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047568739	summary	BACKGROUND OF THE INVENTION 1. Field of the Invention The invention relates to a single loop nuclear power plant for electrical power generation, and more paprticularly to a plant with helium cooled high temperature reactor utilizing spherical fuel elements. The plant has a gas turbine aggregate made up of a gas turbine and a two-stage compressor, with a heat exchanger apparatus exhibiting radiators, intermediate radiators and a recuperator, together with gas carrying lines between components of the loop. 2. Description of the Related Technology The installation described in DE Nos. 22 41 426 and 24 04 843 have a gas turbine aggregate located in a horizontal tunnel below the high temperature reactor installed in the center cavity of a prestressed pressure vessel. The heat exchange apparatuses are located in vertical shafts, arranged on a partial circle around the center cavity. The known single loop nuclear power plants are desired for higher capacities and require much space in spite of their compact layout. SUMMARY OF THE INVENTION An object of the invention is to develop a plant suitable for an output of 1 to 5 MWe and requiring a small amount of space. The object may be attained by a single loop nuclear power plant for electric current generation with a helium cooled high temperature reactor charged with spherical fuel elements. A gas turbine aggregate or assembly of a gas turbine and a two-stage compressor with heat exchange apparatus is utilized. The heat exchange apparatus comprise radiators, intermediate radiators and a recuperator, together with gas carrying lines between the circulation components. The plant is housed in two releasably connected pressure vessels placed above each other. The pressure vessels are separated in a gas tight manner. The lower pressure vessel contains the high temperature reactor and is charged with the primary gas. The upper pressure vessel is filled with a protective gas and contains the circulation components. The gas turbine, radiators, low pressure compressor, intermediate radiators, high pressure compressor, and the generator are arranged above each other in sequence and aligned with the high temperature reactor. The recuperator may be located laterally from the other circulation components and connected to the gas turbine and the radiators by approximately horizontal gas lines. The installation is arranged for upward helium flow through the high temperature reactor. Thereafter the helium is conducted through a gas conduit directly to the inlet of the gas turbine. The two pressure vessels are preferably cylindrical and made of steel. The spherical fuel elements forming the reactor core remain in the high temperature reactor until their final burnup. If power production requirements are for a limited time period, use of a plant according to the invention is favorable. The installation may be laid out against external effects, such as for example earthquakes due to its compact configuration. The generator may be installed in the upper pressure vessel or in its own container set upon the upper pressure vessel. The gas turbine aggregate may be bearingly supported in either dry or magnetic bearings. Single loop nuclear power plant according to claims 2 or 3, characterized in that the generator may advantageously be a high speed generator without topping gear and equipped with magnetic bearings. The protective gas for the upper pressure vessel may be helium or nitrogen. Any decay heat may be removed by natural convection through the radiators. Advantageous further developments of the invention will become apparent from the description below of an embodiment with reference to the schematic drawing.
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044029047	description	DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 illustrates the upper portion of a nuclear fuel assembly 10 including a square array of Zircaloy clad fuel rods 12 carried and supported by a series of axially spaced, square grids 14 which are fixedly connected to a plurality of guide tubes 16. The upper end fitting 18 includes a locking post 20 which is screwed into a boss 22 on the guide tube 16, and a coil spring system 24 for holding the assembly in place during reactor operation. During a typical reactor refueling, each assembly is at some point removed from the core and supported under water where inspection of the fuel rods can be made. It should be appreciated that the fuel rods 12 located deep within the 14.times.14 array cannot be easily inspected. If, for example, it is suspected that at least one rod 12 within the array is leaking, it may be necessary to disassemble the assembly to isolate and verify the failed rod. In the illustrated assembly 10, the posts 20 may be unscrewed and, together with the spring system 24, lifted off the assembly to expose the end caps 26 of the fuel rods. The suspect rods may then be lifted out of the assembly and inspected for failure. According to the present invention as shown in FIG. 2, a simpler method of quickly and easily identifying failed fuel rods avoids the inconveniences and delays associated with conventional fuel inspection techniques. A single fuel rod 12 is shown in partial section to reveal a fuel pellet 28, a disc 30, and a "C" type resilient member 32 for maintaining a downward bias on the pellet column. A plenum region 34 is provided within the upper end of the Zircaloy tube or clad 36, which is sealed with a welded Zircaloy end cap 26. Connected to a cavity 38 within the end cap 26 and extending into the plenum 34 is a wad or compact 40 of the zirconium wool. The change in the electrical conductivity of the wad 40 resulting from excessive moisture due to fuel rod failure, forms the basis of the present invention. The change in conductivity can be readily determined by conventional eddy current equipment as represented by the probe 42. Referring also to FIG. 1, in the preferred mode for carrying out the invention, each new fuel rod 12 fabricated for inclusion in a fresh assembly 10 is sealed with an end cap 26 which has mounted therein a wad or compact 40 of a porous or fibrous, electrically conducting metallic material of a type that undergoes a permanent change in electrical conductivity when exposed to water. Since fuel failure would generally occur, if at all, while the fuel rod 12 is generating power in a nuclear reactor core, the wad transformation mechanism begins with coolant water or water vapor entering the rod 12 somewhere along its active length and immediately being superheated in the gap 44 by contact with the fuel pellet surface 28, which is typically at about 1500.degree. F. (816.degree. C.). The water vapor rises through the gap 44, which is typically at least 1000.degree. F. (538.degree. C.), to the plenum region 34 where it contacts and oxidizes the wad 40, which is typically at a temperature of at least 750.degree. F. (399.degree. C.). Thus, the conductivity of the wad 40 should be permanently altered at these conditions, even if no significant transformation would occur at ambient conditions. Zirconium, zirconium ferrite, and other zirconium based materials are suitable, and other metals may be suitable to varying degrees. After the requisite number of fuel rods 12 have been fabricated, they are bound together to form a fresh fuel assembly 10. Either before or after the fuel rods are bound into an assembly, but before the assembly is loaded into the reactor core, an eddy current probe 42 is placed around the end cap 26 of at least one of the fuel rods and an external scan is made. The output signal characteristic of a dry (less than about 10 ppm H.sub.2 O), newly fabricated fuel rod is thus established. With a zirconium wool compact 40, the difference in probe signals between a dry rod and a failed rod is so dramatic that only one base reading for a dry rod need be made. The probe output signals for all other dry rods will be quite similar. The assembly 10 is then placed in a nuclear reactor core where it will generate fission power through at least one burnup cycle. Between cycles the core is refueled and the assemblies may be inspected. Usually, the assemblies are individually inspected in a pool outside the reactor vessel. With the present invention, the eddy current probe 42 is placed over every end cap 26 of the assembly to determine whether any rod has failed. Rod failure is evidenced by the significantly different probe output signals obtained when the zirconium wool has become electrically nonconducting zirconium oxide. The wad may even become powdery and disappear from the plenum as it falls down along the pellet column. In FIG. 1 it may be seen that with the typical fuel assembly illustrated, a space is provided between the end caps 26 and the parts of the upper end fitting 24 that obstruct direct access to the end caps from above the assembly. In this assembly all fuel rods 12 in the square array may be inspected by a suitably angled probe 42. Preferably, many rods 12 are inspected simultaneously using a plurality of probes 42. If some rods 12 are not accessible, the upper end fitting 18 may be removed to expose the end caps 26, by unscrewing the locking post 20 and lifting the spring system 24. Despite this inconvenience, however, the present permits inspection of all fuel rods 12 in the array without the need to pull any rods out of the assemblies 10. With conventional techniques which rely on inspection of the entire rod surface, even the removal of the spring system 24 would not expose the interior rods for inspection along their entire lengths. When, as in the preferred embodiment, a single dry rod inspection is relied upon to establish a characteristic signal for a multiplicity of rods in many assemblies 10, all rods 12 should, of course, contain wads 40 that have approximately the same general shape and mass. It should be appreciated that the invention is not limited to the foregoing embodiment. For example, the wad 40 may be located elsewhere in the rod 12, such as the bottom, if this location is more acessible for post-irradiation inspection. The tube could be made of stainless steel or other conducting metal. Also, the invention can be adapted for inspecting fuel rods or other sealed tubes during manufacturing to determine whether the rods have unacceptably high water or water vapor content. The choice of wad material and surface-to-volume ratio for the wad should depend on the conditions under which water at a relatively higher pressure would leak into a defective rod.
	abstract	The invention relates to a container (100, 901, 902, 903, 904, 905, 906, 907, 908, 909, 910) for the production of radioisotopes by irradiation of a precursor material formed by a one-piece metal casing, the wall of said casing including one thin portion (130) having a thickness of between 5 and 100 μm, the remainder having a thickness greater than 100 μm. The invention also relates to a method for obtaining the container and to a target assembly using same.
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	abstract	Disclosed herein is a method comprising heating helium in a core of a nuclear reactor; extracting heat from the helium; superheating water to steam using the heat extracted from the helium, expanding the helium in a turbine; wherein the turbine is in operative communication with an electrical generator; and generating electricity in the electrical generator.
	description	1. Field of the Invention Example embodiments relates to a grapple and a process for inserting, rearranging and/or removing control rods blades, fuel support castings and control rod guide tubes from fuel assemblies of a Boiling Water Reactor (BWR) nuclear core. The grapple may lift all three objects as a single unit during refueling operations and/or plant maintenance. 2. Related Art The control rods in a boiling water reactor contain an absorbent material that when positioned in the reactor core can be used to slow the fission rate of the nuclear fuel. However, the absorbent material is subject to degradation after extended use. Therefore, it is periodically necessary to replace the control rods. Since different regions of the reactor core have different levels of irradiation fluence, in order to reduce expenses, it is common to periodically reposition the control rods within the core to maximize their useful life. Conventionally, grapples have been used to grip the control rod blade and/or fuel support casting from the core. These grapples may remove the control rod blade and fuel support casting either individually, or in unison with each other. A separate grapple has conventionally been used to remove the control rod guide tube, adding time to the critical path during a refueling and maintenance outage. Example embodiments provide a method and an apparatus for rearranging and/or replacing control rods in a boiling water reactor (BWR). Example embodiments provide a method and a grapple that may simultaneously remove the control blade, fuel support casting and control rod guide tube from the reactor, all in one movement. The grapple may include a frame, control rod blade (CRB) hooks capable of gripping the bail handle of a control rod, opposing fuel support casting (FSC) hooks capable of grasping the fuel support casting, and opposing control rod guide tube (CRGT) hooks that may be pneumatically actuated to slide into control rod guide tube orifice holes to remove the guide tube in unison with the control rod and the fuel support casting. Detailed example embodiments are disclosed herein. However, specific structural and functional details disclosed herein are merely representative for purposes of describing example embodiments. Example embodiments may, however, be embodied in many alternate forms and should not be construed as limited to only the embodiments set forth herein. Accordingly, while example embodiments are capable of various modifications and alternative forms, embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that there is no intent to limit example embodiments to the particular forms disclosed, but to the contrary, example embodiments are to cover all modifications, equivalents, and alternatives falling within the scope of example embodiments. Like numbers refer to like elements throughout the description of the figures. 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” or “coupled” to another element, it may 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 context clearly 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. FIGS. 1-3 are perspective and side views of a conventional grapple 40. Grapple 40 may be used to lift, remove and replace a fuel supporting castings (FSC) 406 (FIG. 14) and control rod blades (CRB) 402 (FIG. 12) used within the reactor pressure vessel in boiling water reactors. Grapple 40 includes a frame 42, a control rod blade (CRB) hooking mechanism 55 having a sliding bar 51, and a pair of spaced apart fuel support casting (FSC) hook mechanisms 70. The CRB hooking mechanism 55 is designed to engage a top bail handle 22 of a control blade 20. The FSC hooking mechanisms includes two FSC hooks 80 facing opposing directions. The FSC hooks are designed to grab a FSC 406. Frame 42 includes a top plate 43, a bottom plate 44, a center plate 45 (FIG. 2), a support rim 46 positioned between the top 43 and center plates 45, and a plurality of five frame posts 47. The frame posts 47 extend between the bottom plate 44 and the top plate 43. Frame 42 may be an open structure with large central openings being provided between plates 43/44/45 for maintenance and use of grapple 40. In operation, the upper end of sliding bar 51 is coupled to a hoist cable (not shown) by a threaded connector. The hoist cable can be moved back and forth by an operator working from a refueling platform (not shown) to position grapple 40 during operation. A header plate 52 is mounted on the bottom (distal) end of the sliding bar 51. The CRB hook 55 is pivotally coupled to cage 57 and extends downward from header plate 52. A first end of an air cylinder 62 is attached to sliding bar 51 by bracket 63. The second end of the air cylinder 62 is coupled to the CRB hook 55 such that actuation of the air cylinder in a first direction will cause the hook 55 to pivot forward towards a front of the grapple frame 42. When grapple 40 is properly positioned, this action will cause the CRB hook 55 to move from a withdrawn position to an extended position (as shown in FIGS. 16A-16B), when the CRB hook 55 is positioned under the top bail handle 22 of a control rod blade 20. When the air cylinder 62 is withdrawn, the CRB hook 55 will be withdrawn as well. A pair of guides 65 are attached to opposing sides of the header plate 52 to assist with positioning the grapple 40 when grapple 40 is lowered into place. Guides 65 have tapered bottom surfaces that help ensure that grapple 40 will properly center over a control rod bail handle 22 when grapple 40 is lowered into place. Guides also limit flopping of a control rod blade 20 when the control rod blade 20 is being inserted or withdrawn from a reactor core. The sliding bar 51 carries the entire CRB hooking mechanism 55. When the grapple 40 is lowered into place over a control rod 400 (FIG. 15), the frame 42 will move together with the hoist cable until the bottom plate 44 of frame 42 comes into contact with the fuel support casting (FIG. 14). Thereafter, slider bar 51 will continue downward with the hoist cable until cage 57 seats on control rod bail handle 22. Thus grapple 40 is adapted to work with different sized control rods. Indeed, slider bar 51 is relatively long in order to accommodate any length BWR control rod. Slider bar 51 also provides the ability to lift the control rod 400 prior to lifting the fuel support casting 406 (FIG. 14), to verify that the control rod 400 has been unlatched from the control rod drive. The FSC hooking mechanisms 70 are mirror images of one another, and will be described in more detail herein. Each FSC hooking mechanism 70 includes a fixed guide 72, a plunger 74, and a pivot bar 77. The FSC hooking mechanisms 70 are slidably coupled to frame 42 by a slot and pin arrangement (best shown in FIG. 3). Each guide 72 includes two pairs of opposing vertically spaced pins 121 (FIG. 3) which fit into a pair of vertically extending opposing slots 123 (also shown in FIG. 3) formed in retaining plates 125 that extend downward from center plate 45. Thus, the FSC hooking mechanisms 70 can travel a small distance vertically, relative to the frame, in an amount that is dictated by the arrangement of the pins 121 and slots 123. Pivot bar 77 is pivotally coupled to guide 72 by a pivot 79. A FSC hook 80 is on the distal end of FSC hooking mechanism 70 and faces outward. The back surface of pivot bar 77 is positioned above pivot 79 and is inclined inward relative to the back surface of the portion of the pivot bar 77 that is located below the pivot 79. The FSC hooking mechanisms 70 are mounted to frame 42 in a manner such that guides 72 extend well below the bottom plate 44 of frame 42. Thus, when grapple 40 is positioned over a fuel support casting 406, guides 72 will extend into diagonally opposite side flow orifices 406a of the casting 406 (see FIG. 14). A pair of mechanical switches 86 (see FIG. 3) are positioned on a top surface of bottom plate 44 to prevent air cylinders 82 from releasing while a fuel support casting 406 (FIG. 14) is being held. The fuel support casting 406 is supported by plungers 74 and the FSC hooks 80 rather than bottom plate 44 of frame 42. Since the FSC hooking mechanisms 70 are slidable a small distance relative to the frame 42, when a fuel support casting 406 is lifted, a small gap will be formed between bottom plate 44 and the fuel support casting 406. In this configuration, switches 86 will not be engage the fuel support casting 406, and therefore switches 86 will be closed. Switches 86 are arranged such that when they are closed, switches 86 will prevent air cylinder 82 from releasing. However, when a fuel support casting 406 has been set on a firm surface the slot and pin arrangement 121, 123 permit the FSC hooking mechanisms 70 to rise a small amount relative to frame 42, the bottom plate 44 is permitted to come into contact with fuel support casting 406, thereby opening switches 86. The open switches 86 permit air cylinders 82 to release when an operator seeks to release fuel support casting 406. FIG. 4A/4B are schematic drawings of a pivot bar 77 portion of a fuel support casting (FSC) hook mechanism 70 of the conventional grapple 40 of FIG. 1. Plunger 74 has a roller 75 (FIGS. 4A/4B) positioned at a distal end of plunger arm 74a which is driven vertically up and down relative to frame 42 by rod 83 of air cylinder 82 mounted on the top of guides 72 (see FIG. 3). Plunger roller 75 is arranged to engage a back surface of pivot bar 77. Guide roller 78 is connected to a back side of plunger arm 74a to run along guide 72. Thus, as can be best seen in FIG. 4A, when plunger 74 is extended to a lowered position, roller 75 engages a flat back surface of pivot bar 77 at a location below pivot 79. In this position, hook 80 is pushed outward (see FIG. 4A) to a position that engages a lip of the fuel support casting side flow orifice 406a (FIG. 14). When plunger 74 is raised to a withdrawn position (see FIG. 4B), roller 75 engages an inclined back surface portion of pivot bar 77 at a location above pivot 79, as shown in FIG. 4B. In this position, pivot bar 77 pivots in a counterclockwise direction about pivot 79 (see the difference between FIGS. 4A and 4B), such that hook 80 is pulled back toward guide 72. In this position (the position shown in FIG. 4B), hook 80 cannot engage a lip of the fuel support casting side flow orifice 406a. Plunger 74 has a substantially frustum shaped contact pad 76 that is designed to seat on a rim of a fuel support casting upper flow orifice 406c (FIG. 14) when air cylinder rod 83 strokes downward. That is, plunger contact pad 76 will seat on a rim of a beveled upper flow orifice 406c of fuel support casting 406. Contact pad 76 therefore provides a solid supporting surface that cooperates with hook 80 to hold a fuel support casting 406, independent of the rest of the grapple unit. Since plunger 74 can stroke down a variable distance, relative to hook 80, while still causing hook 80 to engage, this design can readily and affirmatively pick up a fuel support casting 406 regardless of a distance between a top of the fuel support casting 406 and a bend in the flow hole channel (see the position of upper low orifice 406c relative to side flow orifice 406a of FIG. 14). Guide rollers 78 serve to guide plunger 74 and support a reaction force of hook 80. Air cylinders 82 are operated by a pair of air lines (not shown) that are connected to grapple 40 from the refueling bridge. Center plate 45 (FIG. 3) has a pair of slotted keyways (not shown) through which air fittings for air cylinders 82 extend to provide a coupling for their associated air hose. The described grapple 40 has several advantages. One advantage is that it can be used with a fuel support casting 406 in place. Another is that it will work with control rods of any length. A third advantage is that, when it is used during a control rod moving operation, it can be used with a blade guide (that supports the control rod) seated on the fuel support casting 406. FIG. 5 is a perspective view of a conventional, temporary storage rack 150. Storage rack 150 includes a pair of substantially parallel troughs 152 that extend between a top plate 154 and a bottom plate 155. Each trough 152 has a shoe-shaped retaining bar 157 that extends across an open front of trough 152 with a seat 159 that is shaped to receive a socket of velocity limiter 29. Top plate 154 has a pivoted bail handle 161, a cruciform fuel support storage seat 163, a hook 165, a pair of opposing anti-rotation pins 166 and a spring loaded safety catch 167. Fuel support storage seat 163 and the anti-rotation pins 166 are provided to receive and position a fuel support, respectively. The pair of opposing anti-rotation pins 166 are provided so that a fuel support can be placed on storage rack 150 in one of two orientations. When a fuel support is properly positioned, the anti-rotation pin 166 will slide into a positioning slot (not shown) in bottom plate 44 of grapple 40. This will actuate air switch 133, which permits FSC hooking mechanisms 70 to release the fuel support casting 406. Bail handle 161, hook 165 and safety catch 167 are used for installation, securing and removal of storage rack 150. During installation, crane hook holds storage rack 150 by bail handle 161 and moves rack 150 into place. Spring loaded safety catch 167 is designed to latch onto one of the pressure vessel guide rods, and cooperates with two feet 160 and a centering pin 169 (which extend from the bottom surface of the bottom plate 155), to position storage rack 150. Specifically, pin 169 fits into a hole (not shown) in the guide rod bracket that extends between the shroud and the guide rod (not shown). Feet 160 seat on the upper rim of the shroud. It is contemplated that storage rack 150 will not be permanently installed within the reactor vessel. Rather, it would be installed during maintenance operations in which the control rods will be repositioned. Thus, bail handle 161 and hook 165 will be used for removing the storage rack as well. Suitable methods of installing, removing and repositioning control rods using the grapple 40 will now be explained. To remove a control rod that is currently installed, an operator stationed on the refueling platform manipulates a grapple hoist cable such that the grapple 40 is lowered into position directly over a selected control rod. When grapple 40 is positioned over an end of a control rod, guides 65 slide into upper flow orifices 406c to fine position grapple 40. As grapple 40 is lowered, bottom plate 44 of frame 42 will come to rest against the fuel support casting 406. As the hoist cable is further lowered, sliding bar 51 will slide relative to frame 42 until cage 57 carried by the sliding bar 51 contacts a top of the control rod bail handle 22. In this fully lowered position, distal ends of the fuel support mechanisms 70 will have slid into respective upper flow orifices 406c and bottom plate 44 will rest on the top of the fuel support casting 406. At the same time, control rod hooking mechanism 55 rests on bail handle 22. Air cylinders 62 and 82 are then actuated to pivot CRB hook 55 and FSC hooks 80 into place, respectively. Actuation of air cylinder 82 also serves to seat contact pads 76 into tapered upper flow orifices 406c of the fuel support casting 406. After the control rod release handle has been pulled and air cylinders 62 and 82 have been actuated, sliding bar 51 is lifted a small amount to verify that the control rod drive has been properly released. Thereafter, the grapple hoist cable can be lifted. When this occurs, the control rod blade 20 will be lifted before the fuel support casting 406 (due to movement of sliding bar 51, relative to frame 42). Thus, the operator can verify that grapple 40 has a good hold of the control rod blade 20. Thereafter, bracket 63 comes into contact with top plate 43, and the entire grapple 40 is lifted, which serves to simultaneously lift the control rod blade 20 and the fuel support casting 406 from a fuel channel. It is contemplated that the fuel support casting 406 will always be removed together with control rod blade 20. Therefore, when the control rod blade 20 is to be discarded after it has been removed, grapple 40 can be used to remove both the control rod blade 20 and the fuel support casting 406. The control rod blade 20 can then be lifted out of the pressure vessel and placed into the fuel pool. A new control rod blade 20 can then be picked up by grapple 40 and inserted into a selected core location together with the original fuel support casting 406 which may be continually held by grapple 40. If for any reason grapple 40 needs to be used for other purposes, fuel support casting 406 can be placed in an appropriate storage location which may be in the storage rack 150 or on the reactor floor. On the other hand, when the position of a control rod blade 20 is to be shifted about the core, both the fuel support casting 406 and the control rod blade 20 will be placed in storage rack 150. That is, the control rod blade 20 will initially be placed in one of the troughs 152. Thereafter, the fuel support casting 406 is placed on the storage seat 163. When the fuel support casting 406 is properly positioned over anti-rotation pins 166, the fuel support casting 406 can be released. Thereafter, grapple 40 will be positioned over a second control rod located at the position at which the first control rod is to be shifted to. The second control rod and its associated fuel support casting are then removed in the same manner as described above. The second control rod blade 20 is then placed in a second trough while the second fuel support casting 406 remains held by the grapple 40. The grapple 40 is then used to pick up the first control rod blade 20 from the storage rack. The first control rod blade 20, together with the second fuel support casting 406 are then inserted into the second channel. This process can be repeated as necessary to shift or replace all of the control rods that are to be moved. When a control rod blade is to be inserted into the position from which the fuel support casting on the storage rack came, the fuel support on the storage rack is picked up together with the selected control rod and placed in the corresponding channel. When the position of a control rod is to be switched within the reactor core, grapple 40 may be used to remove a control rod along with the fuel support casting and place it in the storage rack. A second control rod/fuel support is removed in a similar manner, and the second control rod is also placed in the storage rack. The second fuel support is retained and placed over the first control rod, which is grappled and moved to the second core location. The control rod and fuel support are placed in the core. The grapple is then used to grab the first fuel support from the storage rack, place it over the second control rod, grapple it, and move them both to the first cell location. This process or a variation using more than two control rods can be repeated until all of the control rods that are to be shifted have been moved. FIG. 6 is a perspective view of a grapple 200, in accordance with an example embodiment. The grapple 200 may be similar and/or identical to the grapple of FIG. 1 (notice several of the same reference characters in FIG. 6 and FIG. 1, identifying some of the many common components), but may additionally include a pair of control rod guide tube (CRGT) hooks 202 and a selector switch 201. Selector switch 201 may allow pneumatic control of the CRGT hooks 202 to be turned on or off, thereby allowing the function of CRGT hooks 202 to be turned on or off as desired, as described herein in more detail. FIGS. 6A/6B are side views of the grapple 200 of FIG. 8, in accordance with an example embodiment. CRGT hooks 202 may extend from a bottom of frame 42 at locations that oppose each other. That is to say, the “hook” portion 202f (shown in more detail, in FIG. 9) of each CRGT hook 202 faces away from each other, just as the FSC hooks 80 inside of guide 72 also oppose each other (and face away from each other). CRGT hooks 202 may be slideably connected to bottom plate 44 so that CRGT hooks 202 may have a range of motion (M) that is parallel to bottom plate 44. The range of motion (M) of each CRGT hook 202 may cause CRGT hooks 202 to expand and contract as CRGT hooks 202 move along bottom plate 44. Movement of the CRGT hooks 202 may be orchestrated to occur simultaneously, meaning that the CRGT hooks 202 may expand and contract in unison with each other. The range of motion (M) of CRGT hooks 202 may occur in a plane that is approximately perpendicular to a plane that exists containing the range of motion (M1) of FSC hooks 80 (as shown in FIGS. 4A/4B, FSC hooks 80 may retract and extend while swinging on pivot 79). FIG. 6C is a detailed view of the frame 42 of the grapple of FIG. 6, in accordance with an example embodiment. Bottom plate 44 may include diagonally-positioned through-holes 44a that allow each CRGT hook 202 to slide within bottom plate 44. Cylinder reaction 44b may be included along a side of each through-hole 44a. Cylinder reaction 44b may be a bracket that includes connection points for pneumatic air (both an inlet air connection, and an outlet air connection) that may be provided to both pipe fittings 204a1/204a2 (see FIG. 7) via flexible hose connections (not shown) to control movement of the CRGT hooks 202. FIG. 7 is a side view of a control rod guide tube (CRGT) hook 202, in accordance with an example embodiment. Each CRGT hook 202 may include two pipe fittings 204a1/204a2 that drive the operation of cylinder rod 204b (see the retracted position of cylinder rod 204b in FIG. 7E, and the extended position of cylinder rod 204b in FIG. 7F). Pipe fitting 204a1 may act as “air in,” when cylinder rod 204b is being extended, while pipe fitting 204a2 may act as “air out.” The “air in”/“air out” roles of the pipe fittings 204a1/204a2 may then be reversed, when cylinder rod 204b is being retracted. Hook body 202a may be a vertically extending long body with a distal end that curves (at offset 202b) to form a hook portion 202f of each CRGT hook 202. The hook portion 202f may have a horizontally extending piece 202c that projects away from offset 202b. The horizontally extending piece 202c may include an inner landing surface 202c2 that is a flat surface between offset 202b and back-off tab 202d. On a distal end of the horizontally extending piece 202c, an outer landing surface 202c1 may be provided, which may be a small, flat horizontal surface. Between the inner and outer landing surfaces 202c2/202c1 may be a back-off tab 202d that may be in the shape of a pointed, triangularly shaped nipple. The back-off tab 202d may have a longitudinal length that extends across the horizontally extending piece 202c to entirely separate the inner and outer landing surfaces 202c2/202c1 from each other. A length of the inner landing surface 202c2 of the horizontally extending piece 202c may be sized to be slightly longer than a thickness of a FSC side flow orifice 406a (see inner landing surface 202c2 supporting FSC side flow orifice 406a in FIG. 16H). A length of the outer landing surface 202c1 of the horizontally extending piece 202c may be sized to extend beyond the confines of a CRGT flow orifice 404a when the CRGT hook 202 engages control rod 400 (see outer landing surface 202c1 extending slightly beyond the lip of the CRGT flow orifice 404a in FIG. 16H). A width of back-off tab 202d may be sized to fit between fuel support casting 406 and control rod guide tube 404, to ensure that back-off tab 202d maintains some separation between fuel support casting 406 and control rod guide tube 404 in transit. FIG. 7A is a front view of the CRGT hook 202 of FIG. 9, in accordance with an example embodiment. Pipe fitting 204a1 (and similarly, pipe fitting 204a2, not shown in this drawing) may be facing one side of CRGT hook 202. This allows each pipe fitting 204a1/204a2 to face cylinder reaction 44b (FIG. 6C), with flexible hose (not shown) connecting pneumatic air from cylinder reaction 44b to the pipe fittings 204a1/204a2, without kinking of the flexible hose. A pneumatic cylinder 204 may be located near the top of CRGT hook 202, to drive the movement of cylinder rod 204b (FIG. 7F), and in turn provide movement for each CRGT hook 202 (see the CRGT hook 202 range of motion, M, in FIG. 8B). Pneumatic cylinder 204 may be housed in cylinder cradle 202e. Cylinder cradle 202e may include an overhang 202e4 and a bearing surface 202e on either side of the cylinder cradle 202e. Each bearing surface 202e may contact a side of through-hole 44a (FIG. 6C), while overhang 202e4 may rest on a top surface of bottom plate 44 (also FIG. 6C), allowing CRGT hook 202 to hang and slide within through-hole 44a of bottom plate 44. The front shape of hook body 202a may progressively taper toward the distal end of the CRGT hook 202 (i.e., near the hook portion 202f of hook 202). Back-off tab 202d may also be tapered, with a pointed flat upper surface 202d1 on a distal end of the back-off tab 202d. FIG. 7B is an overhead view of the CRGT hook 202 of FIG. 7, in accordance with an example embodiment. Notice that cylinder cradle 202e may hold pneumatic cylinder 204, while pipe fittings 204a1/204a2 project above pneumatic cylinder 204 and cylinder cradle 202e. FIG. 7C is a perspective view of the CRGT hook 202 of FIG. 7, with the pneumatic cylinder removed from the hook, in accordance with an example embodiment. Cylinder cradle aperture 202e3 (also shown in FIGS. 7E/7F) may be included in a rear position of an inner recess 202e2 of cylinder cradle 202e. FIG. 7D is a perspective view of the CRGT hook 202 of FIG. 7, in accordance with an example embodiment. FIG. 7D depicts, with better clarity, a tapered portion 202a1 of hook body 202a and a straight portion 202a2. The tapered portion 202a1, the straight portion 202a2, and the offset portion 202b of CRGT hook 202 allow the shape of hook 202 to conform to an inner curved flow channel (between upper flow orifice 406c and side flow orifice 406a of FIG. 14) of a fuel support casting 406. FIG. 7D also shows the tapered nature of back-off tab 202d, and in particular the pointed, flat upper surface 202d1 of back-off tab 202d. FIGS. 7E/7F are rear perspective views of the CRGT hook 202 of FIG. 7, with cylinder rod 204b in a retracted and extended position, respectively. Pneumatic air supplied to pipe fittings 204a1/204a2 may drive the movement of the cylinder rod 204b. Movement of the cylinder rod 204 is allowed via the existence of aperture 202e3 which penetrates cylinder cradle 202e. FIG. 8 is a close-up side view of the CRGT hook 202 installed on the grapple 200, in accordance with an example embodiment. Notice the location of cylinder cradle 202e and cylinder rod 204b that are centrally located within through-hole 44a (FIG. 6C) of bottom plate 44. FIG. 9 is a perspective view of the CRGT hook 202 installed on the grapple 200, showing the motion (M) of the CGRT hook 202, in accordance with an example embodiment. FIG. 9 shows CRGT hook 202 in a fully retracted position. FIG. 10 is another perspective view of the CRGT hook 202 installed on the grapple 200, showing the motion (M) of the CGRT hook 202, in accordance with an example embodiment. FIG. 10 shows CRGT hook 202 in a fully extended position. FIG. 11 is an overhead view of a conventional core plate 300. Fuel support channels 302 house control rods 400 (FIG. 15), which are not shown in FIG. 11. FIG. 12 is a detailed view of a conventional control rod blade 20 (CRB). The control rod blade 20 is similar to the control rod blade 20 of FIG. 5, but shown in more detail in this figure. Handle 22 is included at the top of the control blade 20, with a velocity limiter 29 included near the bottom of the control blade 20. As shown in FIG. 15, the control rod blade 20 is positioned lengthwise along a centerline of the overall control rod 400. FIG. 12A is a detailed view of the handle 22 of the conventional control rod blade 20 of FIG. 12. FIG. 13 is a detailed view of a conventional control rod guide tube (CRGT) 404. As shown in FIG. 15, the CRGT 404 forms a lengthwise outer shell of the overall control rod 400. FIG. 13A is a detailed view of the top of the conventional CRGT 404 of FIG. 13. Note that four equally spaced apart guide tube flow orifices 404a are located along the outer periphery of the CRGT 404. Alignment tabs 404b hold the CRGT 404 into place on core plate 300 within a respective fuel support channel, as shown in FIG. 15B. FIGS. 14/14A are perspective and overhead views of a conventional fuel support casting (FSC) 406. Four upper flow orifices 406c are included in each of four quadrants of the FSC 406. Four curved channels (not shown) exists within the FSC 406, which connect each upper flow orifice 406c with a respective side flow orifice 406a. Alignment guides 406b rest above the alignment tabs 404b (FIG. 13A) of the CRGT 404, when the control rod 400 is installed in core plate 300 (as shown in FIG. 15B). FIG. 15 is a cut-away view of a conventional control rod 400. The FSC 406 holds control rod blade 200 in position at the top of the control rod 400, as the majority of control blade 200 including velocity limiter 29 is housed in CRGT 404. FIG. 15A is a side view of the conventional control rod 400 of FIG. 15, installed in the conventional core plate 300 of FIG. 11. FIG. 15B is a top view of the conventional control rod 400 installed in the conventional core plate 300, as shown in FIG. 15A. Alignment pins 304 of core plate 300 are captured by FSC alignment guide 406b and CRGT alignment tab 404b, to ensure that control rod 400 does not rotate within core plate 300. Notice that FSC upper flow orifices 406c are located in each quadrant of FSC 406 that is subdivided by the control blades 20. FIG. 16 is a perspective view of a grapple 200 preparing to engage a control rod 400 installed in core plate 300, in accordance with an example embodiment. FIG. 16A/16B are detailed views of the CRB hook 55 of grapple 200 engaging the handle 22 of the control rod blade (CRB) 20, in accordance with an example embodiment. Cylinder 62 operating off of bracket 63 mobilizes CRB hook 55 to grasp handle 22. FIG. 16A shows CRB hook 55 in a retracted position, and FIG. 16B shows CRB hook 55 in a fully extended position (with hook 55 fully grasping handle 22). Once CRB hook 55 grasps handle 22, CRB hook 55 may then slightly pull CRB 20 up and out of FSC 406 (CRB 20 may be pulled out of FSC 406 by approximately ten inches), prior to grapple 400 then fully lifting control rod 400 out of core plate 300. The movement of CRB hook 55, shown in FIGS. 16A/16B, may occur in an identical manner as the movement of the conventional CRB hook 55, shown in FIGS. 5, 6A and 6B. FIG. 16C/16D are detailed views of a FSC hook of the grapple 200 engaging the FSC 406, in accordance with an example embodiment. FIG. 16C shows FSC hook 80 in a retracted position while FSC hook 80 operates within FSC 406. FIG. 16D shows FSC hook 80 in a fully extended position, as FSC hook 80 grips an edge of side flow orifice 406a of FSC 406. The movement of FSC hook 80, shown in FIGS. 16C/16D, may occur in an identical manner as the movement of the conventional FSC hook 80, shown in FIGS. 4A-4B. Notice that FSC hook 80 only grips the edge of side flow orifice 406a of FSC 406, but the distal end of FSC hook 80 stops short of touching or engaging the CRGT flow orifice 404a. FIGS. 16E/16F are detailed views of the CRGT hook 202 of the grapple 200 engaging the CRGT 404, in accordance with an example embodiment. FIG. 16E depicts CRGT hook 202 in a full retracted position, where cylinder rod 204b is retracted inside of cylinder cradle 202e (as shown in FIG. 7E). It should be understood that the shape of the tapered portion 202a1, the straight portion 202a2 and the hook portion 202f of the CRGT hook 202 conform to the curved flow channel of the FSC 406 (the channel between an upper flow orifice 406c and a side flow orifice 406a, shown in FIG. 14). FIG. 16F depicts CRGT hook 202 in a fully extended position, where cylinder rod 204b is fully extended from cylinder cradle 202e (as shown in FIG. 7F). Cylinder rod 204b may be attached to the bottom plate backstop 44c, and the cylinder rod 204b may use the backstop 44c as leverage to force the CRGT hook 202 toward the FSC side flow orifice 406a and CRGT flow orifice 404a. In the fully extended position, the inner landing surface 202c2 is located directly below a lip of the FSC side flow orifice 406a, and outer landing surface 202c1 is located directly below a lip of the CRGT flow orifice 404a. In the fully extended position, the outer landing surface 202c1 also extends slightly beyond the confines of a lip of the control rod guide tube flow orifice 404a (see also, FIG. 16H). The purpose behind the locations of the inner and outer landing surfaces 202c2/202c1 is explained in more detail, in FIG. 16H. It should be noted that the movement of the CRGT hook 202 (FIGS. 16E-16F), the FSC hook 80 (FIGS. 16C-16D) and the CRB hook 55 (FIGS. 16A-16B) may occur simultaneously, or they may occur one at a time, in any order. That is to say, the movements of hooks 55/80/202 are not tied to each other, meaning that they can operate independently of each other, by extending or retracting independently of any movement of the other hooks. However, in a preferred embodiment, movement of each pair of CRGT hooks 202 occur simultaneously (meaning, the two hooks 202 extend and retract at a same time, and adopt a same position, in unison with each other). Likewise, in a preferred embodiment, movement of each pair of FSC hooks 80 occur simultaneously (meaning, the two hooks 80 extend and retract at a same time, and adopt a same position, in unison with each other). FIG. 16G is a view of the grapple 200 and the top of control rod 400, after the grapple 200 has grasped the control rod 400, in accordance with an example embodiment. In this figure, FSC hook 80 is in a fully extended position (notice FSC hook 80 contacting the lip of FSC side flow orifice 406a). CRGT hook 202 is also in a fully extended position (notice back-off tab 202d and outer landing surface both extending beyond a lip of FSC side flow orifice 406a). Note that only one CRGT hook 202 and one FSC hook 80 may be seen in this figure. However, in the configuration of FIG. 16G, it should be understood that another CRGT hook 202 and another FSC hook 80 are also in a fully extended position as well, so that the weight of the FSC 406 and CRGT 404 are evenly distributed between both CRGT hooks 202 and FSC hooks 80. Additionally in FIG. 16G, CRB hook 55 has grasped handle 22 of the control rod blade 20, as shown in FIG. 16B (although the CRB hook 55 and handle 22 can not be seen in this figure). In the configuration, grapple 200 has now fully engaged the control rod blade 200, the FSC 406 and the CRGT 404, and grapple 200 may now lift all three components out of a respective fuel support channel 302 (see the fuel support channel, in FIG. 15B). As explained in more detail herein, if it is desired that grapple 200 grasp only control rod blade 20 and FSC 406 (and not CRGT 404), then CRGT hook 202 will be locked out by selector switch 201 such that CRGT hook 202 will remain in a retracted position prior to grapple 200 being lifted out of fuel support channel 302. FIG. 16H is a detailed view of the CRGT hook 202, after the CRGT hook 202 has grasped the CRGT 404, in accordance with an example embodiment. This figure depicts the interaction between the CRGT hook 202, FSC 406, and CRGT 404, once grapple 400 has started to pull the entire control rod 400 out of a respective fuel support channel 302 (see the fuel support channel, in FIG. 15B). Notice inner landing surface 202c2 contacting the lip of FSC side flow orifice 406a. Inner landing surface 202c2 is used to help support FSC 406, in conjunction with the FSC hooks 80. Outer landing surface 202c1 is also contacting the lip of CRGT flow orifice 404a. Outer landing surface 202c1 allows grapple 400 to extract CRGT 404 from fuel support channel 302 along with the control rod blade 20 and FSC 406. Back-off tab 202d, located between the inner and outer landing surfaces 202c2/202c1, may be inserted into a recess in between FSC 406 and CRGT 404 to maintain separation between the FSC 406 and CRGT 404 as the control rod 400 is extracted from fuel support channel 302 by grapple 400. FIG. 17 is a perspective view of a selector switch 201 and 5-way valve 203, in accordance with an example embodiment. The selector switch 201 and 5-way valve 203 may be mounted anywhere on grapple 400, and may be used to lock out use of the CRGT hooks 202, in the event that only the control rod blade 20 and FSC 406 (and, not CRGT 404) are to be extracted from a fuel support channel 302. FIG. 17A is an underneath view of the selector switch 201 and 5-way valve 203 of FIG. 17, in accordance with an example embodiment. In this embodiment, selector switch 201 is mounted to top plate 43. Selector switch 201 may have a switch stem 201b extending below top plate 43. Toggle 201a inserts into switch stem 201b, allowing toggle 201a to be shifted into one of two positions via an up or down movement of switch stem 201b, as described herein in more detail. FIG. 17B is a detailed view of the selector switch 201 of FIG. 17, in accordance with an example embodiment. Selector switch 201 may include a body 201d with a ball lock pin 201 intersecting the body 201d. Switch stem 201b may have a stem through-hole 201b1, allowing toggle 201a to penetrate the switch stem 201b. The crown 201b2 may be connected directly to switch stem 201b. FIGS. 17C/17D are side views of the selector switch 201 of FIG. 17, in accordance with an example embodiment. FIG. 17C shows the selector switch 201 in a “CRGT Circuit Opened” position, meaning that selector switch 201 is allowing pneumatic control air to reach CRGT hook 202. Ball lock pin 201c is located in the CRGT circuit open pin hole 201d2 of body 201d in this configuration, such that a gap exists between crown 201b2 and the top of body 201d. Because crown 201b2 is directly connected to switch stem 201b, the configuration of FIG. 17C causes toggle 201a to be pulled into an “up” position (see FIG. 17E). In FIG. 17D, selector switch 201 is a “CRGT Circuit Closed” position. In this configuration, CRGT hook 202 is locked out, such that pneumatic control air is not able to reach CRGT hook 202 to operate the CRGT hooks 202. Notice that crown 201b2 has traveled downward (see travel distance, T, of FIG. 17C), such that no gap exists between crown 201b2 and body 201d. Ball lock pin 201c is now in the CRGT circuit closed pin hole 201d1, causing switch stem 201b and toggle 201a (FIGS. 17A and 17E) to be shifted downward, thereby causing a supply of pneumatic air from 5-way valve 203 to CRGT hooks 202 to be turned off. FIG. 17E is a side view of the selector switch 201 of FIG. 17, in accordance with an example embodiment. In this figure, toggle 201 is shifted “up” (in a “CRGT Circuit Opened” position, associated with the selector switch 201 configuration of FIG. 17C). In this configuration, pneumatic air from the 5-way valve 203 is supplied to CRGT hooks 202, allowing the CRGT hooks 202 to function. FIGS. 17E/17F are schematics of the 5-way valve 203 of FIG. 17, in accordance with an example embodiment. The 5-way valve 203 may be used to supply pneumatic air to each of the CRB hook 55, FSC hooks 80 and CRGT hooks 202. For instance, as shown in FIGS. 17E/17F, port 4 may supply air to FSC hooks 80. Port 2 may supply air to CRB hook 55. Ports 1 and 3 may be used to supply air to CRGT hooks 202. Ports 1 and 3 may be closed, via the movement of toggle 201a (as shown in FIGS. 17C-17E), when grapple 200 is being used only to grasp control rod blade 20 and FSC 406, and not grasp CRGT 404. Example embodiments having thus been described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the intended spirit and scope of example 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.
055241310	abstract	A semiconductor device manufacturing SOR X-ray exposure apparatus wherein, after a mask and a semiconductor wafer are aligned, and SOR X-ray is used to transfer a semiconductor device pattern on the mask onto a resist on the semiconductor wafer. The apparatus includes a mirror unit and an exposure unit for exposing the wafer through the mask to the X-ray from the mirror unit. The mirror unit includes an X-ray mirror for diverging the X-ray in a desired direction, a first chamber for providing a desired vacuum ambience around the X-ray mirror and a first supporting device for supplying the X-ray mirror. The exposure unit includes a shutter for controlling the exposure, a mask stage for holding the mask, a wafer stage for holding the wafer, a second chamber for providing a desired He ambience around the mask stage and the wafer stage, a frame structure for mounting the mask stage and the wafer stage and a second supporting device for supporting the frame structure. By this, a more highly integrated semiconductor device can be produced.
	claims	1. A system for disposing of low-level radioactive waste, wherein the system comprises:at least one open-pit-mine, wherein the at least one open-pit-mine is substantially shaped as an inverted frustum that extends vertically downwards below a terrestrial surface of the Earth to a bottom the at least one open-pit-mine, wherein the at least one open-pit-mine has exterior surfaces that bound a volume from the bottom of the at least one open-pit-mine to a top of the at least one open-pit-mine;at least one water-dispersion-wellbore that begins at the bottom of the at least one open-pit-mine and extends substantially vertically downwards into at least one particular geologic formation, wherein the at least one water-dispersion-wellbore is configured to convey water from the volume to the at least one particular geologic formation;at least one cell located within the volume, wherein the at least one cell is configured to receive at least one unit of the low-level radioactive waste; andat least one fluid-transport-zone that is located within the volume and disposed between at least some of the exterior surfaces of the at least one open-pit-mine and the at least one cell, wherein the at least one fluid-transport-zone conveys water within the volume to an opening of the at least one water-dispersion-wellbore. 2. The system according to claim 1, wherein the system further comprises a protective-medium, wherein after the at least one cell has received the at least one unit of the low-level radioactive waste, at least some of the protective-medium is inserted into the at least one cell to fill in void spaces around the at least one unit of the low-level radioactive waste, wherein the protective-medium is configured to mitigate against migration of radionuclides away from the at least one unit of the low-level radioactive waste. 3. The system according to claim 2, wherein the protective-medium is comprised of carbon nanotubes and a foam cement slurry. 4. The system according to claim 2, wherein the protective-medium is comprised of one or more of: exfoliated vermiculite material aggregates, graphene derivatives, bentonite clays, bentonite fluids, tars, bitumen, heavy oils, complex hydrocarbons, retarders, or accelerators. 5. The system according to claim 1, wherein the top of the at least one open-pit-mine is substantially open. 6. The system according to claim 1, wherein the at least one water-dispersion-wellbore is substantially cased with casing to isolate water within the at least one water-dispersion-wellbore from a local water table that is located above the at least one particular geologic formation, wherein that casing radially surrounds at least a portion of the at least one water-dispersion-wellbore. 7. The system according to claim 1, wherein the at least one water-dispersion-wellbore runs from the opening to a distal portion, wherein the distal portion is located within the at least one particular geologic formation. 8. The system according to claim 1, wherein the at least one fluid-transport-zone is comprised of one or more of: at least one layer of crushed rock, at least one layer of gravel, at least one layer of both crushed rock and gravel, or a liner. 9. The system according to claim 8, wherein the liner is substantially water impermeable. 10. The system according to claim 1, wherein the system further comprises at least one filter, wherein the at least one filter is located proximate to the opening of the at least one water-dispersion-wellbore, wherein the at least one filter is operatively connected to the opening of the at least one water-dispersion-wellbore, wherein the at least one filter is configured to filter out at least some particulates from at least some of the water reaches the at least one water-dispersion-wellbore. 11. The system according to claim 10, wherein the at least one filter comprises one or more of: sand or gravel. 12. The system according to claim 1, wherein the system further comprises at least one water-injection-wellbore, wherein the at least one water-injection-wellbore extends from a distal portion of the at least one water-dispersion-wellbore, wherein the at least one water-injection-wellbore runs entirely within the at least one particular geologic formation, wherein the at least one water-injection-wellbore is operatively connected to the distal portion, wherein the at least one water-injection-wellbore is configured to discharge water into the at least one particular geologic formation. 13. The system according to claim 1, wherein the system further comprises at least one supplementary-water-collection-well, wherein at least one supplementary-water-collection-well is located within the volume, wherein supplementary-water-collection-well once installed within the volume is substantially oriented in a vertical configuration, such that a longitude of the at least one supplementary-water-collection-well is substantially vertical, wherein the at least one supplementary-water-collection-well is configured to transport received water to the at least one fluid-transport-zone. 14. The system according to claim 1, wherein vertical boundaries of the at least one cell are formed from one or more dividers. 15. The system according to claim 1, wherein the at least one cell is a plurality of cells, wherein at least some cells selected from the plurality of cells are vertically stacked upon each other within the volume. 16. The system according to claim 1, wherein the at least one cell when viewed from above has a shape that is substantially polygonal. 17. The system according to claim 1, wherein the at least one cell is a plurality of cells, wherein at least some cells selected from the plurality of cells are laid down in the volume in a horizontal layer configuration, with other cells selected from the plurality of cells being subsequently laid down in the volume in another horizontal layer configuration. 18. The system according to claim 1, wherein the system further comprises the at least one unit of the low-level radioactive waste. 19. The system according to claim 18, wherein the at least one unit of the low-level radioactive waste is in the form of a drum that contains an amount of the low-level radioactive waste. 20. The system according to claim 19, wherein the drum is crushed.
	description	This disclosure relates generally to ion implanters, and more specifically to a high voltage insulator that prevents instability in an ion implanter due to triple junction breakdown. A high voltage insulator is typically used in an ion implanter in locations along the beamline where there is a need for high voltage. For example, high voltage is necessary to extract an ion beam from an ion source. In particular, a high voltage insulator is used with an extraction system that receives the ion beam from the ion source and accelerates positively charged ions from within the beam as it leaves the source. Other locations where a high voltage insulator can be used in the beamline include an electrostatic lens that focuses the ion beam and an acceleration or deceleration stage that accelerates or decelerates the ion beam to a desired energy, respectively. Current high voltage insulator designs that are in use with a typical ion implanter are subject to triple junction breakdowns that lead to instability (e.g., high voltage instability, ion beam instability) and eventually failure of the implanter. A triple junction region in a high voltage insulator is the junction or region where three volumes having different electrical characteristics come together and thus the local electric field at the triple junction region is intensified due to the step change of the electrical characteristics at the triple junction region. The three volumes typically include a dielectric (e.g., insulator) that holds off high voltage, metal electrodes (e.g., metallic conductor), and a vacuum in the interior of the beamline. The dielectric and the metallic conductor together form the vacuum vessel to transport the ion beam and protect it from atmospheric pressure. An O-ring is sandwiched between the dielectric and the metallic conductor to provide a vacuum seal from atmospheric pressure. In addition, the O-ring allows the metallic conductor to be disassembled from the dielectric during the maintenance of the high voltage insulator. A vacuum seal interface gap is produced between the dielectric and the metallic conductor. The vacuum seal interface gap is a narrow or microscopic space containing many voids. The vacuum seal interface gap is located at exactly the same place where a triple junction region is located. During operation of the high voltage insulator, these voids formed in the vacuum seal interface gap or triple junction region not only have intensified local electric fields but also have poor vacuum pressure that promote electric discharge which makes the vacuum pressure even worse, triggering a secondary ionization. Eventually the secondary ionization will trigger a breakdown in a triple junction region that propagates along an inner surface of the dielectric until it reaches the opposite electrode and shorts out the power supply, resulting in ion implanter failure. Therefore, it is desirable to develop a high voltage insulator that can prevent triple junction breakdown that causes instability in an ion implanter. In a first embodiment, there is an apparatus for preventing triple junction breakdown. In this embodiment, the apparatus comprises a first metal electrode and a second metal electrode. An insulator is disposed between the first metal electrode and the second metal electrode. The insulator has at least one surface between the first metal electrode and the second metal electrode that is exposed to a vacuum. A first conductive layer is located between the first metal electrode and the insulator. The first conductive layer prevents triple junction breakdown from occurring at an interface of the first electrode, insulator and vacuum. A second conductive layer is located between the second metal electrode and the insulator opposite the first conductive layer. The second conductive layer prevents triple junction breakdown from occurring at an interface of the second electrode, insulator and vacuum. In a second embodiment, there is an apparatus for preventing triple junction instability in an ion implanter. In this embodiment, the apparatus comprises a first metal electrode and a second metal electrode. An insulator is disposed between the first metal electrode and the second metal electrode. The insulator has at least one surface between the first metal electrode and the second metal electrode that is exposed to a vacuum that transports an ion beam generated by the ion implanter. A first conductive layer is located between the first metal electrode and the insulator. The first conductive layer prevents triple junction breakdown from occurring at an interface of the first electrode, insulator and vacuum. A second conductive layer is located between the second metal electrode and the insulator opposite the first conductive layer. The second conductive layer prevents triple junction breakdown from occurring at an interface of the second electrode, insulator and vacuum. In a third embodiment, there is a method for preventing triple junction instability in an ion implanter. In this embodiment, the method comprises providing a first metal electrode; providing a second metal electrode; disposing an insulator between the first metal electrode and the second metal electrode, wherein the insulator has at least one surface between the first metal electrode and the second metal electrode that is exposed to a vacuum that transports an ion beam generated by the ion implanter; providing a first conductive layer located between the first metal electrode and the insulator, wherein the first conductive layer prevents triple junction breakdown from occurring at an interface of the first electrode, insulator and vacuum; and providing a second conductive layer located between the second metal electrode and the insulator opposite the first conductive layer, wherein the second conductive layer prevents triple junction breakdown from occurring at an interface of the second electrode, insulator and vacuum. Embodiments of this disclosure are directed to a high voltage insulator design that prevents triple junction instability in an ion implanter. In one embodiment, conductive layers or plates are placed between a dielectric (e.g., an insulator) and the metal electrodes (e.g., metallic conductor). With this design, one end of the insulator is joined to a first conductive layer to form a first triple junction using a joining technique that minimizes formation of the voids in the first triple junction region, while the first conductive layer is attached to the first metal electrode. A first O-ring is sandwiched between the first conductive layer and the first metal electrode to seal the vacuum from the atmospheric pressure. This forms a first vacuum seal interface gap at the space between the first conductive layer and the first metal electrode. Another end of the insulator is joined to a second conductive layer to form a second triple junction using a joining technique that minimizes formation of the voids in the second triple junction region, while the second conductive layer is attached to the second metal electrode. A second O-ring is sandwiched between the second conductive layer and the second metal electrode to seal the vacuum from the atmospheric pressure. This forms a second vacuum seal interface gap at the space between the second conductive layer and the second metal electrode. Because the vacuum seal interface gaps now are separated from the triple junction regions, gases that used to be trapped in the voids formed at the triple junction regions, are trapped in the spaces between the first conductive layer and the first metal electrode or between the second conductive layer and the second metal electrode having the same electric potential, and do not have an opportunity to initiate a breakdown that leads to failure of the ion implanter. FIG. 1 shows a front view of a cross-section of a high-voltage insulator 10 according to the prior art. The high-voltage insulator 10 shown in FIG. 1 is for use in an ion implanter. In particular, the high voltage insulator 10 is used in an extraction system that extracts an ion beam from an ion source. Although the description that follows for the high voltage insulator 10 shown in FIG. 1 and the insulator design that relates to this disclosure (see FIGS. 3 and 4) is directed to an extraction system in an ion implanter, the scope of this disclosure is applicable to other components within the beamline of an ion implanter that need a high voltage. As mentioned above, other locations where a high voltage insulator can be used include an electrostatic lens, acceleration stage or deceleration stage. Referring back to FIG. 1, the high voltage insulator 10 includes a vacuum 12 formed within an insulator 14, anode electrode 16 and a cathode electrode 18. In one embodiment, the insulator 14 is a dielectric while the anode electrode 16 and the cathode electrode 18 are metal electrodes. As shown in FIG. 1, the insulator 14 separates the anode electrode 16 from the cathode electrode 18 in order to hold a high voltage that is necessary to extract ions from an ion source. Stress relief features 20, which are metal components such as aluminum, reduce electrical stress at triple junction regions, which are interfaces where the vacuum 12, insulator 14, anode electrode 16 or cathode electrode 18 meet. In particular, the stress relief features 20 function to reduce the electric field that intensifies at the triple junction regions. O-rings 22 are positioned between the anode electrode 16 and one end of the insulator 14 and between the cathode electrode 18 and another end of the insulator to provide vacuum seals from atmospheric pressure 24. The O-rings 22 are typically accommodated in a groove that allows assembly of the insulator 14 to the anode electrode 16 and cathode electrode 18 to be clamped tight by fasteners (not shown) while producing an appropriate compression for a vacuum seal. The high voltage insulator 10 of FIG. 1 operates by maintaining a high voltage across the insulator 14, anode electrode 16 and cathode electrode 18 in order to extract ions from an ion source in the form of an ion beam. The ion beam moves through the vacuum 12 keeping its polarity because atmospheric pressure from the atmosphere 24 is sealed off. Although the high voltage insulator 10 of FIG. 1 utilizes stress relief features 20 to reduce the electric field at the triple junction regions, these features are not very effective and eventually breakdown will occur at the triple junction regions and lead to failure of the ion implanter. The root cause for the breakdown at the triple junction regions in the high voltage insulator 10 is due to a first vacuum seal interface gap formed between the insulator 14 and the anode electrode 16 at one end and a second vacuum seal interface gap formed between the insulator 14 and the cathode electrode 18 at the other end, which are both located at the exactly same places where the triple junction regions are located. As mentioned above, the vacuum seal interface gap is a narrow or microscopic space that contains many voids, which are also in the triple junction regions. Because of the extreme aspect ratio of the vacuum seal interface gaps, the volume associated with the voids formed in each vacuum seal interface gap are poorly evacuated. From the perspective of the overall vacuum system used in the ion implanter, the volume associated with these voids are so small that trapped gas that slowly leaks out is essentially a negligible gas load that does not significantly increase pressure. From the perspective of the high voltage triple junctions, the inventors have ascertained that this situation exposes a critical weakness in the conventional design of the high voltage insulator 10. In particular, if high voltage operation is initiated as soon as possible after vacuum conditions have been established, then the gas in this trapped volume will still be slowly leaking out, but creating very local high pressures in exactly the worst place having the local electric field intensified (i.e., triple junction regions). Such local pressures may reach the Paschen minimum where the mean free path of charged particles is just sufficient to allow them to gain enough energy to initiate a secondary ionization. Consequently, breakdown occurs across the channel formed in the triple junction regions between the insulator 14 and the anode electrode 16 or cathode electrode 18, despite the presence of the relief features 20. Furthermore, the local vacuum pressure in the triple junction regions rises due to the outgassing associated with the breakdown, which in turn fuels the secondary ionization and the breakdown. The result of this positive feedback loop is that this initial breakdown causes the insulator 14 to develop a carbonized layer that is a resistive conductor. This initiates “tracking” because the tip of such a carbonized region will cause an electric field concentration at the triple junction regions, resulting in the breakdown propagating along the inner surface of the insulator 14 until it reaches the opposite electrode (i.e., anode electrode 16 and cathode electrode 18) and shorts out the power supply leading to failure of the ion implanter. FIG. 2 shows a more detailed schematic illustrating the triple junction region of the high-voltage insulator 10 shown in FIG. 1. As shown in FIG. 2, a vacuum seal interface gap 26 is formed at each triple junction region 28. During a high voltage operation, the local electric field is intensified in the vacuum seal interface gaps 26 due to the step change of the electrical characteristic in the triple junction regions 28 that cause an electric field concentration in the gaps 26. This intensified electric field in each localized vacuum seal interface gap 26 detaches the charged particles (absorbed gases, deposited contaminants) from one surface of the vacuum gap 26, which impinge with sufficient energy on the other surface of the gap to trigger a secondary emission of charged particles leading to positive feedback. As mentioned above, gas trapped in the space associated with the vacuum seal interface gaps 26 will slowly leak out and create a very high pressure in this volume. Such local pressures may reach the Paschen minimum where the mean free path of the charged particles is just sufficient to allow them to gain enough energy to initiate a secondary ionization in the localized vacuum seal interface gaps 26. Consequently, breakdown occurs across the vacuum seal interface gaps 26 and the local vacuum pressure in the gaps rises due to the outgassing associated with the breakdown, which in turn fuels the secondary ionization and the breakdown. This initial breakdown results in the consequential breakdown that propagates along the inner surface of the insulator 14 until it reaches the opposite electrode (i.e., anode electrode 16 or cathode electrode 18). The inventors to this disclosure have discovered that effects from triple junction breakdown can be avoided by separating the triple junction regions 28 from the vacuum seal interface gaps 26. FIG. 3 shows a schematic of a high voltage insulator 30 according to one embodiment of this disclosure that separates the triple junction regions from the vacuum seal interface gaps. As shown in FIG. 3, the high voltage insulator 30 includes a first conductive layer 32A between one end of the insulator 14 and the anode electrode 16 and a second conductive layer 32B between the opposite end of the insulator and the cathode electrode 18. With this configuration, one end of the insulator 14 is joined to the conductive layer 32A using a joining technique to form the first triple junction at the joint between the insulator 14 and the conductive layer 32A. The joining technique minimizes formation of the voids in the first triple junction region while the conductive layer 32A is attached to the anode electrode 16. An O-ring 22 is sandwiched between the conductive layer 32A and the anode electrode 16 to seal the vacuum from the atmospheric pressure. This forms a first vacuum seal interface gap at the space between the conductive layer 32A and the anode electrode 16. Another end of the insulator 14 is joined to the conductive layer 32B using a joining technique to form a second triple junction at the joint between the insulator 14 and the conductive layer 32B. The joining technique minimizes formation of the voids in the second triple junction region while the conductive layer 32B is attached to the cathode electrode 18. Another O-ring 22 is sandwiched between the conductive layer 32B and the cathode electrode 18 to seal the vacuum from the atmospheric pressure. This forms a second vacuum seal interface gap at the space between the conductive layer 32B and the cathode electrode 18. FIG. 4 shows a more detailed schematic illustrating the triple junction regions of the high-voltage insulator of FIG. 3. As shown in FIG. 4, a first triple junction region 36A is formed at the joint between the insulator 14 and the conductive layer 32A. A first vacuum seal interface gap 34A is formed in the space between the conductive layer 32A and the anode electrode 16. A second triple junction region 36B is formed at the joint between the insulator 14 and the conductive layer 32B. A second vacuum seal interface gap 34B is formed in the space between the conductive layer 32B and the cathode electrode 18. Thus, the triple junction regions 36A and 36B are now separated from the vacuum seal interface gaps 34A and 34B, respectively. Because there is no microscopic gap between the conductive layers 32A and 32B and the insulator 14, and the gaps between the conductive layers 32A and 32B and the insulator 14 are smaller than the molecular size of gases, the joints between the conductive layers and the insulator 14 also seal the vacuum from atmospheric pressure. Since the triple junction regions 34A and 34B are formed at the joint between the conductive layers 32A and 32B and the insulator 14 there is no gap at the triple junction regions any more, which greatly reduces the local electric field at the triple junction regions. In one embodiment, the conductive layers 32A and 32B are formed by doping metal particles into the insulator 14. As an example, the metal particles can include aluminum. The metal particles are doped into the insulator 14 by using well-known doping techniques. In another embodiment, the conductive layers 32A and 32B are deposited on the insulator 14 using well-known deposition techniques. In another embodiment, the conductive layers 32A and 32B are bonded onto the insulator 14 so that there is no trapped void volume. Gluing (e.g., applying an epoxy) is only one example of an approach that can be used to bond the conductive layers 32A and 32B to the insulator 14. Those skilled in the art will recognize that other joining techniques may be used to join the conductive layers 32A and 32B to the insulator 14 at an atom level without a microscopic gap produced between the conductive layers and the insulator 14. Each of the above-described techniques for forming the conductive layers 32A and 32B has a commonality in that the insulator 14 and the conductive layers are joined together in the atomic level to form the triple junction so that there is no microscopic gap between the insulator 14 and the conductive layers. Because the triple junction regions in the extraction system of FIGS. 3 and 4 are separated from the vacuum seal interface gaps that are formed in the space between the conductive layer 32A and the anode electrode 16 and the space between the conductive layer 32B and the cathode electrode 18, the gases that used to be trapped at the triple junction regions now are trapped in the space 34A between the conductive layer 32A and the anode electrode 16 and the space 34B between the conductive layer 32B and the cathode electrode 18; there is no microscopic gap at the triple junctions 36A and 36B. Because the conductive layer 32A and the anode electrode 16 or the conductive layer 32B and the cathode electrode 18 have the same electrical potential, the trapped gases have no opportunity to initiate a secondary ionization and trigger a triple junction breakdown that will cause voltage or ion beam instability and subsequent failure of an ion implanter. It is apparent that there has been provided with this disclosure a high voltage insulator that prevents instability in an ion implanter due to triple-junction breakdown. While the disclosure has been particularly shown and described in conjunction with a preferred embodiment thereof, it will be appreciated that variations and modifications will occur to those skilled in the art. Therefore, it is to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.
051851040	description	PREFERRED EMBODIMENTS OF THE INVENTION FIG. 1 is a conceptual view of an apparatus used for practising the method of the present invention. The apparatus is equipped with a heat-treatment unit 10 and a plurality of cooling/collecting units 12a, . . . , 12n connected to the former. The heat-treatment unit 10 includes a heating vessel 14 and a heat-generation member 16. A feed port 18 for a reducing agent is provided at the upper part of the heating vessel 14 and a vapor passage 20 is interposed between the vessel 14 and the cooling/collecting unit 12a. A heat-generation and insulating member 22 is fitted around the vapor passage 20. The heating vessel 14 may be made of a refractory metal such as tungsten or a ceramic material such as alumina or high chromium refractory brick, depending on the heat-treatment temperatures. Besides external heating by supplying power to the heat generation member 16 shown in FIG. 1, high-frequency heating, microwave heating, heating by directly flowing electric current through the high-level radioactive waste or the like may be employed as the heating method. It is also important to utilize effectively the heating due to the decay heat of the high-level radioactive waste to be treated. The high-level radioactive waste 24 to be treated is charged into the heating vessel 14 and heated. This radioactive waste 24 is, for example, a calcined material obtained by heating a nitric acid solution generated from the reprocessing step of the spent nuclear fuels to evaporate the moisture and nitric acid. The heat-treatment in the heating vessel can of course be carried out continuously from the state of the nitric acid solution. The calcined material is heated to about 500.degree. C. to about 3,000.degree. C., more preferably to about 1,000.degree. C. to about 2,500.degree. C. The elements contained in the calcined material are vaporized due to heating at their sublimation or boiling points in accordance with their chemical forms and are sent to the cooling/collecting units 12a, . . . , 12n through the vapor passage 20. Each of these elements that are vaporized is individually cooled and collected by each of cooling/collecting units 12a, . . . , 12n whose temperature is controlled so as to correspond to a sublimation or boiling point of each compound or element. Though heating may be carried out at a normal pressure, it is preferably carried out under a reduced pressure from the aspect of energy efficiency because the sublimation or boiling point drops and heat-treatment can be made at a lower temperature. In a preferred embodiment of the present invention, those elements which sublimate or boil in the form of oxides are heat-treated under a normal or reduced pressure and separated in the first stage treatment. The remaining high-level radioactive material is then heated in the second stage treatment while a reducing agent is introduced through the feed port 18 to reduce the radioactive material and to separate those elements which sublimate or boil in the form of metal. Finally, the resultant residue inside the heating vessel 14 is recovered. Hydrogen gas, carbon, carbon monoxide or the like may be used as the reducing agent to be introduced through the feed port 18. The discharge method of the residual molten material 25 from the heating vessel 14 may be of a bottom flow system such as shown in FIG. 2 or of an overflow system such as shown in FIG. 3. In either case, the residual molten material 25 is discharged into a vessel 26 for solidification and is left for cooling to obtain a highly volume-reduced solidified material. EXAMPLE 1 A simulated nitric acid solution of a high-level radioactive waste in which radioactive nuclides were simulated by stable elements was prepared and was subjected to evaporation treatment to obtain a calcined material. The calcined material was then heated and reduced at a high temperature of 1,000.degree. C. for 4 hours in a mixed gas stream of H.sub.2 -He(1:4). In the interim, Te, Cd, Se, Cs and Na were deposited in the cooling/collecting units and could be collected. The respective temperatures in the cooling/collecting units with respect to these elements were 200.degree. to 600.degree. C. for Te, 200.degree. to 300.degree. C. for Cd, about 600.degree. C. for Se, 900.degree. to 1,000.degree. C. for Cs and 600.degree. to 1,000.degree. C. for Na. EXAMPLE 2 The calcined material obtained after the heating and reducing treatment at the high temperature in Example 1 was further heat-treated at 850.degree. to 1,050.degree. C. in a vacuum. It was confirmed that Pd and Ru were deposited in the cooling/collecting units. As is apparent from the foregoing, according to the method of the present invention, the high-level radioactive waste is heated, or reduction-heated, at a temperature to vaporize part of the elements contained in the radioactive waste and the resultant vapor was separated and collected. Therefore, in comparison with the prior art methods described hereinbefore, the method of the present invention has simplified treating steps, and does not need to add any special reagent or ion-exchange resin in the subsequent reprocessing or solidification step. Furthermore, since the collected elements are solids in the form of oxides or metals, they can be used as radiation sources or valuable metals, and can be subjected to transmutation without the need for complicated secondary treatment. In addition, the solidified material obtained by the present invention hardly contains additives other than the nuclear fission products and actinides and has an extremely smaller occupying volume for storage and disposal than the conventional solidified materials and can drastically reduce the costs for storage and disposal. The solidified material can preferably be used as a radiation source for nuclear transformation by neutron irradiation, since its volume is small and the irradiation efficiency is high. Although the present invention has been described with reference to the preferred embodiments thereof, many modifications and alterations may be made within the scope of the appended claims.
	summary
	claims	1. Apparatus for monitoring pressure in a chamber, comprising, an ion source which produces an ion beam; an ion collector which collects the ion beam to produce a beam current; an ammeter for continuously; measuring the beam current; a pressure gauge which measures the pressure of the chamber in a series of discrete measurements; and a data processor which combines the measured beam current and the measured gauge pressure to continuously determine the pressure in the chamber. 2. The apparatus of claim 1 , wherein the data processor combines the measured beam current and the measured gauge pressure by using the most recently measured gauge pressure as a base pressure and using the beam current to determine deviation from the base pressure. claim 1 3. The apparatus of claim 1 , further comprising orthogonal acceleration means for deflecting the ion beam to perform time-of-flight mass spectrometry. claim 1 4. The apparatus of claim 1 , wherein the series of discrete measurements are taken at a frequency not greater than about 100 Hz. claim 1 5. The apparatus of claim 1 , wherein the series of discrete measurements are taken at a frequency not greater than about 1 Hz. claim 1 6. The apparatus of claim 1 , wherein continuously monitoring beam current comprises measuring beam current at a frequency of at least 1 kHz. claim 1 7. The apparatus of claim 1 , wherein continuously monitoring beam current comprises measuring beam current at a frequency of at least 10 kHz. claim 1 8. The apparatus of claim 1 , wherein continuously monitoring beam current comprises measuring beam current at a frequency of at least 50 kHz. claim 1 9. The apparatus of claim 1 , wherein the ion beam is a component of a mass spectrometer. claim 1 10. A method of monitoring pressure in a chamber having a pressure gauge, an ion source and an ion collector, the ion source producing an ion beam which is collected by the ion collector to produce a beam current, comprising, monitoring the pressure gauge to determine a discrete series of base chamber pressure measurements; continuously monitoring the beam current; and using the beam current and the base chamber pressure measurements to continuously determine a corrected chamber pressure measurement. 11. The method of claim 10 , wherein the corrected chamber pressure measurement is determined by combining the measured beam current and the measured gauge pressure by using the beam current to determine deviation from the most recently measured base chamber pressure. claim 10 12. The method of claim 10 , further comprising using the determined corrected chamber pressure measurement as input to an automated process control system. claim 10 13. The method of claim 10 , wherein the series of base chamber pressure measurements are taken at a frequency not greater than about 100 Hz. claim 10 14. The method of claim 10 , wherein the series of base chamber pressure measurements are taken at a frequency not greater than about 1 Hz. claim 10 15. The method of claim 10 , wherein continuously monitoring beam current comprises measuring beam current at a frequency of at least 1 kHz. claim 10 16. The method of claim 10 , wherein continuously monitoring beam current comprises measuring beam current at a frequency of at least 10 kHz. claim 10 17. The method of claim 10 , wherein continuously monitoring beam current comprises measuring beam current at a frequency of at least 50 kHz. claim 10
055132332	abstract	Improved operability and economy of a nuclear reactor can be obtained by attaining a mixing of the flows of coolant in the lower plenum of the fuel assemblies of the nuclear reactor, a high flow stability of the two-phase flow in the fuel assemblies and a small pressure loss in the core. To achieve this, there is provided a coolant guide tube 60 that communicates with the inside of the fuel support piece 12 inserted in the control rod guide tube and the passage 16, wherein there is formed a coolant guide passage 61 along which coolant descends in the area outside of the coolant guide tube in the fuel assemblies from opening 79. The coolant guide passage along which the coolant descends from the opening is formed in an area outside of the coolant guide tube in the fuel support piece.
