c for an array of at least 5,000 points in a time period of less than one hour to produce a map of material present in the region scanned by the electron beam. 10. The method of claim 9 further comprising removing a layer of material including the points to which the electron beam was directed and repeating steps a-d for a second array of points below the first array of points to produce a three-dimensional x-ray map. 11. The method of claim 10 in which removing a layer of material includes directing a focused ion beam toward the sample to remove the layer of material without removing the sample from the vacuum chamber. 12. The method of claim 9 in which conducting x-rays created by the impact of the electrons on the sample through an x-ray optic towards multiple cryogenic x-ray detectors includes conducting x-rays using a bundle of capillaries, the bundle having an acceptance angle of greater than 10 degrees. 13. The method of claim 9 in which determining the energy of the x-rays impacting the detector includes measuring the increase in temperature of an x-ray absorber using a neutron transmutation doped germanium crystal. 14. The method of claim 9 in which moving the impact point of the electron beam to a different point on the surface and repeating steps b and c includes moving the impact point of the electron beam to an array of at least 10,000 points in a time period of less than one half hour to produce a map of material present in the region scanned by the electron beam. 15. The method of claim 9 conducting x-rays created by the impact of the electrons on the sample through an x-ray optic towards multiple cryogenic x-ray detectors includes focusing the x-rays onto multiple detectors. 16. The method of claim 9 conducting x-rays created by the impact of the electrons on the sample through an x-ray optic towards multiple cryogenic x-ray detectors includes defocusing the x-rays to spread them over multiple detectors. 17. A system for x-ray mapping of a sample to show the material present at different positions on the sample, comprising:an electron focusing column capable of focusing an electron beam to a sufficiently small beam spot to resolve material separated by 15 nm;an x-ray optic for receiving x-rays emitted from the sample, the entrance to the x-ray optic receiving x-rays over a solid angle of at least 10 degrees; andmultiple x-ray detectors, each x-ray detector including:an absorber for absorbing x-rays exiting the x-ray optic; anda temperature sensing device for converting a change in temperature of the x-ray absorber into an electronic signal, the multiple x-ray detectors are capable of resolving energy difference of 15 eV,the system capable of determining a material map composed of 100 by 100 pixels while collecting x-rays for a period of less than twenty minutes. 18. The system of claim 17 in which the multiple x-ray detectors comprise at least nine x-ray detectors. 19. The system of claim 17 in which the temperature sensing device includes a neutron transmutation doped germanium semiconductor. 20. The system of claim 17 further comprising one or more computers for controlling the system, the computers including memory computer storing a program for directing the ion beam focusing column to remove a layer of material from a portion of the sample, scanning the electron beam over at least a part of the portion of the sample, and recording the material present at different locations on multiple layers of the sample, the material being determined by information from the x-ray detectors. 21. The system of claim 17 in which the system is characterized by a figure of merit of greater than 1000 nC−1 for the Au M line emitted from bulk Au irradiated by 5 keV electrons.
	claims	1. A modified metal-organic-framework material, comprising:a waste material adsorbed in the metal-organic framework material having a crystalline porous structure;wherein the crystalline porous structure of the metal-organic framework material has been converted to an amorphous structure. 2. The material of claim 1, wherein the metal-organic framework material is selected from a group consisting of carboxylate-based MOFs, phosphonate-based MOFs, N-based linker MOFs, and N—O-heterofunctional linkers based MOFs. 3. The material of claim 1, wherein the metal-organic framework material is selected from a group consisting of IRMOFs series, MOF-74 series, Sandia Metal-Organic Frameworks (SMOFs) series, and ZIFs series. 4. The material of claim 1, wherein the waste material is a gas. 5. The material of claim 1, further comprising an ionic species adsorbed from solution. 6. The material of claim 4, wherein the gas is selected from the group consisting of isotope form of I, H, CO, CO2, Kr, Xe, Ra, Cs, Ba, Y, Sr, and Rb. 7. The material of claim 5, wherein the ionic species is selected from the group consisting of cesium and radioactive uranyl-containing ions. 8. The material of claim 1, wherein the metal-organic framework material is treated with an additive before adsorbing the waste material. 9. The material of claim 8, wherein the additive is silver or palladium. 10. A method of forming a waste storage material, comprising:providing a metal-organic framework material having a crystalline structure;adsorbing a waste material into pores of the metal-organic framework material; andapplying pressure to the metal-organic framework material to convert the crystalline structure of the metal-organic framework to an amorphous structure. 11. The method of claim 10, wherein the pressure is between 7,350 psi and 18,000 psi. 12. The method of claim 8, wherein the pressure is applied at ambient temperature. 13. The method of claim 8, wherein the metal-organic framework material is first treated by impregnating the metal-organic framework material with silver. 14. The method of claim 10, wherein pressure is applied by hot isostatic pressing at a temperature below the volitization temperature of the waste.
	description	This application claims priority to U.S. Provisional Application Ser. No. 60/806,204 entitled “Methods and Systems for Providing Illumination of a Specimen for Inspection,” filed Jun. 29, 2006, which is incorporated by reference as if fully set forth herein. 1. Field of the Invention The present invention generally relates to methods and systems for providing illumination of a specimen for a process performed on the specimen. Certain embodiments relate to methods and systems for providing illumination of a specimen using an electrodeless lamp. 2. Description of the Related Art The following description and examples are not admitted to be prior art by virtue of their inclusion in this section. Fabricating semiconductor devices such as logic and memory devices typically includes processing a substrate such as a semiconductor wafer using a large number of semiconductor fabrication processes to form various features and multiple levels of the semiconductor devices. For example, lithography is a semiconductor fabrication process that involves transferring a pattern from a reticle to a resist arranged on a semiconductor wafer. Additional examples of semiconductor fabrication processes include, but are not limited to, chemical-mechanical polishing, etch, deposition, and ion implantation. Multiple semiconductor devices may be fabricated in an arrangement on a single semiconductor wafer and then separated into individual semiconductor devices. Inspection processes are used at various steps during a semiconductor manufacturing process to detect defects on wafers to promote higher yield in the manufacturing process and thus higher profits. When inspecting specular or quasi-specular surfaces such as semiconductor wafers, bright field (BF) and dark field (DF) modalities are used. In BF inspection systems, collection optics are positioned such that the collection optics capture a substantial portion of the light specularly reflected by the surface under inspection. In contrast, in DF inspection systems, the collection optics are positioned out of the path of the specularly reflected light such that the collection optics capture light scattered by objects on the surface being inspected such as microcircuit patterns or contaminants on the surfaces of wafers. Many different light sources have been used in inspection systems. For example, electrode based, relatively high intensity discharge arc lamps are used in inspection systems. However, these light sources have a number of disadvantages, For instance, electrode based, relatively high intensity discharge arc lamps have brightness limits and power limits due to electrostatic constraints on current density from the electrodes, the limited emissivity of gases as black body emitters, the relatively rapid erosion of electrodes made from refractory materials due to the presence of relatively large current densities at the cathodes, and the inability to control dopants (which can lower the operating temperature of the refractory cathodes) for relatively long periods of time at the required emission current. Many different light sources have also been developed for various other applications. For instance, some carbon dioxide laser produced plasma lamps have been developed though not disclosed for use in wafer or reticle inspection applications. Examples of such plasma lamps are described in Smith, Appl. Phys. Lett., 19(10), 405-408 (1971), Cohn et al., Appl. Phys. Lett., 20(6), 225-227 (1972), Franzen, Appl. Phys. Lett., 21(2), 62-64 (1972), and Harilal et al., Appl. Phys. Lett., 72(2), 167-169 (1998), which are incorporated by reference as if fully set forth herein. Accordingly, it may be advantageous to develop electrodeless lamps for inspection applications, for example, by optimizing the operation of deep ultraviolet (DUV) electrodeless lamps for use in inspection applications such as semiconductor wafer inspection by optimizing the pressure, gas type, energy deposition, energy deposition profile, or some combination thereof of the lamp while at the same time eliminating the need for electrodes. The following description of various embodiments of methods and systems is not to be construed in any way as limiting the subject matter of the appended claims. One embodiment relates to a system configured to provide illumination of a specimen for a process performed on the specimen. The system includes a laser configured to generate excitation light. The system also includes focusing optics configured to focus the excitation light to a plasma in an electrodeless lamp such that the plasma generates light. The system is also configured such that the light illuminates the specimen during the process. In one embodiment, the laser includes a continuous-wave (cw) laser. In another embodiment, the laser includes a diode laser, a diode laser stack, a fiber laser, a fiber coupled diode laser, a carbon dioxide laser, an acoustically modulated diode, or a diode pumped fiber laser. In one embodiment, a power of the laser is greater than about 100 W. In an additional embodiment, an optical average cw power of the excitation light is about 100 W to about 1000 W. In a further embodiment, the system includes an additional laser configured to generate additional excitation light. In one such embodiment, the focusing optics are configured to focus the additional excitation light to the plasma, and a sum of the power of the laser and the additional laser is in a range of about 100 W cw to about 1000 W cw. In one embodiment, a wavelength of the excitation light is about 0.7 μm to about 1.5 μm. In another embodiment, a wavelength of the excitation light is less than about 10 μm. In one embodiment, the focusing optics are configured to focus the excitation light to the lamp to initiate the plasma. In another embodiment, the system includes a pulsed light source, a radio frequency coil, a voltage source external to the lamp, or some combination thereof configured to initiate the plasma. In one embodiment, the plasma has a geometry shaped to substantially match collection optics of a detection subsystem of a system configured to inspect the specimen. In another embodiment, an excitation volume of the electrodeless lamp is substantially matched to a field of view of collection optics of a detection subsystem of a system configured to inspect the specimen. In an additional embodiment, the plasma has a cylindrical shape substantially matched to image onto the specimen in the system. In one embodiment, the focusing optics are configured to focus the excitation light to a cylindrical-shaped region within the electrodeless lamp. In one such embodiment, the cylindrical-shaped region has a diameter of about 0.5 mm to about 1 mm and a thickness of about 100 μm to about 200 μm. In another embodiment, the system includes at least one additional laser configured to generate additional excitation light. In one such embodiment, the focusing optics are configured to direct the excitation light and the additional excitation light to the plasma simultaneously such that the excitation light and the additional excitation light overlap within a cylindrical-shaped region within the electrodeless lamp, and the cylindrical-shaped region has a diameter of about 0.5 mm to about 1 mm and a thickness of about 100 μm to about 200 μm. In one embodiment, the laser includes a frequency doubled laser, and a wavelength of the excitation light is about 0.4 μm to about 0.7 μm. In one embodiment, the light generated by the plasma includes deep ultraviolet (DUV) light. In another embodiment, the light generated by the plasma includes broadband light. In a further embodiment, the light generated by the plasma has a single line spectra. In one embodiment, the light generated by the plasma includes light in a spectral region from about 180 nm to about 450 nm. In another embodiment, the light generated by the plasma includes light in a spectral region from about 200 nm to about 450 nm. In an additional embodiment, the plasma is generated using a rare earth gas and a mercury gas, and the light generated by the plasma includes light in a spectral region from about 230 nm to about 480 nm. In one embodiment, the light generated by the plasma includes excimer radiation, and the electrodeless lamp includes about 1 atm or more of background rare gas and about 1 atm or less of a halide containing gas. In one embodiment, the plasma has a diameter of about 0.5 mm to about 1 mm. In another embodiment, the light generated by the plasma has a diameter of about 100 μm to about 2 mm. In one embodiment, the electrodeless lamp is at a pressure of above about 1 atm at a working temperature of the electrodeless lamp, and the light generated by the plasma includes light in a spectral region from about 200 nm to about 400 nm. In some embodiments, the light generated by the plasma has a brightness of about 10 W/mm2-sr to about 50 W/mm2-sr in a spectral region from about 200 nm to about 400 nm. In another embodiment, the light generated by the plasma has a brightness of about 2 W/mm2-sr to about 50 W/mm2-sr in an integral region of the electromagnetic spectrum from about 200 nm to about 400 nm. In a further embodiment, the light generated by the plasma has an average power of at least about 3 W within any band in a spectral region from about 200 nm to about 450 nm. In one embodiment, a temperature of the plasma is about 10,000 K to about 30,000 K. In another embodiment, a temperature of the plasma is held substantially constant by the excitation light. In some embodiments, the electrodeless lamp includes a fill gas, and the fill gas includes argon, krypton, xenon, fluorine, chlorine, chlorine dimers, fluorine dimers, a homogenous diatomic gas, nitrogen trifluoride, sulfur hexafluoride, nitric oxide, mercury, a halide containing gas, mercury halides, diatomic halides, halides, a rare gas, rare earths, transition metals, lanthanide metals, or some combination thereof. In one embodiment, the electrodeless lamp includes a fill gas at a gas pressure such that an opacity of the plasma does not prohibit a majority of the light generated by the plasma from exiting the lamp. In another embodiment, the plasma does not produce an average plasma opacity over a plasma axis length of greater than about 1 e-folding from one end of the electrodeless lamp to another end of the electrodeless lamp. In an additional embodiment, the electrodeless lamp includes a fill gas, and an opacity of the fill gas at a working temperature and pressure of the electrodeless lamp is less than or equal to about 10% reabsorption of light emitted from a center of the lamp within a spectral region from about 200 nm to about 450 nm. In one embodiment, a fill pressure of gases in the electrodeless lamp is about 4 atm or higher. In another embodiment, a fill pressure of the electrodeless lamp is about 5 atm to about 20 atm at room temperature. In a further embodiment, a gas pressure within the electrodeless lamp is about 1 atm to about 50 atm. In one embodiment, the plasma includes one or more species that fluoresce in a region between about 180 nm and about 350 nm to a ground electronic state. In one such embodiment, the one or more species include mercury that emits resonance lines at 2537 Å, neutral barium that emits resonance lines at 2409 Å, neutral cobalt that emits resonance lines at 2402 Å, neutral magnesium that emits resonance lines at 2025 Å, neutral nickel that emits resonance lines at 2026 Å, neutral scandium that emits resonance lines at 2000 Å, neutral nickel terminating on a 879 cm−1 electronic metastable state, or some combination thereof. In another such embodiment, atoms or molecules that form the one or more species are present in the electrodeless lamp prior to generation of the plasma in a quantity or quantities that limit the vapor pressure of the atoms or molecules in the electrodeless lamp such that substantially all of the atoms or molecules are vaporized before the lamp reaches operating temperature. In a further such embodiment, the one or more species include atoms formed by decomposition of feed molecules in the electrodeless lamp. In some embodiments, the plasma includes one or more species that fluoresce in a region between about 180 nm and about 350 nm to electronic metastable states within about 0.5 eV of a ground electronic state. In some such embodiments, the one or more species include mercury that emits resonance lines at 2537 Å, neutral barium that emits resonance lines at 2409 Å, neutral cobalt that emits resonance lines at 2402 Å, neutral magnesium that emits resonance lines at 2025 Å, neutral nickel that emits resonance lines at 2026 Å, neutral scandium that emits resonance lines at 2000 Å, neutral nickel terminating on a 879 cm−1 electronic metastable state, or some combination thereof. In another such embodiment, atoms or molecules that form the one or more species are present in the electrodeless lamp prior to generation of the plasma in a quantity or quantities that limit the vapor pressure of the atoms or molecules in the electrodeless lamp such that substantially all of the atoms or molecules are vaporized before the lamp reaches operating temperature. In a further such embodiment, the one or more species include atoms formed by decomposition of feed molecules in the electrodeless lamp. In one embodiment, the electrodeless lamp includes one or more operating gases that have atomic transitions from electronically excited states to a ground electronic state of one or more corresponding neutral atoms or a state within about 1 eV to about 2 eV of the ground electronic state. In another embodiment, the electrodeless lamp includes feed molecules of which about 1% or greater are dissociated at an operating temperature proximate a center of the plasma. In one such embodiment, the feed molecules include iodine, chlorine, bromine, sulfur, nitrogen, oxygen, a diatomic gas, one or more homonuclear diatomic feed materials capable of recombining to form only their corresponding molecular species, one or more rare gases, or some combination thereof. In an additional embodiment, the electrodeless lamp includes feed molecules of which about 1% or greater are dissociated at an operating temperature of about 600 K to about 25,000 K. In one embodiment, the electrodeless lamp includes diatomic hydrogen. In one such embodiment, the light generated by the plasma has a wavelength of about 121 nm. In another such embodiment, the light generated by the plasma has a wavelength of about 121 nm, about 937 nm, about 949 nm, about 972 nm, about 1025 nm, or some combination thereof. In one embodiment, the electrodeless lamp includes a background rare gas and a gas containing a halide. In one such embodiment, a pressure of the background rare gas is at least about 1 atm, and a pressure of the gas containing the halide is less than or equal to about 1 atm. In one embodiment, the electrodeless lamp includes one of an internal lens and a curved reflector. In another embodiment, the focusing optics include a lens configured to focus the excitation light to a spot size and radiance sufficient to sustain the plasma. In one such embodiment, the lens has a numerical aperture (NA) of at least about 0.3. In an additional embodiment, the focusing optics include a lens configured to focus the excitation light to the plasma such that the plasma has a predetermined shape. In one such embodiment, the lens has an NA of at least about 0.3. In one embodiment, the system includes at least one heat source located proximate to the electrodeless lamp and configured to maintain atoms in the plasma in a vapor phase. In one embodiment, the system includes an illumination subsystem configured to illuminate the specimen during the process with the light generated by the plasma. In one such embodiment, the illumination subsystem includes a condenser lens configured to collect the light generated by the plasma. In another such embodiment, the illumination subsystem includes an elliptical reflector configured to collect the light generated by the plasma, and the plasma is located at one focal point of the elliptical reflector. In one embodiment, the specimen includes a wafer. In another embodiment, the specimen includes a patterned wafer. In an additional embodiment, the specimen includes a reticle. In one embodiment, an NA of the focusing optics is selected such that a size of the plasma is reduced along a direction to which the excitation light is focused to the plasma by the focusing optics. In one embodiment, the laser includes a distributed light source. In an additional embodiment, the focusing optics include at least one optical element configured to focus the excitation light to the plasma and configured to collect the light generated by the plasma. In one embodiment, the focusing optics are configured to focus the excitation light to the plasma in two substantially opposite directions simultaneously. In another embodiment, the focusing optics include at least one reflective optical element and at least one refractive optical element, and the at least one reflective optical element and the at least one refractive optical element are configured to focus the excitation light to the plasma simultaneously. In an additional embodiment, the focusing optics are configured to focus the excitation light to the plasma in two substantially perpendicular directions. In one embodiment, the focusing optics are configured to focus the excitation light to the plasma at different directions simultaneously to substantially the same focal spot. In another embodiment, the focusing optics are configured to focus the excitation light to the plasma at different directions simultaneously to offset focal spots. In a further embodiment, the focusing optics are configured to collect the excitation light that is not absorbed by the plasma and to focus the collected excitation light to the plasma. In one embodiment, the system includes a gas flow subsystem configured to direct a gas to the plasma such that the gas directed to the plasma affects a shape of the plasma. In another embodiment, the system includes a gas flow subsystem configured to direct a gas to the plasma such that the gas directed to the plasma increases isolation of the plasma. In an additional embodiment, the system includes a gas flow subsystem configured to direct a gas to the plasma at a direction substantially opposite to a direction at which the focusing optics focus the excitation light to the plasma. In a further embodiment, the system includes a gas flow subsystem configured to direct a gas to the plasma at a direction substantially perpendicular to a direction at which the focusing optics focus the excitation light to the plasma. In some embodiments, the system includes a gas flow subsystem configured to direct a gas to the plasma such that the gas increases propagation of the generated light through the plasma. In one embodiment, the system includes a gas flow subsystem configured to direct a gas to the plasma through an aperture in an optical element of the focusing optics. In another embodiment, the system includes a gas flow subsystem configured to direct a gas to the plasma through a sonic or supersonic nozzle to reduce a volume of the plasma and to reduce absorption of the generated light by the gas. In some embodiments, the system includes a gas flow subsystem configured to direct a gas to the plasma. In one such embodiment, the gas flow subsystem includes a cylindrical-shaped nozzle. In another such embodiment, the gas directed to the plasma increases uniformity of a density profile of the plasma. In an additional such embodiment, the gas directed to the plasma creates an interaction media having a density suitable for interactions between the excitation light and the plasma. In a further such embodiment, a pressure of the gas directed to the plasma is selected based on one or more predetermined characteristics of the plasma. In yet another such embodiment, the gas flow subsystem includes a nozzle through which the gas is directed to the plasma, and a diameter of the nozzle is selected based on one or more predetermined characteristics of the plasma. In some embodiments, the system includes a gas flow subsystem configured to direct a gas jet to the plasma. In one such embodiment, the focusing optics are configured to direct the excitation light to one or more edges of the gas jet thereby affecting a shape of the gas jet. In one embodiment, the system is configured to apply an external magnetic field to the plasma to alter one or more characteristics of the plasma. In another embodiment, the system includes a gas flow subsystem configured to direct one or more feed materials to the plasma after generation of the plasma. In an additional embodiment, the system includes a cleaning subsystem configured to remove photocontamination from one or more optical elements of the focusing optics, one or more optical elements of the system, or some combination thereof. In some embodiments, the plasma is generated from one or more feed materials that include a liquid. In one embodiment, the system includes an illumination subsystem configured to illuminate the specimen during the process with the light generated by the plasma, and the illumination subsystem includes a reflective optical element configured to collect the light generated by the plasma and to direct the collected light to one or more refractive optical elements of the illumination subsystem. In another embodiment, the focusing optics include a reflective optical element configured to focus the excitation light to the plasma, and the excitation light includes an expanded laser beam. In an additional embodiment, the focusing optics are configured to focus the excitation light to the plasma at different directions simultaneously. In a further embodiment, the system includes an illumination subsystem configured to illuminate the specimen during the process with the light generated by the plasma, and the illumination subsystem includes one or more refractive optical elements configured to focus the excitation light to the plasma. In some embodiments, the focusing optics include at least one optical element configured to focus the excitation light to the plasma and configured to collect the light generated by the plasma, and the at least one optical element includes a reflective optical element. In one embodiment, the system includes an illumination subsystem configured to illuminate the specimen during the process with the light generated by the plasma. In one such embodiment, the illumination subsystem is configured to collect the light generated by the plasma across a solid angle of about 4π. In another such embodiment, the illumination subsystem is configured to direct the light to a pupil plane of the system such that the light has a substantially uniform intensity across the pupil plane. In an additional such embodiment, the illumination subsystem includes a partial elliptical reflector and a half spherical reflector. In one such embodiment, the plasma is positioned at one focal point of the partial elliptical reflector, and the half spherical reflector is substantially centered to the plasma. In another such embodiment, the partial elliptical reflector and the half spherical reflector are configured to collect the light generated by the plasma, the half spherical reflector is configured to direct the light collected by the half spherical reflector to the partial elliptical reflector, and the partial elliptical reflector is configured to direct the light from the half spherical reflector and the light collected by the partial elliptical reflector to another optical element of the illumination subsystem. Each of the embodiments of the system described above may be further configured as described herein. In addition, each of the embodiments of the system described above may be included in any of the other systems described herein and may be used in any of the methods described herein. Another embodiment relates to a method for providing illumination of a specimen for a process performed on the specimen. The method includes focusing excitation light from a laser to an electrodeless lamp to generate a plasma in the electrodeless lamp such that the plasma generates light. The method also includes illuminating the specimen with the generated light during the process. The embodiment of the method described above may include any other step(s) of any other method(s) described herein. In addition, the embodiment of the method described above may be performed by any of the systems described herein. An additional embodiment relates to a method for determining one or more characteristics of a specimen. The method includes focusing excitation light from a laser to an electrodeless lamp to generate a plasma in the electrodeless lamp such that the plasma generates light. The method also includes illuminating the specimen with the generated light. In addition, the method includes generating output responsive to light from the specimen resulting from the illumination of the specimen. The method further includes determining the one or more characteristics of the specimen using the output. The embodiment of the method described above may include any other step(s) of any other method(s) described herein. In addition, the embodiment of the method described above may be performed by any of the systems described herein. A further embodiment relates to a system configured to determine one or more characteristics of a specimen. The system includes a laser configured to generate excitation light. The system also includes focusing optics configured to focus the excitation light to a plasma in an electrodeless lamp such that the plasma generates light. In addition, the system includes an illumination subsystem configured to illuminate the specimen with the light generated by the plasma. The system further includes a detection subsystem configured to generate output responsive to light from the specimen due to illumination of the specimen. The output can be used to determine the one or more characteristics of the specimen. In one embodiment, the system is configured as a bright field inspection system. In another embodiment, the system is configured as a dark field inspection system. In an additional embodiment, the system is configured as a defect review system. In a further embodiment, the system is configured as a metrology system. In one embodiment, the one or more characteristics include one or more dimensions of one or more patterned features formed on the specimen. In another embodiment, the one or more characteristics include a shape of one or more patterned features formed on the specimen. In one embodiment, the specimen includes a wafer. In another embodiment, the specimen includes a patterned wafer. In an additional embodiment, the specimen includes a reticle. Each of the embodiments of the system described above may be further configured as described herein. In addition, each of the embodiments of the system described above may be used in any of the methods described herein. Yet another embodiment relates to a system configured to generate an image of a specimen. The system includes a laser configured to generate excitation light. The system also includes focusing optics configured to focus the excitation light to a plasma in an electrodeless lamp such that the plasma generates light. In addition, the system includes an illumination subsystem configured to illuminate the specimen with the light generated by the plasma. The system further includes a detection subsystem configured to generate output responsive to electrons emitted by the specimen due to illumination of the specimen with the light generated by the plasma. The output includes the image of the specimen. In one embodiment, the light generated by the plasma includes DUV light. In another embodiment, the specimen includes a surface formed of a semiconductive material. In an additional embodiment, the light generated by the plasma includes broadband light such that the system can image a selectable set of work functions of the specimen. Each of the embodiments of the system described above may be further configured as described herein. In addition, each of the embodiments of the system described above may be used in any of the methods described herein. Still another embodiment relates to a system configured to perform a lithography process on a specimen. The system includes a laser configured to generate excitation light. The system also includes focusing optics configured to focus the excitation light to a plasma in an electrodeless lamp such that the plasma generates light. In addition, the system includes an illumination subsystem configured to image the light generated by the plasma onto the specimen in a predetermined pattern such that the predetermined pattern can be transferred to the specimen. In one embodiment, the light generated by the plasma includes i-line light. Each of the embodiments of the system described above may be further configured as described herein. In addition, each of the embodiments of the system described above may be used in any of the methods described herein. As used herein, the term “specimen” generally refers to a wafer, a photomask, or a reticle. However, it is to be understood that the methods and systems described herein may be used for providing illumination of any other specimen known in the art and/or determining one or more characteristics (e.g., by inspection, defect review, metrology, imaging, etc.) of any other specimen known in the art. As used herein, the term “wafer” generally refers to substrates formed of a semiconductor or non-semiconductor material. Examples of such a semiconductor or non-semiconductor material include, but are not limited to, monocrystalline silicon, gallium arsenide, and indium phosphide. Such substrates may be commonly found and/or processed in semiconductor fabrication facilities. A wafer may include one or more layers formed upon a substrate. For example, such layers may include, but are not limited to, a resist, a dielectric material, a semiconductive material, and a conductive material. Many different types of such layers are known in the art, and the term wafer as used herein is intended to encompass a wafer including all types of such layers. One or more layers formed on a wafer may be patterned. For example, a wafer may include a plurality of dies, each having repeatable patterned features. Formation and processing of such layers of material may ultimately result in completed devices. Many different types of devices may be formed on a wafer, and the term wafer as used herein is intended to encompass a wafer on which any type of device known in the art is being fabricated. The terms “reticle” and “photomask” are used interchangeably herein. A reticle generally includes a transparent substrate such as glass, borosilicate glass, and fused silica having opaque regions formed thereon. The opaque regions may be replaced by regions etched into the transparent substrate. Many different types of reticles are known in the art, and the term reticle as used herein is intended to encompass all types of reticles. Turning now to the drawings, it is noted that the figures are not drawn to scale. In particular, the scale of some of the elements of the figures is greatly exaggerated to emphasize characteristics of the elements. It is also noted that the figures are not drawn to the same scale. Elements shown in more than one figure that may be similarly configured have been indicated using the same reference numerals. FIG. 1 illustrates one embodiment of a system configured to determine one or more characteristics of a specimen. For example, the system shown in FIG. 1 is configured to inspect a specimen. In some embodiments, the system is configured as a bright field (BF) inspection system. In this manner, the system may be configured for BF inspection of the specimen. In addition, or alternatively, the system may be configured as a dark field (DF) inspection system. As such, the system may be configured for DF inspection of the specimen. For example, the system shown in FIG. 1 may include a BF channel and a DF channel. However, the inspection system may include a BF channel or a DF channel. The BF channel and the DF channel are configured to generate inspection output and/or other output for the specimen. It is noted that FIG. 1 is provided herein to generally illustrate one embodiment of a configuration for the system. Obviously, the system configuration described herein may be altered to optimize the performance of the system as is normally performed when designing a commercial inspection or other measurement system. In addition, the systems described herein may be implemented using an existing inspection or other measurement system (e.g., by adding one or more light sources described herein to an existing inspection system or replacing one or more light sources of an existing inspection system with one or more light sources described herein). Alternatively, the system described herein may be designed “from scratch” to provide a completely new system. The system shown in FIG. 1 includes light source 10 (i.e., an illumination source). Light source 10 may be configured according to any of the embodiments described herein. In particular, light source 10 is an electrodeless lamp configured to generate light. More specifically, the electrodeless lamp includes a plasma (not shown in FIG. 1) that generates light. In addition, as described further herein, the system includes a laser (not shown in FIG. 1) configured to generate excitation light and focusing optics (not shown in FIG. 1) configured to focus the excitation light to the plasma in the electrodeless lamp such that the plasma generates light. The laser, the focusing optics, the plasma, and the electrodeless lamp may be further configured according to any of the embodiments described herein. The system may also include two or more light sources (not shown). The two or more light sources may be configured similarly or differently. For example, the light sources may be configured to generate light having different characteristics (e.g., wavelength, polarization, etc.) that can be directed to a specimen at the same or different angles of incidence and at the same or different time. The two or more light sources may be configured according to any of the embodiments described herein. In addition, one of the light sources may be configured according to any of the embodiments described herein, and another light source included in the system may include any other light source known in the art (e.g., a laser). The system also includes an illumination subsystem configured to illuminate the specimen with the light generated by the plasma. For example, the illumination subsystem may include one or more optical elements configured to direct the light to the specimen. In one such example, the one or more optical elements may include beam splitter 12 and objective 14. Beam splitter 12 is configured to direct light from light source 10 to objective 14. Objective 14 is configured to focus the light from beam splitter 12 onto specimen 16 at a substantially normal angle of incidence. However, the system may be configured to direct the light to the specimen at any suitable angle of incidence. Beam splitter 12 may include any appropriate optical component known in the art. Objective 14 may include any appropriate refractive optical component known in the art. In addition, although objective 14 is shown in FIG. 1 as a single refractive optical component, objective 14 may include one or more refractive optical components and/or one or more reflective optical components. In one embodiment, the specimen includes a wafer. In another embodiment, the specimen includes a patterned wafer. In an additional embodiment, the specimen includes a reticle. Therefore, the system may be configured for inspection of a wafer, a patterned wafer, and a reticle. The specimen may be further configured as described herein. The system also includes a detection subsystem configured to generate output responsive to light from the specimen due to illumination of the specimen. The detection subsystem may include multiple, independent detection channels. Each detection channel is configured to collect light scattered or reflected from the specimen under test over a unique set of collection angles. In addition, although embodiments are described further herein as including a BF channel and a DF channel, the detection subsystem may include any combination of one or more detection channels (e.g., one BF channel and/or one or more DF channels). Moreover, the detection subsystem may include a number of detection channels, and output generated by all of the detection channels or fewer than all of the detection channels may be used by a processor as described further herein. The output generated by a particular combination of detection channels that is used by a processor as described further herein may be selected based on, for example, characteristics of the specimen, characteristics of the defects of interest, and characteristics of the system. In the embodiment shown in FIG. 1, light reflected from specimen 16 is collected by objective 14 and passes through beam splitter 12 to detector 18. Detector 18 may include any appropriate detector known in the art. Detector 18 is configured to generate output for specimen 16. In addition, detector 18 may include an imaging detector. Therefore, the output generated by detector 18 may include image data. As shown in FIG. 1, objective 14 is configured to collect light specularly reflected from the specimen, and detector 18 is configured to detect light specularly reflected from the specimen. Therefore, objective 14 and detector 18 form the BF channel of the system. As such, the BF channel of the system is configured to generate output for the specimen. In addition, the BF channel of the system may be configured to generate output that includes image data. Light scattered from specimen 16 is collected by objective 20, which directs the collected light to detector 22. Objective 20 may include any appropriate refractive optical component known in the art. In addition, although objective 20 is shown in FIG. 1 as a single refractive optical component, objective 20 may include one or more refractive optical components and/or one or more reflective optical components. Objective 20 may be configured to collect light scattered from the specimen at any suitable scattering angles. The scattering angles at which objective 20 is configured to collect light scattered from the specimen may be determined based on one or more characteristics (e.g., of patterned features (not shown) or defects of interest (not shown)) of the specimen. Detector 22 may include any appropriate detector known in the art. Detector 22 is configured to generate output for specimen 16. In addition, detector 22 may include an imaging detector. Therefore, the output generated by detector 22 may include image data. As shown in FIG. 1, objective 20 is configured to collect light scattered from the specimen, and detector 22 is configured to detect light scattered from the specimen. Therefore, objective 20 and detector 22 form the DF channel of the system. As such, the DF channel of the system is configured to generate output for the specimen. In addition, the DF channel of the system may be configured to generate output that includes image data. In some embodiments, the BF channel and the DF channel are configured to generate the output in the deep ultraviolet (DUV) spectrum. For example, as described further herein, light source 10 may be configured to generate light in the DUV spectrum. In addition, detectors 18 and 22 may be configured to detect light reflected and scattered, respectively, in the DUV spectrum. However, the BF and DF channels may also or alternatively be configured to generate the output in any other suitable spectrum (e.g., DUV, ultraviolet (UV), visible, vacuum ultraviolet (VUV), or some combination thereof), which may vary depending on, for example, the spectral region in which light source 10 generates light. During generation of the output by the BF and DF channels of the system, specimen 16 may be disposed on stage 24. Stage 24 may include any appropriate mechanical and/or robotic assembly known in the art (e.g., a scanning stage configured to support the specimen under test). The system may also include processor 26. Processor 26 may be coupled to detectors 18 and 22 such that the processor can receive output from detectors 18 and 22. Processor 26 may be coupled to the detectors in any suitable manner known in the art (e.g., via a transmission medium (not shown) that may include “wired” and/or “wireless” portions, via electronic components (not shown) interposed between each of the detectors and the processor, etc.). The output generated by the detection subsystem (e g., output generated by detectors 18 and/or 22) can be used to determine one or more characteristics of specimen 16. For example, processor 26 may be configured to use the output generated by the detection subsystem to detect defects on the specimen (thereby determining one or more characteristics of the specimen such as whether or not defects are present on the specimen, number of defects on the specimen, locations of defects on the specimen, etc.). The processor may be configured to detect the defects on the specimen and to determine one or more characteristics of the specimen using the output and any appropriate method and/or algorithm known in the art. The processor may also be configured to perform any other step(s) of any other method(s) described herein. Processor 26 may take various forms, including a personal computer system, mainframe computer system, workstation, image computer, parallel processor, or any other device known in the art. In general, the term “computer system” may be broadly defined to encompass any device having one or more processors, which executes instructions from a memory medium. The system shown in FIG. 1 may also include any other suitable components (not shown) known in the art. Furthermore, light sources described herein can be used in a commercially available inspection system such as the 2360, 2365, 2371, 23xx, and 28xx systems that are available from KLA-Tencor, San Jose, Calif. In addition, the electrodeless lamp embodiments described herein may be used in any other appropriate system, some examples of which are illustrated in U.S. Pat. No. 5,864,394 to Jordan III et al., U.S. Pat. No. 6,313,467 to Shafer et al., U.S. Pat. No. 6,633,831 to Nikoonahad et al., U.S. Pat. No. 6,862,096 to Vaez-Iravani et al., and U.S. Pat. No. 6,879,391 to Danko, which are incorporated by reference as if fully set forth herein. Furthermore, the system shown in FIG. 1 may be configured and used as a defect review system (i.e., as a system configured to “revisit” defects detected on the specimen to determine additional information about the defects such as defect type). For example, the defect review system may be configured to perform defect review of a specimen by generating a relatively high magnification image of the defects detected on the specimen (e.g., by using the BF channel described above to acquire such an image) such that additional information about the defects can be determined (e.g., by the processor described above) using the relatively high magnification image. Therefore, the one or more characteristics of the specimen determined by the system may include one or more characteristics of defects detected on the specimen. The one or more characteristics of the defects may be determined using any method and/or algorithm known in the art. Moreover, the system shown in FIG. 1 may be configured and used as a metrology system (i.e., as a system configured to measure one or more characteristics of one or more patterned features formed on the specimen). In one such embodiment, the one or more characteristics include one or more dimensions of one or more patterned features formed on the specimen. In another embodiment, the one or more characteristics include a shape of one or more patterned features formed on the specimen. The metrology system may be configured to determine these and any other characteristics of the specimens described herein by performing any other measurements known in the art such as optical critical dimension (OCD) measurements. The embodiments of the system shown in FIG. 1 may be further configured as described herein. In addition, the system may be configured to perform any step(s) of any of the method embodiments described herein. The embodiments of the system shown in FIG. 1 have all of the advantages of other embodiments described herein. FIG. 1 also illustrates a system configured to provide illumination of a specimen for a process performed on the specimen. The system includes an electrodeless lamp (e.g., light source 10) configured to generate light. The system is further configured such that the light illuminates specimen 16 during the process. For instance, as described above, the system may include an illumination subsystem, which as described above, may include beam splitter 12 and objective 14 that are configured to direct light from light source 10 onto the specimen during the process such that the light illuminates the specimen during the process. In addition, the electrodeless lamp may be configured to direct the light onto the specimen during the process. Furthermore, the system may include any other suitable optical component(s) known in the art configured to direct the light from the electrodeless lamp to the specimen during the process. This system may be further configured as described herein. The embodiments described herein are generally configured to use one or more electrodeless lamps for patterned wafer inspection, other specimen inspection (unpatterned wafer inspection, reticle inspection), or metrology. In particular, one embodiment of a method for providing illumination of a specimen for inspection includes illuminating the specimen during the inspection with light generated by an electrodeless lamp. This method may include any other step(s) of any other method(s) described herein. The steps of the method may be performed as described herein. The electrodeless lamp used in the method may be configured according to any of the embodiments described herein. In addition, the method may be performed by any of the system embodiments described herein. Furthermore, the embodiment of the method described above has all of the advantages of other embodiments described herein. In one embodiment, the electrodeless lamp has an emissivity of greater than about 0.1. In another embodiment, the light generated by the electrodeless lamp includes DUV light, UV light, visible light, or some combination thereof. In an additional embodiment, the light generated by the electrodeless lamp includes broadband light. In some embodiments, the light generated by the electrodeless lamp includes light in a band from about 180 nm to about 450 nm. In a further embodiment, the light generated by the electrodeless lamp includes light in a spectral region from about 200 nm to about 450 nm. In yet another embodiment, the electrodeless lamp includes a plasma from which collected radiation between about 200 nm and about 450 nm is greater than about 3 W. The electrodeless lamp includes an electrodeless produced plasma. In particular, in one embodiment, the electrodeless lamp includes a plasma excited without introducing electrodes or a heat sensitive material near a region of the plasma. Electrodeless produced plasmas can be advantageously used to provide relatively high brightness radiation in the DUV region. In addition, electrodeless produced plasmas can be used to provide substantially high brightness radiation in the DUV, UV, and visible regions, or some combination thereof. This broadband spectral brightness has value for flexible, sensitive wafer inspection today and in the near future. The performance of the electrodeless lamps described herein can be optimized for microelectronics inspection applications in a number of ways. For example, optimizing the operation of DUV electrodeless lamps for use as sources in inspection applications such as semiconductor wafer inspection may include optimizing the pressure, gas type, energy deposition, energy deposition profile, or some combination thereof of the lamp while at the same time eliminating the need for electrodes. The targeted properties of the plasma-based electrodeless light source may include an energy pumped plasma from a gas or gas mixture, emissivity (hence pressure) of at least about 0.1 (although the emissivity may be about 0.05, about 0.1, about 0.2, etc.), partial pressure in a range of about 1 atm to about 40 atm or at