042657075	summary	This invention concerns a method for the separation of nuclear fission and activation products from a gas containing the same and apparatus for carrying out the method in and about a reactor building of a gas-cooled nuclear reactor. The process of this invention is particularly intended to make possible the separation of fission and activation products that occur within the containing walls of gas-cooled high temperature reactors in the case of serious so-called "hypothetical malfunctions," as malfunctions with small likelihood of occurrence are called. Nuclear fission or activation products can be set free in the rooms of the reactor building, with a large part of the space in the reactor building becoming radioactively contaminated, as a consequence of a serious hypothetical malfunction in which, after failure of the emergency cooling system, gas conduit pipes, or other components of a gas-cooled high-temperature reactor, burst. Nuclear fission and activation products contained in the gas atmosphere do lose their activity by physical and chemical degeneration processes, but the radionuclides remaining in the gas atmosphere, nevertheless, are a great danger to the enviroment. This is particularly the case if, as the result of leakages in the outer wall structure of the reactor building resulting from the malfunction, nuclear fission and activation products can escape into the outside environment. The requirements for separation of the nuclear fission and activation products, in addition to physical and chemical boundary conditions for the degeneration processes, depend above all on the geometrical dimensions and shapes of available space enclosed by the reactor building, particularly the ratio of surface of the enclosed space to the volume of the building. The liberated fission and activation products are present in the form aerosols, partly even in elemental form, which is to say atomic or molecular, so that the settling velocity for the fission and activation products resulting from diffusion and sedimentation are greatly delayed compared to the desired settling rates. In order to increase the settling rate, it is known from German published patent application No. OS 20 50 152 to innoculate the cooling stream with inactive isotopes of the fission and activation products that are produced in order to bind these fission and activation products, that might penetrate into the cooling medium circulation path of a nuclear reactor facility. This process, however, requires, independently from the occurrence of a malfunction, a continuous addition of dilute solutions containing the inactive isotopes, even during normal operation of the reactor. In the case of water-cooled nuclear reactors, it is known, after the fracture of a part of an apparatus or a pipeline of the reactor, to condense the vapor coming out of the fracture quickly by squirting in condensation nuclei, such as carbon dioxide snow or silver iodide, and in this way to bind the escaping radioactive substances (see German published patent application OS No. 20 57 593). For gas-cooled high-temperature reactors, the addition of such water condensing nuclei is either useless or uneconomic, however, because the gases escaping from the cooling medium circulation path in most malfunctions are dry gases. In the case of gas-cooled high-temperature reactors, filter systems are provided in the air circulation system of the reactor building, by which the fission and activation products are intended to be separated after occurrence of the malfunction by drawing off the atmosphere by suction from the radioactively contaminated chambers. There is the disadvantage, however, that such installations, as the result of their technically limited start-up and heat capacity filter out the liberated fission and activation products only relatively slowly and, on account of their dependence upon the supply of external energy--according to the gravity of the malfunction--are under certain conditions not at all capable of going into operation. THE PRESENT INVENTION It is an object of the invention to provide a process for separation of nuclear fission and activation products from a gas atmosphere by which high settling rates for the products contained in the gas atmosphere are obtainable, without the necessity of withdrawing the gas atmosphere out of the radioactively contaminated chambers or spaces. Briefly, at least 0.5 kilogram, preferably more than one kilogram per 50 m.sup.3 of atmosphere volume, of dust particles having a grain size distribution with an average particle size between 0.3 and 5 .mu.m is introduced in fine dispersion into the gas atmosphere. By "average particle size" is meant the particle size average value that is obtained as the characteristic size d' of the dust particle accumulation at the intersection point of the RRS straight line for a residue value R=36.8% in the grain size matrix according to Rosin-Rammler-Sperling. See "Verfahrenstechnik" [process technology] by Kiesskalt, published by Carl Hanser Verlag, Munich, 1958, pp. 61ff. By means of the dust particles (i.e., fine dry particles), the surface available for the settling of the fission and activation products in radioactively contaminated spaces is substantially magnified. At the same time, in the case of homogeneous particle distribution in the spaces in question, the critical free path length for the adsorption or settling of the fission and activation products is drastically reduced, and these fission and activation products are bound to the surface of the dust particles. This advantageously leads to a substantial increase of the settling or adsorption velocity which now is no longer dependent on the magnitude of the fission and activation product itself, but rather upon the size of the dust particles. The limits of the average particle diameter of the aggregate cloud of particles, therefore, are determined at the low extremity by the desired settling or adsorption velocity and at the upper extremity by the distribution of the particles and the aerosol formation in the gas atmosphere in the radioactively contaminated space. The binding of the fission and activation products to the dust particles diminishes at the same time the probability of escape of fission and activation products from leaks in the outer wall structure of the reactor building. As a further development of the method of the invention, the dust particles that are introduced comprise ceramic materials that are inert with respect to oxygen. Suitable dust size particles of this type consist of bentonite or clay. Cement or silica gel powders are also useable. The so-called extinguisher powders are preferred, these being powders commonly used in fire fighting. Graphite dust, because of its adsorptive capability, is also useable for inert gas atmospheres in the reactor building. In this case it is necessary to blow the material into the gas atmosphere by means of an inert gas in order to prevent explosions of the graphite dust. For carrying out the process according to the invention in a reactor building of a gas-cooled nuclear reactor having an outer pre-stressed concrete wall structure equipped with a liner, apparatus with the following features is provided according to the invention: The outlet of a dust hopper container feeds into a pneumatic feed line for drawing off dust particles stored in the container. The pneumatic feed line passes through the pre-stressed concrete wall structure and at its extremity outside of the wall structure is connectable to gas compression equipment that is situated in the neighborhood of the reactor building. The end portion of this pneumatic feed line that leads into the internal space of the reactor building has at least one dusting nozzle, and, preferably, several of them. The apparatus according to the invention, is advantageously capable of being put into operation within the reactor building independently of the apparatus destroyed as the result of the malfunction that has produced the radioactive contamination. To this extent, therefore, a passive safety system is provided. It is useful to locate the dust hopper also outside of the reactor building, so that the quantity of dust to be introduced into the reactor building can, from time to time, be increased beyond the amount contained in the hopper by way of supply. As mentioned before, in order to prevent dust explosions in the use of graphite dust, inert gas should be introduced as the compressed gas for the pneumatic feed. A homogeneous distribution of dusting material and aerosol formation in radioactively contaminated spaces is enhanced by providing a number of feed ducts or feed duct branches leading to dusting nozzles in the internal space and which are uniformly distributed over the ceiling surface of the reactor building.
	abstract	An outer filter removal tool for a boiling water reactor control rod drive that uses a mechanical advantage obtained through the use of lead screw threads to pull the outer filter off of the control rod drive. Fingers on the tool are closed around the upper flange of the outer filter by sliding a collar over the outwardly biased fingers. A shaft extending through the tool is rotated which in turn extends a push plate against the control rod drive index tube causing the fingers to pull against the upper flange on the outer filter until the filter is freed from the control rod drive. The tool will hold the filter in place until affirmatively released for proper disposal.
	description	FIG. 2 depicts the inventive device with additional auxiliary electrodes (9a, 9b) to increase the conversion efficiency or the radiation yield. A radiation emitting pinched plasma (11) forms in the gas-filled space (7) between the electrodes (1, 2), to which voltage is applied. On the side of the cathode (1) facing away from the space (7) there is an auxiliary electrode (9a), by means of which the sparking field strength of the gas discharge can be increased. This in turn allows an operation at higher gas pressures at higher radiation yield. The auxiliary electrode (9a) exhibits in operation a positive potential with respect to the cathode (1). Furthermore, between the main electrodes there is an auxiliary electrode (9b) to provide a longer pinched plasma column (11). Studies have shown that the plasma column (11) does not project or projects only slightly into the openings (3, 8) of the main electrodes, and thus in the case of a cylindrically symmetrical design of the openings only a small solid angle is available for the radiation decoupling. Thus, the cylindrically symmetrical opening (3) in this embodiment exhibits a diameter of 10 mm, with which, given the specified thickness of the electrodes, an observer could still see the plasma at an angle of xcex1=14 degrees relative to the axis of symmetry (5). Therefore, to increase the radiation yield the opening (8) is designed conically. In the case of the conical opening (8) the plasma (11) can still be recognized by the observer (12) at an angle of xcex1=60 degrees relative to the axis of symmetry (5). Thus, when the same energy is fed into the plasma, the result is a decoupled radiation intensity, which, compared to the case of the cylindrically symmetrical opening, is larger by approximately a factor of 20. FIG. 3 depicts in principle the same electrode configuration as in FIG. 2, but without the auxiliary electrodes. In addition, there are auxiliary openings (13a, 13b) for the gas inlet and/or the gas outlet from the area (14) of the hollow cathode (1). Thus, the discharge gas, such as xenon, oxygen or SF6, which is required for the gas discharge, can be admitted through the openings (13b). Said gas is ignited in the space (7). In the rearward areas of the electrode system, which are illustrated in FIG. 3, there is a gas with slight absorption, like helium or hydrogen. This gas, which is transparent to the generated radiation, is admitted through the openings (13a) into the area (14). The openings (13a) for admitting the transparent gas are farther away from the opening (8) than the openings (13b) for admitting the discharge gas. Thus, the light gas is first in that part of the area (14) of the cathode (1) that faces the x-ray gate (10); and the heavier discharge gas is in that part of the area (14) that faces away from the protecting glass (10) or in the vicinity of the opening (8). At this stage this procedure has two possibilities. First, both gases can be siphoned off in such a manner through openings, which are not shown in FIG. 3, in the area of the gas-filled space (7) that the result is a thorough mixing of both types of gases. The advantage lies in the fact that a higher plasma particle density can be obtained in the plasma channel located in the electrode space (7). As an alternative a part of the openings (13a) can be used in such a manner by initiating a laminar flow of the light gas in the rearward areas of the electrode system that thorough mixing is largely avoided by siphoning off the light gas. Thus, the light gas remains permanently in that part of the area (14) that faces the x-ray gate (10). However, this light gas absorbs the radiation significantly less than the discharge gas so that a higher radiant power is available to the user. Another possibility for using the openings (13a, 13b) consists of admitting the discharge gas not through the openings (13b), but rather through the openings, which are not shown in FIG. 3, in the area of the gas-filled space (7) or the anode (2) and siphoning off through the openings (13b). The light gas or transparent gas is admitted in turn through the openings (13a). These designs show that the openings (13a) can be used both to admit and to discharge the discharge gas(es); and the openings (13a) can be used only to admit the light gas(es). FIG. 4 depicts an embodiment of the inventive device, wherein the electrodes (1, 2) exhibit additional circular openings (14). The openings (14) are circular inside the respective electrode and are arranged equidistant in relation to the circle. Anode (1) and cathode (2) exhibit the same number of identical openings in the same geometric arrangement with respect to the axis of symmetry (5). When viewed along the axis of symmetry (5) in the direction of every opening (4) in the anode (2), the result of this design is an opening, located behind it, in the cathode (1). When a voltage is applied to the electrodes, the result is a formation of several plasma lines (15) in the sparking phase of the gas discharge. The plasma lines (15) contract subsequently into a single central radiation-emitting pinched plasma channel (11) on the axis of symmetry (5) owing to the self magnetic field of the flowing electrical current. The radiation is decoupled axially along the axis of symmetry (5). If the electrode facing the x-ray gate is the cathode (1), then it is advantageous to provide a shield (16) between the central opening (4) and the additional openings (14). The shield (16) has the advantage that the sparking that occurs only in the channels of the thin plasma lines (15), but not in the central channel along the axis of symmetry (5), is facilitated. The shield (16) can be omitted, if the electrode facing the x-ray gate (10) is the anode (2), since sparking takes place only on the cathode side. FIG. 5 is a view of an electrode with a central opening (3), which additionally exhibits a ring-shaped opening (17). The ring-shaped opening (17) exhibits a center or an axis of symmetry, which coincides with the axis of symmetry (5) of the electrode configuration. An electrode, which faces the x-ray gate (10) and belongs to this design, requires, as in the embodiment according to FIG. 4, an additional shield (16). 1: cathode 2: anode 3, 4: (main) opening 5: axis of symmetry 6: insulator as the space holder 7: gas-filled space 8: conically designed opening 9a: auxiliary electrode behind the opening of the main electrode 9b: auxiliary electrode between the main electrodes 10: x-ray gate 11: pinched plasma 12: observer 13a, 13b: gas inlet and/or gas outlet opening 14: additional opening in the electrode 15: plasma lines 16: shield 17: ring-shaped opening 19: ultra high vacuum (UHV) area of the device
047560673	abstract	A replacement station includes an old split-pin-assembly (OSPA) removal stand and a new split-pin-assembly (NSPA) installation stand. The removal stand includes a saw and a drill. With the guide tube to which the OSPA is secured in the removal stand, the saw severs each OSPA below the flange which engages the base of the lower counterbore in the lower guide tube (LGT) separating the OSPA into a pin fragment and a second fragment including the flange and the remainder of the split-pin with the nut threaded into it. The second fragment remains secured to the LGT after the sawing operation. The guide tube is rotated so that the drill is coaxial with the shank of the pin of the second fragment. The second fragment is separated into a third fragment including the flange and a fourth fragment including the remainder of the pin and the nut both removable from the LGT. The installation stand has NSPA blades in which the new split pins are mounted. The LGT sans the OSPA's is positioned on the installation stand. The new nuts are mounted and torqued into the split pins with a long-handled runner and a torque tool permitting a measured torque to be applied to the new nut. Then the cups on the nuts are crimped by a long-handled crimping assembly which has fixed crimping jaws that produce the crimping by moving parallel to the wall of the cup.
	summary
	abstract	A modular submersible repairing system includes a working unit having a tool module capable of repairing structures in a reactor. A scanning/pitching module is capable of being selectively connected to or disconnected from the tool module, and is provided with a scanning/pitching shaft for scanning or pitching the tool module. A submersible fan module is capable of being selectively connected to or disconnected from the scanning/pitching module. A first buoyant module keeps an orientation of the tool module. A base unit includes a manipulator module internally provided with an actuator driving mechanism. An adsorbing module is capable of being detachably mounted on the manipulator module and a wall. A second buoyant module keeps the orientation of the manipulator module. The scanning/pitching module and the manipulator module are provided with a submersible connecting device capable of being operated in water for engagement and disengagement.
	summary
048250856	summary	BACKGROUND OF THE INVENTION This invention relates to a radiation image storage panel by use of a stimulable phosphor, more particularly to a radiation image storage panel which can stand uses for a long term. Radiation image such as X-ray image has been frequently used for diagnosis of diseases, etc. For obtaining this X-ray image, the so-called radiation photography has been utilized, in which X-ray which has passed through a subject is irradiated on a phosphor layer (fluorescent screen), thereby forming visible light, and the visible light is irradiated on the film by use of a silver salt and developed similarly as in conventional photographing. However, in recent years, there has been contrived the method in which images are directly taken out from the phosphor layer without use of a film coated with a silver salt. As this method, there is the method in which the radiation passed through a subject is absorbed in a phosphor, then the radiation energy stored by the above absorption in the phosphor is permitted to be radiated as fluorescence by excitation of the phosphor with, for example, light or heat energy, and the fluorescence is detected to form an image. Specifically, for example, U.S. Pat. No. 3,859,527 and Japanese Unexamined Patent Publication No. 12144/1980 disclose radiation image converting method with visible ray or IR-ray as the stimulating light by use of a stimulable phosphor. This method employs a radiation image storage panel having a stimulable phosphor layer formed on a support, and a latent image is formed by irradiating the radiation passed through a subject on the stimulable phosphor layer of the radiation image storage panel and accumulating the radiation energy corresponding to the transmission degree of the radiation at the respective portions of the subject, and thereafter the radiation energies stored at the respective portions are permitted to be radiated to be converted into light by scanning the stimulable phosphor layer with stimulating light, whereby images are obtained by the light signals according to intensity of the light. The final image may be reproduced as hard copy or reproduced on CRT. The radiation image storage panel to be used in the radiation image converting method accumulates radiation image information and thereafter releases the stored energy by scanning of stimulating light, and therefore accumulation of radiation image can be again effected after scanning, thus enabling repeated uses. Accordingly, the above radiation image storage panel should desirably have performances which can stand repeated uses for a long term or for a large number of times without deteriorating the image quality of the radiation image obtained. For this purpose, the stimulable phosphor layer in the above radiation image storage panel is required to be sufficiently protected from physical and chemical stimulations from outside. Particularly, stimulable phosphors are strong in moisture absorption and when the above stimulable phosphor layer absorbs water, barium fluoride bromide type phosphor (e.g. BaFBr:Eu), etc. is decomposed to be lowered in sensitivity to radiation. Also, alkali halide type phosphors (e.g. RbBr:Tl), etc. are fluctuated in sensitivity to radiation by moisture absorption and dehumidication, and also increased or decreased in the fading speed of the radiation energy stored, whereby photographing conditions become unstable and also image quality of the radiation image obtained is deteriorated. For this reason, it has been desired to protect the above stimulable phosphor layer so that no water may be contained therein. In the radiation image storage panel of the prior art, for solving the above problems, there has been employed a protective layer covering the stimulable phosphor layer, on the support of the radiation image storage panel. This protective layer, as described in Japanese Unexamined Patent Publication No. 42500/1984, is formed by direct coating of a coating solution for protective layer on the stimulable phosphor layer, or alternatively by adhering a previously separately formed protective layer onto the stimulable phosphor layer. Further, the present inventors have proposed in Japanese Unexamined Patent Publication No. 176900/1986 and Japanese Patent Application No. 156346/1985 a method for forming a protective layer by applying a coating solution for protective layer, containing a resin material which is cured by polycondensation or crosslinking reaction by irradiation of radiation and/or heating, on the stimulable phosphor layer and then curing the above resin material. For increasing the life of the radiation image storage panel, further improvement, particularly in humidity resistance has been desired, but under the present situation, substantially no investigation has been made concerning moisture prevention except for the method for lowering moisture permeability of the above protective layer. SUMMARY OF THE INVENTION The present invention has been accomplished in view of the state of the art as described above in radiation image storage panel by use of a stimulable phosphor, and an object of the present invention is to provide a radiation image storage panel which remains in a good state for a long term while maintaining dryness of the stimulable phosphor layer. The object of the present invention as mentioned above can be accomplished by a radiation image storage panel, comprising a heat generating body for drying in a radiation image storage panel by using a light stimulable phosphor. As an embodiment of the present invention, the above heat generating body for drying may be contained as assembled in the constituent layer or the support of the radiation image storage panel, or alternatively a layer comprising a heat generating body may be separately provided.
	abstract	A controller for producing a nuclear reactor shutdown system trip signal in response to at least one detector signal. The controller includes a signal conditioning module receiving the at least one detector signal and outputting a measured flux signal. A rate module generates a rate signal from the measured flux signal. A comparator circuit compares the rate signal to a trip setpoint and generates a first trip signal.
062721976	summary	The present invention relates to fuel rod assemblies for nuclear reactors. Fuel rod assemblies, or "elements", for nuclear reactors comprise a plurality of parallel fuel rods or pins which are maintained a set distance apart from each other and mutually parallel by grids at the top, bottom and usually at one or more intermediate positions therebetween in the fuel assembly. A further function of the grids is to maintain the fuel pins apart and thereby to prevent fretting of the fuel pins leading to mechanical damage. Grids employed to the present time are generally constructed by welding together for example many individual components of sheet material to form an array of individual apertures each receiving a fuel pin and having resilient locating means such as "spring fingers" for example formed from the sheet material within the apertures so as to locate the fuel pin as centrally as possible within the aperture. Such grids generally also have vanes integrally formed from the sheet material to induce turbulence in the gas or liquid coolant which flows through the fuel assemblies in a direction generally parallel to the axis of the fuel assembly. The purpose of inducing turbulence in the coolant is to improve the heat extraction from the fuel pins by improved coolant mixing and thus to prevent overheating thereof. Grids such as those described above are generally fabricated from sheet material wherein the plane of the sheet material is generally parallel to the axis of the fuel assembly and comprise substantial quantities of metal in their construction which is detrimental in that the metal is parasitic in absorbing neutrons from the fuel and reducing power output from the reactor. A typical example of such a mixing grid is described in U.S. Pat. No. 5,183 629. In a pressurised water reactor (PWR) for example, the individual fuel pins may be about 4 m in length. The fuel pin comprises an outer tubular sheath known as the "cladding" made from a metal alloy such as "Zircaloy".TM. for example, within which cladding is the fuel per se. Owing to the high temperature reached by the fuel pin in operation, the outer surface of the cladding is subject to corrosion and oxidation where it is in contact with the coolant. The maximum depth of corrosion or thickness of oxide corrosion product of the cladding occurs at about 80% up the length of the pin from the point of entry of the coolant into the fuel pin assembly. The maximum allowable thickness of the oxide layer is a potential life-limiting factor of the fuel pin and consequently of the fuel assembly. Therefore, it is desirable to improve the cooling of the cladding in at least this region so as to reduce the rate of corrosion of the cladding. An improvement of the cooling of the cladding to reduce the rate of corrosion also may have the effect of delaying or providing a greater safety margin prior to the onset of departure from nucleate boiling (DNB) and allowing the fuel assembly to be operated at a higher power level than would otherwise be possible. Nucleate boiling is the most efficient form of heat extraction. DNB occurs where a film of steam occurs at the surface of the fuel pin and heat transfer from the pin to the coolant decreases dramatically resulting in failure of the pin within a very short time. According to a first aspect of the present invention, there is provided a fuel assembly for a nuclear reactor, the fuel assembly including: a plurality of fuel pins extending substantially parallel to the axis of the assembly and to each other; at least two structural grids spaced apart from each other, the grids being in contact with said fuel pins and maintaining said fuel pins substantially mutually parallel and preventing contact therebetween, wherein the fuel assembly further comprises at least one mixing grid situated intermediate said at least two structural grids, the fuel assembly being characterised in that said mixing grid is positioned and fixedly located out of substantial contact with said fuel pins, the mixing grid also having turbulence inducing means to promote turbulence in a coolant flowing through said fuel assembly in use and in that the mixing grid is formed from sheet metal wherein the plane of the metal sheet from which the mixing grid is formed lies in a plane which is transverse to the axis of the fuel pin assembly. The mixing grid of the fuel assembly according to the present invention may alternatively be formed from wire for example and being joined by welding for example at positions where wires cross and also having turbulence inducing means such as vanes for example attached to the wires. However, in a preferred embodiment of the fuel assembly of the present invention, the mixing grid may be formed from sheet metal by for example pressing or stamping wherein the plane of the metal sheet from which the mixing grid is initially formed lies in a plane which is transverse to the axis of the fuel pin assembly. The thickness of the sheet material may be in the range from 0.5 mm to about 1 mm for example. However, the thickness is not considered to be critical and may be chosen so as to be resistant to forces imposed by the coolant flow whilst allowing easy mechanical forming thereof. The mixing grid may be in the form of a framework having an array of apertures of predetermined size and shape, such as square, triangular or hexagonal for example, and through which the fuel pins extend, preferably without making any significant contact with the surrounding framework of each aperture. Where formed from sheet metal as described above by pressing or stamping, turbulence inducing means such as vanes may be integrally formed during such a forming operation and deformed away from a position lying in the sheet plane to a desired angle so as to provide the optimum turbulence inducing effect. Such turbulence inducing means may be formed on an inner edge or edges of each or any apertures as desired consistent with producing the optimum desired turbulence. In view of the many different designs of fuel pin assembly in existence, the optimum configuration and distribution of turbulence inducing means may be determined by experimentation. Some or all of the framework members surrounding each aperture may be twisted about the plane of the sheet so as to form turbulence inducing features per se. Such twisting may also reduce the pressure increase necessary to pump coolant through the fuel pin assembly. The overall outer boundary shape of the mixing grid will correspond to the particular fuel pin assembly into which it is being assembled and may for example be square or hexagonal. The mixing grid of the fuel pin assembly according to the present invention may not extend to and encompass the outer peripheral ring of full pins. The reason for this is that the fuel pins in the outer peripheral ring tend to run cooler than inner fuel pins and thus, the degree of corrosion is less under normal operating conditions. A further advantage of the mixing grid not extending to the outer ring of fuel pins is that the risk of snagging of the fuel assembly during insertion into and removal from the reactor core is lessened. The mixing grid of the fuel pin assembly of the present invention may be held in position within the fuel pin assembly by, for example, so-called thimble tubes in which reactor control rods run; the appropriate grid apertures being sized so as to be located by welding or swaging thereto for example. Alternatively, in a preferred embodiment of the present invention, short stub tubes may be fixed to the mixing grid by welding, for example, at positions which correspond to some or all of the thimble tubes such that the short tubes fit over the thimble tubes and are in turn fixed, by crimping or welding for example, to the thimble tubes. Determination of the optimum position or positions of mixing grids within the fuel pin assembly may be determined by experimentation and will vary according to the fuel pin assembly design, the type of coolant and/or the type of reactor in question. Sufficient mixing grids may be employed such that the maximum temperature of the hottest fuel pin or pins are reduced to a level where cladding corrosion does not restrict the burn-up life of the fuel. Improved mixing of the flowing coolant by inducing turbulence therein appears to occur in known fuel pin assemblies in the regions immediately preceding and immediately following a structural grid. Therefore, it might be thought that the inclusion of known structural grids in additional positions within the fuel assembly would be advantageous in promoting extra turbulence to improve cooling and heat extraction in desired locations so as to reduce corrosion/oxidation rate. However, this solution has several significant disadvantages. Firstly, prior art structural grids are extremely expensive to produce owing to their complex structure. Secondly, known structural grids contain substantial quantities of metal which absorbs neutrons causing significant parasitic power loss. Thirdly, additional structural grids provide additional locations where grid-to-rod fretting damage can occur. The mixing grid of the fuel pin assembly of the present invention on the other hand is simple and cheap to make as it may be formed from a single stamping or pressing of an initially flat metal sheet; it contains only a relatively small quantity of metal so that parasitic losses due to neutron capture are minimal; and, the fuel pins of the preferred embodiment do not touch the mixing grid and therefore there can be no fretting damage to the fuel pin caused by the mixing grid. According to a second aspect of the present invention, there is provided a mixing grid for a fuel pin assembly according to the first aspect.
	summary
	claims	1. An extreme ultraviolet light generation apparatus configured to generate extreme ultraviolet light by irradiating a target with a pulse laser beam outputted from a laser apparatus to generate plasma, the extreme ultraviolet light generation apparatus comprising:a chamber;a target supply device configured to supply a target to a plasma generation region inside the chamber;a target sensor located between the target supply device and the plasma generation region and configured to detect the target passing through a detection region;a shield cover disposed between the detection region and the target supply device, having a through-hole that allows the target to pass through, and configured to reduce pressure waves that reach the target supply device from the plasma generation region;a heat shield disposed between the plasma generation region and the shield cover, structured to accommodate the plasma generation region, having a through hole that allows the target to pass through, and configured to reduce heat conducted to the chamber from the plasma generation region; anda first damper between the heat shield and an inner wall of the chamber. 2. The extreme ultraviolet light generation apparatus according to claim 1, wherein the shield cover is fixed to the chamber with a second damper interposed between the shield cover and the chamber. 3. The extreme ultraviolet light generation apparatus according to claim 2, further comprising:a stage configured to move the target supply device; anda supporter fixed to the chamber and configured to support the stage. 4. The extreme ultraviolet light generation apparatus according to claim 1, further comprising a gas introduction device disposed on the opposite side of the plasma generation region across the shield cover and configured to supply purge gas to a space between the target supply device and the shield cover. 5. The extreme ultraviolet light generation apparatus according to claim 1, further comprising a plasma shield disposed between the shield cover and the target supply device, having an opening that allows the target to pass through, and configured to reduce particles that reach the target supply device from the plasma generation region. 6. The extreme ultraviolet light generation apparatus according to claim 1, further comprising a pressure wave attenuator disposed on the shield cover to face the plasma generation region. 7. The extreme ultraviolet light generation apparatus according to claim 1, wherein the shield cover is fixed to the chamber with a plurality of second dampers interposed between the shield cover and the chamber. 8. The extreme ultraviolet light generation apparatus according to claim 7, wherein each of the plurality of second dampers is one of a spring, a rubber cushion, and a bellows. 9. The extreme ultraviolet light generation apparatus according to claim 3, wherein the shield cover is fixed to the stage. 10. The extreme ultraviolet light generation apparatus according to claim 1, further comprising:a stage configured to move the target supply device; anda supporter fixed to the chamber and configured to support the stage,wherein the shield cover is fixed to the stage. 11. The extreme ultraviolet light generation apparatus according to claim 1, wherein the shield cover is made of a metal. 12. The extreme ultraviolet light generation apparatus according to claim 4, wherein the gas includes hydrogen. 13. The extreme ultraviolet light generation apparatus according to claim 5, wherein the opening of the plasma shield is smaller than the through-hole of the shield cover. 14. The extreme ultraviolet light generation apparatus according to claim 5, further comprising:a stage configured to move the target supply device; anda supporter fixed to the chamber and configured to support the stage,wherein the plasma shield is fixed to the stage and moved by the stage with the target supply device. 15. The extreme ultraviolet light generation apparatus according to claim 6, wherein the pressure wave attenuator is made of a porous material. 16. The extreme ultraviolet light generation apparatus according to claim 15, wherein the porous material includes porous ceramics or a foam metal. 17. The extreme ultraviolet light generation apparatus according to claim 1, wherein the through hole of the heat shield is larger than the through-hole of the shield cover.
050911465	description	IN THE SPECIFICATIONS Referring to FIG. 1, a fuel bundle B utilizing this invention is illustrated. The fuel bundle is, for the most part, conventional. The reader will note that the preferred embodiment of the invention as set forth in FIG. 1 does not include water rods. As will hereinafter more fully be developed, the presence of the steam vent tubes of this invention may well obviate the need for such water rods. The fuel bundle here illustrated includes full length fuel rods 20 and part length fuel rods 22. Full length fuel rods 20 are conventional and extend the full distance between lower tie plate 14 to upper tie plate 16. The reader will understand that the channel C has been broken away so that the fuel rods are exposed. Part length rods 22 are also present. These part length rods extend from lower tie plate 14 and terminate short of upper tie plate 16. Spacers are also utilized. Typically, as here shown, seven such spacers are evenly placed throughout the fuel bundle. Part length rods 22 are here shown terminating just above spacer 5. Thereafter, at spacer 6 and 7, a steam vent volume is defined overlying the end of the part length rods. It is into this steam vent volumes that the steam vent tubes T1-T4 of this invention are placed. The reader will understand that the length of fuel rod used here is exemplary; lengths of fuel rods other than those specifically shown may be used. Referring to FIG. 2, this type of steam vent tubes placed within the fuel bundle B of FIG. 1 are illustrated. Specifically, paired full length rods 20 are shown sectioned from an interior portion of the bundle extending upwardly on either side of a part length rod 22. Part length rod 22 terminates at spacer S5 just above the spacer at end 40. Overlying, or connected to end 40 of the part length rod is steam vent tube T1 having a deflector 19 which is here shown conical in shape. Deflector 19 is separated a small interval from steam vent tube T1 for the purpose of deflecting water off the end of the rod and permitting the preferential entry of steam into vent tube T1. Tube T1 includes a lower opening 42 for receiving steam off the end of part length rod 22 at end 40. The tube extends upwardly and through the upper tie plate 16 at a discharge end 44 for venting steam through the upper tie plate. Suspension of the steam vent tube occurs from upper tie plate 16 and spacers S6 and S7 (see FIG. 1). Optimally, and adjacent the end 40 of partial length rod 22 in the steam vent tube, there can be provided openings 44, 46. These openings can have functions for either ejecting water from the interior of the steam vent tube T1, or for admitting steam. The function of these openings will hereinafter be described with respect to FIGS. 7 and 8. Referring to FIG. 3, an alternate embodiment of the steam vent tubes is illustrated at T5. A partial length rod 22 is again shown between full length rods 20 terminating at end 40. Overlying the part length rod 22, there is provided a steam vent tube 25 and deflector 19. Comparing this view with that shown in FIG. 2, it can be seen that the diameter of the tube T5 exceeds the diameter illustrated of both the rods 20, full length rods 20, and the part length rods 22. All other constructions remain, including lower opening 42, upper opening 44, and vents 44,46. Referring to FIG. 4, an additional steam vent tube T6 is illustrated. Tube T6 is shown at its lower end only between lower spacer S5 and upper spacer S6. As can be seen in the view of FIG. 4, four part length rods 22A, 22B, 22C and 22D are placed inside in a side-by-side array. Rods all terminate at an upper end 40 which end 40 is clustered interior of the fuel bundle. Thus, the volume overlying the ends of the part length rods 40 and the upper tie plate constitutes an interval which would normally be occupied by four full length rods 20. A steam trapping entry is provided by a first complete cone 50 and a second cone truncated at the apex, this second cone being designated 52. Portions of the complete cone 50 are broken away to expose the truncated apex 54. As before, apertures 44,46 interrupt and manifold the sidewalls of the steam vent tube T6. An explanation of the entry of steam and the rejection of water at the respective cones 50,52 is instructive. As is well known, in a two-phase liquid vapor mixture, the liquid occupies a higher density. Therefore, upon impact with lower cone 50, liquid will typically continue along the outside of the tube T6 (see the schematically illustrated liquid at vector 60). The low density steam is another matter. Typically, the steam will find its way around and into the truncated apex 54 of truncated cone 52 (see schematic vectors 62). Stated in ordinary terms, the steam has a density which will admit of its following circuitous flow paths. Once the steam is interior of the steam vent tube T6, upward flow will continue. Thus far, all steam vent tubes illustrated have been of circular section. Referring to FIG. 5, a square section T7 steam vent tube is illustrated. Referring to FIG. 5, a plurality of full length rods 20 surrounds a cluster of nine partial length rods 22. Partial length rods 22 all terminate at upper ends 40. Since the rods 22 are in a 3.times.3 array, it will be understood that overlying the ends 40 of the part length rods there exists a steam vent volume that may be suitably occupied by a square sectioned steam vent tube T7. Steam vent tube T7 has a generally conical bottom 70 flaring to a square sectioned tube structure 72. As before, tube structure 72 continues upwardly through the upper tie plate, it being realized that the top portion of the tube T7 is not illustrated. As before, apertures 44,46 are present. Referring to FIG. 6A, a steam vent tube placed within a generally conical void within a fuel bundle is shown. A plan view of the steam vent tube T8 is illustrated in FIG. 6B. Referring to FIG. 6B, a 9.times.9 array of full length rods is illustrated. This 9.times.9 array has 21 part length rods 22 terminating underlying the steam vent tube T8. Referring to FIG. 6A, it can be seen that the central length rod 22 terminates at a first elevation 91. Second part length rods 22 terminate at second elevations 92. Finally, third groups of path length rods 22 terminate at third elevations 93. The rods are placed in a stepped configuration similar to that illustrated in Ueda, Japanese Patent Showa 52-50489 so as to define from lower spacer S5 to upper tie plate 16, a generally conical volume. This volume is filled with a step tapered tube T8. Tube T8 includes a flare portion 100 at the upper end of short partial length rod 22. Thereafter, a cylinder 102 connected by truncated cone 104, connects to cylinder 106. A second truncated cone 108 connects to cylinder 110. Cylinder 110 extends upwardly to and possibly through tie plate 16. As before, alternating openings 46,48 are shown utilized. Referring to FIG. 7, a vent 46 is illustrated which vent 46 in the side of a vent tube T permits the preferential entry of vapor along an illustrated path 120. Aperture 46 includes an upper opening 122 and is disposed outwardly from the linear wall 124. As can be seen, vapor with its low density can follow the circuitous path 120. Water with its higher density will pass by aperture 122 as illustrated in vector 126. It will be realized that the aperture shown in FIG. 7 is shown in a planar wall. This aperture can just as easily be adapted to circular walls. Referring to FIG. 8, a vent 48 is illustrated which vent 48 is for the ejection of water interior of the wall 124. Specifically, water will normally flow against the wall. Since aperture 132 of opening 48 is downwardly disposed, water tracking along wall 124 will be ejected from the interior of the steam vent tube T. It will be realized that the placement of the respective apertures 46,48 and their respective dimensions will be a function of the size of the steam vent tube, the total volume of vapor to flow within the tube as well as the total volume of water to be ejected from the tube. Thus, the designer will place these apertures and dimension them in accordance with the design parameters of the fuel bundle involved. It will be realized that I have shown my preferred embodiment without a water rod. Those having skill in the art will understand that a water rod can be added. Further, I have shown the steam vent tubes of my invention fastened to the spacers and tie plates. The steam vent tube can as well be fastened to the end of the part length rod.
	description	This application is a divisional of U.S. patent application Ser. No. 10/014,976 filed Dec. 11, 2001, entitled “Molten Metal Reactor Utilizing Molten Metal Flow for Feed Material and Reaction Product Entrapment,” now U.S. Pat. No. 6,717,026 B2, which claimed priority from U.S. provisional patent application Ser. No. 60/271,825 filed Feb. 27, 2001, entitled “Molten Metal Reactor Utilizing Molten Metal Flow for Feed Material and Reaction Product Entrapment.” The Applicant claims priority from U.S. patent application Ser. No. 10/014,979 under 35 U.S.C. §120, and claims priority from provisional application No. 60/271,825 under 35 U.S.C. §119(e). The entire content of each of these applications is incorporated herein by this reference. This invention relates to molten metal reactors for treating waste materials and soils contaminated with waste materials. More particularly, the invention relates to a molten metal reactor having an improved arrangement for entraining or entrapping feed materials with a molten reactant metal to effect the desired chemical reduction of the feed material. The invention encompasses a molten metal reactor apparatus, a structure for introducing a feed material into such a reactor, a method for treating waste material with a molten metal, and a method for introducing a feed material into a molten metal reactor. Molten metal reactors utilize a molten reactant metal to chemically react with a feed material in order to reduce the feed material to relatively innocuous compounds and chemical elements. For example, U.S. Pat. No. 5,000,101 to Wagner discloses a molten metal reactor for treating chlorinated hydrocarbons and other dangerous organic chemicals to produce carbon, metal salts, and gases such as nitrogen and hydrogen. U.S. Pat. No. 5,271,341 to Wagner discloses a molten metal reactor for treating boxed biomedical wastes which may include hazardous biological wastes mixed with other materials and metals. The disclosed molten reactant metal chemically reduces biological materials and other organic materials in this waste to carbon, metal salts and elemental gasses. Metals such as stainless steel “sharps” in the waste dissolve or melt into the reactant metal. A consistent issue with molten metal reactors is providing the necessary contact between the material to be treated or reacted, that is, the “feed material,” and the molten reactant metal. U.S. Pat. No. 5,271,341 to Wagner discloses submerging the boxed biomedical wastes in the reactant metal bath with a submerging or plunger structure to provide the desired contact between the waste material and the molten reactant metal. Although the submerging structure works well with certain types of waste materials, such structures are not well suited for submerging other types of materials. In particular, plunger structures are not well suited for use in relatively high-volume waste treatment applications in which relatively large quantities of loose or bulk feed materials, such as contaminated soils, for example, must be processed. A molten metal reactor according to the present invention quickly entrains a feed material in the molten reactant metal and provides the necessary contact between the molten reactant metal and the feed material to effect the desired chemical reduction of the feed material. The quick entrainment of feed material in the molten reactant metal is accomplished with a unique feed structure in which the feed material is added to the reactant metal and then quickly transferred into a treatment chamber together with the molten reactant metal and any initial reaction products. A majority of the desired reactions occur in the treatment chamber. Reaction products and unspent reactant metal are preferably directed from the treatment chamber to an output chamber where reaction products are removed from the reactor. Unspent reactant metal is then preferably transferred to a heating chamber where it is reheated for recycling through the system. According to the invention, the feed structure associated with the reactor introduces feed material into the molten reactant metal so that a flow of molten reactant metal immediately carries substantially all of the feed material and any initial reaction products into the treatment chamber. The feed material and reaction products are then trapped in the treatment chamber preferably by means of a suitable gravity trap structure. This combination of substantially immediate introduction into the treatment chamber and trapping in the treatment chamber helps ensure that the feed material and any intermediate reaction products have sufficient contact with the molten reactant metal to provide the desired chemical reactions, that is, the substantially complete chemical reduction of the feed material. The desired contact with the reactant metal is enhanced according to the invention by inducing a swirling or vortex flow in the molten reactant metal in a feed chamber in which the feed material first makes contact with the molten reactant metal. This swirling flow may be produced in any suitable fashion, including by directing the molten metal into the feed chamber in an off center position, by driving the molten metal in the feed chamber with an impeller, or both. Also, a bowl-shaped feed chamber helps facilitate the desired swirling flow. In order to carry the feed material and any initial reaction products quickly into the treatment chamber in the flow of molten reactant metal, the feed material preferably comes into contact with the molten reactant metal in an area adjacent to an inlet to the treatment chamber. An area “adjacent” to the treatment chamber inlet means the area of the surface of the molten reactant metal in the feed chamber generally nearest to the inlet of the treatment chamber. In the form of the invention in which a swirling flow is induced in the feed chamber, the feed material drops into the molten reactant metal in a central area of the feed chamber, at the center of the swirling flow or vortex, and directly above an outlet from the feed chamber/inlet to the treatment chamber. The feed chamber includes an outlet that at least borders the treatment chamber inlet and more preferably comprises a common opening with the treatment chamber inlet. By “bordering” the treatment chamber inlet it is meant that the feed chamber outlet is in the immediate vicinity of the treatment chamber inlet so that there is only a small distance between any point of the feed chamber outlet and any point of the treatment chamber inlet. The feed material may include substantially any material or mixture of materials suitable for treatment in a molten metal reactor. These materials include hydrocarbons and halogenated hydrocarbons, low and high level radioactive materials, and any other materials that may be chemically reduced in a molten reactant metal such as aluminum, magnesium, or combinations of these metals together with other metals. The invention is particularly suited to treating soils and other bulk solids which have been contaminated with hydrocarbons, halogenated hydrocarbons, other chemically reducible materials, radioactive materials, and metals. As used in this disclosure and the accompanying claims a “feed material” may comprise any of the above-described materials or combinations of these materials. It will be appreciated by those skilled in the art of molten reactors that the chemical reduction reactions produced by contact with a molten reactant metal may not immediately reduce a given constituent compound included in a feed material. Rather, many chemical compounds suitable for treatment with a molten reactant metal may initially react in or with the metal to produce intermediate reaction products. These intermediate reaction products are then further reduced by reaction in or with the molten reactant metal. The reactions continue in the molten reactant metal until the reduction reactions are substantially complete, leaving only final reaction products. Metals in the feed material compounds are generally reduced to their elemental state, carbon is reduced to its elemental state and goes to a gaseous state at the temperature of the molten reactant metal, halogens form salts with either metals from the molten reactant metal bath or with metals contained in the feed material itself. Nitrogen and hydrogen liberated from the reacted compounds escape from the molten metal bath as gases. Minerals included in soil generally remain unreacted in the molten reactant metal depending upon the makeup of the molten reactant metal bath and its temperature, but may go to a liquid state at the temperature of the molten metal bath. As used in this disclosure and the accompanying claims, the term “reaction product” is used to refer to any reaction product produced by treatment of the feed material with the molten reactant metal, whether the reaction product is an initial reaction product subject to further reactions in the molten metal or a final reaction product that is chemically stable in the molten reactant metal. The term “reaction product” also refers to materials such as quartz that do not chemically react with the molten reactant metal but may be contained in soil contaminated with materials that do react in the molten reactant metal. Thus, the term “reaction product” means generally any material that results from any reaction of a feed material occurring in the molten reactant metal. The above-described advantages and features of the invention, along with other advantages and features, will be apparent from the following description of the preferred embodiments, considered along with the accompanying drawings. Referring particularly to FIGS. 1 and 2, a molten metal reactor 10 embodying the principles of the invention includes essentially four chambers including a bowl-shaped vortex or feed chamber 11, a treatment chamber 12, an output chamber 14, and a heating chamber 15. Each of these chambers is adapted to contain a molten reactant metal indicated by the reference numeral 16. The level of molten reactant metal 16 in feed chamber 11, output chamber 14 and heating chamber 15 is indicated by the dashed line in the respective chamber. Molten reactant metal 16 is heated to the desired temperature in heating chamber 15 and then transferred to feed chamber 11. From feed chamber 11, molten reactant metal 16 flows rapidly into treatment chamber 12 and then exits the treatment chamber into output chamber 14. From output chamber 14, molten reactant metal 16 returns to heating chamber 15 for reheating and recycling through the reactor 10. Reaction products are removed from reactor 10 through output chamber 14. According to the invention, the flow of molten reactant metal from feed chamber 11 to treatment chamber 12 carries feed materials to be treated into the treatment chamber along with substantially all reaction products liberated from the feed material on initial contact with the molten reactant metal. Treatment chamber 12 provides sufficient residence time to completely react substantially all constituents in the feed material. FIG. 1 in particular indicates that molten metal reactor 10 includes numerous components that contain or come in contact with molten reactant metal 16. All components that do come in contact with the molten reactant metal are either formed from a material which is resistant to damage from the reactant metal or coated with such a protective material. For example, the system of chambers 11, 12, 14, and 15 may be cast from a refractory material or may be formed from a base material which is then coated with a suitable refractory or other chemically resistant material. The particular reactant metal utilized in reactor 10 will depend upon the constituents in the feed material which must be destroyed or removed from non-hazardous constituents of the feed material. A preferred reactant metal suitable for use in treating many types of chemicals comprises an alloy of aluminum as disclosed in U.S. Pat. No. 5,000,101 to Wagner, the entire content of which is hereby incorporated in this disclosure. However, it will be appreciated that the makeup of reactant metal 16 may be varied to suit a particular feed material to be treated in reactor 10 and is not limited to aluminum or aluminum alloys. Also, the temperature of reactant metal 16 may be varied to suit the particular feed material to be treated. Reactor 10 is well suited for treating a number of feed materials, including particularly contaminated soils. The soils may be contaminated with halogenated hydrocarbons or other organic compounds, metals, and low-level radioactive materials. Organic compounds are reduced to liberate carbon and hydrogen. Halogens included in organic compounds generally react with elements of the reactant metal to form metal salts, while other materials dissolve or melt into the molten reactant metal or release from the reactant metal as a gas. Many radioactive materials dissolve or melt into the reactant metal 16 where the radioactive isotopes can be concentrated to the desired level together with radioactive emission absorbing elements. Molten reactant metal and absorbing metal containing the radioactive isotopes may then be drawn off to form ingots that can safely store the radioactive isotopes. In addition to the chamber arrangement shown in FIGS. 1 and 2, the preferred reactor 10 includes molten metal pumps 20 and 21 shown in FIG. 2, and a heater arrangement 22 associated with at least heating chamber 15. A feed arrangement 24 is associated with feed chamber 11 for transferring feed materials into the system. Also, the illustrated reactor 10 includes a reaction product removal arrangement associated with output chamber 14. The reaction product removal arrangement is shown generally at reference numeral 25. Referring to both FIGS. 1 and 2, feed chamber 11 includes an outlet 28 generally at the bottom of the feed chamber. Feed arrangement 24 is located preferably immediately over or above outlet 28. Molten reactant metal 16 is supplied into feed chamber 11 through an inlet 29. As shown best in FIG. 2, the preferred form of the invention has inlet 29 positioned off-center from a center vertical axis of feed chamber 11 so that the flow of reactant material into the chamber helps induce a swirling or vortex flow in the feed chamber as will be described further below. Referring still to FIG. 2, reactant metal 16 collects in a supply chamber 31 prior to flowing into feed chamber 11. This flow may be continuous or may be on a batch basis. Where reactant metal is released into feed chamber 11 in batches, a suitable valve (not shown) may be associated with inlet 29. The valve may be closed to allow reactant metal 16 to collect in supply chamber 31 then may be opened to suddenly release the reactant metal into feed chamber 11. It will be appreciated that it is possible to eliminate pump 21 and instead use a moveable crucible or vessel to periodically lift molten reactant metal from heating chamber 15 and pour the molten metal into supply chamber 31. This moveable crucible form of the invention may be used to introduce a rapid flow of molten reactant metal into supply chamber 31 and then into feed chamber 11. The preferred form of the invention produces a vortex or swirling flow in the reactant metal 16 contained in feed chamber 11 as the molten metal flows rapidly into the feed chamber and then into treatment chamber 12. This swirling or vortex flow is indicated by the arrows 32 in FIG. 2. In the form of the invention shown in FIGS. 1 and 2, the off-center molten metal inlet 29, bowl-shaped feed chamber 11, and flow rate of molten reactant metal all combine to provide a vortex inducing arrangement. The swirling flow of reactant metal 16 in feed chamber 11 provides a good mixing action to rapidly incorporate or ingest the feed material into the reactant metal. It will be appreciated that the swirling reactant metal or vortex flow of molten reactant metal in feed chamber 11, is not necessary to the present invention but is helpful to the operation of the present invention. Sufficient reactant metal 16 flow rates may be produced to provide the desired waste material entrainment without inducing a vortex in the reactant metal as it flows from feed chamber 11 into treatment chamber 12. For example, molten metal pump 21 may pump molten reactant metal into feed chamber 11 at a rate on the order of fifteen thousand (15,000) pounds per minute to produce high molten metal flow velocities from an appropriately sized feed chamber outlet to an appropriately sized treatment chamber inlet. Feed arrangement 24 is adapted to transfer feed materials into reactor 10 while minimizing the amount of oxygen entering the reactor. Feed arrangement 24 includes an elongated chute 35 which is preferably centered within feed chamber 11 to drop feed material into the center of vortex or swirling flow, immediately above or adjacent to outlet 28 from the feed chamber to treatment chamber 12. The bottom end of feed chute 35 may be referred to as a feed material inlet into feed chamber 11. Feed chute 35 includes a purge chamber 36 defined between an upper dump gate 38 and a lower dump gate 39. A purge gas, in this case flue gas from heater arrangement 22 is circulated to the purge chamber through conduit 40 to purge chamber 36 of oxygen. In operation, lower dump gate 39 is held in a closed position sealing a bottom of purge chamber 36 while upper dump gate 38 is held open and feed material is loaded into the purge chamber. Once purge chamber 36 is loaded with feed material, upper dump gate 38 is closed and purge gas is circulated through the chamber to purge the chamber of oxygen. After the chamber is sufficiently purged, lower dump gate 39 is opened so that the feed material in chamber 36 drops into the molten reactant metal in feed chamber 11. The opening of lower dump gate 39 to drop feed material into feed chamber 11 may be coordinated with the release of molten reactant metal 16 into the feed chamber to create the desired swirling flow and suction effect as the molten reactant metal flows out of the feed chamber and into treatment chamber 12. An additional sealing conduit 42 may be associated with the feed chute 35 to isolate the area of feed chamber 11 generally above or adjacent to the feed chamber outlet 28. Additional sealing conduit 42 may be used to ensure that the feed material and reaction products flow along with the reactant metal 16 into treatment chamber 12. It will also be noted that the top of feed chamber 11 above the level of reactant metal 16 is sealed to the atmosphere so that any reaction products that may remain in feed chamber 11 are not released to the atmosphere. Treatment chamber 12 comprises a tube or conduit extending from the feed chamber outlet opening 28 to output chamber 14. The preferred treatment chamber 12 also includes a gravity trap 44 having a U-shaped segment that helps prevent gases from flowing back into feed chamber 11. Treatment chamber 12 is long enough to provide sufficient residence time, considering the reactant metal flow rate through the tube, to effect a substantially complete reaction of materials that are to be destroyed in the molten metal reactor. Residence times should be approximately three (3) minutes to effect the desired treatment for most feed materials. The flow velocity in treatment chamber 12 may be eight (8) feet per minute. In order to help maintain the reactant metal 16 at a desired treatment temperature in treatment chamber 12, the treatment chamber may be located immediately adjacent to heating chamber 15 so that heat from the heating chamber is transferred to material within the treatment chamber. Also, although not shown in the drawing, a separate heating system may be associated with the treatment chamber 12 for maintaining the temperature of the molten metal at a desired temperature within the treatment chamber. Any suitable heating system may be used with treatment chamber 12 including an induction heating system using one or more electromagnetic field induction coils positioned adjacent to the treatment chamber. Although a molten reactant metal level is shown by a dashed line in FIG. 1 for chambers 11, 14 and 15, FIG. 1 does not show a molten reactant metal level in treatment chamber 12. This should not be taken to imply that there will be no gas phase in treatment chamber 12. For many feed materials, a distinct gas phase of reaction products will emerge in the top of treatment chamber 12. However, these reaction products will be held in close proximity to the surface of the molten reactant metal 16 in position to facilitate further reaction of the reaction product if not fully reduced. Gaseous reaction products will also bubble up through molten reactant metal in the output chamber 14 to allow any further reactions possible between the reaction products and molten reactant metal. A molten metal reactor within the scope of the present invention may include a feed chamber having an outlet that is separate and distinct from an inlet to the treatment chamber in the reactor. However, in the preferred form of the invention shown in FIGS. 1 and 2, feed chamber outlet 28 is common with the inlet to treatment chamber 12, that is, the feed chamber outlet and treatment chamber inlet comprise the same opening. The outlet from the feed chamber according to the invention at least borders the inlet to the treatment chamber. This proximity between feed chamber outlet 28 and the inlet to the treatment chamber combined with the proximity between the point at which the feed material makes initial contact with the molten reactant metal 16 and the rapid flow of molten reactant metal into treatment chamber 12 ensures that the feed material and even any initial reaction products are carried into the treatment chamber where the desired reactions may proceed to completion. The residence time for feed materials in the feed chamber after initial contact with the molten reactant metal should be on the order of ten (10) seconds or less. Residence times in this range will be considered insignificant residence times within the scope of the following claims. Output chamber 14 is connected to receive material exiting an outlet 45 of treatment chamber 12. The material which flows into outlet chamber 14 includes molten reactant metal 16 remaining after the desired reactions with the feed material and reaction products from the reaction of the feed material with the reactant metal. The reaction products may include molten or gaseous metal salts, gaseous carbon, unreacted solids such as clay particles included in the feed material, metals from the feed material that have dissolved or melted into the reactant metal, and other gases liberated in the various reactions between the molten reactant metal 16 and the feed material. These other gasses will commonly include primarily nitrogen and hydrogen. The reaction product removal arrangement 25 associated with output chamber 14 includes a skimming system shown generally at reference numeral 49 and a gas and particulate removal system shown generally at reference numeral 50. A tapping system including tapping line 51 with a suitable valve may also be connected to output chamber 14 for removing heavy molten material or dissolved material that may segregate to the bottom of the output chamber. Gas and particulate removal system 50 includes a collection hood 54 at the top of output chamber 14 and an outlet conduit 55. This outlet conduit 55 preferably leads to particulate control equipment (PCE) 56 such as a bag house or an aqueous scrubber that removes particulates included in, or forming from, the gases exiting output chamber 14 through conduit 55. Flue gas from the heater arrangement 22 may be directed into collection hood 54 through conduit 57 to enhance the flow of gases and particulates out of the system through conduit 55. The purge gas from purge chamber 36 may also be directed into conduit 55 to exit the system through particulate control equipment 56. Skimming system 49 is located at the top of output chamber 14 for removing solids and light molten materials that segregate to the top of the reactant metal 16 in the output chamber. The illustrated skimming system 49 includes an auger 58 which is rotated by a suitable drive device 59 to skim material floating at the surface of the molten reactant metal 16 to the right in FIG. 1 toward an outlet chute 60. Outlet chute 60 leads to an airlock chamber 61 defined between an upper airlock gate 62 and a lower air lock gate 63. In operation, lower gate 63 is closed and upper gate is held open while auger 59 skims material through outlet chute 60 and into the airlock chamber 61 above the lower gate. After an appropriate amount of skimmed material has collected in airlock chamber 61, upper gate 62 is closed and lower gate 63 is opened to allow material collected in the air lock chamber to drop into a collection vessel 64. Positive pressure maintained in the collection hood 54 provided by the heater flue gas helps ensure significant amounts of oxygen does not flow into the reactor 10 as solid material and light molten material is removed through airlock chamber 61. One or more deflectors such as deflector 66 may be associated with output chamber 14 to deflect reaction products to the desired locations within the outlet chamber and ensure that materials do not inadvertently enter heating chamber 15. Deflectors may also be used in outlet chamber to enhance contact with the molten reactant metal and help ensure that the desired reactions proceed to completion. That is, deflectors in output chamber 14 may be arranged to cause relatively light reaction products to follow a tortuous path through the molten reactant metal in output chamber 14 before reaching the surface of the molten reactant metal. Heating chamber 15 comprises a chamber having a lower portion adapted to contain a volume of reactant metal and an upper area which is isolated from the feed chamber 11 and output chamber 14. This isolation is required in the illustrated form of the invention to accommodate the gas fired burners 70 that make up heating arrangement 22 used to heat the reactant metal 16 within heating chamber 15. Exhaust gas from burners 70 exits the upper part of the heating chamber through flue gas stack 71. A portion of this flue gas is directed to purge chamber 36 and to collection hood 54 as described above. Although gas fired burners are shown in the illustrated form of the invention, other heating systems such as an induction heating system for example, may be employed to heat the reactant metal 16 in heating chamber 15. Of course, when electromagnetic induction heating is used to heat reactant metal 16, a separate purge gas must be used in connection with feed purge chamber 36 and collection hood 54 since the flue gas would not be present. Proper flow and circulation of molten reactant metal 16 in reactor 10 is important to the proper operation of the reactor. In particular, the flow of molten reactant metal 16 from feed chamber 11 to treatment chamber 12 should be at a sufficient rate to entrain or entrap feed material and substantially any initial reaction products, and cause these materials to be carried or swept into the treatment chamber and ultimately into output chamber 14. Minimum flow velocities of molten reactant metal into treatment chamber 14 will depend upon the fluid properties of the particular molten reactant metal and the specific gravity and other properties of the feed material. The desired flow rates may be produced using pumps for moving the molten reactant metal. FIG. 2 shows two molten metal pumps in the preferred form of the invention. Pump 20 pumps molten reactant metal 16 from output chamber 14 to heating chamber 15. Pump 21 pumps the heated or reheated molten reactant metal 16 from heating chamber 15 to feed chamber 11, in the illustrated case through supply chamber 31. It will be noted from FIG. 1 that the level of molten reactant metal 16 in feed chamber 11 may be higher than in heating chamber 15 and output chamber 14. In this arrangement the molten reactant metal 16 provides a hydrostatic head which helps cause the molten metal to flow from feed chamber 11 into treatment chamber 12 and then into output chamber 14. However, the desired flow rates and vortex or swirling flow may be produced without the higher molten reactant metal level in feed chamber 11. Also, it will be appreciated that the desired flow rates of molten reactant metal into treatment chamber 14 may be produced without the illustrated molten metal pumps. As discussed above, in alternative arrangements a portion of the molten reactant metal from heating chamber 15 may be lifted in a suitable vessel and dumped into feed chamber 11 (or into supply chamber 31) in order to produce the desired flow of reactant metal 16 through the feed chamber and into treatment chamber 12. Alternatively, molten reactant metal 16 may be collected in supply chamber 31 and released abruptly to flush feed material from feed chamber 11 into treatment chamber 12. FIG. 3 shows an alternate vortex inducing arrangement according to the invention. This alternative form of the invention includes the same preferably bowl-shaped feed chamber 11, treatment chamber 12, and heating chamber 15 included in the embodiment shown in FIGS. 1 and 2. FIG. 3 is broken to omit other portions of the reactor that are identical to those set out in FIGS. 1 and 2, and do not involve the alternate vortex inducing arrangement. In the form of the invention shown in FIG. 3, an impeller 80 is included to help induce the desired swirling or vortex flow of molten reactant metal in feed chamber 11. Impeller 80 may comprise any suitable impeller device suitable for use in a molten reactant metal. U.S. Pat. No. 4,930,986 shows a suitable impeller, and is incorporated herein by this reference. The type of impeller shown in this patent also forces feed material and molten reactant metal downwardly in feed chamber 11 toward the outlet to treatment chamber 12. Impeller 80 is driven by drive shaft 81 about a vertical axis V aligned generally in the center of feed chamber 11. A suitable motor and drive device 82 rotates drive shaft 81. Drive shaft 81 preferably extends though a protective conduit 84. Conduit 84 helps protect drive shaft 81 from feed material entering the reactor through feed arrangement 85. Because the center portion of feed chamber 11 is occupied by the impeller 80 and supporting structure, feed arrangement 85 differs from feed arrangement 24 shown in FIG. 1. Feed arrangement 85 includes an elongated feed chute 86 that extends at an acute angle with respect to axis V. Feed chute 86 includes upper and lower dump gates 87 and 88 respectively to define a purge chamber 89 similar to purge chamber 36 shown in FIG. 1. The dump gates purge line 90 and purge chamber all operate similarly to the corresponding elements shown in FIG. 1 and thus will not be described further here. An outlet end 91 of feed chute 86 represents a feed material inlet to feed chamber 11 and terminates in a sealing or confinement conduit 94 similar to the sealing conduit 42 shown in FIG. 1 and functions similarly to help confine feed material just to the volume of molten reactant metal 16 immediately above the feed chamber outlet 28. The flow rate of molten reactant metal 16 into and out of feed chamber 11 may be the same as in the embodiment described with reference to FIGS. 1 and 2. Thus, the flow of molten metal 16 through inlet 29 and the bowl shape of feed chamber 11 may be sufficient to induce some swirling flow in the feed chamber around axis V. Impeller 80 enhances the swirling flow and further helps to submerge and entrain feed material in the molten reactant metal 16 so that the feed material may be quickly carried in the flow of molten metal into treatment chamber 12. FIG. 4 shows yet another alternate feed arrangement for a reactor within the scope of the present invention. This alternative feed arrangement includes a treatment chamber 12 and heating chamber 15 similar to those described in FIG. 1. The output chamber 14 and related components are also similar to those shown in FIG. 1 and are therefore omitted from FIG. 4. The alternative feed arrangement shown in FIG. 4 includes a feed chamber 95 that is just large enough in diameter to accommodate an impeller 96 similar to impeller 80 described above with reference to FIG. 3. Impeller 96 is driven on a shaft 97 by motor 98 and the shaft is protected by housing 99. Molten reactant metal 16 enters feed chamber 95 through inlet 101 which preferably resides near the level of molten reactant metal maintained in the feed chamber. Impeller 96 is positioned so that it traverses the level of the molten reactant metal 16 in feed chamber 95, and preferably comprises an impeller such as that described in U.S. Pat. No. 4,930,986 to force materials downwardly along axis V in the feed chamber. The illustrated preferred positioning of impeller 96 also allows the impeller to contact and quickly submerge feed materials into the molten reactant metal 16 in feed chamber 95. In other arrangements within the scope of the accompanying claims, the impeller may be located below the level of molten reactant metal in feed chamber 95. In other arrangements within the scope of the invention or set out in the accompanying claim, the impeller may be below the level of molten reactant metal. Feed materials enter feed chamber 95 through feed material conduit 104. A suitable feed material pump 105 pumps or forces feed material from a feed material supply vessel 106 through conduit 104 and into feed chamber 95. Feed material pump 105 may comprise a diaphragm pump or an auger type pump for example. This feed material arrangement shown in FIG. 4 is particularly suited for feed materials in the form of loose particles such as loose soils or feed materials in the form of a slurry. The pumping arrangement for the feed material obviates the need for the purge chamber and dump gate arrangement shown in FIGS. 1 and 3. The positive pressure provided by pump 105 prevents gasses from exiting feed chamber 95 through feed material conduit 104. A pressure relief line 107 with suitable valving may be provided in the top of feed chamber 95 to periodically remove reaction product gasses or other gasses that might collect in the feed chamber. Depending upon the nature of these gasses, the gasses removed through line 107 may or may not be subjected to treatment before release to the atmosphere. In some cases the gasses may simply be directed through particulate control equipment associated with the reactor's reaction product removal equipment shown in FIG. 1. The above described preferred embodiments are intended to illustrate the principles of the invention, but not to limit the scope of the invention. Various other embodiments and modifications to these preferred embodiments may be made by those skilled in the art without departing from the scope of the following claims. For example, the feed pump and feed conduit 104 arrangement shown in FIG. 4 may be replaced by the feed chute and dump gate arrangement shown in FIG. 3, and the feed chambers 11 shown in FIGS. 1 and 3 may include a relief line similar to line 107 shown in FIG. 4. Also, those skilled in the art will appreciate that many technical details have been omitted from the diagrammatic representations shown in FIGS. 1 and 2 in order to avoid obscuring the invention in unnecessary detail. These details such as valves and control systems will be apparent to those of ordinary skill in the art from the above description of molten metal reactor 10.
	claims	1. An emitting capillary discharge source, comprising: an electrode; an insulated capillary discharge chamber having an initial inner bore diameter, the capillary discharge chamber being adjacent to the electrode; a gas for being inserted within the capillary discharge chamber; voltage means for causing a light emission from the capillary discharge chamber; and, means for maintaining the initial inner bore diameter of the capillary discharge chamber inner diameter at a constant value over time, for additional light emissions, the constant value being at least approximately 110% of the initial inner bore diameter for lithographic applications. 2. The emitting capillary discharge source of claim 1 , wherein the constant value is at least approximately 105% of the initial inner bore diameter, for the lithographic applications. claim 1 3. The emitting capillary discharge source of claim 1 , wherein said means for maintaining the initial bore diameter at a constant value is a spring. claim 1 4. The emitting capillary discharge source of claim 1 , wherein said means for maintaining the initial bore diameter at a constant value is selected from one of: a mechanically actuated plunger, and an electrically actuated plunger. claim 1 5. The emitting capillary discharge source of claim 1 , wherein said means for maintaining the initial bore diameter at a constant value includes a remote detector of said light emissions. claim 1 6. The emitting capillary discharge source of claim 1 , wherein the means for maintaining at a constant value provides inwardly directed radial force toward the bore. claim 1 7. The emitting capillary discharge source of claim 1 , wherein the capillary discharge chamber has an inner core diameter between approximately 0.5 mm and approximately 2.5 mm and an overall length which ranges between approximately 1 mm and approximately 10 mm. claim 1 8. The emitting capillary discharge source of claim 1 , wherein said means for maintaining the initial bore diameter at a constant value is a quasi-circularly shaped capillary using elongated segments of capillary material, the ends of which are flat and angularly arranged to form the inner wall of said discharge chamber. claim 1 9. The emitting capillary discharges of claim 8 , wherein there are six of said elongated pieces. claim 8 10. An emitting capillary discharge source, comprising: an electrode; an insulated capillary discharge chamber having an initial inner bore diameter, the capillary discharge chamber being adjacent to the electrode; a gas for being inserted within the capillary discharge chamber; voltage means for causing a light emission from the capillary discharge chamber; and, means for maintaining the initial inner bore diameter of the capillary discharge chamber inner diameter at a constant value over time, for additional light emissions, said means for maintaining the initial bore diameter at a constant value being a spring. 11. An emitting capillary discharge source, comprising: an electrode; an insulated capillary discharge chamber having an initial inner bore diameter, the capillary discharge chamber being adjacent to the electrode; a gas for being inserted within the capillary discharge chamber; voltage means for causing a light emission from the capillary discharge chamber; and, means for maintaining the initial inner bore diameter of the capillary discharge chamber inner diameter at a constant value over time, for additional light emissions, said means for maintaining said initial bore diameter at a constant value being selected from one of: a mechanically actuated plunger, and an electrically actuated plunger. 12. An emitting capillary discharge source, comprising: an electrode; an insulated capillary discharge chamber having an initial inner bore diameter, the capillary discharge chamber being adjacent to the electrode; a gas for being inserted within the capillary discharge chamber; voltage means for causing a light emission from the capillary discharge chamber; and, means for maintaining the initial inner bore diameter of the capillary discharge chamber inner diameter at a constant value over time, for additional light emissions, said means for maintaining the initial bore diameter at a constant value is a quasi-circularly shaped capillary using elongated segments of capillary material, the ends of which are flat and angularly arranged to form the inner wall of said discharge chamber.
	abstract	A phosphosilicate apatite useful as a confinement matrix for radioactive waste, and having the formula:
	abstract	A system includes a beam filter positioning device including a plate configured to support one or more beam filters, and one or more axes operable to move the plate relative to a beam line. A control mechanism is coupled to the one or more axes for controlling the movement of the axes and configured to automatically adjust the position of at least one of the one or more beam filters relative to the beam line.
	abstract	The invention refers to an apparatus (10) for inspecting a sample (12) of a specimen (14) by means of an electron beam (34) comprising a vacuum chamber (18); an ion beam device (20) for generating an ion beam (22) used for etching a sample (12) from the specimen (14) within said vacuum chamber (18); an electron beam device (30) having a scanning unit (32) for scanning the electron beam (34) across said specimen (14) within said vacuum chamber (18); said electron beam device (30) having a first detector (36) positioned to detect electrons (38) that are released from the specimen (14) in a backward direction with respect to the direction of the electron beam (34); and said electron beam device (30) having a second detector (40) positioned to detect electrons (42) that are released from the sample (12) of the specimen (14) in a forward direction with respect to the direction of the electron beam (34); and separation means (50; 52) within said vacuum chamber (18) to separate the sample (12) from the specimen (14) for the inspection of the sample (12) by means of the second detector (40). With the apparatus according to the invention, it is possible to perform a transmission inspection of a sample of a specimen, e.g. a thin slice of a semiconductor wafer, at a high throughput at comparably low costs.
051480328	summary	BACKGROUND OF THE INVENTION 1. Technical Field The present invention relates to a radiation emitting device, and more particularly to a radiation therapy device comprising a radiation source and an aperture plate arrangement located between the radiation source and an object for defining a field of radiation. 2. Description of the Prior Art Radiation emitting devices are generally known and used for instance as radiation therapy devices for the treatment of patients. A radiation therapy device generally comprises a gantry which can be swiveled around a horizontal axis of rotation in the course of a therapeutic treatment. A linear accelerator is located in the gantry for generating a high energy radiation beam for therapy. This high energy radiation beam can be an electron radiation or photon radiation (X-rays) beam. During treatment, this radiation beam is trained on a zone of a patient lying in the isocenter of the gantry rotation. Such a radiation therapy device is described in greater detail in the publication "A Primer on Theory and Operation of Linear Accelerators in Radiation Therapy", U.S. Department of Health and Human Services, Rockville, MD, December 1981. In order to control the radiation emitted toward an object, an aperture plate arrangement is usually provided in the trajectory of the radiation beam between the radiation source and the object. For instance, a wedge-shaped energy dose distribution can be achieved by introducing a wedge-shaped absorption-filter between the radiation source and the object; however, in this case the filter has to be changed in accordance with each desired dose distribution. These dose distributions are commonly defined by isodose curves, measured in water. It is also known to use a moveable aperture plate in connection with a constant radiation source as a substitute for a conventional wedge-shaped filter. U.S. Pat. No. 4,121,109 discloses a radiation therapy device having a aperture plate arrangement in which at least one aperture plate is moveable. Further, from an article "Wedge-Shaped Dose Distribution by Computer-Controlled Collimator Motion" in Medical Physics (5), September/October 1978, pages 426 to 429, it is known to use a defined plate motion to obtain a wedge-shaped isodose curve during irradiation. Such a wedge shaped isodose curve is frequently desired in radiation therapy in order to adjust to the anatomical conditions of the treatment subject. The wedge-shaped isodose curve results from the fact that different areas of the radiation field are exposed to irradiation for varying lengths of time. The requisite motion of the plate is caused by an iterative process. U.S. patent application Ser. No. 07/506,975 entitled "Radiation Therapy Device with Moveable Aperture Plates" by Ernst-Ludwig Schmidt and assigned to the same assignee to the present invention describes a radiation therapy device having an aperture plate arrangement in which at least one aperture plate is moveable and in which in the radiation path a non-moveable filter body is introduced, which has a decreasing absorptivity in the opening direction of the plate. By utilizing this non-moveable filter body, greater flexibility can be achieved in the isodose curves that are to be employed. By this means, it is possible to obtain an isodose curve which, for example, increases in the area to be investigated and then decreases again. Unlike arrangements which have only an exchangeable absorption-filter body and no moveable plate arrangement, a wide variation in the isodose curves can be obtained with plate arrangements using moveable plates. However, such moving plates are rather heavy and therefore sophisticated motor control systems and motors are necessary for moving the plates according to given accurate speed profiles. Furthermore, since radiation is absorbed in the filter body, the efficiency of radiation use is reduced. SUMMARY OF THE INVENTION It is an object of the invention to provide a radiation emitting device which avoids the use of complicated speed profiles, and which nevertheless achieves various isodose curves that are to be employed. According to the invention, the radiation emitting device for irradiating an object with a radiation beam generated in a radiation source comprises an aperture plate arrangement which is located in the trajectory of the radiation beam between the radiation source and the object and which includes a plurality of plates for determining a radiation field at the object. A control unit is provided which is coupled to at least one of the plurality of plates for moving it during irradiation, and which is coupled to the radiation source for changing the dose rate of the radiation beam during irradiation in such a manner that a given dose distribution is obtained in the radiation field. According to a preferred embodiment of the invention the plate speed is kept constant during the plate movement. In this case, the speed control is very simple. The radiation emitting device according to the present invention may be combined with a dosimetry system which detects deviations from a predetermined dose distribution for controlling the radiation therapy device while the dose distribution is generated. This control can be based on the difference between a preset accumulated dose and an actual accumulated dose at every plate position. The radiation emitting device is particularly embodied as a radiation therapy device. By using the invention, in case of a treatment interrupt, the treatment can be continued at the predetermined curve by a re-positioning of the plate to the location where the radiation was turned off. Additional objects and features of the invention will be more readily appreciated and better understood by reference to the following detailed description which should be considered in conjunction with the drawings.
047078464	abstract	A shielding or masking device for use in conjunction with an X-ray radiation generating source comprised of radiopaque material having a vertically oriented opening having a broader portion twice the width of the upper, narrower portion nearer its distal or lower end to block entirely or confine radiation dosage to a specific area of a subject under observation or inspection and to prevent unnecessary and excessive radiation dosages to the subject during full spine radiographs.
052532780	claims	1. A fuel assembly including a lower tie plate, a plurality of fuel rods having the lower end thereof supported by said lower tie plate, fuel spacers for maintaining gaps between said fuel rods, and a channel box having creep deformation inhibition portions formed on the sidewalls thereof and encompassing said fuel spacers, characterized in that said channel box has fuel spacer support means projecting inwardly from an inner surface of said channel box and supporting said fuel spacers in a direction transverse to an axial direction of the fuel assembly. 2. A fuel assembly according to claim 1, wherein said fuel spacer support means includes projections formed by projecting inwardly part of the inner surface of the sidewalls of said channel box. 3. A fuel assembly according to claim 1, wherein said fuel spacer support means includes projections that extend thinly in the axial direction. 4. A fuel assembly according to claim 1, wherein said lower tie plate is equipped on the outer side surface of each sidewall thereof with recesses extending downward from its upper surface, and said creep deformation inhibition portions are fitted into said recesses of said lower tie plate. 5. A fuel assembly according to claim 1, wherein the height of said fuel spacer support means in said axial direction is greater than the height of said creep deformation inhibition portions. 6. A fuel assembly according to claim 1, wherein said creep deformation inhibition portions are formed at the lower part of said channel box, and the gap width between the inner surface of the straight portion of the sidewall of said channel box at the upper part of said fuel assembly and said fuel rods positioned at the outermost periphery is greater than the width between the inner surface of said creep deformation inhibition portions at the lower part of said fuel assembly which is the closest to said fuel rods, and said fuel rods at the outermost periphery. 7. A fuel assembly according to claim 1, wherein said fuel spacer support portions are disposed near the corners of said channel box. 8. A fuel assembly including a lower tie plate, a plurality of fuel rods having the lower end thereof supported by said lower tie plate, fuel spacers for maintaining gaps between said fuel rods, and a channel box encompassing at least said fuel spacers, characterized in that said lower tie plate is equipped on the outer surface side of each sidewall thereof with recesses extending downward from the upper surface of said lower tie plate, and a width between mutually opposed parts of said fuel spacers which come into contact with said channel box when said channel box is fitted thereon is smaller than a width between said receses which are opposite each other. 9. A fuel assembly according to claim 8, wherein said spacer support portions are disposed near the corners of said channel box. 10. A fuel assembly including an upper tie plate, a lower tie plate, a plurality of fuel rods having both end portions thereof supported by said upper and lower tie plates, fuel spacers for maintaining gaps between said fuel rods, and a channel box having creep deformation inhibition portions formed on the sidewalls thereof, characterized in that said channel box has fuel spacer support means projecting inwardly from an inner surface of said channel box and supporting said fuel spacers in a direction transverse to an axial direction of the fuel assembly, and tie plate support means projecting inwardly from the inner surface of the channel box and supporting said upper tie plate in said transverse direction. 11. A fuel assembly according to claim 10, wherein said fuel spacer support means includes projections formed by projecting inwardly part of the inner surface of sidewalls of said channel box. 12. A fuel assembly according to claim 10, wherein said fuel spacer support means includes projections extending thinly in the axial direction. 13. A fuel assembly according to claim 10, wherein said fuel spacer support means are disposed near the corners of said channel box. 14. A fuel assembly according to claim 10, wherein said lower tie plate has recesses extending downward from its upper surface on the outer surface side of each of its sidewalls, and said creep deformation inhibition portions are fitted into said recesses of said lower tie plate. 15. A fuel assembly according to claim 10, wherein the height of said fuel spacer support means in said axial direction is greater than the height of said creep deformation inhibition portions. 16. A fuel assembly including an upper tie plate, a lower tie plate, a plurality of fuel rods having both end portions thereof supported by said upper and lower tie plates, fuel spacers for maintaining gaps between said fuel rods, and a channel box for encompassing the fuel spacers and said upper and lower tie plates characterized in that said lower tie plate has recesses extending downward from its upper surface on the outer side surface of each of its sidewalls, and a width between mutually opposed parts of said fuel spacers which come into contact with said channel box when said channel box is fitted thereon and a width between mutually opposed outer surfaces on the sidewalls of said upper tie plate which come into contact with said channel box are smaller than a width between said recesses which are opposite each other. 17. A fuel assembly according to claim 16, further comprising tie plate support means including projections formed by projecting inwardly part of an inner surface of the sidewall of said channel box. 18. A fuel assembly according to claim 17, wherein said tie plate support means includes projections extending thinly in the axial direction. 19. A fuel assembly including: a plurality of fuel rods; a lower tie plate holding the lower end portions of said fuel rods and having a plurality of coolant supply holes for guiding a coolant between said fuel rods; fuel spacers for maintaining gaps between said fuel rods; and a channel box having creep deformation inhibition portions formed of the sidewalls thereof, and encompassing at its lower end said lower tie plate and thereby forming an coolant leak passage with, and between, said lower tie plate; wherein said channel box has fuel spacer support means that project inwardly from an inner surface of said channel box and supports said fuel spacers in a direction transverse to an axial direction of the fuel assembly, and means for generating a coolant flow for inhibiting coolant leak from said coolant leak passage inclusive of said coolant holes positioned at the outermost periphery among said coolant holes being provided to said lower tie plate. a plurality of first fuel assemblies; and a plurality of second fuel assemblies; each of said first fuel assemblies including: a plurality of fuel rods, first fuel spacers for maintaining gaps between said fuel rods and a first channel box encompassing said first fuel spacers, whereby said first fuel spacers have spacer support means projecting outwardly from an outer surface of said first fuel spacers and come into contact with the inner surface of said first channel box and support said first fuel spacers in a direction transverse to an axial direction; each of said second fuel assemblies including: a plurality of fuel rods, second fuel spacers for maintaining gaps between said fuel rods, and a second channel box having spacer support means projecting inwardly from an inner surface of said second channel box and supporting said second fuel spacers in the direction transverse to the axial direction. 20. A fuel assembly including a lower tie plate, a plurality of fuel rods having the lower end portions thereof supported by said lower tie plate, fuel spacers for maintaining gaps between said fuel rods, and a channel box having creep deformation inhibition portions formed on the sidewalls thereof and encompassing said fuel spacers, characterized in that said fuel spacers are equipped on the spacer sidewalls with resilient members coming into contact with the inner surface of said channel box and supporting said fuel spacers in a direction transverse to an axial direction of the fuel assembly. 21. A channel box including creep deformation inhibition portions formed at the lower part of sidewalls thereof and a plurality of fuel spacer support portions projecting inwardly from the inner surface of the sidewalls. 22. A channel box according to claim 21, further comprising a plurality of tie plate support means projecting inwardly from the inner surface of the sidewalls, for supporting an upper tie plate are provided at the upper end portion of the sidewalls. 23. A channel box according to claim 21, wherein said spacer support portions are capable of supporting a plurality of fuel spacers in a direction transverse to an axial direction and extend thinly in the axial direction and are provided at the upper part of said sidewalls. 24. A channel box according to claim 21, wherein said fuel spacer support portions extend from the lower and to an upper part of said sidewalls. 25. A production method of a channel box characterized in that two U-shaped members are coupled to form a cylinder member and then part of the sidewalls of said cylinder member is projected inwardly from an inner surface of said cylinder member to form a fuel spacer support portion. 26. A production method of a channel box according to claim 25, wherein corrugated portions which are resistant to creep deformation are formed on said sidewalls with the formation of said fuel spacer support portions. 27. A production method of a channel box according to claim 26, wherein said cylinder member having said fuel spacer support portions formed therein is heated to an annealing temperature so as to effect pipe expansion molding. 28. A core of a nuclear reactor comprising: 29. A core of a nuclear reactor according to claim 28, wherein the thickness of said second channel box is smaller than that of said first channel box. 30. A core of a nuclear reactor according to claim 28, wherein a width between the outer surfaces of opposed sidewalls of said second channel box is smaller than the corresponding width of said first channel box and the thickness of said second channel box is smaller than that of said first channel box. 31. A core of a nuclear reactor according to claim 30, wherein the width between the outer surfaces of mutually opposed second sidewalls of said second fuel spacer, which are adjacent to said second channel box, is smaller than the corresponding width of mutually opposed first sidewalls of said first fuel spacer, which are adjacent to said first channel box. 32. A core of a nuclear reactor according to claim 30, wherein said first fuel assembly includes a first lower tie plate having a first insertion portion inserted into a fuel support fixture, said second fuel assembly includes a second lower tie plate having a second insertion portion inserted into a fuel support fixture, the axis of said first insertion portion is in agreement with the axis of said first fuel assembly and the axis of said second insertion portion is deviated from the axis of said second fuel assembly toward a control rod inserted between said first and second fuel assemblies. 33. A core of a nuclear reactor according to claim 28, wherein a width between the inner surfaces of mutually opposed sidewalls of said second channel box is greater than the corresponding width of said first channel box and the thickness of said second channel box is smaller than that of said first channel box.
	description	The invention utilizes a reactant alkaline metal alloy composition including one or more chemically active alkaline metals and one or more radiation absorbing metals. Alkaline metals are included for chemically reacting with hydrocarbon and other non-radioactive wastes in a waste stream and for facilitating the alloying of radioactive isotopes. Radiation absorbing metals generally do not react chemically in any substantial degree with any material in the waste stream and are included in the reactant alloy only for their radiation absorption characteristics. Also, the radiation absorbing metals are matched by their radiation absorption characteristics to radioactive isotopes to be added to the reactant alloy and, more particularly, to the radioactive emissions expected within the resulting alloy. The chemically active alkaline metal or metals in the reactant alloy may comprise, aluminum, magnesium, lithium, calcium, iron, zinc, and copper. The aluminum, magnesium, and /or lithium in the reactant alloy react with halogenated hydrocarbons, to produce aluminum, magnesium, and/or lithium salts. Calcium, iron, zinc, and copper in the reactant alloy may react with certain non-radioactive constituents in the waste material, but are primarily included as stabilizing agents for the aluminum, magnesium, and/or lithium in the reactant alloy. The radiation absorbing metal or metals in the reactant alloy may comprise particular isotopes of beryllium, cadmium, vanadium, yttrium, ytterbium, zirconium, tungsten, or lead. Various isotopes of these metals exhibit a low fission neutron cross section which allows them to absorb radioactive emissions to produce either a stable isotope or an isotope which emits only relatively low energy radiation. Table 1 shows a list of preferred radiation absorbing metals which may be employed in the reactant metal alloy within the scope of the invention. Table 1 also lists the particular radioactive emissions which each radiation absorbing metal is capable of absorbing. The particular radiation absorbing metal or metals chosen for an application will depend upon the nature of the radioactive isotopes in the waste stream being treated. Specifically, a radiation absorbing metal is included in the reactant alloy for each corresponding expected radioactive emission. Thus, for each type of expected radioactive emission associated with an isotope added to the alloy, an absorbing metal is included for absorbing that particular type of radioactive emission. Those skilled in the art will appreciate that many of the above-identified preferred radiation absorbing metals are themselves unstable isotopes and are subject to radioactive decay. However, the emission energies associated with these isotopes are sufficiently low to avoid substantial radiation leakage from the resulting storage product and mechanical degradation of the storage product. The alloy produced according to the invention includes sufficient radiation absorbing metal for each corresponding expected emission to maintain a minimum ratio of radiation absorbing metal atoms to the respective corresponding expected radioactive emissions. The preferred ratio is no less than seven hundred and twenty-seven (727) atoms of radiation absorbing metal for each corresponding expected radioactive emission. Higher ratios may also be used within the scope of the invention. As radioactive isotopes are alloyed into the reactant alloy, the atoms of radioactive material are incorporated into the matrix of the reactant alloy and isolated among the atoms of metals in the reactant alloy. Most importantly, the atoms of radioactive isotopes are substantially distributed and isolated among the atoms of corresponding radiation absorbing metal in the alloy. As used herein to describe the radioactive isotopes added to the molten metal bath, the term xe2x80x9calloyedxe2x80x9d means dissolved or otherwise dispersed and intimately mixed with the molten reactant metal. This dispersion and resulting isolation of the radioactive isotopes in the reactant alloy matrix among the corresponding radiation absorbing metals at the desired minimum ratio helps ensure that most radioactive emissions from the radioactive isotopes will be captured within the reactant alloy storage product, thereby reducing overall radioactive emissions from the storage product. The specific absorbing metals absorb the radioactive emissions without substantially reducing the mechanical integrity of the storage product. The reactant alloy may include one or more of the following chemically active alkaline metals in the indicated concentration range: between about 1% to 25% zinc, between about 1% to 25% calcium, between about 1% to 25% copper, between about 1% to 25% magnesium, between about 1% to 25% lithium, and between about 10% to 90% aluminum. The reactant alloy may include one or more of the following radiation absorbing metals: lead, tungsten, beryllium, cadmium, vanadium, yttrium, ytterbium, and zirconium. Each of these radiation absorbing metals will commonly be present in the reactant alloy in a concentration range of between about 1% to 25% of the total alloy. All percentages used in this disclosure are by weight of the total reactant alloy. Table 2 sets out nine different preferred reactant alloys tailored for various waste streams. Each percentage in Table 2 refers to the percentage of a particular radiation absorbing isotope chosen from Table 1. Table 3 indicates the particular applications for which the alloys shown in Table 2 are tailored. Reactant alloys III, VI, and VII are preferably used at an operating temperature of about 1000 degrees Celsius. Reactant alloy IV is preferably used in the process of the invention at an operating temperature of 850 degrees Celsius, while alloy V is used at an operating temperature of 900 degrees Celsius. The operating temperature for a particular treatment process according to the invention is chosen based both upon the constituents of the waste stream and the reaction products to be produced in the process. Higher operating temperatures may be required to break double and triple carbon bonds and other types of chemical bonds in the molecules of waste material being treated. Higher operating temperatures also generally allow the radioactive constituents in the waste stream to better dissolve or melt into the reactant metal alloy. Also, the operating temperature may be increased to allow certain reaction products to go to a gaseous state and then be removed from the reactant alloy container in the gaseous form. Another preferred reactant alloy according to the invention is tailored for processing waste streams containing relatively high gamma radiation emitting isotopes at 0.72 MeV and higher. This preferred alloy includes about 25% lead (197-207), about 25% tungsten (173-183), and about 50% chemically active metal. The chemically active metal may comprise aluminum and/or magnesium. As indicated by the example reactant metal alloys shown in Tables 2 and 3 and discussed above, the amount of chemically reactive metal in the alloy preferably always makes up approximately 40% or more of the alloy by weight. This level of chemically active metal in the reactant alloy is helpful in dissolving the metal radioactive constituents in the waste stream. The dissolved radioactive constituents may then be dispersed freely throughout the molten metal to produce the desired storage alloy. The radioactive material storage product comprises one or more chemically active metals and one or more radioactive isotopes. Also, for each type of expected radioactive emission in the volume of the storage product, the product further includes a corresponding radiation absorbing metal adapted to absorb the respective radioactive emission. The corresponding radiation absorbing metal may be adapted to absorb radioactive emissions from different isotopes, and thus the storage product will not always include a separate radiation absorbing metal for each isotope. Rather, one radiation absorbing metal may be capable of absorbing two or more types (that is, type and energy level) of radioactive emissions in the storage product. In any event, the storage product includes at least about 727 atoms of radiation absorbing metal for each corresponding expected radioactive emission. With each reactant metal alloy composition according to the invention, the alloy is heated to a molten state to prepare the material for receiving the waste stream. Typically, the temperature of the molten alloy must be maintained at no less than 770 degrees Celsius in order to provide the desired reaction with organic molecules in the waste material. Higher temperatures for the molten alloy may also be used within the scope of the invention as discussed above with reference to Table 3. Lower temperatures may also be used where relatively few non-radioactive constituents are included in the waste stream or only relatively light hydrocarbons are included in the waste. In any event, the operating temperature should be a temperature sufficient to place the particular reactant metal alloy in a molten state and sufficient to allow the radioactive metals in the waste material to dissolve or melt into the bath. The reactant metal alloy treatment process according to the invention may be used to treat many types of radioactive waste materials and mixed waste streams including both radioactive waste and non-radioactive waste. The treatment process is particularly well adapted for treating wastes which include radioactive constituents mixed with halogenated hydrocarbons. The radioactive isotopes may comprise any isotopes which may be alloyed into the particular molten reactant metal including, for example, isotopes of plutonium, radium, and rhodium. Certain radioactive isotopes may not alloy into the molten reactant metal. Where these isotopes react with metals in the bath to form reaction products which remain in solid or molten form, these reaction products may be thoroughly mixed with the molten reactant metal and then cooled while mixed to produce relatively low emission ingots. Any gaseous reaction products which include radioactive isotopes will be entrained with the non-radioactive gaseous reaction products. Some gaseous radioactive isotopes may be absorbed from the reaction product gas. For example, tritium may be absorbed by palladium placed in the stream of gaseous reaction products. However, it is desirable to maintain the operating temperature of the molten reactant metal low enough to reduce the amount of radioactive isotopes which go into gaseous reaction products. For example, where a radioactive isotope of iodine is included in the waste stream, the chemically active metal in the alloy may include aluminum and the operating temperature is maintained low enough to ensure that the resulting aluminum iodide remains primarily in a molten state. The aluminum, magnesium, or lithium in the reactant alloy according to the invention strips halogens from the halogenated hydrocarbons in the waste stream to produce halogen salts. Other elements in the non-radioactive waste material, such as phosphorous, sulphur, and nitrogen, are also stripped from the carbon atoms in the waste material. Much of this other stripped material forms metal salts (sulfates, nitrates, phosphates) which separate from the molten reactant metal by their respective density. Where these separated materials include only non-radioactive constituents they may be separately drawn or scraped from the molten reactant metal by any suitable means. Most of the halogen salts and char go to a gaseous state and are drawn off for separation and recovery. Any low boiling point metals, such as arsenic or mercury, for example, which are liberated from the waste materials are also drawn off in a gaseous state for recovery. Non-radioactive, relatively high boiling point metals such as chromium, and radioactive metals in the waste material remain safely in the molten alloy. The original metals which make up the alloy remain in the molten alloy unless consumed in the formation of salts and small quantities of oxides. The treatment process according to the invention is illustrated in FIG. 1. The waste material to be treated is first analyzed to identify the types and concentrations of non-radioactive chemicals and radioactive isotopes present in the waste. This analysis step is shown at dashed box 101 in FIG. 1. Information regarding the types and concentrations of non-radioactive constituents in the waste material is used to help choose the types of chemically active metals to be included in the molten reactant alloy. Information regarding the radioactive isotopes in the waste material determines the amount and type of radiation absorbing metals to be included in the molten reactant alloy. The types and concentrations of radioactive isotopes and non-radioactive chemicals in the waste material are preferably determined using an analytical technique such as mass spectroscopy at step 101. Of course, any analytical technique will be limited to certain minimum detection levels below which an isotope or chemical cannot be detected. The concentration of radioactive isotopes detected in the waste stream is then used at step 103 to produce an estimate of the quantity or amount of each radioactive isotope present in the waste per unit volume or weight. Once the amount and type of non-radioactive constituents and radioactive isotopes in the waste material are known, the reactant metal alloy for treating a selected volume or weight of the particular waste material is constructed at step 104. Specifically, a reactant metal alloy is built with chemically active metals for reacting with the non-radioactive constituents in the waste material and with sufficient radiation absorbing metals to produce the desired storage product. With the reactant alloy built for the particular waste and held in a molten state at the desired operating temperature, the process includes metering the waste material into the molten reactant metal at step 105. Any suitable metering device may be used to perform the metering step according to the invention. Preferably, the metering device provides a continuous output of volumetric information (or weight information if it is desired to meter the waste stream by weight). Since the amount of waste material which may be added to the molten reactant alloy to produce the desired storage product (desired minimum ratio) is known, waste material may be metered into the reactant alloy until that known amount is reached. Alternatively, the continuous output showing the cumulative amount of waste added to the reactant alloy may be used at step 106 to calculate the total radioactive isotopes in the alloy and the ratio of radiation absorbing atoms to corresponding expected radioactive emissions at step 106. This calculation step also requires the radioactive isotope concentration or amount information from step 103 and the alloy information from step 104. The calculation may be performed using a suitable processor (not shown) connected to receive the required inputs, or may be performed manually. The calculated ratio or the cumulative amount may be compared to a corresponding set value at step 107 to provide a control signal which may be used to automatically stop the introduction of waste material into the reactant alloy. The metered amount of waste material is added to the molten reactant metal at step 108 in FIG. 1. Also, the preferred form of the invention includes a separate emission monitoring step to monitor radioactive emissions from the waste material stream as it is being directed to the molten reactant alloy. This separate monitoring step, 108 in FIG. 1, may be performed is using any suitable radioactive emission detector to detect anomalous high concentrations of radioactive isotopes. Suitable devices include gas-filled, scintillation, or semiconductor type detectors. Regardless of the detector type, an unexpected spike in radioactive emissions may be used at decision box 109 to produce a control signal to stop the waste stream from being introduced into the reactant alloy. This control signal may be automated or may be made manually by an operator overseeing the treatment process. In the preferred treatment process according to the invention, the reactant metal alloy composition is contained in a reactant alloy container such that the alloy is substantially isolated from oxygen. The reactant alloy is then heated by a suitable heating arrangement to the desired operating temperature, which is generally greater than 770 degrees Celsius as discussed above. Any remaining oxygen in the reactor vessel quickly reacts with the metal in the alloy to produce metal oxides which appear as slag at the surface of the molten material or sink to the bottom of the reactant alloy container. In the preferred process, a layer of pure carbon in the form of graphite is placed at the surface of the molten reactant metal alloy. The graphite layer may be from approximately one-quarter inch to several inches thick and helps further isolate the molten alloy from any oxygen which may be in the reactant alloy container. Once the molten alloy reaches the desired operating temperature, the waste material is introduced into the reactant molten alloy to perform the contacting step shown in FIG. 1. The waste material is preferably introduced below the surface of the molten alloy but may be introduced at the surface of the alloy within the scope of the invention. The temperature of the metal alloy is maintained at least at the desired operating temperature as waste material is added to the molten alloy. Heat will commonly need to be added continuously by the heating arrangement in order to maintain the desired operating temperature. Also, it will be appreciated that pockets of relatively cooler areas may form momentarily in the reactant alloy as waste material is added. The bulk of the reactant alloy, however, is maintained at least at the desired operating temperature. A suitable mixing arrangement may be used with the reactant alloy container to ensure that the relatively cool waste material is distributed quickly within the reactant alloy and to ensure that the radioactive isotopes and radiation absorbing metals are evenly distributed within the alloy. A mechanical stirring device (not shown) to continuously stir the molten material provides a suitable mixing arrangement. Once the desired minimum level of radiation absorbing metal to corresponding expected radioactive emissions is reached for a given volume of reactant alloy according to the invention, the waste stream is halted and the reactant alloy cooled to form one or more solid ingots of the storage material. Where isotopes of cadmium are to be included in the storage product, it is necessary to cool the molten metal to a temperature low enough to allow the cadmium to go to a molten form (725 to 765 degrees Celsius). Thereafter, the molten material may be thoroughly mixed prior to further cooling. The resulting solid ingots each include unreacted alkaline metals, the radiation absorbing metals, and the radioactive isotopes from the waste stream, all substantially evenly distributed. Each ingot is preferably encapsulated with a radiation absorbing encapsulant material for storage. The encapsulant material preferably includes a material or combination of materials which together are capable of absorbing each type of radioactive emission expected from the resulting ingot. FIG. 2 shows an apparatus for performing a treatment process embodying the principles of the invention. The apparatus includes a reactant alloy container 202, a recovery/recirculation arrangement 240, a feed arrangement 241, and a heating arrangement 242. The reactant alloy container 202 is preferably built from a suitable metal which will maintain structural integrity at the desired elevated temperatures. However, due to the highly reactive nature of the alloy 210, the reactant alloy container 202 is lined with a ceramic or other suitable refractory material to prevent the metal of the container from reacting with the reactant alloy. Also, due to the radioactive material to be alloyed in the process, container 202 also preferably includes a layer S of suitable radiation absorbing shielding. This shielding is adapted to block or absorb each type of radioactive emission which may emanate from the interior of container 202. A cover 203 is connected over container 202 for collecting gaseous reaction products and helping to isolate the metal bath from oxygen. Although not shown in the drawing, radiation shielding material is also preferably included in cover 203 and with the feed arrangement 241. An expendable hook 205 may be placed in the alloy 210 at the termination of the process and, after cooling, may be used to lift the solidified alloy ingot from the reactant alloy container 202. Alternatively, a suitable drain may be included in container 202 for draining off reactant alloy once the desired minimum ratio of radiation absorbing atoms to corresponding radioactive emissions is reached. Solids may be mixed with liquids to form a slurry and the slurry introduced similarly to liquid wastes as discussed below. Also, solids either alone or in the form of a slurry may be introduced into the container 202 through an auger arrangement or other suitable arrangement such as that shown in U.S. Pat. No. 5,431,113, the disclosure of which is hereby incorporated herein by this reference. The heating arrangement 242 includes an induction heater, including an induction heater power supply 206 and induction coils 204 built into the reactant alloy container 202. The coils 204 may be water-cooled and the water may be used to cool the reactant alloy 210 as desired, either during the treatment process or at the completion of the treatment process. The induction heater arrangement 242 includes a heater control 209 with a suitable sensor 209a inside the reactant alloy container 202 for controlling the induction heater and maintaining the temperature of the metal alloy 210 at the desired operating temperature. Although the induction heating arrangement is illustrated in FIG. 1, any suitable heating arrangement, including a fossil fuel burning heater may be used to heat the alloy 210 to the desired temperature. U.S. Pat. No. 5,452,671 to the present inventor illustrates a fossil fuel fired heating arrangement which may be used according to the present invention. The disclosure of U.S. Pat. No. 5,452,671 is hereby incorporated herein by this reference. The feed arrangement 241 includes feed tank 212 and feed coil 208. Feed tank 212 contains waste material to be processed. A feed pump 214 pumps the waste material from feed tank 212 to the reactant alloy container 202 through a metering device 215. Metering device 215 serves two functions. First, metering device 215 is operated to meter waste material into the reactant alloy at a rate which does not exceed the capacity of the heater arrangement 242 to maintain the desired operating temperature in the molten reactant metal 210. Second, metering device 215 provides information regarding the amount of waste material added to the molten reactant metal. This quantity information may be used to calculate the ratio of radiation absorbing atoms in the alloy 210 to the atoms of corresponding expected radioactive emissions. As described above with reference to FIG. 1, the ratio calculations are preferably computed automatically and continuously in a suitable control processor shown at reference number 243 in FIG. 2. Control processor 243 also receives information concerning the radiation absorbing metals in container 202 and information concerning the concentration (or amount) of various radioactive isotopes in the waste material to be treated. Alternatively to calculating the ratio as waste material is being added to the molten metal bath, the quantity information used to build the molten reactant alloy can be used to limit the amount of waste material metered through metering device 215. Feed system 241 also preferably includes a radioactive emission monitoring device 244 connected in position to monitor the stream of waste material being directed to the molten metal 210 for treatment. Monitoring device 244 may be located in a recirculation manifold shown generally at 245. Should monitoring device 244 detect a spike in radioactive emissions from the waste stream, controller 243 (or an operator) may close valve 245a and open valve 245b to circulate the waste stream back to feed tank 212. Alternatively to the manifold arrangement, the feed pump 214 can simply be turned off to halt the flow of waste material into the reactant alloy 210. Feed coil 208 is coated on its interior and exterior surfaces or formed from a ceramic or other suitable refractory material to prevent the coil from reacting with the molten alloy 210 in container 202. The outlet end of the coil is preferably positioned well below the surface of the alloy 210 to ensure good contact between the waste material and molten reactant metal 202. The feed system 241 also preferably includes a gas purging arrangement including a gas storage cylinder 216 for containing a suitable purge gas such as nitrogen. The gas purging arrangement is operated to purge the feed lines and coil 208 of air prior to operation of the system. Gases other than nitrogen may be used to purge the system of oxygen, including flue gases from a fossil fuel burning heater arrangement. The recovery/recirculation system 240 includes an aqueous scrubber/separator 224, a char/water separator 230, a salt recovery arrangement 231, and a recirculation arrangement 232. Off-gas from the area above the molten alloy 210 in container 202 comprising gaseous halogen salts, char, and other gases are drawn off through line 218. Line 218 is preferably made of stainless steel and includes a relief valve 220 to maintain atmospheric pressure on line 218. A water spray nozzle 222 is associated with the scrubber/separator 224 and serves to spray water into the off-gas at the inlet to the scrubber/cyclone separator. The water sprayed into the off-gas causes the char to coalesce while the salt in the off-gas goes into solution in the water. The amount of water supplied through nozzle 222 is preferably controlled with temperature controller 223 to maintain the temperature below about 100 degrees Celsius in the scrubber/separator 224. A char slurry forms in the bottom of the scrubber/separator 224 and is drawn off through valve 226. The slurry comprises char and water with salt in solution. The char slurry is directed to char/water separator 230 which separates out the fine char particles from the water solution and passes the water solution through pump 233 on to salt recovery system 231. Salt recovery system 231 may comprise an evaporative system. Water from salt recovery system 231 may be recycled to nozzle 222. Any gas from separator/scrubber 224 may be vented to the atmosphere through a suitable radiation monitoring arrangement (not shown). Alternatively, gas from separator/scrubber 224 may be drawn off through recirculation fan 228 and reintroduced to the area above the molten alloy 210 for recycling through the system. A waste material is analyzed with a mass spectrometer and found to comprise thorium 229 at 9 parts per million (ppm), PCBs at 500 ppm, and creosote at 1000 ppm in water. To treat one ton of the waste material, a molten reactant metal according to the invention may include predominantly aluminum and perhaps small percentages of zinc, iron, copper, and calcium. The primary emissions of thorium 229 include alpha particles at 5.168 MeV. Beryllium 11 is added to the molten reactant metal as a corresponding absorber for the alpha emissions and lead 206 is added to absorb the primary gamma emissions from the thorium 229 and secondary gamma emissions as the alpha particles interact with materials in the bath. The 9 ppm of thorium 229 equates to 6.412 grams of the isotope per ton of the waste material. 6.42 kilograms of beryllium 11 is included in the metal bath to provide a one thousand to one correspondence between the beryllium and the expected alpha emissions. 12.84 kilograms of lead 206 is included in the metal bath to provide a one thousand to one correspondence between the lead and the expected primary and secondary gamma emissions. The above described preferred embodiments are intended to illustrate the principles of the invention, but not to limit the scope of the invention. Various other embodiments and modifications to these preferred embodiments may be made by those skilled in the art without departing from the scope of the following claims. For example, although the invention is described above with the reactant alloy being heated to a molten state in the reactant alloy container, the alloy constituents may be heated to a molten state together or individually outside the reactant alloy container and added to the container as a molten material. Heating the reactant alloy metals outside of the reactant alloy container is to be considered an equivalent to the embodiment in which the metals are initially heated to the molten state within the reactant alloy container. Furthermore, constituents of the desired reactant metal alloy may be added while the waste material is being added. Adjusting the reactant alloy of the bath after some waste material has been added is to be considered equivalent to adding the waste material to a completely pre-built reactant metal bath. Also, numerous solid and liquid recovery arrangements may be used within the scope of the invention instead of the example arrangement 240 shown in FIG. 2.
	description	The present invention relates to an apparatus and a method for producing of test for the nuclear power plant, and more particularly, to producing technology for fibrous debris of test for evaluating an accident such that fibrous debris generated due to a loss of coolant accident in a nuclear power plant passes through a sump strainer and is deposited on the reactor core region. After the occurrence of a loss of coolant accident in the reactor building, the cooling water injected into the reactor core through the emergency core cooling system or sprinkled through the containment spray system is collected in the containment sump, and the collected water is used as a suction source of the emergency core cooling system pump. In general, a sump is equipped with a strainer to protect the emergency core cooling system-related apparatus during recirculation operation from various debris generated during a virtual pipeline rupture such as a loss of coolant accident and moved to a containment sump. The various debris generated during a virtual pipeline rupture accident and moved to a containment sump are screened by the strainer, however the debris of a size smaller than a mesh of the strainer can be passed through the strainer, and deposited on the reactor core region. Consequently, the deposited substances may block the flow path and affect core cooling ability in the long term. Tests are required for evaluating the influence of debris in the core due to a loss of coolant accident. And then tests are conducted by varying debris composition and flow rate. Fibrous type debris, particle type debris, and compound debris can be used for tests. Among the debris used in tests, a fibrous substance has the most dominant influence on the clogging of the core inlet, and the core inlet is clogged depending on the length distribution of the debris. Accordingly there is a pressure difference of the water supplied to the core. In the test facility for evaluating the influence of debris in the core due to a loss of coolant accident, if the length distribution of the fibrous debris is not controlled, the test reproducibility cannot be ensured. Accordingly, there may be a problem that conservative experimental data cannot be produced. Accordingly in the present invention, after fibrous debris of test having a uniform length distribution is produced, it is used for a test for evaluating the influence of debris in the core due to a loss of coolant accident based on the produced fibrous debris for testing, thereby, ensuring reproducibility of a test for evaluating the influence of debris in the core due to a loss of coolant accident and suggesting a solution for producing conservative experimental data. The present invention has been made in consideration of the above problems, and it is an object of the present invention to provide an apparatus and a method for producing a test debris for a nuclear power plant for securing reproducibility of a test evaluating differential pressure change of water supplied to the core and for producing conservative experimental data by producing fibrous debris of test having the length distribution equal to the length distribution of fibrous debris passed through a strainer and by testing for evaluating the influence of debris in the core due to a loss of coolant accident with the produced fibrous debris for testing as an input element. In order to accomplish the above technical object, an apparatus for producing a test debris for a nuclear power plant comprises: a plurality of fibrous debris strainer bags for collecting fibrous debris passed through a sump strainer, and further comprise: a sample fibrous debris deriving unit for measuring the length distribution of fibrous debris collected in a plurality of the strainer bags, and deriving a sample fibrous debris by removing a distorted length distribution among the measured length distribution of fibrous debris; and a fibrous debris producing unit for producing fibrous debris of test having a uniform length distribution equal to the length distribution of the sample fibrous debris of the sample fibrous debris deriving unit and using the fibrous debris for the core downstream type effect test. Preferably, the sample fibrous debris deriving unit may comprise: a length distribution measuring unit for measuring the length distribution of the collected fibrous debris; a filtering unit for removing fibrous debris in a distorted length distribution region and extracting the length distribution of fibrous debris within a predetermined critical range with respect to the length distribution of the measured fibrous debris; and a sample fibrous debris generating unit for setting the length distribution of the fibrous debris passed through the filtering unit as the length distribution of the sample fibrous debris. Preferably, the fibrous debris producing unit is provided to produce fibrous debris of test by pulverizing aged fiber so that the fibrous debris of test can have the length distribution of the sample fibrous debris, and the fibrous debris producing unit may comprise: a cutter for cutting aged fiber to a predetermined size; a weighing scale for selecting fiber of a predetermined weight by measuring the weight of the cut fiber of a predetermined size; a controller for setting the pre-stored applied voltage and the pulverization time according to the type of strainer; and a pulverizer for pulverizing fiber of a certain weight based on the voltage applied to the controller and the pulverization time for pulverizing the fiber having a predetermined weight and size to the length distribution of the sample fibrous debris. The controller measures the length distribution of the fibrous debris pulverized by the pulverizer, and judges whether the measured fibrous debris length distribution coincides with the length distribution of the sample fibrous debris. In case coincidence occurs, the applied voltage and the pulverization time of the pulverizer may be stored in a predetermined memory area with the matched type of strainer. A method of producing fibrous debris based on the apparatus as described above comprises the following steps: (A) collecting fibrous debris passed through a strainer in a plurality of strainer bags; (B) measuring the length distribution of the fibrous debris collected by the sample fibrous debris deriving unit; (C) removing fibrous debris in a distorted length distribution region with respect to the length distribution of the measured fibrous debris and setting the length distribution of the fibrous debris within a predetermined critical range to the length distribution of the sample fibrous debris; and (D) generating fibrous debris of test having a uniform length distribution equal to the length distribution of the sample fibrous debris in the fibrous debris generating apparatus. Preferably, the step (D) may comprise the steps of cutting given aged fiber to a predetermined size; measuring the weight of the cut fibers of a predetermined size so as to select fibers of a predetermined weight; controlling pulverization for setting a predetermined applied voltage and pulverization time according to the type of strainer; and pulverizing for producing fibrous debris of test having a uniform length distribution equal to the length distribution of the sample fibrous debris with the fibers having a predetermined weight based on the applied voltage and the pulverization time. In addition, the step (D) measures the length distribution of the fibrous debris pulverized by the pulverizer, judges whether the measured fibrous debris length distribution coincides with the length distribution of the sample fibrous debris, and stores the applied voltage and the pulverization time of the pulverizer in a predetermined memory area by matching with the type of strainer in case coincidence occurs. According to the embodiment of the present invention as described above, fibrous debris of test having the uniform length distribution equal to the fibrous debris collected by a plurality of strainer bags while passing through a strainer is produced, and a test for evaluating the influence of debris in the core due to a loss of coolant accident is conducted based on the produced fibrous debris for testing, thereby ensuring reproducibility of a test for evaluating the influence of debris in the core due to a loss of coolant accident and, thereby producing conservative experimental data. Specific features and advantages of the present invention will be clearly described in the description with respect to the accompanying drawings. The terms and words used in the present specification and claims are to be construed in accordance with the technical idea of the present invention based on the principle that the inventor can properly define the concept of the term in order to explain the invention in the best way. It should be construed in terms of meaning and concept. In the following description, well-known functions or constructions are not described in detail to avoid obscuring the subject matter of the present invention. FIG. 1 is a diagram showing the configuration of a test debris producing apparatus for a nuclear power plant according to an embodiment of the present invention, and FIG. 2 is a diagram showing a detailed configuration of a sample fibrous debris deriving unit shown in FIG. 1. A fibrous debris of test producing apparatus for a nuclear power plant according to an embodiment of the present invention is provided to produce fibrous debris of test having a uniform length distribution equal to the length distribution of fibrous debris passing through a strainer, collected by a plurality of strainer bags and conduct a test for evaluating the influence of debris in the core due to a loss of coolant accident based on produced fibrous debris for testing. The apparatus comprises a plurality of strainer bags 10, a sample fibrous debris deriving unit 30, and fibrous debris producing unit 50. A plurality of strainer bags 10 are provided to collect fibrous debris passed through a strainer and the collected fibrous debris is transferred to a sample fibrous debris deriving unit 30. Accordingly, when fibrous debris passed through the strainer is collected, the fibrous debris screened by at least two strainer bags is all collected. At this time, there can be loss of fibrous debris in case collecting is conducted with a strain bag 10 in a dried condition. For example, there is limit to collecting small fibrous debris less than 50 μm. Accordingly, such fibrous debris can be conducted by using water flowing backward. And the mass of dried strainer bags before the collection of fibrous debris is measured, the mass of collected fibrous debris after the collection is measured, and the collected fibrous debris mass and non-collected fibrous debris mass are recorded in a predetermined memory area. In this case, the strainer bag 10 filters fibrous debris having length longer than 1 μm, and there is fibrous debris which is not retrieved during the collection of fibrous debris having length less than 200 μm and remains. Accordingly, the sample fibrous debris deriving unit 30 generates a difference from the length distribution degree of the population due to the fibrous debris of such a small size collected in the region. Therefore, the length distribution of the region is removed, and the sample fibrous debris of the removed length distribution is set. As shown in FIG. 2, the sample fibrous debris deriving unit 30 comprises the length distribution measuring unit 31 for measuring the length distribution of the collected fibrous debris, a filtering unit 32 for removing the length distribution out of a predetermined critical range of length distribution degree, and a sample fibrous debris generating unit 33 for setting fibrous debris having the length distribution within a critical range to sample fibrous debris. At this time, the number of the collected fibrous debris should be at least 30,000 or more. Since the distribution degree meter 31 has a high possibility of generating the length distribution degree that deviates from the critical range due to the measurement error and the limitation of the number of objects to be measured, an optical microscope for manual measurement is not used but a fiber length measuring device such as a fiber tester is used. Accordingly, the measurement error of the length of the fibrous debris can be minimized and the possibility of generating the length distribution degree that deviates from the critical range due to a large number of objects to be measured can be reduced. In addition, the sample fibrous debris deriving unit 30 generates sample fibrous debris having representativeness of the length distribution degree by generating respectively the length distribution of fibrous debris collected in at least two strainer bags and determining the representativeness of the length distribution. FIG. 3 is a view showing the length distribution degree of fibrous debris measured with the length distribution measuring unit 31. The length distribution is calculated by summating the number of objects to be measured per interval unit of 10 μm and expressed as a percentage. FIG. 4 is a diagram showing degree of length distribution of sample fibrous debris and shows that the sample fibrous debris is set by removing the fibrous debris region where the length distribution degree is smaller than 200 μm in the degree of length distribution of fibrous debris shown in FIG. 3. That is, since the number of objects to be measured is small in a region smaller than 200 μm, the difference from the actual degree of fibrous debris distribution occurs. Accordingly, fibrous debris having the length distribution degree in a critical range excluding a distorted region is determined as a sample fibrous debris by judging a region smaller than 200 μm as a distorted region. FIG. 5 is a diagram showing a detailed configuration of the fibrous debris producing unit 50 shown in FIG. 1. As shown in FIG. 5, the configuration is provided to produce fibrous debris of test having the length distribution degree of sample fibrous debris generated from sample fibrous debris deriving unit 30. Accordingly, the fibrous debris producing unit 50 comprises a cutter for cutting fibers to a predetermined size; a weighing scale 52 for selecting fiber of a predetermined weight by measuring the weight of the cut fiber of a predetermined size; a controller for controlling an applied voltage and pulverization time of the pulverizer for pulverizing the fibers having a certain weight and size by the length distribution of the sample fibrous debris; and a pulverizer 54 for pulverizing in the basis of the applied voltage and pulverization time fibers of a certain weight selected for generating fibrous debris of test which are uniform and have the same distribution as the sample fibrous debris. The aged fiber for an in-reactor downstream effect test is cut by the cutter 51 to a uniform size. That is, the fibers to be cut are cut to the length and width of 2.5 cm*2.5 cm, and the cut fibers are transferred to the weighing scale 52. The weighing scale 52 provides a pulverizer 54 with a predetermined amount at least 3 g of the fibers cut by the cutter 51. The predetermined amount is set to a one-time pulverizing amount, and the amount is set to be 1% larger than the predetermined amount in consideration of the loss amount during pulverization. In addition, the one-time pulverizing amount may vary depending on a pulverizer, and it is limited to be smaller than a certain amount in consideration of the reproducibility of the test. Since the pulverization length of the fiber is determined according to the pulverization time and the applied voltage at the pulverizer 54, the control unit 53 sets the pulverization time and the applied voltage based on the type of strainer. In addition, the length of the produced fibrous debris varies according to the kind of the pulverizer, but the applied voltage rather than the pulverization time affects the length distribution of the produced. Accordingly, the fibrous debris is pulverized by the constant pulverizing time and the varying applied voltage. In other words, the power supply of 200 V and the applied voltage are varied by 10 V, 60 V, and the like. On the other hand, the fibrous debris of test pulverized in the pulverizer 54 is judged by the controller 53 whether the length distribution of the fibrous debris of test equals to the length distribution of the debris of the sample fibrous debris. As shown in FIG. 3, the length distribution degree of the fibrous debris of test produced through the pulverizer 54 shows a conservative result when there is a lot of debris having a large length and the number of objects in the region larger than 1 mm is larger than the number of sample fibrous debris. In case, by the judgment of the controller 53, the length distribution of the fibrous debris of test and the length distribution of the sample fibrous debris coincide with each other, the applied voltage and the pulverization time of the pulverizer 54 are stored in a predetermined memory area by matching with the type of strainer. The controller 53 measures the length distribution of the fibrous debris pulverized by the pulverizer 54, and judges whether the measured fibrous debris length distribution coincides with the length distribution of the sample fibrous debris. In case coincidence occurs, the applied voltage and the pulverization time of the pulverizer are stored in a predetermined memory area. The produced debris for testing is used for the downstream effect test in the core. Accordingly, fibrous debris of test having the uniform length distribution equal to the fibrous debris collected by a plurality of strainer bags while passing through a strainer is produced, and a test for evaluating the influence of debris in the core due to a loss of coolant accident is conducted based on the produced fibrous debris for testing, thereby ensuring reproducibility of a test for evaluating the influence of debris in the core due to a loss of coolant accident and, thereby producing conservative experimental data. FIG. 6 is a flow chart showing the operational process of the fibrous debris of test for a nuclear power plant shown in FIG. 1. With FIG. 6, a process for producing fibrous debris for a nuclear power plant is established. First, fibrous debris passed through a strainer is collected in a plurality of strainer bags, and length distribution of the fibrous debris collected by the sample fibrous debris deriving unit 30 is measured S1, S2. The sample fibrous debris deriving unit 30 removes the fibrous debris in the distorted length distribution region and sets the length distribution of fibrous debris within a predetermined critical range to the length distribution of the sample fibrous debris S3. Meanwhile, the fibrous debris producing unit 50 cuts the aged fiber at a predetermined size and then provides the pulverizer with a predetermined weight of the fibers cut to have a uniform size S4, S5. The fibrous debris producing unit 50 sets the previously stored pulverization time and applied voltage according to the type of filter, and the set pulverization time and applied voltage are transferred to the pulverizer to pulverize the fibers of a predetermined weight S6, S7. Accordingly fibrous debris of test is produced. The fibrous debris producing unit 50 judges whether the measured fibrous debris length distribution coincides with the length distribution of the sample fibrous debris, and stores the applied voltage and the pulverization time of the pulverizer in a predetermined memory area by matching with the type of strainer in case coincidence occurs S9, S10. The fibrous debris producing unit 50 determines whether the above-described series of processes has reached the number of times predetermined by the manufacturer or the tester, and ends the present program when the predetermined number of times is reached S11. On the other hand, if it is determined in step S11 that the predetermined number of times has not been reached, the fibrous debris producing unit 50 proceeds to step S7 after changing the applied voltage S12. If the length distribution of the fibrous debris of test does not coincide with the length distribution of the sample fibrous debris, the process proceeds to step S12. The fibrous debris of test produced through the above process is used for the downstream effect test in the core. According to the embodiment of the present invention, fibrous debris of test having the same length distribution as fibrous debris passed through a strainer and collected by a plurality of strainer bags is produced. By carrying out the test for evaluating the influence of debris in the core due to the loss of coolant accident based on the produced fibrous debris for testing, the test reproducibility can be acquired by the fibrous debris of test having a uniform length distribution, thereby producing conservative experimental data. The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied in the form of program instructions, which may be performed via a variety of computing means, and recorded in a computer-readable medium. The computer-readable medium may include program instructions, data files, data structures, and the like, alone or in combination. The program instructions recorded on the medium may be those specially designed and constructed for the present invention or may be available to those skilled in the art of computer software. Examples of computer-readable media include magnetic media such as hard disks, floppy disks and magnetic tape; optical media such as CD-ROMs and DVDs; magneto-optical media such as floptical disks; and hardware devices specifically configured to store and execute program instructions such as ROM, RAM, flash memory, and the like. Examples of program instructions include machine language codes such as those generated by a compiler, as well as high-level language codes that can be executed by a computer using an interpreter or the like. The hardware devices described above may be configured to operate as one or more software modules to perform the operations of the present invention, and vice versa. While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It will be appreciated by those skilled in the art that numerous changes and modifications may be made without departing from the spirit and scope of the invention. It is therefore intended that all such appropriate modifications and variations fall within the scope of the invention. Fibrous debris of test having the uniform length distribution equal to the fibrous debris collected by a plurality of strainer bags while passing through a strainer is produced, and a test for evaluating the influence of debris in the core due to a loss of coolant accident is conducted based on the produced fibrous debris for testing, thereby ensuring reproducibility of a test for evaluating the influence of debris in the core due to a loss of coolant accident and, thereby producing conservative experimental data. Accordingly, there may bring advancements in exactitude of operation, reliability, and operational efficiency in respect to the apparatus and the method for producing fibrous debris for a nuclear power plant. The present invention is industrially applicable since there is not only a good chance of the commercialization or sales of the nuclear power plants to be applied but also practical possibility to carry out clearly.
060841478	abstract	An organic waste decomposition system and method is described having two reaction vessels in tandem, each using superheated steam augmented by oxygen for decomposing a wide variety of organic compounds to reduce both mass and volume. Decomposition takes place quickly when a steam/oxygen mixture is injected into a fluidized bed of ceramic beads. The speed of the fluidizing gas mixture agitates the beads that then help to break up solid wastes, and the oxygen allows some oxidation to offset the thermal requirements of drying, pyrolysis, and steam reforming. Most of the pyrolysis takes place in the first stage, setting up the second stage for completion of pyrolysis and adjustment or gasification of the waste form using co-reactants to change the oxidation state of inorganics and using temperature to partition metallic wastes.
	description	This application is a U.S. national phase of International Application No. PCT/US2018/036388, filed on Jun. 7, 2018, which claims priority to U.S. Provisional Application No. 62/516,508, filed Jun. 7, 2017, both of which are incorporated by reference herein in their entirety. This invention was made with government support under Grant Nos. DE-AC52-07NA27344 and DE-AR0000571, awarded by the Department of Energy (DOE). The government has certain rights in the invention. Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art by inclusion in this section. Nuclear fusion is the process of combining two nuclei. When two nuclei of elements with atomic numbers less than that of iron are fused, energy is released. The release of energy is due to a slight difference in mass between the reactants and the products of the fusion reaction and is governed by ΔE=Δmc2. The release of energy is also dependent upon the attractive strong nuclear force between the reactant nuclei overcoming the repulsive electrostatic force between the reactant nuclei. The fusion reaction requiring the lowest plasma temperature occurs between deuterium (a hydrogen nucleus with one proton and one neutron) and tritium (a hydrogen nucleus having one proton and two neutrons). This reaction yields a helium-4 nucleus and a neutron. One approach for achieving nuclear fusion is to energize a gas containing fusion reactants inside a reactor chamber. The energized gas becomes a plasma via ionization. To achieve conditions with sufficient temperatures and densities for fusion, the plasma needs to be confined. A first aspect of the disclosure is a plasma confinement system that includes an inner electrode having a rounded first end that is disposed on a longitudinal axis of the plasma confinement system and an outer electrode that at least partially surrounds the inner electrode. The outer electrode includes a solid conductive shell and an electrically conductive material disposed on the solid conductive shell and on the longitudinal axis of the plasma confinement system. The electrically conductive material has a melting point within a range of 170° C. to 800° C. at 1 atmosphere of pressure. A second aspect of the disclosure is a method for operating a plasma confinement system. The plasma confinement system includes an inner electrode having a rounded first end that is disposed on a longitudinal axis of the plasma confinement system and an outer electrode that at least partially surrounds the inner electrode. The method includes flowing gas into the plasma confinement system and applying, via a power supply, a voltage between the inner electrode and the outer electrode, thereby converting at least a portion of the gas into a Z-pinch plasma that flows between (i) an electrically conductive material disposed on a solid conductive shell of the outer electrode and on the longitudinal axis of the plasma confinement system and (ii) the rounded first end of the inner electrode. The electrically conductive material has a melting point within a range of 170° C. to 800° C. at 1 atmosphere of pressure. The method also includes moving a first liquid portion of the electrically conductive material out of the plasma confinement system. The first liquid portion of the electrically conductive material is heated via reaction products of the Z-pinch plasma. A third aspect of the disclosure is a plasma confinement system that includes an inner electrode, an intermediate electrode that at least partially surrounds the inner electrode, and an outer electrode that at least partially surrounds the intermediate electrode. The outer electrode includes a solid conductive shell and an electrically conductive material disposed on the solid conductive shell. The electrically conductive material has a melting point within a range of 180° C. to 800° C. at 1 atmosphere of pressure. A fourth aspect of the disclosure is a method for operating a plasma confinement system. The plasma confinement system includes an inner electrode, an intermediate electrode that at least partially surrounds the inner electrode, and an outer electrode that at least partially surrounds the intermediate electrode. The method includes flowing gas into an acceleration region between the inner electrode and the intermediate electrode and applying, via a first power supply, a voltage between the inner electrode and the intermediate electrode, thereby converting at least a portion of the gas into a plasma having a substantially annular cross section, the plasma flowing axially within the acceleration region toward a first end of the inner electrode and a first end of the outer electrode. The method also includes applying, via a second power supply, a voltage between the inner electrode and the outer electrode to establish a Z-pinch plasma that flows between (i) an electrically conductive material disposed on a solid conductive shell of the outer electrode and (ii) the first end of the inner electrode. The electrically conductive material has a melting point within a range of 180° C. to 800° C. at 1 atmosphere of pressure. The method also includes moving a first liquid portion of the electrically conductive material out of the plasma confinement system. The first liquid portion of the electrically conductive material is heated via reaction products of the Z-pinch plasma. When the term “substantially” or “about” is used herein, it is meant that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide. In some examples disclosed herein, “substantially” or “about” means within +/−5% of the recited value. These, as well as other aspects, advantages, and alternatives will become apparent to those of ordinary skill in the art by reading the following detailed description, with reference where appropriate to the accompanying drawings. Further, it should be understood that this summary and other descriptions and figures provided herein are intended to illustrate the invention by way of example only and, as such, that numerous variations are possible. Various embodiments of plasma confinement systems and methods for their use are disclosed herein. The disclosed embodiments, when compared to existing systems and methods, may facilitate increased plasma stability, more robust sheared plasma flow, smaller Z-pinch plasma radii, higher magnetic fields, and/or higher plasma temperature. Some of the disclosed embodiments exhibit independent control of plasma acceleration and plasma compression as well. An additional feature of some of the disclosed embodiments includes one or more electrodes with a liquid electrode material disposed thereon (e.g., disposed on a longitudinal axis of the plasma confinement system). The liquid electrode material can absorb and transfer heat from the plasma discharge, provide neutron shielding, breed additional tritium, provide additional vacuum pumping, and provide a tritium recovery medium. Use of the liquid electrode material can help mitigate problems such as the damage of (solid) electrodes caused by the heat of the plasma discharge. The liquid electrode material can also be circulated within the vacuum chamber (e.g., over a weir wall) such that the liquid electrode material has an azimuthal and/or axial component to its flow within the vacuum chamber. FIG. 1 is a schematic cross-sectional diagram of a plasma confinement system 100. The plasma confinement system 100 includes an inner electrode 102 having a rounded first end 104 that is disposed on a longitudinal axis 106 (e.g., an axis of cylindrical symmetry) of the plasma confinement system 100. The plasma confinement system 100 also includes an outer electrode that at least partially surrounds the inner electrode 102. The outer electrode includes a solid conductive shell 108 and an electrically conductive material 110 disposed on the solid conductive shell 108 and on the longitudinal axis 106 of the plasma confinement system 100. The electrically conductive material 110 has a melting point within a range of 170° C. to 800° C. (e.g., 180° C. to 550° C.) at 1 atmosphere of pressure. In various examples, the electrically conductive material 110 can the take the form of eutectics, alloys, or mixtures of one or more of lithium, lead, or tin. The inner electrode 102 generally takes the form of an electrically conducting shell (e.g., formed of one or more of stainless steel, molybdenum, tungsten, or copper) having a substantially cylindrical body. The inner electrode 102 includes a first end 104 (e.g. a rounded end) and an opposing second end 126 (e.g., a substantially disc-shaped end). The first end 104 could be formed of a carbon-based material such as graphite or carbon fiber, or one or more of stainless steel, molybdenum, tungsten, or copper, for example. In some embodiments, the inner electrode 102 has a coating on its outer surface that includes an electrically conductive material having a melting point within a range of 180° C. to 800° C. (e.g., 180° C. to 550° C.) at 1 atmosphere of pressure. In various examples, the electrically conductive material can the take the form of eutectics, alloys, or mixtures of one or more of lithium, lead, or tin. Alternatively, the electrically conductive material can the take the form of elemental lithium, lead, or tin. The plasma confinement system 100 further includes a feeding mechanism 112 (e.g., an electromechanical system) that is configured to move the inner electrode 102 in or out of the plasma confinement system 100 along the longitudinal axis 106. During operation, the inner electrode 102 may become eroded by plasma discharge and the feeding mechanism 112 can be operated to feed in the inner electrode 102 to maintain the relative spacing between the inner electrode 102 and other components of the plasma confinement system 100. The plasma confinement system 100 further includes a cooling system 114 (e.g., a heat exchanger) that is configured to cool the inner electrode 102 during operation of the plasma confinement system 100. The outer electrode generally takes the form of an electrically conducting (e.g., stainless steel) shell having a substantially cylindrical body. The solid conductive shell 108 of the outer electrode includes a solid conductive outer shell 132 and a solid inner shell 134 (e.g., formed of electrically conductive material or high-resistivity material such as silicon carbide) that is disposed within the solid conductive outer shell 132 and in contact with the solid conductive outer shell 132. More specifically, the solid inner shell 134 includes an axial wall 136 that at least partially encircles the longitudinal axis 106 of the plasma confinement system 100 (e.g., partially encircles the inner electrode 102) and a radial wall 138 that couples the axial wall 136 to the solid conductive outer shell 132. The outer electrode includes a first end 120 and an opposing second end 122. The rounded first end 104 of the inner electrode 102 is between the first end 120 (e.g., a substantially disc-shaped end) of the outer electrode and the second end 122 (e.g., a substantially annular end) of the outer electrode. The radial wall 138 and a first end 120 of the outer electrode form a pool region 140 within the plasma confinement chamber 100. The pool region 140 serves as a reservoir for a substantial amount of the (e.g., liquid) electrically conductive material 110 that is in the plasma confinement chamber 100. As shown, the electrically conductive material 110 can also be circulated over the end 148 of the axial wall 136 by a pump 150 and/or a pump 156 as is discussed in more detail below. The outer electrode (i.e., the solid conductive shell 108 and the electrically conductive material 110) surrounds much of the inner electrode 102. The inner electrode 102 and the outer electrode may be concentric and have radial symmetry with respect to the longitudinal axis 106. The plasma confinement system 100 also includes a heat exchanger 142, a first port 144 configured to guide the electrically conductive material 110 from the heat exchanger 142 into the pool region 140, and a second port 146 configured to guide the electrically conductive material 110 from the pool region 140 to the heat exchanger 142. The heat exchanger 142 is configured to receive, via the second port 146, the electrically conductive material 110 that is heated within the plasma confinement system 100, extract heat from the electrically conductive material 110, and move (e.g., pump) the electrically conductive material 110 back into the pool region 140 via the first port 144 to be heated again by fusion reactions that take place in the plasma confinement system 100. In FIG. 1, the first port 144 is shown above the second port 146, however, in other examples the second port 146 could be above the first port 144. One of skill in the art will recognize that, in various examples, the ports 144 and 146 can have various relative positions. As noted above, the axial wall 136 includes an end 148 that faces the second end 122 of the outer electrode. The plasma confinement system 100 also includes a first pump 150 configured to move the electrically conductive material 110 from the pool region 140 to a region 152 that is outside the axial wall 136 and separated from the pool region 140 by the radial wall 138. The first pump 150 is configured to move the electrically conductive material 110 over the end 148 of the axial wall 136 to a region 154 inside the axial wall 136. The plasma confinement system 100 also includes a second pump 156 configured to move the electrically conductive material 110 from the pool region 140 to the region 152 that is outside the axial wall 136 and separated from the pool region 140 by the radial wall 138. The plasma confinement system 100 also includes a pump 170 (e.g., a turbo-molecular pump) configured to pump air out of the plasma confinement system 100 such that the base pressure within the plasma confinement system 100 is within the range of 10−5 to 10−8 Torr. The plasma confinement system 100 also includes one or more gas ports 116 configured to direct gas (e.g., tritium, deuterium, helium-3, hydrogen, a boron containing gas, or borane) from a gas source 128 (e.g., a pressurized gas tank) into an acceleration region 121 that is radially between the inner electrode 102 and the outer electrode. The acceleration region 121 has a substantially annular cross section defined by the shapes of the inner electrode 102 and the solid conductive shell 108. As shown in FIG. 1, the one or more gas ports 116 are positioned axially between the first end 104 of the inner electrode 102 and the second end 126 of the inner electrode 102. The plasma confinement system 100 also includes a power supply 118 configured to apply a voltage between the inner electrode 102 and the outer electrode (e.g., the solid conductive shell 108). The power supply 118 will generally take the form of a capacitor bank capable of storing up to 500 kJ or up to 3-4 MJ, for example. A positive terminal of the power supply 118 can be coupled to the inner electrode 102 or alternatively to the outer electrode (e.g., the solid conductive shell 108). The plasma confinement system 100 includes an assembly region 124 within the outer electrode between the first end 104 of the inner electrode 102 and the first end 120 of the outer electrode. The plasma confinement system 100 is configured to sustain a Z-pinch plasma within the assembly region 124 as described below. The plasma confinement system 100 also includes an insulator 117 between the second end 122 of the outer electrode (e.g., the solid conductive shell 108) and the inner electrode 102 to maintain electrical isolation between the inner electrode 102 and the outer electrode. The insulator 117 (e.g., a ceramic material) generally has an annular cross section. FIG. 2 is a schematic cross-sectional diagram of a plasma confinement system 200. The plasma confinement system 200 can have any of the features of the plasma confinement system 100, with differences described below. One difference between the plasma confinement system 100 and the plasma confinement system 200 is the presence of the intermediate electrode 205 as part of the plasma confinement system 200 as described below. The plasma confinement system 200 includes an inner electrode 202, an intermediate electrode 205 (e.g., a substantially annular electrode) that at least partially surrounds the inner electrode 202, and an outer electrode that at least partially surrounds the intermediate electrode 205. The outer electrode includes a solid conductive shell 208 and an electrically conductive material 210 disposed on the solid conductive shell 208 (e.g., on the longitudinal axis 206). The electrically conductive material 210 has a melting point within a range of 180° C. to 800° C. (e.g., 180° C. to 550° C.) at 1 atmosphere of pressure. In various examples, the electrically conductive material 210 can the take the form of eutectics, alloys, or mixtures of one or more of lithium, lead, or tin. The inner electrode 202 generally takes the form of an electrically conducting shell (e.g., formed of one or more of stainless steel, molybdenum, tungsten, or copper) having a substantially cylindrical body. The inner electrode 202 includes a first end 204 (e.g. a rounded end) and an opposing second end 226 (e.g., a substantially disc-shaped end). The first end 204 could be formed of a carbon-based material such as graphite or carbon fiber, or one or more of stainless steel, molybdenum, tungsten, or copper, for example. In some embodiments, the inner electrode 202 has a coating on its outer surface that includes an electrically conductive material having a melting point within a range of 180° C. to 800° C. (e.g., 180° C. to 550° C.) at 1 atmosphere of pressure. In various examples, the electrically conductive material can the take the form of eutectics, alloys, or mixtures of one or more of lithium, lead, or tin. The intermediate electrode 205 includes a first end 227 (e.g., a substantially annular end) between the first end 220 of the outer electrode and the second end 222 of the outer electrode. The intermediate electrode 205 also includes an opposing second end 223 that is substantially annular. The plasma confinement system 200 further includes a feeding mechanism 212 (e.g., an electromechanical system) that is configured to move the inner electrode 202 in or out of the plasma confinement system 200 along the longitudinal axis 206. During operation, the inner electrode 202 may become eroded by plasma discharge and the feeding mechanism 212 can be operated to feed in the inner electrode 202 to maintain the relative spacing between the inner electrode 202 and other components of the plasma confinement system 200. The plasma confinement system 200 further includes a cooling system 214 (e.g., a heat exchanger) that is configured to cool the inner electrode 202 during operation of the plasma confinement system 200. The outer electrode generally takes the form of an electrically conducting (e.g., stainless steel) shell having a substantially cylindrical body. The solid conductive shell 208 of the outer electrode includes a solid conductive outer shell 232 and a solid inner shell 234 (e.g., formed of electrically conductive material or high-resistivity material such as silicon carbide) that is disposed within the solid conductive outer shell 232 and in contact with the solid conductive outer shell 232. More specifically, the solid inner shell 234 includes an axial wall 236 that at least partially encircles the longitudinal axis 206 of the plasma confinement system 200 (e.g., partially encircles the inner electrode 202) and a radial wall 238 that couples the axial wall 236 to the solid conductive outer shell 232. The outer electrode includes a first end 220 and an opposing second end 222. The rounded first end 204 of the inner electrode 202 is between the first end 220 (e.g., a substantially disc-shaped end) of the outer electrode and the second end 222 (e.g., a substantially circular or annular end) of the outer electrode. The radial wall 238 and a first end 220 of the outer electrode form a pool region 240 within the plasma confinement chamber 200. The pool region 240 serves as a reservoir for a substantial amount of the (e.g., liquid) electrically conductive material 210 that is in the plasma confinement chamber 200. As shown, the electrically conductive material 210 can also be circulated over the end 248 of the axial wall 236 by a pump 250 and/or a pump 256 as is discussed in more detail below. The outer electrode (i.e., the solid conductive shell 208 and the electrically conductive material 210) surrounds much of the inner electrode 202. The inner electrode 202 and the outer electrode may be concentric and have radial symmetry with respect to the longitudinal axis 206. The plasma confinement system 200 also includes a heat exchanger 242, a first port 244 configured to guide the electrically conductive material 210 from the heat exchanger 242 into the pool region 240, and a second port 246 configured to guide the electrically conductive material 210 from the pool region 240 to the heat exchanger 242. The heat exchanger 242 is configured to receive, via the second port 246, the electrically conductive material 210 that is heated within the plasma confinement system 200, extract heat from the electrically conductive material 210, and move (e.g., pump) the electrically conductive material 210 back into the pool region 240 via the first port 244 to be heated again by fusion reactions that take place in the plasma confinement system 200. In FIG. 2, the first port 244 is shown above the second port 246, however, in other examples the second port 246 could be above the first port 244. One of skill in the art will recognize that, in various examples, the ports 244 and 246 can have various relative positions. As noted above, the axial wall 236 includes an end 248 that faces the second end 222 of the outer electrode. The plasma confinement system 200 also includes a first pump 250 configured to move the electrically conductive material 210 from the pool region 240 to a region 252 that is outside the axial wall 236 and separated from the pool region 240 by the radial wall 238. The first pump 250 is configured to move the electrically conductive material 210 over the end 248 of the axial wall 236 to a region 254 inside the axial wall 236. The plasma confinement system 200 also includes a second pump 256 configured to move the electrically conductive material 210 from the pool region 240 to the region 252 that is outside the axial wall 236 and separated from the pool region 240 by the radial wall 238. The plasma confinement system 200 also includes a pump 270 (e.g., a turbo-molecular pump) configured to pump air out of the plasma confinement system 200 such that the base pressure within the plasma confinement system 200 is within the range of 10−5 to 10−8 Torr. The plasma confinement system 200 also includes one or more gas ports 216 configured to direct gas (e.g., tritium, deuterium, helium-3, hydrogen, a boron containing gas, or borane) from a gas source 228 (e.g., a pressurized gas tank) into an acceleration region 218 that is radially between the inner electrode 202 and the intermediate electrode 205. The acceleration region 218 has a substantially annular cross section defined by the shapes of the inner electrode 202 and the intermediate electrode 205. As shown in FIG. 2, the one or more gas ports 216 are positioned axially between the first end 204 of the inner electrode 202 and the second end 226 of the inner electrode 102. The plasma confinement system 200 also includes a power supply 218 configured to apply a voltage between the inner electrode 102 and the intermediate electrode 205. The power supply 218 will generally take the form of a capacitor bank capable of storing up to 500 kJ or up to 3-4 MJ, for example. A positive terminal of the power supply 218 can be coupled to the inner electrode 102 or alternatively to the intermediate electrode 205. The plasma confinement system 200 also includes a power supply 219 configured to apply a voltage between the inner electrode 202 and the outer electrode (e.g., the solid conductive shell 208). The power supply 219 will generally take the form of a capacitor bank capable of storing up to 500 kJ or up to 3-4 MJ, for example. A positive terminal of the power supply 219 can be coupled to the inner electrode 202 or alternatively to the outer electrode (e.g., the solid conductive shell 208). The plasma confinement system 200 includes an assembly region 224 within the outer electrode between the first end 204 of the inner electrode 202 and the first end 220 of the outer electrode. The plasma confinement system 200 is configured to sustain a Z-pinch plasma within the assembly region 224 as described below. The plasma confinement system 200 also includes an insulator 217 between the second end 223 of the intermediate electrode 205 and the inner electrode 202 to maintain electrical isolation between the inner electrode 202 and the intermediate electrode 205. The insulator 217 (e.g., a ceramic material) generally has an annular cross section. The plasma confinement system 200 also includes an insulator 229 between the solid conductive shell 208 and the intermediate electrode 205 to maintain electrical isolation between the solid conductive shell 208 and the intermediate electrode 205. The insulator 229 (e.g., a ceramic material) generally has an annular cross section. FIG. 3 is a block diagram of a method 300 for operating a plasma confinement system (e.g., the plasma confinement system 100). The plasma confinement system includes an inner electrode having a rounded first end that is disposed on a longitudinal axis of the plasma confinement system and an outer electrode that at least partially surrounds the inner electrode. FIGS. 4-9 illustrate some of the aspects of the method 300 as described below. Although FIGS. 4-9 show the longitudinal axis 106 of the plasma confinement system 100 aligned horizontally, in practice the longitudinal axis 106 generally will be aligned vertically. At block 302, the method 300 includes flowing gas into the plasma confinement system. As shown in FIG. 4 for example, the one or more gas ports 116 can direct gas 310 (e.g., one or more of tritium, deuterium, helium-3, hydrogen, a boron containing gas, or borane) into the acceleration region 121 between the inner electrode 102 and the outer electrode (e.g., the solid conductive shell 108) that substantially surrounds the inner electrode 102. FIG. 4 shows an initial amount of the gas 310 entering the acceleration region 121 and FIG. 5 shows an additional amount of the gas 310 entering the acceleration region 121 thereafter. After flowing the gas 310, a gas pressure adjacent to the one or more gas ports 116 within the acceleration region 121 might be within a range of 1000 to 5800 Torr (e.g., 5450 to 5550 Torr) prior to the voltage between the inner electrode 102 and the outer electrode (e.g., the solid conductive shell 108) being applied via the power supply 118. At block 304, the method 300 includes applying, via a power supply, a voltage between the inner electrode and the outer electrode, thereby converting at least a portion of the gas into a Z-pinch plasma that flows between (i) an electrically conductive material disposed on a solid conductive shell of the outer electrode and on the longitudinal axis of the plasma confinement system and (ii) the rounded first end of the inner electrode. The electrically conductive material has a melting point within a range of 170° C. to 800° C. (e.g., 180° C. to 550° C.) at 1 atmosphere of pressure. Referring to FIGS. 6-9 for example, the power supply 118 can apply a voltage between the inner electrode 102 and the outer electrode (e.g., the solid conductive shell 108), thereby converting at least a portion of the gas 310 into a Z-pinch plasma 318 (see FIGS. 8-9) that flows between (i) the electrically conductive material 110 disposed on the solid conductive shell 108 of the outer electrode and on the longitudinal axis 106 of the plasma confinement system 100 and (ii) the rounded first end 104 of the inner electrode 102. For example, the power supply 118 can apply the voltage between the inner electrode 102 and the solid conductive shell 108, thereby converting at least a portion of the gas 310 into a plasma 316 (see FIGS. 6-9) having a substantially annular cross section. Due to the magnetic field generated by its own current, the plasma 316 may flow axially within the acceleration region 121 toward the first end 104 of the inner electrode 102 and the first end 120 of the outer electrode as shown sequentially in FIGS. 6-9. As shown in FIGS. 8 and 9, when the plasma 316 moves beyond the acceleration region 121, the Z-pinch plasma 318 is established in the assembly region 124 within the outer electrode between (i) the electrically conductive material 110 disposed on the solid conductive shell 108 of the outer electrode and on the longitudinal axis 106 of the plasma confinement system 100 and (ii) the rounded first end 104 of the inner electrode 102. The Z-pinch plasma 318 can exhibit sheared axial flow and have a radius between 0.1 mm and 5 mm, an ion temperature between 900 and 50,000 eV, an electron temperature greater than 500 eV (e.g., up to 50,000 eV), an ion number density greater than 1×1023 ions/m3, an electron number density of greater than 1×1023 electrons/m3, a magnetic field over 8 T, and/or may be stable for at least 10 μs. At block 306, the method 300 includes moving a first liquid portion of the electrically conductive material out of the plasma confinement system. The first liquid portion of the electrically conductive material is heated via reaction products (e.g., neutrons and other energetic particles) of the Z-pinch plasma. The heat exchanger 142 can receive (e.g., pump), via the second port 146, a portion of the electrically conductive material 110 that is heated within the plasma confinement system 100, extract heat from the electrically conductive material 110, and move (e.g., pump) the electrically conductive material 110 back into the pool region 140 via the first port 144 to be heated again by fusion reactions that take place in the plasma confinement system 100. Prior to forming a plasma discharge within the plasma confinement system 100, the electrically conductive material 110 is generally heated (e.g., melted) into a liquid state using a (e.g., electric) heating element disposed within the plasma confinement system 100. The plasma confinement system 100 includes a feeding mechanism 112 (e.g., an electromechanical system) that can move the inner electrode 102 in or out of the plasma confinement system 100 along the longitudinal axis 106. During operation, the inner electrode 102 may become eroded by plasma discharge and the feeding mechanism 112 can be operated to feed in the inner electrode 102 to maintain the relative spacing between the inner electrode 102 and other components of the plasma confinement system 100. In addition, the pumps 150 and 156 can move or circulate the electrically conductive material 110 over the outer electrode (e.g., over the solid conductive shell 108) so that different portions of the electrically conductive material 110 can be used to absorb current and/or heat (e.g., at the longitudinal axis 106) from the Z-pinch plasma 318 over time. During operation of the plasma confinement system 100, much of or all of the electrically conductive material 110 will generally be in a liquid state. In some embodiments, the pumps 150 and 156 move the electrically conductive material 110 such that the electrically conductive material 110 moved over the outer electrode (e.g., over the solid conductive shell 108) is moved in an azimuthal direction (e.g., around the longitudinal axis 106) and/or an axial direction with respect to the longitudinal axis 106 of the plasma confinement system 100. More specifically, the pumps 150 or 156 can move the electrically conductive material 110 from the pool region 140 to a region 152 that is outside the axial wall 136 and separated from the pool region 140 by the radial wall 138. Additionally, the pumps 150 or 156 can move the electrically conductive material 110 over the end 148 of the axial wall 136 to a region 154 inside the axial wall 136, and back toward the pool region 140. In various embodiments, the voltage applied between the inner electrode 102 and the outer electrode (e.g., the solid conductive shell 108) is within a range of 2 kV to 30 kV. The voltage applied between the inner electrode and the outer electrode (e.g., the solid conductive shell 108) can result in a radial electric field within a range of 30 kV/m to 500 kV/m. In some embodiments, the Z-pinch plasma 318 has a radius between 0.1 mm and 5 mm, an ion temperature between 900 and 50,000 eV, and an electron temperature greater than 500 eV (e.g., up to 50,000 eV). The Z-pinch plasma 318 can have an ion number density greater than 1×1023 ions/m3 or an electron number density of greater than 1×1023 electrons/m3, and can exhibit sheared flow with a magnetic field of over 8 T. The Z-pinch plasma 318 can exhibit stability for at least 10 μs. In some embodiments, the reaction products of the Z-pinch plasma 318 include neutrons. As such, during operation of the plasma confinement system 100, neutrons and a portion of the electrically conductive material 110 can be consumed to generate additional tritium fuel for recovery at the heat exchanger 142. The reactive nature of the electrically conductive material 110 can also serve to reduce the base pressure within the plasma confinement system 100 by capturing vapor particles. Some embodiments include controlling a thickness of the electrically conductive material 110 on the solid conductive shell 108 by adjusting a rate at which the heat exchanger 142 moves the electrically conductive material 110 into the pool region 140 from the heat exchanger 142 or by adjusting a rate at which the electrically conductive material 110 moves to the heat exchanger 142 from the pool region 140. Increasing the rate at which the electrically conductive material 110 flows into the pool region 140 will generally increase the thickness of the electrically conductive material 110 on the solid conductive shell 108. Increasing the rate at which the electrically conductive material 110 flows out of the pool region 140 to the heat exchanger 142 will generally decrease the thickness of the electrically conductive material 110 on the solid conductive shell 108. FIG. 10 is a block diagram of a method 1000 for operating a plasma confinement system (e.g., the plasma confinement system 200). The plasma confinement system includes an inner electrode, an intermediate electrode that at least partially surrounds the inner electrode, and an outer electrode that at least partially surrounds the intermediate electrode. FIGS. 11-16 illustrate some of the aspects of the method 1000 as described below. Although FIGS. 11-16 show the longitudinal axis 206 of the plasma confinement system 200 aligned horizontally, in practice the longitudinal axis 206 generally will be aligned vertically At block 1002, the method 1000 includes flowing gas into an acceleration region between the inner electrode and the intermediate electrode. As shown in FIG. 11 for example, the one or more gas ports 216 can direct gas 310 (e.g., one or more of tritium, deuterium, helium-3, hydrogen, a boron containing gas, or borane) into the acceleration region 221 between the inner electrode 202 and the intermediate electrode 205 that partially surrounds the inner electrode 202. FIG. 11 shows an initial amount of the gas 310 entering the acceleration region 221 and FIG. 12 shows an additional amount of the gas 310 entering the acceleration region 221 thereafter. After flowing the gas 310, a gas pressure adjacent to the one or more gas ports 216 within the acceleration region 221 might be within a range of 1000 to 5800 Torr (e.g., 5450 to 5550 Torr) prior to the voltage between the inner electrode 202 and the intermediate electrode 205 being applied via the power supply 218. At block 1004, the method 1000 includes applying, via a first power supply, a voltage between the inner electrode and the intermediate electrode, thereby converting at least a portion of the gas into a plasma having a substantially annular cross section, the plasma flowing axially within the acceleration region toward a first end of the inner electrode and a first end of the outer electrode. Referring to FIGS. 11-14 for example, the power supply 218 can apply a voltage between the inner electrode 202 and the intermediate electrode 205, thereby converting at least a portion of the gas 310 into a plasma 316 having a substantially annular cross section. The plasma 316 can flow axially within the acceleration region 221 toward a first end 204 of the inner electrode 202 and a first end 220 of the outer electrode. Due to the magnetic field generated by its own current, the plasma 316 can flow axially within the acceleration region 121 toward the first end 204 of the inner electrode 202 and the first end 220 of the outer electrode as shown sequentially in FIGS. 11-14. At block 1006, the method 1000 includes applying, via a second power supply, a voltage between the inner electrode and the outer electrode to establish a Z-pinch plasma that flows between (i) an electrically conductive material disposed on a solid conductive shell of the outer electrode and (ii) the first end of the inner electrode. The electrically conductive material has a melting point within a range of 180° C. to 800° C. (e.g., 180° C. to 550° C.) at 1 atmosphere of pressure. Referring to FIGS. 15 and 16 for example, the power supply 219 can apply a voltage between the inner electrode 202 and the outer electrode (e.g., the solid conductive shell 208) to establish the Z-pinch plasma 318 that flows between (i) the electrically conductive material 210 disposed on the solid conductive shell 208 of the outer electrode and (ii) the first end 204 of the inner electrode 202. The electrically conductive material 210 has a melting point within a range of 180° C. to 800° C. (e.g., 180° C. to 550° C.) at 1 atmosphere of pressure. As shown in FIGS. 15 and 16, when the plasma 316 moves beyond the acceleration region 221, the Z-pinch plasma 318 is established in the assembly region 224 within the outer electrode between (i) the electrically conductive material 210 disposed on the solid conductive shell 208 of the outer electrode and on the longitudinal axis 206 of the plasma confinement system 200 and (ii) the rounded first end 204 of the inner electrode 202. The Z-pinch plasma 318 can exhibit sheared axial flow and have a radius between 0.1 mm and 5 mm, an ion temperature between 900 and 50,000 eV, an electron temperature greater than 500 eV (e.g., up to 50,000 eV), an ion number density greater than 1×1023 ions/m3, an electron number density of greater than 1×1023 electrons/m3, a magnetic field over 8 T, and/or may be stable for at least 10 μs. At block 1008, the method 1000 includes moving a first liquid portion of the electrically conductive material out of the plasma confinement system. The first liquid portion of the electrically conductive material is heated via reaction products of the Z-pinch plasma. Referring to FIG. 2 for example, the heat exchanger 242 can receive (e.g., pump), via the second port 246, a portion of the electrically conductive material 210 that is heated within the plasma confinement system 200, extract heat from the electrically conductive material 210, and move (e.g., pump) the electrically conductive material 210 back into the pool region 240 via the first port 244 to be heated again by fusion reactions that take place in the plasma confinement system 200. Prior to forming a plasma discharge within the plasma confinement system 200, the electrically conductive material 210 is generally heated (e.g., melted) into a liquid state using a (e.g., electric) heating element disposed within the plasma confinement system 200. The plasma confinement system 200 includes a feeding mechanism 212 (e.g., an electromechanical system) that can move the inner electrode 202 in or out of the plasma confinement system 200 along the longitudinal axis 206. During operation, the inner electrode 202 may become eroded by plasma discharge and the feeding mechanism 212 can be operated to feed in the inner electrode 202 to maintain the relative spacing between the inner electrode 202 and other components of the plasma confinement system 200. In addition, the pumps 250 and 256 can move or circulate the electrically conductive material 210 over the outer electrode (e.g., over the solid conductive shell 208) so that different portions of the electrically conductive material 210 can be used to absorb current and/or heat (e.g., at the longitudinal axis 206) from the Z-pinch plasma 318 over time. During operation of the plasma confinement system 200, much of or all of the electrically conductive material 210 will generally be in a liquid state. In some embodiments, the pumps 250 and 256 move the electrically conductive material 210 such that the electrically conductive material 210 moved over the outer electrode (e.g., over the solid conductive shell 208) is moved in an azimuthal direction (e.g., into and/or out of the page) and/or an axial direction with respect to the longitudinal axis 206 of the plasma confinement system 100. More specifically, the pumps 250 or 256 can move the electrically conductive material 210 from the pool region 240 to a region 252 that is outside the axial wall 236 and separated from the pool region 240 by the radial wall 238. Additionally, the pumps 250 or 256 can move the electrically conductive material 210 over the end 248 of the axial wall 236 to a region 254 inside the axial wall 236, and back toward the pool region 240. In various embodiments, the voltage applied between the inner electrode 202 and the outer electrode (e.g., the solid conductive shell 108) or between the inner electrode 202 and the intermediate electrode 205 is within a range of 2 kV to 30 kV. The voltage applied can result in electric fields within a range of 30 kV/m to 500 kV/m. In some embodiments, the Z-pinch plasma 318 has a radius between 0.1 mm and 5 mm, an ion temperature between 900 and 50,000 eV, and an electron temperature greater than 500 eV (e.g., up to 50,000 eV). The Z-pinch plasma 318 can have an ion number density greater than 1×1023 ions/m3 or an electron number density of greater than 1×1023 electrons/m3, and can exhibit sheared flow with a magnetic field of over 8 T. The Z-pinch plasma 318 can exhibit stability for at least 10 μs. In some embodiments, the reaction products of the Z-pinch plasma 318 include neutrons. As such, during operation of the plasma confinement system 200, neutrons and a portion of the electrically conductive material 210 can be consumed to generate additional tritium fuel for recovery at the heat exchanger 242. The reactive nature of the electrically conductive material 210 can also serve to reduce the base pressure within the plasma confinement system 200 by capturing vapor particles. Some embodiments include controlling a thickness of the electrically conductive material 210 on the solid conductive shell 208 by adjusting a rate at which the heat exchanger 242 moves the electrically conductive material 210 into the pool region 240 from the heat exchanger 242 or by adjusting a rate at which the electrically conductive material 210 moves to the heat exchanger 242 from the pool region 240. Increasing the rate at which the electrically conductive material 210 flows into the pool region 240 will generally increase the thickness of the electrically conductive material 210 on the solid conductive shell 208. Increasing the rate at which the electrically conductive material 210 flows out of the pool region 240 to the heat exchanger 242 will generally decrease the thickness of the electrically conductive material 210 on the solid conductive shell 208. While various example aspects and example embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various example aspects and example embodiments disclosed herein are for purposes of illustration and are not intended to be limiting, with the true scope and spirit being indicated by the following claims.