least 1 atm, a plasma range limited to a relatively small volume between about 0.1 mm to about 2 mm (e.g., about 0.5 mm) in any direction to conservatively manage input, an etendue that substantially matches an illumination etendue, a managed heat, temperature of the plasma between about 9,000 K and 20,000 K, a plasma excited in a way that does not introduce electrodes or other heat sensitive materials near the plasma region, and an entire light source assembly configured to allow relatively efficient transmission of light in the wavelength band of about 180 nm to about 450 nm and with sufficient etendue to substantially match the illumination requirements of the inspection system. In one embodiment, therefore, the electrodeless lamp is configured to have an etendue that substantially matches illumination requirements of the system. In addition, the shortest wavelength of light emitted by the lamp embodiments described herein may vary depending on the housing of the lamp embodiments. For example, if the lamp housing is formed of a material that is relatively transparent at wavelengths of about 150 nm and above, the lamp may be configured for inspection applications at wavelengths of about 150 nm and above. Therefore, the electrodeless lamps described herein may be used to provide light in the VUV wavelength range in addition to or instead of light in other wavelength ranges described herein. Briefly, some advantages of using an electrodeless lamp as a relatively high brightness source include: a) elimination of electrodes in the lamp provides a lamp that does not degrade in time; b) the elimination of electrodes allows the lamp to be designed so that substantially all of the excitation energy can be deposited in the region of the lamp in which energy is collected by an illumination subsystem or lamp optics; c) the geometry of the plasma can be shaped to substantially match that of the collection optics; d) a cylindrical geometry can be generated which, when observed axially, can produce a lamp brightness in excess of that available from a spherically symmetric source; e) higher brightnesses can be achieved compared to electrode produced plasmas due to 1) the ability to concentrate an excitation source in the region of interest thereby not having to contend with repelling electrons in the excitation region and 2) the ability to achieve substantially higher excitation power densities and hence temperatures; f) ohmic losses in the lamp (e.g., unused ohmic losses in the electrodes of currently used lamps) are substantially eliminated making for a higher efficiency lamp; and g) the elimination of electrodes eliminates a relatively large source of short term and long range degradation and, importantly, variability and noise in lamp output and spectrum. In one embodiment, the electrodeless lamp includes a plasma generated using a single gas. In a different embodiment, the electrodeless lamp includes a plasma generated using a combination of gases. In another embodiment, the electrodeless lamp is filled with a gas that includes argon (Ar), krypton (Kr), xenon (Xe), fluorine (F), F dimers, chlorine (Cl), Cl dimers, mercury (Hg), nitrogen trifluoride (NF3), sulfur hexafluoride (SF6), a rare gas, a rare earth gas, a transition metal gas, a lanthanide metal gas, a halide containing gas, a Hg halide gas, or some combination thereof. In one example, nontraditional fill gases may be used in an electrodeless lamp for DUV inspection applications in which the wavelengths of interest are roughly in the spectral region from about 200 nm to about 450 nm. In addition to commonly used gases such as Ar, Kr, Xe, and Hg, gases such as Cl dimers, F dimers, rare earths, transition metals, and lanthanide metals are capable of providing substantially favorable working media in this wavelength range. These materials may be introduced to the lamp in the form of molecular species with relatively high vapor pressures. Example of appropriate gases also include, but are not limited to, Hg halides, NF3, SF6, diatomic halogens such as diatomic chlorine (Cl2), and a host of other combination gases. These gases will only be present as atomic constituents within the relatively high temperature plasma, and their emission can be optimized in the wavelength range of about 200 nm to about 450 nm, for example, by varying the plasma temperature. Feed material (fill materials at room temperature), which are atomic already or which are diatomic gases of a single atomic species, furthermore, will not be consumed in the apparatus. In one embodiment, the light generated by the electrodeless lamp includes excimer radiation. In one such embodiment, the electrodeless lamp includes about 1 bar or more of background rare gas and about 1 bar or less of a halide containing gas. For example, gas mixtures of Ar and F, in the case of relatively high background pressure or partial pressure (1 bar roughly or more) of Ar, will advantageously give rise to excimer emission (emission of F on a background of Ar) in a relatively copious quantity. In addition, unlike excimer laser light sources, the excimer emission of the lamp embodiments described herein is incoherent emission. Furthermore, unlike excimer laser light sources that produce narrowband light, the lamp embodiments described herein produce broadband light. Therefore, mixtures of Ar or Kr, for example, with diatomic halide species are particularly attractive feed materials. Ideal gases for use in embodiments described herein may have relatively high absorption of light at a wavelength of about 1 μm in the plasma state, relatively high emissivity at wavelengths from about 250 nm to about 400 nm, relatively low emissivity outside of wavelengths from about 250 nm to about 400 nm, ignite relatively easily, and do not substantially attack the glass or other materials of the lamps and do not leak out of the glass or other materials of the lamp. The plasma temperature in the region of highest brightness can be readily controlled and held substantially constant using excitation source pumped plasmas. It may also be desirable to optimize the brightness and average power of the lamp without exceeding a blackbody temperature that would produce substantial amounts of “out of band” DUV radiation above the bandgap for absorption of common UV transparent materials such as fused silica, magnesium fluoride (MgF2), and similar materials. For example, while temperatures as high as about 50,000 K can be achieved in discharges (e.g., radio frequency (RF) excited discharges and light produced discharges at relatively high pump powers and tight focus), it is important to recognize that above about 20,000 K the amount of blackbody radiation produced above the bandgap of the containing envelope of the lamp, whether the envelope is formed of fused silica, MgF2, lithium fluoride (LiF), or other UV transparent materials, is sufficiently high such that the envelope will absorb the radiation and fracture or melt. Nearly three orders of magnitude more radiation within absorbing regions of fused silica is produced in a temperature range of about 25,000 K to about 50,000 K than the 10,000 K plasma range. Accordingly, exciting the plasma to temperatures between about 10,000 K and about 20,000 K is easily achieved and maintained in a properly designed electrodeless pumped plasma. Configuring the focus of the excitation source or excitation sources used to sustain the plasma action appropriately is advantageous. In particular, inspection systems most efficiently collect and deliver light to the specimen plane using certain plasma shapes and sizes. For BF inspection systems used beyond the year 2005, shrinking pixel sizes and increased imaging computer inspection speeds will demand that plasmas roughly 1 mm in diameter are provided. In one embodiment, the electrodeless lamp includes a cylindrically shaped plasma substantially matched to image onto the specimen in the system. For example, “hockey puck” geometries in which the thickness of the puck is substantially matched to the depth of focus in the system and the puck diameter is roughly about 1 mm or a couple of hundred of μm are preferred. Therefore, relatively high numerical aperture (NA) short focal length delivery from one or more excitation sources are expected to best approach this geometry. Light generated by a plasma that has a generally ellipsoidal shape may be directed to one or more reflectors or other optical components of the illumination subsystem that direct only some cylindrical section of the light generated by the plasma to the specimen. This cylindrical section of the light may be directed or reflected in some nearly parallel way to a mirror, condenser, homogenizer, or some combination thereof. The illumination optics used in the system for the lamp embodiments described herein may be selected such that about π sr from an about 4π sr plasma is directed to the specimen. In this manner, the entire cross-section of light generated by the plasma may not be directed to the specimen. In another embodiment, an excitation volume of the electrodeless lamp is substantially matched to a field of view of collection optics of a system configured to inspect the specimen. In one embodiment, the electrodeless lamp includes a plasma region having a volume of about 0.1 mm to about 2 mm in any direction. In an additional embodiment, the electrodeless lamp includes a plasma having a geometry shaped to substantially match collection optics of a system configured to inspect the specimen. In this manner, the plasma excitation may be shaped such that the excitation volume of the plasma is substantially matched to the collection optics field of view appropriate for inspection such as wafer and/or reticle inspection. The field of view on the wafer may have a shape such as a rectangular, square, or circular shape. In addition, the field of view on the wafer may be about 1000 pixels to about 8000 pixels wide. The size of the pixels may be about 50 nm to about 300 nm depending on the inspection application and inspection system configuration. The NA may be up to about 0.9. In addition, higher brightness is desirable as the etendue decreases. In some embodiments, the light from the lamp may not be directed to the specimen across all of the solid angles encompassed by the NA. Instead, the light from the lamp may be directed to the specimen across a “ring” within the NA that subtends a solid angle of about 10 degrees to about 15 degrees, which may vary depending on the NA of the illumination subsystem of the inspection system. In one embodiment, a system described herein includes one or more electrodeless lamps at pressures above about 0.5 atm (at their working temperatures) that are configured to produce light for inspection (e.g., wafer inspection). In some embodiments, the lamp(s) produce light in the region of wavelengths between about 200 nm and about 400 nm. For example, in one embodiment, the electrodeless lamp is at a pressure of above about 1 atm at a working temperature of the electrodeless lamp, and the light generated by the electrodeless lamp includes light in a spectral region from about 200 nm to about 400 nm. In another embodiment, the light generated by the electrodeless lamp has a spectral brightness exceeding about 2 W/mm2-sr in an integral region of an electromagnetic spectrum from about 200 nm to about 400 nm. In this manner, the system may include one or more electrodeless lamps as light source(s), and the one or more electrodeless lamps may have spectral brightness exceeding about 2 W/mm2-sr in the integral region of the electromagnetic spectrum from about 200 nm to about 400 nm. In addition, the one or more electrodeless lamps may have spectral brightness of about 10 W/mm2-sr to about 40 W/mm2-sr. In a further embodiment, the electrodeless lamp(s) are configured to generate in excess of about 3 W of average power within any band contained within the region between about 200 nm and about 450 nm. In this manner, in some embodiments, light generated by the electrodeless lamp has an average power in excess of about 3 W within any band in a region between about 200 nm and about 450 nm. Therefore, the electrodeless lamps described herein may be configured to generate broadband light that can be used for broadband inspection of a specimen. In addition, the electrodeless lamps are configured to generate incoherent light. In one embodiment, the electrodeless lamp includes a plasma driven by an oscillatory magnetic field. In another embodiment, the electrodeless lamp includes a plasma driven by an oscillatory electric field. In this manner, the excitation source may include an electromagnetic excitation source. For example, the electromagnetic excitation source may be an RF source that can generate about a 1 GHz to many GHz electric field. In another example, the electromagnetic excitation source may be a microwave cavity that is configured to generate electric and magnetic fields. The electromagnetic excitation source may function as a relatively high power amplifier that is focused to a relatively small region proximate the plasma. In a different embodiment, the excitation source includes an electron source. For example, the electron source may be an electron gun. Electrodeless lamps that include plasmas driven by an oscillatory magnetic or electric field may be further configured as described herein. In some embodiments, the system includes an excitation source for the excitation of the plasma(s) in the electrodeless lamp(s) in cylindrical geometries such that the plasma axis length does not produce an average plasma opacity over this region of greater than one e-folding from “end-cap” to “end-cap.” In this manner, the electrodeless lamp may include a plasma having a plasma axis length, and the plasma does not produce an average plasma opacity over the plasma axis length of greater than about 1 e-folding from one end cap to another end cap of the electrodeless lamp. In another embodiment, the system is configured to use excitation from one or more excitation sources to form disc or hockey puck shaped plasmas that are relatively well matched to image onto the wafer plane in inspection systems. In a further embodiment, the electrodeless lamp includes a plasma having a diameter of between about 100 μm and about 2 mm. In an additional embodiment, the system is configured to use one or more excitation sources to ignite a plasma in the electrodeless lamp, and the power of the excitation source(s) is in excess of about 100 W. In some embodiments, the system is configured to use one or more “igniter” electrodes in conjunction with the overall electrodeless produced plasma. These one or more electrodes may be used to reduce the intensity of the excitation source that initiates the plasma. In a further embodiment, the electrodeless lamp includes an electrodeless produced plasma in which the collected radiation between about 200 nm and about 450 nm is more than about 3 W. In an additional embodiment, one or more materials are introduced to the lamp(s). The one or more materials may include fill gases such as Ar, Kr, Xe, F, Cl, NF3, SF6, any other rare gas or halide containing gas, or some combination thereof. In another embodiment, the electrodeless produced plasma is configured to produce excimer radiation by using about 1 bar or more of background rare gas along with a similar or lower fill pressure (i.e., the initial or cold pressure) of halide containing gas. In one embodiment, the electrodeless lamp has a partial pressure in a range of about 1 atm to about 40 atm. In another embodiment, a fill pressure of gases in the electrodeless lamp is about 4 atm or higher. In some embodiments, the lamp is configured for fill pressures of gases to as much as about 10 atm or about 10 bar. In another embodiment, the lamp is configured for fill pressures of gases to as much as about 4 atm to about 10 atm or bar or higher. Higher fill pressures may be advantageous to increase the excitation of the plasma, which may increase the average power that can be achieved by the plasma. In other words, using higher fill pressures may advantageously increase the ratio of absorbed power to radiated power of the plasma. In one embodiment, the electrodeless lamp includes a plasma generated using a rare earth gas and a Hg gas. In one such embodiment, the light generated by the electrodeless lamp is in a spectral region from about 230 nm to about 480 nm. The electrodeless lamp may include an electrodeless produced plasma that includes a combination of rare earth (e.g., Xe, Ar, etc.) and Hg gases to optimize spectral brightness in the wavelength region of about 230 nm to about 480 nm. For example, the electrodeless produced plasma may include about 1 atm fill of Ar, about 4 atm or higher fill of Ar, about 1 atm fill of Xe, about 4 atm or higher fill of Xe, a combination of Hg and Xe, and about 1 atm fill of Xe with Cl2. In some embodiments, a fill gas in the electrodeless lamp has an opacity at a working temperature and pressure of the electrodeless lamp that does not exceed about 10% reabsorption of about 200 nm to about 450 nm radiation emitted from a center of the electrodeless lamp. In this manner, the opacity of fill gases used in the electrodeless lamp at the working temperature and pressure of the lamp does not exceed about 10% reabsorption of about 200 nm to about 450 nm radiation emitted from the center of the lamp. In another embodiment, a temperature of the plasma in the electrodeless lamp is between about 10,000 K and about 30,000 K for any of the fill gases described herein. In one embodiment, therefore, the electrodeless lamp includes a plasma at a temperature of about 10,000 K to about 30,000 K. However, in a different embodiment, the electrodeless lamp includes a plasma at a temperature of about 9,000 K to about 20,000 K. In one embodiment, the electrodeless lamp is substantially flat on one side and has a substantially hemispherical shape. For example, the electrodeless lamp may be substantially flat on one side (e.g., such that the lamp has a shape approximately similar to a hemisphere) to reduce the distance between the entrance of the excitation source to the working medium and its focal point. This concept and related bulb design concepts may be employed to optimize the shape of the plasma to the collector of the inspection system. In one embodiment, therefore, the electrodeless lamp includes a bulb configured to optimize a shape of a plasma within the bulb to a collector of a system configured to inspect the specimen. In one embodiment, the electrodeless lamp includes a bulb in which a focusing element is disposed such that the electrodeless lamp is further configured for substantially high NA focus. For example, in some embodiments, the electrodeless lamp includes a bulb with an internal lens or curved reflector to achieve relatively high NA focus. In addition, the plasma source may be positioned at approximately the center of a spherical reflector that will redirect some light generated by the plasma back into the plasma thereby causing further heating of the plasma. While the plasma may be relatively optically thin (and not substantially absorptive), if the Q of the cavity is relatively high (e.g., not much loss in the reflector or in the quartz bulb) then there are chances for photons to be absorbed in the plasma. For example, the plasma will radiate over almost 4π sr, but about π sr of the light may be collected. Therefore, the uncollected light may be used to reheat the plasma and drive up the temperature and brightness. The spherical reflector may have holes formed therethrough to allow for the collection of the light, but these holes may not reduce the Q much for photons that are bouncing back and forth across the spherical reflector away from the collection optics until they get absorbed by the plasma. To optimize this effect, the absorption at the reflector (1-R) may be small compared to the absorption at the plasma. As such, the reflector may have a substantially high R at the wavelengths at which the plasma radiates. The bulb wall absorption losses are also preferably relatively low for this to work well as high absorption at the bulb wall would reduce the overall cavity Q. This effect may combat the effect of the plasma burning away from the focal point of the excitation source. Pumping with reflected light over a substantially large NA would tend to counteract this effect. There are additional ways to excite a relatively high pressure, spatially limited plasma. For example, an RF electrical amplifier may be configured to drive a tuned inductor (e.g., a Helmholtz coil) or capacitor to create substantially large oscillatory magnetic and electric fields, respectively. A critical field strength will cause ionization and the resulting oscillatory electrons will drive plasma temperature in the same way that electrons drive discharge arc or inductive loop based plasma sources. FIGS. 2 and 3 illustrate various embodiments of an electrodeless lamp. In particular, FIG. 2 illustrates one method for delivering excitation power to a contained relatively small, relatively high pressure plasma. In this embodiment, a relatively high power amplifier is used to create focus to a relatively small region. As shown in FIG. 2, this embodiment of an electrodeless lamp includes RF amplifier 28 coupled to resonant matching network 30. The RF amplifier and the resonant matching network may include any suitable components known in the art. The resonant matching network may be configured to operate at about 50 ohms. The resonant matching network is coupled to Helmholtz coil 32 to create a relatively high strength oscillatory magnetic field. The Helmholtz coil may include any suitable Helmholtz coil known in the art. Relatively high pressure ampule 34 (having dimensions of about 1 mm by about 2 mm and having a roughly ellipsoidal shape) contains the plasma gas mixture. The ampule may have any other suitable configuration. The plasma gas mixture may include any of the gas mixtures described herein. As further shown in FIG. 2, light 36 is output from the ampule, which may include DUV light UV light, visible light, or some combination thereof. The embodiment of the electrodeless lamp shown in FIG. 2 may be further configured as described herein. The embodiment of the electrodeless lamp shown in FIG. 2 may be included in any of the systems described herein. In addition, the embodiment of the electrodeless lamp shown in FIG. 2 has all of the advantages of other embodiments described herein. FIG. 3 illustrates another method for delivering excitation power to a contained relatively small, relatively high pressure plasma. As shown in FIG. 3, this embodiment of an electrodeless lamp includes RF amplifier 38 coupled to resonant matching network 40. The RF amplifier and the resonant matching network may include any suitable components known in the art. The resonant matching network may be configured to operate at approximately 50 ohms. The resonant matching network is coupled to capacitor plates 42 that are configured to create a relatively high strength oscillatory electric field. In this manner, electromagnetic sources may be used to drive RF to a many GHz resonant electric field. In a similar manner (not shown), electromagnetic sources may be used to drive microwave cavities with electric and magnetic fields. The capacitor plates may have any suitable configuration known in the art. Relatively high pressure ampule 44 (having dimensions of about 1 mm by about 2 mm and having a roughly ellipsoidal shape) contains the plasma gas mixture. The ampule may have any other suitable configuration. The plasma gas mixture may include any of the gas mixtures described herein. As further shown in FIG. 3, light 46 is output from the ampule, which may include DUV light, UV light, visible light, or some combination thereof. The embodiment of the electrodeless lamp shown in FIG. 3 may be further configured as described herein. The embodiment of the electrodeless lamp shown in FIG. 3 may be included in any of the systems described herein. In addition, the embodiment of the electrodeless lamp shown in FIG. 3 has all of the advantages of other embodiments described herein. The configuration of the electrodeless lamps described herein may be further selected based on Babucke et al., J. Phys. D, App. Phys. 24 1316 (1991), Derra et al., J. Phys. D, App. Phys., 38 2995, A. T. M. Wilburs and D. C. Schram, S. Quant. Spec. and Radiat. Transfer, 46 299-308 (1991), and D. Erskine et al., J. Quant. Spec. and Radiat. Transfer, 51(12), 97-100 (1994), which are incorporated by reference as if fully set forth herein. The following description generally relates to electrodeless lamps configured as laser sustained plasma (LSP) lamps or LSP light sources (LSPLSs) that may be optimally configured for wafer inspection and other applications described herein. The terms “electrodeless lamp,” “LSP lamp,” “LSP light source” and “LSPLS” are used interchangeably herein. Substantially high brightness and substantially high average power lamps are highly desired as sources that can provide DUV radiation for illumination and inspection of semiconductor wafers and other specimens described herein. As semiconductor transistor dimensions continue to shrink with CDs approaching several tens of nanometers, wavelengths well below about 300 nm are essential for the resolution of defects. Relatively large bandwidth lamps are attractive for such applications due to their ability to reduce color variations (e.g., reflectivity differences due to thin film stack thickness variation) and optimize contrast by selecting desirable bands for various material types within the lamp spectrum. Selecting spectral bands for different materials types can be performed as described in commonly assigned U.S. patent application Ser. No. 10/410,126 by Lange et al., filed Apr. 4, 2003, published as U.S. Patent Application Publication No. 2004/0201837 on Oct. 14, 2004, and commonly assigned U.S. patent application Ser. No. 10/933,873 to Lange et al., filed Sep. 3, 2003, published as U.S. Patent Application Publication No. 2005/0052643 on Mar. 10, 2005, all of which are incorporated by reference as if fully set forth herein. However, brightness far exceeding that of 1 kW commercial lamps (about 1 W/mm2-sr to about 5 W/mm2-sr for wavelengths from about 230 nm to about 370 nm) is greatly desired to provide the brightest possible illumination within the field of view of the optical inspection microscope. Illumination with a source sufficiently bright to saturate the inspection system sensor generally provides the highest sensitivity to defects. In addition, extremely high brightness DUV sources allow the reduction of inspection time (and thereby increased throughput) by effecting saturation of the sensor on the smallest timescales possible (subject to limits for preventing wafer and microscope damage). However, electrically driven lamps have brightness and average power limits due to the inability of such lamps to contain the energy deposition from electrodes within a relatively small volume due to electron-electron repulsion, the limited emissivity of gases as black body emitters, the rapid erosion of electrodes made from refractory materials due to the presence of relatively large current densities at the cathodes, and the inability to contain dopants for relatively long periods of time within refractory cathodes in order to lower the operating temperature of the cathodes at the required emission current. At the same time, additional methods of exciting gases to energies and energy densities capable of substantially high brightness DUV emission are available. In particular, laser excitation of relatively high pressure atomic and molecular vapor can provide substantially intense DUV light. Indeed, lithography tool manufacturers have for nearly 15 years been pursuing the development of a so-called extreme UV (EUV) light source in which laser produced (or discharge produced) plasmas are used to pump highly ionized atoms to a degree such that they efficiently provide radiation at a wavelength of 13 nm. Sources obtained by direct pulsed laser excitation are substantially expensive however; too expensive for wafer inspection tools. Fortunately, it has been known for over 30 years that continuous-wave (cw) sustained laser plasmas can provide substantially efficient production of DUV radiation for applications including those discussed herein (see, for example, D. L. Franzen, J. Appl. Phys. 44(4), 1727-1732 (1972) and D. L. Franzen, Appl. Phys. Lett., 21, 62-64 (1972), which are incorporated by reference as if fully set forth herein). The embodiments described herein may be configured to optimize the operation of DUV lamps and the delivery of their DUV radiation to optical objectives for their use as sources in semiconductor wafer inspection applications and other applications described herein. Such optimization may be achieved by optimizing the pressure, gas type, energy deposition, energy deposition profile, or some combination thereof of the lamp to efficiently couple light generated by the lamp to a standard wafer inspection objective with a time delay integration (TDI) sensor or any other suitable sensor known in the art, which is used to measure the reflected or scattered radiation from the illuminated wafer plane. Prior to describing the embodiments further, it is noted that a substantial body of literature exists which supports the design of LSPs for applications described herein and subsequent design and optimization for such applications. A great number of authors (see, for example, R. Wiehle, B. Witzel, H. Helm, and E. Cormier, Phys. Rev. A, 67, 063405 (2003) and V. V. Kostin, R. B. Borisov, I. V. Degtyarev, and V. E. Fortov, Phyzika Plasmy 23 (2), 102-109, 1997, both of which are incorporated by reference as if fully set forth herein) have noted that extremely intense fields (e.g., about multi-gigawatt/cm2 laser radiance) are required to initiate breakdown (plasma formation) in a standing or flowing bulk gas composed of primarily ground electronic state species. However, a great many authors have measured the cross section for ionization of highly excited, often metastable, electronic states of neutral atoms and molecules (see, for example, A. Takahashi, T. Okada, T. Hiyama, M. Maeda, K. Uchino, R. Nohdomi, and H. Mizoguchi, App. Phys. Lett., 77(25), 4115-4117 (2000), H. Tanaka, A. Takahashi, T. Okada, M. Maerda, K. Uchino, T. Nishisaka, A. Sumitani, and H. Mizoguchi, Appl. Phys. B, 74, 323-326 (2002), A. Takahashi and T. Okada, Jap. Journ. Appl. Phys., 37, Part 2, No. 4A, L390-L393, (1998), D. L. Franzen, J. Appl. Phys. 44(4), 1727-1732 (1972), D. L. Franzen, Appl. Phys. Lett., 21, 62-64 (1972), and S. Schohl, D. Klar, T. Kraft, H. A. J. Meijer, M-W. Ruf, U. Schmitz, S. J. Smith, and H. Hotop, Zeit. fur Physik D, Atoms, Molecules and Clusters, 21(1) 25-39 (1991), all of which are incorporated by reference as if fully set forth herein) and have found that lower fluences can be used to sustain plasmas that have been initiated by other means. These fluences are more likely in the range of about 1 MW/cm2 and therefore can be formed using currently available low cost cw lasers of various types. Applications investigated have included LSPs for excimer laser radiation production (see, for example, A. Takahashi and T. Okada, Jap. Journ. Appl. Phys., 37, Part 2, No. 4A, L390-L393, (1998), A. Takahashi, T. Okada, T. Hiyama, M. Maeda, K. Uchino, R. Nohdomi, and H. Mizoguchi, App. Phys. Lett., 77(25), 4115-4117 (2000), and H. Tanaka, A. Takahashi, T. Okada, M. Maerda, K. Uchino, T. Nishisaka, A. Sumitani, and H. Mizoguchi, Appl. Phys. B, 74, 323-326 (2002), all of which are incorporated by reference as if fully set forth herein), supersonic plasma jets for propulsion applications (see, for example, Z. Szymanski and S. Filipkowski, J. Appl. Phys., 69(6), 3480-3484 (1990), Z. Szymanski, Z. Peradzynski, J. Kurzyna, J. Hoffman, M. Dudeck, M. ee Graaf, and V. Lago, J. Phys. D: App. Phys. 30, 998-1006 (1997), and J. M. Girard, A. Lebehot, and R. Compargue, J. Phys. D: App. Phys. 26, 1382-1393 (1993), all of which are incorporated by reference as if fully set forth herein), the production of electron sources (see, for example, A. B. Lewis, D. F. Grosjean, and P. Bletzinger, 2nd Inter. Conf on Plasma Science IEEE, p. 45 (1975), which is incorporated by reference as if fully set forth herein), and the detection of metastable atoms (see, for example, J. E. Daily, R. Gommers, E. A. Cummings, D. S. Durfee, and S. D. Bergeson, Phys. Rev. A, 71, 043406 (2005), which is incorporated by reference as if fully set forth herein) to name just a few. In one embodiment, the systems described herein are configured for patterned wafer inspection. For example, in one embodiment, the light generated by the plasma has a brightness of about 10 W/mm2-sr to about 50 W/mm2-sr in a spectral region from about 200 nm to about 400 nm. In this manner, light driven produced plasmas can be used to provide substantially high brightness radiation in the DUV region (about 10 W/mm2-sr to about 50 W/mm2-sr). This spectral brightness is important for wafer inspection systems on the market today and in the near future. In addition, the performance of these electrodeless lamps can be optimized for the application of microelectronics inspection in a number of ways. Briefly, some advantages of using light driven or light produced plasmas as relatively high brightness sources are: a) the elimination of electrodes provides for a lamp that does not degrade in time; b) the elimination of electrodes allows for the lamp to be designed so that substantially all of the excitation energy can be deposited in the region of the lamp in which energy is collected by the illumination subsystem or lamp optics; c) the geometry of the plasma can be shaped to substantially match that of the collection optics; d) a cylindrical geometry can be generated which, when observed axially, can produce a lamp brightness in excess of that available from a spherically symmetric source; e) higher brightnesses can be achieved compared to electrode produced plasmas due to 1) the ability to concentrate photons in the region of interest thereby not having to contend with repelling electrons in the excitation region and 2) the ability to achieve substantially higher excitation power densities and hence temperatures; f) ohmic losses in the lamp (e.g., unused ohmic losses in the electrodes of currently used lamps) are substantially eliminated making for a higher efficiency lamp; and g) the elimination of electrodes eliminates a relatively large source of short term and long range degradation and, importantly, variability and noise in lamp output and spectrum. In one embodiment, the electrodeless lamp includes a fill gas, and the fill gas includes Ar, Kr, Xe, F, Cl, Cl dimers, F dimers, a homogenous diatomic gas, NF3, SF6, nitric oxide (NO), Hg, a halide containing gas, Hg halides, diatomic halides, halides, a rare gas, rare earths, transition metals, lanthanide metals, or some combination thereof. For example, in one embodiment, the electrodeless lamp includes a plasma generated using a single gas. In a different embodiment, the electrodeless lamp includes a plasma generated using a combination of gases. In another embodiment, the electrodeless lamp is filled with a gas that includes Ar, Kr, Xe, F, F dimers, Cl, Cl dimers, Hg, NF3, SF6, a rare gas, a rare earth gas, a transition metal gas, a lanthanide metal gas, a halide containing gas, a Hg halide gas, or some combination thereof. In this manner, fill gases that can be used for the LSP lamps described herein include Ar, Kr, Xe, F, Cl, NF3, SF6, NO, or any other rare gas or halide containing gas, alone or in some combination thereof. In one example, nontraditional fill gases may be used in LSP lamps for DUV inspection applications in which the wavelengths of interest are roughly in the spectral region from about 200 nm to about 450 nm. In addition to commonly used gases such as Ar, Kr, Xe, and Hg, gases such as Cl dimers, F dimers, rare earths, transition metals, and lanthanide metals are capable of providing substantially favorable working media in this wavelength range. These materials may be introduced to the lamp in the form of molecular species with relatively high vapor pressures. Examples of appropriate gases also include, but are not limited to, Hg halides, NF3, SF6, diatomic halogens such as Cl2, NO, and a host of other combination gases. These gases will only be present as atomic constituents within the relatively high temperature plasmas, and their emission can be optimized in the wavelength range of about 200 nm to about 450 nm, for example, by varying the plasma temperature. Feed materials (fill materials at approximately room temperature), which are atomic already or which are diatomic gases of a single atomic species, furthermore, will not be consumed in the apparatus. In one embodiment, the light generated by the plasma includes excimer radiation. In one such embodiment, the electrodeless lamp includes about 1 atm or more of background rare gas and about 1 atm or less of a halide containing gas. For example, gas mixtures of Ar and F, in the case of relatively high background pressure or partial pressure (1 bar roughly or more) of Ar, will advantageously give rise to excimer emission (emission of F on a background of Ar) in a relatively copious quantity. In addition, unlike excimer laser light sources, the excimer emission of the embodiments described herein is incoherent emission. Furthermore, unlike excimer laser light sources that produce narrowband light, the embodiments described herein can produce broadband light. Therefore, mixtures of Ar or Kr, for example, with diatomic halide species are particularly attractive feed materials. Ideal gases for use in embodiments described herein may have relatively high absorption in the plasma state, relatively high emissivity at wavelengths from about 250 nm to about 400 nm, relatively low emissivity outside of wavelengths from about 250 nm to about 400 nm, ignite relatively easily, and do not substantially attack the glass or other materials of the lamp and do not leak out of the glass or other materials of the lamp. In one embodiment, a temperature of the plasma is held substantially constant by the excitation light. For example, the plasma temperature in the region of highest brightness can be readily controlled and held substantially constant using light driven pumped plasmas. It may also be desirable to optimize the brightness and average power of the lamp without exceeding a blackbody temperature that would produce substantial amounts of “out of band” DUV radiation above the bandgap for absorption of common UV transparent materials such as fused silica, MgF2, and similar materials. For example, while temperatures as high as about 50,000 K can be achieved in discharges (e.g., RF excited discharges and light driven produced discharges at relatively high pump powers and relatively tight focus), it is important to note that above about 20,000 K the amount of blackbody radiation produced above the bandgap of the containing envelope of the lamp, whether the envelope is formed of fused silica, MgF2, LiF, or other UV transparent material, is sufficiently high such that the envelope will absorb the radiation and fracture or melt. Nearly three orders of magnitude more radiation within absorbing regions of fused silica is produced in a temperature range of about 25,000 K to about 50,000 K than the 10,000 K plasma range. Accordingly, exciting the plasma to temperatures between about 10,000 K and about 20,000 K is easily achieved and maintained in a properly designed light driven pumped plasma. In this manner, the brightness of the lamp and its average power can also be optimized without exceeding a blackbody temperature that would produce substantial amounts of DUV radiation above the bandgap for absorption of common UV transparent materials such as fused silica, MF2, and similar materials, which are preferably used to construct the objective for the inspection system. A major advantage of LSP lamps is that lasers can deposit the energy of photons in substantially small regions of a relatively high pressure bulb as opposed to the far more diffuse energy deposition of an electrically excited plasma. One result of this extreme concentration of energy is the substantially larger temperature gradients in the lamp from the core of the plasma to the lamp wall. Additionally, substantially higher temperatures are obtainable with LSPs due to the concentration of energy and the elimination of waste heat terms such as ohmic losses and minimization of convective and conductive cooling. In this manner, the LSP lamps described herein may be configured as relatively high temperature gradient LSP lamps. In particular, the lamps described herein may be operated in a manner that permits relatively intense radiation to be obtained at DUV and even VUV wavelengths that cannot be obtained from electrically sustained lamps. This intense radiation is extremely important and is even new physics and occurs via totally unexpected behavior in these lamps. The embodiments described herein have applications to sub-200 nm optical inspection systems and can even be used to provide 121 nm light and could serve as light sources for the next ten years. A 121 nm light source configured as described herein may be used with an all-reflective objective. Such light sources are advantageous in that e-beam inspection systems would not have to be relied upon for future generations of inspection tools. The temperature gradient in the LSP lamp is so large that radiation that is normally trapped and completely self-reversed (absent) in electrically driven plasmas is present in abundance in the LSP lamp. For example, it is estimated that several watts of average power can be achieved at about 185 nm and at about 121 nm. Any strong line of an atomic spectrum that terminates upon the ground or low lying (within about a volt) of the ground state can be counted on for relatively strong emission and use in inspection. Such relatively strong emission may also have significant implications for lithography beyond 193 nm immersion lithography. As a result, strong emission from such plasmas may be obtained on substantially strong atomic transitions that terminate at the ground state or on low (populated) metastable states of the neutral atom (or ion) in the lamp. Whereas the substantially strong resonance line of Hg at 2537 Å is totally missing in electrically driven plasma lamps, this resonance line can be the source of substantially strong emission in laser driven plasmas. This substantially strong resonance line appears to be due to the substantially large Doppler broadening of the atoms in the core of the lamp followed by rapidly diminishing Doppler linewidths in the regions immediately outside of the plasma. As a result, resonance radiation lines are not trapped (although self reversed) and form the basis for substantially high spectral brightness in laser sustained lamps. Therefore, species that once were thought to be of no value in lamps for the production of, for example, UV light can now be used to generate copious amounts of convenient and useful DUV radiation for wafer inspection and other applications described herein. Example(s) of species of interest include Ba I (neutral barium where I means a neutral atom), which emits resonance lines at 2409 Å, cobalt (Co) I which emits resonance lines at 2402 Å, magnesium (Mg) I which emits resonance lines at 2025 Å, nickel (Ni) I which emits resonance lines at 2026 Å, scandium (Sc) I which emits resonance lines at 2000 Å, Ni I (terminating on the 879 cm-1 electronic metastable state), and numerous other species in the periodic table. Many of these atoms can be readily vaporized at convenient temperatures in a lamp and used in the applications described herein. In one embodiment, therefore, the plasma includes one or more species that fluoresce (e.g., normally fluoresce strongly) in a region between about 180 nm and about 350 nm to a ground electronic state. In another embodiment, the plasma includes species that fluoresce (e.g., normally fluoresce strongly) in a region between about 180 nm to about 350 nm to electronic metastable states within about 0.5 ev of a ground electronic state. Therefore, such a plasma may be substantially populated by such species at temperatures between room temperature and about 2000° C. In an additional embodiment, an LSP lamp described herein is configured to contain one or more such species. For example, in some such embodiments, the one or more species include Hg that emits resonance lines at 2537 Å, Ba I that emits resonance lines at 2409 Å, Co I that emits resonance lines at 2402 Å, Mg I that emits resonance lines at 2025 Å, Ni I that emits resonance lines at 2026 Å, Sc I that emits resonance lines at 2000 Å, Ni I terminating on a 879 cm-1 electronic metastable state, or some combination thereof. In one embodiment, the system includes at least one heat source located proximate to the electrodeless lamp and configured to maintain atoms in the plasma in the vapor phase. In this manner, one or more heat sources (e g., electrical heaters) may be disposed proximate to the LSP lamp (e.g., around the LSP lamp) to keep the atoms in the vapor phase in the LSP lamp. In another embodiment, temperature gradients are optimized via highly focused laser pumping (e.g., by the focusing optics described herein) to optimize the spectral brightness of emission from the types of feed material described herein. In some embodiments, atoms or molecules that form the one or more species described above are present in the electrodeless lamp prior to generation of the plasma in a quantity or quantities that limit the vapor pressure of the atoms or molecules in the electrodeless lamp such that substantially all of the atoms or molecules are vaporized before the lamp reaches operating temperature. For example, such atoms (or molecules) may be added to the LSP lamp in quantities (from about 1 mg to about 1 g) that limit their vapor pressure in the lamp at relatively high temperatures (e.g., such that substantially all of the material is vaporized before the lamp operating temperature is reached). In some embodiments, the one or more species described above include atoms formed by decomposition of feed molecules in the electrodeless lamp. For example, feed molecules that decompose to form atoms at relatively high temperatures and that fluoresce in a manner as described above may be added to the LSP lamp. In one embodiment, the electrodeless lamp includes one or more operating gases that have atomic transitions from electronically excited states to a ground electronic state of one or more corresponding neutral atoms or a state within about 1 eV to about 2 eV of the ground electronic state. In this manner, the LSP lamps described herein may be configured for use with operating gases that have relatively strong atomic transitions from the electronically excited states to the ground electronic state or any state lying within about 1 (or 2) eV of the ground electronic state of the neutral atom. In one embodiment, the electrodeless lamp includes feed molecules of which about 1% or greater are dissociated at an operating temperature proximate a center of the plasma. In one such embodiment, the feed molecules include iodine (I2), chlorine (Cl2), bromine (Br2), sulfur (S2), nitrogen (N2), oxygen (O2), a diatomic gas, one or more homonuclear diatomic feed materials capable of recombining to form only their corresponding molecular species, one or more rare gases, or some combination thereof. In another embodiment, the electrodeless lamp includes feed molecules of which about 1% or greater are dissociated at an operating temperature of about 600 K to about 25,000 K. In this manner, the lamp may be configured for use with feed molecules that are largely (e.g., about 1% or greater) dissociated at the operating temperature of the center of the plasma (greater than about 600 K and to as high as about 25,000 K). Examples of such feed molecules are I2, Cl2, Br2, S2, N2, O2, and other diatomic species. In an additional embodiment, the feed molecules include homonuclear diatomic feed materials that can only recombine to form their initial molecular species. In some embodiments, the species described herein are used by themselves, as mixtures with other diatomics, or in the presence of or without rare gases in the mixture. In one embodiment, the electrodeless lamp includes diatomic hydrogen (H2). In one such embodiment, the light generated by the plasma has a wavelength of about 121 nm. In another such embodiment, the light generated by the plasma has a wavelength of about 121 nm, about 937 nm, about 949 nm, about 972 nm, about 1025 nm, or some combination thereof. In this manner, H2 may be used in the LSP lamp to generate radiation at a wavelength of about 121 nm and/or radiation at a wavelength of about 1025 nm, about 972 nm, about 949 nm, and/or about 937 nm. In another embodiment, Hg atoms are used to generate radiation at a wavelength of about 253.7 nm and/or about 185 nm. In some embodiments, atomic or molecular species are used in natural isotopic abundance in the lamps described herein. In another embodiment, atomic or molecular species are used in the lamps described herein that are isotopically enriched to arbitrary purity such that greater than about 90% of the radiation is emitted within a spectral bandwidth consistent with imaging using a purely refractive objective. In this manner, the plasmas described herein may be configured to generate narrowband light and/or monochromatic light. In some embodiments, the LSP lamps described herein are at least partially constructed of glasses or windows that are transparent (e.g., more than about 50% transparent) at the operating wavelength of interest. Operating envelope materials may include fused silica, CaF2, or other amorphous or crystalline materials. In a further embodiment, these lamps are used in a system configured to operate at one or more VUV wavelengths that is purged of substantially all species in the atmosphere that absorb at the operating wavelength of interest. Examples of systems configured for operation in the VUV regime are illustrated in commonly assigned U.S. patent application Ser. No. 10/845,958 by Fielden et al. filed May 14, 2004 published as U.S. Patent Application Publication No. 2005/0252752 on Nov. 17, 2005, and commonly assigned U.S. patent application Ser. No. 10/846,053 by Fielden et al. filed May 14, 2004 published as U.S. Patent Application Publication No. 2005/0254050 on Nov. 17, 2005, all of which are incorporated by reference as if fully set forth herein. The LSP lamps described herein may be used in any of the systems described in these patent applications. In addition, the systems described herein may be further configured as described in these patent applications. In an additional embodiment, F, Cl, Br, and I lamps are operated at their resonance wavelengths. Note, the resonance wavelength of Cl is about 138 nm, and the resonance wavelength of F is about 125 nm. Therefore, the lamps described herein may be configured to generate light at VUV wavelengths such as 125 nm and 138 nm. In another embodiment, the lamps described herein are used with any filter(s) configured to selectively discriminate against particular fine structure or hyperfine structure emission in natural isotopic abundance or isotopically purified lamps. In one embodiment, the plasma has a diameter of about 0.5 mm to about 1 mm. The diameter and/or the shape of the plasma can be controlled by focusing optics that focus excitation light to the plasma (possibly in combination with another subsystem such as a gas flow subsystem) as described further herein. For example, in one embodiment, the focusing optics are configured to focus the excitation light to a cylindrical-shaped region within the electrodeless lamp. In one such embodiment, the cylindrical-shaped region has a diameter of about 0.5 mm to about 1 mm and a thickness of about 100 μm to about 200 μm. Configuring the focus of the excitation light (e.g., from the light driver or drivers) used to sustain the plasma action appropriately is advantageous. Namely, inspection systems most efficiently collect and deliver to the specimen plane certain plasma shapes and sizes. For BF inspection systems used beyond the year 2005, the shrinking pixel sizes and increased imaging computer inspection speeds will demand that plasmas about 0.5 mm to about 1.0 mm in diameter are provided. “Hockey puck” three-dimensional (3D) shaped geometries in which the thickness of the puck is substantially matched to the depth of focus of the inspection system and in which the puck diameter is about 0.5 mm to about 1.0 mm or so are preferred. Therefore, relatively high NA short focal length beam delivery from one or more light drivers is expected to best approach this geometry. In addition, the shape of the plasma can be altered and/or controlled as described further herein (e.g., by the focusing optics possibly in combination with one or more elements of the system such as a gas flow subsystem) to match or substantially match one or more parameters and/or elements of a system such as an inspection system, a defect review system, a metrology system, an imaging system, a lithography system, etc. For example, in one embodiment, the plasma has a geometry shaped to substantially match collection optics of a detection subsystem of a system configured to inspect the specimen. In another embodiment, the plasma has a cylindrical shape substantially matched to image onto the specimen in the system. Such plasma shapes may be created, altered, and/or controlled as described further herein. In order to deposit substantially all of the radiation from the laser sustaining source into the plasma in a volume defined by a “hockey puck,” which has a thickness of about 100 μm to about 200 μm and a diameter of about 1 mm, the relatively high pressure gas in the lamp preferably absorbs substantially all of the pump excitation light within such a volume. In another embodiment, the electrodeless lamp includes a fill gas, and an opacity of the fill gas at a working temperature and pressure of the electrodeless lamp is less than or equal to about 10% reabsorption of light emitted from a center of the lamp within a spectral region from about 200 nm to about 450 nm. In another embodiment, the electrodeless lamp includes a fill gas at a gas pressure such that an opacity of the plasma does not prohibit a majority of the light generated by the plasma from exiting the lamp. For example, the gas type(s) and the gas pressure(s) are