	abstract	A probe (1) for electron microscopy is cut from a solid material. A sample surface (3) is configured on the same, which is treated with an ion beam (J) at a predetermined angle of incidence such that the material is ablated from the sample surface (3) by means of etching until the desired observation surface (20) is exposed on the sample (1) in the region of the incidence zone (4) of the ion beam (J), which enables the viewing (12) of the desired region of the sample (1) using an electron microscope. For this purpose, at least two stationary ion beams (J1, J2) are guided onto the sample surface (3) at a predetermined angle (α) in alignment with each other such that the ion beams (J1, J2) at least come in contact with each other on the sample surface (3), or cross each other, and form an incidence zone (4) in that location, and that both the sample (1) and the ion beams (J1, J2) are not moved, and thus are operated in a stationary manner.
	summary
	abstract	A method of generating EUV radiation is described, comprising the steps of:
	description	This is a continuation of U.S. application Ser. No. 13/399,211 filed Feb. 17, 2012, which claims priority to GB 1104548.1 filed Mar. 18, 2011. The prior applications, including the specification, drawings and abstracts are incorporated herein by reference in their entirety. The invention relates to a part-built nuclear reactor module and a method for constructing a nuclear reactor module. In particular, although not exclusively, the invention relates to a transportable part-built nuclear reactor module. Nuclear reactor systems are known which comprise nuclear reactor equipment including a nuclear reactor vessel and a reactor coolant circuit for circulating coolant through the reactor vessel. The nuclear reactor equipment is typically supported by a reinforced concrete support structure which is housed within a containment structure. Such nuclear reactor systems are typically constructed on site. For example, the containment structure may be assembled by either welding together sections of steel plate or by assembling formwork on site into which concrete is poured. Formwork may then be assembled within the containment structure into which concrete is poured to form the concrete support structure for supporting the nuclear reactor equipment. After the concrete support structure has been cleaned and finished the nuclear reactor equipment can be attached and tested. Whilst this is satisfactory, in some circumstances it may be desirable to construct and test at least part of the nuclear reactor system in a factory off-site and then subsequently transport it to site. However, this can be difficult due to the weight of the containment structure housing the concrete support structure and the nuclear reactor equipment. In a broad aspect of the invention there is provided formwork supporting nuclear reactor equipment that can be filled with concrete from the outside of a containment structure through a concrete supply pipe. The formwork may be housed within a containment structure and the supply pipe may extend from the formwork to the outside of the containment structure. This arrangement allows a part-built module to be manufactured off-site in a factory where it can be tested, and subsequently transported by vehicle to site for installation and completion involving concrete pouring. According to an aspect of the invention there is provided a part-built nuclear reactor module, comprising a containment structure housing therein nuclear reactor equipment mounted to formwork; and at least one concrete supply pipe extending from outside of the containment structure to the formwork; wherein the formwork can be filled with concrete through the concrete supply pipe to form a concrete support structure for the nuclear reactor equipment. The formwork may be filled under pressure and may be filled from the bottom. The nuclear reactor equipment may comprise a nuclear reactor vessel and/or a steam generator and/or a pressuriser and/or an accumulator and/or monitoring sensors and/or control circuitry and/or at least part of a coolant circuit. At least part of the formwork is permanent. The formwork may comprise reinforcement bars and/or reinforcement plates. The formwork may define a plurality of voids, each arranged to be filled with concrete through a concrete supply pipe. Each void may be provided with a separate concrete supply pipe. Each concrete supply pipe may extend towards the bottom of the respective void. The formwork may be made from metal such as steel, for example. The module may further comprise at least one removable support that temporarily supports at least some of the nuclear reactor equipment during transportation. The removable support may be a cable, and/or additional framework. The module may further comprise at least one removable brace that temporarily supports at least some of the formwork during transportation. The containment structure may comprise a roof which is supported by at least one concrete supply pipe or vent pipe at least during transportation. There may be provided at least one vent pipe extending from the formwork to the outside of the containment structure for venting dust and/or gases to the atmosphere. The or each concrete supply pipe and the or each vent pipe may be detachable from the module such that after the formwork has been filled with concrete the or each supply pipe can be removed. The pipes may be supplied with drybreak connectors that connect the pipes to the formwork in order to prevent gases and dust escaping from the pipes into the containment structure when the pipes are disconnected. The formwork may comprise at least one void having a structural void and an expansion void disposed above the structural void with a structural support plate having at least one hole therein disposed therebetween. The void may be arranged to be filled with concrete above the structural support plate such that the structural void is filled with structural concrete which can support a load applied to the structural support plate. At least one vent pipe may extend from the expansion void to outside of the containment structure for venting dust and/or gases to the atmosphere. The containment structure may be steel or may be formwork arranged to be filled with concrete on site. The part-built nuclear reactor module may be transportable by vehicle, for example. The invention also concerns a nuclear reactor module constructed from a part-built nuclear reactor module in accordance with claim 1. The nuclear reactor module may be part of a water cooled nuclear reactor installation. According to a further aspect of the invention there is provided a method of constructing a nuclear reactor module, comprising: filling formwork which has nuclear reactor equipment mounted thereto and which is housed within a containment structure with concrete through a concrete supply pipe which extends from outside of the containment structure to the formwork, thereby forming a concrete support structure for the nuclear reactor equipment. The method may further comprise removing at least one removable support that temporarily supports at least some of the nuclear reactor equipment during transportation. The method may further comprise removing at least one removable brace that temporarily supports at least some of the formwork during transportation. The method may further comprise detaching the or each concrete supply pipe after the formwork has been filled with concrete and removing the or each concrete supply pipe from the containment structure. The formwork may comprise at least one void having a structural void and an expansion void disposed above the structural void with a structural support plate having at least one hole therein disposed therebetween. The method may further comprise filling the void with concrete to a level above the structural support plate such that the structural void is filled with structural concrete which can support a load applied to the structural support plate. The invention may comprise any combination of the features and/or limitations referred to herein, except combinations of such features as are mutually exclusive. FIG. 1 shows a nuclear reactor installation which in this embodiment is a nuclear reactor module 10. The reactor module 10 comprises a containment structure 12 which is in the form of a building having a base 13, a generally cylindrical outer wall 14, and a domed-roof 15. In this particular embodiment the containment structure is made from steel plate welded together. However, in other embodiments the containment structure may be formwork for forming a reinforced concrete containment structure, for example. A reinforced concrete support structure 16 is housed within the containment structure 12 and supports nuclear reactor equipment. The nuclear reactor equipment supported by the concrete structure 16 includes a nuclear reactor pressure vessel 18, a steam generator, a pressuriser, an accumulator, monitoring sensors and control circuitry. At least part of a coolant circuit for circulating coolant through the reactor vessel 18 is also provided within the concrete structure. The containment structure 12 is arranged to contain a high internal pressure generated by an escape of coolant from the reactor coolant circuit. In this particular embodiment the coolant is water. The reinforced concrete structure 16 also comprises a refuelling cavity wall 20 which defines a refuelling cavity 22 which is filled with water during refuelling of the reactor vessel 18. The concrete structure 16 also forms numerous tanks, or cavities, within the interior of the structure including a spent fuel pool 21. The concrete also provides radiation shielding from the radiation emitted from the nuclear fuel. Referring now to FIG. 2, the nuclear reactor module 10 is constructed on site from a part-built nuclear reactor module 100 that is manufactured and tested in a factory and transported to site. The part-built nuclear module comprises the containment structure 12 having a base 13, an outer cylindrical wall 14, and a domed roof 15, within which concrete formwork 30 is housed. The nuclear reactor equipment including the nuclear reactor pressure vessel 18, the steam generator, the pressuriser, the accumulator, monitoring sensors and control circuitry is mounted to the formwork 30. At least part of a coolant circuit for circulating coolant through the reactor vessel 18 is also mounted to the formwork 30. The formwork 30 comprises a plurality of steel plates 32 that are welded or otherwise attached together to form a plurality of voids 34 that are arranged to be filled with concrete. The voids 34 may be in fluid communication with one another through passageways so that liquid concrete can flow between them or they may be discrete. Structural reinforcement in the form of reinforcement bars and reinforcement plates (not shown) are disposed within the voids 34 and form part of the formwork 30. A plurality of concrete supply conduits 36, or pipes, extend from outside of the containment structure to the formwork 30. Each concrete supply pipe 36 is in fluid communication with at least one void 34 and each void 34 may be provided with a separate concrete supply pipe 36. In some embodiments the or each concrete supply pipe 36 extends to the bottom of the respective void 34. A vent pipe 38 is also provided that extends from the formwork 30 to the outside of the containment structure. The vent pipe 38 allows dust and gas that can be generated during the concrete filling process to be vented to the atmosphere. It will be appreciated that a plurality of vent pipes 38 may be provided if needed. After the part-built nuclear reactor module 100 has been assembled in a factory the nuclear reactor equipment can be tested. This ensures that the equipment is working correctly before it is transported and installed on site. After testing is complete the part-built nuclear reactor module 100 is transported to site by vehicle for installation. The formwork 30 provides sufficient structural support to the nuclear reactor equipment during transportation. If necessary, additional frameworks, cables, or supports may be provided to further support the nuclear reactor equipment during transportation. These additional supports may be removed once the part-built module 100 has been transported to site. The formwork 30 is also constructed so that it can support itself during transportation. However, if necessary internal bracing or other supports may be provided to support the formwork 30, such as the voids 34. This bracing can be removed after the part-built module 100 has been transported to site. The concrete supply pipes 36 and the vent pipe 38 provide structural support to the containment structure 12 during transportation. In particular, in this embodiment, the vent pipe 38 provides structural support to the domed roof 15 during transportation. This reduces the unsupported length of roof and means that the roof stiffness can be reduced. It should be appreciated that it is not essential that the pipes provide structural support to the containment structure 12 during transport. On site, the part-built module 100 is lifted and set into position by heavy-lifting equipment. The formwork 30 is then filled with concrete from the outside of the containment structure through the plurality of concrete supply pipes 36. The formwork 30 is filled with concrete through the pipes 36 under pressure and from the bottom of the voids 34. This helps to prevent the formation of gaps (or voids) within the concrete. Concrete delivery pipes from a concrete mixer vehicle (not shown) can be attached to the outer end of the concrete supply pipes 36 from the outside of the containment structure to deliver concrete to the formwork 30. The concrete is then left to set for the required period of time after which the concrete support structure 16 is complete. Dust and gas generated during the concrete pouring process is vented to the atmosphere through the vent pipe 38. This prevents the build-up of dust and gas within the clean interior of the containment structure 12. The concrete support structure 16 may then be inspected visually or by x-ray techniques, for example. Although in this embodiment the containment structure 12 is steel, the containment structure 12 may be made from any other suitable material. In one embodiment the containment structure 12 of the part-built module 100 may be formwork that is arranged to be filled with concrete on site. In such an embodiment the concrete supply pipes 36 of the part-built module 100 may extend from outside of the formwork of the containment structure 12 to the formwork 30 housed therein. During transit the supply pipes 36 may support the containment structure 12 formwork. On site, the formwork 30 can be filled with concrete through the concrete supply pipes 36 which then support the containment structure 12 formwork as it is filled with concrete. The concrete supply pipes 36 and/or the vent pipes 38 may be detachable from the part-built module 100. This would allow the pipes 36, 38 to be detached from the formwork 30 and the containment structure 12 after the formwork 30 has been filled with concrete. The pipes 36, 38 could be removed through an access opening in the containment structure 12 or could be removed from the outside of the containment structure 12 through the opening through which it extends. The pipes 36, 38 may include an end cap for closing the opening in the containment structure 12. The ends of the pipes 36, 38 connected to the formwork 30 may be coupled to the formwork 30 using drybreak connectors. This would prevent the leakage of concrete dust or particles into the interior of the containment structure 12 as the pipes 36, 38 are disconnected. The completed concrete support structure 16 formed from filing the formwork 30 with concrete provides the necessary walls 22 and cavities 20, 21 and provides the structural support to the nuclear reactor equipment such as the reactor vessel 18. All or part of the formwork 30 may provide structural support even after the concrete has set. However, all or part of the formwork 30 may not provide any structural support and may either remain in place after the concrete has set or may be removed. Constructing a nuclear reactor module 10 on-site from a part-built nuclear reactor module 100 manufactured and tested in a factory provides a number of advantages. It is important that the interior of the containment structure 12 is kept clean and this is easier to ensure if the part-built module 100 is assembled in a factory. It is also easier and more efficient to test the nuclear reactor equipment in a factory environment. Furthermore, constructing the part-built module 100 in a factory is less expensive and more repeatable when compared to an on-site construction and also allows the use of specialist equipment. Since the part-built module 100 contains formwork 30 that is arranged to be filed with concrete to form a concrete support structure 16 (as opposed to a concrete support structure itself) it is possible to transport the part-built module 100 by vehicle from the factory to the site. On site, the interior of the containment structure 12 is kept clean by filling the formwork 30 through the concrete supply piped 36 from the outside of the containment structure 12. This also allows the sensitive nuclear reactor equipment to be fitted and tested before the concrete support structure 16 is constructed. In order to prevent the formation of cavities within the concrete poured into the formwork 30 it may be necessary to design additional features into the formwork. As shown in FIG. 3, some or all of the voids 34 may comprise a main structural void 40 with a smaller expansion void 42 disposed above it. In this arrangement a structural support plate 44, which is substantially horizontal, is disposed between the structural void 40 and the expansion void 42 and has a plurality of holes therein. These holes allow for the flow of concrete between the structural and expansion voids 40, 42. A concrete supply pipe 36 extends into the bottom of the structural void 40 and a vent pipe extends from the expansion void 36. On site concrete is poured into the void 34 of the formwork 30 through the concrete supply pipe 36. The void 34 is filled with concrete above the level of the structural support plate 44 and therefore partially fills the expansion void 42. Any dust or exhaust gases are vented through the vent pipe 38. The structural support plate 44 is arranged to support a load which it transmits to the structural concrete contained within the structural void 40. Any cavities and gas bubbles are contained within the non-structural concrete contained within the expansion void 42. The expansion void 42 may also contain tools which can vibrate the concrete during pouring and may be used to control the humidity within the void 34. The part-built nuclear reactor module may include any nuclear plant sub-system up to and including the entire plant. The nuclear equipment supported by the formwork may be any component of a nuclear plant or installation requiring support from a concrete structure.
	abstract	A sample processing apparatus includes a probe, a probe mover for moving the probe such that the probe is brought into contact with a part of a sample, an adhering device for adhering the probe to the part of the sample, and an ion beam generator for irradiating the sample with an ion beam to separate the part of the sample from a remaining body of the sample. A temperature controller controls temperatures of the probe and the sample individually to prevent a temperature change of the part of the sample when the probe is bought into contact with the part of the sample and when the sample is irradiated with an ion beam by the ion beam generator.
	abstract	A multilevel MLC includes a first set and a second set of a plurality of pairs of beam blocking leaves arranged adjacent one another. Leaves of each pair in the first set are disposed in an opposed relationship and longitudinally movable relative to each other in a first direction. Leaves of each pair in the second set are disposed in an opposed relationship and longitudinally movable relative to each other in a second direction generally parallel to the first direction. The first and second sets of pairs of leaves are disposed in different planes.
063209241	claims	1. A sub-assembly for a spacer useful in a nuclear fuel bundle for maintaining a matrix of a plurality of nuclear fuel rods passing through the spacer in spaced-apart relation, comprising at least first and second ferrules lying adjacent one another for receiving respective nuclear fuel rods, each ferrule having fuel rod contacting points along one side of the ferrule for abutting a fuel rod within the ferrule, and a substantially I-shaped opening along a side of the ferrule opposite said one side; and a substantially I-shaped spring including a spring body lying in a plane and having opposite horizontal end portions connected by a vertical stem portion, a central portion of each of said horizontal end portions projecting away from said substantially I-shaped opening to one side of said plane and a center portion of said vertical stem projecting into said substantially I-shaped opening to an opposite side of said plane, the spring being disposed between the adjacent ferrules with said vertical stem seated in said opening of said first ferrule with the center portion of the stem adapted to bear against the fuel rod within said first ferrule and maintaining the fuel rod against the fuel rod contacting points of said first ferrule, said horizontal end portions lying with the central portions of each end portion bearing directly against said second ferrule circumferentially between a pair of said fuel rod contacting points of said second ferrule. a peripheral band; a matrix of adjacent ferrules arranged within said band for receiving respective fuel rods; each ferrule having fuel rod contacting points along one side of the ferrule for abutting a fuel rod within the ferrule and a substantially I-shaped opening along a side of the ferrule opposite said one side; and a substantially I-shaped spring including a spring body lying in a plane and having opposite horizontal end portions connected by a vertical stem portion, a central portion of each of said horizontal end portions projecting away from said substantially I-shaped opening to one side of said plane and a center portion of said vertical stem projecting into said substantially I-shaped opening to an opposite side of said plane, said opening being disposed between said adjacent ferrules with said vertical stem seated in said opening of said first ferrule, with the center portion of the stem adapted to bear against the fuel rod within said first ferrule and maintaining the fuel rod against the fuel rod contacting points of aid first ferrule, said horizontal end portions substantially outside said I-shaped opening with the central portions of each end portion bearing directly against said second ferrule circumferentially between a pair of said fuel rod contacting points of said second ferrule. 2. A sub-assembly according to claim 1 wherein said central portion of said spring has a dimple projecting therefrom for engaging the fuel rod within said first ferrule. 3. A sub-assembly according to claim 1 wherein said contacting points comprise indentations along the sides of the ferrules extending the full axial length of the ferrules. 4. The sub-assembly according to claim 1 wherein, within said sub-assembly, said first and second ferrules are similarly oriented. 5. The sub-assembly according to claim 1 wherein each of said first and second ferrules are substantially cylindrical in shape, and wherein said fuel rod contacting points comprise a pair of axial grooves in said ferrule, forming internal, circumferentially spaced, axially extending stops projecting into said ferrules. 6. The sub-assembly of claim 1 wherein said spring includes a pair of T-shaped cutouts, one inverted relative to the other. 7. The sub-assembly of claim 6 wherein said central portions of said horizontal end portions border on respective horizontal portions of said T-shaped cutouts. 8. The sub-assembly of claim 1 wherein said center portion of said vertical stem lies between and adjacent respective vertical portions of said T-shaped cutouts. 9. A spacer for maintaining a matrix of rods in spaced apart relation between upper and lower tie plates, said spacer assembly comprising: 10. The spacer of claim 9 wherein all of said ferrules are similarly oriented relative to each other and to said band.
	summary
	summary
043057837	description	One of the more difficult aspects of high temperature plasma devices is the confinement of the plasma, which is ionized gas. This can be accomplished by the now well-known tokamak device. It has a toroidal containment vessel for containing the gas and the plasma. Twisting magnetic fields are created within the toroidal vessel to confine the plasma and keep it from striking the walls of the toroidal vessel. These fields include toroidal and poloidal components as produced by the flow of electric current. The manner of creating such fields is illustrated conceptually in FIGS. 1 and 2, and a generalized and simplified form of tokamak device is illustrated in FIG. 3. In FIG. 1 is illustrated the means for producing the toroidal magnetic field component. Electrical current is applied over conductors 10 to toroidal field coils 12. The current in these coils links a toroidal space 14 and hence generates a toroidal magnetic field 16 therein, as indicated by the arrows. In FIG. 2 is illustrated the means for producing the principal poloidal magnetic field component that is necessary for stable confinement. In this device, the poloidal field 18, as indicated by the arrows, is induced by toroidal current 20 in the plasma 22. In practice electric current in equilibrium field coils outside to torus generates an additional poloidal magnetic field which modifies the principal poloidal field to control the position of the plasma. As generalized, a conventional tokamak device, as illustrated in FIG. 3, combines the features of FIGS. 1 and 2 to provide a high level of plasma stability. As there illustrated, current from a power source 24 is applied over the conductors 10 to the toroidal field coils 12 which are disposed around a toroidal liner 26 which contains and defines the toroidal space 14 in which the plasma 22 is created. Equilibrium field coils 28 are supplied with electrical current from a source not illustrated to position the plasma 22 within the liner 26. Ohmic heating coils 29, also supplied with electrical current from a source not illustrated, induce current in the plasma 22 to ionize the gas, heat the plasma, and generate the poloidal magnetic field illustrated in FIG. 2. In FIG. 4 is illustrated a preferred form of the invention for producing the toroidal magnetic field. It is thus a form of the device shown in stylized form in FIG. 1. In this preferred embodiment of the present invention, a pressure vessel 30 forms a reservoir filled with liquid metal 32. A toroidal liner 34 is supported within the liquid metal 32 by struts 36 extending to the vessel 30. The pressure vessel 30 is formed of material, such as stainless steel, capable of withstanding relatively high internal pressure while not being attacked by the environment, notably the liquid metal 32. While various other metals are effective for certain purposes, liquid lithium is preferred for the liquid metal 32, particularly for deuterium-tritium plasma devices, for lithium is suitable for moderating resultant neutrons and acts to breed tritium fuel by reaction with the neutrons: EQU .sub.3 Li.sup.6 30 .sub.0 n.sup.1 .fwdarw..sub.1 H.sup.3 +.sub.2 He.sup.4. The liquid metal also acts as a coolant, being circulated by a pump 38 through a heat exchanger 40 by way of conduits 42. The toroidal liner 34 is preferably formed of electrically insulating material and may have equilibrium field coils 44 and ohmic heating coils 46 embedded therein to provide an appropriate poloidal magnetic field and appropriate ohmic heating in the usual fashion. Alternatively, these coils 44 and 46 may be supported in the liquid metal 32. The toroidal liner 34 defines a toroidal space 48 in which gas is confined for producing plasma. The liner 34 separates the liquid metal 32 from the toroidal space 48 and thus forms a bubble of gas in a pool of liquid. The ohmic heating coils 46 are energized in a conventional manner to ionize the gas and produce the plasma. The plasma is positioned by the action of the poloidal equilibrium magnetic field and is stabilized by a toroidal field produced by current passed through the liquid metal over a conductive path 49 linking the toroidal space 48. Such current is passed through the liquid metal 32 between conductive feed plates 50 and 52, the feed plates 50 and 52 having an insulator 54 interposed therebetween to cause the current flow to link the space 48. Current is supplied to the conductive plates from a power supply 56. To confine and heat the plasma well, it is desirable to provide a high toroidal magnetic field. This requires extremely large electrical currents through the liquid metal, which is a good electrical conductor. It is difficult to provide such large electrical currents at low impedance efficiently. Furthermore, in order to provide uniformity, it is desirable that the currents be generated in a manner evenly distributed azimuthally around the torus. Specific preferred power supplies 56 for so generating the current are shown in FIGS. 5, 6 and 7. The power supply illustrated in FIG. 5 is an equatorial homopolar generator 58. A homopolar generator operates on the same principle as a conventional generator of electrical current, namely that when a conductor is moved across a magnetic field, current is generated orthogonally to both the direction of motion and the direction of the magnetic field. The difference is that in a homopolar generator the magnetic field does not vary along the direction of conductor motion. Homopolar generators are characteristically of much lower impedance than conventional generators and produce direct current. In FIG. 5 the homopolar generator 58 is shown in transverse section through the major axis of the toroidal liner 34. The generator 58 is circularly symmetrical about that axis and is mounted equatorially of the toroidal space 48. The generator 58 includes a homopolar rotor 60 mounted in any convenient fashion for rotation about the major axis of the liner 34. Upper and lower field exciting coils 62 and 64, which are preferably superconductive, are driven by a current supply, not shown, to produce a magnetic field indicated by B flowing transversely of the rotor 60. When the rotor 60 is rotated about its axis (into the plane of the drawing as shown in FIG. 5), direct current is induced in the feed plates 50 and 52, flowing through the plate 50 to and through the liquid metal 32 linking the toroidal space 48, and thence back through the plate 52 to the generator 58. Because the tokamak device and the homopolar generator 58 are circularly symmetrical, the current is evenly distributed azimuthally around the torus, hence producing a uniform toroidal field. Brushes 66 connect the plates 50 and 52 to the respective poles of the rotor 60. Because the currents are very great, it is desirable to use brushes of particularly good conductivity. Such brushes may be liquid metal brushes, as in the form of pools of mercury. The rotor 60 may be driven in any conventional manner, as through gears. Preferably, however, it is driven by a hydraulic turbine, turbine blades 67 being fastened on the outer surface of the rotor. Alternatively, the rotor 60 may be driven as the rotor of an induction motor by means of the rotating magnetic field of an adjacent stator. In FIGS. 6 and 7 is shown a related power supply in the form of magnetohydrodynamic (MHD) generator 68 which is much like the homopolar generator but uses flowing liquid metal instead of the rotating solid rotor. In FIG. 6 and MHD generator 68 is shown in section through the major axis of the toroidal liner 34. The generator 68 may be generally circularly symmetrical, like the homopolar generator 58, but it is preferably comprised of a number of separate sections each beginning and ending as shown in FIG. 7. Liquid metal is circulated by a driving means 69 through a conduit or conduits 70 defined by the feed plates 50 and 52 and by insulating wall members 72. The fluid is introduced into the conduits 70 through respective curved inlet conduits 78 and leaves through respective curved outlet conduits 80. The inlet and outlet conduits 78 and 80 are made from electrically insulating materials to reduce eddy current losses. The liquid is conveniently driven by a driving means 69 formed of a high pressure pneumatic accumulator with throttle valves for power modulation for pulsed operation, or by pumps for steady operation. The exciting field is provided by upper and lower exciting coils 74 and 76, just as in the homopolar generator, to produce a radially transverse magnetic field B. Movement of the conductive liquid metal through the conduit or conduits 70 then generates direct current through the feed plate 50, thence through the liquid metal 32 in a path linking the toroidal space 48, and back through the feed plate 52. The result is the same as with the homopolar generator 58. In operation of the tokamak system of the present invention, plasma is created in the toroidal space 48 by introducing appropriate gas filling therein and applying current in a known manner to the ohmic heating coils 46. This may be in a known back-bias to zero mode. The plasma may then be maintained in position in a known manner by applying appropriate current to the equilibrium field coils 48. The present invention permits the application of very high currents in excess of, for example, 10.sup.7 A) through the liquid metal 32 around the toroidal space 48 and hence a relatively high toroidal magnetic field so as to confine the plasma. At the same time, because the conductor is liquid, internal stresses are automatically alleviated, being transferred to the pressure vessel 30, which is made of structural material and is preferably spherical for maximum strength. The power supply 56 must be a low impedance, high power source, preferably providing current to the liquid metal 32 substantially evenly distributed azimuthally around the major axis of the toroidal space. While preferred embodiments of the invention have been shown and described, various modifications may be made therein within the scope of the invention. For example, the containment vessel 30 may take other shapes. The ohmic heating coils 46 and the equilibrium coils 44 may be disposed differently and may be driven in a number of known ways. The power supply 56 may take other forms. Other materials may be used. As the liquid metal 32 is subject to large magnetohydrodynamic convective cells means, such as baffles, may be used to reduce the size of the cells, when necessary or desirable; however, the poloidal field provides some stabilization and damping. It should also be noted that details of well-known components of tokamak devices have been omitted from the drawings in order that the essential parts of the invention may be more easily shown and understood. The present invention provides a relatively high toroidal field with a relatively small overall device. The smaller size of the device may result in lower cost, and the higher field confines the plasma to a smaller volume, increasing the interaction between the plasma particles.
046577319	summary	The present invention relates to a method for removing cesium from an aqueous liquid, a method for purifying the reactor coolant used in a boiling water nuclear reactor or in the primary circuit of a pressurized water nuclear reactor and to a resin bed containing a mixture of an anion exchange resin and cation exchange resin useful in said purification. In the operation of a pressurized water reactor for the production of power, large amounts of water (commonly referred to as a "reactor coolant") are circulated through a loop (conventionally referred to as the "primary loop" or "circuit") containing the reactor and a heat-exchanger boiler or steam generator. The reactor coolant transfers heat gained from the reactor core to the heat-exchanger boiler where the high temperature, reactor coolant which conventionally flows through the tubes of the boiler generates steam from feed water flowing through the shell side of the boiler. Conventionally, the generated steam is fed to a turbine generator for the production of electrical power. Throughout its circulation through the primary circuit, the reactor coolant is maintained at a sufficiently high pressure to prevent boiling, i.e., the reactor coolant is maintained as a liquid. In the described operation of a pressurized water reactor, the reactor coolant, or at least a portion thereof, is continuously purified to remove or reduce the radioactive isotopes and other impurities contained therein. In general, to remove the undesirable ionic components from the reactor coolant, the coolant is contacted with both an anion and cation exchange resin. Although the reactor coolant can sequentually be contacted with the one resin type and thereafter with the other resin type, the liquid is more conventionally contacted with a resin bed containing both the anion and cation exchange resins, i.e., a mixed resin bed. The cation exchange resin of the mixed resin bed remove the cationic impurities, including the various cationic radioactive isotopes, from the reactor coolant. Representative of such radioactive isotopes include the isotopes of cesium, iodine, strontium, antimony, lithium-7, (formed by neutron activation of boron, which is added to control excessive neutrons), and radioactive corrosion products such as the isotopes of cobalt, manganese, chromium and iron. The capacity of the cation exchange resin to remove cesium from the reactor coolant is particularly important due to the high concentration of radioactive cesium isotopes in the coolant. Conventionally, the cation exchange resin is a macroporous, strong acid cation exchange resin prepared from styrene and up to about 12 weight percent divinylbenzene, said weight percent being based on the total styrene and divinylbenzene. In the described ion exchange operation, the capacity of the cation exchange resin to remove the radioactive isotopes from the reactor coolant decreases with time. In a conventional operation, the resin will be employed until the resin can no longer remove the desired amounts of radioactive isotopes from the coolant, at which time, the decontamination factor (DF) (i.e. the ratio of (1) the concentration of radioactive isotopes in the reactor coolant prior to treatment and (2) the concentration of radioactive isotopes following treatment with the ion exchange resin) is reduced to an undesirably low number. Unfortunately, upon reaching an undesirably low DF, the regeneration of the exhausted resin is not practical since the resin cannot effectively be regenerated without creating radioactive waste water. Moreover, due to the presence of radioactive isotopes in the resin, disposal of the resin requires relatively complex and expensive techniques. Therefore, improvements in the described purification process which extend the operating life of the mixed resin bed are highly desirable. Such improvements are also desirable in other operations involving the removal of radioactive cesium isotopes from an aqueous liquid such as the treatment of water employed in the storage of a nuclear fuel. Accordingly, in one aspect, the present invention is a method for removing cesium isotopes from an aqueous liquid. The method comprises contacting the cesium containing aqueous liquid with a strong acid cation exchange resin of a highly cross-linked, macroporous copolymer derived from a monovinylidene aromatic and a cross-linking monomer copolymerizable therewith. The cross-linking monomer is employed in an amount of at least 12 mole percent based on the total weight of the monovinylidene aromatic and a cross-linking monomer. The highly cross-linked, cation exchange resin exhibits an unexpectedly high capacity for removing cesium isotopes from an aqueous liquid. For example, a strong acid resin derived from a copolymer of styrene and 12.5 mole percent divinylbenzene (i.e., 16 weight percent divinylbenzene) exhibits a significantly better performance than a strong acid resin prepared using 9 mole percent (i.e., 12 weight percent) divinylbenzene. Therefore, the method of the present invention is useful in treating the water used in the storage of spent nuclear fuel. In a particularly preferred embodiment, the present invention is a method for purifying the reactor coolant of a pressurized water or boiling water reactor. Said method, which is particularly advantageously employed in purifying the reactor coolant in the primary circuit of a pressurized water reactor, comprises contacting at least a portion of the reactor coolant with a strong base anion exchange resin and the strong acid cation exchange resin derived from a highly cross-linked, macroporous copolymer of a monovinylidene aromatic and a cross-linking monomer copolymerizable therewith. Although the reactor coolant can sequentially be contacted with one resin type and thereafter with the second resin type, the contact is preferably conducted using a resin bed comprising a mixture of the cation and anion exchange resins. Surprisingly, by the method of the present invention, the highly cross-linked, strong acid resin can be employed to remove the radioactive isotopes (including cesium, strontium and antimony) from the reactor coolant for unexpectedly long periods without the need to remove and dispose of the resin. Such an unexpectedly better performance is demonstrated by reference to the FIGURE. Specificially, the FIGURE is a graphically representation plotting the concentration of cesium in a reactor coolant of a pressurized water reactor following treatment with a mixed resin bed containing a cation exchange resin, as a percentage of the concentration of cesium in the reactor coolant prior to treatment, versus the number of bed volumes of the reactor coolant, based on the volume of the cation resin in the mixed resin bed, having been treated by the resin. Curve A represents the exceptional performance of a mixed resin bed containing a macroporous, strong acid resin of a copolymer derived from 80 weight percent styrene and 20 weight percent divinylbenzene. Curve B represents the performance of a mixed bed containing a macroporous, strong acid resin of a copolymer derived from 88 weight percent styrene and 12 weight percent divinylbenzene. Curve C represents the performance of a mixed resin bed containing a gel type strong acid resin of a copolymer derived from 92 weight percent styrene and 8 weight percent divinylbenzene. Due to this superior performance of the macroporous, strong acid cation exchange resin derived from 20 weight percent of divinylbenzene as the cross-linking monomer, as compared to the macroporous, strong acid cation exchange resin derived from 12 percent divinylbenzene, the period between shut downs for the removal of the resin from the column upon its exhaustion is extended, thereby reducing the costs associated with the disposal of the exhausted resin. In yet another aspect, the present invention is a resin bed comprising a strong base anion exchange resin and the strong acid cation exchange resin derived from the highly cross-linked, macroporous copolymer of a monovinylidene aromatic and a cross-linking monomer. The strong acid cation exchange resins useful in the method of the present invention are advantageously macroporous, addition copolymerization productis of a monovinylidene aromatic and a cross-linking monomer; typically, a polyethylenically unsaturated monomer. Monovinylidene aromatics and cross-linking monomers copolymerizable therewith are well-known in the art and reference is made thereto for the purposes of this invention. The preferred monovinylidene aromatics include styrene, halo-substituted styrenes, e.g., bromostyrene and chlorostyrene, and vinyl naphthalene. Although monoalkyl-substituted styrenes such as vinlyl toluene or ethyl vinylbenzene can also be employed, especially if the substituant groups are not in a para position with respect to each other, said monoalkyl styrenes are more advantageously empolyed in combination with styrene. In the practice of this invention, styrene is the most preferred monovinylidene aromatic. Preferred cross-linking agents are the polyvinylidene aromatics such as divinylbenzene, divinyl toluene, divinyl xylene, divinyl napthalene, divinyl sulfone, trivinylbenzene, divinyldiphenyl ether, divinyldiphenyl sulfone and isopropenyl vinylbenzene; divinyl sulfide; ethylene glycol dimethacrylate and the like. Of such cross-linking monomers the divinylidene aromatic compounds, particularly divinylbenzene and divinyldiphenyl sulfone, most especially divinylbenzene, are preferably employed herein. The highly cross-linked, copolymer is derived from at least 12 mole percent of the cross-linking monomer and less than 88 mole percent of the monovinylidene aromatic, said mole percents being based on the total moles of the cross-linking agent and the monovinylidene aromatic. Typically, this corresponds to a copolymer derived from at least 16 weight percent of the cross-linking monomer and less than 84 weight percent of the monovinylidene aromatic, said weight percents being based on the weight of the cross-linking monomer and monovinylidene aromatic. Advantageously, the highly cross-linked copolymer is derived from less than 35 weight percent of the cross-linking monomer. Preferably, the copolymer is composed, in polymerized form, of from 18 to 28, more preferably 18 to 25, weight percent of the cross-linking monomer and from 72 to 82, more preferably from 75 to 82, weight percent of the monomer of the monovinylidene aromatic. Most preferably, the copolymer is composed of 18 to 24 weight percent divinylbenzene and from 76 to 82 weight percent styrene. The highly cross-linked, macroporous copolymers are prepared using methods employed for copolymerizing a monvinylidene aromatic and cross-linking monomer in macroporous (macrorecticular) form. Such methods (including the catalyst, polymerization medium and pore forming materials) are well-known in the art and reference is made thereto for the purposes of this invention. Representative of such methods are disclosed in U.S. Pat. Nos. 3,173,892; 3,549,562; 3,637,535 and 4,104,209. Although, the highly cross-linked, macroporous copolymer can be prepared in granular form, advantageously, the copolymer is prepared in the form of spheroidal beads, preferably with a volume average particle diameter of from 0.1 to 1.4 mm, with an average diameter between 0.3 and 1.2 being most preferred. Strong acid resins are prepared from the highly cross-linked, macroporous copolymers using techniques well-known in the art for converting cross-linked copolymers of a monovinylidene aromatic to a strong acid cation exchange resin. Illustrative of such methods for preparing strong acid resins are U.S. Pat. Nos. 3,266,007; 2,500,149; 2,631,127; 2,664,801; 2,764,564 and Ion Exchange by F. Halfferich, published in 1962 by McGraw-Hill Book Company, New York (all of which are hereby incorporated by reference). In general, the strong acid resins are prepared by sulfonating the copolymer. While the sulfonation may be conducted neat, generally, the copolymers are swollen using a suitable swelling agent such as a sulfonation resistant chlorinated hydrocarbon (e.g., chlorobenzene or tetrachloroethylene) or an aliphatic or aromatic hydrocarbon (e.g., toluene or xylene) and the swollen copolymer reacted with a sulfonating agent such as sulfuric or chlorosulfonic acid or sulfur trioxide. Preferably, an excess amount of the sulfonating agent, e.g., from about 2 to about 7 times the weight of the copolymer, is employed and the sulfonation is conducted at a temperature from 50.degree. C. to 200.degree. C. Although the highly cross-linked, strong acid resin can suitably be employed in any of a variety of cationic forms, e.g., H.sup.+, NH.sub.4.sup.+, Na.sup.+ or the like, to remove cesium or other radioactive isotopes from an aqueous liquid; the H.sup.+ form of the resin generally results in the most effective operation. Specifically, the H.sup.+ form of the cation resin possesses the most desirable combination of resin capacity (i.e., the total amounts of cesium and/or other radioactive isotopes which can be removed from the solution by the resin) and resin kinetics (i.e., the rate at which the cation exchange resin can abstract cesium or other radioactive isotopes from solution). In general, following sulfonation, substantially all the sulfonated copolymer will have an H.sup.+ form. A preferred highly cross-linked, macroporous, strong acid resin is sold as XZ-86275 by The Dow Chemical Company. Cesium, and optionally, other radioactive cations are removed from an aqueous liquid by contacting the cesium containing aqueous liquid with the highly cross-linked, macroporous, strong acid resin at conditions sufficient to remove the desired amounts of cesium and other radioactive isotopes from the aqueous liquid. As used herein, the term "aqueous liquid" refers to water (including aqueous liquids such as alkaline or acidic aqueous solutions, e.g., an aqueous solution of calcium or sodium hydroxide, or aqueous salt solutions) or a mixture of water and a water-miscible liquid such as a lower alkanol, e.g., methanol, ethanol or propanol; a lower ketone, e.g., acetone or methyl ethyl ketone; an ether, e.g., diethyl ether or diethylene glycol methylether and the like. Although batch-type techniques can be employed in treating the cesium containing aqueous liquid, in general, continuous type, ion exchange techniques wherein the cesium containing aqueous liquid is continuously flowed, either upwardly or downwardly, preferably downwardly, through a column containing the highly cross-linked, macroporous, strong acid resin are preferred. In general, the contact of the strong acid resin with the cesium containing aqueous liquid, is conducted at ambient temperatures with a flow rate of the cesium containing aqueous liquid being from 1 to 100 volumes of the liquid per each volume of the highly cross-linked, macroporous, strong acid resin (i.e., from 1 to 100 bed volumes (BV) of the cesium containing aqueous liquid) per hour. The specific conditions for such contact are dependent on a variety of factors including the specific aqueous liquid and the concentration of cesium (and other radioactive) isotopes in the aqueous liquid; the specific strong acid resin employed and the amount of cross-linking monomer employed in its preparation; the desired amounts of cesium (and other radioactive) isotopes to be removed from the aqueous liquid and the like. As an example, in the treatment of water employed in the storage of the nuclear fuel of cesium and other radioactive isotopes, the cesium containing liquid is advantageously flowed through a bed of the highly cross-linked, macroporous strong acid resin at a rate generally from 10 to 70, preferably from 15 to 40, BV/hour. Alternatively, in a process for purifying the reactor coolant of a pressurized water or boiling water reactor, the reactor coolant is advantageously flowed through the highly cross-linked, macroporous, strong acid resin and a strong base, anion exchange resin (herein generally referred to as "strong base resin"). The strong base resin is suitably a strong base resin of the gel or macroporous type, which resins are well-known in the art. Conventionally, the strong base resin is a cross-linked copolymer of a monovinylidene aromatic and a cross-linking monomer copolymerizable therewith which polymer bears quarternary ammonium groups. In general, these resins are prepared by copolymerizing the monovinylidene aromatic and cross-linking agent, halomethylating the cross-linked addition copolymer and thereafter quarternizing the halomethylated resin using techniques well-known in the art, with reference being made thereto for the purposes of this invention. For example, as illustrated by U.S. Pat. Nos. 2,642,417; 2,960,480; 2,597,492, 2,597,493; 3,311,602 and 2,616,877, halomethylation of the cross-linked copolymer can be conducted by contacting the cross-linked addition copolymer with a halomethylating agent in the presence of a Friedel-Crafts catalyst. Alternatively, the halomethylated cross-linked copolymer can be prepared by copolymerizing a polymerizable, halomethylated monovinylidene aromatic such as vinyl benzylchloride with a cross-linking monomer using techniques such as described in U.S. Pat. No. 2,992,544. Strong base resins are subsequently prepared from the halomethylated copolymer by heating, with reflux, a mixture of the halomethylated copolymer with at least a stoichoimetric amount of a tertiary amine such as trimethyl amine, dimethylisopropanol amine and the like at temperatures sufficient to react the amine with the benzylic halogen atom. Alternatively, the strong base resin can be the cross-linked addition polymerization product of a suitable nitrogen-containing compound. For example, the addition copolymerization product of vinyl pyridene or vinyl methylpyridene, a cross-linking agent such as divinylbenzene, divinyl ketone or methylene bisacrylamide and, optionally, a monovinylidene aromatic such as styrene can be converted to a quaternary ammonium form. A strong base resin can also be prepared by the addition polymerization of a diallyldimethylammonium chloride which polymerization may also include a cross-linking agent such as divinyl ketone. The preferred strong base resins are quaternary ammonium derivatives of a gel-type copolymer of styrene and divinylbenzene. Although various anionic forms of the strong base resin can be employed, the strong base resin is preferably in OH.sup.- form, with a residual chloride anion content of less than about 3, more preferably less than 1, percent based on the total capacity of the resin. Advantageously, the strong base resins are prepared in the form of spheroidal beads having a number average particle size of 0.1 to 1.4 mm, preferably from 0.3 to 1 mm. Although, in the purification of the reactor coolant, the coolant can be sequentially contacted with first one type of resin followed by contact with the second type of resin, the coolant is more advantageously contacted with a resin bed comprising a mixture of the highly cross-linked, macroporous, strong acid resin and the strong base resin. In general, the mixed resin bed will comprise from 0.8 to 1.2, preferably from 0.9 to 1.1, equivalents of the strong base resin (i.e., equivalents of anionic exchange sites) for each equivalent of the highly cross-linked, macroporous, strong acid resin contained in the mixed resin bed. This typically corresponds with a resin bed comprising from 30 to 50 volume percent of the strong base resin and from 50 to 70 volume percent of the strong acid resin, said volume percents being based on the total volume of the resin employed in preparing the mixed resin bed. Most preferably, the mixed resin bed comprises equal amounts, on an equivalent basis, of the strong base resin and the highly cross-linked, macroporous, strong acid resin. The contact of the reactor coolant with the mixed resin bed is advantageously conducted by continuously flowing the coolant through the mixed resin bed at a rate from 10 to 90, preferably from 30 to 80, more preferably from 40 to 60, BV per hour, said rate being based on the volume of the highly cross-linked, macroporous, cation exchange resin in the mixed resin bed. Following ion exchange resin treatment, the purified reactor coolant can be recirculated directly to the reactor. Alternatively, the reactor coolant may subsequently be treated with an additional bed comprising a strong acid cation exchange resin. Such additional, cation exchange resin bed is particularly advantageously employed in operations where the reactor coolant may contain excess lithium or cesium isotopes or to prevent leakage of radioactive cations back to the reactor. The following example is included to demonstrate the advantages of the present invention and should not be construed to limit its scope. All percentages are weight percentages unless otherwise indicated.
	summary
	abstract	A stud enclosure for protecting a stud extending upwardly from a nuclear reactor pressure vessel (RPV) flange has a cylindrical can with a capped end and an open end. The capped end has an axially extending hole with a screw extending therein for fastening the stud enclosure to the stud. A seal ring is disposed adjacent the open end of the cylindrical can for sealing the ring on the RPV flange. A gas valve is disposed in the capped end of the cylindrical can for pressurizing the interior portion of the can with air.
055132340	claims	1. An apparatus for supporting multiple transversely disposed nuclear reactor fuel channel pressure tubes, comprising: a) a first tube shaped portion having a length; b) a second tube shaped portion having a length; c) a web connecting said first tube shaped portion to said second tube shaped portion; and d) a plurality of support pads disposed internally to said first tube shaped portion and said second tube shaped portion, said plurality of support pads extending said length of said first tube shaped portion and said length of said second tube shaped portion, said plurality of support pads forming an air space between each fuel channel pressure tube and said first tube shaped portion and said second tube shaped portion, said first tube shaped portion and said second tube shaped portion defining and functioning as an outer calandria tube for said each fuel pressure tube so that said each fuel channel pressure tube is protected against sags caused by gravity and ultimate cracks and said air space providing conduits for coolant. a) a hollow outer shell having a length; b) a sideward partitioning wall disposed internal to said hollow outer shell and having a length; c) an upward partitioning wail disposed internal to said hollow outer shell and having a length, said upward partitioning wall forming in conjunction with said sideward partitioning wall a criss cross configuration, said criss cross configuration and said hollow outer shell defining a plurality of closed chambers; and d) a plurality of support pads disposed internally to said hollow outer shell, said plurality of support pads extending said length of said hollow outer shell and said length of said sideward partitioning wall and said length of said upward partitioning wall, said plurality of support pads supporting a fuel channel pressure tube contained within each of said plurality of closed chambers and forming an air space between each said fuel channel pressure tube and said outer shell and said criss cross configuration of said sideward partitioning wall and said upward partitioning wall, said outer shell in conjunction with said upward partitioning wail and said sideward partitioning wall defining and functioning as an outer calandria tube for said each said fuel channel pressure tube so that said each said fuel channel pressure tube is protected against sags caused by gravity and ultimate cracks and said air space providing conduits for coolant. 2. The apparatus as defined in claim 1, wherein said first tube shaped portion, said second tube shaped portion, said plurality of support pads, and said web are integrally formed. 3. The apparatus as defined in claim 1, wherein said first tube shaped portion, said second tube shaped portion, and said web are integrally formed. 4. The apparatus as defined in claim 1, wherein said plurality of support pads include side support pads and web support pads. 5. The apparatus as defined in claim 4, wherein said web and said web support pads are integrally formed. 6. The apparatus as defined in claim 4, wherein said first tube shaped portion, said second tube shaped portion, and said web support pads are integrally formed.- 7. The apparatus as defined in claim 1, wherein said first tube shaped portion, said second tube shaped portion, said plurality of support pads, and said web are manufactured from metal. 8. The apparatus as defined in claim 1, wherein said first tube shaped portion, said second tube shaped portion, said plurality of support pads, and said web are manufactured from fiberglass. 9. The apparatus as defined in claim 1, wherein said first tube shaped portion, said second tube shaped portion, said plurality of support pads, and said web are manufactured from plastic. 10. An apparatus for supporting multiple transversely disposed nuclear reactor fuel channel pressure tubes, comprising: 11. The apparatus as defined in claim 10, wherein said hollow outer shell, said sideward partitioning wall, said upward partitioning wall, and said plurality of support pads are integrally formed. 12. The apparatus as defined in claim 10, wherein said hollow outer shell, said sideward partitioning wall, and said upward partitioning wall are integrally formed. 13. The apparatus as defined in claim 10, wherein said plurality of support pads include hollow outer shell pads, hollow outer shell corner pads, sideward partitioning wall pads, and upward partitioning wall pads. 14. The apparatus as defined in claim 13, wherein said hollow outer shell, said hollow outer shell pads, and said hollow outer shell corner pads are integrally formed. 15. The apparatus as defined in claim 13, wherein said sideward partitioning wall and said sideward partitioning wall pads are integrally formed. 16. The apparatus as defined in claim 13, wherein said upward partitioning wall and said upward partitioning wall pads ,are integrally formed. 17. The apparatus as defined in claim 10, wherein said hollow outer shell, said sideward partitioning wall, said upward partitioning wall, and said plurality of support pads are manufactured from metal. 18. The apparatus as defined in claim 10, wherein said hollow outer shell, said sideward partitioning wall, said upward partitioning wall, and said plurality of support pads are manufactured from plastic. 19. The apparatus as defined in claim 10, wherein said hollow outer shell, said sideward partitioning wall, said upward partitioning wall, and said plurality of support pads are manufactured from fiberglass.
	description	The present invention relates to optical storage media having a plurality of writeable and/or readable data storage layers, optical read/write apparatus using such media, and optical read/write method using such media. Recent years have seen on-going development of optical read/write apparatus capable of writing a large amount of data, like video data in digital format, and randomly accessing such data. Also, various attempts are being made to increase the storage density of optical disks used as storage media in such optical read/write apparatus. In optical read/write apparatus, attempts are being made to increase storage density by means of, for example, an increased numerical aperture of an objective lens and the use of short wavelength illumination for a smaller light beam spot. The efforts have been successful and the storage capacity optical disks are getting larger year after year. Technology has already established as to a DVD-ROM (Digital Versatile Discs for Read Only Memory) as an optical disk which now has doubled its capacity owning to double layer structure. A document entitled “A 16.8 GB Double-Decker Phase Change Disc” distributed in Joint International Symposium on Optical Memory and Optical Data Storage 1999 discloses an optical disk with an added density thanks to the double data storage layers which are writeable and readable. In the optical disk disclosed in the document, each data storage layer is made of phase change material. Such optical disks are classified into two types: Low-to-high media which has a higher reflectance in recording mark areas than in interval areas interposed between recording mark areas and high-to-low media which conversely has a higher reflectance in interval areas than in recording mark areas. Both types of media enable the readout of data by means of quantities of reflected and transmitted light which vary depending on whether the phase change material is in polycrystal or amorphous phase. Similar optical disks using phase change material are disclosed in, for example, Japanese Laid-open Patent Application 2001-52342 (Tokukai 2001-52342, published on Feb. 23, 2001). However, for example, on the high-to-low medium having a higher reflectance in interval areas than in recording mark areas, mark rows which include low reflectance amorphous areas are formed along guiding grooves in recorded areas. In the optical disk, data is written or read on a first data storage layer close to the light-striking side and on a second data storage layer far from the light-striking side using light incident to the same side of the disk, the light beam first travels through the first data storage layer before writing or reading data on the second data storage layer. Accordingly, upon writing or reading on the second data storage layer, the intensity of light beam reaching the second data storage layer after passing through the first data storage layer must differ depending on whether or not the first data storage layer already holds any records, so as to produce different writing or reading power sensitivities with respect to the second data storage layer. Therefore, to write or read data on the second data storage layer, the first data storage layer must be checked first to determine whether there are any records on it, so that the write or read light beam intensity can be specified. This adds complexity to the write/read system. A problems arises here that optical writing/reading system using such an optical disk is hardly practicable. As mentioned above, Japanese Laid-open Patent Application 2001-52342 discloses an optical disk having a double data storage layer structure in which address information is provided in the form of wobbling groove so as to achieve stable writing and readout. Referring to FIG. 64, an optical disk 501 provided with conventional double data storage layers has a center hole 502 at the center. Data is written/read in a recordable area 503 in which a spiral guiding groove is provided for data write and readout. The optical disk 501 has an address area 504 occupying a certain angular part. Address information is stored in the address area 504 as address pit rows extending radially. Throughout this text, this configuration, in which address information is stored collectively in one place, i.e., the address area 504 in the case of the optical disk 501, will be referred to as a lumped address scheme. FIG. 65 shows the optical disk 501 in vertical cross section. The optical disk substrate 506 has thereon a guiding-groove-formed layer 507 on whose surface a spiral guiding groove is formed from depressions and projections, a second storage layer 508, a guiding-groove-formed intermediate layer 509, a first storage layer 510, surface-coating layer 511 which are deposited in the order. To write/read data on the first storage layer 510 and the second storage layer 508 in the optical disk 501, a focused light beam 512 is shone onto the first and second storage layers 510, 508 via only one side of the disk, that is, the side of the surface-coating layer 511. FIG. 66 shows an enlarged view of a guiding groove 513 and a part of address pit rows 515 in the address area 504. On the optical disk 501, recording marks 1114 are formed along the spiral guiding groove 513, and the address pit rows 515 are formed extending from the guiding groove 513 in the address area 504. To read/write data on the first storage layer 510 in the optical disk 501, as shown in FIG. 67, the light beam 512 to focused to illuminate the first storage layer 510 by means of tracking along the guiding groove 513 on the first storage layer 510 while controlling the intensity of the light beam. To read/write data on the second storage layer 508, the light beam 512 is focused to illuminate the second storage layer 508 by means of tracking along the guiding groove 513 on the second storage layer 508 while controlling the intensity of the light beam. Under these conditions, let us suppose that the optical disk 501 is a phase change storage medium of a high-to-low type in which, for example, interval areas have high reflectance, i.e., lower transmittance, than the recording marks 1114 on the first storage layer 510 and the second storage layer 508. In the event, to read/write data on the second storage layer 508, a light beam 512d passes through the area where there is the guiding groove 513 on the first storage layer 510 and is focused onto the second storage layer 508, only after having passed through the area where there exist the recording marks 1114 which have relatively better transmittance. In contrast, a light beam 512d passes through the address area 504 of the first storage layer 510 and is focused onto the second storage layer 508, only after having passed through the area where there are no recording marks 1114 which have higher transmittance, that is, a low transmittance area. Therefore, the intensity of the light beam 512e having passed through the area where there is the guiding groove 513 on the first storage layer 510 becomes greater than that of the light beam 512d having passed through the address area of the first storage layer 510. Therefore, referring back to FIG. 66, as to the optical disk 501 having address area where address pit rows 515 are lumped together, the intensity of a light beam focused onto the second storage layer 508 varies between the address area 504 and the other area where the guiding groove 513 is provided. This makes it impossible perform stable write/readout. To solve these problems, in the aforementioned prior art patent publication, no address area 504 with address pit rows 515 in FIG. 66 is provided. Instead, it suggests that the variations in intensity of the light beam focused on the second storage layer 508 be restrained by providing a wobbling guiding groove to record address information in the form of wobbles. Throughout this text, the configuration, in which address information is not stored collectively in one place, but distributed will be referred to as a distributed address scheme. However, in the configuration disclosed in the prior art patent publication, address information is stored on the guiding groove in the form of its wobbles. Therefore, the guiding groove needs be scanned over a relatively long period of time to retrieve a single set of address information. Specifically, each address pit in the address pit rows 515 in FIG. 66 has a diameter which is more or less equal to the width of the guiding groove 513: typically, 0.3 microns to 0.5 microns, and each set of address information is recorded over about 1 mm or less of the guiding groove 513 in the address area 504. In contrast, in the case of wobbling guiding grooves, to ensure that the quantity of reflected light does not vary in tracking, each wobble must be several tens of microns long, that is, each address area storing a set of address information must be about 100 mm long in a wobbling guiding groove. In a lumped address scheme using address pit rows 515, address information is completely reproduced when about 1 mm or less of the address area is scanned. Meanwhile, in a distributed address scheme using a wobbling guiding groove, address information is completely reproduced only when about 100 mm of the guiding groove is scanned, which is relatively long. Distributed address scheme is therefore not to achieve high speed randomly access in optically reading/writing data on optical disks. Lumped address scheme should hence be employed to reproduce address information instantly. Now referring to FIG. 68, another conventional optical disk 601 has a center hole 602, a recordable area 603, innermost part 604, an outermost part 605, and prepit areas 606. The optical disk 601 is provided with a guiding groove (not shown) which is, for example, spiral. Tracking is done along the guiding groove to read/write data in the recordable areas 603 by shining a light beam 621 onto first and second storage layers (double layers) 611, 612 as shown in FIG. 69. In the prepit areas 606, or the inner prepit area 606a and outer prepit area 606b, of the first and second storage layer 611, 612, are there formed pit rows (not shown) which form, for example, a spiral. Tracking is done along the pit rows, and a light beam 621 is shone to reproduce prerecorded information from the pit rows. FIG. 70 shows an enlarged view around the border between the recordable area 603 and a prepit area 606. FIG. 71 shows its cross section in which only the first storage layer 611 and the second storage layer 612 are depicted. The following description assumes that the first and second storage layers 611, 612 are formed in a phase change storage medium of a low-to-high type whose transmittance is higher in produced recording marks than in non-recorded areas. As shown in FIG. 70 and FIG. 71, if the first storage layer 611, located on the light-striking side, has a prepit area 606, light beams 621a, 621b are focused and shone onto the second storage layer 612 after recording marks M are formed along the guiding groove G in the recordable area 603 of the first storage layer 611. In this case, intensity differs between the light beam 621a, which is transmitted through the recordable area 603 and then focused, and the light beam 621b, which is transmitted through the prepit area 606 and then focused. In the recordable area 603 do there exist multiple recording marks M with high transmittance, and the light beam 621a transmitted through the recordable area 603 of the first storage layer 611 has a relatively high intensity. In the prepit area 606 do there exist no recording marks M, and the light beam 621b transmitted through the prepit area 606 of the first storage layer 611 has a relatively low intensity. As could be understood from this, the provision of a prepit area 606 in the first storage layer 611 causes undesirable variations in reading/writing power in reading/writing and makes it impossible to read/write data on the second storage layer 612 in a stable manner. The present invention has an objective to offer an optical storage medium, an optical read/write apparatus, and an optical read/write method, with which light can be shone with uniform intensity across the substantially entire recordable area of the second data storage layer without using a complex read/write system even under such conditions that the transmittance to light of the first data storage layer in the recordable area may vary depending on whether any data is recorded in the recordable area. In order to achieve the foregoing object, an optical storage medium of the present invention includes stacked data storage layers each of which is readable/writeable separately from the other layers by means of only a light beam striking one side of the optical storage medium, and is characterized in that a recordable area of a first data storage layer has adjacent to an end thereof an extended area covering more than an area directly above a recordable area of a second data storage layer in a direction in which the first and second data storage layers are stacked, the first data storage layer being one of the data storage layers which is located closest to a light-striking surface of the medium, the second data storage layer being another of the data storage layers which is located next to the first data storage layer, opposite the light-striking surface. According to the arrangement, the recordable area of the first data storage layer has adjacent to an end thereof an extended area covering more than an area directly above a recordable area of a second data storage layer in a direction in which the first and second data storage layers are stacked. Therefore, if data is read/written from/in the recordable area of the second data storage layer after fully recording the recordable area of the first data storage layer, substantially all the read/write light striking the second data storage layer after passing through the first data storage layer passes through the recorded recordable area of the first data storage layer upon reading/writing on the second data storage layer. Therefore, light can be projected at uniform intensity on substantially all recordable areas of the second data storage layer even when the optical transmittance of the recordable area of the first data storage layer varies depending whether the recordable area is fully recorded or not. Therefore, desirable read/write characteristics can be imparted without using a complex read/write system. An optical read/write apparatus of the present invention causes a read/write light beam from illuminating means to strike only one side of an optical storage medium, and is characterized in that the apparatus includes controlling means for controlling the illuminating means so that the extended area of the optical storage medium is fully recorded before a recordable area of the first data storage layer of the optical storage medium is recorded except for the extended area. An optical read/write method of the present invention includes the step of fully recording the extended area before recording a recordable area of the first data storage layer of the optical storage medium except for the extended area. According to the arrangement, since the optical storage medium has an extended area in the recordable area of the first data storage layer, light can be projected at uniform intensity on substantially all recordable areas of the second data storage layer. Therefore, desirable read/write characteristics can be imparted without using a complex read/write system. The part of the recordable area of the first data storage layer other than the extended area is as large as the recordable area of the second data storage layer. The illuminating means is controllable in terms of its position relative to the optical storage medium in the same manner in reading/writing in the part of the recordable area of the first data storage layer other than the extended area and the recordable area of the second data storage layer. Another object of the present invention is to provide an optical storage medium, an optical read/write apparatus, and an optical read/write method, with which a desirable reading/writing property can be realized in an arrangement, using a lumped address scheme, which includes data storage layers. In order to achieve the foregoing object, an optical storage medium of the present invention includes stacked data storage layers each of which is readable/writeable separately from the other layers by means of only a light beam striking one side of the optical storage medium, and each of the data storage layers has at least one address area where there are collectively formed address information portions representing address information, and the optical storage medium exhibits an optical transmittance which varies when data is written by means of the light beam, wherein the address area of a first data storage layer includes a recorded area exhibiting a varied transmittance and a non-recorded area exhibiting an original transmittance, and the first data storage layer is one of the data storage layers which is located closest to a light-striking surface of the medium, and a second data storage layer is another of the data storage layers which is located next to the first data storage layer, opposite the light-striking surface. An optical read/write apparatus of the present invention causes a read/write light beam from illuminating means to strike only one side of an optical storage medium including stacked data storage layers each of which is readable/writeable separately from the other layers by means of only a light beam striking one side of the optical storage medium, and each of the data storage layers has at least one address area where there are collectively formed address information portions representing address information, and the optical storage medium exhibits an optical transmittance which varies when data is written by means of the light beam, and the optical read/write apparatus includes controlling means for controlling the illuminating means so that the address area of a first data storage layer includes a recorded area exhibiting a varied transmittance and a non-recorded area exhibiting an original transmittance, and the first data storage layer is one of the data storage layers which is located closest to a light-striking surface of the medium, and a second data storage layer is another of the data storage layers which is located next to the first data storage layer, opposite the light-striking surface. An optical read/write method of the present invention includes the step of causing a read/write light beam to strike only one side of an optical storage medium including stacked data storage layers each of which is readable/writeable separately from the other layers by means of only a light beam striking one side of the optical storage medium, and each of the data storage layers has at least one address area where there are collectively formed address information portions representing address information, and the optical storage medium exhibits an optical transmittance which varies when data is written by means of the light beam, wherein the address area in a first data storage layer includes a recorded area exhibiting a varied transmittance and a non-recorded area exhibiting an original transmittance, and the first data storage layer is one of the data storage layers which is located closest to a light-striking surface of the medium, and a second data storage layer is another of the data storage layers which is located next to the first data storage layer, opposite the light-striking surface. According to the arrangement, upon writing or reading on the second data storage layer, the intensity of light beam reaching the second data storage layer after passing through the address area of the first data storage layer on the light-striking side can be made to be almost the same as the intensity of a light beam reaching the second data storage layer after passing through the non-address area in the recordable area of the first data storage layer. As a result, it is possible to read/write data from/in the second data storage layer steadily and desirably. That is, as to the optical storage medium, the non-address area in the recordable area of the first data storage layer has a recorded area, for example, a recording mark is formed, so that the optical transmittance varies at the portion. In a case where the address area does not have the recorded area exhibiting a varied transmittance, upon reading or writing on the second data storage layer, there is a great difference between the intensity of the light beam reaching the second data storage layer after passing the non-address area and the intensity of the light beam reaching the second data storage layer after passing the address area. On the other hand, the present invention is arranged so that the address area in the first data storage layer of the optical storage medium includes a recorded area exhibiting a varied transmittance and a non-recorded area exhibiting an original transmittance. Thus, also in the address area, an optical transmittance is varied due to the recorded area as in the non-address area. Therefore, as described above, the intensity of the light beam reaching the second data storage layer after passing through the address area of the first data storage layer on the light-striking side can be made to be almost the same as the intensity of light beam reaching the second data storage layer after passing through the non-address area in the recordable area of the first data storage layer. As a result, it is possible to read/write data from/in the second data storage layer steadily and desirably. According to the optical read/write apparatus or the optical read/write method, in a case where the recorded area is formed on the address area in the first data storage layer of the optical storage medium, it is possible to manufacture the optical storage medium at a lower cost since the manufacturing process of the optical storage medium is simplified. Further, still another object of the present invention is to provide an optical storage medium, an optical read/write apparatus, and an optical read/write method, with which data can be read/written steadily without being influenced by a prepit area. This is realized in an optical disc having two or more storage layers. In order to achieve the foregoing object, an optical storage medium of the present invention includes: one light-striking-side storage layer provided as a data storage layer on a light-striking side; and one or more opposite-side storage layers provided as data storage layers opposite the light-striking side from the light-striking-side storage layer, wherein, in order to solve the foregoing problems, one of the opposite-side storage layers which is, as a last data storage layer, most distanced from the light-striking-side storage layer has a prepit area which includes preformed pits representative of data. According to the arrangement, since the last data storage layer, most distanced from the light-striking-side storage layer, has a prepit area, intensity of the striking light is not varied by the prepit area. Thus, it is possible to read/write data from/in the last data storage layer steadily without being influenced by the prepit area. An optical read/write apparatus of the present invention causes a read/write light beam from an illuminating section to strike only one side of the optical storage medium, wherein the optical read/write apparatus includes: the optical read/write apparatus includes: an envelope detecting section for detecting an envelope of a reproduction signal obtained from the prepit area; a mean level producing section for producing a mean level of the detected envelope; and a digital converting section for converting the reproduction signal to a digital signal using the mean level as a reference. An optical read/write method of the present invention causes a read/write light beam from an illuminating section to strike only one side of the optical storage medium, wherein the method further includes the steps of: producing a mean level of an envelope of a reproduction signal obtained from the prepit area; and converting the reproduction signal to a digital signal using the mean level as a reference. According to the foregoing apparatus and method, an envelope of a reproduction signal obtained when the prepit area is reproduced is detected by the envelope detecting section. Then, the mean level producing section produces a mean level of the detected envelope. Thereafter, the digital converting section converts the reproduction signal to a digital signal using the mean level as a reference. Thus, the mean level is always detected, and the detected mean level is used as a reference in the digital conversion, so that it is possible to perform the digital conversion without being influenced by variance in amplitude of the reproduction signal. For example, in a case where there exist a fully recorded portion exhibiting high transmittance after recording and an unrecorded portion which holds no record, when a light beam that is projected so as to cover the fully recorded portion and the unrecorded portion is focused on the second storage layer, it is possible to steadily obtain a digital signal from the reproduction signal even though the reproduction signal strength of prepit data varies in connection with rotation of the optical storage medium. Thus, it is possible to-steadily reproduce the prepit data on the second storage layer of the optical storage medium. For a fuller understanding of the nature and advantages of the invention, reference should be made to the ensuing detailed description taken in conjunction with the accompanying drawings. [Embodiment 1] The following will describe an embodiment of the present invention in reference to FIGS. 1–8. Referring to FIG. 2, an optical disk (optical storage medium) 1 of the present embodiment has a center hole 2 at its center and a recordable area 3 relatively close to the circumference in relation to the center hole 2. On the recordable area 3, a spiral read/write guiding groove is formed enabling data readout and write. Broken lines in the figure indicate an innermost part (portion) 4 and an outermost part (portion) 5 of the recordable area 3. Referring to FIG. 3 showing a vertical cross-sectional view of the optical disk 1, the disk 1 has on a disk substrate 6 a guiding-groove-formed layer 7, a second storage layer (second data storage layer) 8, a guiding-groove-formed intermediate layer 9, a first storage layer (first data storage layer) 10, and a surface-coating layer 11, all the layers being stacked in this order. To read/write data in the first storage layer 10 or the second storage layer 8 of the optical disk 1, a light beam 12 is always projected on the same side of the disk 1, i.e., the side where the surface-coating layer 11 is provided, so that the light beam is concentrated on the targeted, first or second storage layer 10, 8. The structure of the optical disk 1 is shown in FIG. 4 in more detail. In the figure, the disk substrate 6 is made of, for example, a transparent polycarbonate substrate which is 1.2 mm thick. The guiding-groove-formed layer 7 is made of, for example, an ultraviolet-ray-setting resin layer which is 20 microns thick. On the surface of the layer 7 which interfaces the second storage layer 8, a spiral guiding groove 13 is formed from depressions and projections. The guiding-groove-formed layer 7 is formed, for example, by a pattern transfer technology termed 2P method. The second storage layer 8 is made up of, for example, an AlTi-alloy reflective film 14, a ZnS—SiO2 interference film 15, a SiN protective film 16, a GeSbTe phase change recording layer 17, a SiN protective film 18, and a ZnS—SiO2 interference film 19. These layers are sequentially stacked on the guiding-groove-formed layer 7 by sputtering. As with the guiding-groove-formed layer 7, the guiding-groove-formed intermediate layer 9 is made of, for example, an ultraviolet-ray-setting resin layer which is 20 microns thick. On the surface of the intermediate layer 9 which interfaces the first storage layer 10, the guiding groove 13 is formed. The guiding-groove-formed layer 9 is again similarly formed, for example, by a pattern transfer technology termed 2P method. As with the second storage layer 8, the first storage layer 10 is made up of, for example, a ZnS—SiO2 interference film 20, a SiN protective film 21, a GeSbTe phase change recording layer 22, a SiN protective film 23, and a ZnS—SiO2 interference film 24. These layers are sequentially stacked on the guiding-groove-formed intermediate layer 9 by sputtering. The surface-coating layer 11 is made of, for example, an ultraviolet-ray-setting resin layer which is 80 microns thick. To form the layer 11, an ultraviolet-ray-setting resin is applied on the first storage layer 10 by spin coating and then cured by ultraviolet ray illumination. The optical disk substrate 6 is, as mentioned in the foregoing, a transparent polycarbonate substrate. However, if the light beam 12 is incident only to the side of the surface-coating layer 11 as is the case with the optical disk 1 of the present embodiment, the disk substrate 6 is not necessarily transparent and may be an opaque metallic substrate. The optical disk 1 of the present embodiment has the guiding-groove-formed layer 7 with the guiding groove 13, and the guiding-groove-formed layer 7 is formed by 2P method. Alternatively, for example, the optical disk 1 may be formed by preparing the disk substrate 6 by injection molding and directly forming the guiding groove 13 on the optical disk substrate 6, in which case the guiding-groove-formed layer 7 is unnecessary. The surface-coating layer 11 is formed on the first storage layer 10 by spin coating. Alternatively, the layer 11 may be a transparent sheet of uniform thickness pasted onto the first storage layer 10. The optical disk 1 has the guiding-groove-formed layer 7, the second storage layer 8, the guiding-groove-formed intermediate layer 9, the first storage layer 10, and the surface-coating layer 11 sequentially stacked on the optical disk substrate 6. Alternatively, the layers may be stacked on the optical disk substrate 6 in the order to the guiding-groove-formed layer 7, the first storage layer 10, the guiding-groove-formed intermediate layer 9, the second storage layer 8, and the surface-coating layer 11, with the light beam 12 being projected onto the side on which the optical disk substrate 6 is located, in which case the films which will eventually constitute the first storage layer 10 and the second storage layer 8 must be formed in the reverse order from the case illustrated in FIG. 4. An optical-disk-read/write apparatus (optical read/write apparatus) to read/write data on the optical disk 1 has the structure shown in FIG. 5. In the optical-disk-read/write apparatus 31, the optical disk 1 is fixed to the spindle 33 of the motor at the center hub and rotated. The optical-disk-read/write apparatus 31 includes an optical system unit 34 and a signal processing and controlling unit (controlling means) 35. The optical system unit 34 includes an illumination source 41, such as a semiconductor laser, a collimator lens 42, a beam splitter 43, an objective lens 44, a double-axis actuator 45, a collective lens 46 and a light-receiving element 47. The objective lens 44 is supported by the double-axis actuator 45 and moved along a focusing direction and a tracking direction. The light-receiving element 47 includes a reproduction signal detecting element, a focus error signal detecting element, and a tracking error signal detecting element. The outputs of the detecting elements are fed to the signal processing and controlling unit 35. The optical system unit 34 is driven by a slide driving unit (not shown) so as to reciprocally move along the radius of the optical disk 1. The signal processing and controlling unit 35 implements various signal processing and controlling operations. For example, the illumination source 41 is controlled in terms of output power in read/write operations. The double-axis actuator 45 is controlled in response to the outputs of the focus error signal detecting element and the tracking error signal detecting element, to control the focusing and tracking actions of the objective lens 44. The signal processing and controlling unit 35 further controls the slide driving unit and hence the movement of the optical system unit 34 along the radius of the optical disk 1. Thereby, the optical system unit 34, hence the objective lens 44, is moves to a position where the unit 34 can read/write data on a predetermined track. Other control actions of the signal processing and controlling unit 35 will be described later. In the optical-disk-read/write apparatus 31, the light beam 12 is concentrated on either the first storage layer 10 or the second storage layer 8 by the mechanism discussed in the foregoing, so that data is read/written from/into either the first storage layer 10 or the second storage layer 8 along the guiding groove 13. In the present embodiment, in the optical-disk-read/write apparatus 31, data is read/written from/into the second storage layer 8 only after the recordable area 3 of the first storage layer 10 is fully recorded. Actions in this case are implemented by the signal processing and controlling unit 35 which controls the optical system unit (illuminating means) 34 and the slide driving unit (illuminating means). Actions in this case are shown in FIG. 1. Referring to that figure, when the read/write light beam 12 is projected to the second storage layer 8, the recordable areas 3 of the first storage layer 10 are fully recorded in advance (shown in black). Therefore, the light beam 12 is transmitted through the fully recorded, first storage layer 10 and projected to the second storage layer 8. Assuming the foregoing structure, the following will describe how the optical-disk-read/write apparatus 31 reads/writes data on the optical disk 1. In the optical-disk-read/write apparatus 31, the light beam 12 emitted by the illumination source 41 is collimated by the collimator lens 42, transmitted through the beam splitter 43, before entering the objective lens 44. Then, the light beam 12 is focused by the objective lens 44 on either the first storage layer 10 or the second storage layer 8 of the optical disk 1. The reflection from the optical disk 1 passes through the objective lens 44, deflected by the beam splitter 43, and focused by the collective lens 46 on the light-receiving element 47. Thereafter, based on the output of the light-receiving element 47, the signal processing and controlling unit 35 controls the double-axis actuator 45 and hence the objective lens 44 for its precise focusing and tracking actions. Thus, in the optical-disk-read/write apparatus 31, to read/write data from/into either the first storage layer 10 or the second storage layer 8, the light beam 12 is focused on that storage layer along the guiding groove 13. In the foregoing situation, the following will describe how the optical-disk-read/write apparatus 31 reads/writes data on the optical disk 1, provided that data is recorded starting with the innermost part 4 of the recordable area 3 of the first storage layer 10 of the optical disk 1 until data fills part of the recordable area 3 of the first storage layer 10 and then the operation moves to reading/writing data in the second storage layer 8. It is also supposed that the optical disk 1 is a high-to-low medium such that the interval area is more reflective than the recording mark area and data is recorded by phase change. As a result of recording in the first storage layer 10, as shown in FIGS. 6, 7, a recorded area 51 (shown by hatched lines) shown is produced covering the innermost part 4 of the recordable area 3 of the first storage layer 10 up to partway of the recordable area 3. Here, the first storage layer 10 is more optically transmissive in the recorded area 51 than other areas. As a result, the light beam 12 projected on the second storage layer 8 is more intense when it is concentrated on the second storage layer 8 if it has passed through the recorded area 51 than if it has passed through an area other than the recorded area 51 (a non-recorded area). In other words, in recording data into the second storage layer 8, the light beam 12 varies in intensity when it reaches the second storage layer 8 after passing through the first storage layer 10, depending on whether it has come through the recorded area 51. In this case, to record data into the second storage layer 8, a complex write system is required which can vary the light beam 12 in intensity depending on whether there are any records stored in the first storage layer 10. The same description applies to the case where data is read from the second storage layer 8, and a similarly complex read system is required, because the return light reflected off the second storage layer 8 changes in quantity depending on whether the light beam 12 has passed through the recorded area 51 of the first storage layer 10. Accordingly, in the optical-disk-read/write apparatus 31 of the present embodiment, as shown in FIG. 1, data is read/written from/into the second storage layer 8 only after the recordable area 3 of the first storage layer 10 is fully recorded. In other words, to record data on the optical disk 1, the optical-disk-read/write apparatus 31 first writes data in the first storage layer 10, and only after the recordable area 3 of the first storage layer 10 is recorded to its full capacity, starts writing or reading data into/from the second storage layer 8. The operation ensures that in the read/write operation as to the second storage layer 8, the light beam 12 projected on the second storage layer 8 always passes through the fully recorded, first storage layer 10 before entering the second storage layer 8. In both read and write operations, the light beam 12 has a constant intensity when it reaches the second storage layer 8, which eliminates the need to use a complex read/write system to control the intensity of the light beam 12. Stable read/write operations are thus achieved. To carry out such operations, the signal processing and controlling unit 35 is provided with a write-start address producing circuit 81 and an illuminating-unit-controlling circuit 82 as shown in FIG. 8. The illuminating unit controlled by the illuminating-unit-controlling circuit 82 is inclusive of, for example, the optical system unit 34 and the slide driving unit. To write data on the optical disk 1, first, a recording status managing signal is reproduced from data recorded in a recording status managing