preferably selected such that the resulting plasma opacity (see, for example, J. L. Emmett and A. L. Schawlow, and E. H. Weinberg, J. Appl. Phys., 35(9), 2601-2604 (1964) and D. Erskine, B. Roznyal, and M. Ross, J. Quant. Spec. and Radiat. Transfer, 51(12), 97-100 (1994), which are incorporated by reference as if fully set forth herein) does not prohibit the majority of selected radiation (about 200 nm to about 300 nm, or about 200 nm to about 400 nm) from escaping the lamp and reaching the specimen plane through the objective. These two conditions, plasma opacity of emitted radiation and plasma absorption of pump radiation, can be used to determine the pressure of optimum fill for a LSP lamp. For example, pressures between about 5 atm and about 20 atm (at approximately room temperature) will generally fulfill these objectives. Therefore, in one embodiment, a fill pressure of the electrodeless lamp is about 5 atm to about 20 atm at room temperature. In one embodiment, a wavelength of the excitation light is less than about 10 μm. For example, in order for the light generation process to be efficient, the light used to drive the plasma is preferably optimally coupled to the lamp with as much of the light absorbed in the working region as possible. Relatively intense light fields may preferably be used since the absorption process is primarily multiphoton ionization followed by subsequent plasma absorption. Therefore, relatively good light source focus is desirable. In addition, since multiphoton ionization is a peak power process, (kw/cm2) generally scales as n, where the power of n is generally the number of photons from the light source used to reach the state of ionization sought from the electronic state of the neutral used as a feed. Therefore, as an example, n will equal 10 if one uses about 1 ev photons, the ionization potential of the atom used in the working medium is about 10 ev, and the ground electronic state is the atom of interest. Should an excited state of the atom at, say, about 8 ev, of excitation exist in the working region, two such photons are required. The above processes thus depend upon the power of n=10 and 2, respectively. Therefore, from the above description, it can be seen that relatively short wavelength sources may be desirable, certainly no longer than essentially about 10 μm in wavelength (see, for example, D. L. Franzen, J. Appl. Phys. 44(4), 1727-1732 (1972) and D. L. Franzen, Appl. Phys. Lett., 21 62-64 (1972), which are incorporated by reference as if fully set forth herein) in order to achieve efficient ionization. The above description also illustrates the importance of considerable numbers of metastable, highly excited, near ionization continuum states being present within the plasma in order to effectively couple to the radiation field at moderate fluences. The design of an optimum LSP light source for applications such as wafer inspection begins with the knowledge that: a) the field of view of broadband catadioptric objectives configured for use with radiation between about 200 nm to about 300 nm or about 200 nm to about 400 nm is on the order of about 1 mm; b) the shape of the LSP is preferably homogenized and configured to best fit a sensor footprint at the wafer plane in which sensor two-dimensional (2D) pixel counts and magnifications are those that will be used for near future semiconductor wafers (e.g., pixel counts on the order of about 2000 by about 2000 and pixel sizes of about 50 nm on a side (yielding substantially the same 1 mm field of view as the objective)); and c) efficient collection of the light is best achieved by either a partial elliptical reflector or a condenser lens that delivers the collected radiation to a homogenizer with a “realistic” NA. FIG. 4 illustrates one embodiment of a system configured to provide illumination of a specimen for a process performed on the specimen. The process may include any of the processes described further herein Such as an inspection process, a defect review process, a metrology process, an imaging process (e.g., imaging by photo emission electron microscopy (PEEM), a lithography process, etc.). In this manner, in some embodiments, the LSP lamp is configured for use in wafer inspection. FIG. 4 also illustrates one embodiment of a system (e.g., an inspection system) configured to determine one or more characteristics of a specimen that includes an LSP lamp configured as described herein. As shown in FIG. 4, the system includes laser 48 configured to generate excitation light. Laser 48 may include any of the lasers described herein. The laser is configured to direct the excitation light (or “pump” light) to focusing optics 50. Focusing optics 50 may include a set of focusing or beam conditioning optics. Focusing optics 50 may include any suitable such optics. In addition, although focusing optics 50 are shown in FIG. 4 as including one refractive optical element, focusing optics 50 may include one or more refractive optical elements and/or one or more reflective optical elements. Focusing optics 50 may be further configured as described herein. As shown in FIG. 4, focusing optics 50 are configured to focus the excitation light generated by laser 48 to a plasma (not shown in FIG. 4) in electrodeless lamp 52 (e.g., a relatively high pressure LSP light source) such that the plasma generates light. The plasma and the electrodeless lamp may be configured according to any of the embodiments described herein. The system shown in FIG. 4 is also configured such that the light generated by the plasma illuminates the specimen during the process. For example, the system includes an illumination subsystem configured to illuminate the specimen during the process with the light generated by the plasma. For example, light generated by the plasma that exits electrodeless lamp 52 is collected by optics 54 of the illumination subsystem, which may include “reasonable” NA collection optics 54 (e.g., optics having an NA sufficient to image a substantial portion of the light onto an entrance of homogenizer 56). Optics 54 may include any suitable such optics. In addition, although optics 54 are shown in FIG. 4 as including one refractive optical element, optics 54 may include one or more refractive optical elements and/or one or more refractive optical elements. Optics 54 may be further configured as described herein. The illumination subsystem may also include homogenizer 56. Light from optics 54 is directed to homogenizer 56 as shown in FIG. 4. Homogenizer 56 may include any suitable homogenizer such as a light pipe. Light exiting homogenizer 56 is directed to collection optics 58 of the illumination subsystem, which are configured to collect light that exits homogenizer 56. Optics 58 may include any suitable such optics. In addition, although optics 58 are shown in FIG. 4 as including one refractive optical element, optics 58 may include one or more refractive optical elements and/or one or more reflective optical elements. Optics 58 may be further configured as described herein. As shown in FIG. 4, optics 58 are configured to direct light from homogenizer 56 to beam splitter 60 of the illumination subsystem. Beam splitter 60 may include any suitable optical element such as a 50-50 beam splitter. The illumination subsystem may also include objective 62 such as an inspection microscope objective, which as shown in FIG. 4 may include a number of refractive optical elements. The refractive optical elements included in the objective may have any suitable configuration. Objective 62 may also include one or more refractive optical elements and/or one or more reflective optical elements. Objective 62 is configured to focus light from beam splitter 60 to specimen 64, which may include any of the specimens described herein. For example, specimen 64 may include a wafer, a patterned wafer, or a reticle. The system shown in FIG. 4 also includes a detection subsystem configured to generate output responsive to light from the specimen due to illumination of the specimen. The output can be used to determine the one or more characteristics of the specimen. For example, the detection subsystem may include objective 62, beam splitter 60, imaging or focusing optics 66, and detector or sensor 68. Light from the specimen (e.g., reflected light, scattered light, diffracted light, or some combination thereof) is collected by objective 62 and passes through beam splitter 60. Light from the specimen that passes through beam splitter 60 is focused by imaging or focusing optics 66 onto detector or sensor 68. Optics 66 may include any suitable such optics. In addition, although optics 66 are shown in FIG. 4 as including one refractive optical element, optics 66 may include one or more refractive optical elements and/or one or more reflective optical elements. Optics 66 may be further configured as described herein. Detector 68 may include any of the detectors described herein such as a TDI detector or any other suitable detector or sensor known in the art. The embodiment of the system shown in FIG. 4 may be further configured as described herein. For example, the system shown in FIG. 4 may include a processor such as that shown in FIG. 1 that is configured to use the output generated by the detection subsystem of the system shown in FIG. 4 (e.g., output generated by detector 68) to determine the one or more characteristics of the specimen. The one or more characteristics may include any of the characteristics of the specimen described herein. In one embodiment, laser 48 is a cw laser. In addition, laser 48 is preferably a cw laser since it is preferable that electrons be present at all times within the electrodeless lamp to maintain a relatively high density of excited atomic electronic states within the plasma for a relatively low pump threshold and for relatively good coupling of the excitation (or pump) light to the plasma. In another embodiment, the laser includes a diode laser, a diode laser stack, a fiber laser, a fiber coupled diode laser, a carbon dioxide (CO2) laser, an acoustically modulated diode (i.e., an AM modulated diode), or a diode pumped fiber laser. For example, laser 48 may preferably be one of the following types of light sources: a) fiber coupled laser diodes with fiber apertures from about 100 μm to about 200 μm, b) a CO2 laser; or c) a diode pumped fiber laser. In one embodiment, focusing optics 50 include a lens configured to focus the excitation light to a spot size and radiance sufficient to sustain the plasma. In one such embodiment, the lens has an NA of at least about 0.3. For example, focusing optics 50 preferably includes a relatively large NA lens in order to bring the radiation from pump source a), b), or c) described above or any other lasers described herein to a spot size and radiance sufficient to sustain the plasma. In some embodiments, the focusing optics are configured to focus the excitation light to the lamp to initiate the plasma. In another embodiment, the system includes a pulsed light source, an RF coil, a voltage source external to the lamp, or some combination thereof to initiate the plasma. For example, the plasma may be initiated by the laser or, if one chooses, by either an RF coil or an initial gas breakdown of the electrons by an externally applied voltage and current as in a conventional lamp. The pulsed light source, the RF coil, and the voltage source may include any suitable such components known in the art. In one embodiment, a power of the laser is greater than about 100 W. In another embodiment, an optical average cw power of the excitation light is about 100 W to about 1000 W. For example, in order to achieve the desired average power and brightness, the laser, whether the laser is a), b), or c) described above or any other laser described herein is preferably from about 100 W to about 1000 W of optical average cw power. In another embodiment, the system includes an additional laser configured to generate additional excitation light. In one such embodiment, the focusing optics are configured to focus the additional excitation light to the plasma, and a sum of the power of the laser and the additional laser is in a range of about 100 W cw to about 1000 W cw. For example, the excitation light may be delivered from either one or more light sources, and the sum of the power of the light sources may fall in the range from about 100 W cw to about 1000 W cw. In an additional embodiment, the system includes at least one additional laser configured to generate additional excitation light. In one such embodiment, the focusing optics are configured to focus the excitation light and the additional excitation light to the plasma simultaneously such that the excitation light and the additional excitation light overlap within a cylindrical-shaped region within the electrodeless lamp. In one such embodiment, the cylindrical-shaped region has a diameter of about 0.5 mm to about 1 mm and a thickness of about 100 μm to about 200 μm. In this manner, if multiple sources are used, the beams are preferably overlapped within their focus such that the LSP is obtained primarily within a “hockey puck” 3D space of about 1 mm diameter and about 200 μm thickness within the electrodeless lamp, Such 3D hockey puck space can be achieved within the electrodeless lamp by arranging focusing optics 50 such that the laser beams only reach a diameter of about 200 μm or less when they are within about 1 mm of each other or less (e.g., overlapping). In one embodiment, a gas pressure within the electrodeless lamp is about 1 atm to about 50 atm. For example, the pressure of the gas within the lamp is preferably greater than about 1 atm and no more than about 50 atm such that the gas has an emissivity of as near to unity as possible and such that the radiation within the LSP lamp is not reabsorbed by relatively hot gas outside of the “hockey puck” laser excited region. In one embodiment, the illumination subsystem of the system shown in FIG. 4 includes a condenser lens configured to collect the light generated by the plasma. In another embodiment, the illumination subsystem of the system shown in FIG. 4 includes an elliptical reflector configured to collect the light generated by the plasma, and the plasma is located at one focal point of the elliptical reflector. For example, collection optics 54 are preferably configured to collect as much light generated by the plasma as possible and may include, for example, a condenser lens or an ellipse (e.g., an elliptical reflective collector) with tile plasma located at one focus of the ellipse. The diameter of the homogenizer and the NA of collection optics 58 will define the footprint of the LSP at the specimen plane since objective 62 will normally have a substantially high NA (e.g., an NA on the order of about 0.7 to about 0.95). The ratio of the NA of the collection optics and the NA of the objective, therefore, determines the ratio of the ellipse physical dimension to the footprint of the plasma light source at the specimen plane, the ratio being NAcollector/NAobjective. In one embodiment, the light generated by the plasma includes DUV light. In another embodiment, the light generated by the plasma includes broadband light. In an additional embodiment, the light generated by the plasma has a single line spectra. In some embodiments, the light generated by the plasma includes light in a spectral region from about 180 nm to about 450 nm. In additional embodiments, the light generated by the plasma includes light in a spectral region from about 200 nm to about 450 nm. As described above, the light that is generated by the plasma can be controlled and/or selected by selecting the feed material(s) used to generate the plasma. The embodiments described herein may, therefore, be used in a number of applications. For example, besides wafer inspection and defect review, a relatively bright broadband lamp configured as described herein can be used in the following applications. In particular, the lamps described herein may be used for reticle inspection and defect review using broadband light or single line spectra from particular atomic species such as any of the atomic species described herein. In addition, the lamps may be used for broadband optical metrology such as spectral CD measurement systems that use broadband reflectivity to determine array shapes and sizes (e.g., shapes and sizes of an array of patterned features). In another example, the lamps described herein may be used for electron imaging in which electrons are generated by DUV light exposure of a semiconductor surface creating pho-electrons known as PEEM. In addition, by providing relatively intense broadband light down to substantially short wavelengths, an LSPLS described herein may be used to image a selectable set of work functions. For example, one embodiment of a system configured to generate an image of a specimen includes a laser configured to generate excitation light. The system also includes focusing optics configured to focus the excitation light to a plasma in an electrodeless lamp such that the plasma generates light. In addition, the system includes an illumination subsystem configured to illuminate the specimen with the light generated by the plasma. The system further includes a detection subsystem configured to generate output responsive to electrons emitted by the specimen due to illumination of the specimen with the light generated by the plasma. The output includes the image of the specimen. Such a system may be configured as shown in FIG. 4. For example, the laser included in such a system may include laser 48 shown in FIG. 4. Laser 48 may be configured to generate excitation light as described herein. In this embodiment of the system, the laser may include any of the lasers described herein. In addition, the focusing optics included in such a system may include focusing optics 50 shown in FIG. 4. The focusing optics included in such a system may be configured to focus the excitation light to a plasma in an electrodeless lamp (e.g., electrodeless lamp 52) such that the plasma generates light as described further herein. The plasma and the electrodeless lamp included in such a system may be configured as described further herein. In addition, in a system configured for PEEM, the light generated by the plasma may include DUV light. The plasma may generate DUV light as described further herein. In one embodiment, the specimen imaged by such a system may include a surface formed of a semiconductive material. The semiconductive material may include any semiconductive material that will emit electrons in response to illumination with DUV light. In this manner, the system may be used for electron imaging in which electrons are generated by DUV light exposure of a semiconductor surface creating PEEM that are then detected. In another embodiment, the light generated by the plasma includes broadband light such that the system can image a selectable set of work functions of the specimen. A plasma configured to generate broadband light may be configured as described further herein. Therefore, the plasma may be configured to provide relatively intense broadband light down to substantially short wavelengths such that the system can be used to image a selectable set of work functions. Furthermore, the illumination subsystem included in such a system may be configured as shown in FIG. 4. For example, the illumination subsystem may include optics 54, homogenizer 56, collection optics 58, beam splitter 60, and objective 62 configured to illuminate specimen 64 with the light generated by the plasma. The detection subsystem of the imaging system may also be configured as shown in FIG. 4. For example, the detection subsystem may include objective 62, beam splitter 60, imaging or focusing optics 66, and detector 68, and the detection subsystem may be configured to generate output responsive to electrons emitted by specimen 64 due to illumination of specimen 64 with the light generated by the plasma. However, unlike the systems described above, in systems configured to generate an image of the specimen using electrons emitted by the specimen, the elements of the detection subsystem may be configured to collect, focus, and detect electrons emitted by the specimen instead of light from the specimen and may include any such elements known in the art. In yet another example, the lamps described herein may be used in lithography systems configured to employ i-line radiation that are still in use and sold in the semiconductor industry. While existing electrical discharge light sources are larger in size (many mm's) and require higher electrical power (about 5 kW), the makers of these lithography systems (or “litho steppers”) desire higher brightness and longer lifetimes. Even if an LSPLS described herein uses about 1 kW to about 3 kW of IR pump power (i.e., IR laser power), the LSPLS would still have value if the lamp lasted longer and produced more i-line light within the required volume thereby allowing higher stepper throughputs. For example, another embodiment relates to a system configured to perform a lithography process. This system includes a laser configured to generate excitation light. The system also includes focusing optics configured to focus the excitation light to a plasma in an electrodeless lamp such that the plasma generates light. In addition, the system includes an illumination subsystem configured to image the light generated by the plasma onto the specimen in a predetermined pattern such that the predetermined pattern can be transferred to the specimen. Such a system can be configured as shown in FIG. 4. For example, a system configured to perform a lithography process may include laser 48 configured to generate excitation light. The laser may include any of the lasers described herein, and the excitation light may include any of the excitation light described herein. Such a system may also include focusing optics 50 configured to focus the excitation light to a plasma in electrodeless lamp 52 such that the plasma generates light. In one such embodiment, the light generated by the plasma includes i-line light. The plasma and the electrodeless lamp may be further configured as described herein. A system configured to perform the lithography process may also include an illumination subsystem, which may include optics 54, homogenizer 56, collection optics 58, beam splitter 60, and objective 62 configured to illuminate specimen 64 with the light generated by the plasma. In a different embodiment, the illumination subsystem may include optics 54 configured to collect the light generated by the plasma and objective 62 configured to image the light onto specimen 64. In this manner, the lithography system may or may not include homogenizer 56, collection optics 58, and beam splitter 60. Specimen 64 may, in this embodiment, include a wafer or another substrate having a layer of resist formed thereon. The resist may be any resist that is suitable for i-line lithography. In addition, during a lithography process, a reticle (not shown) may be positioned in the path of the light between optics 54 and objective 62 such that the light passes through the reticle in a predetermined pattern such that the predetermined pattern can be imaged onto the specimen. In this manner, a predetermined pattern can be transferred from the reticle to the specimen. The predetermined pattern transferred to the specimen may be approximately the same as the predetermined pattern formed on the reticle (e.g., allowing for effects of the reticle on the light and effects of the resist on the image projected onto the specimen) or approximately the inverse of the predetermined pattern formed on the reticle (e.g., allowing again for effects of the reticle on the light and effects of the resist on the image projected onto the specimen). In other words, the lithography system described herein may be used to transfer a predetermined pattern to a positive resist and/or a negative resist. In one embodiment, the electrodeless lamp is at a pressure of above about 1 atm at a working temperature of the electrodeless lamp, and the light generated by the plasma includes light in a spectral region from about 200 nm to about 400 nm. In this manner, the LSP lamps described herein may be used at pressures above about 1 atm (at their working temperature) for the production of light for applications such as wafer inspection in the spectral region between about 200 nm to about 400 nm (see, for example, G. Babucke, G. Hartel, and H-G Kloss, J. Phys. D, App. Phys, 24, 1316-1321, (1991), which is incorporated by reference as if fully set forth herein) with brightness from about 10 W/mm2-sr to about 50 W/mm2-sr. In another embodiment, the light generated by the plasma has a brightness of about 2 W/mm2-sr to about 50 W/mm2-sr in an integral region of the electromagnetic spectrum from about 200 nm to about 400 nm. In this manner, the electrodeless lamps described herein can be used as sources with spectral brightness in the range from about 2 W/mm2-sr to about 50 W/mm2-sr in the integral region of the electromagnetic spectrum from about 200 nm to about 400 nm. In a further embodiment, the light generated by the plasma has an average power of at least about 3 W within any band in a spectral region from about 200 nm to about 450 nm. In this manner, the LSP lamps described herein may be configured to generate in excess of about 3 W of average power within any band contained within the wavelength region between about 200 nm and about 450 nm. In one embodiment, the plasma does not produce an average plasma opacity over a plasma axis length of greater than about 1 e-folding from one end of the electrodeless lamp to another end of the electrodeless lamp. For example, in some embodiments, one or more relatively high brightness cw lasers or light drivers are configured for excitation of these plasmas in roughly cylindrical geometries in which the plasma axis length does not produce an average plasma opacity over this region of greater than about one e-folding from “end-cap” to “end-cap.” In another embodiment, a wavelength of the excitation light is about 0.7 μm to about 1.5 μm. For example, one or more diode light drivers, one or more diode light driver stacks, one or more fiber light drivers, one or more fiber coupled diode light drivers, one or more other sources of low cost light driven technology, or some combination thereof at wavelengths between about 0.7 μm and about 1.5 μm may be configured to excite the light driven electrodeless produced plasma. In an additional embodiment, one or more CO2 lasers are configured to excite the light driven electrodeless produced plasma. In one embodiment, the electrodeless lamp includes a background rare gas and a gas containing a halide. In one such embodiment, a pressure of the background rare gas is at least about 1 atm, and a pressure of the gas containing the halide is less than or equal to about 1 atm. For example, in some embodiments, the light driven produced plasma of the LSP lamps described herein is configured to produce excimer radiation by using about 1 atm or more of background rare gas along with a similar or lower fill pressure of halide containing gas. In another embodiment, a fill pressure of gases in the electrodeless lamp is about 4 atm or higher. In this manner, the LSP lamps described herein may be configured to use fill pressures of gases to as much as about 4 atm (or bar) to about 10 atm (or bar) or higher (see, for example G. Babucke, G. Hartel, and H-G Kloss, J. Phys. D, App. Phys, 24, 1316-1321, (1991), which is incorporated by reference as if fully set forth herein). In a further embodiment, the electrodeless lamp includes a fill gas, and an opacity of the fill gas at a working temperature and pressure of the electrodeless lamp is less than or equal to about 10% reabsorption of light emitted from a center of the lamp within a spectral region from about 200 nm to about 450 nm. For example, the LSP lamps described herein may be configured to use one or more fill gases selected such that the opacity of the one or more fill gases at the working temperature and pressure of the lamps does not exceed about 10% reabsorption of about 200 nm to about 450 nm radiation emitted from the center of the lamp (see, for example, D. Erskine, B. Roznyal, and M. Ross, J. Quant. Spec. and Radiat. Transfer, 51(12), 97-100 (1994), which is incorporated by reference as if fully set forth herein). In one embodiment, the focusing optics include a lens configured to focus the excitation light to the plasma such that the plasma has a predetermined shape. In one such embodiment, the lens has an NA of at least about 0.3. In some embodiments, an excitation volume of the electrodeless lamp is substantially matched to a field of view of collection optics of a detection subsystem of a system configured to inspect the specimen. In this manner, the plasma excitation in the LSP lamps described herein may be shaped by one or more beams delivered through a substantially fast lens (e.g., a lens having an NA greater than about 0.3) to substantially match the excitation volume to the collection optics field of view appropriate for applications such as wafer and reticle inspection. In a farther embodiment, excitation radiation for the LSP lamps described herein is provided by one or more light drivers to form approximately disc or hockey puck shaped plasmas that are substantially matched to image onto the specimen plane in inspection systems. In some such embodiments, the plasma has a diameter of between about 100 μm and about 2 mm. In addition, the plasma size may affect and/or control the size of the light beam generated by the plasma. For example, in one embodiment, the light generated by the plasma has a diameter of about 100 μm to about 2 mm. In an additional embodiment, light drivers of any wavelength are used to ignite the plasma in the LSP lamps described herein with a light driven power in excess of about 100 W. In another embodiment, light driver radiation in which the light source medium is a diode pumped fiber of moderate M-squared is used for the LSP lamps described herein. In yet another embodiment, light drivers of the LSP lamps described herein are configured for use at wavelengths of about 1 μm or wavelengths between about 700 nm and about 1.3 μm. In one embodiment, the plasma is generated using a rare earth gas and a mercury gas. In one such embodiment, the light generated by the plasma includes light in a spectral region from about 230 nm to about 480 nm. For example, the LSP lamps described herein include electrodeless or light driven produced plasmas that contain a combination of rare earth (Xe, Ar, . . . ) and Hg gases selected to optimize spectral brightness in the wavelength region of about 230 nm to about 480 nm. In another embodiment, the LSP lamps described herein are substantially flat on one side of the LSP lamps such that the LSP lamps have a shape that is generally hemispherical to reduce, and even limit, the distance between the entrance of the light driver to the working medium and its focal point. In a further embodiment, such a configuration of the LSP lamps and other related bulb design concepts are employed to optimize the shape of the plasma to the collector for the inspection system. In one embodiment, a temperature of the plasma is about 10,000 K to about 30,000 K. For example, plasma temperatures of the LSP lamps described herein may be between about 10,000 K to about 30,000 K for any of the fill gases described herein. In another embodiment, specially designed “ignitor” electrodes are used in conjunction with the overall light driven produced plasma bulb. In one such embodiment, the specially designed ignitor electrodes are used with excitation light driver(s) that do not have high enough intensity to initiate the plasma action. In some embodiments, the laser includes a frequency doubled laser, and a wavelength of the excitation light is about 0.4 μm to about 0.7 μm. For example, frequency doubled light drivers in the mid- and near-IR region of the visible spectrum (about 0.4 μm to about 0.7 μm) may be used for excitation of the plasma in the LSP lamps described herein. In one embodiment, the electrodeless lamp includes an internal lens or a curved reflector. For example, the LSP lamps described herein may include an internal lens or curved reflector to achieve substantially high NA focus. In an additional embodiment, the LSP lamps described herein include an electrodeless or light driven produced plasma in which radiation collected from the plasma between about 200 nm to about 450 nm is more than about 3 W. In a further embodiment, relatively high peak power light sources such as amplitude modulation (AM) modulated diodes (or AM modulated diodes) or fiber light sources are used with the LSP lamps described herein to increase the coupling efficiency of the driver to the plasma or lamp working region. Further description provided herein generally relates to IR pump light shaping that may be used for generating an optimal plasma shape for the best coupling with an illumination subsystem. In particular, to optimize the collection of the generated light, the pump light source is preferably shaped to an optimal form. This shape is not necessarily the smallest possible light source size and depends on the illumination subsystem. In one embodiment, an NA of the focusing optics is selected such that a size of the plasma is reduced along a direction to which the excitation light is focused to the plasma by the focusing optics. For example, a system that includes an LSP lamp and that may be configured according to any of the embodiments described herein may be configured to provide relatively high NA illumination (e.g., using either a relatively high NA lens or a relatively high NA partial elliptical reflector) of a specimen for inspection or another application described herein. Relatively high NA illumination of the plasma may be used, not for the reduction of the pumping light beam size, but for achieving the shortest depth of focus to reduce plasma size along the pumping beam. In one embodiment, the laser includes a distributed light source. For example, a distributed light source may be used to excite the plasma in an LSP lamp. One example of a distributed light source is a laser diodes bar. The distributed light source allows the use of a relatively large focus spot together with relatively short focal length. Effectively, the distributed light source can be used to form an image of the desired pupil pattern for illumination of the specimen. For example, illumination for edge contrast (EC) mode inspection may be provided using a ring (“bagel”) plasma shape if the plasma is located in a pupil or image conjugate plane. For a relatively high power pumping laser, this shape can be difficult to achieve unless a distributed light source is used as the excitation light source. In one embodiment, the focusing optics include at least one optical element configured to focus the excitation light to the plasma and configured to collect the light generated by the plasma. For example, one configuration of the system that can be used to provide such shaping includes common optics for light pumping and DUV/UV/Vis generated light collection, and such common optics may include a focusing partial elliptical reflector or parabolic reflector to achieve relatively high NA. Such configurations are described further below. In one embodiment, the focusing optics are configured to focus the excitation light to the plasma in two substantially opposite directions. For example, FIG. 5 illustrates one embodiment of focusing optics configured for shaping the plasma by pumping in the forward and backward directions. As shown in FIG. 5, the focusing optics include beam expander 70 configured to expand beam 72 of light from a light source such as a laser (not shown in FIG. 5). Beam expander 70 may include any suitable optical element known in the art. The light source may include any of the light sources described herein configured to generate any of the excitation light described herein. As shown in FIG. 5, light from beam expander 70 is directed to beam splitter 74, which may include any suitable beam splitter known in the art. For example, beam splitter 74 may include a 50-50 beam splitter. As shown in FIG. 5, beam splitter 74 is configured such that one portion of the light passes through beam splitter 74 and is directed to reflective optical element 76, which may include a flat mirror or another suitable reflective optical element. Light reflected by reflective optical element 76 is directed to reflective optical element 78, which may also include a flat mirror or another suitable reflective optical element. Light reflected by reflective optical element 78 is directed to refractive optical element 80, which may be configured as a focusing lens, and which may include any of the refractive optical elements described herein. Refractive optical element 80 is configured to focus the light from reflective optical element 78 to plasma 82. The plasma may be further configured as described herein. As further shown in FIG. 5, beam splitter 74 is configured such that another portion of the light from beam expander 70 is reflected from beam splitter 74 and is directed to reflective optical element 84, which may include a flat mirror or another suitable reflective optical element. Light reflected by reflective optical element 84 is directed to refractive optical element 86, which may be configured as a focusing lens, and which may include any of the refractive optical elements described herein. Refractive optical element 86 is configured to focus light from reflective optical element 84 to plasma 82. As shown in FIG. 5, light from refractive optical elements 80 and 86 is directed to plasma 82 simultaneously at substantially opposite directions. In this manner, light from refractive optical elements 80 and 86 can pump the plasma in both the forward and backward directions. In addition, light from refractive optical elements 80 and 86 can shape the plasma by pumping the plasma in the forward and backward directions. Furthermore, in some embodiments, refractive optical elements 80 and 86 may be relatively high NA lenses (e.g., such that the relatively high NA excitation light has a relatively short depth of focus along the direction of the pumping beams thereby reducing plasma size along the directions of the pumping beams). The focusing optics shown in FIG. 5 may be further configured as described herein. In addition, the focusing optics shown in FIG. 5 may be included in any of the system embodiments described herein. In another embodiment, the focusing optics include at least one reflective optical element and at least one refractive optical element. In one such embodiment, the at least one reflective optical element and the at least one refractive optical element are configured to focus the excitation light to the plasma simultaneously. For example, FIG. 6 illustrates one embodiment of focusing optics configured for using combined refractive and reflective optics to “double focus” excitation light such as an IR pump beam. As shown in FIG. 6, the focusing optics includes beam expanders 88 and 90 configured to expand the cross-sectional areas of beams 92 and 94, respectively. The beam expanders may include any suitable beam expanders known in the art. Beams 92 and 94 may be generated by any of the excitation light sources described herein. In addition, beams 92 and 94 may be generated by the same excitation light source or different excitation light sources (e.g., the same or different lasers). Light from beam expander 88 is directed to spherical reflector 96. Spherical reflector 96 may include any suitable reflective optical element known in the art and may be further configured as described herein. As shown in FIG. 6, spherical reflector 96 is configured to focus light from beam expander 88 to plasma 98. Plasma 98 may be configured according to any of the embodiments described herein. In a similar manner, light from beam expander 90 is directed to spherical reflector 100. Spherical reflector 100 may include any suitable reflective optical element known in the art and may be further configured as described herein. As shown in FIG. 6, spherical reflector 100 is configured to focus light from beam expander 90 to plasma 98. In some embodiments, the focusing optics are configured to focus the excitation light to the plasma in two substantially perpendicular directions simultaneously. For example, as shown in FIG. 6, spherical reflectors 96 and 100 are configured to focus light to plasma 98 simultaneously at substantially perpendicular directions. The focusing optics shown in FIG. 6 may also include refractive optical element 102 configured to focus light to plasma 98. Refractive optical element 102 may include any of the refractive optical elements described herein. As shown in FIG. 6, refractive optical element 102 and spherical reflector 96 may be configured to focus light to plasma 98 simultaneously at substantially perpendicular directions. In addition, as shown in FIG. 6, refractive optical element 102 and spherical reflector 100 may be configured to focus light to plasma 98 simultaneously at substantially opposite directions. In one embodiment, the focusing optics are configured to focus the excitation light to the plasma at different directions simultaneously to substantially the same focal spot. In another embodiment, the focusing optics are configured to focus the excitation light to the plasma at different directions simultaneously to offset focal spots. For example, two or more of the pump assemblies shown in FIG. 6 can be combined at substantially the same focal spot or slightly offset focal points to achieve desired plasma shaping. The focusing optics shown in FIG. 6 may be further configured as described herein. In addition, the focusing optics shown in FIG. 6 may be included in any of the system embodiments described herein. In one embodiment, the focusing optics are configured to collect the excitation light that is not absorbed by the plasma and to focus the collected excitation light to the plasma. For example, FIG. 7 illustrates one embodiment of focusing optics for “re-pumping” 3 or more passes of the pump light into the plasma. The focusing optics shown in FIG. 7 include refractive optical elements 104 and 106. Refractive optical elements 104 and 106 are configured to focus excitation light from one or more excitation light sources (not shown in FIG. 7), which may include any of the excitation light sources described herein, to a plasma (not shown in FIG. 7), which may be configured as described herein. Refractive optical elements 104 and 106 may be further configured as described herein (e.g., refractive optical elements 104 and 106 may include relatively high NA lenses). At least some of the excitation light focused to the plasma by refractive optical elements 104 and 106 is preferably absorbed by the plasma, and some of the excitation light focused to the plasma by refractive optical elements 104 and 106 may not be absorbed by the plasma and will, therefore, transmit through the plasma. The focusing optics may also include reflective optical elements 108, 110, 112, and 114. Excitation light focused to the plasma by refractive optical element 104 that transmits through the plasma may be collected by reflective optical element 108, which may be a flat mirror or any other suitable reflective optical element. Excitation light collected by reflective optical element 108 is directed to reflective optical element 110, which is configured to direct the excitation light from reflective optical element 108 back to the plasma. Reflective optical element 110 may also include a flat mirror or any other suitable reflective optical element. In this manner, excitation light that was initially not absorbed by the plasma may be “re-pumped” back into the plasma, which may increase the efficiency of the LSP light source. In a similar manner, excitation light focused to the plasma by refractive optical element 106 that transmits through the plasma may be collected by reflective optical element 112, which may be a flat mirror or any other suitable reflective optical element. Excitation light collected by reflective optical element 112 is directed to reflective optical element 114, which is configured to direct the excitation light from reflective optical element 112 back to the plasma. Reflective optical element 114 may also include a flat mirror or any other suitable reflective optical element. In this manner, excitation light that was initially not absorbed by the plasma may be “re-pumped” back into the plasma, which may increase the efficiency of the LSP light source. The angle, a, at which the refractive optical elements shown in FIG. 7 focus excitation light to the plasma may or may not be the same as angle, b, at which the excitation light is re-pumped back into the plasma by the reflective optical elements shown in FIG. 7. The focusing optics shown in FIG. 7 may be further configured as described herein. In addition, the focusing optics shown in FIG. 7 may be included in any of the system embodiments described herein. In one embodiment, the system includes a gas flow subsystem configured to direct a gas to the plasma. For example, a system configured to provide illumination as described herein may include a gas flow subsystem (or “jet system”) for sustained arc shaping. FIGS. 8-9 illustrate various embodiments of a gas flow subsystem that is configured for sustained arc shaping. As shown in FIG. 8, one embodiment of a system that includes a gas flow subsystem may also include focusing optics which include refractive optical element 116 configured to focus excitation beam 118 from an excitation source (not shown in FIG. 8) to plasma 120. Refractive optical element 116 may be configured as described further herein (e.g., refractive optical element 116 may include a relatively high NA refractive optical element). In addition, refractive optical element 116 may be replaced with one or more refractive optical elements and or one or more reflective optical elements. The excitation source may include any of the excitation sources described herein. Excitation beam 118 may include, for example, an electron beam, an X-ray beam, a particle beam, or a laser beam. Plasma 120 may be further configured as described herein. As further shown in FIG. 8, the gas flow subsystem includes nozzle 122 that may be coupled to one or more gas sources (not shown in FIG. 8). Nozzle 122 may be coupled to any suitable gas source(s). Nozzle 122 may have any suitable configuration such that gas jet 124 can be directed to plasma 120. In addition, nozzle 122 may be further configured as described herein. In one embodiment, the gas flow subsystem is configured to direct the gas to the plasma such that the gas directed to the plasma affects a shape of the plasma. For example, the gas jet may be directed to plasma 120 such that the gas jet assists in shaping the plasma and therefore can be used for sustained arc shaping. In one embodiment, the gas flow subsystem is configured to direct a gas to the plasma at a direction substantially opposite to a direction at which the focusing optics focus the excitation light to the plasma. For example, as shown in FIG. 8, gas jet 124 may be directed to the plasma along a direction that is substantially opposite to the direction along which the excitation beam is directed to the plasma by refractive optical element 116. However, the gas jet may be directed to the plasma along a direction arranged at a different angle with respect to the direction along which the excitation beam is directed to the plasma. For example, in one embodiment, the gas flow subsystem is configured to direct a gas to the plasma at a direction substantially perpendicular to a direction at which the focusing optics focus the excitation light to the plasma. In one such example, as shown in FIG. 9, gas jet 124 is directed to plasma 120 along a direction that is substantially perpendicular to the direction along which excitation beam 118 is directed to the plasma by refractive optical element 116. The embodiment shown in FIG. 9 may be further configured as described above with respect to FIG. 8. In addition, the embodiments shown in FIGS. 8 and 9 may be further configured as described herein. Furthermore, the embodiments shown in FIGS. 8 and 9 may be included in any of the systems described further herein. In one embodiment, the gas flow subsystem is configured to direct a gas to the plasma such that the gas directed to the plasma increases isolation of the plasma. For example, some embodiments of the system may be configured to use target shaping (localization in space) by the gas flow subsystem instead of or in addition to the excitation light shaping or pumping beam shaping to obtain a predetermined light source shape and for the light source isolation. Since the considered target (i.e., the plasma) in most cases is either a gas or liquid medium, using a gas jet is a natural shaping technique for such media. Two main configurations can be used to overcome the pumping beam resolution limitation and avoid pumping beam and/or generated light scattering and/or absorption by the cold gas (i.e., the gas jet). One embodiment includes light pumping substantially opposite to the gas jet stream (e.g., as shown in FIG. 8). In this case, the plasma size may be limited by the gas jet size in two directions and by diffusion in the third direction. (The pumping beam spot size in this case can be reduced down to a few microns.) Another embodiment includes passing a gas jet through an RF standing wave knot (a gas jet directed substantially perpendicular to the wave front). The RF wave front is preferably relatively wide, and the gas jet may limit the plasma size. An additional embodiment includes an excitation beam such as an ion or electron beam directed substantially perpendicular to the gas jet stream (e.g., as shown in FIG. 9). Such an embodiment may be used to deliver the pumping beam relatively un-scattered to the desired location in the plasma. In another embodiment, the gas flow subsystem is configured to direct a gas to the plasma such that the gas increases propagation of the generated light through the plasma. For example, a further embodiment uses Hg in an electrodeless lamp for the light generation. Cold Hg vapor in the electrodeless lamp effectively absorbs substantially all of the light at a wavelength of about 250 nm. The use of a gas jet reduces, and may even avoid, propagation of the generated light through the cold Hg vapor. Similar effects can be observed for various targets. FIGS. 10-11 illustrate various embodiments of a nozzle design that may be used in gas flow subsystems configured to direct a gas to a plasma in an electrodeless lamp that generates DUV light. As shown in FIG. 10, excitation light 126 from an excitation source (not shown in FIG. 10) may be directed through cold mirror 128 (e.g., a dichroic mirror configured to reflect substantially the entire visible and ultraviolet light spectrum and to transmit infrared wavelengths). The excitation light may include any of the excitation light described herein such as a laser beam, which may be expanded as described herein. In addition, the excitation source may include any of the excitation sources described herein. Excitation light 126 that passes through cold mirror 128 is directed toward focusing optics that include reflective optical element 130, which is configured to focus the excitation light that passed through the cold mirror to plasma 132. Reflective optical element 130 may include a spherical mirror, an elliptical mirror, or any other suitable reflective optical element, all of which may be further configured as described herein. Plasma 132 may be further configured as described herein. In one embodiment, the gas flow subsystem is configured to direct a gas to the plasma through an aperture in an optical element of the focusing optics. For example, as shown in FIG. 10, reflective optical element 130 may include aperture 134 configured such that nozzle 136 and/or gas jet 138 can pass through the aperture. In this manner, nozzle 136 may be configured to direct gas jet 138 through reflective optical element 130 to plasma 132. Nozzle 136 may be further configured as described herein. The gas jet may also be further configured as described herein. Light 140 generated by plasma 132 such as DUV light and/or any other light described herein may be directed by cold mirror 128 to other optical components (not shown in FIG. 10), which may include any of the optical components of any of the illumination subsystems described herein, such that the light can be directed to a specimen (not shown in FIG. 10), which may include any of the specimens described herein, for imaging applications or any other applications described herein. The embodiment shown in FIG. 10 may be further configured as described herein. In addition, the embodiment shown in FIG. 10 may be included in any of the systems described herein. As shown in FIG. 11, excitation beam 142 from an excitation source (not shown in FIG. 11), which may include an electron beam, an X-ray beam, a particle beam, a laser beam, or any other excitation radiation, is directed to focusing optics that include refractive optical element 144. Refractive optical element 144 may be further configured as described herein. For example, the refractive optical element may include one or more lenses that are configured to focus the excitation beam to plasma 146. As further shown in FIG. 11, the focusing optics may also include reflective optical element 148. A portion of the excitation beam that passes through plasma 146 may be collected by reflective optical element 148, which may be configured to focus the portion of the excitation beam that passed through the plasma back to the plasma. Reflective optical element 148 may include a spherical mirror, an elliptical mirror, or any other suitable reflective optical element, all of which may be further configured as described herein. Reflective optical element 148 may include aperture 150 configured such that nozzle 152 and/or gas jet 154 can pass through the aperture. In this manner, nozzle 152 may be configured to direct gas jet 154 through reflective optical element 148 to plasma 146. Nozzle 152 may be further configured as described herein. The gas jet may also be further configured as described herein. Light (not shown in FIG. 11) generated by plasma 146 such as DUV light and/or any other light described herein may be collected and directed to other optical components (not shown in FIG. 11), which may include any of the optical components of any of the illumination subsystems described herein, such that the light can be directed to a specimen (not shown in FIG. 11), which may include any of the specimens described herein, for imaging applications or any other applications described herein. The embodiment shown in FIG. 11 may be further configured as described herein. In addition, the embodiment shown in FIG. 11 may be included in any of the systems described herein. Jet-based pumped plasmas have a number of features. For example, in one embodiment, the gas flow subsystem is configured to direct a gas to the plasma through a sonic or supersonic nozzle to reduce a volume of the plasma and to reduce absorption of the generated light by the gas. In one such example, a supersonic nozzle can be used for relatively high pressure or vacuum conditions. One benefit of such a configuration is that target gas or liquid density is relatively high at the jet and relatively low outside thereby limiting the light emitting volume and limiting self absorption of UV light by “cold gas.” In another embodiment, the gas flow system includes a cylindrical-shaped nozzle. In an additional embodiment, the gas directed to the plasma increases uniformity of a density profile of the plasma. For example, another feature of a jet-based pumped plasma is that a cylindrical nozzle design can be optimized to generate a substantially uniform density profile for laser excited plasmas. In a further embodiment, the gas directed to the plasma creates an interaction media having a density suitable for interactions between the excitation light and the plasma. For example, an additional feature of a jet-based pumped plasma is that gas jets can be used to create a suitable density interaction media for laser plasma interactions. In some embodiments, the focusing optics are configured to direct the excitation light to one or more edges of the gas jet thereby affecting a shape of the gas jet. For example, a further feature of a jet-based pumped plasma is that a laser pulse can be focused with a spherical or axial lens onto the edge of the gas jet to generate a preformed shape. (See, for example, V. Malka et al., “Channel Formation in Long Laser Pulse Interaction with a Helium Gas Jet” Phys. Rev. Lett. 16, 2979, 1997, which discloses that plasma expansion is governed by a thermal wave during the laser pulse; K. Krushelnick, A. Ting, C. I. Moore, H. R. Burris, E. Esarey, P. Sprangle, and M. Baine, “Plasma Channel Formation and Guiding during High Intensity Short Pulse Laser Plasma Experiments” Phys. Rev. Lett. 78, 4047, 1997; and S. P. Nikitin, T. M. Antonsen, T. R. Clark, Y. Li, and H. M. Milcherg, “Guiding of intense femtosecond pulses in preformed plasma channels,” Opt. Lett. 22, 1787, 1997, each of which is incorporated by reference as if fully set forth herein.) In another embodiment, a pressure of the gas directed to the plasma is selected based on one or more predetermined characteristics of the plasma. For example, yet another feature of a jet-based pumped plasma is that controlling the gas flow using a sonic or a supersonic nozzle is preferable to provide the desired interaction plasma density profile. When creating a plasma using a gas jet, the desired density can be reached by varying or choosing the initial gas pressure. An additional feature of a jet-based pumped plasma is that changing the gas pressure can vary the initial neutral density. In an additional embodiment, the gas flow subsystem includes a nozzle through which the gas is directed to the plasma, and a diameter of the nozzle is selected based on one or more predetermined characteristics of the plasma. For example, a further feature of a jet-based pumped plasma is that changing the nozzle diameter can change the plasma length. In one embodiment, the system is configured to apply an external magnetic field to the plasma to alter one or more characteristics of the plasma. For example, the system may use a magnetic field for pumping light absorption optimization and for plasma shaping. Many of the papers written about LSPLS suggest that IR absorption is mediated by free electrons in the plasma. IR absorption drops significantly as light frequency falls below the plasma frequency. Introduction of a magnetic field would change electron plasma frequency and respectively change the absorption. The target absorption can be adjusted to be higher or lower by adjusting the magnetic field. In addition, the IR absorption coefficient is proportional to the squared ratio of the pumping light frequency to plasma frequency. Therefore, the magnetic field effectively changes plasma frequency. Furthermore, if light absorption and light generation in the UV are dominated by atomic orbital transitions of charged or neutral plasma species, relatively high magnetic fields (e.g., greater than about 3000 Gauss) can be used to broaden the generated light thereby resulting in less self-absorbed radiation. In some embodiments, an external magnetic field is used for plasma shaping. In such embodiments, one or more magnetic fields may be used to confine and modify the location of the energetic plasma electrons and hence the light emitting region. Such confining and modifying of the location of the energetic plasma electrons can be performed by changing the diffusion parameters, using magnetic wigglers, magnetic bottles, magnetic mirrors, shaping using wiggler magnet arrays (1D, 2D, or 3D), and the use of an external magnetic field to accelerate electrons like that in the undulator of a flee-electron laser for relatively strong focusing of electron trajectories. In another embodiment, the system includes a gas flow subsystem configured to direct one or more feed materials to the plasma after generation of the plasma. For example, forced gas flow may be used in the electrodeless lamp. Forced gas flow in the electrodeless lamp is similar to the use of a gas jet for the plasma shaping, and forced gas flow can be used in combination with one or more gas jets for the plasma shaping. Forced gas flow can be used to generate a non-equilibrium plasma (e.g., to effectively reduce relaxation time or to reduce pumped gas temperature). For example, forced gas flow can be used for H2 and D2 pumping. In this case, the continuum UV irradiation is formed by the excited molecules and followed by dissociation of these molecules. The forced gas flow will deliver new molecules to be excited in the plasma zone. In a further embodiment, ignition methods that can be used to initiate the plasma include light pulse, electrical, RF, or some combination thereof. For example, as described above, the system may include a pulsed light source, an RF coil, a voltage source external to the lamp, or some combination thereof configured to initiate the plasma. In an additional embodiment, relatively high purity oases are used. As used herein, the term “relatively high purity gases” generally refers to gases with levels of impurities about 3 orders of magnitude lower than the usual levels of impurities in gases used in discharge lamp applications. Relatively high purity gases may be used for contamination protection since even relatively low levels of impurities can significantly affect windows and surfaces of other optical elements. In addition, relatively high purity gases may be used for efficiency optimization since the level(s) of impurities can affect the temperature in the plasma, especially electron temperature. Using relatively high purity gases may also include adding relatively small controlled amounts of impurities (e.g., oxygen) to the gases. In one embodiment, the system includes a cleaning subsystem configured to remove photocontamination from one or more optical elements of the focusing optics, one or more optical elements of the system, or some combination thereof. For example, the embodiments described herein may be configured for photocontamination control and purged optics (e.g., of both UV and IR components). For example, both UV and pumping IR light may cause significant photocontamination. A photocontamination control environment is preferable for all (UV and IR) optics. The photocontamination control environment may be created using optics purging and providing a substantially exactly dosed amount of ozone for the cleaning. Ozone can be generated by either UV light generated by the plasma or by special ozone generation. Some oxygen can be added to the target gas as well. In one embodiment, the plasma is generated from one or more feed materials that include a liquid. For example, the embodiments described herein may also be configured for the use of liquid targets. An important characteristic of the target is the density of the atoms (or ions). The use of a liquid target allows increases in, and even maximization, of the plasma density. In order to form a plasma and to transfer generated light from the plasma area, a jet configuration is preferably used. Further description provided herein generally relates to excitation light (e.g., IR beam) delivery configurations. In one embodiment, the system includes an illumination subsystem configured to illuminate the specimen during the process with the light generated by the plasma. In one such embodiment, the illumination subsystem includes a reflective optical element configured to collect the light generated by the plasma and to direct the collected light to one or more refractive optical elements of the illumination subsystem. For example, FIGS. 12 and 13 illustrate the mapping of light coupling in a (refractive) illumination subsystem used in the 2367 system that is commercially available from KLA-Tencor. As shown in FIG. 12, the illumination subsystem may include reflective optical element 158 configured to collect the light generated by plasma 156 and to direct the collected light to one or more refractive optical elements (e.g., condenser lens 162) of the illumination subsystem. In particular, as shown in FIG. 12, light from plasma 156, which may be configured according to any of the embodiments described herein, is collected by reflective optical element 158. Reflective optical element 158 may be a spherical mirror, an elliptical mirror, or any other suitable reflective optical element, and may be further configured as described herein. Light collected by reflective optical element 158 is focused through plasma 156 and this light along with other light from the plasma is directed in the z direction shown in FIG. 12. The light from the plasma may include UV light and/or any other light described herein. The system may also include filter 160 through which the light from plasma 156 and reflective optical element 158 may pass. Filter 160 may include any suitable filter such as a spectral filter. The illumination subsystem may also include condenser lens 162, which as shown in FIG. 12 includes a number of refractive optical elements, which may include any suitable refractive optical elements known in the art. Light that passes through filter 160 may be directed to condenser lens 162, which is configured to direct the light to reflective optical element 164. Reflective optical element 164 may be a flat mirror or any other suitable reflective optical element known in the art. Reflective optical element 164 is configured to direct the light to reflective optical element 166, which may also be a flat mirror or any other suitable reflective optical element known in the art. Reflective optical element 166 is configured to direct the light to refractive optical element 168, which is configured to focus the light to source plane 170 positioned at or proximate to the entrance of homogenizer 172, which may be configured as described herein. Light 174 exiting homogenizer 172 may be directed to additional optical components of the illumination subsystem such that the light can be directed onto a specimen such as any of the specimens described herein. The embodiment shown in FIG. 12 may be included in any of the systems described herein. In addition, the embodiment shown in FIG. 12 may be further configured as described herein. Simulation of the 2367 illumination subsystem shows that 90% of light can be coupled into the homogenizer if the plasma and its image from the backing mirror (reflective optical element 158) are contained within an area of about 3.8 mm×about 0.7 mm. For example, as shown in FIG. 13, plot 176 shows illuminance as a function of x and y positions within the source plane shown in FIG. 12. Plot 176 shown in FIG. 13 illustrates area 178 of the source plane with 90% light coupling into the homogenizer shown in FIG. 12. The goal is to “mold” the plasma inside such a region if possible via laser pumping or other means such as a magnetic field. FIG. 14 illustrates the mapping of light coupling in an (elliptical reflective) illumination subsystem of one system that is commercially available from KLA-Tencor. In particular, FIG. 14 illustrates mapping of η(y, z) from a substantially uniform plasma source having a size of about 2 mm×about 2 mm. As shown in FIG. 14, LSP light source 180 may include plasma 182 disposed within lamp 184. Plasma 182 and lamp 184 may be further configured according to any of the embodiments described herein. Anode 186 and cathode 188 are also disposed within lamp 184. Anode 186 and cathode 188 may be further configured as described herein and may have any other suitable configuration. As shown in exploded view of portion 190 of LSP light source 180, gap 192 of about 2 mm may be between anode 186 and cathode 188, and plasma 182 may be disposed in gap 192. Therefore, the plasma source may have a size of about 2 mm by about 2 mm as described above. Plots 194 and 196 shown in FIG. 14 show the illuminance as a function of position in the y and z directions, and light from the plasma (e.g., UV light) is directed along direction 198 in the z direction. As shown in plot 194, area 200 is an area of reasonably good light coupling into the illumination subsystem. Area 200 has dimensions of about 0.6 mm×about 0.5 mm. In one embodiment, the focusing optics include a reflective optical element configured to focus the excitation light to the plasma, and the excitation light includes an expanded laser beam. For example, FIG. 15 illustrates one embodiment of a simple approach based on the 2367 illumination subsystem design using one focusing mirror. The simplest way to focus an expanded laser beam to the lamp is to use a reflective mirror. For example, as shown in FIG. 15, the focusing optics include reflective optical element 202 configured to focus expanded laser beam 204 to plasma 206. Reflective optical element 202 may include any of the reflective optical elements described herein (e.g., a spherical mirror, an elliptical mirror, etc.). Expanded laser beam 204 may include any of the excitation light described herein produced by any of the lasers described herein. For example, expanded laser beam 204 may include an IR beam. Plasma 206 may be configured according to any of the embodiments described herein. The maximum NA for such focusing optics (e.g., the maximum NA at which light is directed to plasma 206) may be about 0.5. which may be limited by space. In the system shown in FIG. 15, the returned beam may not be recycled. For example, light 208 that passes through plasma 206 may not be recycled back to the plasma. Such a configuration may be suitable, for example, if plasma absorption is relatively strong such that there is no need to recycle the excitation light. The portion of the illumination subsystem shown in FIG. 15 includes reflective optical element 210, filter 213, and condenser lens 214. As further shown in FIG. 15, light emitted by plasma 206 (e.g., UV light) may be collected by reflective optical element 210, which may be configured as described herein. For example, reflective optical element 210 may be a spherical mirror, an elliptical mirror, etc. and may function as a backing mirror for the plasma. Light from the plasma collected by reflective optical element 210 and light emitted from plasma in direction 212 may be directed to filter 213, which may include any suitable filter such as a spectral filter configured to alter the wavelength(s) of the light from the plasma that illuminate the specimen (not shown in FIG. 15). Light that exits filter 213 is directed to condenser lens 214, which includes a set of refractive optical elements as shown in FIG. 15. Condenser lens 214 and the refractive optical elements included in the condenser lens may be further configured as described herein. The embodiment shown in FIG. 15 may be further configured as described herein. In addition, the embodiment shown in FIG. 15 may be included in any of the system embodiments described herein. FIG. 16 illustrates one embodiment of focusing optics that include a focusing lens/mirror combination. If plasma absorption is not strong, it may be desirable to double pass the excitation light (e g., an IR beam) through the plasma with a lens-mirror combination. For example, as shown in FIG. 16, the focusing optics may include refractive optical element 216. Refractive optical element 216 is configured to focus excitation light 218 to plasma 220. Refractive optical element 216 may be further configured as described herein. Excitation light 218 may include any of the excitation light described herein (e.g., an IR beam) and may be generated by any of the lasers described herein. The focusing optics also include reflective optical element 222. Excitation light focused to plasma 220 by refractive optical element 216 that is not absorbed by the plasma may be collected by reflective optical element 222, which may include any of the reflective optical elements described herein (e.g., a spherical mirror, an elliptical mirror, etc.). Reflective optical element 222 may be configured to collect the excitation light that was not absorbed by the plasma and to focus the collected light back to plasma 220. Therefore, the focusing optics shown in FIG. 16 are configured to pass the excitation light through the plasma twice using the combination of refractive optical element 216 and reflective optical element 222. The maximum NA at which the excitation light may be directed to the plasma by the focusing optics shown in FIG. 16 may be about 0.5, which may be limited by space. The portion of the illumination subsystem shown in FIG. 16 includes reflective optical element 224, filter 227, and condenser lens 228. As further shown in FIG. 16, light generated by plasma 220 (e.g., UV light) may be collected by reflective optical element 224, which may be configured as described herein. For example, reflective optical element 224 may be a spherical mirror, an elliptical mirror, etc. and may function as a backing mirror for the plasma. Light generated by the plasma collected by reflective optical element 224 and light generated by the plasma in direction 226 may be directed to filter 227, which may include any suitable filter such as a spectral filter configured to alter the wavelength(s) of the light generated by the plasma that are directed to other optical elements of the illumination subsystem. Light that exits filter 227 is directed to condenser lens 228, which includes a set of refractive optical elements as shown in FIG. 16. Condenser lens 228 and the refractive optical elements included in the condenser lens may be further configured as described herein. The embodiment shown in FIG. 16 may be further configured as described herein. In addition, the embodiment shown in FIG. 16 may be included in any of the system embodiments described herein. In one embodiment, the focusing optics are configured to focus the excitation light to the plasma at different directions simultaneously. For example, FIG. 17 illustrates one embodiment of focusing optics configured for cross-beam pumping that can be used with the condenser lens described above. As shown in FIG. 17, the focusing optics may include refractive optical elements 230 and 232, which are configured to focus excitation light 234 and 236, respectively, to plasma 238. Refractive optical elements 230 and 232 may be further configured as described herein. Excitation light 234 and 236 may include any of the excitation light described herein such as IR beams. In addition, the excitation light may be generated by the same laser (e.g., by a single laser configured to direct excitation light to a beam splitter coupled to appropriate light directing components) or by different lasers (e.g., by different lasers each of which is configured to direct light to one of refractive optical elements 230 and 232). As shown in FIG. 17, refractive optical elements 230 and 232 are configured to direct the excitation light to the plasma simultaneously such that the paths of the excitation light from the two refractive optical elements cross in the space at or near the plasma (hence the terms “cross-beam pumping” and “cross-illumination”). The focusing optics may also include reflective optical elements 240 and 242. Excitation light focused to plasma 238 by refractive optical element 230 that is not absorbed by the plasma may be collected by reflective optical element 240, which may include any of the reflective optical elements described herein (e.g., a spherical mirror, an elliptical mirror, etc.). Reflective optical element 240 may be configured to collect the excitation light that was not absorbed by the plasma and to focus that light back to plasma 238. Therefore, the focusing optics shown in FIG. 17 are configured to pass excitation light 234 through the plasma twice using the combination of refractive optical element 230 and reflective optical element 240. In a similar manner, excitation light focused to plasma 238 by refractive optical element 232 that is not absorbed by the plasma may be collected by reflective optical element 242, which may include any of the reflective optical elements described herein (e.g., a spherical mirror, an elliptical mirror, etc.). Reflective optical element 242 may be configured to collect the excitation light that was not absorbed by the plasma and to focus that light back to plasma 238. Therefore, the focusing optics shown in FIG. 17 are configured to pass excitation light 236 through the plasma twice using the combination of refractive optical element 232 and reflective optical element 242. As shown in FIG. 17, refractive optical elements 230 and 232 are configured to focus the excitation light to the plasma such that the paths of the excitation light from the two refractive optical elements cross in the space at or near the plasma, and reflective optical elements 240 and 242 are also configured to focus the excitation light collected by the reflective optical elements such that the paths of the excitation light from the two reflective optical elements cross in the space at or near the plasma. Therefore, both the excitation light beams and the recycled excitation light beams may be focused to the plasma for cross-beam pumping or cross-illumination. It is possible to create a more favorable plasma shape with cross-beam illumination such as that shown in FIG. 17. The combination of refractive optical element 230 and reflective optical element 240 and the combination of refractive optical element 232 and reflective optical element 242 (e.g., condenser/mirror pairs) can be configured to have substantially the same or different focal points depending on whether it is desired to have a smaller, brighter plasma volume (e.g., which can be created with substantially the same focal points) or a bigger, shaped plasma volume (e.g., which can be created with different focal points). The portion of the illumination subsystem shown in FIG. 17 includes reflective optical element 244, filter 247, and condenser lens 248. As further shown in FIG. 17, light generated by plasma 238 (e.g., UV light) may be collected by reflective optical element 244, which may be configured as described herein. For example, reflective optical element 244 may be a spherical mirror, an elliptical mirror, etc. and may function as a backing mirror for the plasma. Light generated by the plasma collected by reflective optical element 244 and light generated by the plasma in direction 246 may be directed to filter 247, which may include any suitable filter such as a spectral filter configured to alter the wavelength(s) of the light generated by the plasma that are directed to other optical elements of the illumination subsystem. Light that exits filter 247 is directed to condenser lens 248, which includes a set of refractive optical elements as shown in FIG. 17. Condenser lens 248 and the refractive optical elements included in the condenser lens may be further configured as described herein. The embodiment shown in FIG. 17 may be further configured as described herein. In addition, the embodiment shown in FIG. 17 may be included in any of the system embodiments described herein. In one embodiment, the system includes an illumination subsystem configured to illuminate the specimen during the process with the light generated by the plasma. In one such embodiment, the illumination subsystem includes one or more refractive optical elements configured to focus the excitation light to the plasma. For example, FIG. 18 illustrates one embodiment in which a pump beam is directed along the optical axis of the illumination subsystem configuration described above. This configuration may be used if the far-field radiation pattern of the laser-induced plasma is much higher along the pump direction. For example, as shown in FIG. 18, the illumination subsystem may include condenser lens 250, which may be configured as described herein. Excitation light 252 is directed from a laser (not shown in FIG. 18) and/or by one or more optical components such as those described herein through dichroic mirror 254 to condenser lens 250. Excitation light 252 may include any of the excitation light described herein such as IR light, and the laser may include any of the lasers described herein. The dichroic mirror may include any optical component that is substantially transparent to the excitation light (e.g., IR light) and reflects the light generated by the plasma (e.g., UV light). As further shown in FIG. 18, the excitation light passes through condenser lens 250, and if the system includes filter 256, the excitation light that exits the condenser lens passes through the filter. The condenser lens focuses the excitation light to plasma 258. In this manner, the condenser lens of the illumination subsystem is configured to focus the excitation light to the plasma. In another such embodiment, a matching lens (not shown in FIG. 18) may be used to focus the excitation light (e.g., IR light) through the condenser lens. In a further embodiment, the coating currently used in the illumination subsystem may be re-designed (e.g., such that the excitation light can be focused by the condenser lens to the plasma). Furthermore, the illumination subsystem may be designed based on possible laser damage of the components of the illumination subsystem (e.g., to reduce and even prevent damage of the condenser lens by the excitation light). Plasma 258 may be configured according to any of the embodiments described herein. If a portion of the excitation light passes through the plasma (is not absorbed by the plasma), that portion of the excitation light may be collected by reflective optical element 260, which may include any of the reflective optical elements described herein (e.g., a spherical mirror, an elliptical mirror, etc.) and may be further configured as described herein. The portion of the excitation light that is collected by reflective optical element 260 may be focused by the reflective optical element to plasma 258. In one such embodiment, the NA at which the excitation light is focused to the plasma may be about 0.65. Light (e.g., UV light and/or any other light described herein) that is generated by plasma 258 may be collected by reflective optical element 260 and condenser lens 250. Reflective optical element 260 and condenser lens 250 may be configured to direct the light generated by the plasma along direction 262. The light that is generated by plasma 258 and directed along direction 262 may be reflected by dichroic mirror 254 to reflective optical element 264, which may include any suitable reflective optical element known in the art such as a flat mirror. Light from dichroic mirror 254 is reflected by reflective optical element 264 such that the light is directed to refractive optical element 266, which may include any refractive optical element (e.g., a focusing lens) described herein and may be further configured as described herein. Refractive optical element 266 is configured to focus the light to the entrance of homogenizer 268, which may include any of the homogenizers described herein (e.g., a light pipe) and may be further configured as described herein. The embodiment shown in FIG. 18 may be further configured as described herein. In addition, the embodiment shown in FIG. 18 may be included in any of the system embodiments described herein. FIG. 19 illustrates one embodiment of a lens group that can be used to couple excitation light (e.g., IR light) to a plasma (and therefore a LSP light source or lamp) through the condenser lens described above. For example, coupling lens group 270 may be configured to couple light from laser 272, which may include any of the lasers described herein, to condenser lens 274. As shown in FIG. 19, the coupling lens group may include a number of refractive optical elements. Although one particular configuration of the coupling lens group is shown in FIG. 19, such a coupling lens group may have any suitable configuration, which may vary depending on, for example, the configuration of condenser lens 274. The coupling lens group may be used as a matching lens to focus the excitation light (e.g., IR light) through the condenser lens. Condenser lens 274 may be configured to focus the excitation light to a plasma as described herein (e.g., as described and shown in FIG. 18). In one embodiment, the focusing optics include at least one optical element configured to focus the excitation light to the plasma and configured to collect the light generated by the plasma. In one such embodiment, the at least one optical element includes a reflective optical element. FIG. 20 illustrates one embodiment of focusing optics that include such an optical element that may be used to couple excitation light (e.g., IR light) to a lamp. For example, as shown in FIG. 20, excitation light 276 is directed to cold mirror 278. Excitation light 276 may include any of the excitation light described herein that is generated by any of the lasers described herein (e.g., an IR laser). Cold mirror 278 may include a dichroic mirror or any other optical element that is configured to substantially transmit the excitation light (e.g., IR light) and to substantially reflect the light generated by the plasma (e.g., UV light). The excitation light may be distorted as it passes through the cold mirror (e.g., due to refraction of the excitation light by the cold mirror). In some embodiments, a lens group (not shown in FIG. 20) such as coupling lens group 270 shown in FIG. 19 or any other suitable lens or lenses may be positioned in the path of the excitation light before the excitation light passes through the cold mirror. The lens group may be included in the focusing optics to improve coupling of the excitation light to the cold mirror. The focusing optics include reflective optical element 280 that is configured to focus the excitation light to the plasma. The excitation light that passes through the cold mirror may be collected by reflective optical element 280, which may include any suitable reflective optical element (e.g., a spherical mirror, an elliptical mirror, or any other suitable reflective optical element) and may be further configured as described herein. LSP light source or lamp 282 is disposed in the reflective optical element. For example, LSP light source 282 may be disposed at one focal point of the reflective optical element such that the reflective optical element can focus the excitation light to the LSP light source. LSP light source 282 may be positioned at the focal point of the reflective optical element by mounting 284 that extends through aperture 286 in reflective optical element 280 and couples the LSP light source to another portion (not shown) of the system. Mounting 284 may include any suitable mounting known in the art. LSP light source 282 may be further configured as described herein. Reflective optical element 280 is also configured to collect the light generated by the plasma. Light (e.g., UV light and/or any other light described herein) generated by LSP light source 282 is collected by reflective optical element 280 and is directed to cold mirror 278. Cold mirror 278 is configured to direct the generated light collected by reflective optical element 280 to homogenizer 288 by reflecting the generated collected light in direction 290. Homogenizer 288 may include a light pipe or any other suitable homogenizer and may be further configured as described herein. The light exiting homogenizer 288 may be directed to one or more other optical components of the illumination subsystem (e.g., such as optical component 292, which may include an objective lens or any other suitable optical component) such that the light can be directed to a specimen thereby illuminating the specimen. The embodiment shown in FIG. 20 may be further configured as described herein and may be included in any of the systems described herein. Plot 294 shown in FIG. 20 is a power density simulation for the embodiment shown in FIG. 20. In particular, plot 294 illustrates power density as a function of position in the x direction for different values of z. The simulation was performed for an IR laser having a power of 750 W, a 50 μm beam diameter, and an NA of 0.2. As shown in plot 294, the maximum power density is achieved for a value of z=0.15. FIGS. 21-22 illustrate another embodiment of focusing optics that may be used to focus excitation light (e.g., IR light) to a lamp. FIG. 21 illustrates the excitation light beam path (e.g., the IR beam path), and FIG. 22 illustrates the generated light beam path (e.g., the UV beam path). This approach bypasses astigmatism from the cold mirror shown in FIG. 20. For example, as shown in FIG. 21, excitation light 296 (e.g., an IR beam) from a laser (not shown in FIGS. 21 and 22) is directed to reflective optical element 298, which may be a flat mirror or any other suitable reflective optical element. Reflective optical element 298 is configured to direct the excitation light to reflective optical element 300, which may also be a flat mirror or any other suitable reflective optical element. Reflective optical element 300 is configured to direct the excitation light to reflective optical element 302, which may include any suitable reflective optical element (e.g., a spherical mirror, an elliptical mirror, or any other suitable reflective optical element) and may be further configured as described herein. LSP light source or lamp 304 is disposed in reflective optical element 302. For example, LSP light source 304 may be disposed at one focal point of reflective optical element 302 such that the reflective optical element can focus the excitation light to a plasma (not shown in FIGS. 21 and 22) in the LSP light source. LSP light source 304 may be positioned at the focal point of reflective optical element 302 by mounting 306 that extends through aperture 308 in reflective optical element 302 and couples the LSP light source to another portion (not shown) of the system. Mounting 306 may include any suitable mounting known in the art. LSP light source 304 may be further configured as described herein. As shown in FIG. 22, light (e.g., UV light and/or any other light described herein) generated by LSP light source 304 is collected by reflective optical element 302 and is directed to reflective optical element 300. Reflective optical element 300 is configured to reflect the generated light collected by reflective optical element 302 to homogenizer 310. Reflective optical element 298 may preferably be positioned inside the obscuration of the NA caused by insertion of lamp 204 into reflective optical element 302. Therefore, reflective optical element 298 may not cause further obscuration of the NA. Homogenizer 310 may include a light pipe or any other suitable homogenizer and may be further configured as described herein. The light exiting homogenizer 310 may be directed to one or more other optical components of the illumination subsystem (e.g., such as optical component 312, which may include an objective lens or any other suitable optical component) such that the light can be directed to a specimen thereby illuminating the specimen. The embodiment shown in FIGS. 21 and 22 may be further configured as described herein and may be included in any of the systems described herein. Additional embodiments described herein generally relate to relatively efficient light collectors for illumination subsystems that use a combination of elliptical and spherical reflectors for optical inspection and/or any other processes described herein. The embodiments described further herein can be used with current illumination subsystems that utilize elliptical reflectors so that retrofit and upgrade of these illumination subsystems can be performed efficiently and cost effectively. In addition, the embodiments described further herein are configured to improve the light collection efficiency and the pupil-fill uniformity simultaneously. Furthermore, the embodiments described further herein can advantageously perform NA space folding which balances out the severe decrease of the high NA power due to shrinking plasma size, which is essential to improve the light collection efficiency. For example, the size of the plasmas described herein are much smaller than the size of currently used discharge arc lamps. The smaller size of the plasma causes much more non-uniformity in the pupil fill of illumination subsystems currently used with discharge arc lamps. In some embodiments, the system includes an illumination subsystem configured to illuminate the specimen during the process with the light generated by the plasma. In one such embodiment, the illumination subsystem is configured to collect the light generated by the plasma across a solid angle of about 4π. For example, the embodiments described herein can utilize the full 4π solid angle, which is the theoretical maximum. In one embodiment, the illumination subsystem includes a partial elliptical reflector and a half spherical reflector. For example, as shown in FIG. 23, the illumination subsystem may include partial elliptical reflector 314 and half spherical reflector 316. Therefore, the illumination subsystem utilizes a partial elliptical reflector in combination with a half spherical reflector for collection of the light generated by the plasma. In one such embodiment, the plasma is positioned at one focal point of the partial elliptical reflector, and the half spherical reflector is substantially centered to the plasma. For example, a plasma (not shown in FIG. 23) may be positioned at focal point 318 of the partial elliptical reflector, and half spherical reflector 316 may be substantially centered to the plasma positioned at focal point 318. In this manner, the half spherical reflector is centered to one of the foci of the partial elliptical reflector at which the plasma will be located. The partial elliptical reflector may be a partial elliptical reflector included in current illumination subsystems so that, as mentioned above, retrofit and upgrade of these illumination subsystems can be performed efficiently and cost effectively. As such, the partial elliptical reflector may or may not have the same configuration as currently used partial elliptical reflectors. For example, parameters of the partial elliptical reflector may or may not be: a=about 235,000 mm, where a=the long axis of the partial elliptical reflector; b=about 123,390 mm, where b=the short axis of the partial elliptical reflector; c=about 200,000 mm, where c = a 2 - b 2 ; e=about 0.851064, where e=eccentricity; F1=about 35 mm; F2=about 435 mm; EPD=about 195.02 mm, where EPD is the entrance pupil diameter or the diameter of the largest opening of the partial elliptical reflector; and central obscuration diameter=about 42 mm, where the central obscuration diameter is the smaller opening in the partial elliptical reflector that allows elements that mount the electrodeless lamp at the first focal point of the partial elliptical reflector to pass through the partial elliptical reflector to one or more other elements of the system. In addition, the collection angle of the partial elliptical reflector may be about 120 degrees (the collection angle for oversize collection or over-illumination), and the collection angle for an NA of about 0.9 at the specimen (e.g., wafer) may be about 111 degrees. The parameters (e.g., R (the radius of the half spherical reflector), EPD, central obscuration diameter, etc.) of the half spherical reflector may be determined using the following equations: sin φNA 0.9wafer=0.24 tan ⁢ ⁢ ϕ NA ⁢ ⁢ 0.9 ⁢ ⁢ wafer = a 2 - c 2 2 ⁢ ⁢ a ⁢ ⁢ c = 1 - e 2 2 ⁢ ⁢ e sin φNA0.12waferCMOobscuration=0.032 tan ⁢ ⁢ ϕ NA ⁢ ⁢ 0.12 ⁢ ⁢ waferCMO_obscuration = y x + c x 2 a 2 + y 2 b 2 = 1 tan ⁢ ⁢ θ ⁢ ⁢ min = y x - c x 2 a 2 + y 2 b 2 = 1 R=ra sin ⁢ ⁢ θ min = b 2 aR ⁡ [ 1 - R ⁢ ⁢ cos ⁢ ⁢ θ min 2 ⁢ ⁢ c ] r = ( 1 - e 2 ) ⁢ cos ⁢ ⁢ ϕ NA ⁢ ⁢ 0.9 ⁢ ⁢ wafer sin ⁢ ⁢ ( θ min + ϕ NA ⁢ ⁢ 0.9 ⁢ ⁢ wafer ) w=ra sin θmin θmax=180°−θmin L=2c−R In another embodiment, the partial elliptical reflector and the half spherical reflector are configured to collect the light generated by the plasma. The half spherical reflector is configured to direct the light collected by the half spherical reflector to the partial elliptical reflector. The partial elliptical reflector is configured to direct the light from the half spherical reflector and the light collected by the partial elliptical reflector to another optical element of the illumination subsystem. For example, as shown in FIG. 23, partial elliptical reflector 314 is configured to direct the light from half spherical reflector 316 and the light collected by the partial elliptical reflector to focal point 320 of the partial elliptical reflector at which another optical element of the illumination subsystem may be positioned or downstream of which another optical element of the illumination subsystem may be positioned. Therefore, the position of focal point 320 may define the location of intermediate image plane 322 of the illumination subsystem. The pupil plane (not shown) of the illumination subsystem shown in FIG. 23 may be downstream of the image plane shown in FIG. 23 and may vary depending on the configuration of other optical elements included in the illumination subsystem. In this manner, the light generated by the plasma in the solid angle from about 0 degrees to about 90 degrees will be collected by the partial elliptical reflector and focused to the second foci of the partial elliptical reflector. The light generated by the plasma in the solid angle from about 90 degrees up to about 180 degrees will be reflected by the half spherical mirror back through the first focal point of the partial elliptical reflector and will be recollected by the partial elliptical reflector, which is configured to focus the light reflected by the half spherical reflector to the second foci of the partial elliptical reflector. Therefore, using a half spherical reflector in combination with a partial elliptical reflector as described herein allows for collection of the light generated by the plasma across a much larger solid angle thereby increasing the collection efficiency of the illumination subsystem compared to illumination subsystems that include only the partial elliptical reflector. Increasing the collection efficiency of the illumination subsystem advantageously increases the brightness of the light generated by the plasma that can be used to illuminate the specimen. For example, the brightness of the light collected by an illumination subsystem including the partial elliptical reflector and half spherical reflector described herein may be about 1.3 times the brightness of the light collected by an illumination subsystem that includes only the partial elliptical reflector described herein. In addition, an optical element of the illumination subsystem such as a homogenizer, collection optics, or a condenser lens, all of which may be configured as described further herein, may be positioned at the second foci of the partial elliptical reflector or positioned in the path of the light focused to the second foci such that the optical element can collect the light focused to the second foci of the partial elliptical reflector. In this manner, the illumination subsystem may illuminate a specimen as described further herein with the light from the plasma focused to the second foci of the partial elliptical reflector. In some embodiments, the illumination subsystem described above is configured to direct the light to a pupil plane of the system such that the light has a substantially uniform intensity across the pupil plane. For example, the reflection from the half spherical reflector acts as a folding action in pupil space such that the final pupil fill includes the pupil fill due to the partial elliptical reflector, which decreases monotonically as NA increases, and the second pupil fill due to the combination of the half spherical reflector and the partial elliptical reflector, which increases monotonically. As a result, the final pupil fill is much more uniform than the pupil fill from the partial elliptical reflector alone. For example, the pupil intensity at 0.9 NA normalized to the peak pupil intensity may be about 10% when using the partial elliptical reflector without the half spherical reflector described herein. In other words, the intensity of the light at the edge of the pupil may only be about 10% of the peak intensity in the pupil. Such relatively large variation in the intensity of the light at the pupil plane is at least partially due to the fact that the magnification of the partial elliptical reflector varies across the partial elliptical reflector. Such variation in the magnification of the partial elliptical reflector causes rays that are reflected from different points on the partial elliptical reflector to have different intensities at the second focal point of the partial elliptical reflector and therefore at the pupil plane of the illumination subsystem. In particular, light rays reflected at relatively small angles from the partial elliptical reflector are relatively bright at the pupil plane while light rays reflected at relatively large angles from the partial elliptical reflector are relatively dim. As such, using the partial elliptical reflector without the half spherical reflector as described herein produces substantial non-uniformity in intensity across the pupil plane of the illumination subsystem. In contrast, the pupil intensity at 0.9 NA normalized to the peak pupil intensity may be greater than about 50% when using the partial elliptical reflector with the half spherical reflector as described herein. In other words, the intensity of the light at the edge of the pupil may be greater than about 50% of the peak intensity in the pupil. As such, using the partial elliptical reflector with the half spherical reflector as described herein results in much more uniformity in intensity across the pupil plane of the illumination subsystem compared to that achieved using only the partial elliptical reflector. Therefore, the embodiments described herein provide significant improvements in uniformity across the NA of the illumination subsystem and across apodization of the illumination subsystem. The embodiments described herein also have built-in flexibility to adjust the pupil fill profile for certain inspection applications. For example, one or more parameters of both the partial elliptical reflector and the half spherical reflector can be altered to achieve the desired pupil fill profile for different inspection applications. In this manner, the illumination subsystem configurations described herein advantageously provide more variable parameters that can be selected and/or adjusted based on the pupil fill profile than currently used illumination subsystems. The embodiment shown in FIG. 23 may be further configured as described herein. In addition, the embodiment shown in FIG. 23 may be included in any system embodiments described herein. Another embodiment relates to a method for providing illumination of a specimen for a process performed on the specimen. The method includes focusing excitation light from a laser to an electrodeless lamp to generate a plasma in the electrodeless lamp such that the plasma generates light. Focusing the excitation light to the electrodeless lamp may be performed as described herein (e.g., using any of the embodiments of the focusing optics described herein). The excitation light may include any of the excitation light described herein. The laser may include any of the lasers described herein. The electrodeless lamp and the plasma may be further configured as described herein. The light generated by the plasma may include any of the light described herein. The method also includes illuminating the specimen with the generated light during the process. Illuminating the specimen with the generated light may be performed as described further herein (e.g., using any of the embodiments of the illumination subsystems described herein). The specimen may include any of the specimens described herein. The process may include any of the processes described herein. Each of the steps of the method described above may be performed as described further herein. In addition, the method described above may be performed by any of the system embodiments described herein. Furthermore, the method described above may include any other step(s) of any other method(s) described herein. An additional embodiment relates to a method for determining one or more characteristics of a specimen. The method includes focusing excitation light from a laser to an electrodeless lamp to generate a plasma in the electrodeless lamp such that the plasma generates light. Focusing the excitation light from the laser to the electrodeless lamp may be performed according to any of the embodiments described herein (e.g., using any of the embodiments of the focusing optics described herein). The excitation light may include any of the excitation light described herein. The laser may include any of the lasers described herein. The electrodeless lamp and the plasma may be configured according to any of the embodiments described herein. The light generated by the plasma may include any of the light described herein. The method also includes illuminating the specimen with the generated light. Illuminating the specimen with the generated light may be performed as described further herein (e.g., using an illumination subsystem configured as described further herein). The specimen may include any of the specimens described herein. In addition, the method includes generating output responsive to light from the specimen resulting from the illuminating step. Generating the output responsive to the light from the specimen may be performed as described further herein (e.g., using a detection subsystem configured as described further herein). The light from the specimen may include any of the light described herein (e.g., light scattered from the specimen, light reflected by the specimen, light diffracted from the specimen, or some combination thereof). The method further includes determining the one or more characteristics of the specimen using the output. Determining the one or more characteristics may be performed as described further herein (e.g., using a processor as described further herein). The one or more characteristics may include any of the characteristics described herein. All of the methods described herein may include storing results of one or more steps of the method embodiments in a storage medium. The results may include any of the results described herein and may be stored in any manner known in the art. The storage medium may include any storage medium described herein or any other suitable storage medium known in the art. After the results have been stored, the results can be accessed in the storage medium and used by any of the method or system embodiments described herein, formatted for display to a user, used by another software module, method, or system, etc. For example, after the method determines the one or more characteristics of the specimen, the method may include storing the determined characteristic(s) in a storage medium. Furthermore, the results may be stored “permanently,” “semi-permanently,” temporarily, or for some period of time. For example, the storage medium may be random access memory (RAM), and the results may not necessarily persist indefinitely in the storage medium. In a similar manner, any of the embodiments of the systems described herein may be configured to store any of the results described herein in a storage medium as described above. Storing the results may be performed by any of the processors described herein. Each of the steps of the method described above may be performed as described further herein. In addition, the method described above may be performed by any of the system embodiments described herein. Furthermore, the method described above may include any other step(s) of any other method(s) described herein. Further modifications and alternative embodiments of various aspects of the invention may be apparent to those skilled in the art in view of this description. For example, methods and systems for providing illumination of a specimen for a process performed on the specimen are provided. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the general manner of carrying out the invention. It is to be understood that the forms of the invention shown and described herein are to be taken as the presently preferred embodiments. Elements and materials may be substituted for those illustrated and described herein, parts and processes may be reversed, and certain features of the invention may be utilized independently, all as would be apparent to one skilled in the art after having the benefit of this description of the invention. Changes may be made in the elements described herein without departing from the spirit and scope of the invention as described in the following claims.