area of the optical disk 1, and the signal is all recorded in the write-start address producing circuit 81 in the signal processing and controlling unit 35. The recording status managing area is provided at a particular position in the first storage layer 10. The recording status managing area may contain the title of the recorded material, as well as an address representing a recording range. Thereafter, the write-start address producing circuit 81 produces a write-start address for the optical disk 1, and the illuminating-unit-controlling circuit 82 controls focus and tracking so as to move the light beam spot to the write-start address. This action triggers recording in the recordable area 3 of the first storage layer 10. Thereafter, data is written to the first storage layer 10 to its full capacity, that is, until the last address of the first storage layer 10 is detected. If data is written to the second storage layer 8 without a break, the light beam 12 is concentrated on the second storage layer 8 to similarly carry out recording in the recordable area 3 of the second storage layer 8. [Embodiment 2] The following will describe another embodiment of the present invention in reference to FIGS. 9–11. An optical disk 61 of the present embodiment is operational with the optical-disk-read/write apparatus 31 which works as described in the foregoing. The optical disk 61 of the present embodiment has extended areas 62 in the innermost part (portion) 4a and the outermost part (portion) 5a of the recordable area 3a of the first storage layer 10 as shown in FIGS. 9, 10. Therefore, the innermost part (portion) 4a of the first storage layer 10 extends further inwards in relation to the diameter of the optical disk 1 when compared to the innermost part 4b of the second storage layer 8. The outermost part (portion) 5a of the first storage layer 10 extends further outwards in relation to the diameter when compared to the outermost part 5b of the second storage layer 8. In other words, the recordable area 3a of the first storage layer 10 is greater than the area of the recordable area 3b of the second storage layer 8 by the extended areas 62 in the innermost part (portion) 4a and in the outermost part (portion) 5a. FIG. 9 is used to show the innermost parts 4a, 4b and the outermost parts 5a, 5b for convenience. No matter how large or small the extended areas 62 are, their mere provision reduces the loss in intensity of a light beam projected to the recordable area 3b of the second storage layer 8 as will be described later. To further and preferably reduce the loss in intensity of such a light beam, each extended area 62 should be specified enough wide (or long when measured along a diameter of the optical disk 1) that the light beam 12 may not spill out of the recordable area 3a, inclusive of the extended area 62, of the first storage layer 10 regardless whether the light beam 12 is focused on the innermost part 4b or the outermost part 5b of the recordable area 3b of the second storage layer 8. FIG. 11 shows an optical disk for comparison to explain the functions of the optical disk 61. In the optical disk 63, the recordable area of the first storage layer 10 is as large as that of the second storage layer 8. The innermost part 4 and the outermost part 5 in the first storage layer 10 are positioned directly above and occupy the same area as their equivalents of the second storage layer 8. As shown in FIGS. 9, 11, in both optical disks 61, 63, the first storage layer 10 and the second storage layer 8 each have a guiding groove 13, and the first storage layer 10 is fully recorded along the guiding groove 13 up to either the innermost part 4a, 4 or the outermost part 5a, 5 of the recordable area 3a, 3. In the figures, the fully recorded status of the guiding groove 13 is shown by bold lines. In other words, in the readout/write on the optical disks 61, 63, the optical-disk-read/write apparatus 31, again, first writes data in the recordable area 3a, 3 of the first storage layer 10 to its full capacity before data is read/written in the recordable area 3b, 3 of the second storage layer 8. In the arrangement, as to the optical disk 63 equipped with recordable areas 3 with no extended area 62 on the first storage layer 10, the light beam 12b projected on the recordable area 3 of the second storage layer 8 somewhere midway in relation to the radius of the disk to read/write data in the second storage layer 8 passes entirely through the recordable area (fully recorded area) 3 where the first storage layer 10 exhibits a relatively high transmittance. By contrast, the light beam 12c, if projected close to the innermost part 4 or the outermost part 5 of the second storage layer 8, does not entirely passes through the recordable area (fully recorded area) 3 where the first storage layer 10 exhibits a relatively high transmittance, but partially passes through unrecordable areas 64 other than the recordable area 3 where the first storage layer 10 exhibits a relatively lower transmittance. Accordingly, the light beam 12c is less intense than the light beam 12b. Therefore, in reading/writing data in the second storage layer 8, the light beam decreases, i.e., varies, in intensity in the innermost part 4, the outermost part 5, and their neighborhoods of the recordable area 3 of the second storage layer 8, making it difficult to perform stable read/write operations across the entire recordable area 3 of the second storage layer 8. By contrast, the optical disk 61 of the present embodiment is provided with recordable areas 3a with extended areas 62 on the first storage layer 10. Thus, the light beam projected on the recordable area 3b of the second storage layer 8 to read/write data in the second storage layer 8 illuminates passes through the recordable area (fully recorded area) 3a where the first storage layer 10 exhibits a relatively high transmittance not only when the light is directed on the second storage layer 8 somewhere midway in relation to the radius of the disk, but also when the light is directed on the innermost part 4b or the outermost part 5b of the second storage layer 8. Thus, with the optical disk 61 of the present embodiment, the light beam projected on the recordable area 3b of the second storage layer 8 always becomes the light beam 12b which has passed through the recordable area (fully recorded) 3a where the first storage layer 10 exhibits a relatively high transmittance. The light beam does not vary in intensity whether data is read/written from/into any part of the recordable area 3b of the second storage layer 8. Stable read/write operations are thus achieved. To perform read/write operation on the second storage layer 8, the light beam 12 projected on the first storage layer 10 has a radius not exceeding the thickness of the guiding-groove-formed intermediate layer 9. Therefore, the extended area 62 is sufficiently wide (or long when measured along a diameter of the optical disk) if it is as wide (or long) as the guiding-groove-formed intermediate layer 9 is thick. If the guiding groove 13 on the first storage layer 10 is not concentric to the guiding groove 13 on the second storage layer 8, the extended area 62 should be designed as wide as the guiding-groove-formed intermediate layer 9 is thick, plus the deviation. FIG. 9 is a schematic view, and the extended area 62 is shown as wide as the area covering two guiding grooves 13. However, in practice, the extended area 62 is as wide as the area covering at least 60 guiding grooves 13, because the guiding grooves 13 have a pitch of about 0.3 microns and the guiding-groove-formed intermediate layer 9 has a thickness of about 20 microns. In addition, the extended area 62 may be formed in only one of the innermost part 4a and the outermost part 5a of the first storage layer 10, in which case the extended area 62 is functional as described in the foregoing where it is formed. [Embodiment 3] The following will describe a further embodiment of the present invention in reference to FIGS. 12–20. An optical disk 71 of the present embodiment is operational with the optical-disk-read/write apparatus 31 which works as described in the foregoing. The optical disk 61 has an extended area 62 in the innermost part 4a and the outermost part 5a of the recordable area 3a of the first storage layer 10. The optical disk 71 of the present embodiment has a fully prerecorded pseudo-recording area 72 in an area which is an equivalent of the extended area 62 as shown in FIGS. 12, 13. Therefore, on the optical disk 71 of the present embodiment, the recordable area 3 where ordinary information is recorded is as great on the first storage layer 10 as it is on the second storage layer 8. The pseudo-recording area 72 may be provided before the optical disk 71 is shipped out, for example. In the arrangement, to perform normal read/write on the optical disk 71, similarly to the foregoing case, the optical-disk-read/write apparatus 31 first writes data in the first storage layer 10, and only after the recordable area 3 is recorded to its full capacity, starts writing or reading in recordable area 3 of the second storage layer 8, in which case, the pseudo-recording area 72 is already fully recorded. As mentioned in the foregoing, the optical disk 71 of the present embodiment has a pseudo-recording area 72 inside the innermost part 4b and outside the outermost part 5b of the recordable area 3 of the first storage layer 10 in relation to the diameter of the disk 71. Therefore, to perform read/write in the second storage layer 8, similarly to the case of the optical disk 61, the light beam projected on the recordable area 3 of the second storage layer 8 always becomes the light beam 12b having passed through a fully recorded area where the first storage layer 10 has a relatively high transmittance. The light beam does not vary in intensity whether data is read/written from/into any part of the recordable area 3 of the second storage layer 8. Stable read/write operations are thus achieved. Further, unlike the optical disk 61, the optical disk 71 has the recordable area 3 which is as large on the first storage layer 10 as on the second storage layer 8, and the guiding grooves 13 on the recordable area 3 may share a common format. As a result, the optical system unit 34 is controlled in terms of its position in performing read/write on the first storage layer 10 in the same manner as in performing read/write on the second storage layer 8. The pseudo-recording area 72 may be formed on the optical disk 61 with an extended area 62, by the optical-disk-read/write apparatus 31 recording data in that extended area 62 to the full capacity. The optical disk 71 can be thus made from an optical disk 61. In such an arrangement, it is not necessary to fabricate an optical disk 71 by forming a pseudo-recording area 72 on an optical disk 61 prior to shipment. The omission of the step allows for reduction of the cost of the optical disk 61 (71). The optical-disk-read/write apparatus 31 forms a pseudo-recording area 72 by fully recording the extended area 62 prior to ordinary recording in the first storage layer 10, for example, when the optical disk 61 is loaded into the optical-disk-read/write apparatus 31. In this case, the optical-disk-read/write apparatus 31 first reads data from an extended area 62 of the loaded optical disk 61, and if the extended area 62 is not fully recorded, records data in the area 62 to its full capacity. The process is controlled by the signal processing and controlling unit 35 of the optical-disk-read/write apparatus 31. To implement such control, the signal processing and controlling unit 35 is provided with an extended-area-recording-status-checking circuit 83 and an illuminating-unit-controlling circuit 82 (detailed in the foregoing) as shown in FIG. 14. In the arrangement, as the optical disk 61 is loaded, the optical-disk-read/write apparatus 31 first reads data from its extended area. The extended-area-recording-status-checking circuit 83 checks based on a reproduction signal from the extended area 62 whether or not the extended area 62 is fully recorded. If the check turns out that the extended area 62 is not fully recorded, the extended-area-recording-status-checking circuit 83 regards the loaded optical disk 61 as being never used, and supplies an extended-area-writing-instruction signal to the illuminating-unit-controlling circuit 82 prior to the start of a recording action carried out on the first storage layer 10. Upon receiving that signal, the illuminating-unit-controlling circuit 82 controls the illuminating unit so as to make the extended area 62 on the optical disk 61 fully recorded. Meanwhile, if the check turns out that the extended area 62 is fully recorded, the extended-area-recording-status-checking circuit 83 regards the loaded optical disk 61 as being already used, and supplies a normal writing-instruction signal to the illuminating-unit-controlling circuit 82. Upon receiving that signal, the illuminating-unit-controlling circuit 82 controls the illuminating unit so as to perform an ordinary recording action on the optical disk 61. The pseudo-recording area 72 may store absolutely nonsense or meaningless information. Alternatively, if the optical disk 61 is provided with the pseudo-recording area 72 before being shipped out, the pseudo-recording area 72 may contain a disk ID (identification information) or encryption code information (encryption information) which match that particular optical disk 61, but not the other disks. If the pseudo-recording area 72 contains encryption code information, the optical-disk-read/write apparatus 31 may record information in the recordable area 3 of the optical disk 71 only after the apparatus 31 encrypts the information based on the encryption code information. In this case, to record information on the optical disk 71, the optical-disk-read/write apparatus 31 first reads the encryption code information of pseudo-recording area 72 and encrypts information to be recorded, based on the encryption code information. In addition, to reproduce information from an encrypted optical disk 71, the optical-disk-read/write apparatus 31 decrypts information after readout from the recordable area 3. These processes are controlled by the signal processing and controlling unit 35. In this case, the optical-disk-read/write apparatus 31 cannot decrypt information which is read out from the optical disk 71 unless the apparatus 31 is equipped with a function to decrypt the encrypted information, which makes it possible to prevent the illegal copying and other uses of the optical disk 71. As mentioned in the foregoing, to record information on the optical disk 71 after encrypting it based on the encryption code information in the pseudo-recording area 72, the signal processing and controlling unit 35 is provided with the encrypting circuit 84 and the illuminating-unit-controlling circuit 82 as shown in FIG. 15. In the arrangement, prior to taking a recording action on the optical disk 71, the encryption code information is reproduced which is recorded in advance in the pseudo-recording area 72 of the optical disk 71. The encrypting circuit 84 encrypts recording information based on the encryption code information and supplies the encrypted recording information to the illuminating-unit-controlling circuit 82. The illuminating-unit-controlling circuit 82 controls the illuminating unit so that the recording information is recorded on the optical disk 71. In addition, if the pseudo-recording area 72 contains disk identification information, it is possible to prevent the illegal copying and other uses of the optical disk 71 by managing the disk identification information in the optical-disk-read/write apparatus 31 or in a server or the like connected to the optical-disk-read/write apparatus 31. The managing of the disk identification information refers to the processing to count the times the optical disk 71 is used to limit the times the disk is used, for example. In addition, provided that the pseudo-recording area already contains disk identification information or encryption code information, designing the pseudo-recording area 72 as a read-only area prohibits rewriting these sets of information. This further appropriately prevents the illegal copying and other uses of the optical disk 71. In addition, as mentioned earlier, when the optical-disk-read/write apparatus 31 forms the pseudo-recording area 72 on the optical disk 61 to form the optical disk 71 from the optical disk 61, the optical-disk-read/write apparatus 31 may record, in the pseudo-recording area 72, the apparatus ID information which is unique to the optical-disk-read/write apparatus 31 or encryption code information which is unique to the optical-disk-read/write apparatus 31. When the optical-disk-read/write apparatus 31 records the apparatus ID information on the pseudo-recording area 72, the signal processing and controlling unit 35 in the optical-disk-read/write apparatus 31 is equipped with an identification-information-presence-checking circuit 85 and the illuminating-unit-controlling circuit 82 as shown in FIG. 16. In the arrangement, as the optical disk 61 is loaded, the optical-disk-read/write apparatus 31 first reads the extended area. The identification-information-presence-checking circuit 85 checks based on a reproduction signal from the extended area 62 whether the apparatus ID information is present in the extended area 62. If the check turns out that the extended area 62 contains no apparatus ID information, the identification-information-presence-checking circuit 85 regards the loaded optical disk 61 as being as being never used, and supplies an identification-information-writing-instructing signal to the illuminating-unit-controlling circuit 82 prior to the start of a recording action on the first storage layer 10. Upon receiving that signal, the illuminating-unit-controlling circuit 82 controls the illuminating unit so as to record the apparatus ID information in the extended area 62 of the optical disk 61. The apparatus ID information is contained in the signal processing and controlling unit (identification information storing means) 35. Meanwhile, if the check turns out that the extended area 62 holds apparatus ID information, the identification-information-presence-checking circuit 85 regards the loaded optical disk 61 as being already used, and supplies a normal read/write-instructing signal to the illuminating-unit-controlling circuit 82. Upon receiving that signal, the illuminating-unit-controlling circuit 82 controls the illuminating unit so as to perform an ordinary read/write action on the optical disk 61. In addition, to record encryption code information in the pseudo-recording area 72 using the optical-disk-read/write apparatus 31, the signal processing and controlling unit 35 in the optical-disk-read/write apparatus 31 is equipped with an encryption-information-presence-checking circuit 86 and the illuminating-unit-controlling circuit 82 as shown in FIG. 17. In the arrangement, as the optical disk 61 is loaded, the optical-disk-read/write apparatus 31 first reads the extended area 62. The encryption-information-presence-checking circuit 86 checks based on a reproduction signal from the extended area 62 whether the encryption code information (encryption information) is present in the extended area 62. If the check turns out that the extended area 62 contains no encryption code information, the encryption-information-presence-checking circuit 86 regards the loaded optical disk 61 as being never used, and supplies an encryption-information-reading signal to the illuminating-unit-controlling circuit 82 prior to the start of a recording action on the first storage layer 10. Upon receiving the signal, the illuminating-unit-controlling circuit 82 controls the illuminating unit to record encryption code information in the extended area 62 of the optical disk 61. The encryption code information is contained in the signal processing and controlling unit (encryption information storing means) 35. Meanwhile, if the check turns out that the extended area 62 holds encryption code information, the encryption-information-presence-checking circuit 86 regards the loaded optical disk 61 as being already used, and supplies an ordinary read/write-instructing signal to the illuminating-unit-controlling circuit 82. Upon receiving the signal, the illuminating-unit-controlling circuit 82 controls the illuminating unit so as to perform an ordinary read/write action on the optical disk 61. In addition, as mentioned earlier, when the optical-disk-read/write apparatus 31 records apparatus ID information or encryption code information in the pseudo-recording area 72 (extended area 62), an arrangement may be made so that only the optical-disk-read/write apparatus 31 which did that recording can reproduce information from the recordable area 3 of the optical disk 71 (61). Processing in this case is done as below, for example. Supposing that the pseudo-recording area 72 of the optical disk 71 holds apparatus ID information, to read the optical disk 71, the optical-disk-read/write apparatus 31 first reproduce the apparatus ID information from the pseudo-recording area 72 of the optical disk 71, and then reads data from the optical disk 71 only when the apparatus ID information readout matches the apparatus ID information of the optical-disk-read/write apparatus 31 as a result of checking. To realize these actions, the signal processing and controlling unit 35 is equipped with an identification-information-match-checking circuit 87 and the illuminating-unit-controlling circuit 82 as shown in FIG. 18. In the arrangement, as the optical disk 71 is loaded, the optical-disk-read/write apparatus 31 first reads the pseudo-recording area 72. The identification-information-match-checking circuit 87 compares the apparatus ID information obtained from the reproduction signal read out from the pseudo-recording area 72 with the apparatus ID information assigned to the optical-disk-read/write apparatus 31 to check whether the two sets of apparatus ID information match. If the check turns out that the two sets of apparatus ID information match each other, a read/write-instructing signal is supplied to the illuminating-unit-controlling circuit 82. Upon receiving the signal, the illuminating-unit-controlling circuit 82 controls the illuminating unit so as to perform a read/write action on the optical disk 71. Meanwhile, if the two sets of apparatus ID information does not match each other, the identification-information-match-checking circuit 87 supplies an identification-information-match-display signal representing the situation to the illuminating-unit-controlling circuit 82. Upon receiving that signal, the illuminating-unit-controlling circuit 82 causes a display unit (not shown) to display a notice to that situation, for example. In this case, no data is read nor written on the optical disk 71. In addition, if the recordable area 3 of the optical disk 71 holds information which is encrypted based on encryption code information, to read the optical disk 71, the optical-disk-read/write apparatus 31 decrypts the information read out from the recordable area 3 based on the encryption code information of the optical-disk-read/write apparatus 31. The decryption is done, as shown in FIG. 19, in a decrypting circuit 88 in the signal processing and controlling unit 35. In these circumstances, the information read out from the recordable area 3 can be decrypted only when the encryption code information used with the optical disk 71 matches the encryption code information provided to the optical-disk-read/write apparatus 31. The arrangement enables prevention of copying, legal or illegal, of the optical disk 71. In addition, the extended area 62 of the optical disk 61 can be used as a test write area as follows. For example, the most suitable light beam intensity to write data on the optical disk 61, that is the most suitable writing power, varies depending on changes in various factors including ambient temperature. Therefore, the optical-disk-read/write apparatus 31 usually test writes data on the optical disk to calculate the most suitable writing power. Accordingly, on the optical disk 61, the extended area 62 is at least partly used as a test write area. The arrangement eliminates the need to separately provide a test write area on the optical disk 61 and enables efficient use of the recordable area 3 of the optical disk 61. To implement these actions, the signal processing and controlling unit 35 is provided with a test-write-controlling circuit 89, a writing-power-checking circuit 90, and the illuminating-unit-controlling circuit 82 as shown in FIG. 20. In the arrangement, to write data on the optical disk 61, a test-write-recording instruction is given to the test-write-controlling circuit 89 prior to writing in the first storage layer 10. Thus, the extended area 62 of the optical disk 61 is test written (recorded as test write). The test write is done with the writing power varied by little amounts. Next, the data recorded in the test write is reproduced, and the reproduction signal is supplied to the writing-power-checking circuit 90. The writing-power-checking circuit 90 determines the most suitable writing power to record data on the optical disk 61 based on the reproduction signal. Thereafter, the information representative of the most suitable writing power is supplied to the illuminating-unit-controlling circuit 82 which controls the illuminating unit so that data is written on the optical disk 61 using the most suitable writing power. The arrangement always enables recording under the most suitable conditions regardless of changes in various factors including ambient temperature and resultant changes in the recording sensitivity of the optical disk 61. Throughout the embodiments above, it was supposed that the optical disks are all high-to-low phase change types of storage media whose interval areas have higher reflectance, i.e., lower transmittance, than the recording mark areas. The foregoing arrangements are however applicable to those optical disks that may be low-to-high phase change types of storage media whose interval areas have lower reflectance, i.e., higher transmittance, than the recording mark areas. [Embodiment 4] The following will describe another embodiment of the present invention in reference to FIGS. 21–25. As shown in FIG. 23, an optical disk (optical storage medium) 101 of the present embodiment has a center hole 102 at its center and a recordable area 103 outside the center hole 102 in relation to a diameter. The innermost part and the outermost part of the recordable area 103 are shown by broken lines. The optical disk 101 employs a lumped address scheme: an address area 104 is provided occupying a predetermined angular part of the recordable area 103, and address information is represented by radially arranged address pit rows in the address area 104. In a non-address area 105, which is the part of the recordable area 103 other than the address area 104, there is provided a spiraling read/write guiding groove along which information can be read/written. Like the optical disk 1, the optical disk 101 is arranged as shown in FIG. 3 and FIG. 4. FIG. 21 shows an enlarged view of a part of the optical disk 101, where an address area 104 and non-address areas 105 adjacent to the address area 104 are depicted. Each non-address area 105 stores recording marks 111 formed by projection of a light beam 12 along the spiraling guiding groove 13. The recording mark 111 differs from surrounding portions in optical transmittance. In the address area 104, address tracks 113 made of address pits 112 are provided to extend from the guiding grooves 13 in the non-address areas 105. The address area 104 includes recorded areas where transmittance has changed and non-recorded areas where transmittance has not changed. Concretely, the (continuous) address area 104 where transmittance has changed is formed by continuously recording alternate address tracks 113 in relation to a diameter of the optical disk 101 by continuously projecting a light beam 12. In other words, one of two address tracks 113 in the address area 104 which are adjacent in the relation to a diameter of the optical disk 101 is continuously recorded, whereas the other is unrecorded. The optical-disk-read/write apparatus (optical read/write apparatus) for reading/writing the optical disk 101 was already described in reference to FIG. 5, as with the optical disk 1. For the optical-disk-read/write apparatus 31 to read/write data on the optical disk 101, the first storage layer 10 is read/written as shown in FIG. 22 by focusing and projecting the light beam 12 onto the first storage layer 10 while tracking the guiding groove 13 on the first storage layer 10 and controlling the light beam intensity. In addition, the second storage layer 8 is read/written by focusing and projecting the light beam 12 onto the second storage layer 8 while tracking the guiding groove 13 on the second storage layer 8 and controls the light beam intensity. In this situation, it is supposed that the optical disk 101 is, for example, a high-to-low phase change type of storage medium in which in the first storage layer 10 and the second storage layer 8, interval areas between the recording marks 111 have a higher reflectance, i.e., lower transmittance, than the recording marks 111. In this case, in the non-address area 105 on the first storage layer 10, the recording marks 111 have a higher transmittance. Therefore, referring to FIG. 22, the light beam 12e projected onto the second storage layer 8 after passing trough a portion of the first storage layer 10 where the recording marks 111 are present has a greater intensity than the light beam projected onto the second storage layer 8 without passing through that portion where the recording marks 111 are present. Likewise, since the address area 104 on the first storage layer 10 has continuous storage areas 114, the light beam 12f projected onto the second storage layer 8 after passing through the address area 104 has a greater intensity than the light beam projected onto the second storage layer 8 after passing through the address area in the case where there are no continuous storage areas 114. Therefore, as to the optical disk 101, the intensity of the light beam 12f projected onto the second storage layer 8 after passing through an address area 104 on the first storage layer 10 can be made closer to the intensity of the light beam 12e projected onto the second storage layer 8 after passing through the non-address area 105 on the first storage layer 10. As a result, as to the optical disk 101 employing a lumped address scheme, the light beam intensity on the second storage layer 8 can be retained at a substantially constant value regardless of whether the light is the light beam 12e passing through the non-address area 105 on the first storage layer 10 or the light beam 12f passing through the address area 104 on the first storage layer 10, enabling stable and desirable read/write on the second storage layer 8. Besides, on the optical disk 101 of the present embodiment, a continuous storage area 114 appears on alternate address tracks 113 in relation to a diameter of the optical disk 101. Therefore, when the light beam 12 is focused on the second storage layer 8 as shown in FIG. 22, in the case where a beam spot 115 formed by the light beam 12 forms on the first storage layer 10 as shown in FIG. 21, the sum of the areas of the recording marks 111 included in the area of the beam spot 115 in the non-address area 105 on the first storage layer 10 is substantially equal to the sum of the continuous storage areas 114 included in the area of the beam spot 115 in the address area 104. Thus, the intensity of the light beam 12f projected onto the second storage layer 8 after passing through an address area 104 on the first storage layer 10 can be made substantially equal to the intensity of the light beam 12e projected onto the second storage layer 8 after passing through the non-address area 105 on the first storage layer 10. In FIG. 21, ten address pits 112 are shown forming an address track 113. However, FIG. 21 is only a schematic figure, and in practice, an address track 113 is made up of 1000 or more address pits 112 of various lengths. The continuous storage area 114 on the optical disk 101 may be formed prior to the shipment of the optical disk 101 or by the optical-disk-read/write apparatus 31 based on reproduced address information when the optical disk 101 is loaded in the optical-disk-read/write apparatus 31. In the arrangement, the optical disk 101 does not need any particular arrangement that enables the determination whether to form a continuous storage area 114 in the address track 113. To implement the actions, the signal processing and controlling unit 35 in the optical-disk-read/write apparatus 31 has a recorded/unrecorded switching circuit 121 and an illuminating-unit-controlling circuit 122 as shown in FIG. 24. The illuminating unit controlled by the illuminating-unit-controlling circuit 122 is inclusive of an optical system unit 34 and a slide driving unit. In the arrangement, the signal processing and controlling unit 35 feeds a rotation synchronized signal produced in synchronism with the rotation of the optical disk 101 to the recorded/unrecorded switching circuit 121. The recorded/unrecorded switching circuit 121 checks based on the rotation synchronized signal for every turn of the optical disk 101 whether to make the address track 113 a continuous storage area 114, that is, whether to continuously recorded the address track 113. Here, as mentioned earlier, the check is done so that alternate address tracks 113 are continuous storage areas 114. If the address track 113 is caused to be a continuous storage area 114, the recorded/unrecorded switching circuit 121 feeds an address-track-continuous-recording-instructing signal to the illuminating-unit-controlling circuit 122. Upon receiving the signal, the illuminating-unit-controlling circuit 122 controls the illuminating unit and continuously record the address track 113. Meanwhile, if the address track is caused to be unrecorded, the recorded/unrecorded switching circuit 121 feeds an address-track-normal-reading-instructing signal to the illuminating-unit-controlling circuit 122. Upon receiving the signal, the illuminating-unit-controlling circuit 122 controls the illuminating unit so as to read the address track 113 at a laser intensity which is incapable of recording data. In this case, address information is reproduced. In addition, to implement the actions, the signal processing and controlling unit 35 in the optical-disk-read/write apparatus 31 may include an arrangement shown in FIG. 25 which differs from the arrangement in FIG. 24. In that arrangement, the signal processing and controlling unit 35 has a subsequent-address-track-recorded/unrecorded checking circuit 123 and the illuminating-unit-controlling circuit 122. In this arrangement, the subsequent-address-track-recorded/unrecorded checking circuit 123 determines based on the address information obtained from the address area 104 whether to make the address track 113 a continuous storage area 114. In other words, as mentioned in the foregoing, in the case where alternate address tracks 113 are designated as continuous storage areas 114, regardless whether to make the currently scanned address track 113 a continuous storage area 114, that address track 113 is read first of all, and it is determined based on the obtained address information whether to make a subsequent address track 113 a continuous storage area 114. In the arrangement, in the signal processing and controlling unit 35, the illuminating-unit-controlling circuit 122 controls the illuminating unit so as to first read that address track 113 with which the process is started and obtain an address information reproduction signal of the address track 113. The address information reproduction signal is fed to the subsequent-address-track-recorded/unrecorded checking circuit 123. Upon receiving the address information reproduction signal, the subsequent-address-track-recorded/unrecorded checking circuit 123 based on that signal determines whether to make a subsequent address track a continuous storage area 114. If the subsequent address track 113 is to be continuously recorded, the subsequent-address-track-recorded/unrecorded checking circuit 123 transmits a subsequent-address-track-continuous-recording-instructing signal to the illuminating-unit-controlling circuit 122. Upon receiving the signal, the illuminating-unit-controlling circuit 122 controls the illuminating unit so as to make the subsequent address track 113 a continuous storage area 114. Meanwhile, if the subsequent address track 113 is to be unrecorded, the subsequent-address-track-recorded/unrecorded checking circuit 123 feeds a subsequent address-track-normal-reading-instructing signal to the illuminating-unit-controlling circuit 122. Upon receiving the signal, the illuminating-unit-controlling circuit 122 controls the illuminating unit so as to read the address track 113 at a laser intensity which is incapable of recording data. In the arrangement in FIG. 24, if the process of forming a continuous storage area 114 in the address area 104 is suspended before completion and resumed again thereafter, it is unknown whether the last address track 113 processed before the suspension is now a continuous storage area 114 or not. Therefore, adjacent address tracks 113 are possibly both continuous storage areas 114. In contrast, such situations are prevented from happing in the arrangement in FIG. 25, the address information is being always checked to determine whether to make the subsequent address track 113 continuously recorded or unrecorded at all. [Embodiment 5] The following will describe another embodiment of the present invention in reference to FIG. 26 and FIG. 27. An optical disk 131 of the present embodiment has a judgement mark area 132 between a non-address area 105 and the head of an address area 104 as shown in FIG. 26 which is an enlarged view around the head of the address area 104. In the judgement mark area 132 there are formed judgement pits (judgement marks) 133, 134 by which it is determined whether the address track 113 in the address area 104 is made a continuous storage area 114 or not. The judgement pits 133, 134 are located between the guiding groove 13 in a non-address area 105 and its succeeding address track 113 in the address area 104. The judgement pits 133 show that the address tracks 113 are not to be made continuous storage areas 114 and are positioned in the judgement mark area 132 near the non-address area 105. Meanwhile, the judgement pits 134 show that the address tracks 113 are to be made continuous storage areas 114 and are positioned in the judgement mark area 132 near the address area 104. The judgement pits 133 exist at positions shifted along the tracks when compared to the judgement pits 134. In the present embodiment, as mentioned earlier, alternate address tracks 113 are made continuous storage area 114; therefore, the judgement pits 133, 134 appear alternately along a diameter of the optical disk 131. To appropriately make the address tracks 113 in the address area 104 continuous storage areas 114 using the judgement pits 133, 134, the signal processing and controlling unit 35 in the optical-disk-read/write apparatus 31 is provided with a recorded/unrecorded-checking circuit 124 and the illuminating-unit-controlling circuit 122 as shown in FIG. 27. In the arrangement, upon detecting a judgement mark reproduction signal which is a signal reproduced from the judgement pits 133, 134, the signal processing and controlling unit 35 feeds that signal to the recorded/unrecorded-checking circuit 124. Based on the judgement mark reproduction signal, the recorded/unrecorded-checking circuit 124 determines whether or not the address tracks 113 associated with the judgement pits 133, 134 are to be made continuous storage areas 114. To make an address track 113 a continuous storage area 114, the recorded/unrecorded-checking circuit 124 feeds an address-track-continuous-recording-instructing signal to the illuminating-unit-controlling circuit 122. Upon receiving the signal, the illuminating-unit-controlling circuit 122 controls the illuminating unit so as to make the associated address track 113 a continuous storage area 114. Meanwhile, to not make an address track 113 a continuous storage area 114 (to make the address track 13 unrecorded), the recorded/unrecorded-checking circuit 124 fees an address-track-normal-reading-instructing signal to the illuminating-unit-controlling circuit 122. Upon receiving the signal, the illuminating-unit-controlling circuit 122 controls the illuminating unit so as to read the address track 113 at a laser intensity which is incapable of recording data. As mentioned in the foregoing, as to the optical disk 131 of the present embodiment, it can be immediately determined owning to the judgement pits 133, 134 in the judgement mark area 132 whether to make an address track 113 in the address area 104 a continuous storage area 114. Therefore, the processing velocity of the optical-disk-read/write apparatus 31 can be increased without reading the address track 113 in the address area 104, i.e., address information. [Embodiment 6] The following will describe another embodiment of the present invention in reference to FIGS. 28–31. As shown in FIG. 28, an optical disk 141 of the present embodiment is readable/writeable on both a groove 142 and a land 143 which are formed alternately as viewed along a diameter of the optical disk 141 in the non-address area 105. The groove 142 and land 143 are spiral and recording marks 111 are formed on the groove 142 and land 143 by projection of a light beam 12. The address area 104 is made up of a first address area 144 and a second address area 145 which are adjacent to each other along tracks. In the first address area 144 constituting a head part of the address area 104, there are formed first address pits 146 along imaginary lines extending from the groove 142. In the second address area 145 constituting the tail part of the address area 104, there are formed second address pits 147 along imaginary lines extending from the land 143. Relatively shifting the positions of the first address area 144 and the second address area 145 along the tracks so that they do not overlap in a direction normal to the tracks eliminates crosstalk in signals reproduced from the first and second address pits 146, 147. The positions of the first address area 144 and the second address area 145 may be reversed. In addition, some of the address tracks 113 in the address area 104 extend from the groove 142, while the others extend from the land 143. In the present embodiment, those address track 113 extending from the groove 142 are made continuous storage areas 114. In addition, the address track 113 is formed in both the first address area 144 and the second address area 145. Those address tracks 113 extending from the groove 142 have the first address pits 146 in the first address area 144, and those extending from the land 143 have the second address pits 147 in the second address area 145. As mentioned in the foregoing, as to an optical disk 141 of the present embodiment, continuous storage areas 114 are formed in those address tracks 113 extending from the groove 142, that is, in the first address area 144 and the second address area 145 of the address track 113. Therefore, like the foregoing optical disks 101, 131, to read/write the second storage layer 8, the sum of the areas of the recording marks 111 included in the area of the beam spot 115 in the non-address area 105 on the first storage layer 10 is substantially equal to the sum of the continuous storage areas 114 included in the area of the beam spot 115 in the address area 104. Thus, the intensity of the light beam 12f projected onto the second storage layer 8 after passing through an address area 104 on the first storage layer 10 can be made substantially equal to the intensity of the light beam 12e projected onto the second storage layer 8 after passing through the non-address area 105 on the first storage layer 10. As a result, as to the optical disk 141 employing a lumped address scheme, the light beam intensity on the second storage layer 8 can be retained at a substantially constant value regardless of whether the light is the light beam 12e passing through the non-address area 105 on the first storage layer 10 or the light beam 12f passing through the address area 104 on the first storage layer 10, enabling stable and desirable read/write on the second storage layer 8. In the present embodiment, the continuous storage area 114 is supposed to be formed in those address tracks 113 which extend from the groove 142. The present embodiment is not limited by this: the continuous storage area 114 may be formed in those address tracks 113 which extend from the land 143. In addition, as in previous cases, the continuous storage area 114 may be formed prior to the shipment of the optical disk 141 or by using the optical-disk-read/write apparatus 31 after shipment. If the optical-disk-read/write apparatus 31 is used to from an continuous storage area 114, the aforementioned methods are all applicable. Further, to form a continuous storage area 114, the signal processing and controlling unit 35 may have a land/groove determining circuit 125 and the illuminating-unit-controlling circuit 122 as shown in FIG. 29. In this arrangement, for example, it is determined whether the track currently being scanned is the groove 142 or the land 143, and those address tracks 113 which extend from either the groove 142 or the land 143 in the address area 104 are made continuous storage areas 114 according to a result of the determination. In the arrangement, the land/groove determining circuit 125 determines whether the track currently being scanned is the groove 142 or the land 143 from a tracking servo signal or an address information reproduction signal. If the determination turns out that it is the groove 142, the land/groove determining circuit 125 feeds an address-track-continuous-recording-instructing signal to the illuminating-unit-controlling circuit 122 to make an address track 113 a continuous storage area 114. Upon receiving the signal, the illuminating-unit-controlling circuit 122 controls the illuminating unit so as to make an address track 113 which extends from the groove 142 a continuous storage area 114. Meanwhile, if the determination turns out that it is the land 143, the recorded/unrecorded-checking circuit 124 feeds an address-track-normal-reading-instructing signal to the illuminating-unit-controlling circuit 122. Upon receiving the signal, the illuminating-unit-controlling circuit 122 controls the illuminating unit so as to read the address track 113 at a laser intensity which is incapable of recording data. In addition, as to the optical disk 141, as shown in FIG. 30, the continuous storage area 114 may be formed in the second address area 145 in those address tracks 113 which extend from the groove 142, in the first address area 144 in those address tracks 113 which extend from the land 143, and in each address track 113. The first address area 144 and the second address area 145 may be reversed in position. Further, the continuous storage area 114 may be formed only at places where the first address pit 146 and the second address pit 147 are provided, conversely to the formation places in FIG. 30. In the arrangement, like the foregoing cases, the intensity of the light beam 12f projected onto the second storage layer 8 after passing through an address area 104 on the first storage layer 10 can be made substantially equal to the intensity of the light beam 12e projected onto the second storage layer 8 after passing through the non-address area 105 on the first storage layer 10. As a result, as to an arrangement employing a lumped address scheme, the light beam intensity on the second storage layer 8 can be retained at a substantially constant value, enabling stable and desirable read/write on the second storage layer 8. Likewise, the continuous storage area 114 may be formed in advance, before the optical disk 141 is shipped or by using the optical-disk-read/write apparatus 31 when the optical disk 141 is loaded into the optical-disk-read/write apparatus 31. The aforementioned methods are all applicable in these cases. For example, the continuous storage area 114 may be formed based on reproduced address information or whether the track being scanned is the groove 142 or the land 143. To implement the actions, the signal processing and controlling unit 35 in the optical-disk-read/write apparatus 31 is equipped with, for example, an address-information-presence-checking circuit 126 and the illuminating-unit-controlling circuit 122 as shown in FIG. 31. In the arrangement, the signal processing and controlling unit 35 feeds an address information signal reproduced from the address area 104 to the address-information-presence-checking circuit 126 where the address-information-presence-checking circuit 126 determines whether the input signal is carrying address information. If the determination turns out that no address information is present, the address-information-presence-checking circuit 126 feeds an address-track-continuous-recording-instructing signal to the illuminating-unit-controlling circuit 122 to make an area where address information is missing for the address track 113, that is, an area of the first address area 144 or the second address area 145, a continuous storage area 114. Upon receiving that signal, the illuminating-unit-controlling circuit 122 controls the illuminating unit so as to form a continuous storage area 114 in an area where there is no address information for the address track 113. Meanwhile, if address information is present, the address-information-presence-checking circuit 126 controls the illuminating unit and reads the address track 113 at a laser intensity which is incapable of recording data, so that no continuous storage area 114 is formed in an area where address information is present for the address track 113. In this and foregoing embodiments, if the optical-disk-read/write apparatus 31 is used to form the continuous storage area 114 on an optical disk, the cost of the optical disk can be reduced by reducing the manufacturing steps of the optical disk. In addition, in this and foregoing embodiments, the optical disks were supposed to be high-to-low phase change types of storage media such that the interval areas between recording marks 111 exhibit a higher reflectance, i.e., a lower transmittance, than the recording mark 111 in the first storage layer 10 and the second storage layer 8. The foregoing arrangements are applicable even when the optical disks are low-to-high phase change types of storage media such that the interval areas exhibit a lower reflectance, i.e., a higher transmittance, than the recording marks 111. [Embodiment 7] The following will describe an embodiment of the present invention in reference to FIG. 62 and FIG. 63. Referring to FIG. 63, an optical disk (optical storage medium) 201 of the present embodiment has a center hole 202 at its center and a recordable area 203 outside the center hole 202 in relation to a diameter. As shown in FIG. 35 and FIG. 36, in the recordable area 203, a spiral (or concentric) read/write guiding groove G is formed in a guiding-groove-and-pits-formed layer 212 and a guiding-groove-and-pits-formed intermediate layer 214 along which information can be read/written. In addition, an innermost part 204 is formed around the center hole 202 and an outermost part 205 is formed near the circumference of the optical disk 201. The optical disk 201 has prepit areas 206 made up of an inner prepit area 206a and an outer prepit area 206b. The inner prepit area 206a is provided adjacently outside the innermost part 204, and the outer prepit area 206b is provided adjacently inside the outermost part 205. As shown in FIG. 37, in the prepit area 206, pits P are arranged forming a spiral (or concentric circles) in the guiding-groove-and-pits-formed layer 212 and the guiding-groove-and-pits-formed intermediate layer 214. Prepit information is read from the pit row of the pits P. In the pit row, typically, the writing power, reading power, and other kinds of information on the optical disk 201 is prerecorded in the concave or convex form (not shown) of the pits P. As shown in FIG. 34 which is a vertical cross-sectional view of the optical disk 201, the optical disk 201 is structured from the guiding-groove-and-pits-formed layer 212, a second storage layer (last data storage layer) 213, the guiding-groove-and-pits-formed intermediate layer 214, a first storage layer (light-striking-side storage layer) 215, and a surface-coating layer 216, with the layers sequentially stacked on a disk substrate 211. To read/write the first storage layer 215 and the second storage layer 213 on the optical disk 201, a light beam 217 projected from one side of the disk, i.e., the side on which the surface-coating layer 216 exists, is concentrated on the first and second storage layers 215, 213. FIG. 35 shows the arrangement of the optical disk 201 in more detail. In FIG. 35, the disk substrate 211 is made of, for example, a 1.2-mm thick, transparent polycarbonate substrate. The guiding-groove-and-pits-formed layer 212 is made of, for example, a 20-micron thick, ultraviolet-ray-setting resin layer and formed, for example, by a pattern transfer technology termed 2P method. On one of the surfaces of the guiding-groove-and-pits-formed layer 212 which is closer to the second storage layer 213, the guiding groove G is provided in the recordable area 203 and the pits P (not shown in FIG. 35) are provided in the prepit area 206. The second storage layer 213 includes, for example, an AlTi-alloy reflective film 213a, a ZnS—SiO2 interference film 213b, a SiN protective film 213c, a GeSbTe phase change recording layer 213d, a SiN protective film 213e, and a ZnS—SiO2 interference film 213f. These films are formed as they are sequentially deposited on the guiding-groove-and-pits-formed layer 212 by means of sputtering. Like the guiding-groove-and-pits-formed layer 212, the guiding-groove-and-pits-formed intermediate layer 214 is made of, for example, a 20-micron thick, ultraviolet-ray-setting resin layer and formed by, for example, a pattern transfer technology termed 2P method. On one of the surfaces of the guiding-groove-and-pits-formed intermediate layer 214 which is closer to the first storage layer 215, the guiding groove G is provided in the recordable area 203 and the pits P (not shown in FIG. 35) are provided in the prepit area 206. Like the second storage layer 213, the first storage layer 215 includes. for example, a ZnS—SiO2 interference film 215a, a SiN protective film 215b, a GeSbTe phase change recording layer 215c, a SiN protective film 215d and a ZnS—SiO2 interference film 215e. The first storage layer 215 is formed by sequentially depositing these films on the guiding-groove-and-pits-formed intermediate layer 214 by means of sputtering. The surface-coating layer 216 is made of, for example, a 80-micron thick, ultraviolet-ray-setting resin layer, and formed by spin coating the first storage layer 215 with an ultraviolet-ray-setting resin and setting the resin by the projection of ultraviolet rays. The optical disk substrate 211 is, as mentioned in the foregoing, a substrate made of a transparent polycarbonate. However, when a light beam 217 is incident to the surface-coating layer 216 as is the case with the optical disk 201 of the present embodiment, the disk substrate 211 does not need be transparent, and may be an opaque, metallic substrate. In addition, the optical disk 201 of the present embodiment is provided with the guiding-groove-and-pits-formed layer 212 and the guiding-groove-and-pits-formed intermediate layer 214 which are formed by 2P method and which have the guiding groove G and the pits P. However, a disk substrate 211 provided on its surface directly with a guiding groove G and pits P may be formed by, for example, injection molding. The structure including the disk substrate 211 does not require the guiding-groove-and-pits-formed layer 212 and the guiding-groove-and-pits-formed intermediate layer 214. In addition, although the surface-coating layer 216 is formed on the first storage layer 215 by spin coating, the layer 216 may be provided instead in the form of uniformly thick, transparent sheet pasted on the first storage layer 215. In addition, the optical disk 201 has a structure including the guiding-groove-and-pits-formed layer 212, the second storage layer 213, the guiding-groove-and-pits-formed intermediate layer 214, the first storage layer 215, and the surface-coating layer 216 sequentially stacked on the optical disk substrate 211. This is not the only option available. For example, the optical disk 201 may be structured so that it includes the guiding-groove-and-pits-formed layer 212, the first storage layer 215, the guiding-groove-and-pits-formed intermediate layer 214, the second storage layer 213, and the surface-coating layer 216 sequentially stacked on the optical disk substrate 211, with the light beam 217 projected onto the optical disk substrate 211 as shown in FIG. 38. In this structure, the films constituting the first storage layer 215 and the second storage layer 213 are in the reverse order to those shown in FIG. 35. An optical-disk-read/write apparatus (optical read/write apparatus) which reads/writes on the optical disk 201 was, as with the optical disk 1, described in reference to FIG. 5. In the present embodiment, the optical-disk-read/write apparatus 31 reads from, or writes into, the second storage layer 213 after the recordable area 203 of the first storage layer 215 is fully recorded. The operations in this case are carried out under the control of the signal processing and controlling unit 35 on the optical system unit (illuminating means) 34 and the slide driving unit (illuminating means). In the foregoing situation, the following will describe how the optical-disk-read/write apparatus 31 reads/writes on the optical disk 201, supposing that data, is recorded in the first storage layer 215 of the optical disk 201, starting with the inner prepit area 206a in the recordable area 203 until data fills part of the recordable area 203 of the first storage layer 215, and then the operation moves to reading/writing in the second storage layer 213. It is also supposed that the optical disk 201 is a high-to-low medium such that the interval area is more reflective than the recording mark area and data is recorded by phase change. As a result of recording in the first storage layer 215, as shown in FIG. 39 and FIG. 40, a recorded part 203a1 (shown by hatched lines) is produced covering the inner prepit area 206a of the recordable area 203 of the first storage layer 215 up to partway of the recordable area 203. Here, the first storage layer 215 is more optically transmissive than in the recorded part 203a1 than other areas. As a result, the light beam 217 projected on the second storage layer 213 is more intense when it is concentrated on the second storage layer 213 if the light beam 217 (light beam 217b) has passed through the recorded part 203a1 than if the light beam 217 (light beam 217a) has passed through an area other than the recorded part 203a1 (non-recorded area). In other words, in recording data into the second storage layer 213, the light beam 217 varies in intensity when it reaches the second storage layer 213 after passing through the first storage layer 215, depending on whether it has come through the recorded part 203a1. In this case, to record data into the second storage layer 213, a complex write system is required which can vary the light beam 217 in intensity depending on whether there are any records stored in the first storage layer 215. A similar difference develops in intensity of the light beam 217, and a similarly complex read system is required when data is read from the second storage layer 213, because the return light reflected off the second storage layer 213 changes in quantity depending on whether the light beam 217 has passed through the recorded part 203a1 of the first storage layer 215. Accordingly, in the optical-disk-read/write apparatus 31 of the present embodiment, as shown in FIG. 41, data is read/write from/into the second storage layer 213 only after the recordable area 203 of the first storage layer 215 is fully recorded. In other words, to record on the optical disk 201, the optical-disk-read/write apparatus 31 first writes data in the first storage layer 215, and only after the recordable area 203 of the first storage layer 215 is recorded to its full capacity, starts writing or reading data into/from the second storage layer 213. The operation ensures that in the read/write operation as to the second storage layer 213, the light beam 217 projected on the second storage layer 213 always passes through the fully recorded, first storage layer 215 before entering the second storage layer 213. In both read and write operations, the light beam 217 has a constant intensity when it reaches the second storage layer 213, which eliminates the need to use a complex read/write system to control the intensity of the light beam 217. Stable read/write operations are thus achieved. FIG. 62 shows the first storage layer 215 and the second storage layer 213 near the periphery of the optical disk 201 in their initial states. On the optical disk 201, the first storage layer 215 has an unrecorded recordable area 203a and a blank area 205a constituting the outermost part 205, and the second storage layer 213 has an unrecorded recordable area 203b, an outer prepit area 206a, and a blank area 205b constituting the outermost part 205. In this situation, the blank areas 205a, 205b are those areas where no guiding groove G or pits P are formed. The innermost part 204 of the first and second storage layers 215, 213 also has similar blank areas (not shown). The optical disk 201 in this state exhibits uniform transmittance, since the recordable area 203aof the first storage layer 215 is unrecorded. Therefore, when prepit information is reproduced by concentrating the light beam 217 on the outer prepit area 206b of the second storage layer 213, the intensity of the reproduction signal does not vary. In addition, since the prepit area 206 is provided to the second storage layer 213, the second storage layer 213 is stably readable/writeable without being affected by the prepit area 206. Next, as shown in FIG. 42, writing in a part of the unrecorded recordable area 203a produces a recorded part 203a1 and leaves the other part as a non-recorded part 203a2. In this case, as shown in FIG. 43, in the recorded part 203a1, recording marks M with reduced transmittance are formed in the guiding groove G. In the non-recorded part 203a2, no recording marks M are formed and the transmittance remains unchanged. Therefore, the light beam 217c having passed through the recorded part 203a1 differs in intensity from the light beam 217d having passed through the non-recorded part 203a2. The reproduction signal of prepit information therefore differs in intensity between the light beams 217c and 217d. In addition, as to the optical disk 201, typically, it is impossible to completely match the center of the spiral guiding groove G on the first storage layer 215 and the center of the spiral pit row on the second storage layer 213. Therefore, when the light beam 217e illuminates both a part of the recorded part 203a1 and a part of the non-recorded part 203a2 before being concentrated on the outer prepit area 206b of the second storage layer 213 as shown in FIG. 42, the boundary between the recorded part 203a1 and the non-recorded part 203a2 moves in the light beam 217e with the rotation of the optical disk. Therefore, as shown in FIG. 44, the reproduction signal of the prepit information varies in intensity as the optical disk 201 rotates. FIG. 44 only shows the envelope E of the reproduction signal; the intensity of the reproduction signal is shown on the axis of ordinates and the angular position of the rotating optical disk 201 is shown on the axis of abscissas. FIG. 45 shows with the angle axis enlarged the reproduction signal S1 of prepit information at the 0-degree angular position of FIG. 44 and the reproduction signal S2 of prepit information at the 180-degree angular position of FIG. 44. To convert the reproduction signals S1, S2 into digital signals, detection needs to carried out with the slice levels set to the mean levels to of the reproduction signals S1, S2. However, comparing the reproduction signal S1 with the reproduction signal S2 will show that the mean levels differ greatly, which makes it impossible to carry out detection using a single slice level. The problem can be solved by detecting the upper envelope E1 and lower envelope E2 which constitute the envelope E of the reproduction signal and setting the variable slice level Lv to their mean levels as shown in FIG. 46. FIG. 47 shows the configuration of a reproduction circuit producing a digital signal from the slice level Lv. The reproduction circuit includes an envelope detecting circuit 251, a slice level producing circuit 252, and a comparator 253. The envelope detecting circuit 251 as envelope detecting means is made of, for example, a peak-hold circuit and a bottom-hold circuit; the peak-hold circuit detects the upper envelope E1 and the bottom-hold circuit detects the lower envelope E2. The slice level producing circuit 252 as mean level producing means produces a slice level Lv by outputting a mean value of values of the detected upper and lower envelopes E1, E2. The slice level producing circuit 252 is made of, for example, an operation circuit including an adder circuit for adding the values of the envelopes E1, E2 and a divider circuit for dividing the sum by 2. The comparator 253 as digital converting means compares the reproduction signal with the slice level Lv produced by the slice level producing circuit 252 and converts the reproduction signal to a binary digital signal. For example, the comparator 253 produces a 1 for output when the reproduction signal is above the slice level Lv and a 0 for output when the reproduction signal is below the slice level Lv. In the reproduction circuit thus configured, the reproduction signal is fed to the envelope detecting circuit 251 and the comparator 253. The envelope detecting circuit 251 detects the upper envelope signal E1 and the lower envelope E2 of the reproduction signal. The slice level producing circuit 252 produces slice levels Lv from the envelope E1, E2. The comparator 253 produces a digital signal by comparing the reproduction signal with the slice level Lv. In addition, FIG. 48 shows the relationship between the reproduction signal intensity and the angular position of the optical disk 201, as to the method to produce a digital signal from a reproduction signal by means of the reproduction circuit shown in FIG. 49. The reproduction circuit in FIG. 49 includes a high-pass filter 261, a slice level producing circuit 262, and a comparator 263. The high-pass filter 261 as low frequency variation removing means removes low frequency variations from a reproduction signal and passes high frequency components. The slice level producing circuit 262 produces a slice level of a constant voltage. The comparator 263 as digital converting means compares the reproduction signal transmitted through the high-pass filter 261 to the slice level as is the case with the comparator 253 and converts into binary digital signal. In the reproduction circuit thus configured, the incoming reproduction signal is first stripped of its low frequency variations by the high-pass filter 261. The reproduction signal, before being fed to the high-pass filter 261, includes low frequency variations, and therefore the mean level of the envelope E changes as shown in FIG. 46. However, the reproduction signal is past through the high-pass filter 261, and the mean level of the envelope E becomes constant regardless of the angle as shown in FIG. 48. The comparator 263 compares the reproduction signal past through the high-pass filter 261 with the constant slice level Lc fed from the slice level producing circuit 262 and produces a digital signal. Although the reproduction circuit and the slice level producing circuit 262 produce the slice level Lc in the foregoing, the slice level Lc may be set to 0 volts, because the mean levels of the upper envelope E1 and the lower envelope E2 are normally equal to 0 volts as the reproduction signal passes through the high-pass filter 261. Therefore, in this case, the slice level producing circuit 262 can be omitted. As described in the foregoing, the provision of the prepit area 206 in the second storage layer 213 enables the optical disk 201 to read/write data from/into the second storage layer 213 without changing the read/write sensitivity of the recordable area 203. In addition, the use of the reproduction circuit shown in FIG. 47 or FIG. 49 ensures that a digital signal is derived stably from a reproduction signal, even if the reproduction signal of prepit information varies in intensity with the rotation of the optical disk 201 provided that the light beam 217e illuminates both the recorded part 203a1 and the non-recorded part 203a2 before being focused on the outer prepit area 206b of the second storage layer 213. However, as mentioned earlier, the non-recorded part 203a2 exhibits a lower transmittance than the recorded part 203a1. When data is to be read from the prepit area 206 including the outer prepit area 206b using the light beam 217d traveling through the non-recorded part 203a2 of the first storage layer 215, as could be understood from FIG. 46 and FIG. 48, the reproduction signal has so small an amplitude that the prepit information cannot be reproduced stably. Accordingly, preferably, the part of the first storage layer 215 through which the light beam 217e is transmitted is fully recorded and thus exhibits a relatively high transmittance. FIG. 50 shows a structure of the optical disk 201 capable of increasing the amplitude of the reproduction signal obtained from prepit area 206 (not shown except the outer prepit area 206b) on the second storage layer 213. The optical disk 201 has a pseudo-recording area 207 interposed between the recordable area 203a and the blank area 205a. The pseudo-recording area 207 is provided in a part of the first storage layer 215 which corresponds to the prepit area 206 of the first storage layer 215 and stores pseudo information in advance. In the pseudo-recording area 207, as in the recordable area 203, the transmittance lowers where recording marks M are formed in the guiding groove G as shown in FIG. 51. Thus, the pseudo-recording area 207 has as high a transmittance as the recordable area 203, and the light beam 217 passing through the pseudo-recording area 207 comes to have a high intensity. Thus, the amplitude of the reproduction signal of the prepit area 206 on the second storage layer 213 can be increased. The recording marks M formed on the pseudo-recording area 207 differ from those formed on the recordable area 203; the former include no main recording information, but pseudo recording information. As pseudo recording information, no particular information needs be recorded, but nonsense or meaningless information may be recorded. Alternatively, if the pseudo-recording area 207 is to be formed in advance prior to the shipment of the optical disk 201, identification information, encryption information, and other kinds of information may be recorded in the pseudo-recording area 207 which is unique to individual optical disks 201. In this situation, as shown in FIG. 50, preferably, the pseudo-recording area 207 is formed so that the light beams 217f, 217g always travel through the pseudo-recording area 207 of the first storage layer 215 even when data is read from the edges of the prepit area 206b of the second storage layer 213 in relation to the radius direction of the disk. Accordingly, the pseudo-recording area 207 is provided covering a wider area than the outer prepit area 206b of the second storage layer 213. For example, supposing the first storage layer 215 is separated from the second storage layer 213 by a distance of 20 microns, the light beam 217 focused on the second storage layer 213 forms on the first storage layer 215 a spot having a radius of about 10 microns. Therefore, the pseudo-recording area 207 needs be formed at least about 10 microns wider than both ends of the prepit area 206 of the second storage layer 213. In addition, when the center of the guiding groove G formed on the first storage layer 215 does not match the center of the pit row formed on the second storage layer 213, hence eccentricity exists between the two centers, the pseudo-recording area 207 needs be widened by an amount equivalent to the eccentricity. For this reason, the pseudo-recording area 207 is preferably formed about 100 microns wider than both ends of the prepit area 206 of the second storage layer 213. FIG. 50 shows an example in which the pseudo-recording area 207 is provided in the outer prepit area 206b. A similar pseudo-recording area may be provided in the inner prepit area 206a too. In this situation, the pseudo-recording area 207 may be either formed prior to the shipment of the optical disk 201 or formed by the optical-disk-read/write apparatus 31 when an unused optical disk 201 is loaded in the optical-disk-read/write apparatus 31 for replay or recording. The provision of the pseudo-recording area 207 using an optical-disk-read/write apparatus eliminates the need to provide the pseudo-recording area 207 prior to the shipment of the optical disk, which enables reduction of the cost of the optical disk. FIG. 52 shows a configuration of pseudo recording circuit provided in the optical-disk-read/write apparatus 31 to form a pseudo-recording area 207. The configuration includes the aforementioned pseudo-recording-status-checking circuit 271 in the signal processing and controlling unit 35. The pseudo-recording-status-checking circuit 271 as recording status checking means checks, based on the reproduction signal produced by a light-receiving element 47 from the reflection off the pseudo-recording area 207, whether the pseudo-recording area 207 already contains pseudo recording information. The pseudo-recording-status-checking circuit 271 includes a comparator and other circuits to check and determine whether the pseudo-recording area 207 contains any records, in accordance with whether or not the reproduction signal which represents the quantity of light reflected off the pseudo-recording area 207 exceeds a predetermined threshold value. In the arrangement, the pseudo-recording area 207 is read immediately after the optical disk 201 is loaded in the optical-disk-read/write apparatus 31. The pseudo-recording-status-checking circuit 271 checks based on the reproduction signal whether the pseudo-recording area 207 is fully recorded or not. If the pseudo-recording area 207 is not fully recorded, the pseudo-recording-status-checking circuit 271 regards the optical disk 201 as being never used, and feeds a pseudo writing-instruction signal to the illuminating-unit-controlling circuit 36 as pseudo-recording means provided in the signal processing and controlling unit 35. As a result, pseudo information is recorded in the pseudo-recording area 207 of the first storage layer 215 under the control of the illuminating-unit-controlling circuit 36. Meanwhile, if the pseudo-recording area 207 is fully recorded, the pseudo-recording-status-checking circuit 271 regards the loaded optical disk 201 as having been used, and feeds an ordinary writing-instruction signal to the illuminating-unit-controlling circuit 36. As a result, an ordinary recording operation is performed as to the optical disk 201 under the control of the illuminating-unit-controlling circuit 36. Next, the following description will describe an optical disk 201 in which the first storage layer 215 has a prepit area 206. As a comparative example, an optical disk 281 is first described with which no consideration is given to the read/write sensitivity of the second storage layer 215. With the optical disk 281, as shown in FIG. 53, a blank area 205a of the first storage layer 215 is provided in the same range as a blank area 205b of the second storage layer 213. In the first storage layer 215, an outer prepit area 206b is provided between the recordable area 203a and the blank area 205a. In addition, an inner prepit area 206a (not shown) is also provided on the first storage layer 215. Since the prepit area 206 is located on the light-striking side of the optical disk 281 thus structured, the reproduction signal derived from the prepit area 206 never varies in intensity. The optical disk 281 is free from the problem that the reproduction signal derived from the prepit area 206 varies in intensity as shown in FIG. 42. However, the provision of the prepit area 206 on the first storage layer 215 causes the same problem as with the conventional optical disk (see FIG. 70). Concretely, the first storage layer 611 exhibits different optical transmittances between the recordable area 603 and the prepit area 606, resulting in variations in read/write sensitivity of the second storage layer 612. Now, the variations in recording sensitivity of the optical disk 281 are elaborately described. As to the optical disk 281, the recordable area 203a of the first storage layer 215 is first fully recorded by a recording operation of the optical-disk-read/write apparatus 31. In this situation, the fully recorded, recordable area 203a includes high-transmittance recording marks M, and the light beam 217h concentrated on the second storage layer 213 after passing through the recordable area 203a exhibits a relatively high intensity. Meanwhile, the light beam 217i concentrated on the second storage layer 213 after passing through the prepit area 206 with no recording marks M exhibits a relatively low intensity. Next, to record data in the recordable area 203b of the second storage layer 213, the light beam 217h and the light beam 217i, although originally of the same intensity, differs in intensity when they reach the second storage layer 213. Therefore, the recording sensitivity varies depending upon where recording takes place, which makes it extremely difficult to perform stable recording. Further, if a light beam passes through a boundary between the fully recorded recordable area 203a and the prepit area 206 before concentrated on the second storage layer 213, since there exists eccentricity which is defined as the displacement in position between the center of the guiding groove G on the first storage layer 215 and the center of the guiding groove G on the second storage layer 213, the recording sensitivity undesirably varies with rotation of the optical disk 281. By contrast, the optical disk 201 shown in FIG. 54 provides means to solve these problems by expanding the blank area 205b. The following will describe such an optical disk 201. As to the optical disk 201 shown in FIG. 54, the blank area 205b the second storage layer 213 is expanded inwards, and a light beam 217j entering the optical disk 201 always passes through the fully recorded recordable area 203a of the first storage layer 215 before concentrated on the second storage layer 213. In this manner, as to the optical disk 201, the recordable area 203a of the first storage layer 215 is formed wider than the recordable area 203b of the second storage layer 213, and the prepit area 206 is formed along the outer circumference of the recordable area 203a. The configuration makes the intensity of the light beam 217j always constant on the second storage layer 213 and thus achieves stable recording to the second storage layer 213 and stable reproduction of prepit information from the first storage layer 215. Now, it will be described how much wider the recordable area 203a of the first storage layer 215 should be than the recordable area 203b of the second storage layer 213. Assuming that the first storage layer 215 is separated from the second storage layer 213 by a distance of 20 microns, the light beam 217j focused on the second storage layer 213 forms on the first storage layer 215 a spot having a radius of about 10 microns. Therefore, the recordable area 203b needs be formed at least about 10 microns wider than the width of the recordable area 203a. In addition, when the center of the guiding groove G formed on the first storage layer 215 does not match the center of the guiding groove G formed on the second storage layer 213, hence eccentricity exists between the two centers, the recordable area 203a needs be widened by an amount equivalent to the eccentricity. Therefore, in this case, the recordable area 203a is preferably formed about 100 microns wider than the width of the recordable area 203b. As to the optical disk 201, the recordable area 203b of the second storage layer 213 narrows down and the storage capacity decreases. By contrast, the optical disk 201 shown in FIG. 55 and FIG. 56 has such a structure to add to the storage capacity while preventing the prepit area 206 from reducing the recording sensitivity. The optical disk 201 has in place of the aforementioned prepit area 206 a prepit area 208 made of an inner prepit area 208a and an outer prepit area 208b, as shown in FIG. 55. The prepit area 208 has an optical transmittance which is equal to that of the fully recorded recordable area 203a of the first storage layer 215 shown in FIG. 56. As shown in FIG. 57, in the prepit area 208, alternate pit rows of pits P which are spirally (or concentrically) arranged have a continuously recorded, continuous storage area R. In the continuous storage area R, the pits P and the intervals between the pits P are continuously in the same state, i.e., have the same transmittance, as the recording marks M in the recordable area 203a. In the recorded recordable area 203a, a fully recorded portion (recording mark M) and a non-fully-recorded portions are formed alternately in the guiding groove G. In practice, the lengths of the fully recorded and non-fully-recorded portions along the guiding groove G alters depending on recording information. However, as to the guiding groove G, recording is done so that the recorded portions and the non-fully-recorded portions are formed at a substantially equal ratio. In addition, the depression area (land area) between any adjacent guiding grooves G are non-recorded areas and formed substantially as wide as the guiding groove G. Therefore, the sum of the areas of the recording marks M is equal to ¼ the net area of the recordable area 203a. Meanwhile, in the prepit area 208, the non-recorded area between any adjacent pit rows is formed substantially as wide as the diameter of the pit P. Therefore, to form a recorded portion (¼ the net prepit area 208) which has an area substantially equal to the recorded portion of the recordable area 203a, recording needs be done so that a continuous storage area R can be formed for alternate pit rows. Other than guiding groove recording schemes, to employ a land and groove recording scheme whereby recording marks M are formed not only in the guiding groove G, but also in land areas, the sum of the areas of the recording marks M formed in the recordable area 203a is ½ the net area of the recordable area 203a. Therefore, to form a recorded portion having an area substantially equal to the recorded portion (½ the net area of the prepit area 208) of the recordable area 203a, recording needs be done so that a continuous storage area R can be formed continuously along a pit row. As mentioned in the foregoing, the continuous storage area R exhibits as high an optical transmittance as the recording mark M. Therefore, as shown in FIG. 58, the fully recorded portions formed on the first storage layer 15 in the spots of a light beam 217k passing through the fully recorded recordable area 203a before being concentrated on the second storage layer 213 and a light beam 2171 passing through the outer prepit area 208b before being concentrated on the second storage layer 213 have the substantially equal areas. This makes the intensities of the light beams 217k, 217l on the second storage layer 213 substantially equal, and the second storage layer 213 no longer varies in recording sensitivity even when the prepit area 208 is provided. Therefore, expanding the recordable area 203b of the second storage layer 213 adds to the storage capacity as compared to the optical disk 201 in FIG. 54. In this situation, the blank areas 205a, 205b are unrecorded and exhibit low optical transmittance. The ends of the recordable area 203b of the second storage layer 213 therefore need be determined so that the light beam 2171 reaching the second storage layer 213 always passes through the outer prepit area 208b, as shown in FIG. 56. In this manner, as to the optical disk 201, in the prepit area 208 of the first storage layer 215, alternate pit rows have a continuous storage area R, and the outer periphery of the outer prepit area 208b is positioned further outside the outer periphery of the recordable area 203b of the second storage layer 213. In the case of the inner prepit area 208a, its inner periphery is positioned further inside the inner periphery of the recordable area 203b of the second storage layer 213. Thus, the light beams 217k, 217l always have equal intensities on the second storage layer 213. Therefore, data is stably written to the second storage layer 213, and the optical disk 201 comes to have a further increased capacity. Now, it will be described how much closer to the outer periphery the periphery of the outer prepit area 208b should be positioned than the recordable area 203b. Assuming that the first storage layer 215 is separated from the second storage layer 213 by a distance of 20 microns, the light beam focused on the second storage layer 213 forms on the first storage layer 215 a spot having a radius of about 10 microns. Therefore, the outer prepit area 208b needs be formed so that its periphery is positioned at least about 10 microns closer to the outer periphery than the periphery of the recordable area 203b. Likewise, the inner prepit area 208a needs be formed so that its periphery is positioned at least about 10 microns closer to the inner periphery than the periphery of the recordable area 203b. Further, if the center of the guiding groove G on the first storage layer 215 does not match the center of the guiding groove G on the second storage layer 213, and hence eccentricity exists, the outer prepit area 208b needs be expanded by an amount equivalent to the eccentricity. In this case, the outer prepit area 208b is preferably formed so that its edges are positioned about 100 microns closer to the outer periphery than the edges of the recordable area 203b. Preferably, the inner prepit area 208a is formed likewise. In this situation, the continuous storage area R may be formed in the pit row in the prepit area 208 either prior to the shipment of the optical disk 201 or by using the optical-disk-read/write apparatus 31 when an unused optical disk 201 is loaded into the optical-disk-read/write apparatus 31. The formation of the continuous storage area R using the optical-disk-read/write apparatus 31 eliminates the need to form the continuous storage area R prior to the shipment of the optical disk 201, and reduces the cost of the optical disk 201. FIG. 59 shows a configuration to form a continuous storage area R in the pit row in the prepit area 208 using the optical-disk-read/write apparatus 31 in the foregoing manner. The configuration includes the aforementioned continuous-storage-area-presence-checking circuit 291 provided in the signal processing and controlling unit 35. The continuous-storage-area-presence-checking circuit 291 as continuous storage area checking means checks and determines based on the reproduction signal produced by the light-receiving element 47 from the reflection off the prepit area 208 whether the prepit area 208 contains a continuous storage area R as mentioned in the foregoing. The continuous-storage-area-presence-checking circuit 291 includes a comparator and other circuits to check and determine whether the pseudo-recording area 207 contains any records, in accordance with whether or not the reproduction signal which represents the quantity of reflected light reflected off the prepit area 208 exceeds a predetermined threshold value. In the arrangement, to check the presence of the continuous storage area R, the prepit area 208 is read immediately after the optical disk 201 is loaded in the optical-disk-read/write apparatus 31. Here, a light beam is projected on the prepit area 208 for tracking under the control of the illuminating-unit-controlling circuit 36 in the signal processing and controlling unit 35. Here, the pit row acts as a tracking guide which is a rough equivalent to the guiding groove G. When there is already formed a continuous storage area R, the quantity of light reflected off the prepit area 208 changes for alternate pit rows, and the reproduction signal representative of the quantity of reflected light varies accordingly. In the continuous-storage-area-presence-checking circuit 291, as mentioned in the foregoing, the varying reproduction signal is converted to a signal of a constant level by a low-pass filter and compared with a predetermined reference value by the comparator. In this case, the signal is larger than the reference value, the continuous-storage-area-presence-checking circuit 291 regards the loaded optical disk 201 as having been used and feeds an ordinary writing-instruction signal to the illuminating-unit-controlling circuit 36. As a result, under the control of the illuminating-unit-controlling circuit 36, ordinary recording takes place on the optical disk 201. Meanwhile, when there is formed no continuous storage area R, the quantity of light reflected off the prepit area 208 does not vary. Neither does the reproduction signal. Therefore, the signal having passed through the low-pass filter is smaller than the reference value, the continuous-storage-area-presence-checking circuit 291 regards the loaded optical disk 201 as being never used, and feeds a continuous-recording-instructing signal to the illuminating-unit-controlling circuit 36 as continuous recording means. As a result, under the control of the illuminating-unit-controlling circuit 36, recording takes place on the optical disk 201 so that a continuous storage area R is formed in the prepit area 208. So far, the description was limited only to the optical disk 201 with only two data storage layers. Instead, the optical disk 201 may include three or more data storage layers. The following will describe such an optical disk 201 with three data storage layers. In addition to a first storage layer 215 and a second storage layer 213, the optical disk 201 includes a third storage layer 218 as a last data storage layer which is most distanced from a light-entering surface, as shown in FIG. 60. The prepit area 206 is provided not in the first storage layer 215 or the second storage layer 213, but only in the third storage layer 218, between a recordable area 203c and a blank area 205c. As to the optical disk 201, similarly to the optical disk 201 shown in FIG. 62, in reading data from a prepit area 206 in the third storage layer 218. the quantity of light reflected off a prepit area 206 varies depending upon whether the first storage layer 215 and the second storage layer 213 through which light beams 217m, 217n pass are fully recorded or not. However, a slice level can be produced from the envelope of a reproduction signal by using the reproduction circuit shown in FIG. 47. Obtaining a digital signal with the slice level as a reference, prepit information can be reproduced stably. In addition, by using the reproduction circuit shown in FIG. 49, prepit information can be reproduced stably by obtaining a digital signal by comparing with a constant slice level a reproduction signal of the prepit area 206 from which low frequency components are removed by a high-pass filter. In this situation, in recording data on the optical disk 201, the recording on the second storage layer 213 is started after the first storage layer 215 is fully recorded, and the recording on the third storage layer 218 is started after the second storage layer 213 is fully recorded. In addition, in focusing a light beam on the second storage layer 213, the light beam needs always be transmitted through a recorded area 203a of the first storage layer 215 so that a light beam of constant intensity reaches the second storage layer 213. To this end, the recordable area 203a is formed wider than the recordable area 203b both on the inner and outer peripheries. Next, as to the optical disk 201 shown in FIG. 61, the third storage layer 218 has the prepit area 206, and the first storage layer 215 and the second storage layer 213 have respective pseudo-recording areas 207a, 207b where pseudo information is recorded. As to the optical disk 201, the pseudo-recording areas 207a, 207b are formed at such positions that the light beams 217m, 217l focused on the prepit area 206 of the third storage layer 218 are always transmitted through the pseudo-recording areas 207a, 207b before reaching the prepit area 206. Using such an optical disk 201, similarly to the optical disk 201 shown in FIG. 50, due to relatively high optical transmittance of the pseudo-recording area 207a, 207b, the intensities of the light beams 217m, 217n passing through the pseudo-recording areas 207a, 207b can be maintained at high values. Therefore, it becomes possible to increase the amplitude of the reproduction signal derived from the prepit area 206 of the third storage layer 218 and eliminate the variations of the reproduction signal along the direction of the circumference. The pseudo-recording areas 207a, 207b may be formed prior to the shipment of the optical disk 201 or using the optical-disk-read/write apparatus 31 in the aforementioned manner. Further, the optical disk 201 shown in FIG. 62 has the prepit area 206 only in the first storage layer 215 which is located close to the light-entering surface. Such an optical disk 201, since the prepit area 206 is located close to the light-entering surface, is free from variations in the quantity of light reflected off the prepit area 206 and its prepit information can be stably reproduced. In addition, to eliminate variations from recording sensitivity, similarly to the case in FIG. 54, in reading or writing in the recordable area 203b of the second storage layer 213, a light beam 217o needs to always pass through a fully recorded recordable area 203a of the first storage layer 215 before reaching the second storage layer 213; and in reading or writing in the third storage layer 218, a light beam 217p needs to always pass through the fully recorded recordable areas 203a, 203b of the first storage layer 215 and the second storage layer 213, respectively, before reaching the third storage layer 218. To this end, the recordable area 203b is formed wider than the recordable area 203c and the recordable area 203a is formed wider than the recordable area 203b. The optical disk 201 shown in FIG. 63 has the prepit area 208 (only the outer prepit area 208b is shown in place of the prepit area 206 in the first storage layer 215 of the optical disk 201 shown in FIG. 62. The optical disk 201, similarly to the optical disk 201 in FIG. 56, has: the prepit area 208 where the optical transmittance is high; the inner prepit area 208a whose inner edge is positioned further inwards than the inner edges of the recordable areas 203b, 203c; and the outer prepit area 208b whose outer edge is positioned further outwards than the outer edges of the recordable areas 203b, 203c. This makes always constant the intensities of a light beam 217r reaching the second storage layer 213 and the light beam 217s reaching the third storage layer 218. Therefore, it data is recorded stably in the second storage layer 213 and the third storage layer 218, and the optical disk 201 is more capacious. As described in the foregoing, an optical read/write apparatus of the present invention causes a read/write light beam from an illuminating section to strike only one side of an optical storage medium including stacked data storage layers each of which is readable/writeable separately from the other layers, and the apparatus includes a controlling section for controlling the illuminating section so that data is read/written from/into a recordable area of a second data storage layer after a recordable area of a first data storage layer is fully recorded, and the first data storage layer is one of the data storage layers which is located closest to a light-striking surface of the medium, and the second data storage layer is another of the data storage layers which is located next to the first data storage layer, opposite the light-striking surface. Further, an optical read/write method of the present invention causes a read/write light beam to strike only one side of an optical storage medium including stacked data storage layers each of which is readable/writeable separately from the other layers, and the method includes the step of reading/writing data from/into a second data storage layer after fully recording a recordable area of a first data storage layers which is located closest to a light-striking surface of the medium, and the second data storage layer is another of the data storage layers which is located next to the first data storage layer, opposite the light-striking surface. According to the arrangement, after fully recording the recordable area of the first data storage layer on the light-striking side, data is read/written from/into the second data storage layer which is located next to the first data storage layer, opposite the light-striking surface. Therefore, when data is read/written from/into the second data storage layer, substantially all the read/write light striking the second data storage layer after passing through the first data storage layer passes through the recordable area of the first data storage layer that has been recorded. Thus, even when an optical transmittance in the recordable area of the first data storage layer varies depending on whether the recordable area holds any record or not, it is possible to illuminate light having uniform intensity to the substantially entire recordable area of the second data storage layer. As a result, it is possible to realize a desirable reading/writing property without using a complex read/write system. An optical read/write apparatus of the present invention causes a read/write light beam from illuminating means to strike only one side of the optical storage medium and is arranged so as to include controlling means for controlling the illuminating means so that an extended area is fully recorded prior to recording in an area other than the extended area in a recordable area in a first data storage layer of the optical storage medium. In addition, an optical read/write method of the present invention is arranged to include the steps of preparing an optical storage medium and fully recording an extended area prior to recording in an area other than the extended area in a recordable area in a first data storage layer of the optical storage medium. According to the arrangement, since an optical storage medium is used which has an extended area in a recordable area of a first data storage layer, as mentioned earlier, light can be projected at uniform intensity on substantially all recordable areas of the second data storage layer. Therefore, desirable read/write characteristics can be imparted without using a complex read/write system. In addition, the area other than the extended area in the recordable area of the first data storage layer is as large as a recordable area in a second data storage layer. The position of the illuminating means relative to the optical storage medium can be controlled in the same manner with respect to read/write in the area other than the extended area in the recordable area of the first data storage layer and with respect to read/write in the recordable area of the second data storage layer. An optical read/write apparatus of the present invention causes a read/write light beam from illuminating means to strike only one side of an optical storage medium and is arranged so as to include: identification information storing means for storing identification information which is unique to the optical read/write apparatus and by which the optical read/write apparatus is distinguished from other optical read/write apparatuses; and controlling means for controlling the illuminating means so that the optical storage medium holds the identification information in an extended area. In addition, an optical read/write method of