	description	Modern radiation therapy techniques include the use of Intensity Modulated Radiotherapy (“IMRT”), typically by means of an external radiation treatment system, such as a linear accelerator, equipped with a multileaf collimator (“MLC”). Use of multileaf collimators in general, and an IMRT field in particular, allows the radiologist to treat a patient from a given direction of incidence to the target while varying the shape and dose of the radiation beam, thereby providing greatly enhanced ability to deliver radiation to a target within a treatment volume while avoiding excess irradiation of nearby healthy tissue. However, the greater freedom that IMRT and other complex radiotherapy techniques, such as volumetric modulated arc therapy (VMAT), where the system gantry moves while radiation is delivered, and three-dimensional conformal radiotherapy (“3D conformal” or “3DCRT”), afford to radiologists has made the task of developing treatment plans more difficult. As used herein, the term radiotherapy should be broadly construed and is intended to include various techniques used to irradiate a patient, including use of photons (such as high energy x-rays and gamma rays) and particles (such as electron and proton beams). While modern linear accelerators use MLCs, other methods of providing conformal radiation to a target volume are known and are within the scope of the present invention. Several techniques have been developed to create radiation treatment plans for IMRT or conformal radiation therapy. Generally, these techniques are directed to solving the “inverse” problem of determining the optimal combination of angles, radiation doses and MLC leaf movements to deliver the desired total radiation dose to the target, or possibly multiple targets, while minimizing irradiation of healthy tissue. This inverse problem is even more complex for developing arc therapy plans where the gantry is in motion while irradiating the target volume. Heretofore, radiation oncologists or other medical professionals, such as medical physicists and dosimetrists, have used algorithms to develop and optimize a radiation treatment plan. Optimization is often used in IMRT to achieve a radiation treatment plan that can fulfill a set of clinical goals in terms of a set of quality indexes. Quality indexes may include statistical quantities of a dose distribution produced by a radiation treatment plan. For example, quality indexes may include maximum dose Dmax for a planned target volume (PTV), minimum dose Dmin for the PTV, mean dose Dmean for an organ at risk (OAR), percentage of the PTV receiving 100% of the prescribed dose V100% (i.e., dose coverage), and the like. Clinical goals may be expressed in terms of a set of threshold values for the set of quality indexes. For example, clinical goals may include the maximum dose Dmax for the PTV should be less than or equal to 105% of the prescribed dose (i.e., Dmax_PTV≤105%), the minimum dose Dmin for the PTV should be greater than or equal to 95% of the prescribed dose (i.e., Dmin_PTV≥95%), the mean dose Dmean to the OAR should be less than 20 Gy (i.e., Dmean_OAR≤20 Gy), the percentage of the PTV receiving 100% of the prescribed dose V100% should be greater than 95% (i.e., V100%>95%), and the like. While a physician may be able to recognize a good treatment plan when such a plan has been obtained through optimization, it is difficult to specify a unique set of clinical goals prior to optimization. One possible approach is to use an initial set of clinical goals as a starting point to generate a reasonable candidate plan, and then interactively modify the dose distribution generated by the candidate plan to reach an optimal plan. One way of interactively modifying the plan is to directly make changes to the dose distributions, either in the three-dimensional fluence map or by modifying the dose volume histogram (DVH) curves, for various target structures and critical organs. In this approach, when a final optimal plan is reached, only the resultant dose distribution is recorded, which by itself may not clearly convey the physician's intent when she modified the dose distribution to reach the optimal plan. Therefore, it is desirable to have methods of interactively manipulating dose distribution in a treatment plan where the physician's intent may be preserved. According to some embodiments of the present invention, systems, methods, and apparatuses are provided for interactive manipulation of the dose distribution of a radiation treatment plan. For example, after an initial candidate treatment plan has been obtained, a set of clinical goals are transferred into a set of constraints. Each constraint may be expressed in terms of a threshold value for a respective quality index of the dose distribution. The threshold value may be referred to as a “constraint location” for the respective quality index. The dose distribution can then be modified interactively by modifying the constraint locations for the set of constraints. Re-optimization of the treatment plan may be performed based on the modified constraint locations. In this manner, the connection between a clinical goal and a constraint location is maintained. Thus, the physician's final intent is recorded as the changed constraint locations. In some embodiments, a user may assign relative priorities among the set of constraints. According to an embodiment, when a certain constraint is modified, a re-optimized treatment plan may not violate those constraints that have priorities that are higher than that of the modified constraint, but may violate those constraints that have priorities that are lower than that of the modified constraint. In another embodiment, the user may interactively change the relative priorities for one or more constraints. In a further embodiment, two or more constraints may share the same priority. In such cases, when a certain constraint is modified, a re-optimized treatment plan either can or cannot violate other constraints having the same priority. In other embodiments of the present invention, for cases where two or more clinical goals share the same priority or it is not clear which clinical goal is more important than the other, and the two or more clinical goals cannot be simultaneously met, an optimization algorithm may be designed to seek a solution that minimizes a “distance” to a region where all the clinical goals are met. In one embodiment, a user may specify a first set of threshold values for a set of quality indexes corresponding to the two or more clinical goals, as well as a second set of threshold values for the set of quality indexes. The constraint of the second set of threshold values may be easier to satisfy than the first set of threshold values. For example, the second set of threshold values may represent clinically acceptable threshold values, and the first set of threshold values may represent desired or preferred threshold values. A corresponding difference may be determined for each quality index from the first set of threshold values and the second set of threshold values. An optimal treatment plan may be obtained by optimizing a cost function that includes a plurality of terms (e.g., quadratic terms), where each term relates to a respective quality index, and the weight of each term relates to the difference for the respective quality index. In yet other embodiments of the present invention, a cost function can take into account both the quality indexes and their derivatives. The optimizer can also support clinical goals where the user has specified preferable trade-offs in advance. For example, the user can specify clinically insignificant changes as well as clinically significant changes for each quality index. In some implementations, the cost function can be generated and dynamically altered during optimization so that any solution achieving clinically significant improvement in one quality index while only deteriorating the other quality index by an insignificant amount may be accepted. In one embodiment, the optimizer may change the constraint location whenever the cost function gradient in a space spanned by the quality indexes has a much greater component with respect to one quality index compared to the other quality index. Other embodiments are directed to systems and computer readable media associated with methods described herein. A better understanding of the nature and advantages of embodiments of the present invention may be gained with reference to the following detailed description and the accompanying drawings. “Radiation” refers to any particles (e.g., photons, electrons, protons etc.) used to treat tissue, e.g., tumors. Examples of radiation include high energy x-rays, gamma rays, electron beams, and proton beams. The different particles can correspond to different types of radiation treatments. The “treatment volume” refers to the entire volume that will be subjected to radiation, and is sometimes referred to as the “irradiated volume.” The “target structure”, “target volume”, and “planning target volume” (“PTV”) refer to tissue intended to receive a therapeutic prescribed dose. A “radiation treatment plan” can include a dose distribution, machine parameters for achieving the dose distribution for a given patient, and information about the given patient. A dose distribution provides information about the variation in the radiation dose with spatial positions within a treatment area of the patient. A “dose distribution” can take many forms, e.g., a dose volume histogram (DVH) or a dose matrix. A DVH can summarize three-dimensional (3D) dose distributions in a graphical 2D format, e.g., where the horizontal axis is the dose (e.g., in units of grays—Gy) absorbed by the target structure (e.g., a tumor) and the vertical axis is the volume percentage. In a differential DVH, the height of a bar at a particular dose indicates the volume of the target structure receiving the particular dose. In a cumulative DVH, the height of a bar at a particular dose represents the volume of the structure receiving greater than or equal to that dose. The cumulative DVH is generally a curve (e.g., when small bin sizes are used), whereas the differential DVH is generally a disjoint bar graph. A drawback of a DVH is that it offers no spatial information; i.e., a DVH does not show where within a structure a dose is received. A dose matrix can provide the dose that each part of the body receives. The present disclosure relates generally to treatment planning for radiation therapy using external-beam radiation treatment systems, and is more particularly directed to interactive dose manipulation using prioritized constraints. For example, after an initial candidate treatment plan has been obtained, a set of clinical goals are transferred into a set of constraints. Each constraint may be expressed in terms of a threshold value for a respective quality index of the dose distribution. The dose distribution can then be modified interactively by modifying the threshold values for the set of constraints. Re-optimization may be performed based on the modified threshold values. Thus, the physician's final intent is recorded as the changed threshold values. In some embodiments, a user may assign relative priorities among the set of constraints. According to an embodiment, when a certain constraint is modified, a re-optimized treatment plan may not violate those constraints that have priorities that are higher than that of the modified constraint, but may violate those constraints that have priorities that are lower than that of the modified constraint. I. Treatment System In general, radiation therapy consists of the use of ionizing radiation to treat living tissue, usually tumors. There are many different types of ionizing radiation used in radiation therapy, including high energy x-rays, electron beams, and proton beams. The process of administering the radiation to a patient can be somewhat generalized regardless of the type of radiation used. External beam therapy (EBT), also called external radiation therapy, is a method for delivering a beam or several beams of high-energy x-rays to a patient's tumor. Beams are generated outside the patient (usually by a linear accelerator) and are targeted at the tumor site. FIGS. 1 and 2 depict a radiation treatment system of the type that may be used in connection with the present invention. Referring to FIG. 1, a perspective view of radiation treatment system (in this case a linear accelerator) is shown. Typically, such a system is capable of generating either an electron (particle) beam or an x-ray (photon) beam for use in the radiotherapy treatment of patients on a treatment couch 35. Other radiation treatment systems are capable of generating heavy ion particles such as protons. For purposes of the present discussion, only x-ray irradiation will be discussed. However, it will be appreciated by those skilled in the art that the same principles apply to other systems. Stand 10 supports a rotatable gantry 20 with a treatment head 30. Next to stand 10 there is arranged a control unit (not shown) that includes control circuitry for controlling the different modes of operation of the accelerator. A high voltage source is provided within the stand or in the gantry, to supply voltage to an electron gun (not shown) positioned on an accelerator guide located in the gantry 20. Electrons are emitted from the electron gun into the guide (not shown) where they are accelerated. A source supplies RF (microwave) power for the generation of an electric field within the waveguide. The electrons emitted from the electron gun are accelerated in the waveguide by the electric field, and exit the waveguide as a high energy electron beam, typically at megavoltage energies. The electron beam then strikes a suitable metal target, emitting high energy x-rays in the forward direction. Referring now to FIG. 2, a somewhat more detailed side view of a radiation treatment system of the type that may be used in connection with the present invention is shown. A patient P is shown lying on the treatment couch 35. X-rays formed as described above are emitted from the target in the treatment head 30 in a divergent beam 104. Typically, a patient plane 116, which is perpendicular to the page in FIG. 2, is positioned about one meter from the x-ray source or target, and the axis of the gantry 20 is located on the plane 116, such that the distance between the target and the isocenter 178 remains constant when the gantry 20 is rotated. The isocenter 178 is at the intersection between the patient plane 116 and the central axis of beam 122. A treatment volume to be irradiated is located about the isocenter 178. FIG. 3 shows schematically a photon collimation system 300 with upper jaws 310 (i.e., the Y1 and Y2 jaws; the Y1 jaw is omitted for clarity), lower jaws 320 (i.e., the X1 and X2 jaws), and a multileaf collimator (MLC) 330. The field dimensions in the plane 340 at the isocenter 178 are indicated. The upper jaws 310, the lower jaws 320, and the leaves 332 of the MLC 330 comprise an x-ray blocking material, and are positioned in the head 30 to define the width of the x-ray beam at the patient plane. Typically, the jaws 310 and 320 are moveable and, when fully open, define a maximum beam of about 40 cm×40 cm at the patient plane 116. The MLC 330 is positioned at the exit of the head 30, to further shape the x-ray beam. Since its introduction in 1990 the MLC has become a standard feature of most radiation treatment systems. Current MLCs sold by the assignee of the present invention use up to 120 individually controllable leaves, typically thin slices of tungsten, that can be moved into or out of the x-ray beam under the control of system software. FIG. 4 shows an exemplary MLC plane having a plurality of leaves 332, arranged in opposing pairs, and an aperture 415 created by selected leaf movements. Radiation passes through and is shaped by the aperture 415. Thus, the MLC can be used to collimate the x-rays to provide conformal treatment of tumors from various angles (“3D conformal”) as well as intensity modulated radiotherapy (“IMRT”), whereby different radiation doses are delivered to different portions of the treatment area. The treatment volume, i.e., the irradiated volume proximate to the isocenter 178 in the path of the x-ray beam, is defined by the jaws 310 and 320, the leaf sequence of the MLC 330, and the collimator angle, i.e., the angle at which the MLC 330 sits in the head 30. Some external radiation treatment systems may include multiple layers of MLCs. The multiple layers of MLCs may be positioned at different planes and at different collimator angles. FIG. 5 shows a block diagram of an external-beam radiation treatment system 500 of FIGS. 1 and 2. The radiation treatment system 500 includes a beam source 510, a beam aperture 520, a gantry 530, and a couch 540. The beam source 510 is configured to generate a beam of therapeutic radiation. This beam of radiation may include x-rays, particles, and the like. The beam aperture 520 includes an adjustable multi-leave collimator (MLC) 522 for spatially filtering the radiation beam. The couch 540 is configured to support and position a patient. The couch 540 may have six degrees of freedom, namely the translational offsets X, Y, and Z, and the rotation, pitch, and yaw. The gantry 530 that circles about the couch 540 houses the beam source 510 and the beam aperture 520. The beam source 510 is optionally configured to generate imaging radiation as well as therapeutic radiation. The radiation treatment system 500 may further include an image acquisition system 550 that comprises one or more imaging detectors mounted to the gantry 530. The radiation treatment system 500 further includes a control circuitry 560 for controlling the operation of the beam source 510, the beam aperture 520, the gantry 530, the couch 540, and the image acquisition system 550. The control circuitry 560 may include hardware, software, and memory for controlling the operation of these various components of the radiation treatment system 500. The control circuitry 560 can comprise a fixed-purpose hard-wired platform or can comprise a partially or wholly-programmable platform. The control circuitry 560 is configured to carry out one or more steps, actions, and other functions described herein. In some embodiments, the control circuitry 560 may include a memory for receiving and storing a radiation treatment plan that defines the control points of one or more treatment fields. The control circuitry 560 may then send control signals to the various components of the radiation treatment system 500, such as the beam source 510, the beam aperture 520, the gantry 530, and the couch 540, to execute the radiation treatment plan. In some embodiments, the control circuitry 560 may include an optimization engine 562 configured for determining a radiation treatment plan. In some other embodiments, the control circuitry 560 may not include an optimization engine. In those cases, a radiation treatment plan may be determined by an optimization engine in a separate computer system, and the radiation treatment plan is then transmitted to the control circuitry 560 of the radiation treatment system 500 for execution. II. Radiation Treatment Planning Radiation therapy is generally implemented in accordance with a radiation treatment plan that typically takes into account the desired dose of radiation that is prescribed to be delivered to the tumor, as well as the maximum dose of radiation that can be delivered to surrounding tissue. Various techniques for developing radiation treatment plans may be used. Preferably, the computer system used to develop the radiation treatment plan provides an output that can be used to control the radiation treatment system, including the control points and the MLC leaf movements. Typically, the desired dose prescribed in a radiation treatment plan is delivered over several sessions, called fractions. Several techniques have been developed to create radiation treatment plans for IMRT or conformal radiation therapy. Generally, these techniques are directed to solving the “inverse” problem of determining the optimal combination of angles, radiation doses and MLC leaf movements to deliver the desired total radiation dose to the target while minimizing irradiation of healthy tissue. This inverse problem is even more complex for developing arc therapy plans, such as volumetric modulated arc therapy (VMAT), where the one or more external treatment coordinates, such as the isocenter location, gantry angle, couch angles, and couch offsets, are in motion while irradiating the target volume. Heretofore, radiation oncologists or other medical professionals, such as medical physicists and dosimetrists, have used one of the available algorithms to develop and optimize a radiation treatment plan. Typically, such planning starts with volumetric information about the target tumor and about any nearby tissue structures. For example, such information may comprise a map of the planning target volume (“PTV”), such as a prostate tumor, which is prescribed by the physician to receive a certain therapeutic radiation dose with allowable tolerances. Volumetric information about nearby tissues may include for example, maps of the patient's bladder, spinal cord and rectum, each of which may be deemed an organ at risk (OAR) that can only receive a much lower, maximum prescribed amount of radiation without risk of damage. This volumetric information along with the prescribed dose limits and similar objectives set by the medical professionals are the basis for calculating an optimized dose distribution, also referred to as fluence map, which in turn is the basis for determining a radiation treatment plan. The volumetric information may, for example, be reduced to an objective function or a single figure of merit that accounts for the relative importance of various trade-offs inherent in a radiation treatment plan, along with constraints that must be met for the radiation treatment plan to be medically acceptable or physically possible. Treatment planning algorithms can account for the capabilities of the specific radiation treatment system they are used with, for example, the energy spectrum and intensity profile of the radiation beam, and the capabilities of the MLC. Generally speaking, treatment planning algorithms proceed by calculating the radiation dose received by each voxel in the treatment volume, adjusting one or more variable system parameters, such as the angle of irradiation or the positions of the MLC leaves, and then recalculating the dose received by each voxel. This process is ideally performed iteratively until an optimized plan is reached. However, the amount of time needed to perform the large number of calculations for each iteration places a practical limit on the number of iterations that can be performed. Accordingly, the algorithm is terminated after a predetermined amount of time, after a predetermined number of iterations, or after some other practical limit is reached. Generally speaking, there is a trade-off between the accuracy and speed of the different algorithms available for treatment planning. III. Interactive Dose Manipulation Using Prioritized Constraints Optimization is often used in IMRT to achieve a radiation treatment plan that can fulfill a set of clinical goals in terms of a set of quality indexes. While a physician may be able to recognize a good treatment plan when such a plan has been obtained through optimization, it might be difficult to specify a unique set of clinical goals prior to optimization. One possible approach may be to construct a cost function using an initial set of reference values for a set of quality indexes (the initial set of reference values are usually not the same as clinically acceptable threshold values but may be related to them), and perform optimization using the cost function to generate a reasonable candidate treatment plan. The candidate treatment plan produces an initial dose distribution. A user may then interactively modify the candidate plan by directly make changes to the initial dose distributions, either in the three-dimensional dose distribution or by modifying the dose volume histogram (DVH) curves, for various target structures and critical organs. In this approach, when a final optimal plan is reached, only the resultant dose distribution is recorded, which by itself may not clearly convey the physician's intent when she modified the dose distribution to reach the optimal plan. For example, it may not be clear whether the physician was trying to decrease the mean dose to an organ at risk (OAR), or to increase the percentage of the target volume (PTV) receiving 100% of the prescribed dose, when she modified the dose distribution. Thus, it may not be clear how the physician's intent could be transferred to a different field arrangement, a different fractionation scheme, or a modified patient anatomy. Another way of interactively modifying the plan may be to modify the initial set of clinical goals and then re-optimize the plan with the modified goals. This approach, however, may not allow direct study of trade-offs between different clinical goals. For example, a physician may wish to explore how much a quality index related to one clinical goal can be improved without deteriorating another quality index related to another clinical goal by more than a clinically significant amount. According to an embodiment of the present invention, in a method of interactive manipulation of the dose distribution of a radiation treatment plan, after an initial candidate treatment plan has been obtained, a set of clinical goals are transferred into a set of constraints. Each constraint may be expressed in terms of a threshold value for a respective quality index of the dose distribution. The threshold value may be referred to as a “constraint location” for the respective quality index. The dose distribution can then be modified interactively by modifying the constraint locations for the set of constraints. In this manner, the connection between a clinical goal and a constraint location is maintained. Thus, the physician's final intent is recorded as the changed constraint locations. In some embodiments, a user may assign relative priorities among the set of constraints. According to an embodiment, when a certain constraint is modified, in the re-optimization, any constraint having a priority that is higher than that of the modified constraint are forced to be met, while any constraint having a priority that is lower than that of the modified constraint is allowed be violated. In another embodiment, the user may interactively change the relative priorities for one or more constraints. In a further embodiment, two or more constraints may share the same priority. In such cases, when a certain constraint is modified, in the re-optimization, other constraints having the same priority are either forced to be met or are allowed to be violated. FIG. 6 illustrates an exemplary user interface that may allow a user to interactively manipulate the dose distribution of a radiation treatment plan according to an embodiment of the present invention. The section 620 in the middle of the user interface displays DVH curves for various optimization structures (e.g., the PTV, an OAR, and the like) that correspond to the initial dose distribution of the initial treatment plan that was determined using a set of initial set of reference values for a set of quality indexes. The section 630 on the right side of the user interface displays some two-dimensional slices of the three-dimensional dose distribution of the initial treatment plan. The section 610 on the left side of the user interface includes a plurality of fields 611-617. Each field corresponds to a clinical goal in terms of a respective quality index. For instance, in the example shown in FIG. 6, the first field 611 corresponds to the maximum dose Dmax for the planned target volume (PTV); the second field 612 corresponds to the minimum dose Dmin for the PTV; the third field 613 corresponds to the mean dose Dmean for an organ at risk (OAR) (e.g., the rectum); and the fields 614-617 correspond to various clinical goals relating to the dose to an OAR. Each field may include an initial threshold value for the corresponding treatment goal. For example, in the field 611, the initial threshold value for Dmax for the PTV is indicated as “Goal: Dmax≤107.00%.” The display area 618 in the section 610 allows the user to enter new threshold values (i.e., change the “constraint locations”) for the set of quality indexes. For example, in the field 612, the user may enter 95.85% as the new threshold value (i.e., the “desired” value) for Dmin to the PTV. The user can edit the number 619 in the display area 618. Alternatively, the user can make a change in the corresponding DVH graph in the middle section 620 of the user interface by dragging a handle 622 on the DVH graph to a desired location. For example, the user can drag the handle 622 of the DVH graph of an OAR to a lower dosage value. As the DVH graph is modified, the “desired” threshold value for the corresponding quality index may be updated accordingly in the display area 618. After the user has changed a threshold value for one of the clinical goals as discussed above, the system may re-optimize the treatment plan in order to meet the new threshold value for that clinical goal. Since the initial treatment plan is typically an optimized solution that is fully determined by multiple constraints, changing a single constraint may not result in a solution that can also meet all other constraints. In other words, a re-optimized treatment plan may have to violate one or more other constraints in order to meet the modified constraint. According to an embodiment of the present invention, the set of constraints are prioritized. For instance, in the example illustrated in FIG. 6, the constraint Dmax for the PTV is given the highest priority (i.e., having the priority of “1”); the constraint Dmin for the PTV is given the second highest priority (i.e., having the priority of “2”); the constraint Dmean for the OAR is given the third highest priority (i.e., having the priority of “3”); and the other constraints are given the shared fourth highest priority (i.e., having the priority of “4”). When a certain constraint is modified, a re-optimized treatment plan is not allowed to violate any constraint having a priority that is higher than that of the modified constraint, and is allowed to violate any constraint having a priority that is lower than that of the modified constraint. For instance, assume that a user changes the constraint location of Dmin for the PTV from 95.00% to 95.85%, as indicated by the circle 619 in the display area 618. Because the constraint regarding Dmax for the PTV has a priority (priority of “1”) that is higher than that of the constraint being modified (priority of “2”), a re-optimized treatment plan cannot violate the constraint regarding Dmax for the PTV (e.g., the value of Dmax for the PTV cannot be greater than 107.00%). On the other hand, because the constraint regarding Dmean for the OAR has a priority (priority of “3”) that is lower than that of the constraint being modified, the re-optimized treatment plan may violate the constraint regarding Dmean for the OAR (e.g., the value of Dmean for the OAR is allowed to go above 40.00 Gy). After re-optimization, the system may update the threshold values of lower priority constraints with achievable values. For instance, assuming that the lowest value achievable for Dmean for the OAR is 42.00 Gy after re-optimization, the system may update the threshold value of Dmean for the OAR to 42.00 Gy. In some embodiments, the user may choose to start with the constraint with the highest priority, and then proceed to the constraint with the next highest priority, and so on until all the constraints have been handled. In some embodiments, after handling a constraint with a lower priority, the user may wish to go back to a constraint with a higher priority. In this manner, the user can study the trade-offs among the various clinical goals until she finds an optimal achievable treatment plan. The method of interactive manipulation of the dose distribution according to embodiments of the present invention may afford several advantages as compared to conventional approaches. For example, in the manner described above, the connection between a clinical goal and a constraint location is maintained and the physician's intent is recorded as the changed threshold value for the constraint. In contrast, in an approach where changes are made directly to the dose distribution, only the resultant dose distribution is recorded, which may not clearly convey the physician's intent, and consequently it may not be clear how the physician's intent could be transferred to a different field arrangement, a different fractionation scheme, or a modified patient anatomy. In addition, in the manner described above, the physician can directly study the trade-offs among various clinical goals, which may not be as transparent in an approach where a modified set of clinical goals are used to re-optimize the treatment plan. In some cases, it may be difficult to determine the relative priorities among two or more clinical goals. Some embodiments can be generalized to cases where more than one clinical goal has the same priority. For example, when one constraint is modified, other constraints that have the same priority as that of the modified constraint, as well as those constraints with higher priorities, are forced to be met in the re-optimization; and only those constraints with lower priorities are allowed be violated. In another example, when one constraint is modified, other constraints that have the same priority as that of the modified constraint, as well as those constraints with lower priorities, are allowed to be violated in the re-optimization. In yet another example, a user may select whether or not other constraints having the same priority as that of the modified constraint are allowed to be violated in the re-optimization. Other user options and user actions may be possible. In one embodiment, the user may select that the constraint with the closest higher priority is also allowed to be violated in the re-optimization. In another embodiment, the user may be allowed to change the relative priorities of some of the clinical goals (e.g., as illustrated by the arrow 624 in FIG. 6). In yet another embodiment, instead of assigning priorities to the clinical goals, the user may select which constraints are allowed to be violated and which ones are forced to be met, so that she can study trade-offs among the various clinical goals. In a further embodiment, the user can create a new clinical goal as a new constraint, and the system may perform re-optimization including the newly added clinical goal. According to another embodiment, to allow a user to alter the three-dimensional dose distribution directly (so-called “painting dose”), the user can change the shape of an optimization structure, such as the contour of a PTV or an OAR. An interactive user action can be similar to using a brush tool in a painting application where the user is provided a “brush” with which she can change the shape of an optimization structure (thus this method may be referred to as “painting structure”). For example, if the user thinks that radiation dose should be delivered to a larger volume than the current volume of the PTV, the user can enlarge the contour of the PTV to enlarge its volume. The system may re-optimize the radiation treatment plan according to the enlarged PTV. FIG. 7 illustrates an exemplary user interface that can allow a user to interactively manipulate the dose distribution of a radiation treatment plan by changing the shape of an optimization structure, according to an embodiment of the present invention. The section 710 on the left side of the user interface includes a plurality of fields, each field corresponds to a clinical goal with respect to an optimization structure. For example, the field 712 corresponds to dose coverage of the PTV (i.e., percentage of the PTV receiving 100% of the prescribed dose). The section 730 on the right side of the user interface displays a two-dimensional slice of the three-dimensional dose distribution. If the user thinks that radiation dose should be delivered to a larger volume than the current volume of the PTV, she may select the field 712 in the section 710 that corresponds to dose coverage to the PTV. In response to the selection of field 712, the contour 736 of the PTV would become active in the dose distribution image in the section 730 of the user interface. For example, the contour 736 of the PTV may be depicted in red color, as illustrated in FIG. 7. The user may then select the brush tool icon 732 on the top of the section 730. The cursor would then be changed into a “brush” 734. The user can use the brush to make contour 736 of the PTV larger by painting it larger. In one embodiment, the system may re-optimize the radiation treatment plan according to the enlarged PTV. According to another embodiment, a method of interactive manipulation of the dose distribution of a radiation treatment plan may be described as follows. First, an initial set of candidate treatment plans are generated by selecting all treatment plans that can be realized with the selected patient geometry and field geometry restrictions. Next, a set of clinical goals are converted into a set of constraints. The set of constraints are ranked with relative priorities in an order of importance. According to an embodiment, a physician may start with modifying the constraint having the highest priority, and check if there exists a subset of the candidate treatment plans satisfying the modified constraint that is non-empty. If the subset is non-empty, that clinical goal is marked as met and the initial set of candidate treatment plans is replaced by the subset. If the subset is empty (i.e., none of the treatment plans in the initial set can meet the modified constraint), that clinical goal is marked as not met. In one embodiment, the initial set of candidate treatment plans is kept unchanged. In another embodiment, the initial set of candidate treatment plans is replaced with a subset where the quality index value associated to that clinical goal reaches a value that is as close to clinically acceptable value as possible. In one embodiment, the constraint location for that clinical goal may be updated to the location that is achievable. The physician may then proceed to handle the constraint of the next highest priority. This process may be repeated until all constraints have been handled. According to an embodiment, once all clinical goals have been handled, a final optimal treatment plan may be selected from the final subset of treatment plans. In some embodiments, the final optimal treatment plan may be obtained by optimizing an appropriate cost function. For example, the cost function may be designed to minimize the amount of violation of the most important un-met constraint. Alternatively, the cost function may be designed to leave as much margin as possible for the most important fulfilled constraint. Other criteria may also be used in the construction of the cost function. The optimized treatment plan may be considered as optimally fulfilling the set of clinical goals. FIG. 13 shows a simplified flowchart illustrating a method 1300 of determining an optimal radiation treatment plan using an external-beam radiation treatment system according to an embodiment of the present invention. At 1302, a first clinical goal and a second clinical goal are received via a user interface of a computer system. The first clinical goal includes a first acceptable threshold value and a first desired threshold value for a first quality index. The second clinical goal includes a second acceptable threshold value and a second desired threshold value for a second quality index. In some embodiments, the difference between the first acceptable threshold value and the first desired threshold value may correspond to a clinically insignificant change for the first quality index, and the difference between the second acceptable threshold value and the second desired threshold value may correspond to a clinically insignificant change for the second quality index. At 1304, a cost function is obtained. The cost function includes a first term with a first weight and a second term with a second weight. The first term is proportional to a value of the first quality index in excess of the first acceptable threshold value, and the second term is proportional to a value of the second quality index in excess of the second acceptable threshold value. The first weight is inversely proportional to a difference between the first desired threshold value and the first acceptable threshold value, and the second weight is inversely proportional to a difference between the second desired threshold value and the second acceptable threshold value. At 1306, optimization is performed using the cost function to obtain an optimal radiation treatment plan that has an optimal value for the cost function. In some embodiments, the first term of the cost function is proportional to square of the value of the first quality index in excess of the first acceptable threshold value, and the second term is proportional to square of the value of the second quality index in excess of the second acceptable threshold value. The first weight is inversely proportional to square of the difference between the first desired threshold value and the first acceptable threshold value, and the second weight is inversely proportional to square of the difference between the second desired threshold value and the second acceptable threshold value. For example, the cost function may have the form expressed in Equation (1). V. Generating a Radiation Treatment Plan Based on Clinical Goals and Trade-Offs Among the Clinical Goals In optimizing a radiation treatment plan, it is often necessary to interpret a set of user defined clinical goals in terms of a cost function. The cost function assigns a single scalar value for each plan as a function of all the “microscopic” degrees of freedom (MDF) in the treatment plan. The MDF can be the set of all fluence pixels in all fields or the set of all free machine parameters needed to deliver the treatment plan. The optimization problem may be then reduced to finding a plan that has the minimum cost function value. In some cases where more than one clinical goals are provided, it may not be guaranteed that all clinical goals can be fulfilled simultaneously, as described in the previous section in relation to FIG. 9. One approach may be to also specify the relative priorities of the different clinical goals, so as to instruct the optimizer which goal should be fulfilled first. On the other hand, in some cases there may be more than one treatment plans that can satisfy all clinical goals. For instance, in the example illustrated in FIG. 11, any point in the portion of region 1140 below the horizontal straight line 1120 and to the left of the vertical straight line 1110 may represent a solution that satisfies both clinical goals (x0, y0) simultaneously. In such cases, the set of clinical goals (x0, y0) may not uniquely determine an optimal plan, but only reduces the set of achievable plans. In some cases, however, it may be difficult to assign a unique priority to each of the clinical goals, or there may be two or more clinical goals that are considered as equally important and yet cannot both be fulfilled at the same time. For instance, consider the example illustrated in FIG. 9. The horizontal axis and the vertical axis are the values of a first quality index Q1 and a second quality index Q2, respectively. For example, the first quality index Q1 may relate to the mean dose Dmean to an OAR (e.g., the spine), and the second quality index Q2 may relate to the maximum dose Dmax to a PTV. A first clinical goal may be expressed in terms of the first quality index Q1 as Q1≤x0, represented by the vertical straight line 910; and a second clinical goal may be expressed in terms of the second quality index Q2 as Q2≤y0, represented by the horizontal straight line 920. The shaded area 930 in the lower left quadrant may represent a region where both the first clinical goal and the second clinical goal are simultaneously satisfied. In some cases, however, for a particular set of patient geometry and field geometries, an achievable solution may not be found where both the first clinical goal and the second clinical goal can be fulfilled at the same time. For instance, the shaded region 940 represents the region where achievable solutions can be found for a set of given patient geometry and field geometries. In this example, there is no overlap between the shaded region 940 and the shaded region 930, which means that there is no achievable solution that can fulfill both the first clinical goal and the second clinical goal simultaneously. In such a case, the point 960, where the vertical line 910 and the border line 950 of the region 940 intersects, may represent an achievable solution that fulfills the first clinical goal with a minimum amount of violation of the second clinical goal. Similarly, the point 970, where the horizontal line 920 and the border line 950 of the region 940 intersects, may represent an achievable solution that fulfills the second clinical goal with a minimum amount of violation of the first clinical goal. Thus, if the first clinical goal is considered to be more important than the second clinical goal, then the point 960 may represent an optimal treatment plan. On the other hand, if the second clinical goal is considered to be more important than the first clinical goal, the point 970 may represent an optimal treatment plan. However, in cases where it is not clear whether the first clinical goal is more important than the second clinical goal or vice versa, or the first clinical goal and the second clinical goal are equally important, perhaps neither the point 960 nor the point 970 represents an optimal solution. For cases where two or more clinical goals share the same priority or it is not clear which clinical goal is more important than the other, embodiments may be designed to seek a solution that minimizes the “distance” to the region where all the clinical goals are met. For instance, in the example illustrated in FIG. 9, a solution represented by the point 980, which is located somewhere between the point 960 and the point 970 along the border line 950 of the region 940. At the point 980, although neither the first clinical goal nor the second clinical goal is met, it may have the closest “distance” to the region 930 where both the first clinical goal and the second clinical goal are met. Referring to FIG. 10, consider two quality indexes Q1 and Q2, represented by the horizontal axis and the vertical axis, respectively. According to an embodiment of the present