the present invention is arranged to include the steps of preparing the optical storage medium and storing in an extended area identification information which is unique to an individual optical read/write apparatus capable of reading/writing on the optical storage medium and by which the optical read/write apparatus is distinguished from other optical read/write apparatuses. According to the arrangement, an optical storage medium can store in its extended area identification information by which the optical read/write apparatus having read or written the storage medium can be distinguished. Therefore, if in reading/writing an optical storage medium, for example, the optical read/write apparatus first reads the identification information from the extended area, and only when the identification information readout matches the identification information assigned to the apparatus, is allowed to read or read or write the medium, the illegal copying and other uses of the optical storage medium can be prevented. The optical read/write apparatus may be arranged so that checking means for checking whether the identification information retrieved from the extended area of the optical storage medium matches the identification information of the optical read/write apparatus stored in the identification information storing means, wherein the controlling means controls the illuminating means in reproducing data from the optical storage medium so as to read identification information stored in the extended area of the optical storage medium, and only when the checking means determines that the two sets of identification information match, allows data to be read from the recordable area other than the extended area of any data storage layer. The optical read/write method may be arranged so as to include the steps of, in reproducing data from the optical storage medium, reading the identification information from the extended area of the optical storage medium, checking whether the identification information retrieved from the extended area matches the identification information of the optical read/write apparatus, and only when the two sets of identification information match each other as a result of the checking, starts data to be read from the recordable area other than the extended area of any data storage layer. According to the arrangement, in reading data from the optical storage medium, the optical read/write apparatus first reads the identification information from the extended area of the optical storage medium and only when the identification information readout and the identification information assigned to the apparatus, allows data to be read from the optical storage medium. The illegal copying and other uses of the optical storage medium can be surely prevented. An optical read/write apparatus of the present invention causes a read/write light beam from illuminating means to strike only one side of an optical storage medium and is arranged so as to include: encryption information storing means for storing encryption information by which data is encrypted before being recorded on the optical storage medium; and controlling means for controlling the illuminating means so that the optical storage medium holds the encryption information in the extended area. An optical read/write method of the present invention is arranged to include the steps of: preparing the optical storage medium; preparing encryption information by which data is encrypted before being stored in the optical storage medium; and storing the encryption information in the extended area. According to the arrangement, the extended area of the optical storage medium can hold encryption information by which data is encrypted before being stored in the optical storage medium. Therefore, if when the optical read/write apparatus records information on the optical storage medium, encryption information is read out from the extended area and information is encrypted based on the encryption information before being stored on the optical storage medium, it is only the optical read/write apparatus which can decrypt the encryption information that can decrypt the information read out from the optical storage medium. Therefore, the illegal copying and other uses of the optical storage medium can be prevented. The optical read/write apparatus may be arranged so as to further include encrypting means for encrypting data recorded on the optical storage medium in reference to encryption information in the extended area, wherein the controlling means controls the illuminating means so that recording information encrypted by the encrypting means is stored in the data storage layer. The optical read/write method may be arranged so as to further include the steps of encrypting data to be recorded on the optical storage medium in reference to the encryption information in the extended area and recording the encrypted recording information in the data storage layer. According to the arrangement, based on the encryption information stored in the extended area of the optical storage medium, information to be recorded on the optical storage medium is encrypted before being recorded on the optical storage medium. The optical read/write apparatus may be further arranged so that the controlling means allows reproduction of only the recording information which is encrypted based on the same encryption information as the encryption information stored in the encryption information storing means. The optical read/write method may be further arranged so that only the recording information encrypted based on the same encryption information as the encryption information prepared in advance. According to the arrangement, only the information can be reproduced which is encrypted using the same encryption information as the encryption information assigned to the optical read/write apparatus. Thus, the illegal copying and other uses of the optical storage medium can be prevented if optical read/write apparatuses other than the optical read/write apparatus provided with the encryption information are used. An optical read/write apparatus of the present invention causes a read/write light beam from illuminating means to strike only one side of the optical storage medium and is arranged so as to include controlling means for controlling the illuminating means so as to test write data in the extended area. An optical read/write method of the present invention is arranged to include the steps of preparing the optical storage medium, and test writing data in the extended area. According to the arrangement, the extended area can be utilized as a test write area to determine the most suitable light beam intensity in, for example, writing on the optical storage medium. This eliminates the need to provide a separate test write area in the recordable area other than the extended area of the optical storage medium and allows for more efficient use of the recordable area of the optical storage medium. The optical storage medium may be arranged so that the extended area constitutes a fully prerecorded pseudo-recording area. According to the arrangement, the pseudo-recording area provides the functions of the extended area. Further, the recordable area other than the pseudo-recording area of the first data storage layer is as large as the recordable area of the second data storage layer, and the position of the illuminating means relative to the optical storage medium can be controlled in the same manner with respect to read/write in the recordable area of the first data storage layer and with respect to read/write in the recordable area of the second data storage layer. The optical storage medium may be arranged so that the pseudo-recording area stores identification information which is unique to an individual optical storage medium and by which the optical storage medium is distinguished from other optical storage media. According to the arrangement, in reading or writing data on the optical storage medium using an optical read/write apparatus, the optical storage medium is readable/writeable only with the optical read/write apparatus which matches the identification information. Thus, the illegal copying and other uses of the optical storage medium can be prevented. The optical storage medium may be arranged so that the pseudo-recording area stores encryption information to encrypt information to be stored on the optical storage medium. According to the arrangement, when the optical read/write apparatus records information on the optical storage medium, the optical read/write apparatus first reads the encryption information from the pseudo-recording area, encrypts the information based on the encryption information before the information is stored on the optical storage medium; thus, it is only the optical read/write apparatus that can decrypt the encryption information that can decrypt the information read out from the optical storage medium. Therefore, the illegal copying and other uses of the optical storage medium can be prevented. An optical read/write apparatus of the present invention causes a read/write light beam from illuminating means to strike only one side of the optical storage medium, and is arranged so as to include: encrypting means for encrypt data recorded on the optical storage medium in reference to the encryption information in the pseudo-recording area; and controlling means for controlling the illuminating means so that the recording information encrypted by the encrypting means is recorded in the data storage layer. An optical read/write method of the present invention is arranged to include the steps of preparing the optical storage medium; encrypting data recorded on the optical storage medium in reference to the encryption information in the pseudo-recording area; and recording the encrypted recording information in the data storage layer. According to the arrangement, information can be encrypted based on the encryption information recorded in the pseudo-recording area of the optical storage medium before being recorded on the optical storage medium. The optical storage medium may be arranged so that the pseudo-recording area is not rewriteable. According to the arrangement, the identification information and the encryption information stored in the optical storage medium pseudo-recording area can be protected. The illegal copying and other uses of the optical storage medium is better prevented. In addition, as described earlier, in the present invention, in an arrangement whereby: a lumped address scheme is used, multiple data storage layers are readable/writeable using a light incident to only one side; and the optical transmittance varies due to the recording using incident light, attempts are made to achieve desirable read/write characteristics. To this end, for example, the optical disk 101 includes stacked data storage layers each of which is readable/writeable separately from the other data storage layers and each data storage layer has an address area 104 in which address pits 112 are collectively formed. The second data storage layer of the optical disk 101 is readable/writeable using light transmitted through the first data storage layer. The address area 104 of the first data storage layer has a continuous storage area 114 where the transmittance has varied and a non-recorded area where the transmittance has not varied. Thus, the quantity of light transmitted through the address area 104 is made closer to the quantity of light transmitted through the non-address area 105. An optical storage medium of the present invention includes stacked multiple data storage layer each of which is readable/writeable separately from the other data storage layers by means of only a light beam striking one side of the optical storage medium, each of the data storage layers having address tracks and at least one address area where there are collectively formed address information portions representing address information, the optical storage medium exhibiting an optical transmittance which varies when data is written by means of the incident light, and is arranged so that one of every adjacent two of the address tracks in the address area of a first data storage layer is continuously recorded by means of the incident light, and the other is unrecorded, the first data storage layer being one of the data storage layers which is located closest to a light-striking surface of the optical storage medium, a second data storage layer being another of the data storage layers which is located next to the first data storage layer, opposite the light-striking surface. In addition, an optical read/write apparatus of the present invention causes a read/write light beam from illuminating means to strike only one side of an optical storage medium including multiple stacked data storage layers each of which is readable/writeable separately from the other data storage layers by means of only a light beam striking one side of the optical storage medium, each of the data storage layers having multiple address tracks and at least one address area where there are collectively formed address information portions representing address information, the optical storage medium exhibiting an optical transmittance which varies when data is written by means of the light beam, and is arranged so that the optical read/write apparatus includes controlling means for controlling the illuminating means so that one of every adjacent two of the address tracks in the address area of a first data storage layer is continuously recorded by means of the incident light, and the other one is unrecorded, the first data storage layer being one of the data storage layers which is located closest to a light-striking surface of the medium, a second data storage layer being another of the data storage layers which is located next to the first data storage layer; opposite the light-striking surface. In addition, an optical read/write method of the present invention includes the step of causing a read/write light beam to strike only one side of an optical storage medium including multiple stacked data storage layers each of which is readable/writeable separately from the other data storage layers by means of only a light beam striking one side of the optical storage medium, each of the data storage layers having multiple address tracks and at least one address area where there are collectively formed address information portions representing address information, the optical storage medium exhibiting an optical transmittance which varies when data is written by means of the light beam, and is arranged so as to further include the step of continuously recording one of every adjacent two of the address tracks in the address area of a first data storage layer by means of the incident light, while leaving the other one unrecorded, the first data storage layer being one of the data storage layers which is located closest to a light-striking surface of the medium, a second data storage layer being another of the data storage layers which is located next to the first data storage layer, opposite the light-striking surface. According to the arrangement, one of every adjacent two of the address tracks in the address area of the first data storage layer located close to the light-striking surface of the optical storage medium is continuously recorded by means of the incident light, and the other is unrecorded. Therefore, in reading/writing in the second data storage layer, in a case where the light projected to focus on the second data storage layer forms a light spot on the first data storage layer, the recorded area encompassed in the light spot of a non-address area in the recordable area of the first data storage layer, for example, the sum of the areas of the recording marks, is substantially equal to the sum of the continuously recorded areas encompassed in the light spot in the address area of the first data storage layer. Thus, the intensity of light projected on the second data storage layer after passing through the address area of the first data storage layer of the optical storage medium can be made substantially equal to the intensity of light projected on the second data storage layer after passing through the non-address area in the recordable area of the first data storage layer. As a result, read/write operations on the second data storage layer become more stable and desirable. In addition, if the address area of the first data storage layer of the optical storage medium is continuously recorded using the optical read/write apparatus of the present invention or the optical read/write method in the aforementioned manner, the cost of the optical disk can be reduced by reducing the manufacturing steps of the optical disk. The optical read/write apparatus may be arranged so that the controlling means, after reproducing the address information, controls the illuminating means based on the obtained address information so that one of every adjacent two of the address tracks is continuously recorded and the other one is unrecorded. The optical read/write method may be arranged so that after reproducing the address information, one of every adjacent two of the address tracks is continuously recorded and the other one is unrecorded, based on the obtained address information. According to the arrangement, one of every adjacent two of the address tracks is continuously recorded and the other one is unrecorded, based on the address information derived from the address area. Therefore, the optical storage medium does not require a particular arrangement to determine whether the address track is to be continuously recorded or unrecorded. An optical storage medium of the present invention includes multiple stacked data storage layers each of which is readable/writeable separately from the other data storage layers by means of only a light beam striking one side of the optical storage medium, each of the data storage layers having address tracks and at least one address area where there are collectively formed address information portions representing address information, the optical storage medium exhibiting an optical transmittance which varies when data is written by means of the light beam, and is arranged so that each of the address tracks in the address area of a first data storage layer has a judgement mark to show whether the address track is to be continuously recorded or left unrecorded, the first data storage layer being one of the data storage layers which is located closest to a light-striking surface of the medium, a second data storage layer being another of the data storage layers which is located next to the first data storage layer, opposite the light-striking surface. In addition, an optical read/write apparatus of the present invention causes a read/write light beam from illuminating means to strike only one side of the optical storage medium, and is arranged so as to include controlling means for determining based on information reproduced from the judgement mark whether each of the address tracks in the address area is to be continuously recorded or left unrecorded and controlling the illuminating means according to a result of the determination so that each of the address tracks is to be either continuously recorded or left unrecorded. In addition, an optical read/write method of the present invention includes the step of causing a read/write light beam to strike only one side of the optical storage medium, and is arranged so as to further include the steps of determining based on information reproduced from the judgement mark whether each of the address tracks in the address area is to be continuously recorded or left unrecorded and controlling according to a result of the determination so that each of the address tracks is to be continuously recorded by means of the incident light or left unrecorded. According to the arrangement, each of the address tracks in the address area of the first data storage layer located on the light-striking side of the optical storage medium has a judgement mark showing whether the address track should be continuously recorded or left unrecorded. The optical read/write apparatus in which the optical storage medium is loaded can readily form based on the judgement mark a continuously recorded area in an address area of the first data storage layer of the optical storage medium. In addition, the optical read/write apparatus can immediately determine based on the judgement mark whether to continuously record the address track and therefore quickly complete the process to continuously record the address track in the address area. In addition, the judgement mark is specified to change into the following state, provided that an area in a non-address area is continuously recorded based on an instruction from the judgement mark. That is, the judgement mark is specified so that in reading/writing in the second data storage layer, in a case where the light projected to focus on the second data storage layer forms a light spot on the first data storage layer, the recorded area encompassed in the light spot of a non-address area in the recordable area of the first data storage layer, for example, the sum of the areas of the recording marks, is substantially equal to the sum of the continuously recorded areas encompassed in the light spot in the address area of the first data storage layer. To this end, the judgement mark shows that, for example, one of every adjacent two of the address tracks in, for example, the first data storage layer is continuously recorded and the other one is left unrecorded. As a result, using the optical storage medium of the present invention, read/write operations on the second data storage layer become more stable and desirable. In addition, according to the optical read/write apparatus of the present invention or the optical read/write method, the process of continuously recording the address area of the first data storage layer of the optical storage medium can be implemented after the shipment of the optical storage medium in the aforementioned manner, and the cost of the optical storage medium can be reduced by reducing the manufacturing steps of the optical storage medium. An optical storage medium of the present invention includes multiple stacked data storage layers each of which is readable/writeable on both a land and a groove formed on the data storage layer separately from the other data storage layers by means of only a light beam striking one side of the optical storage medium, each of the data storage layers having multiple address tracks and at least one address area where there are collectively formed address information portions representing address information, the optical storage medium exhibiting an optical transmittance which varies when data is written by means of the light beam, and is arranged so that: among the address tracks in the address area of a first data storage layer, either those address tracks which extend from the land or those address tracks which extend from the groove are continuously recorded by means of the incident light, and the others are unrecorded, the first data storage layer being one of the data storage layers which is located closest to a light-striking surface of the medium, a second data storage layer being another of the data storage layers which is located next to the first data storage layer, opposite the light-striking surface. In addition, an optical read/write apparatus of the present invention causing a read/write light beam from illuminating means to strike only one side of an optical storage medium including multiple stacked data storage layers each of which is readable/writeable on both a land and a groove formed on the data storage layer separately from the other data storage layer by means of a light beam striking one side of the optical storage medium, each of the data storage layers having multiple address tracks and at least one address area where there are collectively formed address information portions representing address information, the optical storage medium exhibiting an optical transmittance which varies when data is written by means of the light beam, and is arranged to include controlling means for controlling the illuminating means so that in the address area of a first data storage layer, either those address tracks which extend from the land or those which extend from the groove are continuously recorded by means of the incident light, and the others are unrecorded, the first data storage layer being one of the data storage layers which is located closest to a light-striking surface of the medium, a second data storage layer being another of the data storage layers which is located next to the first data storage layer, opposite the light-striking surface. In addition, an optical read/write method of the present invention includes the step of causing a read/write light beam to strike only one side of an optical storage medium including multiple stacked data storage layers each of which is readable/writeable on both a land and a groove formed on the data storage layer separately from the other data storage layers by means of only a light beam striking one side of the optical storage medium, each of the data storage layers having multiple address tracks and at least one address area where there are collectively formed address information portions representing address information, the optical storage medium exhibiting an optical transmittance which varies when data is written by means of the light beam, and is arranged so that in the address area of a first data storage layer, either those address tracks which extend from the land or those which extend from the groove are continuously recorded by means of the incident light, and there others are unrecorded, the first data storage layer being one of the data storage layers which is located closest to a light-striking surface of the medium, a second data storage layer being another of the data storage layers which is located next to the first data storage layer, opposite the light-striking surface. According to the arrangement, in the address area of the first data storage layer on the light-striking side, either those address tracks which extend from the land or those which extend from the groove are continuously recorded when data is written by means of incident light, and the others are left unrecorded. Therefore, in reading/writing on the second data storage layer, in a case where the light projected to focus on the second data storage layer forms a light spot on the first data storage layer, the recorded area encompassed in the light spot of a non-address area in the recordable area of the first data storage layer, for example, the sum of the areas of the recording marks, is substantially equal to the sum of the continuously recorded areas encompassed in the light spot in the address area of the first data storage layer. Thus, the intensity of light transmitted through the address area of the first data storage layer before reaching the second data storage layer can be made substantially equal to the intensity of light transmitted through the non-address area in the recordable area of the first data storage layer before reaching the second data storage layer. As a result, read/write operations on the second data storage layer become more stable and desirable. An optical storage medium of the present invention includes multiple stacked data storage layers each of which is readable/writeable on both a land and a groove formed on the data storage layer separately from the other data storage layers by means of only a light beam striking one side of the optical storage medium, each of the data storage layers having multiple address tracks and at least one address area where there are collectively formed address information portions representing address information, the optical storage medium exhibiting an optical transmittance when data is written by means of the light beam, and is arranged so that: in a first data storage layer, the address area has a first address area and a second address area which are adjacent to each other along tracks, the first data storage layer being one of the data storage layers which is located closest to a light-striking surface of the medium a second data storage layer being another of the data storage layers which is located next to the first data storage layer, opposite the light-striking surface; the address information portions in either the first and second address areas are formed in those address tracks which extend from the land, and the address information portions in the other one of the first and second address areas are formed in those address tracks which extend from the groove; and either an area where the address information portions are formed or an area where no address information portions are formed is continuously recorded. In addition, an optical read/write apparatus of the present invention causes a read/write light beam from illuminating means to strike only one side of an optical storage medium including multiple stacked data storage layers each of which is readable/writeable on both a land and a groove formed on the data storage layer separately from the other data storage layers by means of only a light beam striking one side of the optical storage medium, each of the data storage layers having multiple address tracks and at least one address area where there are collectively formed address information portions representing address information, the optical storage medium exhibiting an optical transmittance which varies when data is written by means of the light beam, and is arranged so as to include controlling means for controlling the illuminating means so that: in a first data storage layer, the address area has a first address area and a second address area which are adjacent to each other along tracks, the first data storage layer being one of the data storage layers which is located closest to a light-striking surface of the medium, a second data storage layer being another of the data storage layers which is located next to the first data storage layer, opposite the light-striking surface; and when the address information portions in either one of the first and second address areas are formed in those address tracks which extend from the land, and the address information portions in the other one of the first and second address areas are formed in those address tracks which extend from the groove, either an area where the address information portions are formed or an area where no address information portions are formed is continuously recorded in the first and second address areas. In addition, an optical read/write method of the present invention comprises the step of causing a read/write light beam to strike only one side of an optical storage medium including multiple stacked data storage layers each of which is readable/writeable on both a land and a groove formed on the data storage layer by means of only a light beam striking one side of the optical storage medium, each of data storage layers having multiple address tracks and at least one address area where there are collectively formed address information portions representing address information, the optical storage medium exhibiting an optical transmittance which varies when data is written by means of the light beam, and is arranged so that: in a first data storage layer, the address area has a first address area and a second address area which are adjacent to each other along tracks, the first data storage layer being one of the data storage layers which is located closest to a light-striking surface of the medium, a second data storage layer being another of the data storage layers which is located next to the first data storage layer, opposite the light-striking surface; and the method further comprises the steps of, when the address information portions in either one of the first and second address areas are formed in those address tracks which extend from the land, and the address information portions in the other one of the first and second address areas are formed in those address tracks which extend from the groove, continuously recording either an area where the address information portions are formed or an area where no address information portions are formed in the first and second address areas by means of the incident light. According to the arrangement, the address area of the first data storage layer located on the light-striking side of the optical storage medium is made of a first address area and a second address area which are adjacent to each other along tracks; the address information portions in either one of the first and second address areas are formed in those address tracks which extend from the land, and the address information portions in the other one of the first and second address areas are formed in those address tracks which extend from the groove; and either an area where the address information portions are formed or an area where no address information portions are formed is continuously recorded. Therefore, in reading/writing on the second data storage layer, in a case where the light projected to focus on the second data storage layer forms a light spot on the first data storage layer, the recorded area encompassed in the light spot of a non-address area in the recordable area of the first data storage layer, for example, the sum of the areas of the recording marks, is substantially equal to the sum of the continuously recorded areas encompassed in the light spot in the address area of the first data storage layer. Thus, the intensity of light transmitted through the address area of the first data storage layer before reaching the second data storage layer can be made substantially equal to the intensity of light transmitted through the non-address area in the recordable area of the first data storage layer before reaching the second data storage layer. As a result, read/write operations on the second data storage layer become more stable and desirable. In addition, if the address area of the first data storage layer of the optical storage medium is continuously recorded using the optical read/write apparatus of the present invention or the optical read/write method in the aforementioned manner, the cost of the optical storage medium can be reduced by reducing the manufacturing steps of the optical storage medium. In addition, the present invention enables stable read/write of information on an optical disk with two or more storage layers without being affected by prepit areas. To this end, the optical disk 201 includes a first storage layer 215 and a second storage layer 213, an outer prepit area 206b as a prepit area is provided outside the outer periphery the recordable area 203b of the second storage layer 213. Predetermined information is stored in the outer prepit area 206b in advance using pits. Prepit information is reproduced by transmitting a light beam 217 through a recordable area 203b of the first storage layer 215 where the optical transmittance is high due to recording to the full capacity and then focusing on the outer prepit area 206b. The provision of the outer prepit area 206b on the second storage layer 213 enables data to be read from and write into the second storage layer 213 without being affected by prepit areas. An optical storage medium of the present invention is preferably such that each of the data storage layers except for the last data storage layer has a pseudo-recording area at such a position that allows light to be transmitted to the prepit area, the pseudo-recording area, when fully prerecorded, exhibiting a higher optical transmittance than other areas. In this manner, a pseudo-recording area, when fully prerecorded, exhibiting a higher optical transmittance than other areas is provided at such a position that allows light to be transmitted to the prepit area, the pseudo-recording area; therefore, the light striking the light-striking side storage layer can reach the prepit area after passing through the pseudo-recording area of any data storage layer, but the last data storage layer. Therefore, the intensity of the reproduction signal of the prepit information reproduced from prepit area does not fall. Therefore, the amplitude of the reproduction signal of the prepit information can be made greater. Another optical read/write apparatus of the present invention causes a read/write light beam from illuminating means to strike only one side of the optical storage medium, and is arranged so as to include: low frequency variation removing means for removing low frequency variations from the reproduction signal obtained from the prepit area; and digital converting means for converting the reproduction signal from which the low frequency variations are removed to a digital signal using the constant voltage as a reference. In addition, an optical read/write method of the present invention includes the step of causing a read/write light beam from illuminating means to strike only one side of the optical storage medium, and is arranged so as to further include the steps of removing low frequency variations from the reproduction signal obtained from the prepit area; and converting the reproduction signal from which the low frequency variations are removed to a digital signal using a constant voltage as a reference. According to the apparatus and method, the reproduction signal obtained from reading off the prepit area is rid of low frequency variations by low frequency variation removing means. The reproduction signal, from which low frequency variations are removed, has an envelope whose mean level is substantially constant. Thereafter, the reproduction signal is converted to a digital signal by digital converting means using the constant voltage as a reference. In this manner, the envelope comes to have a substantially constant mean level, in converting a reproduction signal to a digital signal, the constant voltage can be used as a reference. Therefore, the digital conversion can be carried out without being affected by variations in amplitude of the reproduction signal. For example, as mentioned in the foregoing, incident light illuminating a recorded part and a non-recorded part of the first storage layer is focused on the second storage layer, a digital signal can be produced stably from the reproduction signal even if the intensity of the reproduction signal of the prepit information varies with the rotation of the optical storage medium. Therefore, the prepit information of the second storage layer of the optical storage medium can be stably reproduced. An optical read/write apparatus of the present invention causes a read/write light beam from illuminating means to strike only one side of the storage medium having the pseudo-recording area, and is arranged so as to include: recording status checking means for checking whether the pseudo-recording area is fully recorded or not based on a reproduction signal obtained from the pseudo-recording area; and pseudo-recording means for fully recording data in the pseudo-recording area if the pseudo-recording area is not fully recorded. In addition, an optical read/write method of the present invention includes the step of causing a read/write light beam from illuminating means to strike only one side of the storage medium with the pseudo-recording area, and is arranged so as to further include the steps of fully recording the pseudo-recording area so that the pseudo-recording area transmits light therethrough to the prepit area. According to the apparatus and method, the recording status checking means checks whether or not the pseudo-recording area is fully recorded. If the check turns out that the pseudo-recording area is not fully recorded, the pseudo-recording means fully recorded the pseudo-recording area. Thus, the pseudo-recording area of the optical storage medium is formed by the optical read/write apparatus, and there is no need to form a pseudo-recording area on the optical storage medium in advance before shipment. Therefore, the cost of the optical storage medium can be reduced. Another optical storage medium of the present invention includes: one light-striking side storage layer provided as a data storage layer on a light-striking side; and one or more opposite-side storage layers provided as data storage layers opposite the light-striking side from the light-striking side storage layer, and is arranged so that: the light-striking side storage layer has a prepit area which includes preformed pits representative of data: and an optically transparent recordable area of the light-striking side storage layer is formed wider than the optically transparent recordable areas of the opposite-side storage layers. With the arrangement, the recordable areas of the opposite-side storage layers are smaller than the recordable area on the light-striking side. Therefore, in a case where the prepit area is provided adjacent to the recordable area on the light-striking side storage layer, light transmitted through the prepit area does not enter the recordable areas of the opposite-side storage layers. In addition, since light transmitted near the border between the recordable area of the light-striking side storage layer and the prepit area is focused on the recordable areas of the opposite-side storage layers, even if the recordable areas of the opposite-side storage layers are small as mentioned in the foregoing, the light can be transmitted only through the recordable area of the light-striking side storage layer and focused on the recordable areas of the opposite-side storage layers. Therefore, data can be stably read from and written into the last data storage layer without being affected by the prepit area. Another optical storage medium of the present invention includes: one light-striking side storage layer provided as a data storage layer on a light-striking side; and one or more opposite-side storage layers provided as data storage layers opposite the light-striking side from the light-striking side storage layer, and is arranged so that: the light-striking side storage layer has a prepit area which includes preformed pits representative of data; and the prepit area allows transmission of light so that light reaches the opposite-side storage layers, at a transmittance substantially equal to that of a recordable area of the light-striking side storage layer. With the arrangement, since the prepit area allows light to be transmitted at a transmittance substantially equal that as the transmittance of the recordable area of the light-striking side storage layer, the light passing through the recordable area and through the prepit area has substantially the same intensity. Therefore, data can be read from and written to the last data storage layer stably without being affected by the prepit area. The storage medium in which the prepit area is provided in the light-striking side storage layer is preferably such that the recordable areas of the data storage layers except for the last data storage layer which is most distanced from the light-striking side storage layer exhibit, when fully recorded, higher optical transmittances than other areas. With the arrangement, in projecting read/write light to the recordable areas of the data storage layers except for the last data storage layer, the recordable areas come to have higher optical transmittances than other areas upon completion of recording. Therefore, keeping the recordable area fully recorded enables the light passing through the recordable areas to remain sufficiently intense until it reaches a target data storage layer. Therefore, data can be stably read and written on an optical storage medium with multiple storage layers. An optical read/write apparatus causing a read/write light beam from illuminating means to strike only one side of the optical storage medium includes controlling means for controlling the illuminating means so that the recordable area of the light-striking side storage layer is fully recorded before the recordable areas of the opposite-side storage layers which are adjacent to the light-striking side storage layer is read/written. In addition, an optical read/write method including the step of causing a read/write light beam from illuminating means to strike only one side of the optical storage medium includes the steps of fully recording the recordable area of the light-striking side storage layer and subsequently reading or writing in the recordable areas of the opposite-side storage layers which are adjacent to the light-striking side storage layer. In reading or writing on the optical storage medium using such an apparatus or method, the controlling means controls the illuminating means so that the recordable area of the light-striking side storage layer fully recorded before the recordable area of a target opposite-side storage layer is read or written. Therefore, in reading or writing the opposite-side storage layers, the light passing through the light-striking side storage layer remains sufficiently intense until it reaches the opposite-side storage layers. Therefore, data can be stably read and written on the optical storage medium. An optical storage medium having the transparent prepit area is preferably such that the prepit area, under such illumination to fully record the prepit area substantially identically to the recordable area, exhibits a high optical transmittance substantially equal to that of the recordable area. With such an arrangement, the prepit area, when fully recorded under illumination, comes to exhibit a similar optical transmittance to that of the recordable area. Therefore, the light passing through the recordable area and through the prepit area has substantially the same intensity. Therefore, data can be read from and written to the last data storage layer stably. With this optical storage medium, preferably, on a pit row of the pits in the prepit area, there is formed a continuous, fully recorded storage area with neither the pits nor intervening portions between the pits left unrecorded, so that a fully recorded portion occupies a substantially equal area in a part where light is concentrated in the recordable area and in a part where light is concentrated in the prepit area. With the arrangement, light forms a beam spot in both the recordable area and the prepit area as it strikes the recordable area and the prepit area of the light-striking side storage layer. The continuous storage area is formed on the pit row so that the area of the recorded portion in a part where light is concentrated in the beam spot is substantially equal between the recordable area and the prepit area. Therefore, light transmitted through the recordable area and the prepit area has similar intensity. Therefore, data can be stably read from or written into the last data storage layer. An optical read/write apparatus causing a read/write light beam from illuminating means to strike only one side of the optical storage medium of which the prepit area exhibits a high optical transmittance under illumination includes: continuous storage area checking means for checking based on a signal reproduced from the prepit area whether or not the prepit area has a continuous storage area where areas interposed between the pits are continuously and fully recorded as to a pit row of the pits; and continuous recording means for performing such recording that on the pit row in the prepit area where the continuous storage area is not present, there is formed the continuous storage area so that a fully recorded portion occupies a substantially equal area in a part where light is concentrated in the recordable area and in a part where light is concentrated in the prepit area. In addition, an optical read/write method including the step of causing a read/write light beam from illuminating means to strike only one side of the optical storage medium further includes the step of performing such recording that on the pit row in the prepit area where the continuous storage area is not present, there is formed the continuous storage area where areas interposed between the pits are continuously and fully recorded as to a pit row of the pits so that a fully recorded portion occupies a substantially equal area in a part where light is concentrated in the recordable area and in a part where light is concentrated in the prepit area. With the apparatus and method, the continuous storage area checking means checks whether there is a continuous storage area. If the check turns out that there is a continuous storage area, the continuous recording means performs recording to form a continuous storage area. Thus, the formation of a continuous storage area on the optical storage medium using the optical read/write apparatus eliminates the need to form a continuous storage area on the optical storage medium in advance before shipment. Therefore, the cost of the optical storage medium can be reduced. The invention being thus described, it will be obvious that the same way may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.
	abstract	A fuel assembly for a nuclear reactor that employs dissimilar materials for the fuel assembly grid and the control rod guide thimbles. The guide thimbles are secured to the grid employing a through grid cell sleeve that is welded to the grid and spot weld rings that are secured over the sleeve and welded directly to the guide tube through windows in the sleeve.
061887498	abstract	An X-ray examination apparatus (1), including an X-ray source (2) and an X-ray detector (5), is provided with an X-ray filter (6) which is arranged between the X-ray source and the X-ray detector. The X-ray filter (6) includes a plurality of filter elements (7) whose X-ray absorptivity can be adjusted by adjustment of a quantity of X-ray absorbing liquid (14) within the individual filter elements; a first end of individual filter elements communicates with the X-ray absorbing liquid whereas a second end communicates with an X-ray transparent liquid (12). The X-ray filter is preferably provided with a pressure control system for independent control of the liquid pressure in individual row ducts (11) and individual column ducts (13). Individual filter elements are preferably provided with a piston for separating the X-ray absorbing liquid from the X-ray transparent liquid.
	summary
	description	This application is based on and claims priority to U.S. Provisional Application Ser. No. 60/937,101, filed on Jun. 25, 2007, entitled Ion Planting While Growing A III-Nitride Layer, to which a claim of priority is hereby made and the disclosure of which is incorporated by reference. The present invention relates to semiconductor device fabrication and more particularly to III-nitride device fabrication. As referred to herein III-nitride refers to a semiconductor alloy from the InAlGaN system, including, but not limited to GaN, AlGaN, InAlGaN, AlN, InN, InGaN, and the like. Commercial interest in III-nitride devices is rapidly growing. A basic problem in III-nitride device fabrication is the retention of the stoichiometry of the III-nitride body. Specifically, it is well known that at high temperatures (e.g. above 800° C.) nitrogen may escape from the III-nitride body resulting in the decomposition of the III-nitride. Thus, annealing after implantation presents a challenge in the field of III-nitride device fabrication, which is a technical barrier to the well known process of implantation and annealing used to form PN junctions in a semiconductor body. The present invention relates to a process for semiconductor device fabrication, which can address the problem associated with the doping of a III-nitride body. Thus, according to the present invention, a III-nitride body is doped while it is grown to obtain a doped III-nitride body, thereby avoiding the need for a high temperature anneal. According to one embodiment of the present invention, a suitable substrate for the III-nitride body is placed in a reactor chamber for growing the III-nitride body (e.g. GaN body). The reactor chamber is equipped with an implanter for implanting any desired species. For example, Si can be used if an N-type III-nitride body is desired and Mg can be used if a P-type III-nitride body is desired. Thus, according to the present invention, as the III-nitride body is being grown in the reactor chamber it is implanted with the implanter to obtain a doped III-nitride body. Therefore, implanting takes place in an annealing environment rather than a decomposing environment. In a process according to the present invention, the surface of the growing body is at equilibrium with its surrounding. As a result, the surface does not decompose, while it is annealed. While the method of growth is not critical to the practice of the present invention, each growth method may offer unique advantages over the others. Thus, the method of growth can be selected as desired according to its unique advantages. It is known that at least partial vacuum in the reactor chamber may be required for implanting, while to grow a III-nitride body over a substrate a certain amount of gas pressure may be required. Thus, the implanting technique must be coupled with the growth technique. According to one aspect of the present invention one or more stages of differential pumping can be used to obtain the gas pressure that is necessary for implanting and growth. This technique essentially relies on the finite conductance of gas molecules in a low pressure environment. The preferred pressure when MOCVD is used may be in the range 10-100 Torr, and if MBE is used the preferred pressure may be in the range 10−7 to 10−11 Torr. If MBE is used there may be no worries about neutralization which can occur in MOCVD. In a method according to the present invention, low energies are preferred for implanting. Thus, energies less than tens of KeV (e.g. between 100 eV to tens of KeV) may be used with energies in the range of five to ten KeV being most preferred. Also, the implant beam can be as wide as 1/10 micron and not a few nm. Referring to FIG. 1, an apparatus for the practice of a method according to the present invention includes a reactor chamber 10 for receiving a substrate 12 (e.g. silicon substrate, SiC substrate, III-nitride (e.g. GaN) substrate, sapphire substrate or the like), and an implanter chamber 14. Note that reactor chamber 10 may house also a rotating platform 16 on which substrate 12 is placed, and includes an intake port 18 to allow for the entry of a reactant gas and an output port 20 for the exit of reactant gas. Disposed within implanter chamber 14 is an ion implanter 22 in communication with reactor chamber 10 through an ion path 24, which is the path along which ions travel from the implanter 22 into reactor chamber 10. According to an aspect of the present invention, implanter chamber 14 is configured for maintaining a near vacuum condition within the enclosed space thereof. Near vacuum condition as referred to herein means a vacuum condition necessary to allow passage of ions through the enclosed space of implanter chamber 14 into reactor chamber 10. In order to obtain such a near vacuum condition while allowing implanter chamber 14 to be in communication with reactor chamber 10, differential pumping may be used to evacuate implanter chamber 14. For one embodiment, for example, implanter chamber 14 may be divided into several subchambers 14′, 14″, 14′″. Each subchamber 14′, 14″, 14′″ is in communication with an adjacent subchamber through a respective portal 26. Note that ion path 24 passes through each portal 26, and subchamber 14′″, which is adjacent reactor chamber 10, is linked to reactor chamber 10 through a linking portal 28 through which ion path 24 also passes. To create the near vacuum condition each subchamber 14′, 14″, 14′″ is preferably evacuated using a respective pump 30. Each pump 30 is preferably in direct communication with the space enclosed by a respective subchamber as illustrated schematically by FIG. 1. An apparatus according to the present invention may further include a Faraday cup 32 which may be disposed on platform 16 near substrate 12. Faraday cup 32 is preferably linked to a voltage meter or the like through appropriate means such as wires 34 so that the variation in the voltage thereof can be used to measure the dosage of ions being received from implanter 32 by substrate 12. An apparatus according to the present invention may further include a plurality of deflection plates 36 positioned inside reactor chamber 10 on either side of portal 28. Deflection plates 36 can be used to change the direction of travel of the ions entering reactor chamber 10. Note that deflection plates 36 may be used to direct the ions at Faraday cup 32 periodically (e.g. 1% of the time) in order to measure the ion dosage being directed at substrate 12 in order to estimate the concentration of dopants implanted therein. According to an embodiment of the present invention, a suitable substrate 12 (e.g. a silicon substrate) is placed on platform 16 inside reactor chamber 10. Reactant gas is then fed through intake port 18, and thermal conditions are set for the growth of a III-nitride body such as GaN, AlN, or the like. In addition, through differential pumping, subchambers 14′, 14″, 14′″ are evacuated until a suitable, near vacuum condition is obtained inside implanter chamber 14. The near vacuum condition may depend on the type of growth that is being practiced. For example, if III-nitride is being grown using MOCVD the pressure inside of implanter chamber 14 may be in the range of 10-100 Torr, or if MBE is used for growing the III-nitride body 10−7 to 101−11 Torr may be the pressure inside implanter chamber 14. Once proper pressure is established in implanter chamber 14, any desired species may be implanted into the III-nitride body as it is being grown layer by layer. Thus, N-type dopants such as Si and P-type dopants such as Mg may be implanted. According to one aspect of the present invention, to implant dopants, energies less than tens of keV (e.g. between 100 eV to tens of keV) are used for implantation. Preferably, energies in the range of five to ten keV are used during the implantation. Moreover, the implant beam can be as wide as 1/10 microns wide not just a few nm. Note that according to an aspect of the present invention. The low energies are used in order to implant the dopants near the surface during the growth process (e.g. 50-200 Å depth) into the grown III-nitride body. The III-nitride body can be doped to any concentration, for example, the III-nitride semiconductor body can be doped with an ion dose in the range of 1012/cm2 up to 1016/cm2, with a dose of 1014 to 1015 being preferred. According to another aspect of the present invention, the dosage of implants is measured to determine the concentration of dopants in the III-nitride body as it grows. For example, to calculate the dose the number of electrons emitted can be counted. This technique may be most suitable for MBE. In an alternative technique, the ion beam can be sampled 1% of the time by using a Faraday cup 32 residing on or near the substrate. Deflection plates can be used in the measurement of ion implantation. Faraday cup 32 on the wafer can be used to sample the charge that is implanted. However, negative ions may escape after implantation. To alleviate this problem a negative cover may repel the negative charge to get a better reading. Note that deflection plates (if used) should be positioned after the differential pumps. A process according to the present invention can be used to dope the entire III-nitride body that is being grown on the substrate or it can be used to dope selected regions in the III-nitride body. Thus, to dope selected regions a metal mask can be used to allow doping only of regions not covered by the mask. For example, a projection ion beam mask or a stencil with parallel ion beams can used. Alternatively, a direct writing rastering technique may be used. To directly write, a highly focused beam can used to implant selected regions without using a mask. Although the present invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. It is preferred, therefore, that the present invention be limited not by the specific disclosure herein, but only by the appended claims.
	description	The present teachings relate to systems and methods for the storage and processing of radioisotopes. The statements in this section merely provide background information related to the present disclosure and may not constitute prior art. Large-scale production of radioisotopes is now possible, necessitating safe storage of large quantities of the irradiated materials. Generally, the radioisotopes comprise pellets, wires, disks, etc., of a desired isotopic material, e.g., cobalt, that has been irradiated to have a desired radioactivity. In many instances, these radioisotopes will be used to construct, or assemble, many different customer specified source capsules having many different desired activity profiles, i.e., many different containers having one or more radioisotopes sealed therein to provide various desired activity profiles. The operations required for such encapsulation must be done in a shielded facility and require large amounts of repetitive work to be performed. Traditionally, an inventory of various isotopes is stored in a plurality of storage structures. Particularly, rods or tubes in which the radioisotopes are produced are stored in a plurality of radioactive shielded storage structures. To assemble, or construct, a source capsule having a particular customer requested activity profile, radioisotopes of various radioactivity, from various storage structures, are placed in radioactive shielded casks, removed from the respective storage structures. The casks are then transported to a separate assembly facility, commonly referred to as a ‘hot cell’. Once the various radioisotopes have been transported to the hot cell, the casks will be opened to access the respective radioisotopes. The desired amount of each respective radioisotope will be then removed and sealed in a capsule, e.g., a stainless steel container, to provide a source capsule having the desired activity profile. The unused radioisotopes will then be returned to the casks. The casks will then be removed from the hot cell and transported back to the respective storage structures. Thus, the process of loading the various radioisotopes stored in the various storage structures in casks, transporting the casks to the hot cell, opening the casks to access the radioisotopes, assembling the source capsules, repacking the casks and returning the casks to the storage structures is a cumbersome and time consuming task. In various embodiments, a system for storing radioactive material is provided, wherein the system includes a storage pool for storing a plurality of radioactive objects submersed in a radiation shielding and cooling liquid. The system additionally includes an assembly building located above the storage pool for constructing one or more radioactive article using the radioactive objects transferred from the storage pool. Furthermore, the system includes at least one transfer shaft connecting the storage pool and the assembly building. The transfer shaft(s) is/are used for transferring the radioactive objects directly from within the storage pool to an interior of the assembly building and directly from the interior of the assembly building into the storage pool. In various other embodiments, a system for storing radioactive material is provided, wherein the system includes a storage pool disposed within and beneath a floor of the system. The storage pool is structured for storing a plurality of radioisotopes submersed in a radiation shielding and cooling liquid. The system additionally includes a capsule assembly building disposed on the system floor above the storage pool. The capsule assembly building can include an assembly chamber comprising a plurality of interior cells for constructing one or more radioactive capsules using radioisotopes transferred from the storage pool to the capsule assembly building. The system further includes at least one transfer shaft connecting the storage pool and the capsule assembly building to provide direct access to the storage pool from an interior of the capsule assembly building. Therefore, the transfer shaft(s) provide for transferring the radioisotopes from within the storage pool directly to the interior of the capsule assembly building and from the interior of the capsule assembly building directly into the storage pool. In still other embodiments, a method for storing radioactive material is provided, wherein the method includes storing a plurality of radioisotopes submersed in a radiation shielding and cooling liquid within a storage pool, and transferring selected radioisotopes directly from within the storage pool to an interior of an assembly chamber of an assembly building. The assembly building can be located above the storage pool. The selected radioisotopes are transferred from within the storage pool directly to the interior of an assembly chamber via at least one transfer shaft connecting the storage pool and the assembly building. The method additionally includes constructing one or more radioactive capsules within the assembly chamber using the radioisotopes transferred from the storage pool. The method further includes transferring the selected radioisotopes not used to construct the one or more radioactive capsules directly from the interior of the assembly chamber into the storage pool using the at least one transfer shaft. Further areas of applicability of the present teachings will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present teachings. The following description is merely exemplary in nature and is in no way intended to limit the present teachings, application, or uses. Throughout this specification, like reference numerals will be used to refer to like elements. FIGS. 1 and 2 illustrate a facility 10 structured and operable to provide safe storage of radioactive materials, such as radioisotopes, and also provide quick, convenient and safe access to the stored radioactive material for processing of the radioactive material into various useful items and/or products. For example, in various embodiments, the facility 10 includes a storage pool 14 connected to an assembly building 18 via at least one radioactive material transfer shaft 22. Although the facility 10 can include one or more transfer shafts 22 connecting the storage pool 14 with the assembly building 18, for consistency and simplicity, the facility 10 will be described herein to include a pair of redundant transfer shafts 22. The storage pool 14 is structured to be filled with a radiation shielding and cooling liquid, e.g., water, such that a plurality of radioactive objects 26 and/or a plurality of radioactive articles 28 constructed from the radioactive objects 26 can be submerged and stored therein. The radioactive articles 28 and/or radioactive objects 26 can comprise any radioactive material such as Cobalt 60 (Co-60), iridium, nickel, etc. In various embodiments, the radiation shielding and cooling liquid can be circulated through a chiller (not shown) to cool the liquid in order to provide a desired cooling for the stored radioactive objects 26 and/or articles 28. The cooling liquid captures decay heat emanated from the radioactive objects 26 and/or radioactive articles 28 submerged within the storage pool 14. The amount of heat needing to be dissipated is dependent on the curie content of the storage pool 14 and the specific radioactive objects 26 and/or radioactive articles 28 being stored. As an example, if the storage pool 14 were near its capacity for storage of Cobalt 60 (Co-60) radioactive objects 26 and/or radioactive articles 28, generating 0.015 Wafts/Ci, then the cooling liquid (optionally circulated through a chiller) can be utilized to maintain radioactive objects 26 and/or radioactive articles 28 at approximately 100° F. In alternative implementations the cooling liquid (optionally circulated through a chiller) can be utilized to maintain radioactive objects 26 and/or radioactive articles 28 at approximately 100° F. to 200° F. Additionally, it is envisioned that the storage pool 14 can be sized to hold a very large quantity, e.g., thousands, of the radioactive objects 26 and/or articles 28. The assembly building 18 is constructed to be a radiation shielding and containment structure suitable for safely housing radioactive objects 26 and/or articles 28 transferred directly from the storage pool 14 to an interior of the assembly building 18, via the transfer shafts 22. As described further below, in operation, to construct the radioactive article(s) 28, radioactive objects 26 are selected from within the storage pool 14 and transferred directly to an interior of the assembly building 18 where the radioactive objects 26 are used to construct one or more radioactive articles 28 for a particular use. For example, in various embodiments, the radioactive objects 26 can comprise radioactive rods 32 containing various radioisotopes having various radioactive intensities and the radioactive articles 28 can comprise source capsules 34 that have been constructed within the assembly building 18 to have desired activity profiles and returned to the storage pools 14 for safe storage. Particularly, a large number of radioactive rods 32 and/or source capsules 34 can be stored in a plurality of racks 40 within the storage pool 14. To assemble, or construct, the source capsules 34, one or more rods 32 containing particular radioisotopes can be transferred directly from the storage pool 14 to the interior of a radioactive containing assembly chamber 42 of the assembly building 18, via the transfer shafts 22. Once the rods 32 have been transferred into the assembly chamber 42, the rods 32 can be opened to access the respective radioisotopes. The radioisotopes can then be used to construct one or more radioactive source capsules 34 having desired activity profiles. The source capsules 34 can then either be returned to the storage pool 14 for storage or transported to a desired location, e.g., a medical facility for use in medical imaging and/or treatment. In such embodiments, the assembly can also be referred to as the capsule assembly chamber 42. In various embodiments, the assembly building 18 is located above, or higher, and in close proximity to, the storage pool 14 such that the radioactive objects 26 and/or articles have a relatively short distance to travel through the transfer shafts 22 when being transferred between storage pool 14 and the assembly building 18. For example, in various embodiments, as illustrated in FIGS. 1 and 2, the storage pool 14 can be disposed within and beneath a floor 30 of the facility 10 and the assembly building 18 can be disposed on the facility floor 30 above and in close proximity to the storage pool 14. Accordingly, the transfer shafts 22 are disposed within and beneath the floor 30 and extend between a bottom portion of a side wall 36 of the storage pool 14 and a floor 38 of the assembly chamber 42. Alternatively, in various other embodiments, the storage pool 14 can be disposed within and partially beneath the floor 30 or built to stand on or above the floor 30. In such embodiments, the assembly building 18 would be supported above the floor 30 and above the top of the storage pool 14, having the transfer shafts 22 extending there between. Additionally, in various embodiments, as illustrated in FIG. 3, the assembly chamber 42 can include an annex 44 extending from the assembly chamber 42 toward the storage pool 14. Particularly, the annex 44 is located substantially above, or over, the storage pool side wall 36 such that the transfer shafts 22 have a substantially vertical orientation between the storage pool 14 and the annex 44. Referring to FIGS. 1 and 4, in various embodiments, the assembly facility 18 generally includes the assembly chamber 42 and at least one interlock 46 connected to at least one of opposing ends 50 of the assembly chamber 42. The assembly chamber 42 includes opposing radiation shielding and containment side walls 54 that each joins a radiation shielding and containment ceiling 58. The radiation shielding and containment side walls 54 and ceiling 58 provide a radiation containment environment within the interior of the assembly chamber 42 that contains radioactive radiation from the objects 26 and/or articles 28 transferred from the storage pool 14 within the assembly chamber 42. As shown in FIG. 4, each interlock 46 includes a radiation shielding and containment interlock door 62 operable to provide radiation containment within the interior of the assembly chamber 42 when in a ‘Closed’ position. When in an ‘Opened’ position, each radiation shielding and containment interlock door 62 allows ingress and egress to and from the interior of the assembly chamber 42 for removal of the assembled radioactive articles, e.g., radioactive source capsules 34. Each interlock 46 additionally includes at least one exterior access door 66 operable to allow access to an interior of the respective interlock 46 for disposition and/or removal of items, such as casks for transporting the assembled radioactive articles 28 from the assembly chamber 42. Referring now to FIGS. 4 and 5, in various embodiments, the assembly chamber 42 is structured to include a plurality of radioactive shielding partitions 70 within the interior of the assembly chamber 42. The radioactive shielding partitions 70 form a plurality of interior assembly cells, or stations, 74 used for assembling, or constructing, the radioactive articles, e.g., radioactive source capsules 34. In various embodiments, a height h of each radioactive shielding partition 70 is only a portion of a height H of the assembly chamber interior. Additionally, it is envisioned that in various implementations, the radioactive shielding partitions 70 can be moveable, i.e., able to be relocated, within the assembly chamber 42 to form various size assembly cells 74. Additionally, the assembly chamber 42 can include an overhead crane device 78 structured and operable to be controllably movable from one end 50 of the assembly chamber 42 to the opposing end 50 along tandem tracks, or cables, 82 that extend from one end 50 of the assembly chamber 42 to the opposing end 50, e.g., extend between opposing interlocks 46. More particularly, the overhead crane device 78 includes a winch 80 that is controllably translatable along a length L of a frame 81 of the crane device 78. Thus, the crane device 78 is structured and operable to move radioactive objects 26 and assembled articles 28 over the radioactive shielding partitions 70 and between any of the various assembly cells 74, between any of the various assembly cells 74 and any of the interlocks 46, and between opposing interlocks 46. Referring to FIGS. 4, 5 and 6, in various other embodiments, in addition to the overhead crane device 78, the assembly chamber 42 can include an under-floor conveyor belt system 84 located within and/or beneath the floor 38 of the assembly chamber 42. The under-floor conveyor belt system 84 can be constructed of any material suitably designed to be corrosion resistant. For example, in various embodiments, the under-floor conveyor belt system 84 can be constructed of stainless steel or similar materials. To provide access to the under-floor conveyor belt system 84, the assembly chamber floor 38 includes an opening 86 that extends longitudinally along the floor 38 under the assembly cells 74. The conveyor belt system 84 is located below the opening 86 and is structured and operable to controllably move the radioactive objects 26 and articles 28 between the various assembly cells 74 beneath the radioactive shielding partitions 70. Referring again to FIGS. 4 and 5, in various embodiments, the assembly chamber 42 can include one or more movable divider panels 90 structured and functional to connect to, or mate with, the top of any of the radioactive shielding partitions 70. When connected to, or mated with, one of the radioactive shielding partitions 70, the respective movable divider panel 90 and radioactive shielding partition 70 forms a full length wall extending substantially from the floor 38 to the ceiling 58 and from the wall 54 to the wall 54 of the assembly chamber 42. In various embodiments, the divider panels 90 can be slideably supported by and suspended from the crane device tracks 82. Thus, the divider panels 90 can be moved along, i.e., slid along, the tracks 82 to position the respective divider panel 90 in contact with a top of a respective radioactive shielding partition 70. Subsequently, the respective divider panel 90 can be coupled with the respective radioactive shielding partition 70 via any suitable mating and/or connecting means. For example, the divider panels 90 radioactive shielding partitions 70 can be structured to mate in a ‘tongue and groove’ manner or by any other interlocking mating manner. Or, the respective divider panel 90 can be coupled with the respective radioactive shielding partition 70 using any suitable fastening means, such as nuts and bolts, locking pins, or any other suitable latching means. In various implementations, the assembly cells 74 include at least one docking cell 74A, e.g., the centermost assembly cell 74, and at least one other assembly cell 74 for constructing the one or more radioactive articles therein. A disposition end 92 of each transfer shaft 22 (shown in FIG. 2) is connected to a respective aperture 94 in the floor 38 of the assembly chamber docking cell 74A. The docking cell apertures 94 provide an inlet to, and outlet from, the assembly chamber 42 for the radioactive objects 26 and/or articles 28 transferred directly to and from the storage pool 14. Similarly, a storage end 98 of each transfer shaft (shown in FIG. 2) is connected to a respective aperture 102 in the storage pool side wall 36 (shown in FIG. 1). The storage pool apertures 102 provide an inlet to, and outlet from, the storage pool 14 for the radioactive objects 26 and/or articles 28 transferred directly to and from the assembly chamber docking cell 74A. Thus, the radioactive objects 26 and/or articles 28 can be transferred directly from the storage pool 14 to the docking cell 74A, via the transfer shafts 22, the docking cell apertures 94 and the storage pool apertures 102. Referring now to FIGS. 3 and 7, in various embodiments, each transfer shaft 22 includes an elevator system 106 structured and operable to transfer the radioactive objects 26 and/or articles 28, e.g., radioisotope rods 32 and/or radioactive source capsules 34, directly from the storage pool 14 to the interior of the assembly chamber 42 through the respective transfer shaft 22. In various implementations, the elevator system 106 is additionally structured and operable to transfer the radioactive objects 26 and/or articles 28, e.g., radioisotope rods 32 and/or radioactive source capsules 34, directly from the interior of the assembly chamber 42 to storage pool 14 through the respective transfer shaft 22. The elevator system 106 includes at least one tray 110 coupled to a conveyor 114 structured and operable to move the tray(s) 110 within the respective transfer shaft 22 directly between the storage pool 14 and the interior of the assembly chamber 42. The elevator system 106, including tray(s) 110 and a conveyor 114, can be constructed of any material suitably designed to be corrosion resistant. For example, in various embodiments, the elevator system 106, including tray(s) 110 and a conveyor 114, can be constructed of stainless steel or similar materials. The conveyor 114 can be any system, device or mechanism suitable for conveying, i.e., transferring, moving or translating, the elevator system tray(s) 110, and any radioactive object 26 and/or article 28 placed thereon, along the interior length of the respective transfer shaft 22. For example, the conveyor 114 can be a conveyor-belt type system, a chain-and-sprocket type system, a cable-and-pulley type system, a threaded shaft type system, any combination thereof, or any other suitable conveying system. Referring now to FIGS. 1, 5, 6 and 8, in various embodiments, the assembly chamber 42 includes a plurality of manipulator ports 118 spaced along and extending through each of the assembly chamber side walls 54. The assembly chamber 42 additionally includes a plurality of object manipulators 122 that are spaced along each assembly chamber side wall 54 and extend through each of the manipulator ports 118. The object manipulators 122 may be robotic arms configured to articulate in designed fashion to construct a radioactive article 28. To this end, respective robotic arms may be with a tool such as a grasping claw, welder, screwdrivers, etc. for constructing radioactive article 28. As will be appreciated, the object manipulators 122 are controllable by facility personnel, e.g., operators 126 (FIG. 8), from the exterior, i.e., outside, of the assembly chamber 42. More specifically, the operators 126 operate controls (not shown) included at a proximal end 130 of each object manipulator 122 that protrudes, or extends, externally from the respective assembly chamber side wall 54. Operation of the controls by the operators 126 controls movement and operation of a distal end 134 of each respective object manipulator 122 that protrudes, or extends, into the interior of the assembly chamber 42. Particularly, the distal end 134 of each object manipulator 122 extends into a respective assembly cell 74/74A to manipulate radioactive objects 26 and/or articles 28 within the assembly cells 74/74A. Accordingly, to move the radioactive objects 26, e.g., radioisotope rods 32, between and within the assembly cells 74/74A and to assemble/construct the radioactive articles 28, e.g., radioactive source capsules 34, an operator 126 controls the movement and actions of the object manipulator distal ends 134 inside the assembly chamber 42 by manipulating the controls at the object manipulator proximal ends 130. In various embodiments, the assembly chamber 42 includes one or more object manipulators 122 for each assembly cell 74/74A. Accordingly, a plurality of radioactive articles 28, e.g., radioactive source capsules 34, can be assembled substantially simultaneously utilizing the plurality of assembly cells 74/74A and the respective corresponding object manipulators 122 In operation, to assemble, or construct, one or more radioactive articles 28, one or more of the plurality of radioactive objects 26, e.g., radioisotope rods 32, stored in the storage pool 14 is/are selected, removed from the respective one of the plurality of racks 40, and moved to one of the storage pool side wall apertures 102. The radioactive object(s) 26 is/are selected based on particular desired characteristics of the particular object(s) 26, i.e., size, material, isotope, radioactivity, etc. Once the selected radioactive object(s) 26 have been moved to the storage pool side wall apertures 102, the radioactive object(s) 26 is/are placed on the elevator system tray 110 for transfer directly to the assembly chamber interior docking cell 74A. Any suitable means can be employed to remove the selected radioactive object(s) 26 from the respective rack(s) 40, move the selected radioactive object(s) 26 to one of the storage pool side wall apertures 102 and place the selected radioactive object(s) 26 on the elevator system tray 110. For example, robotic devices, mechanisms, assemblies or systems (not shown) can be utilized to select the radioactive object(s) 26, move them to one of the storage pool side wall apertures 102 and place them on the elevator system tray 110. Or, alternatively, long mechanical grasping poles can be disposed into the storage pool and hand manipulated by facility personnel from the facility floor 30 to select the radioactive object(s) 26, move them to one of the storage pool side wall apertures 102 and place them on the elevator system tray 110. After the selected radioactive object(s) 26 have been placed on the elevator system tray 110, the elevator system conveyor 114 is operated to transfer the selected radioactive object(s) 26 directly from the storage pool 14, through the respective transfer shaft 22 directly into the interior of the assembly chamber 42, i.e., directly into the docking cell 74A. The object manipulators 122 and/or the overhead crane device 78 and/or the under-floor conveyor system 84 can then be operated to manipulate the transferred radioactive object(s) 26 and move them from the docking cell 74A to one or more of the various other assembly cells 74. Once the radioactive object(s) 26 have been delivered to the one or more assembly cells 74, the facility personnel can operate the object manipulators 122 to assemble/construct, the radioactive articles, e.g., radioactive source capsules 34. The object manipulators 122 can also be utilized to place or package the assembled/constructed radioactive articles in shielded containers or casks. The overhead crane device 78 can then be operated to move the packaged radioactive articles into one of the interlocks 46 from which the packaged radioactive articles can be safely removed for delivery to a selected location. Subsequently, the object manipulators 122 and/or the overhead crane device 78 and/or the under-floor conveyor system 84 can then be operated to manipulate the unused radioactive object(s) 26 and move them from the one or more assembly cells 74 to the docking cell 74A for return to the storage pool 14. The unused radioactive object(s) 26 can then be placed into one of the docking cell floor apertures 94 and onto a respective elevator system tray 110. The elevator system conveyor 114 is then operated to transfer the unused radioactive object(s) 26 directly from the interior of the assembly chamber 42, i.e., directly from the docking cell 74A, through the respective transfer shaft 22 and directly to the respective storage pool side wall aperture 102. The returned unused radioactive object(s) 26 can then be returned to the proper rack 40 submersed within the shielding and cooling liquid of the storage pool 14. Referring now to FIG. 9, in various embodiments, the facility 10 can include two or more assembly buildings 18 coupled to a single storage pool 14 via respective corresponding transfer shafts 22. Accordingly, two or more assembly buildings 18 can have direct access to the single storage pool 14. More particularly, selected radioactive objects 26, e.g., the radioactive rods 34, stored within the storage pool can be simultaneously or concurrently transferred directly to any of the assembly buildings 18, via the respective corresponding transfer shafts 22, to simultaneously or concurrently assemble a plurality of radioactive articles 28, e.g., radioactive source capsules 34, as described above. It should be understood that spatially relative terms, such as “beneath”, “below”, “lower”, “above”, “upper” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the example term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly. The description herein is merely exemplary in nature and, thus, variations that do not depart from the gist of that which is described are intended to be within the scope of the teachings. Such variations are not to be regarded as a departure from the spirit and scope of the teachings.
055090397	abstract	A pellet stack length recording switch, for use in a measurement system having a movable measuring head and a measuring device for measuring a length of a nuclear fuel pellet stack segment, includes a probe for contacting and applying a compression force to an end of the pellet stack segment, a compression spring having a predetermined compression force and cooperating with the measuring head and the probe, a pin mechanism attached to the probe, and a sensor for sensing a position of the pin mechanism and outputting a position signal for triggering a measurement by the measuring device of the length of the pellet stack segment when the compression force applied by the probe is at least equal to the predetermined compression force. The probe may include a slider block, for compressing the spring, and a probe member attached to the slider block. The pin mechanism may include a trip screw for tripping the sensor. The slider block may have a bore running therethrough for positioning the pin mechanism and the spring therein, and the measuring head may have a leg and a bore running therethrough for positioning a shaft of the pin mechanism therein. The sensor may be a Fiber optic sensor having a light beam which is broken by the pin mechanism. The switch may further include a foot switch cooperating with the sensor for triggering a measurement by the measuring device whenever the foot switch is closed and the light beam of the fiber optic sensor is broken.
050142917	summary	BACKGROUND AND SUMMARY OF THE INVENTION This invention refers to a method for X-ray amplification and to an applicance for putting into practice of same. The purpose of the invention is a method for amplification of X-ray intensity, and also a device for practicing the same method, that by using the physical characteristics of the X-rays themselves, can lead to the realization of an appliance which is efficient and reliable, not costly, which does not require much space and is of relatively simple construction. The invention solves this problem by taking the primary X-rays obtained from a convention X-ray tube and reflecting them repeatedly onto an electrode, made of suitable metallic material, and maintained at a certain potential and in certain conditions of excitation that allow the incident rays not only to reflect themselves, but also induction of X-ray emission from the reflective material. Part of the rays generated in this manner join the reflected primary rays amplifying the intensity. To be able to considerably reinforce the intensity of the incidental radiation, the reflection-emission operation must be repeated several times in succession. To put this method into practice, the invention provides for an amplifying device consisting of two concentric metal rings, of metallic material suitable for the purpose, between which a suitable exciting gas, such as Xexon, is introduced and to which are applied a measure of potential difference that induces acceleration of the particles of the exciting gas so that they hit the surfaces of the metal rings, bringing them into a state of excitation favourable to the emission of X-rays. Concerning the invention it is appropriate to place the said amplifying device inside a container that can be made vacuum, made for example of glass. The device may also be made to function without the emission of gas, by applying an appropriate electrical potential between the two electrodes. Furthermore, the device is provided with entrance and exit channels positioned substantially tangent to the inside metallic ring, at such an angle, that the incidental X-rays through the entrance channel leave by the exit channel after several reflections. The invention has other characteristics which further improve the above mentioned device.
	description	The simple X-ray imaging system 10 depicted in FIG. 1 includes a collimated white beam generator 11. The generator is preferably but not exclusively a synchrotron radiation generator. Further components are a defining slit 12, a filter 13, a detector 14 and a computer 15. A defining slit 12 is positioned behind of the collimated white beam generator 11 in order to travel the collimated white beam 1 through the defining slit 12. The filter 13 is situated behind the defining slit 12. An object O is situated behind the filter 13. If necessary, an object stage may be arranged behind the slit 12 so as to hold the object O to detect in a position. The detector 14 is situated behind the object O in order to detect the beam passing through the object. The detector 14 includes a CdWO4 single crystal scintillator 14a cleaved to a thickness of less than 100 xe2x96xa1mxe2x80x94which is resistant to radiation damage and highly homogenous, an optical microscopy objective 14b with either 10xc3x97 or 32xc3x97 and a commercial-grade CCD video camera 14c. The high-resolution radiograph on the scintillator is magnified with an optical microscopy objective with either 10xc3x97 or 32xc3x97magnification, and captured by a commercial-grade CCD video camera. The detector provided a good compromise between lateral resolution and high intensity (required for time resolution). It enables us to see details with a resolution of 2-3 xe2x96xa1m, and to detect their evolution in real time, with a video rate of 30 image frames/sec. In an other embodiment, the detector also may include a X-ray CCD camera. In particular, in the embodiments electronic imaging detectors such as those based on charge coupled devices (CCD""s) may be used for high speed and, in some cases, real-time recording of images. A computer 15 is connected to the detector 14 in order to obtain an image of the object based on the output of the detector 14. Now, a method of imaging an object will be described below. A collimated white beam is generated by a source 11. The collimated white beam 1 is usually emitted from a synchrotron radiation source. In this embodiment, from the DB-beamline at the SRRC (Synchrotron Radiation Research Center, Hsinchu, Taiwan) 1.5 GeV storage ring and on the 1B2 beamline at PLS (Pohang Light source, Pohang, Korea), operating at 2.5 GeV is emitted a collimated white beam 1. The collimated white beam 1 is then introduced into a slit 12. The beam 1 travelling through the slit 12 is introduced into a filter 13. The filter 13 filters out photon energies lower than a selected energy level from the collimated white beam introduced into the filter 13, thereby producing an unmonochromatized beam 2. In this embodiment, the selected energy level of the collimated white beam is about 10 KeV. The collimated white beam filtered out by the filter 13, that is xe2x80x9can unmonochromatized beamxe2x80x9d is irradiated into an object O. Since longitudinal coherence is not a stringent requirement for refractive-index radiology, in this embodiment an unmonochromatized beam without any special optical element is used. At this time, the object O is placed on a beam path. The term xe2x80x9cunmonochromatized beamxe2x80x9d is defined herein as X-rays with a broad-band width photon energy distribution in which photon energies lower than a selected photon energy level are filtered out from a collimated white beam by a filter. Unmonochromatized beam image 3 having passed through the object O is detected by a detector 14, thereby providing an image. A scintillation crystal 14a included in the detector 14 serves to convert X-rays into visible rays. Image of the object O based on the output of the detector 14 is displayed on a monitor 15 or printed. This image may be saved in a computer or recorded on a video recorder. FIG. 2A shows a radiograph of small fish taken with about 9 keV monochromatized photon beam according to a known technique. The object to the detector is 0.3 m. FIG. 2B shows a radiograph of small fish taken with an unmonochromatized (white) photon beam in the embodiment according to this invention. The object to the detector is also 0.3 m. The image of FIG. 2A was obtained with an monochromatized photon beam with about 9 keV photon energy and 10 sec. exposure whereas the image of FIG. 2B was obtained with an unmonochromatized (white) photon beam and 10 ms exposure per image. The field of view was 300 xe2x96xa1m in both images. From the two radiographs, it is noted that the image of FIG. 2B shows the same resolution but much shorter exposure than that of FIG. 2A. Therefore, according to this embodiment of this invention, it is possible to image an object with high resolution and real-time response without any damage to the object. According to this invention, highly collimated and coherent X-ray sources provide an excellent solution to two major problems in radiography: poor contrast and poor lateral resolution. It is demonstrated that this solution can be implemented with high lateral resolution and fast time resolution, thereby opening the way to real-time microradiology investigations. The key factor in this novel radiology approach is to achieve contrast by using the refractive index rather than absorption. The corresponding mechanisms can be either edge diffraction or edge refraction. A simple, relatively inexpensive and reliable experimental setup which enables to test the approach in real-time investigations is developed. It is also demonstrated that real-time microradiology is feasible with the majority of the present synchrotron sources. A number of improvements that enhance our time-resolved approach are also considered and/or implemented. A lateral resolution of a few tenths of a micron can be expected by using a photoelectron-microscope-based detection technique. A better video camera would increase the number of pixels but possibly slow down the time per frame. Such improvements would also decrease the total equivalent radioactive dose in view of medical applications. The situation is already quite interesting in that regard, since the possibility to operate on small areas with microradiology decreases by at least six orders of magnitude the equivalent does with respect to a conventional 200xc3x97200 mm2 radiograph, taken with the same detection method and photon flux. In conclusion, successful tests of real-time microradiology with collimated synchrotron radiation, using an unmonochromatized (xe2x80x98whitexe2x80x99) X-ray beam and a simple and effective detection system are performed. The advantages of time resolution are too evident to need further comments. In particular, preliminary tests on live specimens raise the possibility of novel diagnostic applications of microradiology as well as of a variety of applications in the life sciences. The method for imaging an object according to the embodiments of this invention has the following benefits in contrast with those of prior art. 1. The image quality of radiography strongly depends on the quality of the optical element of the entire imaging system. The X-ray optics used to obtain xe2x80x9cphase contrastxe2x80x9d are typically difficult to make and to optimize. The deterioration of the optical properties of any of the X-ray optical elements in an optical path, will either greatly reduce the imaging quality or simply eliminate the xe2x80x9cphase contrastxe2x80x9d effect. This invention eliminates the necessity of using X-ray optics and can be applied to any small size collimated source. 2. This invention prevents the reduction in the X-ray intensity due to the X-ray optics. 3. This invention removes the necessity of using monochromatic X-ray for imaging. 4. This invention changes the photon energy spectrum that would be produced by absorbing optical elements, shifting its central photon energy to higher values. 5. According to this invention, a large fraction of the initial photon flux is used, thereby the time resolution and the lateral resolution are improved. The range of potential applications of the proposed imaging systems and methods of this invention is vast. The range spans the fields of materials science, manufacturing industry, geology, biological, biomedical and clinical medicine. In this disclosure, there is shown and described only the preferred embodiments of the invention, but, as aforementioned, it is to be understood that the invention is capable of use in various other combinations and environments and is capable of changes or modifications within the scope of the inventive concept as expressed herein.
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047160160	abstract	The universal fuel assembly has a plurality of elongated corner posts extending longitudinally between and releasably and rigidly interconnecting top and bottom nozzles so as to form a rigid structural skeleton of the fuel assembly. Additionally, a plurality of transverse grids are supported at axially spaced locations along the corner posts and a plurality of fuel rods are supported by the grids. Certain groups of the fuel rods are spaced apart laterally from one another by a greater distance than the rest of the fuel rods so as to define a number of elongated channels extending between the top and bottom nozzles. A cluster assembly having a cluster plate with a plurality of elongated rods is adapted to be removably supported on the top nozzle with its rods extending through the channels. The rods can be a plurality of guide thimbles in the case of one cluster assembly, or a plurality of oversized fuel rods in the case of another cluster assembly. The provision of cluster assemblies allows a unique scheme for loading fuel in the reactor core. Cluster assemblies containing burnt fuel can be loaded into fuel assemblies containing fresh fuel and vice versa. Also, a guide fixture mounting guide rods and a pair of comb devices mounting locking bars are utilized to depress springs within the cells of the grids in order to load fuel rods into the grid cells without scratching their exterior surfaces.