invention, a user may specify a first set of threshold values for Q1 and Q2 as follows:Q1≤x0, and Q2≤y0.The first set of threshold values (x0, y0) may be represented by the point 1032 in FIG. 10. In addition, the user may specify a second set of threshold values for Q1 and Q2 as follows:Q1≤x1, and Q2≤y1,where x1>x0, and y1>y0. The second set of threshold values (x1, y1) may be represented by the point 1042 in FIG. 10. Thus, it may be easier to fulfill to the second set of threshold values (x1, y1) than the first set of threshold values (x0, y0), as the second set of threshold values are higher. The user may assign a higher priority for meeting the second set of threshold values, and a lower priority for meeting the first set of threshold values. For example, the second set of threshold values (x1, y1) may represent clinically acceptable threshold values for the quality indexes Q1 and Q2 and thus has to be met, whereas the first set of threshold values (x0, y0) may represent desired or preferred threshold values for the quality indexes Q1 and Q2 and can be violated. In one embodiment, the point 1032 resides outside the region 1040 where achievable solutions can be found; and the point 1042 resides inside the region 1040. In other words, the first set of clinical goals (x0, y0) cannot be simultaneously fulfilled, while the second set of clinical goals (x1, y1) can be simultaneously fulfilled. An optimizer may construct a cost function designed to reach a solution represented by the point 1080, where the straight line connecting the point 1032 and the point 1042 intersects with the border line 1050 of the region 1040 where solution can be found. The point 1080 may represent an achievable solution that has the minimum “distance” to the region where the first set of threshold values are simultaneously met. As can be seen in FIG. 10, the location of the point 1080 may depend on the values of δx and δy, where δx=x1-x0, and δy=y1-y0. In a case where δx=0 and δy is finite, the optimal solution may be represented by the point 1060 where the clinical goal of x0 for Q1 is met. This may be the case where the threshold value x0 for Q1 is so critical such that it has to be met. Conversely, in a case where δy=0 and δx is finite, the optimal solution may be represented by the point 1050 where the threshold value of y0 for Q2 is met. This may be the case where the threshold value y0 for Q2 is so critical such that it has to be met. For cases where both δx and δy are non-zero, a cost function may be constructed to include a weighted sum of two quadratic terms as:z=w1{max[0,(Q1−x0)]}2+w2{max[0,(Q2−y0)]}2, (1)where w 1 = 1 ( δ ⁢ ⁢ x ) 2 , and ⁢ ⁢ w 2 = 1 ( δ ⁢ ⁢ y ) 2 . Thus, an increase in Q1 in excess of x0, as well as an increase in Q2 in excess of y0, will incur increasing cost, and the relative weights of the first term and the second term are inversely proportional to square of δx and δy, respectively. Therefore, if δx>δy, the second term would have a greater weight than the first term; conversely, if δy>δx, the first term would have a greater weight than the first term. The cost function as expressed in Equation (1) may guide the optimizer toward a solution represented by the point 1080 in FIG. 10, which may be considered as the optimal solution having a minimum weighted “distance” to the region where the desired threshold values of (x0, y0) are simultaneously fulfilled. In other embodiments, the terms of the cost function may have forms other than quadratic functions. For example, they may be polynomial functions of an order higher than two, or they may be exponential functions. In some embodiments, the weights w1 and w2 may have forms other than quadratic functions as well. For example, they may be polynomial functions of an order higher than two, or they may be exponential functions. It should be understood that, although the above discussion refers to only two clinical goals expressed in terms of two quality indexes, embodiments can be extended to cases where more than two clinical goals expressed in terms of more than two quality indexes are considered. In an alternative embodiment, instead of defining a first set of threshold values (x0, y0) and a second set of threshold values (x1, y1), the user may define a set of desired threshold values (x0, y0), and a set of clinically insignificant changes for Q1 and Q2 as (δx, δy). A cost function similar to the cost function expressed in Equation (1) may be used to find an optimal solution. The optimization method described above can also be applied to cases where the desired threshold values (x0, y0) can be simultaneously fulfilled. For instance, consider the example illustrated in FIG. 11. Here, the point 1132 corresponding to (x0, y0) is located within the region 1140 where solutions can be found. As such, all solutions located within the portion of the region 1140 that is below the horizontal line 1120 and to the left of the vertical line 1110 may satisfy both of the desired threshold values x0 and y0. Therefore, an optimal treatment plan may not be uniquely defined. The solution corresponding to the point 1160 may provide the largest margin to the desired threshold value x0 for the quality index Q1 (i.e., the largest amount by which the actual value of the quality index Q1 falls below the desired threshold value x0), whereas the solution corresponding to the point 1170 may provide the largest margin to the desired threshold value y0 for the quality index Q2. Instead of seeking a solution that provides the largest margin to the desired threshold value for either of the quality indexes Q1 and Q2, the optimizer may seek a solution that maximizes the margin in terms of the “distance” to the point 1132 having the desired threshold values (x0, y0). Assume that the point 1142 corresponds to the acceptable threshold values (x1, y1). In one embodiment, the optimizer may seek to find a solution represented by the point 1180, where the extension of the straight line connecting the point 1132 and the point 1142 intersects with the border line 1150 of the region 1140, as point 1180 may provide the largest margin in terms of the weighted “distance” to the point 1132. FIG. 12 illustrates an exemplary user interface that may be used in the optimization process according to an embodiment of the present invention. The section 1210 on the left side of the user interface includes a plurality of fields 1211-1217. Each field corresponds to a clinical goal with regard to a respective quality index. For each clinical goal, a user may specify a first threshold value and a second threshold value for the respective quality index. In some embodiments, the first threshold value may be a preferred value, and the second threshold value may be an acceptable value. For instance, in the example illustrated in FIG. 12, the first threshold value is shown as the “GOAL,” and the second threshold value is shown as the “Var.” For example, in the first field 1211, the first threshold value for Dmax to the PTV is specified to be 105%, and the second threshold value for Dmax to the PTV is specified to be 107%. In some embodiments, the user may interactively change the first threshold value and/or the second threshold value for each clinical goal during the optimization process. The optimizer may perform optimization of a treatment plan based on the specified threshold values for the clinical goals using the method described above. Consider a case where two clinical goals are presented in terms of threshold values for two quality indexes Q1 and Q2 as Q1≤x0 and Q2≤y0. One way of constructing a cost function is to include a weighted sum of two quadratic terms as,z=wj{max[0,(Q1−x0)]}2+w2{max[0,(Q2−y0)]}2, (2)where w1 and w2 are the weights for the two quadratic terms. Referring to FIG. 14, the point 1410 correspond to the threshold values (x0, y0) and may be referred to as the “objective location.” The contour lines 1420a-1420e represent a set of iso-curves of the cost function z. The objective of an optimization may be to minimize the value of the cost function z for a set of patient geometry and field geometries. For instance, in the example illustrated in FIG. 14, the shaded region 1440 represents the region where achievable solutions can be found for a given patient geometry. The point 1442 where the iso-curve 1420e just touches the border line 1450 of the region 1440 may represent an optimal achievable solution that has the lowest possible cost function value. The constraint location 1410 is usually chosen such that the reference values (x0, y0) are related to but not the same as clinically acceptable threshold values for Q1 and Q2. In other words, the objective location 1410 is usually selected to be outside the region 1440, so that the cost function has a finite gradient and thus can be minimized. Choosing the objective location 1410 usually requires some experience. According to some embodiments, users may set the objective location manually. In some cases, however, it may be problematic to use a static cost function that only depends on the threshold values for the clinical goals. In some cases, a physician may not consider a treatment plan that satisfies a set of clinical goals as the best possible plan. For instance, consider the examples illustrated in FIG. 15. The point 1510 is the objective location. Contour lines 1520a-1520g are the iso-curves of a cost function as expressed in Equation (2). Consider a first case where a first feasible solution space for a first patient geometry is defined by the first border curve 1550. In this case, the point 1552, where the iso-curve 1520g of the cost function just touches the first border curve 1550, may represent a potential optimal solution. Now consider a second case where a second feasible solution space for a second patient geometry is defined by the second border curve 1560. Here, the point 1562, where the iso-curve 1520g of the cost function just touches the second border curve 1560, may represent a potential optimal solution. Thus, although the solution corresponding to the point 1552 and the solution corresponding to the point 1562 lie on the same iso-curve and hence have the same cost function value, the two solutions are obviously very different. This illustrates that the same form of cost function may lead to very different solutions depending on the shape of the solution space. In some cases, a physician may prefer to consider trade-offs between two quality indexes where much can be gained in one quality index without reducing significantly the other. For instance, in the first example illustrated in FIG. 15, the point 1552 lies on a section of the first border curve 1550 where it is substantially horizontal. This means that another solution in the vicinity of the point 1552 along the border curve 1550 may only incur a small change in the value of Q2 but can have a large reduction in the value of Q1. For example, consider the alternative solution represented by the point 1554. Its value of Q2 is only slightly increased from the value of Q2 at the point 1552, yet its value of Q1 is significantly reduced from the value of Q1 at the point 1552. Thus, a physician may prefer the alternative solution represented by the point 1554 over the solution represented by the point 1552, as long as the increase in the value of Q2 is within the clinically insignificant change of Q2. Similarly, in the second example illustrated in FIG. 15, the point 1562 lies on a section of the second border curve 1560 where it is substantially vertical. This means that another solution in the vicinity of the point 1562 along the border curve 1560 may only incur a small change in the value of Q1 but can have a large reduction in the value of Q2. For example, consider the alternative solution represented by the point 1564. Its value of Q1 is only slightly increased from the value of Q1 at the point 1562, yet its value of Q2 is significantly reduced from the value of Q2 at the point 1562. Thus, a physician may prefer the alternative solution represented by the point 1564 over the solution represented by the point 1562, as long as the increase in the value of Q1 is within the clinically insignificant change of Q1. In cases where the objective location is far inside the region where the solution can be found, consideration of trade-offs may be even more important, as optimization may be driven by some secondary terms, such as fluence smoothing and monitor unit (MU) count objectives. As discussed above with relation to FIG. 15, it may be desirable to construct a cost function that not only takes into account a set of clinical goals, but also possible trade-offs among the set of clinical goals. According to embodiments of the present invention, an optimizer can support clinical goals where the user has specified preferable trade-offs in advance. For example, the user can specify clinically insignificant changes as well as clinically significant changes for each quality indexes. In some embodiments, the cost function can be generated and dynamically altered during optimization so that any solution achieving clinically significant improvement in one quality index while only deteriorating the other quality index by an insignificant amount may be accepted. In one embodiment, the optimizer may change the objective location whenever the cost function gradient in a space spanned by the quality indexes has a much greater component with respect to one quality index compared to the other quality index. According to an embodiment of the present invention, a cost function may include a term relating to threshold values for the quality indexes, as well as terms relating to user-specified clinically insignificant and clinically significant changes for the quality indexes. For example, consider two clinical goals involving a first quality index Q1 and a second quality index Q2. The optimizer may construct a cost function z that may include the following three terms, w 1 2 ⁢ { max ⁡ [ 0 , ( Q 1 - x 0 ) ] } 2 + w 2 2 ⁢ { max ⁡ [ 0 , ( Q 2 - y 0 ) ] } 2 } , ( 3 ) w 1 ⁢ δ ⁢ ⁢ x L · Q 1 + w 2 ⁢ δ ⁢ ⁢ y H · Q 2 + ax , ( 4 ) w 1 ⁢ δ ⁢ ⁢ x H · Q 1 + w 2 ⁢ δ ⁢ ⁢ y L · Q 2 + bx , ( 5 ) where each term presents the cost function in a different region of the (Q1, Q2) plane. The values of x0 and y0 define a constraint location; δxL and ∂yL are the user-specified clinically insignificant changes in Q1 and Q2, respectively; δxH and δyH are the user-specified clinically significant changes in Q1 and Q2, respectively; w1 and w2 are relative weights. The region borders and the parameters a and b are selected so that the cost function contours are continuous and smooth. Normally δcH>δxL, and dyH>δyL. For example, assume that Q1 corresponds to the maximum dose Dmax to an OAR. A user may specify that the clinically insignificant change for Q1 δxL is 0.5 Gy, and the clinically significant change for Q1 δxH is 5 Gy. In some embodiments, the second term expressed in Equation (4) and the third term expressed in Equation (5) may guide the optimization toward a solution that keeps the quality index gradients within the bounds of δxL and δuL, and δxH and dyH. For example, referring to FIG. 15, in the case where the border line for the region where the solution can be found is defined by the curve 1550, the new cost function may be designed to have its iso-curves shaped such that it may lead to the solution located at point 1554 instead of 1552, so as to take advantage of the beneficial trade-offs. On the other hand, in the case where the border line for the region where the solution can be found is defined by the curve 1560, the new cost function may be designed to have its iso-curves shaped such that it will lead to the solution located at point 1564 instead of 1562, so as to take advantage of the beneficial trade-offs. It should be understood that, although the above discussion refers to only two quality indexes, the method can be extended to cases where more than two quality indexes are considered. In some embodiments, instead of specifying clinically significant changes and clinically insignificant changes for the quality indexes, the user may specify desired threshold values as well as acceptable threshold values for the quality indexes. For example, the user may specify the desired threshold values for Q1 and Q2 as x0 and y0, respectively, and specify the acceptable threshold values for Q1 and Q2 as x1 and y1, respectively, where x1>x0 and y1>y0. The desired threshold values x0 and y0 would be the primary driver for the optimization, and the acceptable threshold values x1 and y1 are used to constrain the optimizer's search for user preferred trade-offs. In another embodiment, the optimizer may construct a cost function z that includes the following two terms,w1{max[0,(Q1−x0)]}2+w2{max[0,(Q2−y0)]}2, (6)w12 max{0,(Q1−x0)} max{0,(Q2−y0)}, (7)where the weights w1, w2, and w12 are selected such that certain quality index gradients are preferred. The cross term expressed in Equation (7) may guide the optimizer toward an optimal solution that takes advantages of any beneficial trade-offs. According to an embodiment of the present invention, the optimizer may change the objective location whenever the cost function gradient in a space spanned by the quality indexes has a much greater component with respect to one quality index compared to the other quality index. For instance, in the example illustrated in FIG. 15, consider the solution corresponding to the point 1552. Since this point is almost directly above the constraint location 1510, the cost function value at this point has a much greater contribution from the term w2 {max [0, (Q2−y0)]}2 than from the term w1{max [0, (Q1−x0)]}2. This means that the solution 1552 is located at a position where the gradient of the quality index Q1 is very high, i.e., a small reduction in the value of Q2 can cause large increase in the value of Q1. In one embodiment, upon recognizing such a situation, the optimizer may move the objective location 1510 toward the left, i.e., reducing the value of x0, so that the cost function value may have a greater contribution from the term w1{max [0, (Q1−x0)]}2. In some embodiments of the present invention, trade-off information may be deduced from knowledge models. For example, potentially beneficial trade-offs may be deduced automatically from a selected set of existing treatment plans using machine learning algorithms, such as those similar to some current DVH estimation algorithms. In some other embodiments, similar approaches can be used to restrict the solution space in multi-criteria-optimization (MCO), where the cost function is a vector valued function. The optimization approaches described above may afford several advantages. For example, in cases where a set of clinical goals does not uniquely determine an optimal plan but only reduces the set of achievable plans, or in cases where not all clinical goals can be satisfied, taking into account information about the acceptable or preferred trade-offs in the optimization can guide the optimizer to the optimal treatment plan. FIG. 16 illustrates an exemplary user interface that may be used in the optimization process according to an embodiment of the present invention. The section 1610 on the left side of the user interface includes a plurality of fields 1611-1617. Each field corresponds to a clinical goal with regard to a respective quality index. In some embodiments, for each clinical goal, a user may specify a desired threshold value (i.e., the “GOAL”), as well as a clinically “significant change” and a clinically “insignificant change,” for the respective quality index. For example, in the first field 1611, the desired threshold value for Dmax to the PTV is specified to be 105%, the clinically significant change is specified to be 1%, and the clinically insignificant change is specified to be 0.1%. The system may optimize a treatment plan based on the user-specified threshold values, as well as clinically significant changes and clinically insignificant changes. In some embodiments, the user may interactively change the desired threshold values, as well as the clinically significant changes and the clinically insignificant changes during the optimization process. FIG. 17 shows a simplified flowchart illustrating a method 1700 of determining an optimal radiation treatment plan using an external-beam radiation treatment system according to an embodiment of the present invention. At 1702, a first clinical goal and a second clinical goal is received via a user interface of a computer system. The first clinical goal includes a first threshold value for a first quality index relating to a first statistical quantity of a dose distribution. the second clinical goal includes a second threshold value for a second quality index relating to a second statistical quantity of the dose distribution. At 1704, a first clinically significant change and a first clinically insignificant change for the first quality index are received. Also, a second clinically significant change and a second clinically insignificant change for the second quality index are received. At 1706, a cost function is obtained. The cost function includes a first term, a second term, and a third term. The first term is proportional to a value of the first quality index in excess of the first threshold value and proportional to a value of the second quality index in excess of the second threshold value. The second term relates to the first clinically insignificant change for the first quality index and to the second clinically significant change for the second quality index. The third term relates to the first clinically significant change for the first quality index and to the second clinically insignificant change for the second quality index. In one embodiment, the first term of the cost function may have the form expressed in Equation (3). At 1708, optimization is performed using the cost function to obtain an optimal radiation treatment plan that has an optimal value for the cost function. In some embodiments, the second term of the cost function is proportional to a product of the first clinically insignificant change and the value of the first quality index, and proportional to a product of the second clinically significant change and the value of the second quality index. For example, the second term may have the form expresses in Equation (4). The third term of the cost function is proportional to a product of the first clinically significant change and the value of the first quality index, and proportional to a product of the second clinically insignificant change and the value of the second quality index. For example, the third term may have the form expressed in Equation (5). VI. Computer System Any of the computer systems mentioned herein may utilize any suitable number of subsystems. Examples of such subsystems are shown in FIG. 18 in computer system 1800. In some embodiments, a computer system includes a single computer apparatus, where the subsystems can be the components of the computer apparatus. In other embodiments, a computer system can include multiple computer apparatuses, each being a subsystem, with internal components. The subsystems shown in FIG. 18 are interconnected via a system bus 1875. Additional subsystems such as a printer 1874, keyboard 1878, storage device(s) 1879, monitor 1876, which is coupled to display adapter 1882, and others are shown. Peripherals and input/output (I/O) devices, which couple to I/O controller 1871, can be connected to the computer system by any number of means known in the art, such as serial port 1877. For example, serial port 1877 or external interface 1881 (e.g. Ethernet, Wi-Fi, etc.) can be used to connect computer system 1800 to a wide area network such as the Internet, a mouse input device, or a scanner. The interconnection via system bus 1875 allows the central processor 1873 to communicate with each subsystem and to control the execution of instructions from system memory 1872 or the storage device(s) 1879 (e.g., a fixed disk, such as a hard drive or optical disk), as well as the exchange of information between subsystems. The system memory 1872 and/or the storage device(s) 1879 may embody a computer readable medium. Any of the data mentioned herein can be output from one component to another component and can be output to the user. A computer system can include a plurality of the same components or subsystems, e.g., connected together by external interface 1881 or by an internal interface. In some embodiments, computer systems, subsystem, or apparatuses can communicate over a network. In such instances, one computer can be considered a client and another computer a server, where each can be part of a same computer system. A client and a server can each include multiple systems, subsystems, or components. It should be understood that any of the embodiments of the present invention can be implemented in the form of control logic using hardware (e.g. an application specific integrated circuit or field programmable gate array) and/or using computer software with a generally programmable processor in a modular or integrated manner. As used herein, a processor includes a multi-core processor on a same integrated chip, or multiple processing units on a single circuit board or networked. Based on the disclosure and teachings provided herein, a person of ordinary skill in the art will know and appreciate other ways and/or methods to implement embodiments of the present invention using hardware and a combination of hardware and software. Any of the software components or functions described in this application may be implemented as software code to be executed by a processor using any suitable computer language such as, for example, Java, C++ or Perl using, for example, conventional or object-oriented techniques. The software code may be stored as a series of instructions or commands on a computer readable medium for storage and/or transmission, suitable media include random access memory (RAM), a read only memory (ROM), a magnetic medium such as a hard-drive or a floppy disk, or an optical medium such as a compact disk (CD) or DVD (digital versatile disk), flash memory, and the like. The computer readable medium may be any combination of such storage or transmission devices. Such programs may also be encoded and transmitted using carrier signals adapted for transmission via wired, optical, and/or wireless networks conforming to a variety of protocols, including the Internet. As such, a computer readable medium according to an embodiment of the present invention may be created using a data signal encoded with such programs. Computer readable media encoded with the program code may be packaged with a compatible device or provided separately from other devices (e.g., via Internet download). Any such computer readable medium may reside on or within a single computer product (e.g. a hard drive, a CD, or an entire computer system), and may be present on or within different computer products within a system or network. A computer system may include a monitor, printer, or other suitable display for providing any of the results mentioned herein to a user. Any of the methods described herein may be totally or partially performed with a computer system including one or more processors, which can be configured to perform the steps. Thus, embodiments can be directed to computer systems configured to perform the steps of any of the methods described herein, potentially with different components performing a respective steps or a respective group of steps. Although presented as numbered steps, steps of methods herein can be performed at a same time or in a different order. Additionally, portions of these steps may be used with portions of other steps from other methods. Also, all or portions of a step may be optional. Additionally, any of the steps of any of the methods can be performed with modules, circuits, or other means for performing these steps. The specific details of particular embodiments may be combined in any suitable manner without departing from the spirit and scope of embodiments of the invention. However, other embodiments of the invention may be directed to specific embodiments relating to each individual aspect, or specific combinations of these individual aspects. The above description of exemplary embodiments of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form described, and many modifications and variations are possible in light of the teaching above. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications to thereby enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. A recitation of “a”, “an” or “the” is intended to mean “one or more” unless specifically indicated to the contrary. All patents, patent applications, publications, and descriptions mentioned here are incorporated by reference in their entirety for all purposes. None is admitted to be prior art.
	abstract	Systems and methods for sterilizing a column assembly including a column having an interior containing a retaining media and a parent radionuclide retained by the retaining media, an inlet port in fluid communication with the interior of the column, and an outlet port in fluid communication with the interior of the column. The method includes sealing at least one of the inlet port and the outlet port to form a sealed column assembly such that fluid communication with the column interior though both the inlet port and the outlet port is prevented, and sterilizing the sealed column assembly to form a terminally-sterilized column assembly.
	summary
	summary
	description	The present invention relates to the efficient fabrication of semiconductor devices with accurate ultrafine design features. The present invention is particularly applicable to the efficient use of lithographic exposure devices, such as extreme ultraviolet (EUV) lithography devices, by minimizing downtime. The dimensions of semiconductor device features relentlessly plunge into the deep sub-micron range challenging conventional fabrication capabilities. As critical dimensions shrink, it becomes increasingly more difficult to achieve high dimensional accuracy in an efficient manner with high manufacturing throughput. The minimum feature size depends upon the chemical and optical limits of a particular lithography system, and the tolerance for distortions. In addition to the limitations of conventional lithography, as dimensions shrink and memory capacity increases, manufacturing costs increase, thereby requiring advances in processing aimed at the efficient use of facilities and high manufacturing throughput. In today's competitive market, a yield of at least 70% is required for profitability. It has been recently proposed to employ shorter wavelength radiation, e.g., of about 3 to 20 nm. Such radiation is conventionally termed EUV or soft X-ray. Sources include, for example, laser-produced plasma sources, discharge plasma sources, or synchrotron radiation from electron storage rings. Such EUV lithography exposure tools, however, have been problematic. A major source of concern is the contamination of the reflective optical elements during operation due to residual gases from the vacuum atmosphere. Optical reflective elements for the soft X-ray to EUV wavelength range, such as photomasks or multilayer mirrors, are required for use in EUV lithography of semiconductor components. Typical EUV lithography exposure devices have eight or more reflective optical elements. In order to achieve a sufficient overall intensity of the working radiation, the mirrors must have the highest possible reflectivities, since the overall intensity is proportional to the product of the reflectivities of the individual mirrors. These high reflectivities should be retained by the reflective optical elements if possible throughout their lifetime. Furthermore, the homogeneity of the reflectivity across the surface of the reflective optical element must be preserved for the entire lifetime. The reflectivity and the lifetime of these reflective optical elements are especially impaired by surface contamination in the form of carbon deposits and by surface oxidation during exposure to the operating wavelength. The reflective optical elements are contaminated during operation by residual gases in the vacuum atmosphere. A contamination mechanism comprises adsorption of residual gases on the surfaces of the reflective optical elements. The adsorbed gases are broken up by the high-energy photon radiation through emission of photoelectrons. When hydrocarbons are present in the residual gas atmosphere, a carbon layer is thus formed, which diminishes the reflectivity of a reflective optical element by around 1% per nm of thickness. At a partial pressure of hydrocarbons of around 10−9 mbar, a layer of 1 nm thickness will be formed already after around 20 hours. Commercial specifications for projection optics lifetime is a reflectance loss of less than 1% per surface. A 15 Å thick film of carbon in the form of graphite would reduce the reflectivity of an EUV optic by 2%. Since, for example, EUV lithography devices with a reflectivity loss of 1% per reflective optical element no longer allow the necessary production pace, this contamination layer must be removed by a cleaning process which typically takes up to 5 hours, thereby reducing manufacturing throughput. Moreover, such cleaning is likely to damage the surface of the reflective optical element, as by roughening or oxidizing the surface, thereby preventing the initial reflectivity from being regained. Conventional approaches to the carbon deposition problem also include the use of EUV imaging optics comprising multilayers of various elemental combinations deposited on glass substrates. Silicon has historically been chosen for the final capping layer because it is less susceptible to oxidation than molybdenum when exposed to air. However, silicon is susceptible to rapid EUV-induced oxidation by water vapor. Ruthenium (Ru) has shown promise as an alternative capping layer, because it is less sensitive to radiation-induced oxidation. However, Ru-capped multilayers are susceptible to carbon deposition. To ensure maximum EUV exposure, it is imperative that EUV optics be maintained as clean as possible during operation. Accordingly, a need exists for lithographic exposure tools, particularly EUV lithography exposure tools, with reduced carbon contamination on the reflective elements during use. There also exists a need for methodology enabling careful control of the hydrocarbon level such that it is sufficiently high enough to protect the fragile multilayer reflective layers from oxidation, but low enough to avoid carbon build up on the optical elements due to cracking of the hydrocarbons by EUV radiation. An advantage of the present invention is a lithographic exposure device with reduced carbon deposition on optical elements during use. Another advantage of the present invention is an EUV lithography exposure tool capable of maintaining hydrocarbon levels to avoid adverse oxidation of and adverse carbon deposition on reflective optical elements. A further advantage of the present invention is a method of reducing carbon deposition on the reflective optical elements of an EUV device. Another advantage of the present invention is a method of controlling the amount of hydrocarbons in an EUV lithography exposure device to a level sufficient to prevent oxidation of and minimize carbon deposition on reflective optical elements. Additional advantages and other features of the present invention will be set forth in the description which follows and in part will be apparent to those having ordinary skill in the art upon examination of the following or may be learned from the practice of the present invention. The advantages of the present invention may be realized and obtained as particularly pointed out in the appended claims. According to the present invention, the foregoing and other advantages are achieved in part by a lithographic exposure device comprising a hydrocarbon getter. Another advantage of the present invention is an extreme ultraviolet (EUV) lithography exposure device comprising: a primary EUV source, a reflective optical element for the soft X-ray or EUV wavelength radiation range; and a hydrocarbon getter comprising a substrate and an electron gun or a separate EUV source positioned to direct an energy beam at the substrate. A further advantage of the present invention is a method of reducing carbon deposition in a lithographic exposure device, the method comprising incorporating a hydrocarbon getter in the lithographic exposure device. Embodiments of the present invention include EUV lithography exposure devices comprising a conventional primary EUV source and at least one hydrocarbon getter comprising a substrate and a high energy source positioned to direct an energy beam at the substrate, the energy beam having sufficient strength to crack hydrocarbons in the system, e.g., a strength at least as great as the energy beam emitted by the primary EUV source. Suitable high energy sources include an electron gun and a separate EUV source. Suitable substrates include glass, metal, such as Ru, metal coated glass, and quartz crystal thickness monitors. Embodiments of the present invention include EUV lithography exposure tools comprising a residual gas analyzer for determining the hydrocarbon level in the device and a controller for controlling the electron beam current, in response to the measured thickness of the carbon deposited on a quartz crystal thickness monitor, to control the amount of hydrocarbons at a predetermined low level sufficient to prevent oxidation and adverse carbon contamination of reflective optical elements. Additional advantages of the present invention will become readily apparent to those skilled in the art from the following detailed description, wherein embodiments of the present invention are described, simply by way of illustration of the best mode contemplated for carrying out the present invention. As will be realized, the present invention is capable of other and different embodiments and its several details are capable of modifications in various obvious respects, all without departing from the present invention. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive. The present invention addresses and solves problems attendant upon the use of lithographic exposure tools, such as lithographic exposure tools that operate under a very short wavelength, e.g., soft X-ray and EUV wavelength range radiation, by minimizing and controlling carbon deposition on and preventing oxidation of reflective optical elements, thereby reducing downtime and increasing manufacturing throughput. Embodiments of the present invention include carefully controlling the partial pressure of heavy hydrocarbons in an EUV lithography exposure tool, such as at a level of about 10−9 mbar to about 10−7 mbar, so that it is high enough to prevent oxidation of the reflective optical coatings but low enough to avoid rapid build up of a carbon film thereon. Carbon contamination results from hydrocarbon cracking by EUV radiation from the primary EUV source of the exposure tool. Embodiments of the present invention include positioning a hydrocarbon getter in a conventional lithographic exposure tool, such as a conventional EUV lithography exposure tool. Embodiments of the present invention include lithographic exposure tools with at least one hydrocarbon getter, comprising a substrate and a high energy source positioned to impinge a beam having an energy sufficient to crack hydrocarbons and form a carbon film on the substrate. Suitable energy sources used in embodiments of the present invention are capable of generating an energy beam having a strength at least as great as that generated by the primary EUV source of the exposure tool, such as a separate EUV source or an electron gun, e.g., an electron gun operating at 1-2 kV. Suitable substrates for use in hydrocarbon getters according to embodiments of the present invention include glass, quartz, and quartz crystal thickness monitors, with or without a metal coating, such as a Ru coating, laminates, and metal substrates. By scavenging the hydrocarbons using a getter in accordance with embodiments of the present invention, the amount of hydrocarbons available to be cracked into carbon and form deposits on the reflective optical elements is significantly reduced. Embodiments of the present invention also include EUV lithography exposure tools with a hydrocarbon getter comprising an electron gun and a quartz crystal thickness monitor, or a metal, e.g. Ru, coated quartz crystal thickness monitor. In such tools, a residual gas analyzer is incorporated to determine the amount of hydrocarbons in the system, and a controller is provided. In response to the rate of carbon deposited on the quartz crystal thickness monitor, the controller controls the electron beam current such that the amount of hydrocarbons in the system, as determined by the residual gas analyzer, is maintained at a predetermined low, but finite level, such as at a partial pressure of about 10−9 mbar to about 10−7 mbar. In this way, the amount of hydrocarbons is maintained at a level sufficient to prevent oxidation of the delicate reflective optical elements, but low enough to prevent carbon coatings from rapidly building up thereon, thereby significantly reducing downtime and increasing manufacturing throughput. A hydrocarbon getter in accordance with an embodiment of the present invention is schematically illustrated in FIG. 1 and comprises an electron gun that operates at 1-2 kV. The electron gun is positioned to impinge electrons directly on the surface of a substrate, such as comprising a glass substrate 10 with a layer of Ru deposited thereon, as at a thickness of about 2 nm to about 200 nm. Hydrocarbons (HxCy) in the system, particularly heavy hydrocarbons, e.g., with masses between 44 and 200 atomic mass units (AMU), in the vicinity of the substrate are cracked by the electrons from the electron gun, thereby forming a carbon film on the substrate. The hydrocarbons cracked into carbon and deposited on the substrate are unavailable to be cracked by EUV radiation generated by the primary EUV source of the lithographic exposure tool to deposit carbon on reflective optical elements. In FIG. 2 there is schematically illustrated the interior of an EUV lithography exposure tool comprising an EUV optic with EUV radiation impinging thereon. Two electron beam hydrocarbon getters, such as that illustrated in FIG. 1, are positioned in sufficient proximity to the EUV optic such that carbon would be preferentially deposited on the substrates of the getters, thereby significantly reducing carbon deposition on the EUV optic. In embodiments of the present invention, a hydrocarbon getter can be positioned at a distance of about 1 cm to about 10 cm from the EUV optic. In another embodiment of the present invention, as schematically illustrated in FIG. 3, an EUV lithography exposure tool is provided with a hydrocarbon getter comprising an electron gun positioned to impinge electrons on a substrate comprising an optional Ru coating 30, as at a thickness of about 2 nm to about 200 nm, on a quartz crystal thickness monitor 31. The rate of carbon deposition on the Ru coating is recorded by the quartz crystal thickness monitor. A controller monitors the rate of carbon deposition and controls the electron beam current such that the hydrocarbon level in the system is maintained within a predetermined low level, as measured by a residual gas analyzer (not shown for illustrative convenience). Typically, the hydrocarbon level is maintained at a partial pressure of about 10−9 mbar to about 10−7 mbar, which is sufficiently high to prevent oxidation of the delicate optical elements but sufficiently low to minimize carbon deposition thereon, thereby extending the useful life of the tool and avoiding frequent downtime for cleaning. In accordance with embodiments of the present invention, EUV induced carbon deposition on the EUV optics is minimized and controlled by employing a hydrocarbon getter. Radiation-induced chemical phenomena at the surfaces of EUV optics are known to be qualitatively the same whether the incident radiation is EUV photons or 1-2 keV electrons as long as the number of secondary electrons generated is similar. For example, incident electron current densities of 5 μA/mm2 at 2 keV beam energy have been shown to generate ˜5 μA/mm2 of secondary electrons. This is about the same as the secondary photoemission current observed when an EUV optic is exposed to 13.4 nm radiation at a power density of ˜10 mW/mm2. A power density of ˜10 mW/mm2 lies at the high end of the range of power densities that will be present in a commercial EUVL exposure tool. Therefore, the use of a hydrocarbon getter in accordance with embodiments of the present invention mimics hydrocarbon cracking by EUV photons, reducing the amount of hydrocarbons available for deposition on delicate optical elements of the EUV tool. Accordingly, hydrocarbon getters in accordance with embodiments of the present invention include energy sources capable of generating a beam having an energy sufficient to crack heavy hydrocarbons to deposit carbon, such as an energy of 1-2 KeV or at a power density of at least ˜10 mW/mm2. The present invention enables the efficient use of lithographic exposure devices, particularly EUV lithography exposure devices, by providing a getter to scavenge hydrocarbons, thereby preventing excess carbon deposition on optical elements. Embodiments of the present invention enable the use of EUV lithography exposure tools for longer periods of time before the need for in-situ cleaning, thereby extending the useful lifetime of the optical elements and increasing manufacturing throughput. Embodiments of the present invention enable control of the amount of hydrocarbons in an EUV lithography exposure tool at a level sufficient to prevent oxidation of reflective optical elements and sufficient to minimize carbon deposition thereon. The present invention enables the fabrication of semiconductor chips comprising devices with accurately formed features in the deep sub-micron range, in an efficient manner at high manufacturing throughput and high yield. The present invention enjoys industrial utility in fabricating semiconductor chips comprising any of various types of semiconductor devices, including semiconductor memory devices, such as erasable, programmable, read-only memories (EEPROMs), and flash erasable programmable read-only memories (FEPROMs). In the preceding description, the present invention is described with reference to specifically exemplary embodiments thereof. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of the present invention, as set forth in the claims. The specification and drawings are, accordingly, to be regarded as illustrative and not as restrictive. It is understood that the present invention is capable of using various other combinations and embodiments and is capable of any changes or modifications within the scope of the inventive concept as expressed herein.