059109718	claims	1. A method of collecting molybdenum-99 from fission products produced in a nuclear reactor, the method comprising: providing a homogeneous solution nuclear reactor having a 20 to 100 kilowatt rating; using a uranyl sulfate solution as a homogeneous fissionable material in the reactor; running the reactor, thereby produce fission products including molybdenum-99 in the uranyl sulfate solution; shutting down the reactor and allowing it to cool down; pumping the uranyl sulfate solution from the top of the reactor through a heat exchanger means to cool the uranyl sulfate solution to below 30.degree. C.; passing the cooled uranyl sulfate solution to a column containing a sorbent for the selective absorption of Mo-99 and returning the non-absorbed portion of the uranyl sulfate back to the bottom of the reactor, the process continuing until substantially all of the uranyl sulfate solution has passed through the sorbent; thereafter passing water through the sorbent column, said water being derived from recombining the H.sub.2 and O.sub.2 gases given off during the running of the reactor to thereby maintain the concentration of the uranyl sulfate solution; and thereafter passing nitric acid through the sorbent to extract the Mo-99 from the sorbent and collecting the resulting solution in a separate container. a reactor vessel containing a selected quantity of uranyl sulfate solution as a homogeneous fissionable material for producing fission products including Mo-99; a sorbent column containing a sorbent capable of selectively absorbing Mo-99; heat exchanger means to cool a portion of said uranyl sulfate solution; means for directing a portion of said uranyl sulfate solution from the reactor vessel through said heat exchanger means and then through said sorbent column and thereafter back to the vessel; means for adding acid to said sorbent after substantially all of the uranyl sulfate solution has passed through the sorbent, thereby removing the absorbed Mo-99 from said sorbent; means to collect the Mo-99 removed from the sorbent. 2. The method of claim 1, wherein the sorbent is a composite ether of a maleic anhydride copolymer and .alpha.-benzoin-oxime. 3. The method of claim 2, wherein the acid passed through the sorbent is 10 molar nitric acid. 4. The method of claim 1, wherein the reactor is operated for a period between one and five days. 5. The method of claim 1, wherein the reactor contains about 20 liters of uranyl sulfate solution. 6. The method of claim 1, wherein the uranyl sulfate solution is passed through the sorbent column at a rate of about 1 to 10 milliliters per second. 7. A system for the collection of Mo-99 from fission products produced in a nuclear reactor, comprising: 8. The system of claim 7, wherein approximately 20 liters of uranyl sulfate solution is contained in the reactor. 9. The system of claim 7, wherein the reactor is operated from between 20 kW and 100 kW power rating. 10. The system of claim 7, wherein the sorbent is a composite ether of a maleic anhydride copolymer and .alpha.-benzoin-oxime. 11. The system of claim 10, wherein the acid passed through the sorbent is 10 molar nitric acid. 12. The system of claim 7, wherein the removed portion of the uranyl sulfate solution is cooled to below 40 degrees C. 13. The system of claim 7, wherein the uranyl sulfate solution is passed through the sorbent column at a rate of about 1 to 10 milliliters per second.
	claims	1. A mask apparatus for use in compressed sensing of incoming radiation, comprising:two or more coded masks having a body portion comprised of a material that modulates the intensity of the incoming radiation;wherein each of said masks has a plurality of mask aperture regions, that allow a higher transmission of the radiation relative to said body portion, the higher transmission being sufficient to allow reconstruction of compressed sensing measurements;wherein said coded masks are nested; andat least two of said coded masks are configured to rotate relative to one another. 2. The mask apparatus of claim 1, wherein:the coded masks are cylindrical. 3. The mask apparatus of claim 1, wherein:each of the coded masks has a top and a bottom, and the mask apparatus further comprises a radiation shield that modulates the intensity of the incoming radiation and that covers the top and bottom of the coded masks. 4. The mask apparatus of claim 1, wherein:each of the coded are hemispherical, segments of spheres, or spherical. 5. The mask apparatus of claim 1, wherein:the plurality of mask aperture regions of each of the coded masks are equal in number to a power of two. 6. The mask apparatus of claim 1, wherein:each of the coded masks is formed from a material selected from the group consisting of:tungsten, lead, gold, tantalum, hafnium and their alloys. 7. The mask apparatus of claim 1, wherein each of the coded masks is formed:i) from a material that modulates incoming gamma-ray radiation;ii) from a material that modulates incoming optical or infrared radiation;iii) formed from a material that modulates incoming neutron radiation; oriv) from a material that modulates both incoming gamma-ray radiation and neutrons. 8. The mask apparatus of claim 7, wherein:some of the mask aperture regions are modulating regions for gamma-rays and some of the mask aperture regions are modulating regions for neutrons. 9. The mask apparatus of claim 1, whereinthe coded masks are concentric. 10. The mask apparatus of claim 1, wherein the mask apparatus has two coded masks, wherein the two coded masks are configured to be rotated relative to one another. 11. The mask apparatus of claim 2, wherein the mask apparatus has a horizontal field of view of 360°. 12. The mask apparatus of claim 1, wherein the coded masks are hemispherical and the mask apparatus has a field of view of 2π or coded masks are spherical and the mask apparatus has a field of view of nearly 4π. 13. The mask apparatus of claim 1, further comprising a radiation shield formed of a material that modulates the intensity of the incoming radiation and that surrounds the coded masks;wherein the radiation shield has an opening that limits a field of view of a radiation sensor located within the one or more coded masks. 14. The mask apparatus as claimed in claim 13, wherein the radiation shield is cylindrical. 15. The mask apparatus as claimed in claim 14, wherein the radiation shield has an arcuate opening that limits the field of view of the radiation sensor to an arc defined by the opening. 16. The mask apparatus of claim 13, wherein each of the coded masks has a top and a bottom, and the mask apparatus further comprises a further radiation shield that modulates the intensity of the incoming radiation and that covers the top and bottom of the coded masks. 17. The mask apparatus according to claim 1, wherein said modulation comprises attenuating or scattering said incoming radiation. 18. The mask apparatus of claim 1, wherein at least one of said coded masks is arcuate, cylindrical, hemispherical, segments of spheres, or spherical. 19. A radiation detection method, comprising:making compressed sensing measurements of radiation from one or more radiation sources with at least one radiation sensor and a mask apparatus, the mask apparatus comprising:two or more coded masks having a body portion comprised of a material that modulates the intensity of incoming radiation, each of said one or more masks having a plurality of mask aperture regions that allow a higher transmission of the radiation relative to said body portion, the higher transmission being sufficient to allow reconstruction of compressed sensing measurements;wherein one or more of the coded masks is configured to rotate; andat least two of the coded masks are configured to rotate relative to one another;wherein the incoming radiation from the one or more radiation sources passes through the coded masks before detection by the at least one radiation sensor. 20. A method of decommissioning, decontamination, environmental monitoring, medical imaging, astronomy or security, comprising a radiation detection method as claimed in claim 19. 21. A radiation detection method as claimed in claim 19, wherein each of the one or more masks is arcuate, cylindrical, hemispherical, segments of spheres, or spherical. 22. A compressed sensing radiation imager, comprising:at least one radiation sensor located within a mask apparatus that comprises:two or more coded masks having a body portion comprised of a material that modulates the intensity of incoming radiation, each of said two or more coded masks having a plurality of mask aperture regions that allow a higher transmission of the radiation relative to said body portion, the higher transmission being sufficient to allow reconstruction of compressed sensing measurements;wherein one or more of the coded masks is configured to rotate; and at least two of the coded masks are configured to rotate relative to one another;wherein the imager is configured to make compressed sensing measurements of radiation from one or more radiation sources and to generate radiation image data from the compressed sensing measurements. 23. A radiation imager as claimed in claim 21, wherein the at least one radiation sensor comprises:i) at least one gamma-ray radiation sensor, such that the radiation imager constitutes a gamma-ray radiation imager;ii) at least one neutron sensor, such that the radiation imager constitutes a neutron radiation imager;iii) at least one gamma-ray radiation sensor and at least one neutron radiation sensor, such that the radiation imager constitutes a gamma-ray radiation and neutron radiation imager;iv) at least one dual modality sensor; orv) at least one dual modality sensor senses both gamma-rays and neutrons. 24. A radiation imager as claimed in claim 22, further configured to capture an optical, infrared or other wavelength image and to output image data. 25. A radiation imager as claimed in claim 22, wherein the imager is configured to overlay the radiation image data and an optical or infrared image corresponding to a common field of view. 26. The radiation imager according to claim 22, wherein the coded masks are nested. 27. A compressed sensing radiation imager as claimed in claim 22, wherein each of the one or more masks are arcuate, cylindrical, hemispherical, segments of spheres, or spherical.
	abstract	Systems and methods that facilitate non-pertubative measurements of low and null magnetic field in high temperature plasmas.
	abstract	An X-ray tube (3) is rotated about its focal point along a plane perpendicular to a body axis of a patient by an X-ray tube rotation driver and thus the X-ray irradiation field moves. When the side of the X-ray irradiation field reaches an edge detector (6a) in the edge part of the flat panel detector, the edge detector detects X-ray and provides a signal to a controller. The controller controls the X-ray limiting device (4a) to move shield blades thereof to limit the range of the X-ray irradiation field. The above structure makes it possible to move the center of the X-ray irradiation field without moving the patient and also to prevent the X-ray irradiation field from going outside of the flat panel detector.
	description	A transponder card for a nuclear reactor control rod drive control system is described below in more detail. The transponder card permits continued system operation in the event of a failure of transponder card circuitry that controls the movement of the control rods. The transponder card is configured to detect failures of its rod control circuitry and prevent inadvertent incremental rod insertion without depending on the Rod Control system to remove power from the transponder card. Further, the transponder card can announce to the Rod Control system via a bit on a serial data word that the transponder card has detected a defect in itself. Referring to the drawings, FIG. 1 is a sectional view, with parts cut away, of a boiling water nuclear reactor pressure vessel (RPV) 10. RPV 10 has a generally cylindrical shape and is closed at one end by a bottom head 12 and at its other end by a removable top head 14. A side wall 16 extends from bottom head 12 to top head 14. Side wall 16 includes a top flange 18. Top head 14 is attached to top flange 18. A cylindrically shaped core shroud 20 surrounds a reactor core 22. Shroud 20 is supported at one end by a shroud support 24 and includes an opposed removable shroud head 26. An annulus 28 is formed between shroud 20 and side wall 16. A pump deck 30, which has a ring shape, extends between shroud support 24 and RPV side wall 16. Pump deck 30 includes a plurality of circular openings 32, with each opening housing a jet pump 34. Jet pumps 34 are circumferentially distributed around core shroud 20. An inlet riser pipe 36 is coupled to two jet pumps 34 by a transition assembly 38. Each jet pump 34 includes an inlet mixer 40, and a diffuser 42. Inlet riser 36 and two connected jet pumps 34 form a jet pump assembly 44. Heat is generated within core 22, which includes fuel bundles 46 of fissionable material. Water circulated up through core 22 is at least partially converted to steam. Steam separators 48 separates steam from water, which is recirculated. Steam dryers 50 remove residual water from the steam. The steam exits RPV 10 through a steam outlet 52 near vessel top head 14. The amount of heat generated in core 22 is regulated by inserting and withdrawing a plurality of control rods 54 of neutron absorbing material, for example, hafnium. To the extent that control rod 54 is inserted into fuel bundle 46, it absorbs neutrons that would otherwise be available to promote the chain reaction which generates heat in core 22. Control rod 54 couples with a control rod drive (CRD) 58 which moves control rod 54 relative to a core plate 64 and fuel bundles 46. CRD 58 extends through bottom head 12 and is enclosed in a control rod drive housing 66. A control rod guide tube 56 extends vertically from control rod drive mechanism housing 66 to core plate 64. Control rod guide tubes 56 restrict non-vertical motion of control rods 54 during control rod 54 insertion and withdrawal. FIG. 2 is a simplified block diagram of a control rod drive control system (RDCS) 70 in accordance with an embodiment of the present invention. RDCS 70 includes central rod processing circuitry or control processor 72 that is operationally coupled to a branch amplifier card 74 that is operationally coupled to a transponder card 76. Particularly, in one embodiment, branch amplifier card 74 and transponder card 76 are operationally coupled to control processor 72 via serial digital electronic communication. Branch amplifier card 74 and transponder card 76 are part of a hydraulic control unit (HCU) 78. HCU 78 includes a plurality of transponder cards 76 arranged in clusters of several transponder cards 76 coupled to a branch amplifier card 74. Branch amplifier card 74 serves, in part, to distribute command (CMD) words it receives from central rod processing circuitry 72 to transponder cards 76 within its cluster and to the next downstream branch amplifier card 74. In a reverse manner, acknowledge (ACK) words are routed within a cluster to the cluster""s branch amplifier card 74. Each branch amplifier card 74, in turn, routes the ACK work to a branch amplifier card 74 further upstream and back to control processor 72. With reference to FIG. 3, in an exemplary embodiment, RDCS 70 enables a plant operator to select and maneuver control rods and display rod positions at all times. It includes a set of components, both in the control room and inside the containment, that generate, check and distribute digital electronic messages (xe2x80x9cwordsxe2x80x9d) sent from an operator""s console 80 to hydraulic control units 82 and from rod position probes 84 back to console 80. A general overview of the operation of the RDCS 70 is as follows. The plant operator selects the rod or rods to move at rod interface system (RIS) bench-board console 80. Request words are sent to two redundant rod action control system (RACS) cabinets 86 and 88. Each RACS cabinet 86 and 88 independently evaluates the operator""s request to insure that the desired rod motion will result in a permissible control rod pattern. Validated requests are transmitted to a rod drive system (RDS) cabinet 90. RDS cabinet 90 compares the validated rod movement commands from the two RACS cabinets 86 and 88 and, if they agree, sends CMD words to a set of hydraulic control rod drive units 78 via clusters of branch junction amplifier cards 74 and transponder cards 76. A plurality of position probes 94 underneath pressure vessel 10 measure control rod 54 positions and send probe word messages to two redundant rod position multiplexer (MUX) cabinets 96 and 98. RACS cabinets 86 and 88 independently compare measured rod positions against allowed rod pattern configurations. RACS cabinets 86 and 88 send position information to RDS cabinet 90 for further transmittal to an operator""s display 100 on RIS console 80. RDS cabinet 90 sends position data to a plant process computer (not shown) by means of Process words sent via a computer interface module 102. HCU transponder card 76 is configured to receive and buffer CMD words on to downstream transponder cards 76 in the same cluster. Transponder card 76 is also configured to compare a command address embedded in the CMD word with the transponder card""s own unique identification card address. If the addresses compare (agree), then the command bits of the CMD word are decoded and the appropriate directional control valve solenoid 92 is energized. Transponder card 76 is also configured to transmit its own ACK word to the next upstream transponder card 76. If the addresses do not compare, then transponder card 76 passes any signal on the ACK input to the ACK output. Each transponder card 76 also is configured to generate valve activity bits based on its monitoring of HCU directional control valve solenoid circuits for continuity and energization. Further, each transponder card is configured to generate an ACK word composed of an identification card address, directional valve activity bits, HCU status bits, and transponder trouble bits. Each transponder 76 is configured to receive as input CMD words from the upstream transponder card or a branch amplifier card 74, ACK words from the downstream transponder card, and HCU 78 status. HCU 76 status includes: Both scram valves not fully closed Scram accumulator trouble (N2 gas pressure low or water on the gas side of the accumulator piston) Both scram test switches not in xe2x80x9cNormalxe2x80x9d AC voltage from the downstream transponder card Each transponder card 76 is configured to output CMD words to the downstream transponder and ACK words to the upstream transponder or branch amplifier card. Further, each transponder card 76 is configured to output switched AC voltage to the directional control valve solenoids and AC voltage to the downstream voltage. Any suitable AC voltage can be used, for example, 120 volts AC at 60 Hz or 12 volts AC at 50 Hz. Of course, AC voltages higher or lower than 120 volts AC can be used. The CMD word is composed of a 32-bit serial word transmitted as a serial data stream. This data stream can be divided into 8 defined sections. The data bit transmission rate is 312.5 kHz (3.2 xcexcs), which results in a 102.4 xcexcs of total word length. FIG. 4 shows an exemplary embodiment of a CMD word and Table I provides the description of the CMD word shown in FIG. 4. The Received Synchronization prime is sent prior to CMD Synchronization bit. The state of prime bits is xe2x80x9c1xe2x80x9d. The CMD Synchronization bit is set at xe2x80x9c0xe2x80x9d state. When the transponder card receives this bit, it indicates that the row address will be received on the next bit. Each Transponder has its own ID number corresponding to the plant arrangement of HCUs. Each ID number is composed by row and column address corresponding to the X and Y coordinates of the plant arrangement. The Space bit is sent to separate the ID number from command bits. The state of space bit is set at xe2x80x9c0xe2x80x9d. When the ID number matches with a particular transponder, the ACK word is generated at this point. The Withdraw Supply and Insert/Withdraw Exhaust bits of the CMD word are dynamically encoded. When the Transponder receives command bits for HCU directional control valve activation, the succeeding word""s command bits are required to be encoded with the complement of previous word""s command bits. If the succeeding word""s command bits are not encoded as complement of previous command bits, the activated control valve will be timed out (de-energized). Table II shows the logical values of the command bit that cause the activation to occur. The Margin set of bits is set at xe2x80x9c0xe2x80x9d state, and is sent prior to the received synchronization bits. The purpose of the margin bits is to permit the transponder card to complete the transmission of the ACK word. The ACK word is also composed of a 32-bit serial data stream. This data stream can be divided into eight sections. The data transmission rate is 312.5 kHz (3.2 xcexcs), which results in 102.4 xcexcs of total word length. FIG. 5 shows an exemplary embodiment of an ACK word and Table III provides the description of the ACK word shown in FIG. 5. In conjunction with the Synchronization bit, the Transmitted Synchronization Prime Bits serves to provide a means for the receiving circuitry to synchronize its reception to the word being received in order to interpret the bit meanings correctly. Ten consecutive xe2x80x9c1xe2x80x9d states are required to synchronize the receiving circuitry. The ACK Synchronization bit is set at xe2x80x9c0xe2x80x9d. This bit in conjunction with the Transmitted Synchronization Prime is used to synchronize the receiving circuitry to the word being received. Each Transponder has its own ID number corresponding to the plant arrangement of HCUs. Each ID number is composed by row and column address corresponding to the X and Y coordinates of the plant arrangement. The Space bit is sent to separate the ID number from the Directional Valve Status Bits. The state of space bit is set at xe2x80x9c0xe2x80x9d. The Direction Valve Status Bits contains four bits, and provides the activation status of directional valves. The status of each valve is given by the following two equations. SET (xe2x80x9c1xe2x80x9d State)=(Input power is above AC peak) AND (solenoid valve circuitry has continuity) AND (solenoid valve is de-energized) RESET (xe2x80x9c0xe2x80x9d State)=(Input power is near 0 volt) OR (solenoid valve circuitry is opened) OR (solenoid valve is energized) The HCU status contains three bits, and provides the test switch, HCU accumulator pressure and scram valve position. The Transponder removes power to the solenoid and sets the Transponder Trouble flag to xe2x80x9c1xe2x80x9d if the Transponder detects energization of a directional control solenoid without an appropriate command. HCU transponder card 76 includes a self-testing function that uses solid-state relays in each of the valve control circuits to interrupt the current through the directional valve solenoids if the self-testing circuitry detects a disagreement between the valve monitoring circuitry and the command word received by the card. In other words, if the valve is energized with no command, the self-test circuitry removes power to the valve solenoid after a short time delay by turning off the solid-state relay that is in series with the valve current path. Once the HCU Transponder self-test circuitry detects an agreement between the CMD word and the valve activity, the solid-state relay will again be energized and allow the transponder to operate properly. An Analyzer Card in central rod processing circuitry 72 interrogates the HCU Transponder at intervals as part of a self-testing program. Failure of a Transponder to encode a proper ACK word is detected immediately in the control room and indicated through an annunciation window alarm. The self-test feature of the HCU Transponder 76 detects and prevents operation of a control rod directional control solenoid without an appropriate command from the Rod Drive Control System. A secondary self-test feature of the HCU Transponder is to detect most single component failure modes that would prevent activation of the back-up solenoid de-energization circuitry. HCU Transponder 76 removes power to the solenoid and sets the xe2x80x9cTransponder Troublexe2x80x9d flag (serial word bit) to a logic xe2x80x9conexe2x80x9d if HCU transponder 76 detects energization of a directional control solenoid without an appropriate command. The xe2x80x9cTransponder Troublexe2x80x9d flag occupies the two-bit locations reserved for the Pn and Pp bits added to the Acknowledge word by branch amplifier card 74. If a momentary short turns on the valve control solenoid but is subsequently removed, transponder 76 will remove power to the valve circuit by dc-energizing the solid state relay. Every two minutes, the Analyzer Card will retest the failed Transponder Card. Retesting of the valve control solenoid by the Analyzer Card will provide an agreement between the disconnected state of the valve control monitoring circuitry (appears to the valve monitoring circuitry as energized) and the Analyzer xe2x80x9ctestxe2x80x9d Command word. The self-test circuitry in transponder 76 will again energize the solid-state relay and permit the transponder control circuitry to energize the directional valve solenoid upon command. With control returned to the valve energization circuitry, transponder 76 again operates in a normal manner. While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.
	description	The following application claims priority to U.S. Provisional Application Ser. No. 62/342,028, filed May 26, 2016 and is incorporated by reference in its entirety. Contained herein is material that is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the United States Patent and Trademark Office patent file or records, but otherwise reserves all rights to the copyright whatsoever. The following notice applies to the software, screenshots and data as described below and in the drawings hereto and All Rights Reserved. This disclosure relates generally to modular shielding for storage containers, particularly for storage containers comprising substances that either emit unwanted elements, compounds, or materials to the environment, or require protection from the environment. Certain elements, compounds, or materials radiate unwanted or harmful components when stored. One example of this type of material is nuclear waste. Nuclear waste currently in storage comes from three principal sources: spent fuel from commercial or research reactors, liquid waste from the reprocessing of spent fuel, and waste from the nuclear weapons and propulsions industry. Most of the storage concerns relate to so-called ‘intermediate and high level’ nuclear waste components, which are highly radioactive, often requiring cooling and containment because their decay gives off heat and radiation, and have an extremely long half-life. Long-term storage of radioactive waste is aided by the stabilization of the waste into a form which will neither react nor degrade for extended periods of time. Currently, vitrification is an accepted practice to achieve this stabilization. The vitrification process requires nuclear waste to be mixed with glass forming media (soil or zeolite, as an example), and heated to the point that the mixture melts. Once cooled, the result is that the nuclear waste is effectively entrained in glass, with reduced chances of leakage and exposure to the environment. Some vitrification methods allow the vitrification process to occur in the actual storage container, thereby minimizing waste handling and reducing contamination possibilities from processing. This type of vitrification is known as in-container vitrification, or ICV™. The containers used for this process are called ICV™ Containers. Once processed through vitrification, the ICV™ containers are stored, either temporarily or long term. Shielding is used to mitigate potential harmful energy from the radioactive decay of certain elements. Within current shielding for ICV™ storage systems there is little room for reconfiguration and adjustability of the shielding. Additionally, with current systems more shielding is being used than is necessary which is not economical both from materials and storage capacity standpoints. The converse can be true, i.e. some stored compounds or materials need shielding from the environment around them. What is needed is an adjustable, compact, modular shielding system for short or long-term storage containers requiring shielding to prevent either the escape of the contents, particles, or rays, or prevent the ingress of particles or rays to the container. So as to reduce the complexity and length of the Detailed Specification, Applicant(s) herein expressly incorporate(s) by reference all of the following materials identified in each paragraph below. The incorporated materials are not necessarily “prior art” and Applicant(s) expressly reserve(s) the right to swear behind any of the incorporated materials. System for Vitrification Container with Removable Shield Panels, Ser. No. 62/342,028, filed May 26, 2016, which is herein incorporated by reference in its entirety, and to which this application claims priority. System and Method for a Robotic Manipulator Arm, Ser. No. 15/591,978 filed May 10, 2017, with a priority date of May 16, 2016, which is hereby incorporated by reference in its entirety. Mobile Processing System, Ser. No. 14/748,535, filed Jun. 24, 2015, with a priority date of Jun. 24, 2014, which is herein incorporated by reference in its entirety. Ion Specific Media Removal from Vessel for Vitrification, Ser. No. 15/012,101 filed Feb. 1, 2016, with a priority date of Feb. 1, 2015, which is hereby incorporated by reference in its entirety. System and Method for an Electrode Seal Assembly, Ser. No. 15/388,299 filed Dec. 22, 2016, with a priority date of Dec. 29, 2015, which is herein incorporated by reference in its entirety. Methods for Melting of Materials to be Treated, Pat. No. 7,211,038 filed Mar. 25, 2001, with a priority date of Sep. 25, 2001, which is herein incorporated by reference in its entirety. Methods for Melting of Materials to be Treated, Pat. No. 7,429,239 filed Apr. 27, 2007, with a priority date of Sep. 25, 2001, which is herein incorporated by reference in its entirety. Vitrification of Waste with Continuous Filling and Sequential Melting, U.S. Pat. No. 6,283,908 filed May 4, 2000, with a priority date of May 4, 2000, which is herein incorporated by reference in its entirety. Applicant(s) believe(s) that the material incorporated above is “non-essential” in accordance with 37 CFR 1.57, because it is referred to for purposes of indicating the background or illustrating the state of the art. However, if the Examiner believes that any of the above-incorporated material constitutes “essential material” within the meaning of 37 CFR 1.57(c)(1)-(3), applicant(s) will amend the specification to expressly recite the essential material that is incorporated by reference as allowed by the applicable rules. Aspects and applications presented here are described below in the drawings and detailed description. Unless specifically noted, it is intended that the words and phrases in the specification and the claims be given their plain, ordinary, and accustomed meaning to those of ordinary skill in the applicable arts. The inventors are fully aware that they can be their own lexicographers if desired. The inventors expressly elect, as their own lexicographers, to use only the plain and ordinary meaning of terms in the specification and claims unless they clearly state otherwise and then further, expressly set forth the “special” definition of that term and explain how it differs from the plain and ordinary meaning. Absent such clear statements of intent to apply a “special” definition, it is the inventors' intent and desire that the simple, plain and ordinary meaning to the terms be applied to the interpretation of the specification and claims. The inventors are also aware of the normal precepts of English grammar. Thus, if a noun, term, or phrase is intended to be further characterized, specified, or narrowed in some way, then such noun, term, or phrase will expressly include additional adjectives, descriptive terms, or other modifiers in accordance with the normal precepts of English grammar. Absent the use of such adjectives, descriptive terms, or modifiers, it is the intent that such nouns, terms, or phrases be given their plain, and ordinary English meaning to those skilled in the applicable arts as set forth above. Further, the inventors are fully informed of the standards and application of the special provisions of 35 U.S.C. § 112, ¶6. Thus, the use of the words “function,” “means” or “step” in the Detailed Description or Description of the Drawings or claims is not intended to somehow indicate a desire to invoke the special provisions of 35 U.S.C. § 112, ¶6, to define the systems, methods, processes, and/or apparatuses disclosed herein. To the contrary, if the provisions of 35 U.S.C. § 112, ¶6 are sought to be invoked to define the embodiments, the claims will specifically and expressly state the exact phrases “means for” or “step for, and will also recite the word “function” (i.e., will state “means for performing the function of . . . ”), without also reciting in such phrases any structure, material or act in support of the function. Thus, even when the claims recite a “means for performing the function of . . . ” or “step for performing the function of . . . ”, if the claims also recite any structure, material or acts in support of that means or step, or that perform the recited function, then it is the clear intention of the inventors not to invoke the provisions of 35 U.S.C. § 112, ¶6. Moreover, even if the provisions of 35 U.S.C. § 112, ¶6 are invoked to define the claimed embodiments, it is intended that the embodiments not be limited only to the specific structure, material or acts that are described in the preferred embodiments, but in addition, include any and all structures, materials or acts that perform the claimed function as described in alternative embodiments or forms, or that are well known present or later-developed, equivalent structures, material or acts for performing the claimed function. Elements and acts in the figures are illustrated for simplicity and have not necessarily been rendered according to any particular sequence or embodiment. In the following description, and for the purposes of explanation, numerous specific details, process durations, and/or specific formula values are set forth in order to provide a thorough understanding of the various aspects of exemplary embodiments. However, it will be understood by those skilled in the relevant arts, that the apparatus, systems, and methods herein may be practiced without these specific details, process durations, and/or specific formula values. It is to be understood that other embodiments may be utilized and structural and functional changes may be made without departing from the scope of the apparatus, systems, and methods herein. In other instances, known structures and devices are shown or discussed more generally in order to avoid obscuring the exemplary embodiments. In many cases, a description of the operation is sufficient to enable one to implement the various forms, particularly when the operation is to be implemented in software. It should be noted that there are many different and alternative configurations, devices, and technologies to which the disclosed embodiments may be applied. The full scope of the embodiments is not limited to the examples that are described below. In the following examples of the illustrated embodiments, references are made to the accompanying drawings which form a part hereof, and in which is shown by way of illustration various embodiments in which the systems, methods, processes, and/or apparatuses disclosed herein may be practiced. It is to be understood that other embodiments may be utilized and structural and functional changes may be made without departing from the scope. A removable shield panel (RSP) system is described herein for providing modular, reusable shielding to storage containers. The system provides a flexible approach to allow expanding storage requirements while minimizing shielding needs. The RSP system is capable of shielding any number and configuration of containers while reducing the amount of shielding materials, reducing storage footprint, and allowing for simple reconfiguration. In some embodiments, the RSP system may be applied to the nuclear waste storage containers, including, for instance, In-Container Vitrification™ (ICV™) containers. FIG. 1 depicts a cross-section of an embodiment of an ICV™ container 399. Vitrification is the process by which a vitrified product with embedded contaminants is formed. Vitrification is the gold standard for long-term waste disposal due to the very low leachability of contamination out of the vitrified product. ICV™ is a system wherein the vitrification occurs in a one-time use or a reusable container. In some embodiments, the container is used only once for vitrification and serves as the final storage container. In some embodiments, a container may serve as the treatment and storage container for a vitrified waste form resulting from the treatment of solid wastes (ion-specific media (ISM), sludge, liquid processing waste, soils, ash, decontamination, and decommissioning wastes, etc.). The ICV™ container 399 depicted in FIG. 1 comprises outer shielding 457, refractory lining 431, feed port 411, starter path (not shown), electrodes 421, and lid (built in hood) 458. In some embodiments, the outer shielding 457 is composed of a metal such as steel. The lid 458 may comprise one or more electrode penetration/seal 415 assemblies that keep electrodes 421 in contact with the starter path while providing electrical insulation between the electrodes 421 and the ICV™ container 399. The ICV™ container 399 is described in more detail in Ion Specific Media Removal from Vessel for Vitrification, Ser. No. 15/012,101 filed Feb. 1, 2016, with a priority date of Feb. 1, 2015, which is hereby incorporated by reference in its entirety. The depicted embodiments show ICV™ containers as example storage containers. It should be clear that the containers are not necessarily ICV™ containers and may take other forms. The same principles and design aspects may be applied to many different styles and configurations of containers. The term “container” as used herein may refer to an ICV™ container or any other container type or style that may utilize the shielding principles and/or designs disclosed herein. While vitrified nuclear waste is disclosed as an example material requiring shielding in storage it should be clear that the same principles may be applied to other waste forms and other materials requiring shielding. For instance, in a temperature controlled facility the shielding may be used as thermal insulation. Electromagnetic shielding may be used for redirecting magnetic flux, and radio frequency shielding may be used to block radio waves. Other embodiments are contemplated. FIG. 2 depicts an isometric view of an embodiment of an ICV™ container 400. The depicted embodiment is a variation of the ICV™ container 399 depicted in FIG. 1, modified for the installation of a removable shield panel embodiment. The modifications comprise the addition of one or more shield mounting points 125 to facilitate mounting of shield panels. The shield mounting points 125 may vary in quantity, location, and form between various embodiments. Some embodiments of the shield panels may not require shield mounting points on the ICV™ container 400. In some embodiments, shield panels may be attached to the storage containers using one or more coupling mechanisms including magnetics, tongue and groove, suction cups, and Velcro®, among others. FIG. 3 depicts the modified ICV™ container 400 embodiment of FIG. 2 with shield mounts 125 and shield panels 100. Each container 400 may comprise one or more shield mounting points 125 on each side. In the depicted embodiment, each container 400 comprises two shield mounting points 125 on each side of the top of the container 400 for a total of eight shield mounting points 125 per container 400. The type, geometry, quantity, and location of the shield mounting points 125 may vary between embodiments. Shield mounts 150 are shaped to engage with the shield mounting points 125 on the container 400. In the depicted embodiment, a single container 400 is shielded on all sides. When containers 400 are stored they are generally stacked and layered. The internal containers 400 in a storage configuration often do not require individual shielding because shielding is at least partially provided by adjacent containers 400. When the containers 400 are stored together generally only the sides of the outermost containers 400 that are exposed to the storage environment require shielding. The RSP system may be used to shield external sides of stored containers thus reducing the amount of shielding required in a storage facility. As the number of containers 400 in a storage facility increases or decreases, the shielding of the outermost containers 400 may be easily adjusted by moving the removable shield panels 100 and preinstalling them on the exposed container 400 surfaces. FIGS. 4 and 5 depict single layer container 400 configurations where the shield panels 100 are mounted on only the outermost (exposed) surfaces of the containers 400 and secured with shield mounts 150. Top shield panels may be used to cover the top of the uppermost layer of containers 400. FIG. 6 depicts an example embodiment of a layer of ICV™ containers 400 containing vitrified nuclear waste. Nuclear waste is often classified by activity level with the common levels being low, intermediate, and high activity waste. Low activity waste generally requires little or no shielding whereas high activity waste may require a large amount of shielding. In the depicted embodiment, the containers 400 are filled with different classes of nuclear waste. The innermost container 400 is high (H) level and the surrounding containers 400 are intermediate (I) level. This embodiment illustrates how a lower level waste (the intermediate waste) can be used as shielding for higher level waste thus reducing shielding requirements in the storage facility. Reducing the amount of shielding reduces the storage footprint of each container 400 thus increasing capacity and efficiency of a storage facility. Additionally, the RSP system decouples the shielding from the container 400 from a weight standpoint thereby potentially increasing the amount of material that can be stored in each container 400. In some embodiments, the containers 400 may be stacked in two or more layers to minimize storage footprint and maximize storage capacity. FIGS. 7 and 8 depict ICV™ containers 400 in example stacked configurations with mounted removable shield panels 100 and top shield panels 200, secured with shield mounts 150. While the depicted embodiments comprise two layers it should be clear that the containers may be stored in other configurations included one or more layers. FIG. 9A depicts an embodiment of a generic removable shield panel 100. FIG. 9B depicts an example shield panel 100a comprising tabbed edges 915 which may overlap to prevent gaps between shield panels 100a when they are used side by side. Removable shield panels 100 may be composed of a wide range of materials which may be dependent upon the shielding's purpose. Shield panels 100 may vary in thickness and/or comprise layers of different materials. FIG. 9C depicts a top down cross-sectional view of an example shield panel 100c comprising three layers 72, 73, and 74 of differing materials. Different embodiments may comprise varying numbers and thicknesses of layers of one or more different materials. For example, in nuclear waste storage, shield panels 100 may comprise one or more layers of materials including one or more of concrete, steel, lead, and mullite refractory, among others, to reduce radiation dosage rates. In some embodiments, steel shield panels have a half-value layer of 16 mm for Cs-137/Ba-137m radiation. Other half-value layer configurations are possible. In temperature-controlled facilities shield panels may comprise thermal insulation material(s). In some embodiments, shield panels may be composed of, or comprise a layer of, a bumper or impact resistant material to protect storage contents from impact. Shield panels may comprise conductive or magnetic materials, such as copper in some embodiments, to shield storage contents from electromagnetic flux. In some embodiments, shield panels may comprise multiple layers of differing materials operable to provide shielding of one or more different types. For example, electronic equipment may utilize shield panels that comprise at least a thermal shield layer and an electromagnetic shield layer. In some embodiments, one or more shield panels or materials therein may be layered wherein they connect using an interlocking concept similar to LEGOs® such that layers may be added and removed without modification to the shielding mounts. In some embodiments, one or more shield panels or materials therein may be layered wherein they connect using one or more of magnetism, suction, Velcro®, or other removable connection types known in the art. In some embodiments, such as the embodiment depicted in FIG. 10A, shield panels 100 may comprise circuitry 99 including temperature control mechanisms for providing cooling or heating to storage containers. In such embodiments, shield panels 100 may comprise electric circuit connectors 98 such that the connectors 98 align for simple connection during setup/reconfiguration. In some embodiments, such as for temporary storage and/or transportation, each shield panel may comprise standalone temperature control mechanisms. In some embodiments, shield panels may be hollow or comprise channels in the side facing the containers to reduce weight and/or to allow controlled airflow around the storage containers. In some embodiments, shield panels may comprise one or more sensors. Sensors may serve to alert in the event of leakage, temperatures outside acceptable ranges, vibration, radiation, and other conditions that may be detrimental to the stored materials, the environment, and/or workers. In some embodiments, the shield panels may further comprise one or more mechanisms to facilitate placement, lifting, and removal. The mechanisms may take the form of hooks, handles, recesses, and magnetic connectors, among others. The one or more mechanisms may, when not in use, lay flush with, recessed from, or protruding from the surface of the shield panel, in some embodiments. FIG. 10B depicts the removable shield panel embodiment of FIG. 9A further comprising example hooks, handles, and magnetic connectors to facilitate reconfiguration. The depicted placement facilitation mechanisms are shown for example purposes only. The particular combination, types, amount, positioning, geometry, and sizes of the depicted mechanisms may vary between embodiments. In the embodiment depicted in FIG. 10B, the shield panel 100c comprises three example shield placement facilitation mechanisms: recesses 64, magnetic connectors 65, hook 66, and handles 67. The recesses 64 may provide surfaces in the shield panel 100c upon which an upward force may be applied for lifting and repositioning the shield panel 100c. Magnetic connectors 65 may provide areas or sections of the shield panel 100c which are magnetic such that a magnetic force may be applied to lift and transport the shield panel 100c. Hook 66 may be hinged such that it may fold upwards when needed to lift the shield panel 100c and down against or recessed into the shield panel 100c when not in use. Handles 67 may fold outwards or slide upwards from the shield panel 100c as needed. In some embodiments, corner shielding may be provided along the edges to cover any gaps that may exist between side shield panels 100 (FIG. 9A) and between top panels and side shield panels 100 (FIG. 9A). FIG. 11 depicts an embodiment for example corner shielding types. Corner 815 shows overlapping side shield panels 100 secured to container 400 with shield mounts 150. Corner 845 shows corner shielding that may be used for tabbed shield panels (FIG. 9B). Corner 825 is a simple L shaped overlapping corner piece. Corner 805 is a simple square cross-section panel. Corner 835 is a combination of corner 805 and 825. In some embodiments, corner shielding may be attached to the shield panels using one or more coupling mechanisms including magnetics, tongue and groove, dovetail joints, suction cups, and Velcro®, among others. FIG. 12A depicts an alternate embodiment of a side shield 100d with mounting points 131 for additional shield mounts 150 (FIG. 12B) on both the top and bottom sides of the shield 100d for added stability and easier reconfiguration. In some embodiments, bottom shield mounts and mounting points 131 may be the same or similar geometry as top shield mounts and mounting points 130. FIG. 12B depicts the shield panel 100d in use. In some embodiments, bottom shield mounts 131 may mount orthogonally or at an angle from the side rather than from the bottom such that they may be removed without having to lift or move the container. The addition of bottom mounts 131 may require a pull and lift force in order to remove the shield panels 100d. Adding an extra force for removal increases stability, thus reducing chances of slippage over time or slippage due to outside forces or impacts such as earthquakes. FIG. 13 depicts an embodiment that utilizes bottom shields 201 in similar geometry as the top shields 200. In some embodiments, top shields 200 and bottom shields 201 may be incorporated with the side shields 100 to completely shield one or more containers. In some embodiments, the shield mount may be designed to secure a combination of one or more side shields 100, top shields 200, and bottom shield 201 together forming an enclosure for housing one or more containers. In some embodiments, bottom shielding is not required as the floor of the storage facility may provide adequate shielding. In some embodiments, bottom shielding may be in the form of a continuous pad or section of flooring. FIG. 14 depicts an embodiment of a shield mount 150. The depicted shield mount 150 comprises slots 124 and 126 where slot 124 fits over a mount point on the modified ICV™ container and slot 126 fits over a mount point in the shield panel. The slotted mounting mechanism facilitates simple mounting of shield panels and allows the shield panels to be easily lifted upwards for removal. When the shield mount 150 is placed correctly and completely the top surface 121 is flush with the top of the container and the outer surface 127 is flush with the outer surface of the shield panel, in some embodiments. In some embodiments, one or both of surface 121 and surface 127 may be either recessed or protruding. The filleted corners 120 allow for the shield mount 150 to be easily removed by hand or hand tool, if necessary. Typically the shield panels may be removed and reconfigured remotely. In some embodiments, one or more of the shield mounts 150 may be integrated with the shields. In some embodiments, a crane and/or robotic manipulator arm may be used as an apparatus for shield reconfiguration wherein the apparatus may be locally or remotely controlled. Some embodiments may utilize a robotic remote control system for shield reconfiguration. An example of such a robotic control system may be found in co-pending U.S. patent application Ser. No. 15/591,978, entitled System and Method for a Robotic Manipulator Arm, filed May 10, 2017, with a priority date of May 16, 2016, which is hereby incorporated by reference in its entirety elsewhere in this document. FIGS. 15A through 15C depict a variation of the shield mount embodiment of FIG. 14. The shield mount 150a has many of the same features as the shield mount 150 depicted in FIG. 14. Shield mount 150a has a closed slot 126a where shield mount 150 (FIG. 14) has an open slot 126 (FIG. 14). FIG. 15B and FIG. 15C depict the shield mount 150a in use. Closed slot 126a fits over guide 112 in the shield panel 100. In the depicted embodiment, the shield mount 150a is slidably attached to the shield panel 100 where slot 126a slides along guide 112. FIGS. 15D and 15E depict an embodiment of a shield panel 100 corresponding to the shield mount embodiment of FIGS. 15A through 15C. In some embodiments, the shield mount 150a may be fixed to the shield panel 100. The guide 112 keeps the shield mount 150a aligned and prevents the shield mount 150a from being separated from the shield panel 100. In FIG. 15B the shield mount 150a is fully engaged with the shield panel 100 and the container 400. In FIG. 15C the shield mount 150a is extended from the shield panel 100 and the container 400. The shield panel system allows for simple adjustment of shield thickness as necessary. For instance, in nuclear waste storage embodiments, shield thickness may require adjustment to maintain dose at acceptable limits (such as 1 mSv/hr on contact). In some embodiments, containers may be stored such that the higher activity containers are stored innermost and lower activity containers are stored outermost to increase shielding of the higher activity containers. If additional shielding is required the panels can be stacked to increase the shield thickness. FIG. 16A depicts an embodiment of an adjustable shield mount 500 that can be adjusted for different shield thicknesses. The positions of the shield mounting peg 530 and container mounting peg 520 can be adjusted by sliding them along the length of the cut channel 515 to compensate for varying shield thicknesses. In some embodiments, the shield mounting peg 530 and the container mounting peg 520 may be a single component. In the depicted embodiment nuts are used to tighten and secure the mounting pegs in position; however, other fastening mechanisms may be used. FIG. 16B depicts the adjustable shield mount 500 in use with a thick shield 100e. In some embodiments, the adjustable shield mount 500 may further comprise a toggle clamp or other such clamping or securing mechanism. FIG. 17A depicts an embodiment of an adjustable shield mount 550 that can accommodate two shields of different thicknesses. The positions of both shield mounting pegs 530 and the container mounting peg 520 can be adjusted by sliding them along the length of the cut channel 515 to compensate for varying shield thicknesses. In some embodiments, the container mounting peg and the nearest shield mounting peg 530 may be a single component. FIG. 17B depicts the adjustable shield mount 550 in use with two shield panels 100. In the depicted embodiment, the shield panels 100 are the same thickness; however, they may be different thicknesses in other embodiments. In the depicted embodiment, nuts are used to tighten and secure the mounting pegs in position; however, other fastening mechanisms may be used. In some embodiments, the adjustable shield mount 550 may further comprise a toggle clamp or other such clamping or securing mechanism. FIG. 18 depicts an example embodiment of a layer of ICV™ containers 400 containing vitrified nuclear waste. In the depicted embodiment, the containers 400 are filled with different classes of nuclear waste. Those marked H contain high level waste and those marked I contain intermediate level waste. Generally in storage configurations containing different waste levels the lower level waste may be used as shielding for the higher level waste, such as the example embodiment depicted in FIG. 6. When it is not possible to use the lower level waste as additional shielding against the higher level waste different types, thickness, and/or layers of shielding may be needed on the higher level waste than on the lower level waste. In the depicted embodiment, all of the same shields are used; however, the shielding is doubled on the higher-level waste. This is an example of when it is useful to have adjustable shield mounts capable of accommodating different numbers and thicknesses of shield panels 100. FIGS. 19A through 19C are described as a group. FIG. 19A depicts an isometric view of an embodiment of a shield mount 150a that utilizes a toggle clamp mechanism 300 to secure a modified shield panel 100f (FIG. 19C). The toggle clamp 300 fits over the base of the shield mount 150a and allows the shield mount 150a to be secured to the shield panel 100f and the top of the ICV™ container 400 with a clamp mechanism 300 to prevent the shield from slipping downward. FIG. 19B depicts a side view of the shield mount 150a. FIG. 19C depicts the shield mount 150a in use with modified shield panels 100f. In an embodiment, the size and materials used for clamp mechanism 300 may vary based on the size and composition of the shield panel. It should be clear that a 5000-pound shield panel may require sturdier and larger materials for clamp mechanism 300 than a 100-pound shield panel. FIG. 20 depicts an embodiment of an adjustable shield mount 500a that incorporates the use of a toggle clamp system 300 for securing shield panels of varying thicknesses. The depicted embodiment incorporates the shield mounting peg 530 and the container mounting peg 520 to accommodate shield panels of varying thicknesses. FIG. 21A depicts an embodiment of a shield mount 700 that secures the side shields 100f (FIG. 21C) with a top shield 200a (FIG. 21B). The shield mount 700 comprises an edge gripper 720 which may be used to secure the top shield 200a (FIG. 21B) in place via clamping force and friction. In the depicted embodiment, the edge gripper 720 is fastened to the end of the shield mount 700. In some embodiments, the edge gripper 720 may be integrated to the shield mount 700. In some embodiments, the shield mount may be integrated to the top shield 200. FIG. 21B depicts an embodiment of a top shield 200a that couples with the shield mount embodiment 700. FIG. 21C depicts the top shield embodiment 200a in use with the shield mount 700 and shield panel 100f. In some embodiments, the top shield 200a is sized to fit just over the container lid. Example Embodiment In an example embodiment, there are one or more storage containers. When there is more than one container the containers may be placed in close proximity to one another to reduce overall storage footprint. This generally means that one or more faces of the storage containers may be in contact with, or very close to, one or more faces of other storage containers in a storage configuration. In some embodiments, shielding is not required on the internal faces in the storage configuration. The exposed faces (external or outermost) of the storage containers in the storage configurations may require shielding. One or more modular shield panels may be applied to the exposed faces to provide shielding to the storage configuration. FIGS. 22A through 22C depict a storage configuration during and after reconfiguration. FIG. 22A depicts a storage configuration comprising eight storage containers 400. In the depicted embodiment, the visible storage container 400 is about to be removed from the storage configuration. In preparation for removal of the visible storage container 400 top shield panel 8 (FIG. 22C) has been removed and shield panels 6 and 7 are shown in the process of being removed. FIG. 22B depicts the storage configuration of FIG. 22A when the shield panels 6, 7, and 8 (FIG. 22C) and the storage container 400 (FIG. 22A) have been removed exposing faces 36, 37, and 38. FIG. 22C depicts the storage configuration of FIG. 22B after shield panels 6, 7, and 8 have been installed on the exposed faces 36, 37, and 38 of the storage containers. Example Embodiment Figures, figure elements, and written disclosure related to the following embodiment are described in detail in the above disclosure. The RSP system allows for modular reconfigurable shielding for one or more storage containers. In an example embodiment, there are a plurality of unshielded storage containers containing nuclear waste. In industry, any container for storing nuclear waste normally comprises, as part of its structure (i.e. not removable), the required shielding for the particular waste level contained therein to keep the radiation dosage below predetermined safety limits. In this example embodiment the nuclear waste storage containers are unshielded i.e. they can be used to store any level of nuclear waste because the shielding required for a particular waste level is not included as part of their structure. These unshielded nuclear waste storage containers are modular and reconfigurable because they can contain any waste level and appropriate shielding can be added as needed based on predetermined dosage requirements for a given storage facility. In the example embodiment, each unshielded nuclear waste storage container comprises at least one mounting point for mounting one or more modular shield panels to it. Each modular shield panel comprises at least one mounting point for mounting to an unshielded nuclear waste storage container. Depending on the number of shield panels required and the number of shield mounts on the shield panels and the containers, one or more shield mounts may be used to couple with the mounting points on the shield panels and the containers to attach the shield panels to the containers. In some embodiments, one or more of the shield mounts may be adjustable to accommodate shield panels of varying thicknesses. In the example embodiment, a plurality of nuclear waste storage containers may be stored together. When stored together the sides adjacent to (face-to-face with) other storage containers do not require shielding while, depending on the waste levels contained therein, and the predetermined dosage requirements for the particular storage facility, the outermost (external) faces of the storage containers may require shielding. The sides of the containers that are placed adjacent to other containers do not require additional shielding because the shielding on that side is provided by the neighboring container. Continuing with the example embodiment, when the storage containers are placed in a storage configuration and all of the external facing sides of the containers are shielded according to the requirements of the particular waste level and/or storage facility the storage configuration is considered to be fully shielded. When an additional unshielded storage container needs to be added to the storage configuration, depending on the layout of the existing configuration, one or more shield panels may be removed from one or more storage containers in the configuration resulting in one or more partially shielded storage containers. The additional unshielded storage container may then be placed in the configuration adjacent to one or more partially shielded storage containers in the configuration. One or more of the previously removed one or more shield panels may then be installed on the external faces of the newly added storage container. If any faces are still exposed (unshielded) additional shield panels may be installed as needed to result in a fully shielded storage configuration. It should be clear that any one or more aspects of the disclosed shield panels, shield mounts, and shielding configurations may be combined to form other embodiments not expressly disclosed herein. Additionally, the shield mounts may take other geometries and utilize fasteners different than those depicted. For the sake of convenience, the operations are described as various interconnected functional blocks or distinct software modules. However, this is not necessary, and there may be cases where these functional blocks or modules are equivalently aggregated into a single logic device, program or operation with unclear boundaries. In any event, the functional blocks and software modules or described features can be implemented by themselves, or in combination with other operations in either hardware or software. Having described and illustrated the principles of the systems, methods, processes, and/or apparatuses disclosed herein in a preferred embodiment thereof, it should be apparent that the systems, methods, processes, and/or apparatuses may be modified in arrangement and detail without departing from such principles. Claim is made to all modifications and variation coming within the spirit and scope of the following claims.
050248049	summary	BACKGROUND OF THE INVENTION The present invention relates to nuclear power plants and more particularly to systems for supporting a pressure relief and safety valve system above a pressurizer vessel in a pressurized water nuclear power plant. A pressurizer vessel is used in a pressurized water nuclear reactor power plant to provide relief for plant coolant overpressure. Usually, such a pressurizer vessel is a vertical, thick walled unit having a hemispherical top or dome, and having its bottom end supported by a flanged skirt. Relief valves provide a first level of overpressure protection and safety valves provide a second or backup level of overpressure protection. The pressurizer relief and safety valve system includes a manifold or header assembly and piping connections to nozzles in the head of the pressurizer and to discharge outlets. One situation where overpressure protection is needed, for example, is where the entire plant electrical load has been dumped because of electrical operating conditions. The entire pressurizer valve system must be safely and reliably supported above the pressurizer in accordance with plant safety and performance standards. In earlier plant designs, valve support systems were excessively costly because the valve support system designs were plant dependent. Subsequently, a basic valve support system-was developed for use as a standardized scheme for supporting pressurizer valves and piping in variously designed pressurized water reactor plants. That basic support system is disclosed in U.S. Pat. No. 4,426,350 entitled VALVE SUPPORT ARRANGEMENT FOR PRESSURIZED IN NUCLEAR POWER PLANT, issued to M. J. Zegar et al. on Jan. 17, 1984 and assigned to the present assignee. In the Zegar patent, an arrangement for supporting the pressurizer safety and relief valve system is described including a common header supported relative to the side walls of the pressurizer vessel by the use of columnar supports secured to the header and to the pressurizer side wall by the use of lug means. The lug means are attached to the pressurizer side wall and must be capable of supporting the load of the columnar supports and pressurizer safety and relief valve system. One disadvantage of Zegar support system was that the vessel support lugs had to be large to avoid overstressing from some combinations of load forces under various operating conditions. The vessel wall itself is thus undesirably subjected to heavy load forces under various conditions. Generally, rigid valve system support is required for dynamic forces such as those stemming from an earthquake. At the same time, flexible support is required to accommodate thermal growth or contraction of the valve system due to changing temperature conditions. The transmittal of large load forces to the vessel lugs in Zegar occurs because all vertical and horizontal load forces and moments about all three reference axes are transmitted to the vessel support lugs. Continuing development effort accordingly led to subsequent improvements as set forth in U.S. Pat. No. 4,576,788 entitled STRADDLE-TYPE SUPPORT STRUCTURE FOR NUCLEAR POWER PLANT PRESSURIZER VALVES, issued to R. M. Blaushild on Mar. 18, 1986 and assigned to the present assignee and U.S. Pat. No. 4,629,601 entitled STIRRUP-TYPE SUPPORT STRUCTURE FOR NUCLEAR POWER PLANT PRESSURIZER VALVES, issued to R. M. Blaushild on Dec. 16, 1986 and assigned to the present assignee. In the straddle-type valve support system, the vessel lugs are subjected only to horizontal forces which tend to rotate the lower support ring on which columnar valve supports rest. All other load forces are applied to arcuate sections that interconnect the lower and upper support rings, thereby distributing such forces over the vessel head surface. Heavy loading of the vessel lugs is eliminated, but much more extensive support structure is required and accessibility for inspecting vessel welds is difficult and time consuming. In the stirrup-type valve support system, some improvement is achieved in lug loading through even distribution of loading forces from the columnar supports to the vessel lugs through a ring girder. The columnar supports are secured to the girder at points spaced from the points at which the girder is secured to the vessel lugs thereby enabling the lug loading forces to be distributed more evenly. While disassembly of the stirrup-type girder-vessel lug securance is facilitated to enhance vessel head accessibility for weld inspection, overall vessel head access for weld inspections is still difficult and time consuming because of the visual obstruction presented by the relatively complex valve support system structure with the valve support system left in place or, alternatively, because of the overall difficulty of support structure disassembly for more open access to the vessel head. In all of the prior art pressurizer valve support systems there has been little or no provision for accommodating unit to unit manufacturing differences such as vessel lug hole locations, etc. There has accordingly continued to be a need for further improvement in the support of a pressurizer safety relief valve system in nuclear power plants. The present invention is directed to achieving significant improvement in pressurizer valve support systems through simpler, more economic structure that provides better vessel head accessibility for weld inspections while meeting valve support safety and performance requirements. SUMMARY OF THE INVENTION An arrangement is provided for supporting a relief and safety valve system for a pressurizer in a nuclear power plant. The pressurizer has a generally cylindrical vessel wall topped with a dome-like member. The valve system includes a manifold generally located above and extending about the periphery of the vessel wall of the pressurizer. The valve supporting arrangement comprises a plurality of lug means extending outwardly from and secured to the vessel wall at points spaced around the wall periphery. Columnar support means extends generally vertically upward from each of the lug means to the valve system manifold. A first elongated and generally cylindrical structural member extends generally in the horizontal direction to support the lower end of each of the columnar support means relative to the associated lug means. A plurality of collar means project downwardly from the manifold for securance of the manifold to the columnar support means. A second elongated and generally cylindrical structural member extends generally in the horizontal direction to support the upper end of each of the columnar support means relative to the associated manifold collar means. One of the elongated structural members of each of the columnar support means is disengageable from its securance so that each of the columnar support means can be pivoted about its other elongated structural member and swung outwardly from the vessel.
	abstract	A MgF2—CaF2 binary system sintered body for a radiation moderator having a compact polycrystalline structure excellent in radiation moderation performance, especially neutron moderation performance, comprises MgF2 containing CaF2 from 0.2% by weight to 90% by weight inclusive, having a bulk density of 2.96 g/cm3 or more, and a bending strength of 15 MPa or more and a Vickers hardness of 90 or more as regards mechanical strengths.
060350113	abstract	A reactor core for a boiling water nuclear reactor includes a plurality of fuel assemblies (40) with a plurality of vertical fuel rods (10) and possibly occasional vertical water-filled rods or channels (32, 48, 49, 50, 51) which are surrounded by a fuel channel (1). Between the fuel assemblies (40) there are arranged water gaps (37a, 37b). At least one fuel assembly (40) has at least one outer, reduced corner portion (41) facing a gap (37a, 37bb), and the number of fuel rods (10) in each such fuel assembly (40) is reduced by a number corresponding to the number of reduced corner portions (41) therein.
	claims	1. A method to analyze crystals in a deposit on a surface of a nuclear generating station heating surface, comprising the steps of:extracting a deposit from the surface of the nuclear generating station heating surface;preparing a sample of material from the deposit for testing, wherein the sample of material is configured to examine at least one of said crystals in its environment within the deposit such that an as found state of the extracted deposit can be tested;conducting at least one of a high resolution scanning electron microscope/energy dispersive X-ray spectrometry of the sample and a scanning transmission electron microscope/selected area electron diffraction/spot and elemental mapping analysis of the sample;if high resolution scanning microscope/energy dispersive X-ray spectrometry is conducted, further comprising the steps of:conducting at least one of three-dimensional morphology, surface topography aggregation and determination of flake size/shape, phase separation and chemical composition quantification after the high resolution scanning electron microscope/energy dispersive X-ray spectrometry of the sample;performing a Monte Carlo simulation of electron beam-specimen interaction after the at least one of three-dimensional morphology, surface topography aggregation and determination of flake size/shape, phase separation and chemical composition quantification; andstoring results of the Monte Carlo simulation and the at least one of the high resolution scanning electron microscope/energy dispersive X-ray spectrometry of the sample, the three-dimensional morphology, surface topography aggregation and determination of flake size/shape, phase separation and chemical composition quantification in a structural data base;if high resolution scanning microscope/energy dispersive X-ray spectrometry is not conducted, further comprising the steps of:conducting at least one of an internal structure, morphology and crystal size/shape determination, a crystallography investigation and a chemical composition investigation after the scanning transmission electron microscope/selected area electron diffraction/spot and elemental mapping analysis of the sample; andstoring results of the at least one of the internal structure, morphology and crystal size/shape determination, crystallography investigation and the chemical composition investigation in a crystallographic data system. 2. The method according to claim 1, wherein the Monte Carlo simulation predicts an expected behavior of the sample under specific operating conditions. 3. The method according to claim 1, wherein the step of preparing the sample of material comprises one of:collecting a CRUD deposit directly on TEM grids placed on filter paper and placing the deposit on standard carbon support film to dislodge a number of crystals from a surface of a flake of the deposit. 4. The method according to claim 1, wherein the step of conducting at least one of three-dimensional morphology, surface topography aggregation and determination of flake size/shape, phase separation and chemical composition quantification after the high resolution scanning electron microscope/energy dispersive X-ray spectrometry of the sample is performed by alternating between imaging modes to eliminate charging effects resulting from a radioactive field developed during analysis. 5. The method according to claim 1, wherein one of the three-dimensional morphology and the phase separation is determined through scanning electron microscope multimode imaging. 6. The method according to claim 1, wherein a peak to background method is used during the step of conducting at least one of a high resolution scanning electron microscope/energy dispersive X-ray spectrometry of the sample to compensate for geometric effects of the sample surface. 7. The method according to claim 1, wherein both a high resolution scanning electron microscope/energy dispersive X-ray spectrometry of the sample and a scanning transmission electron microscope/selected area electron diffraction/spot and elemental analysis of the sample are performed. 8. The method according to claim 1, wherein the high resolution scanning electron microscope/energy dispersive X-ray spectrometry is used to identify phase separation according to an average atomic number of the sample. 9. The method according to claim 1, wherein scanning electron microscopy/energy dispersive X-ray spectrometry is used at both a voltage between 0.2 to 5 kV for one of radioactive and charged samples, and at voltages between 20 to 50 kV when obtaining chemical information in the high resolution scanning electron microscope/energy dispersive S-ray spectrometry. 10. The method according to claim 1, wherein the energy dispersive X-ray spectrometry is performed with standards for radioactive samples. 11. The method according to claim 1, wherein a peak to background method is used during the scanning electron microscope/energy dispersive X-ray spectrometry of the sample to compensate for geometric effects of the deposit. 12. The method according to claim 1, further comprising:conducting transmission electron microscopy of the sample. 13. The method according to claim 12, wherein a selected area electron diffraction is performed during the step of transmission electron microscopy to determine d-spacings of crystal phases of the sample. 14. The method according to claim 1, further comprising:comparing the stored results of the one of high resolution scanning electron microscopy/energy dispersive X-ray spectrometry of the sample and the scanning transmission electron microscopy/selected area electron diffraction/spot and elemental mapping to a crystallographic materials phase data system. 15. The method according to claim 1, wherein both high resolution scanning electron microscope/energy dispersive X-ray spectrometry of the sample and scanning transmission electron microscope/selected area electron diffraction/spot and elemental mapping analysis of the sample are conducted, and wherein the method further comprises the steps of:conducting at least one of an internal structure, morphology and crystal size/shape determination a crystallography investigation and a chemical composition investigation after the scanning transmission electron microscope/selected area electron diffraction/spot and elemental mapping analysis of the sample; and,storing results of the at least one of the internal structure, morphology and crystal size/shape determination, crystallography investigation and the chemical composition investigation in a crystallographic data system.
	claims	1. A system for preventing and monitoring a leakage of water from a tank liner at a storage tank, the system comprising:a concrete reservoir;the tank liner made up of a wall liner that is formed by coupling a plurality of first panels and is attached to an inner wall of the concrete reservoir, and a floor liner that is formed by coupling a plurality of second panels, is attached to a floor of the concrete reservoir, and is coupled to the wall liner by welding;a leaking water collecting plate formed by welding a plurality of third panels and inserted between the floor liner and the floor of the concrete reservoir; andan edge leaking water collecting channel buried in an edge of the storage tank and configured to collect leaking water discharged between the floor liner and the leaking water collecting plate. 2. The system according to claim 1, further comprising a wall leaking water collecting channel that is buried in a wall of the concrete reservoir on an outer surface of the wall liner, is formed along a weld zone between the first panels at a long length, and is coupled to the edge leaking water collecting channel at a lower portion thereof. 3. The system according to claim 2, further comprising an air injection unit made up of a pneumatic device configured to inject compressed air into the edge leaking water collecting channel or the wall leaking water collecting channel and a pressure gauge configured to measure an internal pressure of the edge leaking water collecting channel or the wall leaking water collecting channel. 4. The system according to claim 1, further comprising a coupler that is buried in the floor of the concrete reservoir floor at a lower portion thereof, protrudes to correspond to a thickness of the third panel at an upper portion thereof, is formed as long as a length of the third panel, and is coupled with the third panels by welding the third panels at opposite upper sides thereof. 5. The system according to claim 4, wherein a weld zone between the second panels is disposed above the coupler in a length direction of the coupler, and the coupler serves as a floor leaking water collecting channel with a cross-section that is formed as a channel whose upper portion is open. 6. The system according to claim 4, wherein a weld zone between the second panels is disposed above the coupler in a length direction of the coupler, and the coupler serves as a floor coupling block as an inside thereof is formed in a solid block form. 7. The system according to claim 1, further comprising a heavy structure support that is buried in the floor of the concrete reservoir at a lower portion thereof, protrudes to correspond to a length adding up thicknesses of the second and third panels at an upper portion thereof, passes through the second and third panels to expose an upper surface thereof to the floor of the storage tank, and is welded to the second and third panels at an upper edge thereof. 8. The system according to claim 1, further comprising a through part that has a cylindrical sleeve formed by extending up to a lower portion of the concrete reservoir and is welded to the second and third panels at an upper edge thereof, the cylindrical sleeve being buried in the floor of the concrete reservoir at a lower portion thereof, protruding to correspond to a length adding up thicknesses of the second and third panels at an upper portion thereof, passing through the second and third panels to expose an upper surface thereof to the floor of the storage tank, being provided with a hollow channel vertically passing through the center thereof, and having an upper portion of the hollow channel communicating with an inside of the storage tank. 9. A method for preventing and monitoring a leakage of water from a tank liner at a storage tank,the storage tank including:a concrete reservoir;the tank liner made up of a wall liner that is formed by coupling a plurality of first panels and is attached to an inner wall of the concrete reservoir, and a floor liner that is formed by coupling a plurality of second panels, is attached to a floor of the concrete reservoir, and is coupled to the wall liner by welding;a leaking water collecting plate formed by welding a plurality of third panels and inserted between the floor liner and the floor of the concrete reservoir; andan edge leaking water collecting channel buried in an edge of the storage tank and configured to collect leaking water discharged between the floor liner and the leaking water collecting plate,the method comprising installing the third panels for collecting leaking water between a bottom of the floor liner and the floor of the concrete reservoir, causing the leaking water generated from the floor liner to flow to a gap between the floor liner and the leaking water collecting plate, and collecting the leaking water at the edge leaking water collecting channel. 10. The method according to claim 9, the storage tank further including a wall leaking water collecting channel that is buried in a wall of the concrete reservoir on an outer surface of the wall liner,the method further comprising, before the collecting of the leaking water, connecting a pneumatic device to the edge leaking water collecting channel or the wall leaking water collecting channel, injecting a predetermined amount of air into a leaking water passage formed by connecting the edge leaking water collecting channel, the wall leaking water collecting channel, and the gap between the floor liner and the leaking water collecting plate, and observing a change in pressure of the air inside the leaking water passage to detect whether or not the leakage of water occurs. 11. The method according to claim 10, further comprising, between the collecting of the leaking water and the detecting of whether or not the leakage of water occurs, if air bubbles are formed in the storage tank by injecting the air into the leaking water passage using the pneumatic device when generation of the leakage of water is detected by the change in pressure of the air inside the leaking water passage, specifying a point to which the air bubbles are discharged to ascertain a leak.