	description	FIG. 1 is a schematic, partial sectional view, with parts cut-away, of a reactor pressure vessel (RPV) 20 for a boiling water reactor. RPV 20 has a generally cylindrical shape and is closed at one end by a bottom head and at its other end by removable top head (not shown). A top guide (not shown) is spaced above a core plate 22 within RPV 20. A shroud 24 surrounds core plate 22 and is supported by a shroud support structure 26. An annulus 28 is formed between shroud 24 and side wall 30 of RPV 20. An inlet nozzle 32 extends through side wall 30 of RPV 20 and is coupled to a jet pump assembly 34. Jet pump assembly 34 includes a thermal sleeve 36 which extends through nozzle 32, a lower elbow (only partially visible in FIG. 1), and a riser pipe 38. Riser pipe 38 extends between and substantially parallel to shroud 24 and RPV side wall 30. A riser brace 40 stabilizes riser pipe 38 within RPV 20. Jet pump assembly 34 also includes inlet mixers 42 connected to riser pipe 38 by transition assembly 44. Inlet mixers 42 are coupled to corresponding diffusers 46 by slip joints 48. Each diffuser 46 includes four guide ears 50 equally spaced around diffuser 46 at slip joint 48. FIG. 2 is a top sectional view of jet pump 34 with a seal assembly 52 attached in accordance with an embodiment of the present invention. FIG. 3 is a front sectional view of jet pump 34 and seal assembly 52. Referring to FIGS. 1 and 2, seal apparatus 52 includes a split seal ring 54 and a segmented diaphragm spring 56 engaging split seal ring 54 at an inner circumference 58 of diaphragm spring 56. Diaphragm spring 56 has a first surface 60 and a second surface 62, and includes a plurality of latch assemblies 64 spaced circumferentially around an outer circumference 66, with each latch assembly 64 configured to engage a diffuser guide ear 50. A seal ring engagement portion 68 depends from second surface 62 of diaphragm spring 56 and extends around inner circumference 58. Seal engagement portion 68 is configured to engage seal ring 54. A support portion 70 depends from second surface 62 of diaphragm spring 56 and extends around outer circumference 66. A plurality of slots 72 extend from inner circumference 58 to support portion 70 of diaphragm spring 56. Slots 72 are spaced circumferentially around inner circumference 58. Each latch assembly 64 includes a substantially L-shaped latch block 74 coupled to first surface 60 of diaphragm spring 56, and a latch bolt 76. An opening 78 extends through upper latch block 74. Latch bolt 76 extends through opening 78 and extends through a corresponding latch bolt opening 80 in support portion 70 of diaphragm spring 56. Each latch bolt 76 includes a head 82 and a plurality of ratchet teeth 84 spaced around a periphery of latch bolt head 82. A locking spring 86 is coupled to upper latch block 74 adjacent opening 78. A retention stub 88 extends from one side of locking spring 86. Retention stub 88 is sized to engage ratchet teeth 84 to lock latch bolt 76 in place and prevent latch bolt 76 from loosening. Upper latch block 74 also includes a release opening 90 located adjacent locking spring 86. Release opening 90 is sized to receive a release tool (not shown) which moves locking spring 86 to disengage retention stub 88 from ratchet teeth 84 to enable latch bolt 76 to be loosened. Referring also to FIG. 4, latch assembly 64 further includes a latch arm 92 coupled to latch bolt 76. Latch arm 92 includes a slot 94 sized to receive a diffuser guide ear 50. Latch arm 92 includes a first engagement finger 96 and a second engagement finger 98 on opposite sides of slot 94. First engagement finger 96 includes an angled end portion 100 to permit latch arm 92 to swing from an open position 102 to a closed or engaged position 104 without guide ear 50 interfering with first engagement finger 96 by contacting an outer surface 106 of first engagement finger 96. A threaded latch bolt opening 108 extends through latch arm 92. Latch bolt 76 extends through and threadedly engages opening 108. A bolt retention collar 110 is attached to latch bolt 76 to retain latch bolt 76 in latch bolt opening 80 in support portion 70 of diaphragm spring 56. Seal apparatus 52 is installed on slip joint 48 by positioning split ring seal 54 and diaphragm spring 56 on an end 112 of diffuser 46 with a spring slot 72 engaging each diffuser guide ear 50. Latch bolt 76 of each latch assembly 64 is tightened so that latch arms 92 swing into position and engage a corresponding guide ear 50. Inlet mixer 42 is installed through split ring seal 54 and diaphragm spring 56 and into diffuser 46 to form slip joint 48. Latch bolt 76 is tightened further to capture the latch arm slot 94 against guide ear 50 to engage seal engagement portion 68 of diaphragm spring 56 with seal ring 54. An elastic deflection of diaphragm spring 56 maintains a sealing force on ring seal 54 while accommodating the minor thermal differential changes in component dimensions during operation of the reactor. Latch bolt 76 is locked in place by locking spring 86 engaging ratchet teeth 84 of clamp bolt head 82. The above described seal apparatus 52 restricts leakage flow between inlet mixer 42 and diffuser 46 at slip joint 48 to prevent oscillating motion and to eliminate high level flow induced vibration. Additionally, the wedging action of seal 54 in the slip joint opening provides a rigid resistance to oscillating motion. 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.
	summary
049960199	abstract	In order to ensure a good seal and a good resistance to shocks and corrosion, without increasing their cost, radioactive waste storage containers are completely made from metal fiber-reinforced concrete. This material is used for producing by molding a drum (210) and a cover (212), as well as a keying joint (224) by which the cover is fixed to the drum. At least one dovetail keying groove is formed in the junction zone between the drum and the cover. Advantageously, a filling material of the same nature as that in which is formed the container is injected into the latter, so as to form a homogeneous block.
051715147	claims	1. An apparatus for sealing a conduit having a circumferential inside surface, comprising: (a) a bracket having a circumferential outside surface for engaging the circumferential inside surface of the conduit, said bracket having an opening therethrough and a slot therein in communication with the opening; and (b) means disposed in the opening of said bracket for sealingly plugging the opening, said plugging means operable to engage the slot of said bracket for connecting said plugging means to said bracket, said plugging means including: (i) a first plate member disposed in the opening of said bracket, said first plate member having a threaded first bore and a channel therethrough; (ii) a second plate member mounted on said bracket and disposed coaxially adjacent said first plate member for sealably covering the opening of said bracket, said second plate member having a threaded second bore therethrough; (iii) a threaded shaft threadably engaging the threaded first bore of said first plate member and the threaded second bore of said second plate member for connecting said first plate member to said second plate member; (iv) an actuator connected to said shaft; said actuator having a cam surface thereon; (v) an arm connected to said actuator and slidably extending through the channel of said first plate member, said arm having an end portion sized to engage the slot of said bracket; and (vi) a cam attached to said arm for slidably engaging the cam surface of said actuator. (a) a generally cylindrical bracket having a circumferential outside surface for matingly engaging the circumferential inside surface of the conduit and having a bearing surface thereon, said bracket having an opening longitudinally therethrough and a slot transversely therein in communication with the opening; and (b) a plug matingly disposed in the opening of said bracket for sealably plugging the opening, said plug operable to engage the slot of said bracket for connecting said plug to said bracket, whereby the opening is sealed as said plug sealingly plugs the opening and is connected to said bracket, said plug further including: (i) a first plate member disposed in the opening of said bracket, said first plate having a threaded generally cylindrical longitudinal first bore and a generally cylindrical transverse channel therethrough; (ii) a second plate mounted on the bearing surface of said bracket and coaxially disposed in the opening of said bracket and disposed adjacent said first plate for sealably covering the opening of said bracket, said second plate having a threaded generally cylindrical second bore longitudinally therethrough; and (iii) a generally cylindrical threaded shaft threadably engaging the threaded first bore of said first plate and the threaded second bore of said second plate for threadably connecting said first plate to said second plate; (iv) an actuator connected to said shaft, said actuator having a generally arcuate hole therethrough defining a cam surface; and (v) a generally cylindrical arm slidably extending through the channel of said first plate, said arm having a first end portion connected to said actuator and a second end portion sized to engage the slot of said bracket; and (vi) a rounded cam integrally attached to the first end portion of said arm for slidably matingly engaging the cam surface defined by the hole of said actuator, whereby the cam surface of said actuator slidably engages said cam as said actuator is actuated, whereby said arm slides in the channel as the cam surface slidably engages said cam, and whereby the second end portion of said arm engages the slot of said bracket as said arm slides in the channel. (a) a generally cylindrical bracket mounted on the shoulder defined by the inside surface of the nozzle, said bracket having a circumferential outside surface for sealably matingly engaging the circumferential inside surface of the nozzle, said bracket having a plurality of generally arcuate openings longitudinally therethrough and a plurality of generally rectangular slots transversely therein in communication with each opening, said bracket having a bearing surface thereon; and (b) a unitary generally arcuate plug matingly disposed in each opening of said bracket for sealably plugging each opening, at least one of said plugs operable to engage the slots of said bracket for connecting said plug to said bracket, whereby the nozzle is sealed as each plug sealably plugs each opening and is connected to said bracket, each of said plugs including: (a) a wing nut having a threaded bore longitudinally therethrough threadably engaging the third threaded portion of said shaft, said wing nut having a generally arcuate hole transversely therethrough defining a cam surface; and (b) a generally cylindrical arm slidably disposed in each channel of said first plate, said arm having a first end portion for slidably engaging the cam surface of said wing nut and having a second end portion sized to matingly engage the slot of said bracket. (i) whereby said wing nut threadably traverses along the longitudinal axis of said shaft as said shaft is rotated; (ii) whereby the cam surface of said wing nut slidably engages said cam as said wing nut traverses along the longitudinal axis of said shaft; (iii) whereby said arm slides in the channel as the cam surface slidably engages said cam; and (iv) whereby the second end portion of said arm engages the slot of said bracket as said arm slides in the channel. (a) a first elongated link member having a first end portion connected to said shaft and having a second end portion; (b) a second elongated link member having a first end portion pivotally connected to the second end portion of said first link member and having a second end portion pivotally connected to said arm for sliding said arm in the channel as said shaft is rotated. 2. The apparatus according to claim 1, further comprising a seal interposed between said second plate member and said bracket for forming a seal therebetween. 3. The apparatus according to claim 2, wherein said first plate member comprises a bushing disposed in the channel of said first plate member, said bushing surrounding said arm for providing a low-friction sliding surface for said arm. 4. The apparatus according to claim 1, wherein said actuator is a link assembly. 5. The apparatus according to claim 1, further comprising anti-rotation means engaging said first plate member and said second plate member for maintaining said first plate member and said second plate member in relative alignment. 6. An apparatus for sealing a conduit having a circumferential inside surface, comprising: 7. The apparatus according to claim 6, further comprising a seal interposed between said second plate and said bracket for forming a seal therebetween. 8. The apparatus according to claim 7, further comprising a hollow generally cylindrical bushing disposed in the channel of said first plate, said bushing surrounding said arm for providing a low-friction wear surface so that said arm slides in said bushing with minimal friction. 9. An apparatus according to claim 8, further comprising a vent in communication with the opening defined by said bracket for venting gas from the opening, said vent being openable for venting the gas and closable for sealing the opening. 10. The apparatus according to claim 6, wherein said actuator is a link assembly, said link assembly having a portion thereof connected to said shaft and another portion thereof pivotally connected to said arm for sliding said arm in the channel of said first plate so that the second end portion of said arm engages the slot of said bracket. 11. The apparatus according to claim 6, further comprising an elongated anti-rotation pin extending outwardly from said first plate and engaging said second plate for maintaining said first plate and said second plate in relative alignment. 12. In a nuclear steam generator having a primary nozzle, an apparatus for sealing the primary nozzle, the primary nozzle having a circumferential inside surface, the inside surface defining a depending annular shoulder therearound, comprising: 13. The apparatus according to claim 12, wherein said arm comprises a rounded cylindrical cam integrally attached to the first end portion of said arm for slidably matingly engaging the cam surface defined by the hole of said wing nut, 14. The apparatus according to claim 13, further comprising a fluid impermeable seal integrally attached to said second plate, said seal interposed between said second plate and said bracket for forming a seal therebetween, so that the opening of said bracket is sealed thereby. 15. The apparatus according to claim 14, wherein said seal is elastomeric rubber resistant to nuclear radiation. 16. The apparatus according to claim 14, further comprising a hollow generally cylindrical wear-resistant bushing disposed in the channel of said first plate, said bushing surrounding said arm for providing a low-friction wear-resistant surface so that said arm slides in said bushing with minimal friction. 17. The apparatus according to claim 16, further comprising a vent in communication with the opening defined by said bracket for venting radioactive gas from the opening, said vent being openable for venting the opening. 18. The apparatus according to claim 17, wherein said vent is a valve for venting the opening defined by said bracket as said valve is opened and for sealing the opening defined by said bracket as said valve is closed. 19. The apparatus according to claim 12, wherein at least one of said plugs further comprises: 20. The apparatus according to claim 12, further comprising a plurality of elongated generally cylindrical anti-rotation pins attached to said first plate and outwardly extending therefrom, said pins engaging said second plate for maintaining said first plate and second plate in relative alignment.
	summary
	claims	1. A nuclear power generating facility having a containment for housing a nuclear reactor for confining radiation leaked from the nuclear reactor, the containment having a ventilation outlet for providing a controlled release for an atmospheric pressure buildup within the containment in event the pressure of an atmospheric effluent within the containment is built up to a level that exceeded a preselected value, including a filter comprising:a filter vessel having an input nozzle connected to the ventilation outlet;a liquid occupying a portion of a lower interior of the filter vessel and configured to function as a scrubber for the atmospheric effluent;an inlet conduit in fluid communication with the inlet nozzle and extending into the lower interior of the filter vessel;a manifold connected to the inlet conduit and extending into the lower portion of the filter vessel, the manifold including a plurality of outlets and designed to operate with the outlets respectively releasing a portion of the containment atmospheric effluent under a pool of the liquid contained within the filter vessel;a first set of a plurality of fiber filters, each fiber filter being submerged in the liquid and having substantially a first density of fibers for filtering the atmospheric effluent exhausted through the corresponding outlet in the manifold with each of the fiber filters in the first set connected to and in fluid communication with one of the manifold outlets and configured, in a steady state operation of the filter, so that the containment atmospheric effluent passes through at least a portion of the fibers before the containment atmospheric effluent contacts the liquid; anda filter vessel outlet in fluid communication with the interior of the filter vessel and operable to exhaust the filtered containment atmospheric effluent to an outside atmosphere exterior of the containment. 2. The nuclear power generating facility of claim 1 wherein the filter vessel is inerted with nitrogen. 3. The nuclear power generating facility of claim 1 wherein said liquid comprises water. 4. The nuclear power generating facility of claim 1 including sodiumthiosulphate dissolved within the liquid. 5. The nuclear power generating facility of claim 1 including a demister supported above the pool of liquid for separating out any moisture from an exhaust fraction of the filtered containment atmospheric effluent. 6. The nuclear power generating facility of claim 1 including a second set of a plurality of fiber filters extending from a second manifold which is connected to the filter vessel outlet. 7. The nuclear power generating facility of claim 6 wherein the second set of the plurality of fiber filters has a greater density of fibers than the first set of fiber filters. 8. The nuclear power generating facility of claim 7 wherein the second set of fiber filters comprise metal fibers. 9. The nuclear power generating facility of claim 1 wherein the first set of fiber filters comprise metal fibers. 10. The nuclear power generating facility of claim 1 wherein the filter vessel is a pressure vessel including apparatus for maintaining the filter vessel interior at a pressure above atmospheric pressure. 11. The nuclear power generating facility of claim 1 wherein the manifold extends into the lower portion of the filter vessel at an acute angle to a central axis of the filter vessel. 12. The nuclear power generating facility of claim 11 wherein the manifold extends into the lower interior of the filter vessel, configured as an inverted “V” having a downward leg extending from each side of an apex with the outlets extending from at least one of the legs. 13. The nuclear power generating facility of claim 12 wherein the inlet conduit is coupled to the manifold at the apex. 14. The nuclear power generating facility of claim 2 wherein each of the downward extending legs has the outlets extending therefrom. 15. The nuclear power generating facility of claim 12 wherein the outlets extend upwardly from the extending legs. 16. A filter for filtering an effluent, comprising:a vessel having an input nozzle;a liquid occupying a portion of a lower interior of the vessel and configured to function as a scrubber for the effluent;an inlet conduit in fluid communication with the inlet nozzle and extending into the lower interior of the vessel;a manifold connected to the inlet conduit and extending into the lower portion of the vessel; the manifold including a plurality of outlets and designed to operate with the outlets respectively releasing a portion of an effluent to be filtered, under a pool of the liquid contained within the vessel;a first set of a plurality of fiber filters, each fiber filter being submerged in the liquid and having substantially a first density of fibers for filtering the effluent exhausted through the corresponding outlet in the manifold with each of the fiber filters in the first set connected to and in fluid communication with one of the manifold outlets and configured, in a steady state operation of the filter, so that the effluent passes through at least a portion of the fibers before the effluent contacts the liquid; anda vessel outlet in fluid communication with the interior of the vessel and operable to exhaust the filtered effluent to an outside atmosphere. 17. The filter of claim 16 including a demister supported above the pool of liquid for separating out any moisture from an exhaust fraction of the filtered effluent. 18. The filter of claim 16 wherein the manifold extends into the lower interior of the vessel at an acute angle to a central axis of the vessel and the manifold is configured as an inverted “V” having a downward leg extending from each side of an apex with the outlets extending from at least one of the legs. 19. The filter of claim 16 including a second set of a plurality of fiber filters extending from a second manifold which is connected to the vessel outlet wherein the second set of the plurality of fiber filters has a greater density of fibers than the first set of fiber filters.
051749459	summary	BACKGROUND OF THE INVENTION 1. Field of the Invention The invention is in the field of fusion power generators, particularly those utilizing fusion reactors of the magnetic confinement type. 2. Description of the Prior Art Prior art concepts with regard to utilization of fusion energy for the economic production of power have been premised upon an ultimate design of a large scale reactor able to produce the desired power and lasting a sufficiently long time to justify the large capital investment required to build the reactor. The economics of a large capital investment with a long reactor lifetime have been carried over from the fission reactor field as an inherent basis in the design of economic fusion power plants. Consequently, plasma temperatures and densities have been parameterized to yield a maximum wall loading of the first wall (vacuum wall surrounding the plasma) consistent with durability of wall materials and a long replacement time which is economically acceptable. Typically, a maximum wall loading of 1-3 MW/m.sup.2 has been thought reasonable with a minimum replacement time of approximately five years. Consistent with the projected long life of the fusion reactor, the plasma core has traditionally been made large so as to allow large power output with low energy loadings on the first wall as well as for reasons of plasma confinement in the regimes of traditional interest. Furthermore, the plasma core has traditionally been surrounded directly with a thick material blanket region to absorb the plasma-generated neutron energy as well as to protect the large and expensive magnetic field windings surrounding the blanket. These large field windings, required to confine plasma in the plasma core, must be large enough to surround the plasma core. Traditionally, superconducting magnets have been utilized in order to reduce the power required to drive the magnetic coils, and the blanket thus served to remove the coils from the regime of high neutron fluxes and associated radiation damage to which the superconductors are susceptible. Such superconducting magnets have a limited magnetic field capability of between approximately 80 and 120 kilogauss. The maximum permissible density and temperature of the plasma is in turn dictated by the strength of the magnetic field possible which, because of the foregoing considerations has been limited to the maximum strength available from the superconducting magnets. Thus, traditional future fusion device concepts have involved large plasma volumes, thick blankets of large volume, low first wall loadings, and the use of large, expensive superconducting magnets placed outside the regions of the blanket, plasma core, and any added auxiliary shielding. In utilizing large volume experimental reactors of the tokamak-type, and in the conceptual design of practical large volume toroidal reactors, ohmic heating inherently plays a negligible role in the process of raising the plasma temperatures to values of thermonuclear interests. This is true because the current density which can be induced in any toroidal plasma configuration is proportional to the magnetic field divided by the major radius of the torus. For the fields attainable by superconducting magnets and the dimensions of traditionally envisioned toroidal devices, the current density is insufficient to yield significant ohmic heating of the plasma. Thus, in both the experimental and conceptual designs large sources of energetic beams of neutral particles have been utilized to provide power to the plasma on the order of ten megawatts. Neutral beam injection techniques require the utilization of large access ports to the plasma through the surrounding magnetic structure thus adding to the cost and complexity of any practical fusion power plant. Additionally, in order to ensure proper beam penetration to the center of the plasma column, operation of neutral beam injection devices has been limited to plasma densities not exceeding 10.sup.14 /cm.sup.3. As experimental fusion devices, blankets have typically not been employed inasmuch as they are unnecessary to study many of the basic physical processes involved in the plasma such as plasma fusion ignition, confinement, plasma heating and fusion reaction studies. The tokamak has provided an experimental tool for testing the feasibility of plasma confinement and has been the subject of extensive experimentation, e.g., see "The Tokamak Approach in Fusion Research" by Bruno Coppi et al, Scientific American, July 1972, U.S. Pat. No. 3,778,343 and "Tokamak Experimental Power Reactor Conceptual Design", Vols. 1 & 2, ANL/CTR-76-3 (August 1976), all of which documents are incorporated hereby by reference. One particular tokamak device, the Alcator, has been designed to achieve large plasma currents with high toroidal magnetic field strengths. Typically, plasma currents on the order of 100 kiloamps with field strengths up to 82 kilogauss have been obtained. In such experimental devices, plasmas with densities up to 9.times.10.sup.14 particles per cubic centimeter with temperatures up to 1 keV have been contained. However, the Alcator approach is not typical of the majority of prior art devices which have focused on toroidal devices of much lesser density, larger dimension, smaller magnetic fields and which require extensive auxiliary heating (generally by neutral beam injection) to strive for plasma ignition temperatures. The approach of a very high yield, high density and a small compact device such as the Alcator has been considered in the prior art as limited to merely academic interest for purposes of physics studies of plasma behavior but has not been considered of interest for future applications to practical fusion power production. Another experimental area that has been developed for the magnetic confinement of thermonuclear plasma is embodied in the stellarator concept. While in the tokamak, the confining magnetic field is partially produced by external coils and partially by the current induced in the plasma, in a stellarator, the confining field is produced only by external coils. Both the tokamak and the stellarator, however, may be considered forms of a toroidal plasma confinement device. SUMMARY OF THE INVENTION It is an object of the invention to overcome the disadvantages of the prior art by providing a controlled nuclear fusion device for power generation. Another object of the invention is to provide a modular fusion reactor system wherein a plurality of fusion power cores, each of relatively small size and low cost, are energized to provide a power system. Energy from the fusion power cores is absorbed in the core structure and within a surrounding blanket, and the cores themselves may be individually removed from the blanket and replaced by new cores as the cores deteriorate from high radiation flux damage. Another object of the invention is to achieve ignition in a fusion power reactor by employing staged fuel injection and charged particle heating from fusion reactions to overcome bremsstrahlung losses and to provide heating of additional fuel fed into the plasma. The additional fuel fed into the plasma raises the plasma density such that the reaction rate increases to produce even more charged particle heating to provide the desired plasma temperatures for ignition. It is another object of this invention to provide a power generating system utilizing a plurality of fusion power cores, each of the toroidal-type and driven to ignition by controlling the plasma density within the core. At low plasma densities, ohmic heating raises the temperature of the plasma to allow charged particle heating to balance bremsstrahlung losses. With further feeding of fuel into the plasma, excess charged particle heating and ohmic heating increase the temperature of the "cold" incoming gas to provide a higher density "hot" plasma. The higher resulting density increases the charged particle production rate such that charged particle heating raises the temperature of the plasma to ignition temperatures. Further charged particle heating and increases in plasma density provide an optimum power generating regime for the fusion device. In accordance with the principles of the invention, a fusion power device is provided and comprises a plasma containment means for containing a fusible plasma within a region and a blanket means which surrounds a substantial portion of the containment means. The plasma containment means is separable from the blanket means and may be replaced upon excessive radiation damage by a new or refabricated containment means. Means are also provided for feeding the fusible fuel into the containment means for forming the plasma. The plasma density may be varied by controlling the amount of fusible fuel fed into the plasma thereby permitting charged particle heating of the plasma and operation of the fusion power device in a power producing regime of temperature and density. Thermal energy extraction means are provided for extracting energy from the plasma containment means and/or the blanket means, and means are provided for converting the extracted thermal energy into electrical energy. In accordance with the teachings of the invention, there is provided a method of igniting a thermonuclear fusible plasma in a fusion device of a toroidal magnetically confined configuration by introducing a fusible fuel into the toroidal region for generating a relatively low density plasma therefrom, generating magnetic fields for confining the plasma, heating the plasma to produce fusion reactions while maintaining a low plasma density so as to permit charged particle heating from the fusion reactions to overcome bremsstrahlung losses and introducing additional fusible fuel into the plasma while continuing to heat the plasma. The resulting increased plasma density produces a higher reaction rate such that charged particle heating from the fusion reactions balances energy losses from radiation and particle thermal conductivity. The disposable and/or recyclable characteristic of the considered fusion power core makes the remote handling and maintenance system for it considerably simple and less expensive than those envisioned for a conventional large tokomak reactor where the removal and replacement of heavy and interconnected components is involved. The ability to place an easily accessible blanket at the outside of the fusion power core without the encumberance of a surrounding magnetic coil system makes it possible to adopt the simplest and least expensive system to breed Tritium. The absence of a need for easy access to the inside components of the fusion power core makes it possible to adopt a tight aspect ratio toroidal configuration. This feature coupled with the effects of adopted auxiliary heating systems that tend to produce well distributed plasma current densities, by enhancing the temperature at the outer edge of the plasma column, makes it possible to operate the plasma device with a relatively low safety margin against macroscopic instabilities. This is equivalent to a high degree of utilization of the confining magnetic field. The small size and relatively low weight of the fusion core make it suitable to develop it, unlike the envisioned large size tokomaks, into one of the elements of a power plant to propel a ship or any other suitable type of vehicle. A choice of the appropriate structural materials of the fusion power core can be made with the objective to decrease their radio-activation to a minimum. For example aluminum based metal can be considered for this purpose.
	description	This application claims priority to U.S. Provisional Patent Application Ser. No. 62/331,611, filed May 4, 2016, the disclosure of which is hereby incorporated by reference in its entirety. The field of the disclosure relates generally to radionuclide generators and, more particularly, to systems and methods for sterility testing of radionuclide generator column assemblies. Radioactive material is used in nuclear medicine for diagnostic and therapeutic purposes by injecting a patient with a small dose of the radioactive material, which concentrates in certain organs or regions of the patient. Radioactive materials typically used for nuclear medicine include Technetium-99m (“Tc-99m”), Indium-111m (“In-111”), Thallium-201, and Strontium-87m, among others. Such radioactive materials may be produced using a radionuclide generator. Radionuclide generators generally include a column that has media for retaining a long-lived parent radionuclide that spontaneously decays into a daughter radionuclide that has a relatively short half-life. The column may be incorporated into a column assembly that has a needle-like outlet port that receives an evacuated vial to draw saline or other eluant liquid, provided to a needle-like inlet port, through a flow path of the column assembly, including the column itself. This liquid may elute and deliver daughter radionuclide from the column and to the evacuated vial for subsequent use in nuclear medical imaging applications, among other uses. Prior to use in medical applications, radionuclide generators are sterilized such that when sterile eluant is eluted through the device, the resulting elution is also sterile and suitable for injection into a patient. Additionally, column assemblies of radionuclide generators intended for use in the medical industry generally undergo sterility testing to ensure the column assemblies are sterile and suitable for producing sterile, injectable elutions. At least some known methods of sterility testing column assemblies require an extended period of time between collection and processing of a sterility test sample, and/or excessive handling of a vial in which an elution sample is collected for use in sterility testing. These circumstances may result in false negative results and false positive results. Accordingly, a need exists for improved systems and methods for sterility testing radionuclide generators. This Background section is intended to introduce the reader to various aspects of art that may be related to various aspects of the present disclosure, which are described and/or claimed below. This discussion is believed to be helpful in providing the reader with background information to facilitate a better understanding of the various aspects of the present disclosure. Accordingly, it should be understood that these statements are to be read in this light, and not as admissions of prior art. In one aspect, a method includes sterilizing a column assembly with a sterilizer. The column assembly includes a column having a parent radionuclide contained therein. The method further includes transferring the column assembly from the sterilizer to a first clean room environment, transferring the column assembly from the first clean room environment to a second clean room environment, and collecting a sterility test sample from the column assembly within the second clean room environment. In another aspect, a system for producing radionuclide generators includes a sterilization station including at least one sterilizer, a radiation containment chamber adjoining the sterilization station, and an isolator connected to the radiation containment chamber. The radiation containment chamber encloses a first clean room environment, and includes an unloader for removing a radionuclide generator column assembly from the sterilizer. The isolator encloses a second clean room environment, and includes a sterility test sample collection system for collecting a sterility test sample from the column assembly. In yet another aspect, a method includes transferring a column assembly from a radionuclide generator production line to an isolator, collecting a sterility test sample from the column assembly within the isolator, and returning the column assembly to the radionuclide generator production line. Various refinements exist of the features noted in relation to the above-mentioned aspects. Further features may also be incorporated in the above-mentioned aspects as well. These refinements and additional features may exist individually or in any combination. For instance, various features discussed below in relation to any of the illustrated embodiments may be incorporated into any of the above-described aspects, alone or in any combination. Corresponding reference characters indicate corresponding parts throughout the several views of the drawings. FIG. 1 is a schematic view of a system 100 for manufacturing radionuclide generators. The system 100 shown in FIG. 1 may be used to produce various radionuclide generators, including, for example and without limitation, Technetium generators, Indium generators, and Strontium generators. The system 100 of FIG. 1 is particularly suited for producing Technetium generators. A Technetium generator is a pharmaceutical drug and device used to create sterile injectable solutions containing Tc-99m, an agent used in diagnostic imaging with a relatively short 6 hour radiological half-life, allowing the Tc-99m to be relatively quickly eliminated from human tissue. Tc-99m is “generated” via the natural decay of Molybdenum (“Mo-99”), which has a 66 hour half-life, which is desirable because it gives the generator a relatively long two week shelf life. During generator operation (i.e., elution with a saline solution), Mo-99 remains chemically bound to a core alumina bed (i.e., a retaining media) packed within the generator column, while Tc-99m washes free into an elution vial, ready for injection into a patient. While the system 100 is described herein with reference to Technetium generators, it is understood that the system 100 may be used to produce radionuclide generators other than Technetium generators. As shown in FIG. 1, the system 100 generally includes a plurality of stations. In the example embodiment, the system 100 includes a cask loading station 102, a formulation station 104, an activation station 106, a fill/wash station 108, an assay/autoclave loading station 110, an autoclave station 112, an autoclave unloading station 114, a quality control testing station 116, a shielding station 118, and a packaging station 120. The cask loading station 102 is configured to receive and handle casks or containers of radioactive material, such as a parent radionuclide, and transfer the radioactive material to the formulation station 104. Radioactive material may be transported in secondary containment vessels and flasks that need to be removed from an outer cask prior to formulation. The cask loading station 102 includes suitable tooling and mechanisms to extract secondary containment vessels and flasks from outer casks, as well as transfer of flasks to the formulation cell. Suitable devices that may be used in the cask loading station 102 include, for example and without limitation, telemanipulators 122. At the formulation station 104, the raw radioactive material (i.e., Mo-99) is quality control tested, chemically treated if necessary, and then pH adjusted while diluting the raw radioactive material to a desired final target concentration. The formulated radioactive material is stored in a suitable containment vessel (e.g., within the formulation station 104). Column assemblies containing a column of retaining media (e.g., alumina) are activated at the activation station 106 to facilitate binding of the formulated radioactive material with the retaining media. In some embodiments, column assemblies are activated by eluting the column assemblies with a suitable volume of HCI at a suitable pH level. Column assemblies are held for a minimum wait time prior to charging the column assemblies with the parent radionuclide. Following activation, column assemblies are loaded into the fill/wash station 108 using a suitable transfer mechanism (e.g., transfer drawer). Each column assembly is then charged with parent radionuclide by eluting formulated radioactive solution (e.g., Mo-99) from the formulation station 104 through individual column assemblies using suitable liquid handling systems (e.g., pumps, valves, etc.). The volume of formulated radioactive solution eluted through each column assembly is based on the desired Curie (Ci) activity for the corresponding column assembly. The volume eluted through each column assembly is equivalent to the total Ci activity identified at the time of calibration for the column assembly. For example, if a volume of formulated Mo-99 required to make a 1.0Ci generator (at time of calibration) is ‘X’, the volume required to make a 19.0Ci generator is simply 19 times X. After a minimum wait time, the charged column assemblies are eluted with a suitable volume and concentration of acetic acid, followed by an elution with a suitable volume and concentration of saline to “wash” the column assemblies. Column assemblies are held for a minimum wait time before performing assays on the column assemblies. The charged and washed column assemblies are then transferred to the assay/autoclave load station 110, in which assays are taken from each column assembly to check the amount of parent and daughter radionuclide produced during elution. Each column assembly is eluted with a suitable volume of saline, and the resulting solution is assayed to check the parent and daughter radionuclide levels in the assay. Where the radioactive material is Mo-99, the elutions are assayed for both Tc-99m and Mo-99. Column assemblies having a daughter radionuclide (e.g., Tc-99m) assay falling outside an acceptable range calculation are rejected. Column assemblies having a parent radionuclide (e.g., Mo-99) breakthrough exceeding a maximum acceptable limit are also rejected. Following the assay process, tip caps are applied to the outlet port and the fill port of the column assembly. Column assemblies may be provided with tip caps already applied to the inlet port. If the column assembly is not provided with a tip cap pre-applied to the inlet port, a tip cap may be applied prior to, subsequent to, or concurrently with tip caps being applied to the outlet port and the fill port. Assayed, tip-capped column assemblies are then loaded into an autoclave sterilizer 124 located in the autoclave station 112 for terminal sterilization. The sealed column assemblies are subjected to an autoclave sterilization process within the autoclave station 112 to produce terminally-sterilized column assemblies. Following the autoclave sterilization cycle, column assemblies are unloaded from the autoclave station 112 into the autoclave unloading station 114. Column assemblies are then transferred to the shielding station 118 for shielding. Some of the column assemblies are transferred to the quality control testing station 116 for quality control. In the example embodiment, the quality control testing station 116 includes a QC testing isolator that is sanitized prior to QC testing, and maintained at a positive pressure and a Grade A clean room environment to minimize possible sources of contamination. Column assemblies are aseptically eluted for in-process QC sampling, and subjected to sterility testing within the isolator of the quality control testing station 116. Tip caps are reapplied to the inlet and outlet needles of the column assemblies before the column assemblies are transferred back to the autoclave unloading station 114. The system 100 includes a suitable transfer mechanism for transferring column assemblies from the autoclave unloading station 114 (which is maintained at a negative pressure differential, Grade B clean room environment) to the isolator of the quality control testing station 116. In some embodiments, column assemblies subjected to quality control testing may be transferred from the quality control testing station 116 back to the autoclave unloading station 114, and can be re-sterilized and re-tested, or re-sterilized and packaged for shipment. In other embodiments, column assemblies are discarded after being subjected to QC testing. In the shielding station 118, column assemblies from the autoclave unloading station 114 are visually inspected for container closure part presence, and then placed within a radiation shielding container (e.g., a lead plug). The radiation shielding container is inserted into an appropriate safe constructed of suitable radiation shielding material (e.g., lead, tungsten or depleted uranium). Shielded column assemblies are then released from the shielding station 118. In the packaging station 120, shielded column assemblies from the shielding station 118 are placed in buckets pre-labeled with appropriate regulatory (e.g., FDA) labels. A label uniquely identifying each generator is also printed and applied to each bucket. A hood is then applied to each bucket. A handle is then applied to each hood. The system 100 may generally include any suitable transport systems and devices to facilitate transferring column assemblies between stations. In some embodiments, for example, each of the stations includes at least one telemanipulator 122 to allow an operator outside the hot cell environment (i.e., within the surrounding room or lab) to manipulate and transfer column assemblies within the hot cell environment. Moreover, in some embodiments, the system 100 includes a conveyance system to automatically transport column assemblies between the stations and/or between substations within one or more of the stations (e.g., between a fill substation and a wash substation within the fill/wash station 108). In the example embodiment, some stations of the system 100 include and/or are enclosed within a shielded nuclear radiation containment chamber, also referred to herein as a “hot cell”. Hot cells generally include an enclosure constructed of nuclear radiation shielding material designed to shield the surrounding environment from nuclear radiation. Suitable shielding materials from which hot cells may be constructed include, for example and without limitation, lead, depleted uranium, and tungsten. In some embodiments, hot cells are constructed of steel-clad lead walls forming a cuboid or rectangular prism. In some embodiments, a hot cell may include a viewing window constructed of a transparent shielding material. Suitable materials from which viewing windows may be constructed include, for example and without limitation, lead glass. In the example embodiment, each of the cask loading station 102, the formulation station 104, the fill/wash station 108, the assay/autoclave loading station 110, the autoclave station 112, the autoclave unloading station 114, and the shielding station 118 include and/or are enclosed within a hot cell. In some embodiments, one or more of the stations are maintained at a certain clean room grade (e.g., Grade B or Grade C). In the example embodiment, pre-autoclave hot cells (i.e., the cask loading station 102, the formulation station 104, the fill/wash station 108, the assay/autoclave loading station 110) are maintained at a Grade C clean room environment, and the autoclave unloading cell or station 114 is maintained at a Grade B clean room environment. The shielding station 118 is maintained at a Grade C clean room environment. The packaging stations 120 are maintained at a Grade D clean room environment. Unless otherwise indicated, references to clean room classifications refer to clean room classifications according to Annex 1 of the European Union Guidelines to Good Manufacturing Practice. Additionally, the pressure within one or more stations of the system 100 may be controlled at a negative or positive pressure differential relative to the surrounding environment and/or relative to adjacent cells or stations. In some embodiments, for example, all hot cells are maintained at a negative pressure relative to the surrounding environment. Moreover, in some embodiments, the isolator of the quality control testing station 116 is maintained at a positive pressure relative to the surrounding environment and/or relative to adjacent stations of the system 100 (e.g., relative to the autoclave unloading station 114). FIG. 2 is a perspective view of an example elution column assembly 200 that may be produced with the system 100. As shown in FIG. 2, the column assembly 200 includes an elution column 202 fluidly connected at a top end 204 to an inlet port 206 and a charge port 208 through an inlet line 210 and a charge line 212, respectively. A vent port 214 that communicates fluidly with an eluant vent 216 via a venting conduit 218 is positioned adjacent to the inlet port 206, and may, in operation, provide a vent to a vial or bottle of eluant connected to the inlet port 206. The column assembly 200 also includes an outlet port 220 that is fluidly connected to a bottom end 222 of the column 202 through an outlet line 224. A filter assembly 226 is incorporated into the outlet line 224. The column 202 defines a column interior that includes a retaining media (e.g., alumina beads, not shown). As described above, during production of the column assembly 200, the column 202 is charged via the charge port 208 with a radioactive material, such as Molybdenum-99, which is retained with the interior of the column 202 by the retaining media. The radioactive material retained by the retaining media is also referred to herein as the “parent radionuclide”. During use of the column assembly 200, an eluant vial (not shown) containing an eluant fluid (e.g., saline) is connected to the inlet port 206 by piercing a septum of the eluant vial with the needle-like inlet port 206. An evacuated elution vial (not shown) is connected to the outlet port 220 by piercing a septum of the elution vial with the needle-like outlet port 220. Eluant fluid from the eluant vial is drawn through the elution line, and elutes the column 202 containing parent radionuclide (e.g., Mo-99). The negative pressure of the evacuated vial draws eluant from the eluant vial and through the flow pathway, including the column, to elute daughter radionuclide (e.g., Tc-99m) for delivery through the outlet port 220 and to the elution vial. The eluant vent 216 allows air to enter the eluant vial through the vent port 214 to prevent a negative pressure within the eluant vial that might otherwise impede the flow of eluant through the flow pathway. After having eluted daughter radionuclide from the column 202, the elution vial is removed from the outlet port 220. The column assembly 200 shown in FIG. 2 is shown in a finally assembled state. In particular, the column assembly 200 includes an inlet cap 228, an outlet cap 230, and a charge port cap 232. The caps 228, 230, 232 protect respective ports 206, 214, 220, and 208, and inhibit contaminants from entering the column assembly 200 via the needles. Prior to final packaging, elution column assemblies of radionuclide generators intended for use in the medical industry are sterilized such that when sterile eluant is eluted through the device, the resulting elution is also sterile and suitable for injection into a patient. Known methods of sterilizing column assemblies include aseptic assembly, and autoclave sterilization of a vented column assembly. Aseptic assembly generally includes sterilizing components of the column assembly separately, and subsequently assembling the column assembly in an aseptic environment. Autoclave sterilization generally includes exposing a vented column assembly, having a column loaded with parent radionuclide, to a saturated steam, or a steam-air mixture environment. Elution column assemblies of radionuclide generators intended for use in the medical industry generally undergo sterility testing to ensure the column assemblies are sterile and suitable for producing sterile, injectable elutions. Suitable methods for sterility testing elution column assemblies include membrane filtration and direct inoculation. Direct inoculation generally involves transferring elution from an eluted vial using a syringe into a test tube containing growth media (also referred to as culture media) , and incubating the test tube to determine if any viable microbial organisms exist. In membrane filtration sterility testing, a column assembly is eluted, and the eluted product liquid is passed through a sterile plastic canister containing a sterilizing filter at the canister outlet. If viable microorganisms exist in the product liquid, they are retained by the sterilizing filter inside the canister. The canister is then filled with suitable growth media (e.g., soybean-casein digest medium (TSB) or fluid thioglycollate medium (FTM)), and incubated at a target temperature for approximately 2 weeks to promote growth of any existing microbial life retained by the canister. FIG. 3 is a perspective view of an example sterility test collection kit 300. The example sterility test collection kit 300 includes an inlet needle 302 fluidly connected to two collection canisters 304 via separate fluid conduits 306, and each collection canister 304 includes a membrane filter 308 at a corresponding canister outlet 310 for retaining microbial life. To collect a sterility test specimen from an eluted vial, the inlet needle 302 is fluidly connected to the vial by piercing a septum of the inverted vial, and draining fluid from the vial into the collection canisters 304. A pump (e.g., a peristaltic pump) may be used to facilitate pumping fluid from the vial into the collection canisters 304. Collecting a sterility test sample by membrane filtration includes eluting a column assembly into a vial, draining or otherwise passing the elution liquid into at least one sterility test canister, and filling the canister with growth media after a target number of vials have been drained. Sterility canisters are then processed via incubation at temperatures appropriate for microbial growth, and observed for growth after approximately 2 weeks. Previous methods of sterility testing radionuclide generators, such as Tc-99m generators, included eluting the generators into vials, and transferring the punctured vials to a different location (e.g., a different lab) to collect and process sterility test liquid from the punctured vials. To collect the sterility test samples, the punctured vials are loaded into an isolator, and the isolator contents, including punctured vials, testing supplies, tools, isolator walls, gloves, etc. are sanitized with highly concentrated (30%-35%) vaporized hydrogen peroxide (VHP). Following VHP sanitization, sterility test samples are collected by draining punctured vials through sterility canisters, which are subsequently filled with growth media, sealed, incubated, and observed for growth after approximately 2 weeks. Prior sterility test samples are usually collected about 24 hours after an elution is collected. Prior sterility testing methods are susceptible to both false negative results, and false positive results. False negative sterility testing results can occur due to the amount of time required to collect and process sterility test samples (during which viable microorganisms are not incubated, and have no nutrient supply). False negative sterility testing results can also occur due to prolonged exposure to high radiation fields within the elution vial, which can destroy viable microorganisms. False positive sterility testing results can occur due to repeated handling of punctured vials in “dirty” environments. Methods for sterility testing radionuclide generators (e.g., Tc-99m generators) during the manufacturing and assembly process of the generator are disclosed herein. For example, methods for obtaining a sterility test sample (e.g., by membrane filtration) from a radionuclide generator during the production process are disclosed herein. These methods provide several advantages over prior sterility test methods, as described in more detail herein. Embodiments of the present disclosure facilitate immediate sterility test sample collection following sterilization and elution of radionuclide generator column assemblies. For example, embodiments of the present disclosure include sterilizing column assemblies in an autoclave, loading individual column assemblies into a tungsten transfer shield (or other suitable radiation shield, such as lead or depleted uranium), transferring the transfer shield (including the column assembly) from a negatively pressurized Grade B hot cell into a pre-sanitized, positively pressurized Grade A sterility testing isolator, removing inlet and outlet tip caps, eluting the column assembly into a sterile elution vial via sterile eluent vial (all with pre-VHP-sanitized exteriors), and immediately draining the eluted vial through at least one sterility test canister to collect the sterility test sample. Moreover, in some embodiments, tip caps are re-applied to the column assembly following sterility test sample collection, and the column assembly is re-sterilized and packaged as saleable product, or re-sterilized and re-sampled. FIG. 4 is a perspective view of an example autoclave unloading station 400 suitable for use with the system 100 of FIG. 1. FIG. 5 is a perspective view of an isolator 500 suitable for use in the quality control testing station 116 of FIG. 1. FIG. 6 is a perspective view of an interior 600 of the isolator 500. FIGS. 4-6 include arrows indicating the general process flow for collecting a sterility test sample from a column assembly. As shown in FIG. 4, the autoclave unloading station 400 includes autoclave unloading rails 402, each positioned on the downstream (i.e., unloading) side of an autoclave sterilizer (not shown in FIG. 4). In the example embodiment, the system 100 includes two autoclave sterilizers 124 (shown in FIG. 1), and the example autoclave unloading station 400 includes two sets of autoclave unloading rails 402. Each set of the autoclave unloading rails 402 receives a cart (not shown) containing up to eight racks 404 (with up to eight column assemblies 200 per rack) from one of the autoclave sterilizers 124. The cart may be removed from the autoclave sterilizers 124, and the racks 404 transferred to an autoclave unloading shuttle 406 using an autoclave unloading mechanism including, for example and without limitation, automated, semi-automated, or manual transfer mechanisms such as telemanipulators (e.g., telemanipulators 122, shown in FIG. 1) and pneumatic cylinders. The autoclave unloading station 400 also includes automated tooling 408 (also referred to as “pick-and-place” tooling) configured to automatically transfer one of the column assemblies 200 from one of the racks 404 positioned on the shuttle 406 to a transfer shield 410. The transfer shield 410 is constructed of suitable radiation shielding material including, for example and without limitation, tungsten, lead, and depleted uranium. The transfer shield 410 is operatively connected to a linear slide mechanism 412 (broadly, a transfer mechanism) configured to transfer the transfer shield 410 into a rotating transfer door 414. In the example embodiment, the linear slide mechanism 412 includes a pair of parallel rails 416 that engage a base 418 of the transfer shield 410. In operation, the transfer shield 410 is pneumatically driven by a pneumatic actuator (not shown in FIG. 4), and slides along the rails 416 into the rotating transfer door 414. The base 418 of the transfer shield 410 and the rails 416 are constructed of materials that provide a low coefficient of friction between the base 418 and the rails 416 to facilitate sliding of the transfer shield 410 on the rails 416. In the example embodiment, the rails 416 are constructed of stainless steel, and the base 418 of the transfer shield 410 is constructed of PEEK (polyetheretherketone). In other embodiments, the rails 416 and the base 418 of the transfer shield 410 are constructed of any suitable materials that enable the system 100 to function as described herein. The rotating transfer door 414 is located between the autoclave unloading station 400 and the quality control testing station 116 (shown in FIG. 1), and is configured to transfer the transfer shield 410 containing one of the column assemblies 200 between the autoclave unloading station 400 and the quality control testing station 116 (specifically, an isolator 500 of the quality control testing station 116, shown in FIG. 5). The transfer door 414 includes a cavity 420 sized and shaped to receive the transfer shield 410 therein. In FIG. 4, the transfer door 414 is shown in a first position in which the cavity 420 is open to or in communication with the autoclave unloading station 400 such that the transfer door 414 can receive the transfer shield 410 in the cavity 420. The transfer door 414 is operatively connected to a motor (not shown) that causes the transfer door 414 to rotate about a vertical axis. In some embodiments, the transfer door 414 is connected to a servo-controlled motor to precisely control rotation of the transfer door 414. The transfer door 414 is rotatable between the first position (shown in FIG. 4) and a second position (not shown) in which the cavity 420 is open to or in communication with the interior 600 of the isolator 500. In operation, the transfer shield 410 is positioned within the cavity 420 of the transfer door 414 via the linear slide mechanism 412, and the transfer door 414 rotates from the first position to the second position such that the transfer shield 410 can be transferred to the isolator 500. The transfer door 414 also includes radiation shielding (not shown in FIG. 4) that maintains a minimum thickness (e.g., 6 inches) of radiation shielding between the autoclave unloading station 400 and the external environment when the transfer door 414 is rotated, regardless of the angle of rotation. In other words, the shielding of the rotating transfer door 414 maintains a minimum shielding thickness along shine paths from the autoclave unloading station 400. Suitable materials from which the radiation shielding may be constructed include, for example and without limitation, lead, tungsten, and depleted uranium. In other embodiments, the autoclave unloading station 400 may include any suitable transfer mechanism(s) that enables transfer of a column assembly 200 from the autoclave unloading station 400 to the isolator 500, including, for example and without limitation, a transfer drawer, a two door air lock system, and a telemanipulator. Although not illustrated in FIG. 4, the components of the autoclave unloading station 400 are enclosed within a hot cell or radiation containment chamber. That is, the components of the autoclave unloading station 400 are enclosed within an enclosure constructed of nuclear radiation shielding material designed to shield the surrounding environment from nuclear radiation. Additionally, in some embodiments, the autoclave unloading station 400 is maintained at a Grade B or higher class clean room environment. That is, the autoclave unloading station 400 has a clean room classification of Grade B or higher. The isolator 500 includes an enclosure 502 defining the interior 600 (shown in FIG. 6), and a viewing window 504 to allow an operator to view the interior 600 of the isolator 500. The isolator 500 also includes a plurality of operator access ports 506 to allow an operator to access the interior 600 of the isolator 500, and perform operations therein. The operator access ports 506 may be sealed with suitable films or barriers (not shown in FIG. 5) to provide a seal between the exterior environment and the interior 600. The interior 600 is substantially sealed from the exterior environment to provide a relatively clean environment within which to collect and process sterility test samples. Additionally, as compared to other stations of the system 100 (e.g., the autoclave unloading station 400), the isolator 500 has relatively little or no radiation shielding. In some embodiments, for example, the enclosure 502 is constructed of metals, plastics, glass, and combinations thereof. In one embodiment, the enclosure 502 is constructed of stainless steel, PEEK, and tempered glass. Referring to FIG. 6, the isolator 500 includes a linear slide mechanism 602 configured to transfer the transfer shield 410 from the transfer door 414 and into the interior 600 of the isolator 500. In the example embodiment, the linear slide mechanism 602 is substantially identical to the linear slide mechanism 412 within the autoclave unloading station 400, and operates in substantially the same manner. The isolator 500 also includes an elution collection apparatus 604 and a sterility test sample collection system 606 configured to collect a sterility test sample from a column assembly 200 within the transfer shield 410. The elution collection apparatus 604 includes an eluant vial 608 and an evacuated elution vial (not shown in FIG. 6). The eluant vial 608 contains an eluant (e.g., a saline solution) which elutes the column assembly when fluidly connected thereto. The eluant vial 608 and the elution vial are held in an inverted position by a vial holder 610 configured to position and manipulate the vials to facilitate production of an elution sample and a sterility test sample. For example, the vial holder 610 is configured to position the eluant vial and the elution vial over the inlet port and the outlet port of the column assembly, respectively. The vial holder 610 can then be lowered such that each vial fluidly connects to a respective inlet or outlet port of the column assembly, thereby producing an elution sample within the elution vial. The vial holder 610 may be automated, semi-automated, or manually manipulated (e.g., through the operator access ports 506 in the isolator 500). The sterility test sample collection system 606 includes an inlet needle 612 fluidly connected to two collection canisters via two, separate fluid conduits (not shown in FIG. 6), and a peristaltic pump 614 configured to pump fluid from the inlet needle through the conduits and into the collection canisters. The collection canisters are enclosed within a shielded container 616 constructed of suitable radiation shielding material, including, for example and without limitation, stainless steel, lead, and tungsten. The inlet needle 612, fluid conduits, and collection canisters may have the same configuration as in the sterility test collection kit 300 shown in FIG. 3. As shown in FIG. 6, the inlet needle 612 is oriented in a vertically upward orientation. In operation, after an elution sample is collected in the elution vial, the vial holder 610 is rotated about a vertical axis to position the elution vial over the inlet needle 612. The vial holder 610 is lowered so that the elution vial septum is pierced by the inlet needle 612, which fluidly connects the elution vial with the sterility test sample collection system 606. The contents of the elution vial are then transported to the collection canisters through the fluid conduits with the assistance of the peristaltic pump 614. In other embodiments, the elution collection apparatus 604 may be omitted, and a column assembly 200 may be eluted directly into the collection canisters of the sterility test sample collection system 606. In some embodiments, for example, the sterility test sample collection system 606 may include a septum, instead of the inlet needle 612, that is pierceable by the needle-like outlet port 220 of the column assembly 200 to connect the column assembly 200 to the collection canisters. In such embodiments, the peristaltic pump 614 may be used to draw or “suck” eluent through the column assembly 200 and directly into the sterility test collection canisters without any intermediate vials. Once one or more sample have been collected in the collection canisters, growth media is added to the collection canisters, and the canisters are incubated to promote the growth of any existing microbial life retained by the canisters. The eluant and elution vials are discarded, and new tip caps are applied to the inlet port and the outlet port of the column assembly. After the sterility test sample is collected, the column assembly is transferred back to the autoclave unloading station 400 via the rotating transfer door 414. Specifically, the linear slide mechanism 602 of the isolator 500 slides the transfer shield 410 into the rotating transfer door 414 (shown in FIG. 4), and the transfer door 414 rotates from the second position (not shown) to the first position (shown in FIG. 4) such that the cavity 420 of the transfer door 414 is open to the autoclave unloading station 400. FIG. 7 is another perspective view of the autoclave unloading station 400, including arrows indicating the general process flow of a column assembly when the column assembly is returned to the autoclave unloading station 400 from the isolator 500. When the transfer door 414 is rotated to the first position (shown in FIG. 7), the transfer shield 410 is pulled or otherwise transferred out of the cavity 420 along rails 416, and the automated tooling 408 transfers the column assembly from the transfer shield 410 to a rack positioned on the autoclave unloading shuttle 406. In some embodiments, the column assembly is loaded into one of the autoclave sterilizers 124 (shown in FIG. 1), re-sterilized, and returned to the radionuclide generator production line. The column assembly may then be transferred back to the isolator 500 for additional sterility testing, or transferred to the shielding station 118 to be packaged for sale. In other embodiments, the column assembly may be discarded following collection of a sterility test sample. Embodiments of the systems and methods described herein facilitate collection of a sterility test sample in a relatively clean environment, and within a relatively short amount of time following production of a sterilized column assembly. In some embodiments, for example, a sterility test sample is collected from a column assembly within 4 hours of sterilization, within 2 hours of sterilization, or even within 1 hour of sterilization. Additionally, in some embodiments, a sterility test sample is collected from a column assembly within 7 hours of the column assembly being charged with a parent radionuclide, within 5 hours of the column assembly being charged, or even within 4 hours of the column assembly being charged. An example method of collecting a sterility test sample from a column assembly includes sterilizing a column assembly with a sterilizer (e.g., one of the sterilizers 124), the column assembly including a column having a parent radionuclide contained therein, transferring the column assembly from the sterilizer to a first clean room environment (e.g., the autoclave unloading station 400), transferring the column assembly from the first clean room environment to a second clean room environment (e.g., the isolator 500), and collecting a sterility test sample from the column assembly within the second clean room environment. In some embodiments, the first clean room environment is negatively pressurized, and the second clean room is positively pressurized. Further, in some embodiments, the first clean room environment has at least a Grade B clean room classification, and the second clean room environment has a Grade A clean room classification. Additionally, in some embodiments, such as the embodiment shown in FIGS. 4-7, a column assembly is transferred directly from the sterilizer to the first clean room environment, and directly from the first clean room environment to the second clean room environment to collect the sterility test sample. Another example method of collecting a sterility test sample from a column assembly includes transferring a column assembly from a radionuclide generator production line to an isolator, collecting a sterility test sample from the column assembly within the isolator, and returning the column assembly to the radionuclide generator production line. An example system suitable for carrying out methods of this disclosure includes a sterilization station (e.g., sterilization station 112) including at least one autoclave sterilizer (e.g., autoclave sterilizer 124), a hot cell or radiation containment chamber (e.g., autoclave unloading station 400) adjoining the sterilization station and enclosing a first clean room environment, and an isolator (e.g., QC sampling isolator 500) connected to the hot cell and enclosing a second clean room environment. In some embodiments, the first clean room environment has a clean room classification of Grade B or higher, and includes an autoclave unloader configured to remove the column assembly from the autoclave sterilizer. Additionally, in some embodiments, the isolator has a clean room classification of Grade A, and includes a sterility test sample collection system for collecting a sterility test sample from a radionuclide generator column assembly. Moreover, in some embodiments, the hot cell is negatively pressurized, and the isolator is positively pressurized. The systems and methods of the present disclosure provide several advantages over known sterility testing procedures and systems. For example, embodiments of the disclosed systems and methods facilitate minimizing false negative sterility test results by reducing the time between column assembly production and sterility testing. Embodiments of the present disclosure include eluting radioactive liquid from column assemblies into vials, immediately draining the contents of the eluted vials into sterility testing canisters, adding growth media to the canisters, and incubating the canisters within a relatively short time after elution. Minimizing the time between elution collection and sterility testing facilitates detection of viable microorganisms present in the column assembly. Other methods wait up to 24 hours post-elution before starting the sterility testing process. During that time, living microorganisms present in the column assembly elution may die from lack of nutrients, or die from high background radiation present in the elution, resulting in a false negative sterility test result. Embodiments of the disclosed systems and methods also facilitate minimizing false positive sterility test results by reducing the amount of handling and exposure to relatively dirty environments as compared to prior sterility test methods. For example, because elutions are collected and immediately drained within a sanitized Grade A environment, methods and systems of the disclosure facilitate minimizing the possibility of a false positive sterility test result caused by external contamination from repeated handling of punctured vials in dirty environments. Additionally, the systems and methods of the present disclosure facilitate reuse of column assemblies that are used for quality control (i.e., sterility testing). For example, because new tip caps are applied to column assembly inlet and outlet ports within a Grade A clean room environment after sterility test samples are collected, the column assemblies can be re-sterilized and sold, or re-sampled in the isolator. Additionally, embodiments of the systems and methods described herein provide an asynchronous pipeline that facilitates continued production of saleable generators even if sterility testing equipment is temporarily inoperable. For example, if sterility testing equipment or transfer equipment temporarily prevents the transfer of column assemblies from the autoclave unloading station to the sterility testing isolator, column assemblies targeted for quality control sterility sampling can be held in a buffer area (e.g., between the autoclave unloading rails shown in FIG. 4, or on a semicircular buffer near the left-most pick and place station shown in FIG. 4), while other column assemblies not targeted for QC sampling are transported to final packaging. Because the sampling pipeline is asynchronous, the system and methods facilitate minimizing delays that might otherwise impact process throughput. When introducing elements of the present invention or the embodiment(s) thereof, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements. As various changes could be made in the above constructions and methods without departing from the scope of the invention, it is intended that all matter contained in the above description and shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.
047755083	claims	1. A corrosion and crack resistant water reactor fuel cladding tube comprising: an outer cylindrical layer of a first zirconium alloy selected from the group consisting of Zircaloy-2 and Zircaloy-4; an inner cylindrical layer of a second zirconium alloy consisting essentially of: about 0.05 to 0.2 wt.% iron, about 0.05 to 0.4 wt.% niobium, about 0.03 to 0.1 wt.% of an element less than 2000 ppm total impurities; 30- 700ppm oxygen; and zirconium forming essentially the balance; said inner cylindrical layer metallurgically bonded to said outer layer; and whereby said inner cylindrical layer has an aqueous corrosion resistance which is at least substantially equivalent to the corrosion resistance of said outer cylindrical layer. 2. The water reactor fuel cladding tube according to claim 1 wherein said second zirconium alloy has nickel content of 0.03-0.1 wt.% and a chromium content of less than 200 ppm. 3. The water reactor fuel cladding tube according to claim 1 wherein said second zirconium alloy has a chromium content of 0.03 to -0.1 wt.%, and a nickel content of less than 70 ppm. 4. The water reactor fuel cladding tube according to claim 1 wherein said second zironium alloy has a niobium content of 0.05 to 0.2 wt.%. 5. The water reactor fuel cladding tube according to claim 1 having a weight gain of less than 200 mg/dm.sup.2 and an essentially black, adherent oxide film on said inner and said outer layers after 24 hours exposure to a 500.degree. C. 1500 psi steam test. 6. The water reactor fuel cladding tube according to claim 1 wherein said inner cylindrical layer has a fully recrystallized microstructure.
	description	The present invention is directed to monitoring of a nuclear reactor pressure vessel. More particularly, the present invention is directed to a system and method for wirelessly monitoring a condition of a nuclear reactor pressure vessel. The mechanical movement (i.e. insertion, withdrawal) and the associated monitoring of the position of the control rods are necessary functions for the operation of a nuclear reactor. Each of the instruments that perform this function typically is terminated with a power cable and one or two position indication cables that transmit signals from the instrument back to processing units, typically located in a control room. As used herein, the term instrument may also include a sensor or sensing device. Known rod position indicator cable systems, such as the one depicted in FIGS. 1 and 2, typically include multi pin connector disconnect points 10 located at the top of the nuclear reactor vessel head 12 and at the reactor cavity wall 14 poolside. Additional disconnect points 10 may also be located at other points between the vessel head 12 and the cavity wall 14. The multi pin connector disconnect points 10 allow each of the interconnecting cable sections 16 to be removed from corresponding sensing instruments 18 to allow for the disassembly of the reactor vessel 8 for refueling. The typical reactor vessel 8 includes on the order of magnitude of 100 or more of these cable assemblies. The removal and installation of the cable sections 16 is generally part of the “critical path” schedule for a refueling outage and generally requires the services of a specially trained crew of technicians during both the initial and concluding stages of the refueling outage in order to complete the work. Typically, such work can take up to an entire shift to complete. In total, the manipulation of the signal cable sections 16 may occupy an entire day of a 30 day outage. Given an estimated cost of $20,000 to $25,000 per hour of lost critical path time, this one day period would represent a cost of approximately $500,000 per refueling outage without even taking into consideration the cost of the trained work crew. Additionally, the repeated manipulation of the signal cables increases the potential for damage, leading to the need to repair and/or replace the cables and/or the related hardware. Furthermore, the manipulation of the signal cables must be carried out in a radiation area located above the reactor vessel. Elimination of this work scope would thus eliminate the radiation exposure associated with this work activity. Accordingly, there exists room for improvement in the system and method for monitoring the position of the control rods and other reactor conditions. In accordance with an embodiment of the invention, a method of monitoring a condition of a nuclear reactor pressure vessel disposed in a radioactive environment is provided. The method comprises: sensing a condition of the reactor pressure vessel with an instrument, transmitting a signal indicative of the condition of the reactor pressure vessel from the instrument to a powered wireless transmitting modem disposed in the radioactive environment, wirelessly transmitting a signal indicative of the condition of the reactor pressure vessel from the transmitting modem to a receiving modem in the line of sight of the transmitting modem, transmitting a signal indicative of the condition of the reactor pressure vessel from the receiving modem to a signal processing unit, and determining the condition of the reactor pressure vessel from the wirelessly transmitted signal. The wireless transmission may comprise an infrared transmission. The condition of the reactor pressure vessel may be sensed by a plurality of instruments operatively connected with a plurality of transmitting modems. The plurality of wireless transmitting modems may transmit signals to a plurality of receiving modems operatively connected with the signal processing unit for determining the condition of the reactor pressure vessel. The condition of the reactor pressure vessel may be sensed by a plurality of instruments operatively connected with a transmitting modem and the transmitting modem may transmit a signal to a receiving modem operatively connected with the signal processing unit for determining the condition of the reactor pressure vessel. The condition of the reactor pressure vessel may be determined during power generation operations. The condition of the reactor pressure vessel may be determined while the reactor pressure vessel is disassembled. The powered transmitting modem may be bridged with a second powered transmitting modem so that the second transmitting modem will continue to function should its power source fail. The transmitting modem may be powered by a regenerative battery. The transmitting modem may be externally powered. The transmitting modem may be powered parasitically from a power cable associated with a control rod drive mechanism. The condition monitored may be one of: control rod position, coolant water bulk temperature, coolant water level, radiation level, and ion chamber level. In accordance with another embodiment of the invention, a system for monitoring a condition of a nuclear reactor pressure vessel disposed in a radioactive environment is provided which comprises an instrument structured to monitor a condition of the nuclear reactor pressure vessel, a powered wireless transmitting modem disposed in the radioactive environment, a receiving modem in the line of sight of the transmitting modem, and a signal processing unit electrically coupled to the receiving modem. The wireless transmitting modem is electrically coupled to the instrument. The receiving modem is in wireless communication with the transmitting modem. The signal processing unit is structured to determine the condition of the nuclear reactor pressure vessel from the instrument. The condition of the reactor pressure vessel may be sensed by a plurality of instruments operatively connected with a plurality of transmitting modems. The plurality of wireless transmitting modems may transmit signals to a plurality of receiving modems operatively connected with the signal processing unit for determining the condition of the reactor pressure vessel. The condition of the reactor pressure vessel may be monitored during power generation operations. The condition of the reactor pressure vessel may be monitored while the reactor pressure vessel is disassembled. The powered transmitting modem may be bridged with a second powered transmitting modem so that the second transmitting modem will continue to function should the powered transmitting modem fail. The powered transmitting modem may be powered by a regenerative battery. The powered transmitting modem may be externally powered. The powered transmitting modem may be powered parasitically from a power cable associated with a control rod drive mechanism. The condition monitored may be one of control rod position, coolant water bulk temperature, coolant water level, radiation level, and ion chamber level. The instrument may comprise a plurality of sensing instruments, each instrument being structured to monitor a condition of the nuclear reactor pressure vessel. The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which examples of the invention are shown. The invention may, however, be embodied in many different forms and should not be construed as limited to the examples set forth herein. Rather, these examples are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout. FIGS. 3 and 4 illustrate an example improved monitoring system 20 in accordance with the present invention that provides for the monitoring of one or more conditions of a nuclear reactor pressure vessel 8 without the need of cable sections 16 (such as those shown in FIGS. 1 and 2). As shown in FIG. 4, the multi pin connectors 10 (shown in FIGS. 1 and 2) at both ends of the former cable section 16 are replaced with wireless modems 22,26, with each modem 22,26 having a respective integral mating connector assembly 24,28. The modem 22 at the instrument 18 end (i.e. at the reactor vessel 8, FIG. 4) is a wireless transmitter electrically coupled to the instrument 18, while the modem 26 at the reactor cavity wall 14 (FIG. 3) is a wireless receiver. The term “modem”, as used herein, shall be used to refer to a suitable electrical device capable of at least one of sending and receiving wireless transmission signals such as, for example, without limitation, via infrared transmission. The remainder of the rod control position and other instrument signal hardware is not changed from that shown in FIGS. 1 and 2. Referring to FIG. 4, the transmitter modem 22 is parasitically powered from the power cable 17 for the associated rod control drive mechanisms. This is accomplished by insertion of a double-ended multi pin connector assembly 30 in series with the existing power cable 17 at the multi pin connector on the instrument assembly 18. This double-ended multi pin connector assembly 30 also includes an appropriately sized parasitic bleed power cable 32 that is mated to, and powers, the neighboring transmitter modem 22 and instrument 18. Each modem typically only requires a fraction of a watt to power which has a generally transparent effect on the capacity of the comparably massive power cable 17. Likewise, the voltage potential required to operate the level indication probe (not numbered) could be reduced, if needed, whereas an overly amplified signal is not required or desired at the front end of the modem 22. Therefore, sufficient source power is available without significant additional modification to an existing power cable circuit. Additionally, expected power supply interruptions from the power cables as a result of instrument operations (i.e. mechanical control rod movement and static retention mode) may be bridged and conditioned within either the modem 22 and/or the double ended connector assembly 30 in the power cable circuit. Although not a preferred embodiment, it can also be appreciated that the power for each of the modems 22 could be supplied from alternate power sources found within the reactor vessel assembly (e.g., without limitation, power sources for thermocouples, solenoid operated devices, fan motors, switches, lighting) and/or dedicated power sources (e.g., without limitation, regenerative batteries). In another example, one or more of the transmitting modems 22 may be bridged with a second transmitting modem (not shown) powered by a different power source. Such redundant arrangement would provide for the second transmitting modem to continue to function should the power source of the transmitting modem 22 fail. In yet another example, one or more of the transmitting modems 22 may be electrically coupled to a plurality of instruments 18 for detecting and transmitting one or more conditions of the reactor. Such arrangement may be employed to reduce the number of modems 22 needed. Such an arrangement may also be employed to provide redundancy by electrically coupling one instrument to multiple modems 22 (and thus having each modem electrically coupled to multiple instruments 18). The receiver modem 26 is installed on the “abandoned” end (i.e. electrical connector 10) of the existing rod position indication cables located at the reactor cavity wall 14 (FIG. 3). Preferably each of the receiver modems 26 is installed within the line of sight of each of the corresponding transmitting modems 22. Such line of sight transmission generally minimizes power requirements and the possibility of interference with the transmitted signals. Each of the receiver modems 26 may be supplied power either from the existing source voltage of the existing rod position indication cable system, parasitically from the associated power cable system, or from an alternate or dedicated power source(s). In a preferred embodiment, each existing signal cable end is assigned a discrete modem 26. That is, if there were fifty signal cables, there would be fifty transmitter modems 22 and fifty receiver modems 26. It is to be appreciated that the modems 22,26 could be combined into a lesser number of larger modems. It is also to be appreciated that the present invention may be incorporated into other in-containment cable instrumentation systems that would benefit from elimination of interconnecting cable assemblies (e.g., without limitation, reactor vessel level indication, containment area radiation monitors and ion chambers). In installations with two or more independent level indication instruments for a particular mechanism, one instrument could be outfitted according to the present invention while the second or others could remain unchanged. Such arrangement would provide additional system redundancy using independent hardware. 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 arrangements disclosed are meant to be illustrative only and not limiting as to the scope of invention which is to be given the full breadth of the claims appended and any and all equivalents thereof.
	summary
056195460	abstract	A fluid tight mechanical clamp for creating a compressed graphite seal between a resistance temperature detector nozzle and a NSSS piping hot or cold leg pipe is provided which includes a split graphite seal ring, a peripheral seal back-up ring, a split load sleeve to axially compress and radially expand the split seal ring, a reactor plate and load ring with bolts to drive the load sleeve and compress the seal, and a blowout retainer to prevent the nozzle from blowing out of its seat in the pipe wall in the event of a weld failure. Extensive welding procedures to repair nozzle leaks are thus eliminated.
	abstract	Provided is a method of the simulation construction for measurement of the control rod insertion time including a three-dimensional modeling operation of an inside wall of the nuclear reactor, a control rod, etc; a flow field configuration operation wherein the flow field is differentially configured by a variable grid system comprising variable cells which change the configuration and by an aligned grid system comprising fixed cells which maintains the configuration; a calculation operation of simulation estimated value for the insertion time by analyzing the thermal-hydraulic phenomenon using the three-dimensional CFD; and a cell change operation, wherein an error between the estimated value and the actual value is verified whether the error lies within the reference range, and, when the error exceeds the reference range, the size of the variable cell and/or of the size of the fixed cell is changed.
048633119	description	DETAILED DESCRIPTION A borehole 16 is provided in a salt formation 13. The borehole 16 is tightly lined or covered by superimposed and welded together tubular sections 1 as well as with a correspondingly constructed bottom portion 15 on the bottom of the boreholes, which likewise is welded to the lowermost tubular section 1. Each tubular section 1 consists of steel and is composed of three rings, an outer ring 2, an inner ring 3 and an intermediate ring 4. All three rings, 2, 3, and 4 are securely fixed to each other. The intermediate ring 4 consists of an electrochemically nobler material, than the material (e.g. spherical cast graphite) of the outer ring 2 and the inner ring 3. In the assembly of the total covering of the borehole 16 the tubular section 1 is joined by welding of the intermediate rings 4 with each other via the welding seam 11. In order that the welding can be carried out on the inside, the inner ring for forming a recess 5 has a lower height than the outer and intermediate rings 2 and 4. The recess 5 can have either a rectangular or trapezoidal cross-section. Optionally the recess 5 can contain a surface adapted to the welding apparatus and testing apparatus for guaranteeing the quality of the welding seam 11 respectively a correspondingly shaped recess 14. The outer rings 2 have on the upper and lower edges directly on the intermediate ring 4 in each case a recess 6. In each of the recesses 6 there is applied a support ring 7 having double the height of the depth of the recess of the recess 6. The support ring 7 consists of the same material as the intermediate ring 4 and is welded to the intermediate ring 4. In the assembly of the total covering of the borehole 16 there is applied in each case a support ring 7 in the free recess of the adjacent outer ring. The bottom 8 of the recess 6 in the outer ring 2 thereby sits deeper in the inner ring 3 than the bottom 9 of the recess 5. Altogether there are the following advantages: In producing the welding seam 11 the weld melt is surrounded on all sides by the same material. As a result of this there is guaranteed a homogeneous structure in the welding seam and in the surrounding area and this guarantees a qualitatively trouble-free weld joint. The support ring 7 takes on a static function in regard to the pressure of the rock against the recess 5 and at the same time relieves the welding seam 11. During longterm storage or terminal storage of the terminal storage container or terminal storage package 12 the less noble outer ring 2 can be corroded or in the extreme case completely corroded away. The support ring 7 consisting of a nobler material in such a case supports the hold covered against the geological formation, in cooperation with the intermediate ring 4 protects before there is further corrosion and thus takes on a barrier function for the terminal storage container 12. The total thickness of the tubular section 1 can be chosen so that additionally for the terminal storage container 12 also there can be assumed completely or to a high degree the shielding function against the radioactive rays of the radioactive container material. The same is also true for the static function against the rock pressure so that the terminal storage container 12 can be reduced in size not only in regard to protection against rays but also in regard to stability. The chief static function of the tubular section 1 thereby is assumed by the correspondingly laid out inner ring 3. The covering of the invention thus is preeminently suited to take care of essential container functions so that the numerous terminal storage containers can be laid out tightly, but simply, at low-cost, easily and handled comfortably. As an aid in the assembly of the tubular sections 1, as well as the bottom portion 15 in a bore hole, on one of the recesses 6 of each outer ring 2, there can be inserted a support ring 7 to facilitate interengagement between each layer of rings. In addition, the inner ring 3 may be provided with a recess 10 for cooperation with a manipulating device to facilitate movement of the rings. The entire disclosure of German priority application No. P 3445124.2 is hereby incorporated by reference.

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