	description	This application hereby claims the benefit of U.S. Patent Application No. 61/141,698 for a UVLED Apparatus for Curing Glass-Fiber Coatings (filed Dec. 31, 2008), which is hereby incorporated by reference in its entirety. The present invention embraces an apparatus and a method for curing coatings on drawn glass fibers. Glass fibers are typically protected from external forces with one or more coating layers. Typically, two or more layers of coatings are applied during the optical-fiber drawing process (i.e., whereby a glass fiber is drawn from an optical preform in a drawing tower). A softer inner coating layer typically helps to protect the glass fiber from microbending. A harder outer coating layer typically is used to provide additional protection and to facilitate handling of the glass fiber. The coating layers may be cured, for example, using heat or ultraviolet (UV) light. UV curing requires that the coated glass fiber be exposed to high intensity UV radiation. Curing time can be reduced by exposing the coating to higher intensity UV radiation. Reducing curing time is particularly desirable to permit an increase in fiber drawing line speeds and thus optical-fiber production rates. Mercury lamps (e.g., high pressure mercury lamps or mercury xenon lamps) are commonly used to generate the UV radiation needed for UV curing. One downside of using mercury lamps is that mercury lamps require a significant amount of power to generate sufficiently intense UV radiation. For example, UV lamps used to cure a single coated fiber (i.e., one polymeric coating) may require a collective power consumption of 50 kilowatts. Another shortcoming of mercury lamps is that much of the energy used for powering mercury lamps is emitted not as UV radiation, but rather as heat. Accordingly, mercury lamps must be cooled (e.g., using a heat exchanger) to prevent overheating. In addition, the undesirable heat generated by the mercury lamps may slow the rate at which the optical fiber coatings cure. Furthermore, mercury lamps generate a wide spectrum of electromagnetic radiation, such as having wavelengths of less than 200 nanometers and greater than 700 nanometers (i.e., infrared light). Typically, UV radiation having wavelengths of between about 300 nanometers and 400 nanometers is useful for curing UV coatings. Thus, much of the electromagnetic radiation generated by mercury bulbs is wasted (e.g., 90 percent or more). Additionally, glass fibers possess an exemplary diameter of about 125 microns, which, of course, is much smaller than the mercury bulbs. Consequently, most of the UV radiation emitted by the mercury lamps does not reach the glass fiber's uncured coating (i.e., the energy is wasted). It may thus be advantageous to employ UVLEDs, an alternative to conventional mercury lamps, to cure glass-fiber coatings. UVLEDs typically require significantly less energy and correspondingly generate much less heat energy than conventional UV lamps. For example, U.S. Pat. No. 7,022,382 (Khudyakov et al.), which is hereby incorporated by reference in its entirety, discloses the use of UV lasers (e.g., continuous or pulsed lasers) for curing optical fiber coatings. U.S. Patent Application Publication No. 2003/0026919 (Kojima et al.), which is hereby incorporated by reference in its entirety, discloses the use of ultraviolet light emitting diodes (UVLEDs) for curing optical fiber coatings. The disclosed optical fiber resin coating apparatus includes a mold assembly in which a UV curable resin is coated onto an optical fiber. Also at the mold assembly, the coated optical fiber is exposed to UV radiation from a number of UVLEDs to cure the UV coating. A control circuit may be used to control the UV radiation output from the UVLED array. For example, the control circuit may reduce the current to one or more UVLEDs to reduce the intensity of emitted UV radiation. The control circuit may also be used to vary the intensity of the UV radiation as the optical fiber progresses through the mold assembly. Even so, UVLEDs, though more efficient than mercury lamps, still waste a significant amount of energy in curing glass-fiber coatings. In particular, much of the emitted UV radiation is not used to cure the glass-fiber coatings. Therefore, a need exists for a UVLED apparatus that, as compared with a conventional mercury-lamp device, not only consumes less power and generates less unwanted heat, but also is capable of curing glass-fiber coatings with improved curing efficiency. Accordingly, the invention embraces a UVLED apparatus and associated method for curing in situ optical-fiber coating. The apparatus and method employ one or more UVLEDs that emit electromagnetic radiation into a curing space. An incompletely cured, coated glass fiber passes through the curing space, thereby absorbing electromagnetic radiation to effect curing of the optical-fiber coating. An exemplary UVLED apparatus includes one or more UVLED-mirror pairs. Each UVLED-mirror pair includes one or more UVLEDs capable of emitting electromagnetic radiation and one or more mirrors (or other reflective surfaces) that are capable of reflecting electromagnetic radiation. The UVLED(s) and corresponding mirror(s) are positioned apart from one another so as to define a curing space. As noted, this curing space permits the passage of a coated glass fiber between the UVLED(s) and the mirror(s). Moreover, the mirror(s) are typically positioned opposite corresponding UVLED(s) to efficiently reflect the electromagnetic radiation emitted from the UVLED(s) (and not already absorbed by the glass-fiber coating) into the curing space. In another aspect, the present invention embraces a method for curing a coating on a glass fiber. UV radiation is emitted from one or more sources of electromagnetic radiation toward a curing space. A portion of the emitted UV radiation is transmitted entirely through the curing space. At least some of the UV radiation transmitted entirely through the curing space is reflected toward the curing space (e.g., with a mirror). A glass fiber having an incompletely cured coating is passed through the curing space to effect the absorption of both emitted and reflected UV radiation, thereby curing the coated glass fiber. The foregoing illustrative summary, as well as other exemplary objectives and/or advantages of the invention, and the manner in which the same are accomplished, are further explained within the following detailed description and its accompanying drawings. In one aspect, the present invention embraces an apparatus for curing glass-fiber coatings. The apparatus employs one or more UVLEDs that are configured to emit electromagnetic radiation toward a drawn glass fiber to cure its coating(s), typically polymeric coatings. In this regard, a plurality of UV lamps may be positioned in various configurations, such as an apparatus 10 containing opposing UVLEDs 11 schematically depicted in FIG. 1 and an apparatus 20 containing staggered UVLEDs 11 depicted in FIG. 2. The UVLEDs 11 define a curing space 15 having a central axis 14 along which an optical fiber (i.e., a glass fiber having one or more coating layers) may pass during the curing process. A heat sink 12 may be positioned adjacent to each UVLED 11 to dissipate generated heat energy. A mounting plate 13 provides structural support for the UVLEDs 11. In one exemplary embodiment, the apparatus for curing glass-fiber coatings includes at least a UVLED-mirror pair, which includes (i) an ultraviolet light emitting diode (UVLED) and (ii) a mirror (e.g., a concave mirror) that is positioned to reflect and focus the UV-radiation emitted by the UVLED. FIG. 3 schematically depicts an apparatus 30 containing a plurality of UVLED-mirror pairs. As depicted in FIG. 3, the UVLEDs 11 and corresponding mirrors 16 define a space through which the coated glass fiber can pass (i.e., a curing space 15). This curing space 15 further defines a central axis 14, typically the axis along which a drawn glass fiber passes during the curing process (i.e., the glass fiber's curing axis). Although the central axis 14 is typically vertical, non-vertical (e.g., horizontal) arrangements of the central axis 14 may also be used. Moreover, although the central axis may be centrally positioned in the curing space, a central axis that is not centrally positioned within the curing space is within the scope of the present invention. Each UVLED 11 may be positioned such that it emits UV radiation toward the central axis 14. In this regard, those of ordinary skill will appreciate that the power per unit area (i.e., the radiant flux) emitted by a UVLED decreases exponentially as the distance of the UVLED from the optical fiber increases. Accordingly, each UVLED may be positioned at a distance of between about 1 millimeter and 100 millimeters (e.g., typically between about 5 millimeters and 20 millimeters) from the optical fiber to be cured (e.g., from the central axis). Typically, a UVLED and its corresponding mirror are positioned so that a substantial portion of the UV radiation incident to the optical fiber is substantially perpendicular to the optical fiber (i.e., incident at about a 90 degree angle). Alternatively, the UVLED and/or its corresponding mirror may be positioned at an angle so that most of the UV radiation incident to the optical fiber is incident at an angle other than 90 degrees. FIG. 5 schematically depicts an apparatus 50 containing UVLEDs 11 and mirrors 16 positioned at an angle (i.e., an angle other than 90 degrees relative to the optical fiber and the central axis 14). It may be desirable for the power of the UV radiation incident to the optical fiber to vary as the optical fiber progresses through the apparatus. Varying the power of the UV radiation may aid in the curing of the glass-fiber coating. Depending on the curing properties of a particular coating, it may be desirable to initially expose the optical fiber to high intensity UV radiation. Alternatively, it may be desirable to initially expose the optical fiber to lower intensity UV radiation (e.g., between about 10 percent and 50 percent of the maximum exposure intensity) before exposing the optical fiber to high intensity UV radiation (e.g., the maximum intensity to which the optical fiber is exposed). In this regard, initially exposing the optical fiber to lower intensity UV radiation may be useful in controlling the generation of free radicals in an uncured coating. Those of ordinary skill in the art will appreciate that if too many free radicals are present, many of the free radicals may recombine rather than encourage the polymerization of the glass-fiber coating—an undesirable effect. Varying the intensity of the UV radiation may, for example, be achieved by positioning the UVLED at an angle. As noted, the intensity of the UV radiation incident to a portion of the optical fiber may vary depending upon the distance from that portion to the UVLED. Alternatively, in an apparatus containing a plurality of UVLEDs the intensity of the UV radiation output from the UVLEDs may vary. As noted, each UVLED may be positioned such that it emits UV radiation toward the central axis. That said, it will be appreciated by those of ordinary skill in the art that a UVLED does not emit UV radiation only toward a point or line, but rather emits UV radiation in many directions. Thus, most of the UV radiation emitted by a UVLED will not strike the glass-fiber coating to effect curing. However, in curing an optical fiber coating, it is desirable that as much UV radiation as possible strikes the optical fiber (i.e., a coated glass fiber). In this regard, it will be further appreciated by those of ordinary skill in the art that curing occurs when UV radiation is absorbed by photoinitiators in the glass-fiber coating. Thus, a UVLED may have one or more associated reflectors that focus emitted UV radiation toward the central axis. For example, FIG. 6 depicts a cross-sectional view of a UVLED 11 having an attached reflector 17. The reflector 17 may, for example and as depicted in FIG. 6, have the shape of a rotated teardrop curve. By having a teardrop shape, the reflector focuses UV radiation having various angles of emittance toward the central axis. That said, the present invention embraces UVLEDs with associated reflectors of various shapes (e.g., a spherical, elliptical, cylindrical or parabolic mirror). A UVLED may have one or more lenses attached for focusing UV radiation emitted by the UVLED toward the central axis. Typically, a lens for focusing electromagnetic radiation is convex (e.g., biconvex or plano-convex). In an alternative embodiment, a Fresnel lens may be employed. Moreover, the lens may be selected such that the lens has a focal point at the glass fiber's curing axis (e.g., the central axis). One or more mirrors may be positioned opposite a UVLED (i.e., on the opposite side of the central axis) so as to reflect the UV radiation emitted by the UVLED in the general direction of the central axis. In other words, a UVLED emits UV radiation toward the curing space and the central axis, and its corresponding mirror(s) reflect emitted UV radiation not initially absorbed by optical fiber coatings back toward the central axis (e.g., the glass fiber's curing axis). In this respect, FIG. 3 depicts UVLEDs 11 having a mirror 16 positioned opposite the central axis 14. Typically a mirror will be larger than its corresponding UVLED. For example, a mirror may have a height of between about one inch and 1.5 inches; however, other mirror sizes are within the scope of the present invention. The mirror may be formed from a suitable reflective material. For example, the mirror may be formed from polished aluminum, polished stainless steel, or metalized glass (e.g., silvered quartz). The mirror may have a concave shape (i.e., the mirror is curved inwards toward the curing space) so that the mirror focuses UV radiation emitted by the UVLED toward the central axis. By way of example, a concave mirror may have, inter alia, a cylindrical, elliptical, spherical, or parabolic shape (e.g., a paraboloid or a parabolic cylinder). A concave mirror can focus otherwise lost UV radiation (e.g., UV radiation not initially incident to an optical fiber to be cured) onto an optical fiber for curing, thus limiting the amount of wasted energy. A UVLED-mirror pair as used herein is not limited to a single UVLED paired with a single mirror in a one-to-one relationship. A UVLED-mirror pair may include a plurality of UVLEDs. Alternatively, a UVLED-mirror pair may include a plurality of mirrors. UVLEDs are capable of emitting wavelengths within a much smaller spectrum than conventional UV lamps. This promotes the use of more of the emitted electromagnetic radiation for curing. In this regard, a UVLED for use in the present invention may be any suitable LED that emits electromagnetic radiation having wavelengths of between about 200 nanometers and 600 nanometers. By way of example, the UVLED may emit electromagnetic radiation having wavelengths of between about 200 nanometers and 450 nanometers (e.g., between about 250 nanometers and 400 nanometers). In a particular exemplary embodiment, the UVLED may emit electromagnetic radiation having wavelengths of between about 300 nanometers and 400 nanometers. In another particular exemplary embodiment, the UVLED may emit electromagnetic radiation having wavelengths of between about 350 nanometers and 425 nanometers. As noted, a UVLED typically emits a narrow band of electromagnetic radiation. For example, the UVLED may substantially emit electromagnetic radiation having wavelengths that vary by no more than about 30 nanometers, typically no more than about 20 nanometers (e.g., a UVLED emitting a narrow band of UV radiation mostly between about 375 nanometers and 395 nanometers). It has been observed that a UVLED emitting a narrow band of UV radiation mostly between about 395 nanometers and 415 nanometers is more efficient than other narrow bands of UV radiation. Moreover, it has been observed that UVLEDs emitting UV radiation slightly above the wavelength at which a glass-fiber coating has maximum absorption (e.g., about 360 nanometers) promote more efficient polymerization than do UVLEDs emitting UV radiation at the wavelength at which the glass-fiber coating has maximum absorption. In this regard, although an exemplary UVLED emits substantially all of its electromagnetic radiation within a defined range (e.g., between 350 nanometers and 450 nanometers, such as between 370 nanometers and 400 nanometers), the UVLED may emit small amounts of electromagnetic radiation outside the defined range. In this regard, 80 percent or more (e.g., at least about 90 percent) of the output (i.e., emitted electromagnetic radiation) of an exemplary UVLED is typically within a defined range (e.g., between about 375 nanometers and 425 nanometers). UVLEDs are typically much smaller than conventional UV lamps (e.g., mercury bulbs). By way of example, the UVLED may be a 0.25-inch square UVLED. The UVLED may be affixed to a platform (e.g., a 1-inch square or larger mounting plate). Of course, other UVLED shapes and sizes are within the scope of the present invention. By way of example, a 3-millimeter square UVLED may be employed. Each UVLED may have a power output of as much as 32 watts (e.g., a UVLED having a power input of about 160 watts and a power output of about 32 watts). That said, UVLEDs having outputs greater than 32 watts (e.g., 64 watts) may be employed as such technology becomes available. Using UVLEDs with higher power output may be useful for increasing the rate at which optical fiber coatings cure, thus promoting increased production line speeds. Relative to other UV radiation sources, UVLED devices typically generate a smaller amount of heat energy. That said, to dissipate the heat energy created by a UVLED, a heat sink may be located behind the UVLED (e.g., opposite the portion of the UVLED that emits UV radiation). The heat sink may be one-inch square, although other heat sink shapes and sizes are within the scope of the present invention. The heat sink may be formed of a material suitable for conducting heat (e.g., brass, aluminum, or copper). The heat sink may include a heat exchanger that employs a liquid coolant (e.g., chilled water), which circulates within the heat exchanger to draw heat from the UVLED. Removing heat generated by the UVLED is important for several reasons. First, excess heat may slow the rate at which optical-fiber coatings cure. Furthermore, excess heat can cause the temperature of the UVLED to rise, which can reduce UV-radiation output. Indeed, continuous high-temperature exposure can permanently reduce the UVLED's radiation output. With adequate heat removal, however, the UVLED may have a useful life of 50,000 hours or more. In another exemplary embodiment, the apparatus for curing glass-fiber coatings includes two or more UVLEDs. For instance, the UVLEDs may be arranged in an array (e.g., a planar or non-planar array, such as a three-dimensional array). With respect to a three-dimensional array, two or more UVLEDs may be configured in two or more distinct planes that are substantially perpendicular to the central axis. As depicted in FIGS. 1 and 2, the UVLEDs 11, which emit UV radiation toward the curing space 15, are typically arranged approximately equidistant from the central axis 14. The UVLEDs, for instance, may be arranged to define one or more helixes (i.e., a helical array of UVLEDs). In an array containing more than one helix, the helixes may have the same chirality (i.e., asymmetric handedness). Alternatively, at least one helix may have the opposite chirality (e.g., one helix may be right-handed and a second helix may be left-handed). The three-dimensional array of UVLEDs may define a curing space that is suitable for the passage of a coated glass fiber for curing. As before, the curing space defines a central axis (e.g., the axis along which a drawn glass fiber passes during the curing process). The apparatus employing a three-dimensional array of UVLEDs for curing glass-fiber coatings may also include one or more mirrors for reflecting UV radiation into the curing space. For example, the apparatus may include a plurality of the foregoing UVLED-mirror pairs. By way of further example and as depicted in FIG. 4, a plurality of UVLEDs 11 may be embedded in a mirror 46 (e.g., a mirror in the shape of a circular, elliptical, or parabolic cylinder), the interior of which defines the curing space 15. It will be appreciated by those of skill in the art that the position of the UVLEDs in a three-dimensional array may be defined by the cylindrical coordinate system (i.e., r, θ, z). Using the cylindrical coordinate system and as described herein, the central axis of the curing space defines a z-axis. Furthermore, as herein described and as will be understood by those of ordinary skill in the art, the variable r is the perpendicular distance of a point to the z-axis (i.e., the central axis of the curing space). The variable θ describes the angle in a plane that is perpendicular to the z-axis. In other words and by reference to a Cartesian coordinate system (i.e., defining an x-axis, a y-axis, and a z-axis), the variable θ describes the angle between a reference axis (e.g., the x-axis) and the orthogonal projection of a point onto the x-y plane. Finally, the z variable describes the height or position of a reference point along the z-axis. Thus, a point is defined by its cylindrical coordinates (r, θ, z). For UVLEDs employed in exemplary configurations, the variable r is usually constant. Stated otherwise, the UVLEDs may be positioned approximately equidistant from the central axis (i.e., the z axis). Accordingly, to the extent the variable r is largely fixed, the position of the UVLEDs can be described by the z and θ coordinates. By way of example, a helical UVLED array may have a first UVLED at the position (1, 0, 0), where r is fixed at a constant distance (i.e., represented here as a unitless 1). Additional UVLEDs may be positioned, for example, every 90° (i.e., π/2) with a Δz of 1 (i.e., a positional step change represented here as a unitless 1). Thus, a second UVLED would have the coordinates (1, π/2, 1), a third UVLED would have the coordinates (1, π, 2), and a fourth UVLED would have the coordinates (1, 3π/2, 3), thereby defining a helical configuration. Those having ordinary skill in the art will appreciate that, as used in the foregoing example, the respective distances r and z need not be equivalent. Moreover, those having ordinary skill in the art will further appreciate that several UVLEDs in an array as herein disclosed need not be offset by 90° (e.g., π/2, π, 3π/2, etc.). For example, the UVLEDs may be offset by 60° (e.g., π/3, 2π/3, π, etc.) or by 120° (e.g., 2π/3, 4π/3, 2π, etc.). Indeed, the UVLEDs in an array as discussed herein need not follow a regularized helical rotation. It will be further appreciated by those of ordinary skill in the art that UVLEDs may absorb incident electromagnetic radiation, which might diminish the quantity of reflected UV radiation available for absorption by the glass-fiber coating. See FIG. 1. Therefore, in an apparatus for curing glass-fiber coatings having a plurality of UVLEDs, it may be desirable to position the UVLEDs in a way that reduces UV radiation incident to the UVLEDs. See FIGS. 2, 3, and 4. In an exemplary embodiment described using the cylindrical coordinate system, UVLEDs with a Δθ0 of π (i.e., UVLEDs positioned on opposite sides of a UVLED array) may be positioned so that they have a Δz that is at least the height of the UVLED. Thus, if each UVLED has a height of 0.5 inch, a UVLED with a Δθ of π should have a Δz of at least 0.5 inch. It is thought that this would reduce the absorption by one UVLED of UV radiation emitted by another UVLED, thereby increasing the availability of UV radiation for reflection by one or more mirrors and absorption by the glass-fiber coating. Alternatively (or in accordance with the foregoing discussion), the UVLEDs may employ a reflective surface (e.g., a surface coating) that promotes reflection of incident electromagnetic radiation yet permits the transmission of emitted electromagnetic radiation. In view of the foregoing, yet another exemplary embodiment employs a plurality of UVLED-mirror pairs that are arranged in a three dimensional configuration. In particular, the plurality of UVLED-mirror pairs share a common curing space defining a common central axis. In an exemplary configuration, the UVLED-mirror pairs may be helically arranged (e.g., configured in a 60°, 90°, or 120° helical array). In yet another exemplary embodiment, the apparatus for curing glass-fiber coatings includes one or more UVLEDs positioned within a cylindrical cavity (or a substantially cylindrical cavity) having a reflective inner surface (e.g., made from stainless steel or silvered quartz, or otherwise including a reflective inner surface). The interior of the cylindrical cavity defines the curing space. As before, the curing space defines a curing axis (e.g., a central axis) along which a drawn glass fiber passes during the curing process. Moreover, one or more UVLEDs may be positioned within the cylindrical cavity such that they emit UV radiation in the direction of the curing axis. In a typical embodiment, the cylindrical cavity has a non-circular elliptical cross-section. In other words, the cylindrical cavity typically has the shape of an elliptic cylinder. For an elliptic cylinder the curing axis may correspond with one of the two line foci defined by the elliptic cylinder. In addition, each UVLED may be positioned along the other line focus such that they emit UV radiation in the general direction of the curing axis. This arrangement is useful for improving curing efficiency, because any electromagnetic radiation that is emitted from one line focus (regardless of direction) will be directed toward the other line focus after being reflected at the inner surface of the cylinder. This principle is illustrated in FIG. 7, which depicts a cross-section of a reflective elliptic cylinder 55 having a first line focus 51 and a second line focus 52. As depicted in FIG. 7, each UV ray 53 emitted from the first line focus 51 will intersect the second line focus 52. That said, the UV radiation emitted from a UVLED is not emitted from a single point. Therefore and because of the small size of a coated glass fiber, it is desirable to use small UVLEDs (e.g., a 3-millimeter square UVLED or a 1-millimeter square UVLED), because a greater percentage of emitted and reflected light from a small UVLED will be incident to the coated glass fiber. In accordance with the foregoing, FIGS. 8-9 depict an exemplary apparatus 60 for curing a coated glass fiber 66. The apparatus 60 includes a substantially cylindrical cavity 65 having an elliptical shape and having a reflective inner surface. The cavity 65 defines a first line focus 61 and a second line focus 62. A plurality of UVLEDs 64 are positioned along the first line focus 61. The second line focus 62 further defines a curing axis along which a coated glass fiber 66 passes so it can be cured. As depicted in FIG. 9, UV rays 63 emitted from the UVLEDs 64 may reflect off the inner surface of the cavity 65 such that the reflected UV rays 63 are incident to the coated glass fiber 66. To facilitate uniform curing of the coated glass fiber 66, some of the UVLEDs 64 may be differently oriented. For example, a second apparatus 70 for curing a glass fiber could have a different orientation than the apparatus 60 (e.g., the second apparatus 70 may have UVLEDs positioned along a line focus 71 that differs from the first line focus 61). In an alternative exemplary embodiment, rather than placing the UVLEDs along one of the line foci, each UVLED may include a lens for focusing emitted UV radiation. In particular, each lens may have a focus at one of the two line foci (e.g., the line focus not defining a curing axis). By including a lens with each UVLED, the efficiency of the apparatus can be further improved. An apparatus as described herein may include a dark space between one or more UVLEDs. In other words, the apparatus may include a space in which substantially no UV radiation is incident to the optical fiber being cured. A pause in the curing process provided by a dark space can help to ensure even and efficient curing of the optical fiber coatings. In particular, a dark space may be useful in preventing too many free radicals from being present in a glass-fiber coating before it is cured (i.e., dark space helps to control free-radical generation). For example, it may be desirable to initially expose an optical fiber to low power UV radiation and then pass the optical fiber through a dark space. After the optical fiber passes through a dark space, it is exposed to higher power UV radiation to complete the curing process. A curing apparatus employing dark space is disclosed in commonly assigned U.S. Pat. No. 7,322,122 for a Method and Apparatus for Curing a Fiber Having at Least Two Fiber Coating Curing Stages, which is hereby incorporated by reference in its entirety. An apparatus for curing glass-fiber coatings may include a control circuit for controlling the UV radiation output from the UVLED. The control circuit may be used to vary the intensity of the UV radiation as an optical fiber progresses through the apparatus. For example, to ensure that the optical fiber receives a consistent dose of ultraviolet radiation, the UV radiation output of the UVLEDs may vary with the speed at which the optical fiber passes through the apparatus. That is to say, at higher speeds (i.e., the speed the optical fiber passes through the apparatus) the output intensity of the UVLEDs may be greater than the output intensity at lower speeds. The output intensity of the UVLEDs may be controlled by reducing (or increasing) the current flowing to the UVLEDs. In another aspect, the present invention embraces a method of employing the foregoing apparatus to cure a coating on a glass fiber (i.e., in situ curing). In an exemplary method, a glass fiber is drawn from an optical preform and coated with a UV curable material. UV radiation is emitted from one or more sources of electromagnetic radiation (e.g., one or more UVLEDs) toward a curing space (e.g., in the general direction of the coated glass fiber). A portion, if not most, of the emitted UV radiation is transmitted entirely through the curing space. Typically, at least some, if not most, of the UV radiation transmitted entirely through the curing space (i.e., at least some UV radiation that has not been absorbed) is reflected (e.g., with a mirror) toward the curing space. A glass fiber having an incompletely cured coating is continuously passed through the curing space to effect the absorption of emitted and reflected UV radiation. The absorption of the UV radiation cures the glass-fiber coating. Moreover, and in accordance with the foregoing, to improve the curing rate, at least a portion of the reflected UV radiation may be focused on the glass fiber (e.g., by using a concave mirror to reflect UV radiation toward the curing space's curing axis). In accordance with the foregoing, the resulting optical fiber includes one or more coating layers (e.g., a primary coating and a secondary coating). At least one of the coating layers—typically the secondary coating—may be colored and/or possess other markings to help identify individual fibers. Alternatively, a tertiary ink layer may surround the primary and secondary coatings. For example, the resulting optical fiber may have one or more coatings (e.g., the primary coating) that comprise a UV-curable, urethane acrylate composition. In this regard, the primary coating may include between about 40 and 80 weight percent of polyether-urethane acrylate oligomer as well as photoinitiator, such as LUCIRIN® TPO, which is commercially available from BASF. In addition, the primary coating typically includes one or more oligomers and one or more monomer diluents (e.g., isobornyl acrylate), which may be included, for instance, to reduce viscosity and thereby promote processing. Exemplary compositions for the primary coating include UV-curable urethane acrylate products provided by DSM Desotech (Elgin, Ill.) under various trade names, such as DeSolite® DP 1011, DeSolite® DP 1014, DeSolite® DP 1014XS, and DeSolite® DP 1016. Those having ordinary skill in the art will recognize that an optical fiber with a primary coating (and an optional secondary coating and/or ink layer) typically has an outer diameter of between about 235 microns and about 265 microns (μm). The component glass fiber itself (i.e., the glass core and surrounding cladding layers) typically has a diameter of about 125 microns, such that the total coating thickness is typically between about 55 microns and 70 microns. With respect to an exemplary optical fiber achieved according to the present curing method, the component glass fiber may have an outer diameter of about 125 microns. With respect to the optical fiber's surrounding coating layers, the primary coating may have an outer diameter of between about 175 microns and about 195 microns (i.e., a primary coating thickness of between about 25 microns and 35 microns) and the secondary coating may have an outer diameter of between about 235 microns and about 265 microns (i.e., a secondary coating thickness of between about 20 microns and 45 microns). Optionally, the optical fiber may include an outermost ink layer, which is typically between two and ten microns thick. In an alternative embodiment, the resulting optical fiber may possess a reduced diameter (e.g., an outermost diameter between about 150 microns and 230 microns). In this alternative optical fiber configuration, the thickness of the primary coating and/or secondary coating is reduced, while the diameter of the component glass fiber is maintained at about 125 microns. By way of example, in such embodiments the primary coating layer may have an outer diameter of between about 135 microns and about 175 microns (e.g., about 160 microns), and the secondary coating layer may have an outer diameter of between about 150 microns and about 230 microns (e.g., more than about 165 microns, such as 190-210 microns or so). In other words, the total diameter of the optical fiber is reduced to less than about 230 microns (e.g., about 200 microns). Exemplary coating formulations for use with the apparatus and method described herein are disclosed in the following commonly assigned applications, each of which is incorporated by reference in its entirety: U.S. Patent Application No. 61/112,595 for a Microbend-Resistant Optical Fiber, filed Nov. 7, 2008, (Overton); International Patent Application Publication No. WO 2009/062131 A1 for a Microbend-Resistant Optical Fiber, (Overton); U.S. Patent Application Publication No. US2009/0175583 A1 for a Microbend-Resistant Optical Fiber, (Overton); and U.S. patent application Ser. No. 12/614,011 for a Reduced-Diameter Optical Fiber, filed Nov. 6, 2009, (Overton). To supplement the present disclosure, this application incorporates entirely by reference the following commonly assigned patents, patent application publications, and patent applications: U.S. Pat. No. 4,838,643 for a Single Mode Bend Insensitive Fiber for Use in Fiber Optic Guidance Applications (Hodges et al.); U.S. Pat. No. 7,623,747 for a Single Mode Optical Fiber (de Montmorillon et al.); U.S. Pat. No. 7,587,111 for a Single-Mode Optical Fiber (de Montmorillon et al.); U.S. Pat. No. 7,356,234 for a Chromatic Dispersion Compensating Fiber (de Montmorillon et al.); U.S. Pat. No. 7,483,613 for a Chromatic Dispersion Compensating Fiber (de Montmorillon et al.); U.S. Pat. No. 7,555,186 for an Optical Fiber (Flammer et al.); U.S. Patent Application Publication No. US2009/0252469 A1 for a Dispersion-Shifted Optical Fiber (Sillard et al.); U.S. patent application Ser. No. 12/098,804 for a Transmission Optical Fiber Having Large Effective Area (Sillard et al.), filed Apr. 7, 2008; U.S. Patent Application Publication No. US2009/0279835 A1 for a Single-Mode Optical Fiber Having Reduced Bending Losses, filed May 6, 2009, (de Montmorillon et al.); U.S. Patent Application Publication No. US2009/0279836 A1 for a Bend-Insensitive Single-Mode Optical Fiber, filed May 6, 2009, (de Montmorillon et al.); U.S. patent application Ser. No. 12/489,995 for a Wavelength Multiplexed Optical System with Multimode Optical Fibers, filed Jun. 23, 2009, (Lumineau et al.); U.S. patent application Ser. No. 12/498,439 for a Multimode Optical Fibers, filed Jul. 7, 2009, (Gholami et al.); U.S. patent application Ser. No. 12/614,172 for a Multimode Optical System, filed Nov. 6, 2009, (Gholami et al.); U.S. patent application Ser. No. 12/617,316 for an Amplifying Optical Fiber and Method of Manufacturing, filed Nov. 12, 2009, (Pastouret et al.) U.S. patent application Ser. No. 12/629,495 for an Amplifying Optical Fiber and Production Method, filed Dec. 2, 2009, (Pastouret et al.); U.S. patent application Ser. No. 12/633,229 for an Ionizing Radiation-Resistant Optical Fiber Amplifier, filed Dec. 8, 2009, (Regnier et al.); and U.S. patent application Ser. No. 12/636,277 for a Buffered Optical Fiber, filed Dec. 11, 2009, (Testu et al.). To supplement the present disclosure, this application further incorporates entirely by reference the following commonly assigned patents, patent application publications, and patent applications: U.S. Pat. No. 5,574,816 for Polypropylene-Polyethylene Copolymer Buffer Tubes for Optical Fiber Cables and Method for Making the Same; U.S. Pat. No. 5,717,805 for Stress Concentrations in an Optical Fiber Ribbon to Facilitate Separation of Ribbon Matrix Material; U.S. Pat. No. 5,761,362 for Polypropylene-Polyethylene Copolymer Buffer Tubes for Optical Fiber Cables and Method for Making the Same; U.S. Pat. No. 5,911,023 for Polyolefin Materials Suitable for Optical Fiber Cable Components; U.S. Pat. No. 5,982,968 for Stress Concentrations in an Optical Fiber Ribbon to Facilitate Separation of Ribbon Matrix Material; U.S. Pat. No. 6,035,087 for an Optical Unit for Fiber Optic Cables; U.S. Pat. No. 6,066,397 for Polypropylene Filler Rods for Optical Fiber Communications Cables; U.S. Pat. No. 6,175,677 for an Optical Fiber Multi-Ribbon and Method for Making the Same; U.S. Pat. No. 6,085,009 for Water Blocking Gels Compatible with Polyolefin Optical Fiber Cable Buffer Tubes and Cables Made Therewith; U.S. Pat. No. 6,215,931 for Flexible Thermoplastic Polyolefin Elastomers for Buffering Transmission Elements in a Telecommunications Cable; U.S. Pat. No. 6,134,363 for a Method for Accessing Optical Fibers in the Midspan Region of an Optical Fiber Cable; U.S. Pat. No. 6,381,390 for a Color-Coded Optical Fiber Ribbon and Die for Making the Same; U.S. Pat. No. 6,181,857 for a Method for Accessing Optical Fibers Contained in a Sheath; U.S. Pat. No. 6,314,224 for a Thick-Walled Cable Jacket with Non-Circular Cavity Cross Section; U.S. Pat. No. 6,334,016 for an Optical Fiber Ribbon Matrix Material Having Optimal Handling Characteristics; U.S. Pat. No. 6,321,012 for an Optical Fiber Having Water Swellable Material for Identifying Grouping of Fiber Groups; U.S. Pat. No. 6,321,014 for a Method for Manufacturing Optical Fiber Ribbon; U.S. Pat. No. 6,210,802 for Polypropylene Filler Rods for Optical Fiber Communications Cables; U.S. Pat. No. 6,493,491 for an Optical Drop Cable for Aerial Installation; U.S. Pat. No. 7,346,244 for a Coated Central Strength Member for Fiber Optic Cables with Reduced Shrinkage; U.S. Pat. No. 6,658,184 for a Protective Skin for Optical Fibers; U.S. Pat. No. 6,603,908 for a Buffer Tube that Results in Easy Access to and Low Attenuation of Fibers Disposed Within Buffer Tube; U.S. Pat. No. 7,045,010 for an Applicator for High-Speed Gel Buffering of Flextube Optical Fiber Bundles; U.S. Pat. No. 6,749,446 for an Optical Fiber Cable with Cushion Members Protecting Optical Fiber Ribbon Stack; U.S. Pat. No. 6,922,515 for a Method and Apparatus to Reduce Variation of Excess Fiber Length in Buffer Tubes of Fiber Optic Cables; U.S. Pat. No. 6,618,538 for a Method and Apparatus to Reduce Variation of Excess Fiber Length in Buffer Tubes of Fiber Optic Cables; U.S. Pat. No. 7,322,122 for a Method and Apparatus for Curing a Fiber Having at Least Two Fiber Coating Curing Stages; U.S. Pat. No. 6,912,347 for an Optimized Fiber Optic Cable Suitable for Microduct Blown Installation; U.S. Pat. No. 6,941,049 for a Fiber Optic Cable Having No Rigid Strength Members and a Reduced Coefficient of Thermal Expansion; U.S. Pat. No. 7,162,128 for Use of Buffer Tube Coupling Coil to Prevent Fiber Retraction; U.S. Pat. No. 7,515,795 for a Water-Swellable Tape, Adhesive-Backed for Coupling When Used Inside a Buffer Tube (Overton et al.); U.S. Patent Application Publication No. 2008/0292262 for a Grease-Free Buffer Optical Fiber Buffer Tube Construction Utilizing a Water-Swellable, Texturized Yarn (Overton et al.); European Patent Application Publication No. 1,921,478 A1, for a Telecommunication Optical Fiber Cable (Tatat et al.); U.S. Pat. No. 7,570,852 for an Optical Fiber Cable Suited for Blown Installation or Pushing Installation in Microducts of Small Diameter (Nothofer et al.); U.S. Patent Application Publication No. US 2008/0037942 A1 for an Optical Fiber Telecommunications Cable (Tatat); U.S. Pat. No. 7,599,589 for a Gel-Free Buffer Tube with Adhesively Coupled Optical Element (Overton et al.); U.S. Pat. No. 7,567,739 for a Fiber Optic Cable Having a Water-Swellable Element (Overton); U.S. Patent Application Publication No. US2009/0041414 A1 for a Method for Accessing Optical Fibers within a Telecommunication Cable (Lavenne et al.); U.S. Patent Application Publication No. US2009/0003781 A1 for an Optical Fiber Cable Having a Deformable Coupling Element (Parris et al.); U.S. Patent Application Publication No. US2009/0003779 A1 for an Optical Fiber Cable Having Raised Coupling Supports (Parris); U.S. Patent Application Publication No. US2009/0003785 A1 for a Coupling Composition for Optical Fiber Cables (Parris et al.); U.S. Patent Application Publication No. US2009/0214167 A1 for a Buffer Tube with Hollow Channels, (Lookadoo et al.); U.S. patent application Ser. No. 12/466,965 for an Optical Fiber Telecommunication Cable, filed May 15, 2009, (Tatat); U.S. patent application Ser. No. 12/506,533 for a Buffer Tube with Adhesively Coupled Optical Fibers and/or Water-Swellable Element, filed Jul. 21, 2009, (Overton et al.); U.S. patent application Ser. No. 12/557,055 for an Optical Fiber Cable Assembly, filed Sep. 10, 2009, (Barker et al.); U.S. patent application Ser. No. 12/557,086 for a High-Fiber-Density Optical Fiber Cable, filed Sep. 10, 2009, (Louie et al.); U.S. patent application Ser. No. 12/558,390 for a Buffer Tubes for Mid-Span Storage, filed Sep. 11, 2009, (Barker); U.S. patent application Ser. No. 12/614,692 for Single-Fiber Drop Cables for MDU Deployments, filed Nov. 9, 2009, (Overton); U.S. patent application Ser. No. 12/614,754 for Optical-Fiber Loose Tube Cables, filed Nov. 9, 2009, (Overton); U.S. patent application Ser. No. 12/615,003 for a Reduced-Size Flat Drop Cable, filed Nov. 9, 2009, (Overton et al.); U.S. patent application Ser. No. 12/615,106 for ADSS Cables with High-Performance Optical Fiber, filed Nov. 9, 2009, (Overton); U.S. patent application Ser. No. 12/615,698 for Reduced-Diameter Ribbon Cables with High-Performance Optical Fiber, filed Nov. 10, 2009, (Overton); U.S. patent application Ser. No. 12/615,737 for a Reduced-Diameter, Easy-Access Loose Tube Cable, filed Nov. 10, 2009, (Overton); U.S. patent application Ser. No. 12/642,784 for a Method and Device for Manufacturing an Optical Preform, filed Dec. 19, 2009, (Milicevic et al.); and U.S. patent application Ser. No. 12/648,794 for a Perforated Water-Blocking Element, filed Dec. 29, 2009, (Parris). In the specification and/or figures, typical embodiments of the invention have been disclosed. The present invention is not limited to such exemplary embodiments. The figures are schematic representations and so are not necessarily drawn to scale. Unless otherwise noted, specific terms have been used in a generic and descriptive sense and not for purposes of limitation.
	summary
	claims	1. A carrying bag for transporting a radioactive source comprising: at least one flexible panel comprising: an outer layer; a lining formed from a radiation shielding material, the at least one panel being joined together adjacent edges thereof to define an interior space with an upper open end for receiving the radioactive source therein; and at least one carrying handle. 2. The carrying bag of claim 1 , wherein the radioactive source comprises a flood source. claim 1 3. The carrying bag of claim 1 , wherein the bag has a weight of less than 12 kg. claim 1 4. The carrying bag of claim 3 , wherein the bag has a weight of less than 10 kg. claim 3 5. The carrying bag of claim 1 , wherein the radiation shielding material includes a High-Z material selected from the group consisting of lead, tungsten, gold, bismuth, copper, cobalt, tantalum, nickel, silver and alloys, compounds and combinations thereof. claim 1 6. The carrying bag of claim 5 , wherein the radiation shielding material includes tungsten, lead, or a combination thereof. claim 5 7. The carrying bag of claim 1 , wherein the radiation shielding material is a composite material including: claim 1 a binder; a High Z material distributed throughout the binder; and optionally, fibers distributed throughout the binder. 8. The carrying bag of claim 7 , wherein the High Z material includes tungsten or lead at between about 5% and about 95% of the composite material by weight. claim 7 9. The carrying bag of claim 7 , wherein the binder includes a polymer selected from the group consisting of polyvinyls, polyurethane prepolymers, celluloses, fluoropolymers, ethylene inter-polymer alloy elastomers, acetates, such as ethylene vinyl acetate, nylon, polyether imides, polyester elastomers, polyester sulfones, polyphenyl amides, polypropylene, polyvinylidene fluorides or thermoset polyurea elastomers, acrylics, homopolymers, acrylonitrile-butadiene-styrene copolymers, thermoplastic fluoro polymers, ionomers, polyamides, polyamide-imides, polyacrylates, polyaryl-sulfones, polybenzimidazoles, polycarbonates, polybutylene terephthalates, polyether imides, polyether sulfones, thermoplastic polyimides, thermoplastic polyurethanes, polyphenylene sulfides, polyethylene, polysulfones, polyvinylchlorides, styrene acrylonitriles, polystyrenes, polyphenylene ether blends, styrene maleic anhydrides, polycarbonates, cyanates, epoxies, phenolics, unsaturated polyesters, bismaleimides, polyurethanes, silicones, vinylesters, urethane hybrids, and combinations thereof. claim 7 10. The carrying bag of claim 7 , wherein the binder comprises between about 2% to about 20% of the composite material by weight. claim 7 11. The carrying bag of claim 7 , wherein the fibers are selected from the group consisting of stainless steel, copper, nickel, niobium, nickel, titanium, nylon, Kevlar(trademark), Spectra(trademark), glass, boron, or carbon, or combinations thereof. claim 7 12. The carrying bag of claim 1 , wherein the radiation shielding material shields at least about 50% of the emission from the radiation source. claim 1 13. The carrying bag of claim 1 , wherein the outer layer is formed from fabric. claim 1 14. The carrying bag of claim 1 , further including an inner layer, the outer layer and the inner layers enclosing the lining. claim 1 15. The carrying bag of claim 1 , further including: claim 1 a closure member for releasably closing the opening. 16. The carrying bag of claim 15 , further including an upper panel connected with a rear panel member, the closure member comprising a hook and loop closure for selectively connecting the upper panel member to a front panel member. claim 15 17. The carrying bag of claim 1 , wherein the bag has no rotatable members for wheeling the bag across a floor. claim 1 18. The carrying bag of claim 1 , further including: claim 1 a stiffening layer which allows at least a portion of the bag to hold its shape while a flood source is inserted. 19. A method of transporting a radioactive source comprising: placing the radioactive source in the bag of claim 1 ; and claim 1 transporting the bag by grasping the handle with the hand. 20. The method of claim 19 , wherein the step of transporting includes lifting the bag off the floor. claim 19 21. A carrying bag for transporting a flood source comprising: a front panel member; a rear panel member, the front and rear panel members being joined along base and side edges to define an interior space with an upper open end for receiving the radioactive source therein, the front and rear panel members each comprising: an outer layer, an inner layer, and a lining formed from a radiation shielding material between the inner and outer layers; an upper panel member shaped to cover the opening when the flood source is positioned within the interior space, the upper panel being connected with the rear panel member; and a closure member for selectively fastening the upper panel to the front panel to close the opening. 22. The carrying bag of claim 21 , further comprising: claim 21 a first carrying member attached to the front panel member; and a second carrying member attached to the rear panel member. 23. The carrying bag of claim 21 , further comprising: claim 21 a stiffening layer which allows at least a portion of the bag to hold its shape while a flood source is inserted. 24. A method of forming a bag for shielding a flood source comprising: covering a sheet of a radiation shielding material with a sheet of fabric to form a radiation shielding panel; folding the radiation shielding panel to define a front panel member, a rear panel member and a top panel member; attaching the front panel member to the rear panel member along side edges thereof; and forming a closure member, a first portion of the closure member being associated with the top panel member, a second portion of the closure member being associated with the front panel member, the closure member being configured for selectively engaging the top panel member and front panel member. 25. The method of claim 24 , further comprising: claim 24 providing at least one of the front panel member and rear panel member with a carrying handle.
	abstract	An inspection robot for inspecting a nuclear reactor that includes a hull and an on-board control mechanism that controls the operation of the inspection robot. The on-board control mechanism controls one or more sensors used to inspect one or more structures in the nuclear reactor as well as the movement by the inspection robot. A gimbal mechanism rotates the inspection robot hull by shifting the center-of-mass so that gravity and buoyancy forces generate a moment to rotate the hull in a desired direction. A camera is coupled to the gimbal mechanism for providing visual display of the one or more structures in the nuclear reactor. The camera is allowed to rotate about an axis using the gimbal mechanism. The inspection robot communicates its findings with respect to the inspection tasks using the wireless communication link.
	description	The following relates to the nuclear power reactor arts, nuclear reaction control apparatus arts, control rod assembly arts, and related arts. In known nuclear power plants, a nuclear reactor core comprises a fissile material having size and composition selected to support a desired nuclear fission chain reaction. To moderate the reaction, a neutron absorbing medium may be provided, such as light water (H2O) in the case of light water reactors, or heavy water (D2O) in the case of heavy water reactors. It is further known to control or stop the reaction by inserting “control rods” comprising a neutron-absorbing material into aligned passages within the reactor core. When inserted, the control rods absorb neutrons so as to slow or stop the chain reaction. The control rods are operated by control rod drive mechanisms (CRDMs). In so-called “gray” control rods, the insertion of the control rods is continuously adjustable so as to provide continuously adjustable reaction rate control. In so-called “shutdown” control rods, the insertion is either fully in or fully out. During normal operation the shutdown rods are fully retracted from the reactor core; during a SCRAM, the shutdown rods are rapidly fully inserted so as to rapidly stop the chain reaction. Control rods can also be designed to perform both gray rod and shutdown rod functions. In some such dual function control rods, the control rod is configured to be detachable from the CRDM in the event of a SCRAM, such that the detached control rod falls into the reactor core under the influence of gravity. In some systems, such as naval systems, a hydraulic pressure or other positive force (other than gravity) is also provided to drive the detached control rod into the core. To complete the control system, a control rod/CRDM coupling is provided. A known coupling includes a connecting rod having a lower end at which the control rod is secured. The upper portion of the connecting rod operatively connects with the CRDM. A known CRDM providing gray rod functionality comprises a motor driving a lead screw that is integral with or rigidly connected with the connecting rod, such that operation of the motor can drive the lead screw and the integral or rigidly connected connecting rod up or down in a continuous fashion. A known CRDM providing shutdown functionality is configured to actively hold the control rod in the lifted position (that is, lifted out of the reactor core); in a SCRAM, the active lifting force is removed and the control rod and the integral or connected connecting rod fall together toward the reactor core (with the control rod actually entering into the reactor core). A known CRDM providing dual gray/shutdown functionality includes a motor/lead screw arrangement, and the connection between the motor and the lead screw is designed to release the lead screw during SCRAM. For example, the motor may be connected with the lead screw via a separable ball nut that is actively clamped to the lead screw during normal (gray) operation, and separates in the event of a SCRAM so that the control rod, the connecting rod, and the lead screw SCRAM together (that is, fall together toward the reactor core). Related application Ser. No. 12/722,662 titled “Control Rod Drive Mechanism For Nuclear Reactor” filed Mar. 12, 2010 and related application Ser. No. 12/722,696 titled “Control Rod Drive Mechanism For Nuclear Reactor” filed Mar. 12, 2010 are both incorporated herein by reference in their entireties. These applications disclose configurations in which the connection between the motor and the lead screw is not releasable, but rather a separate latch is provided between the lead screw and the connecting rod in order to effectuate SCRAM. In these alternative configurations the lead screw does not SCRAM, but rather only the unlatched connecting rod and control rod SCRAM together toward the reactor core while the lead screw remains engaged with the motor. The CRDM is a complex device, and is typically driven electrically and/or hydraulically. In the case of shutdown or dual gray/shutdown rods, the control rod system including the CRDM may also be classified as a safety related component—this status imposes strict reliability requirements on at least the shutdown functionality of the CRDM. To reduce cost and overall system complexity, it is known to couple a single CRDM with a plurality of control rods via an additional coupling element known as a “spider”. In such a case all the control rods coupled with a single CRDM unit move together. In practice a number of CRDM units are provided, each of which is coupled with a plurality of control rods, so as to provide some redundancy. The spider extends laterally away from the lower end of the connecting rod to provide a large “surface area” for attachment of multiple control rods. Although it is desired for the spider to have a large effective area, the spider also passes through the control rod support assembly. The support assembly guides the control rods as they are moved into or out of the reactor, so as to prevent control rod bowing or lateral movement of any control rod in any direction other than the desired “up/down” direction. The support assembly should cam against each control rod over a perimeter portion (transverse to the SCRAM direction) large enough to prevent rod bowing or lateral movement. Another limitation on the spider's effective area is that during a SCRAM the spider should not present a large hydraulic resistance that limits acceleration of the detached control rod/spider/connecting rod/(and, optionally, lead screw) assembly toward the reactor core during a SCRAM. Since the spider's “effective surface” for attachment of rods is oriented broadside to the SCRAM direction, this is a substantial concern. In view of these considerations, a spider typically comprises metal tubes or arms extending outward from a central attachment point at which the spider attaches with the connecting rod. In some spiders, additional supporting cross-members may be provided between the radially extending tubes, but the use of such cross-members is limited by the desire to minimize the actual area oriented broadside to the SCRAM direction. The diameters (or more generally, sizes) of the metal tubes or arms comprising the spider are kept as low as practicable in order to minimize hydraulic resistance of the spider during SCRAM and to enable the control rod support structure to contact and cam against all control rods during raising or lowering of the control rods. The spider is thus a lightweight, “spidery” structure having large lateral openings between the tubes or arms to reduce the actual surface area oriented broadside to the SCRAM direction. For various reasons such as strength and robustness, low cost, manufacturability, and compatibility with the reactor vessel environment, both the connecting rod and the spider are usually stainless steel elements. In one aspect of the disclosure, a control rod/control rod drive mechanism (CRDM) coupling comprises a connecting rod operatively connected with a CRDM unit to provide at least one of gray rod control functionality and shutdown rod control functionality, and a terminal element connected with a lower end of the connecting rod, the terminal element including a casing defining at least one cavity and a filler disposed in the at least one cavity. The filler comprises heavy material having a higher density than a material comprising the casing. The terminal element is further connected with an upper end of at least one control rod. In another aspect of the disclosure, a apparatus comprises a terminal element adapted to connect a lower end of a connecting rod with at least one control rod of a nuclear reactor. The terminal element has an average density that is greater than the density of stainless steel. In another aspect of the disclosure, a control rod/control rod drive mechanism (CRDM) coupling comprises a connecting rod operatively connected with a CRDM unit to provide at least one of gray rod control functionality and shutdown rod control functionality, and a terminal element connected with a lower end of the connecting rod. The terminal element has elongation in a SCRAM direction that is at least as large as a largest dimension of the terminal element transverse to the SCRAM direction. The terminal element is further connected with an upper end of at least one control rod. In another aspect of the disclosure, an apparatus comprises a nuclear reactor pressure vessel and a control rod assembly including at least one movable control rod comprising a neutron absorbing material, a control rod drive mechanism (CRDM) for controlling movement of the at least one control rod, and a coupling operatively connecting the at least one control rod and the CRDM. The coupling includes a connecting rod engaged with the CRDM and a terminal element connected with a lower end of the connecting rod. The terminal element includes a first portion comprising a first material having a first density and a second portion comprising a second material having a second density that is greater than the first density. The terminal element is further connected with the at least one control rod. In another aspect of the disclosure, an apparatus comprises a nuclear reactor pressure vessel and a control rod assembly including at least one movable control rod comprising a neutron absorbing material, a control rod drive mechanism (CRDM) for controlling movement of the at least one control rod, and a coupling operatively connecting the at least one control rod and the CRDM. The coupling includes a connecting rod engaged with the CRDM and a terminal element connected with a lower end of the connecting rod. The terminal element has a largest dimension parallel with the connecting rod that is greater than or equal to a largest dimension transverse to the connecting rod. Disclosed herein is a paradigm shift in control rod/CRDM coupling assemblies. In existing control rod/CRDM coupling assemblies, the control rod is terminated by a lightweight, “spidery” spider having a minimal weight and surface area oriented broadside to the SCRAM direction. The spider is configured to provide a large “effective” area for attachment of control rods, but a small “actual” area contributing to hydraulic resistance during SCRAM. Both the spider and the connecting rod are stainless steel components so as to provide benefits such as strength and robustness, low cost, manufacturability, and compatibility with the reactor vessel environment. Disclosed herein are control rod/CRDM coupling assemblies that include one or both of the following aspects: (i) replacement of the conventional lightweight spider with a terminal weighting element, and/or (ii) replacement of a substantial portion of the stainless steel of the control rod/CRDM coupling assembly with a denser material such as tungsten (optionally in a powdered or granulated form), molybdenum, tantalum, or so forth. The disclosed control rod/CRDM coupling assemblies are substantially heavier than conventional connecting rod/spider assemblies, which advantageously enhances the speed and reliability of gravitationally-induced SCRAM. In the case of control rod/CRDM coupling assemblies employing the disclosed terminal weighting element, the increased weight provided by the terminal weighting element as compared with a conventional lightweight spider enables the terminal weighting element to optionally have a larger actual surface area broadside to the SCRAM direction (for example, in order to provide the additional weight) as compared with the conventional spider. With reference to FIG. 1, a relevant portion of an illustrative nuclear reactor pressure vessel 10 includes a core former 12 located proximate to a bottom of the pressure vessel 10. The core former 12 includes or contains a reactive core (not shown) containing or including radioactive material such as, by way of illustrative example, enriched uranium oxide (that is, UO2 processed to have an elevated 235U/238U ratio). A control rod drive mechanism (CRDM) unit 14 is diagrammatically illustrated. The illustrative CRDM 14 is an internal CRDM that is disposed within the pressure vessel 10; alternatively, an external CRDM may be employed. FIG. 1 shows the single illustrated CRDM unit 14 as an illustrative example; however, more generally there are typically multiple CRDM units each coupled with a different plurality of control rods (although these additional CRDM units are not shown in FIG. 1, the pressure vessel 10 is drawn showing the space for such additional CRDM units). Below the CRDM unit 14 is a control rod guide frame 16, which in the perspective view of FIG. 1 blocks from view the control rod/CRDM coupling assembly (not shown in FIG. 1). Extending below the guide frame 16 are a plurality of control rods 18. FIG. 1 shows the control rods 18 in their fully inserted position in which the control rods 18 are maximally inserted into the core former 12. In the fully inserted position, the terminal weighting element (or, in alternative embodiments, the spider) is located at a lower location 20 within the control rod guide frame 16 (and, again, hence not visible in FIG. 1). In the illustrative embodiment of FIG. 1, the CRDM unit 14 and the control rod guide frame 16 are spaced apart by a standoff 22 comprising a hollow tube having opposite ends coupled with the CRDM unit 14 and the guide frame 16, respectively, and through which the connecting rod (not shown in FIG. 1) passes. FIG. 1 shows only a lower portion of the illustrative pressure vessel 10. In an operating nuclear reactor, an open upper end 24 of the illustration is connected with one or more upper pressure vessel portions that together with the illustrated lower portion of the pressure vessel 10 form an enclosed pressure volume containing the reactor core (indicated by the illustrated core former 12), the control rods 18, the guide frame 16, and the internal CRDM unit 14. In an alternative embodiment, the CRDM unit is external, located above the reactor pressure vessel. In such embodiments, the external CRDM is connected with the control rods by a control rod/CRDM coupling assembly in which the connecting rod extends through a portal in the upper portion of the pressure vessel. With reference to FIG. 2, the control assembly including the CRDM unit 14, the control rod guide frame 16, the intervening standoff 22, and the control rods 18 is illustrated isolated from the reactor pressure vessel. Again, the control rod/CRDM coupling assembly is hidden by the control rod guide frame 16 and the standoff 22 in the view of FIG. 2. With reference to FIG. 3, the control rod guide frame 16 and the standoff 22 is again illustrated, but with the CRDM unit removed so as to reveal an upper end of a connecting rod 30 extending upwardly above the standoff 22. If the CRDM unit has gray rod functionality, then this illustrated upper end of the connecting rod 30 engages with the CRDM unit to enable the CRDM unit to raise or lower the control rod 30 and, hence, the attached control rods 18 (not shown in FIG. 3). If the CRDM unit has shutdown rod functionality, then this illustrated upper end is detachable from the CRDM unit during SCRAM. In each of FIGS. 1-4, a SCRAM direction S is indicated, which is the downward direction of acceleration of the falling control rods in the event of a SCRAM. With reference to FIG. 4, the control rods 18 and the connecting rod 30 are shown without any of the occluding components (e.g., without the guide frame, standoff, or CRDM unit). In the view of FIG. 4 an illustrative terminal weighting element 32 is visible, which provides connection of the plurality of control rods 18 with the lower end of the connecting rod 30. It will be noticed that, unlike a conventional spider, the terminal weighting element 32 has substantial elongation along the SCRAM direction S. The illustrated terminal weighting element 32 has the advantage of providing enhanced weight which facilitates rapid SCRAM; however, it is also contemplated to replace the illustrated terminal weighting element 32 with a conventional “spidery” spider. With reference to FIGS. 5 and 6, a perspective view and a side-sectional perspective view, respectively, of the terminal weighting element 32 is shown. The terminal weighting element 32 includes a substantially hollow casing 40 having upper and lower ends that are sealed off by upper and lower casing cover plates 42, 44. Four upper casing cover plates 42 are illustrated in FIG. 5 and two of the upper casing cover plates 42 are shown in the side-sectional persective view of FIG. 6. The tilt of the perspective view of FIG. 5 occludes the lower cover plates from view, but two of the lower cover plates 44 are visible “on-edge” in the side-sectional view of FIG. 6. The illustrative terminal weighting element 32 includes four lower casing cover plates 44 arranged analogously to the four upper casing cover plates 42 illustrated in FIG. 5. Further visualization of the illustrative terminal weighting element 32 is provided by FIG. 7, which shows a top view of the hollow casing 40 with the cover plates omitted. As seen in FIG. 7, the hollow casing 40 is cylindrical having a cylinder axis parallel with the SCRAM direction S and a uniform cross-section transverse to the cylinder axis. That cross-section is complex, and defines a central passage 50 and four cavities 52 spaced radially at 90° intervals around the central passage 50. The cross-section of the hollow casing 40 also defines twenty-four small passages 54 (that is, small compared with the central passage 50), of which only some of the twenty-four small passages 54 are expressly labeled in FIG. 7. Comparison of FIG. 7 with FIGS. 5 and 6 show that the passages 50, 54 each pass completely through the casing 50 and are not covered by the upper or lower cover plates 42, 44. Considering first the twenty-four small passages 54, these provide structures for securing the plurality of control rods 18. In some embodiments, each of the twenty-four of the small passages 54 retain a control rod, such that the plurality of control rods 18 consists of precisely twenty-four control rods. In other embodiments, one or more of the twenty-four small passages 54 may be empty or may be used for another purpose, such as being used as a conduit for in-core instrumentation wiring, in which case the plurality of control rods 18 consists of fewer than twenty-four control rods. It is to be further appreciated that the terminal weighting element 32 is merely an illustrative example, and that the terminal weighting element may have other cross-sectional configurations that provide for different numbers of control rods, e.g. more or fewer than twenty-four. The four cavities 52 spaced radially at 90° intervals around the central passage 50 are next considered. The substantially hollow casing 40 and the upper and lower cover plates 42, 44 are suitably made of stainless steel, although other materials are also contemplated. The upper and lower cover plates 42, 44 seal the four cavities 52. As shown in the side-sectional view of FIG. 6, the four cavities 52 are filled with a filler 56 comprising a heavy material, where the term “heavy material” denotes a material that has a higher density than the stainless steel (or other material) that forms the hollow casing 40. For example, the filler 56 may comprise a heavy material such as tungsten (optionally in a powdered or granulated form), depleted uranium, molybdenum, or tantalum, by way of some illustrative examples. By way of illustrative example, stainless steel has a density of about 7.5-8.1 grams/cubic centimeter, while tungsten has a density of about 19.2 grams/cubic centimeter and tantalum has a density of about 16.6 grams per cubic centimeter. In some preferred embodiments, the heavy material comprising the filler 56 has a density that is at least twice the density of the material comprising the casing 40. In some preferred embodiments in which the casing 40 comprises stainless steel, the heavy material comprising the filler 56 preferably has a density that is at least 16.2 grams per cubic centimeter. (All quantitative densities specified herein are for room temperature.) In some embodiments, the filler 56 does not contribute to the structural strength or rigidity of the terminal weighting element 32. Accordingly, heavy material comprising the filler 56 can be selected without consideration of its mechanical properties. For the same reason, the filler 56 can be in the form of solid inserts sized and shaped to fit into the cavities 52, or the filler 56 can be a powder, granulation, or other constitution. The cover plates 42, 44 seal the cavities 52, and so it is also contemplated for the heavy material comprising the filler 56 to be a material that is not compatible with the primary coolant flowing in the pressure vessel 10. Alternatively, if the heavy material comprising the filler 56 is a material that is compatible with the primary coolant flowing in the pressure vessel 10, then it is contemplated to omit the upper cover plates 42, in which case the cavities 52 are not sealed. Indeed, if the filler 56 is a solid material securely held inside the cavities 52, then it is contemplated to omit both the upper cover plates 42 and the lower cover plates 44. With continuing reference to FIGS. 5-7 and with further reference to FIG. 8, the terminal weighting element 32 passes through the control rod guide frame 16 as the control rods 18 are raised or lowered by action of the CRDM unit 14. The cylindrical configuration with constant cross-section over the length of the terminal weighting element 32 along the SCRAM direction S simplifies this design aspect. Moreover, the control rod guide frame 16 should cam against each control rod 18 to provide the desired control rod guidance. Toward this end, the cross-section of the terminal weighting element 32 is designed with recesses 58 (some of which are labeled in FIG. 7). As shown in FIG. 8, into these recesses 58 fit mating extensions 60 of the control rod guide frame 16. A gap G also indicated in FIG. 8 provides a small tolerance between the outer surface of the terminal weighting element 32 and the proximate surface of the control rod guide frame 16. The twenty-four partial circular openings of the guide frame 16 which encompass the twenty-four small passages 54 of the terminal weighting element 32 are sized to cam against the control rods 18. For completeness, FIG. 8 also shows the connecting rod 30 disposed inside the central passage 50 of the terminal weighting element 32. FIGS. 5-7 show that providing space for the four cavities 52 substantially increases the actual cross-sectional area of the terminal weighting element 32 (that is, the area arranged broadside to the SCRAM direction S), as compared with the actual cross-sectional area that could be achieved without these four cavities 52. In some embodiments, the “fill factor” for the cross-section oriented broadside to the SCRAM direction S (including the area encompassed by the cover plates 42, 44) is at least 50%, and FIG. 7 demonstrates that the fill factor is substantially greater than 50% for the illustrative terminal weighting element. Thus, the design of the terminal weighting element 32 is distinct from the “spidery” design of a typical spider, which is optimized to minimize the actual surface area broadside to the SCRAM direction S and generally has a fill factor of substantially less than 50% in order to reduce hydraulic resistance. In general, the SCRAM force achieved by the weight of the terminal weighting element 32 more than offsets the increased hydraulic resistance of the greater actual broadside surface area imposed by the four cavities 52. Additional weight to overcome the hydraulic resistance and enhance SCRAM speed is obtained by elongating the terminal weighting element 32 in the SCRAM direction S. Said another way, a ratio of a length of the terminal weighting element 32 in the SCRAM direction S versus the largest dimension oriented broadside to the SCRAM direction S is optionally equal to or greater than one, and is more preferably equal to or greater than 1.2. The illustrative terminal weighting element 32 is not a generally planar element as per a typical spider, but rather is a volumetric component that provides substantial terminal weight to the lower end of the connecting rod 30. The illustrative terminal weighting element 32 has a substantial advantage in that it places the filler 56 comprising heavy material between the radioactive core (contained in or supported by the core former 12 located proximate to the bottom of the pressure vessel 10 as shown in FIG. 1) and the CRDM unit 14. The heavy material comprising the filler 56 is a dense material which can generally be expected to be highly absorbing for radiation generated by the reactor core. High radiation absorption is a property of heavy materials such as tungsten, depleted uranium, molybdenum, or tantalum, by way of illustrative example. Thus, the filler 56 comprising heavy material provides radiation shielding that protects the expensive and (in some embodiments and to various extent) radiation-sensitive CRDM unit 14. The elongation of the terminal weighting element 32 in the SCRAM direction S has additional benefits that are independent of providing weight. The elongation in the SCRAM direction S provides a longer length over which each control rod 18 can be secured to the terminal weighting element 32, and similarly provides a longer length over which the connecting rod 30 can be secured to the terminal weighting element 32. This provides a better mechanical coupling, and also provides enhanced stabilizing torque to prevent the control rods 18 from tilting. In general, the elongation of the terminal weighting element 32 in the SCRAM direction S provides a more rigid mechanical structure that reduces the likelihood of problematic (or even catastrophic) deformation of the connecting rod/terminal weighting element/control rods assembly. Another advantage of the elongation of the terminal weighting element 32 in the SCRAM direction S is that it optionally allows for streamlining the terminal weighting element 32 in the SCRAM direction S. This variation is not illustrated; however, it is contemplated to modify the configuration of FIG. 5 (by way of illustrative example) to have a narrower lower cross-section and a broader upper cross section, with a conical surface of increasing diameter running from the narrower lower cross-section to the broader upper cross section. The small passages 54 for securing the control rods would remain oriented precisely parallel with the SCRAM direction S (and, hence, would be shorter for control rods located at the outermost positions). Such streamlining represents a trade-off between hydraulic resistance (reduced by the streamlining) and weight reduction caused by the streamlining. Instead of the mentioned optional streamlining, the cross-section of the terminal weighting element can be otherwise configured to reduce hydraulic resistance. For example, the cross-section can include additional passages (not shown) analogous to the small passages 54, but which are not filled with control rods or anything else, and instead provide fluid flow paths to reduce the hydraulic resistance of the terminal weighting element during a SCRAM. The illustrative terminal weighting element 32 provides a desired weight by a combination of the filler 56 comprising a heavy material (which increases the average density of the terminal weighting element 32 to a value greater than the average density of stainless steel) and the elongation of the terminal weighting element 32 (which increases the total volume of the terminal weighting element 32). The total mass (equivalent to weight) is given by the product of the volume and the average density. To achieve a desired weight, various design trade-offs can be made amongst: (1) the size or amount or volume of the filler 56; (2) the density of the heavy material comprising the filler 56; and (3) the elongation of the terminal weighting element 32. In some embodiments, it is contemplated to achieve the desired weight by using a filler comprising a heavy material without elongating the terminal weighting element. In such embodiments, the terminal weighting element 32 may optionally have a conventional substantially planar and “spidery” spider configuration, in which the tubes or other connecting elements of the spider are partially or wholly hollow to define cavities containing the filler comprising a heavy material. Such a terminal weighting element can be thought of as a “heavy spider”. In other embodiments, it is contemplated to omit the filler material entirely, and instead to rely entirely upon elongation to provide the desired weight. For example, the illustrated terminal weighting element 32 can be modified by omitting the four cavities 52 and the filler 56. In this configuration the casing 40 can be replaced by a single solid stainless steel element having the same outer perimeter as the casing 40, with the top and bottom of the single solid stainless steel element defining (or perhaps better stated, replacing) the upper and lower casing cover plates 42, 44. Such embodiments omitting the filler comprising heavy material are suitably employed if the elongated terminal weighting element 32 made entirely of stainless steel provides sufficient weight. Such embodiments are also suitably employed if the weight of the terminal element is not a consideration, but other benefits of the elongated terminal element are desired, such as providing a longer length for secure connection with the control rods and/or the connecting rod 30, or providing an elongated geometry in the SCRAM direction S which is amenable to streamlining. Various embodiments of the disclosed terminal weighting elements use a stainless steel casing that does not compromise the primary function of providing a suitable structure for coupling the control rods to the lower end of the connecting rod. At the same time, the stainless steel casing leaves sufficient void or cavity volume to allow a filler comprising a heavy material to be inserted. Although stainless steel is referenced as a preferred material for the casing, it is to be understood that other materials having desired structural characteristics and reactor pressure vessel compatibility can also be used. The filler comprising heavy material is suitably tungsten, depleted uranium, or another suitably dense material. Various embodiments of the disclosed terminal weighting elements also have elongation in the SCRAM direction S. This elongated design is readily configured to fit into the control rod guide frame without any redesign (e.g., widening) of the guide frame, and hence does not impact the space envelope of the overall control rod assembly. The elongation is an adjustable design parameter, and can be set larger or smaller to provide the desired weight. Increasing the elongation generally increases the control rod assembly height, and this may impose an upper limit on the elongation for a particular reactor design. (This may be at least partially compensated by reducing the connecting rod length, but the connecting rod has a minimum length imposed by the desired maximum travel). Another advantage of the disclosed terminal weighting element is that it can provide adjustable weight. For example, in some embodiments different CRDM units may be located at different heights, or may support control rods of different masses, such that the different translating assemblies associated with the different CRDM units are not identical. If it is deemed beneficial for all translating assemblies associated with the various CRDM units to have the same weight, then different amounts of the filler comprising heavy material can be included in the cavities 52 of different terminal weighting elements 32 in order to equalize the weights of the translating assemblies. In some cases this might result in some cavities 52 being only partially filled with the filler 56. Optionally, the unfilled space of the cavities 52 can be filled with a light weight filler material such as a stainless steel slug (not shown) or can contain a compressed loading spring (not shown) to prevent the filler 56 comprising heavy material from moving about within the cavities 52. The weight of the light weight filler or loading spring is suitably taken into account in selecting the amount of filler 56 of heavy material to achieve a desired overall weight. Equalizing weights of the various translating assemblies can be useful, by way of example, to allow the use of a common plunger or other kinetic energy absorbing element in each translating assembly. The kinetic energy absorbing element (not shown) is designed to provide a “soft stop” to a translating assembly undergoing SCRAM when the control rods reach the point of full (i.e., maximal) insertion. The casing 40 of the illustrative terminal weighting element 32 acts as the structural part providing mechanical support. All loads associated with the coupling between the connecting rod 30 and the control rods 18 are transferred into the casing 40 which serves as the attachment location for each control rod. With reference to FIGS. 9, 10, and 11, various attachment configurations can be used for securing the connecting rod 30 in the attachment passage 50 of the casing 40 of the terminal weighting element 32. In an illustrative example of one such attachment configuration, the central passage 50 of the casing 40 houses a J-Lock female attachment assembly 70, which is suitably coaxially disposed inside the central passage 50 of the casing 40. FIG. 9 illustrates a side sectional view of the J-Lock female attachment assembly 70, while FIG. 10 shows a side view of the connected assembly and FIG. 11 shows a side sectional view of the connected assembly. With particular reference to FIG. 9, the illustrative J-Lock female attachment assembly 70 includes a hub 72 which in the illustrative embodiment comprises a round cylinder coaxially welded or otherwise secured in the central passage 50 of the casing 40. Alternatively, the hub may be integral with or defined by an inside surface of the central passage 50. The hub 72 serves as an interface between the casing 40 and the J-Lock female attachment components, which include three J-Lock pins 74 (two of which visible in the sectional view of FIG. 9) disposed inside of the hub 72. These pins 74 provide the connection points for a J-Lock male attachment assembly 80 (see FIG. 11) disposed at the lower end of the connecting rod 30. A J-Lock plunger 76 and a J-Lock spring 78 keeps the J-Lock male attachment assembly 80 of the connecting rod 30 in place once it has been engaged with the terminal weighting element 32. (Locked arrangement shown in FIG. 11). The illustrative J-Lock female attachment assembly 70 further includes a lower plunger 82, an inner spring 84, and a spring washer 86 which cooperate to absorb the impact of the lower translating assembly (that is, the translating combination of the control rods 18, the terminal weighting element 32, the connecting rod 30, and optionally a lead screw (not shown)) during a SCRAM. The illustrative J-Lock connection between the lower end of the connecting rod 30 and the terminal weighting element 32 is an example. More generally, substantially any type of connection, including another type of detachable connection or a permanently welded connection or an integral arrangement, is contemplated. The J-Lock arrangement has the advantage of enabling the connecting rod 30 to be detached from the terminal weighting element 32 (and, hence, from the control rods 18) by a simple “push-and-twist” operation. This allows the connecting rod 30 to be moved separately from the remainder of the translating assembly (that is, the terminal weighting element 32 and the attached control rods 18) during refueling of the nuclear reactor. The casing 40 of the terminal weighting element 32 can be manufactured using various techniques. In some embodiments manufacturing employing Electrical Discharge Machining (EDM) is contemplated. The EDM method operates on a solid block of stainless steel which is then cut to define the spider casing 40. Advantageously, EDM is fast and precise. Other contemplated methods include casting techniques or extrusion, both of which are fast and have low material cost. The translating assembly comprising the control rods 18, terminal weighting element 32, connecting rod 30, and optionally a lead screw (not illustrated) is advantageously heavy in order to facilitate rapid and reliable SCRAM of the translating assembly toward the reactor core in the event of an emergency reactor shutdown. Toward this end, the terminal weighting element 32 is configured to be heavy. One way disclosed herein to achieve this is by increasing the average density of the terminal weighting element 32 to a value greater than that of stainless steel (or, more generally, increasing its average density to a value greater than that of the material comprising the casing 40) by the addition of the filler 56 comprising heavy material (where “heavy” denotes a density greater than that of the stainless steel or other material comprising the casing 40). Another way disclosed herein to achieve this is by elongating the terminal weighting element 32 in the SCRAM direction S. The illustrative terminal weighting element 32 employs both enhanced average density via filler 56 and elongation in the SCRAM direction S. With reference to FIGS. 10 and 11, additional weight for the translating assembly is additionally or alternatively obtained by enhancing the density of the connecting rod 30. Toward this end, the illustrative connecting rod 30 includes a hollow (or partially hollow) connecting rod tube 90 which (as seen in the sectional view of FIG. 11) contains a filler 92 comprising heavy material. Thus, the connecting rod tube 90 serves the structural purpose analogous to the casing 40 of the terminal weighting element 32, while the filler 92 comprising heavy material serves a weighting (or average density-enhancing) purpose analogous to the filler 56 of the terminal weighting element 32. The hollow connecting rod tube 90 can be manufactured using various techniques, such as EDM (although longer tube lengths may be problematic for this approach), casting, extrusion, milling, or so forth. In one suitable embodiment, the filler 92 comprising heavy material is in the form of tungsten slugs each having a diameter substantially coinciding with an inner diameter of the connecting rod tube 90 and being stacked in the connecting rod tube 90, with the number of stacked tungsten slugs being selected to achieve the desired weight. If the number of tungsten slugs is insufficient to fill the interior volume of the connecting rod tube 90 and it is desired to avoid movement of these slugs, then optionally the filler 92 is prevented from shifting by a suitable biasing arrangement or by filling the remaining space within the interior volume of the connecting rod tube 90 with a light weight material such as stainless steel slugs. In the illustrative example of FIG. 11, a biasing arrangement is employed, in which the interior volume of the connecting rod tube 90 is sealed off by upper and lower welded plugs 94, 96, and a compressed spring 98 takes up any slack along the SCRAM direction S that may be introduced by incomplete filling of the interior volume of the connecting rod tube 90 by the filler 92. Instead of tungsten, the heavy material comprising the filler may be depleted uranium, molybdenum, tantalum, or so forth, by way of some other illustrative examples. The filler 92 may comprise one or more solid slugs or rods, a powder, a granulation, or so forth. In the context of the connecting rod 30, the term “heavy material” refers to a material having a density that is greater than the density of the stainless steel or other material comprising the connecting rod tube 90. By way of illustrative example, stainless steel has a density of about 7.5-8.1 grams/cubic centimeter, while tungsten has a density of about 19.2 grams/cubic centimeter and tantalum has a density of about 16.6 grams per cubic centimeter. In some preferred embodiments, the heavy material comprising the filler 92 has a density that is at least twice the density of the material comprising the hollow connecting rod tube 90. In some preferred embodiments in which the hollow connecting rod tube 90 comprises stainless steel, the heavy material comprising the filler 92 preferably has a density that is at least 16.2 grams per cubic centimeter. (All quantitative densities specified herein are for room temperature.) With continuing reference to FIGS. 10 and 11, the illustrative connecting rod 30 has an upper end that includes an annular groove 100 for securing with a latch of the CRDM unit 14 (latch not shown), and a magnet 102 for use in conjunction with a control rod position sensor (not shown). A suitable embodiment of the CRDM unit 14 including a motor/lead screw arrangement for continuous (gray rod) adjustment and a separate latch for detaching the connecting rod 30 from the CRDM unit 14 (with the lead screw remaining operatively connected with the motor) is described in related application Ser. No. 12/722,662 titled “Control Rod Drive Mechanism For Nuclear Reactor” filed Mar. 12, 2010 and related application Ser. No. 12/722,696 titled “Control Rod Drive Mechanism For Nuclear Reactor” filed Mar. 12, 2010, both of which are both incorporated herein by reference in their entireties. Alternatively, in other embodiments a lead screw (not shown) is secured with or integral with the connecting rod tube 90, and the lead screw SCRAMS together with the connecting rod/terminal weighting element (or spider)/control rod (in other words, the lead screw forms part of the translating assembly during SCRAM). In some such alternative embodiments, the motor is suitably coupled with the lead screw by a separable ball nut that separates to release the lead screw and initiate SCRAM. The illustrative connecting rod 30 includes eight components. The weight of the connecting rod 30 assembly is increased by using the hollow connecting rod tube 90. This may be only partially hollow—for example, only a lower portion may be hollow. Located inside the hollow connecting rod tube 90 is the filler 92 comprising heavy material. In some embodiments, the filler 92 comprises several smaller rods or slugs of tungsten. The number of tungsten rods or slugs inside the hollow connecting rod tube 90 is selected to achieve a desired weight. If different translating assemblies are employed with different CDRM units, the number of tungsten rods or slugs inside each the hollow connecting rod tube 90 may be different, and selected so as to ensure that each connecting rod of the several CDRM units has the same weight. This is advantageous since it follows that all of the CRDM units can be designed to lift a single weight independent of factors such as connecting rod length, control rod composition, or so forth. As already noted, such weight “tuning” can also be achieved by adjusting the filler 56 in the terminal weighting element 32. If both fillers 56, 92 are employed, then the combined weight of the fillers 56, 92 can be tuned by adjusting the amount and/or density of either one, or both, of the fillers 56, 92. If the amount of weight tuning is expected to be small, then in some such embodiments the fillers 56, 92 may be solid elements of standard size/weight, and the total weight may then be trimmed by adding additional filler comprising heavy material in the form of a powder, granulation, small slug or slugs, or so forth. If the interior volume of the hollow connecting rod tube 90 is only partially filled by the filler 92, then stainless steel rods or some other light weight filler (not shown) may be inserted into the remaining interior volume to fill complete the filling. Additionally or alternatively, the spring 98 or another mechanical biasing arrangement may be employed. It is contemplated to have the filler 92 arranged “loosely” in the rod tube 90; however, such an arrangement may complicate absorption of kinetic energy at the termination of a SCRAM drop. The filler 92 generally has a lower coefficient of thermal expansion than the stainless steel (or other material) of the hollow connecting rod tube 90. The connecting rod 30 is assembled at room temperature, and then heated to its operating temperature. For a connecting rod having a length of, e.g. 250 centimeters or greater, the thermal expansion will result in the rod tube 90 increasing by an amount of order a few centimeters or more. The lower coefficient of thermal expansion of the filler 92 results in a substantially lower length increase of the filler 92. The spring 98 suitably compensates for this effect. Additionally, if the spring 98 is located below the filler 92 (as shown in FIG. 11), then it can assist in dissipating the kinetic energy of the filler 92 at the termination of the SCRAM drop. As shown in the illustrative embodiment depicted in FIG. 11, the hollow connecting rod tube 90 may be less than the total length of the connecting rod 30. In the illustrated case, the connecting rod 30 includes additional length below the rod tube 90 corresponding to the J-Lock male attachment assembly 80, and also includes additional length above the rod tube 90 corresponding to an upper tube that includes the latch groove 100 and houses the position indicator magnet 102. The upper and lower welded plugs 94, 96 are optionally provided to seal off the interior volume of the hollow connecting rod tube 90. These plugs 94, 96 are attached to the upper and lower ends, respectively of the hollow connecting rod tube 90 so as to seal the filler 92 and the optional spring 98 inside. In the illustrative embodiment, the outer ends of the plugs 94, 96 are configured to facilitate connection of the upper connecting rod and the J-lock male attachment assembly 80, respectively. The connecting rod 30 also has a substantial advantage in that it places the filler 92 comprising heavy material between the radioactive core (contained in or supported by the core former 12 located proximate to the bottom of the pressure vessel 10 as shown in FIG. 1) and the CRDM unit 14. The heavy material comprising the filler 92 is a dense material which can generally be expected to be highly absorbing for radiation generated by the reactor core. High radiation absorption is a property of heavy materials such as tungsten, depleted uranium, molybdenum, or tantalum, by way of illustrative example. Thus, the filler 92 comprising heavy material provides radiation shielding that protects the expensive and (in some embodiments and to various extent) radiation-sensitive CRDM unit 14. If both fillers 56, 92 are used, then both fillers contribute to this advantageous CRDM shielding effect. The illustrative control rod/CRDM coupling includes a combination of (1) the terminal weighting element 32 including elongation and the filler 56, and (2) the connecting rod 30 including the filler 92. In other control rod/CRDM coupling embodiments it is contemplated to include a combination of the terminal weighting element 32 including elongation and the filler 56 but coupled with a conventional solid stainless steel connecting rod (without the filler 92). In other control rod/CRDM coupling embodiments it is contemplated to include a combination of a terminal element (which may or may not be a weighting element) including elongation but without the filler 56, coupled either with (i) the connecting rod 30 including the filler 92 or (ii) a conventional solid stainless steel connecting rod (without the filler 92). In other control rod/CRDM coupling embodiments it is contemplated to include a combination of a terminal weighting element without elongation (for example, having a “spidery” topology similar to a conventional spider) but which includes the filler 56 disposed in hollow regions of the tubes or other members of the terminal weighting element, coupled either with (i) the connecting rod 30 including the filler 92 or (ii) a conventional solid stainless steel connecting rod (without the filler 92). In other control rod/CRDM coupling embodiments it is contemplated to include a combination of (I) a conventional spider without elongation and without the filler 56 and (II) the connecting rod 30 including the filler 92. 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 system for preparing a container holding radioactive waste for dry storage. In one aspect, the invention can be a system for preparing a container having a cavity loaded with radioactive elements for dry storage, the system comprising: a gas circulation system comprising a condenser module, a desiccant module, and a gas circulator module; the gas circulation system configured to form a hermetically sealed closed-loop path when operably connected to the cavity of the container; and means for adding and removing the desiccant module as part of the hermetically sealed closed-loop path.
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053596390	summary	BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to computerized tomography (CT) for obtaining sectional images of an examinee by emitting X-rays from radial directions to the examinee, and particularly to a method and apparatus for obtaining a plurality of sectional images of an examinee lying still. 2. Description of the Related Art This type of CT apparatus includes an X-ray emitter and an X-ray detector opposed to each other across an examinee lying still on a top board. X-rays are emitted from radial directions to scan the examinee and collect projection data relating to X-ray absorption in the examinee's body. The data is reversely projected to reconstruct a distribution image of X-ray absorption coefficients in a sectional plane across the examinee's body, thereby to obtain a sectional image of the body. After one slice is scanned, the top board is slid to adjust a next slice of concern of the examinee to a direction of X-ray emission from the X-ray emitter, and a sectional image of this slice is obtained as above. If a sectional plane has an excessive slice thickness, a virtual image called a partial volume artifact tends to appear in a reconstructed image of, for example, the osseous basal region of brains. In practice, as disclosed in Japanese Patent Publication (Unexamined) No. 61-109551, data of numerous thin slice planes are collected and put to data processing such as addition to obtain a clear image of a thick sectional plane. However, such a method of obtaining a sectional image has the following disadvantage. The top board on which an examinee lies is slid at a relatively low speed (about 2 seconds) in order to avoid a displacement between a sectional plane of a site of concern and the X-ray emitter or the like. 0n the other hand, scanning by the X-ray emitter or the like is carried out at high speed (about 1 second). To collect data of numerous sectional planes under such conditions, sliding of the top board supporting the examinee and scanning by the X-ray emitter or the like must alternately be repeated numerous times. A long time is required to collect data of all of desired sectional planes particularly because of the slow sliding movement of the top board. SUMMARY OF THE INVENTION This invention has been made having regard to the state of the art noted above, and its object is, in relation to collection of data of numerous sectional planes with a CT apparatus, to provide a method and apparatus for reducing the time required to collect data of all of required sectional planes. The above object is fulfilled, according to one aspect of this invention, by a method of obtaining a sectional image of an examinee based on projection data relating to X-ray absorption in sectional planes of the examinee, which data are collected radially of the sectional planes by causing X-ray emitting means and X-ray detecting means opposed to each other across the examinee to scan the sectional planes of the examinee lying still, the method comprising the steps of: (a) scanning a predetermined number of sectional planes starting with a sectional plane in an initial position by successively shifting a direction of X-ray emission from the X-ray emitting means along a body axis of the examinee; PA1 (b) effecting a reset operation, after scanning the predetermined number of sectional planes, to switch the direction of X-ray emission to scan a sectional plane in the initial position, and moving the examinee synchronously with the reset operation to set a new sectional plane adjacent the predetermined number of sectional planes to the initial position; and PA1 (c) repeating the steps (a) and (b) above until all sectional planes are scanned. PA1 X-ray emitting direction switching means for shifting a direction of X-ray emission from the X-ray emitting means along a body axis of the examinee; PA1 examinee moving means for moving the examinee along the body axis; and PA1 control means for effecting a switching control by driving the X-ray emitting direction switching means to shift the direction of X-ray emission from the X-ray emitting means to scan one sectional plane and then a next sectional plane adjacent thereto, thereby to scan successively a predetermined number of sectional planes starting with a sectional plane in an initial position, a reset control by driving the X-ray emitting direction switching means, after scanning the predetermined number of sectional planes, to switch the direction of X-ray emission to scan a sectional plane in the initial position, and a further control by driving the examinee moving means to move the examinee synchronously with the reset control to set a new sectional plane adjacent the predetermined number of sectional planes to the initial position. A predetermined number of sectional planes are scanned, starting with a sectional plane in the initial position, by successively shifting the direction of X-ray emission from the X-ray emitting means along the body axis of the examinee. A reset operation is effected, after scanning the predetermined number of sectional planes, to switch the direction of X-ray emission to scan a sectional plane in the initial position. The examinee is moved synchronously with the reset operation to set a new sectional plane adjacent the predetermined number of sectional planes to the initial position. Subsequently, a predetermined number of sectional planes are scanned, starting with the new sectional plane in the initial position, by successively shifting the direction of X-ray emission from the X-ray emitting means along the body axis of the examinee. After scanning the predetermined number of sectional planes, a reset operation is effected and the examinee is moved to set a new sectional plane adjacent the predetermined number of sectional planes to the initial position as above. These operations are repeated until all sectional planes are scanned. That is, a predetermined number of sectional planes are successively scanned, starting with a sectional plane in the initial position, by shifting the direction of X-ray emission from the X-ray emitting means without moving the examinee. Consequently, the slow movement of the examinee does not occur during scanning of the predetermined number of sectional planes, thereby to achieve a substantial reduction in the time taken in collecting data of all sectional planes. With an increase in the number of sectional planes from which data are collected, the examinee moving time is correspondingly reduced to promote the reduction in processing time. In a further aspect of this invention, an apparatus for executing the above method is provided, which comprises: For scanning a predetermined number of sectional planes, starting with a sectional plane in the initial position, the control means drives the X-ray emitting direction switching means to shift successively the direction of X-ray emission from the X-ray emitting means along the body axis of the examinee. The control means effects a reset control, after scanning the predetermined number of sectional planes, to drive the X-ray emitting direction switching means to switch the direction of X-ray emission to scan a sectional plane in the initial position. The examinee moving means is driven synchronously with the reset control to move the examinee to set a new sectional plane adjacent the predetermined number of sectional planes to the initial position. Subsequently, the control means drives the X-ray emitting direction switching means to scan a predetermined number of sectional planes, starting with the new sectional plane in the initial position, by successively shifting the direction of X-ray emission from the X-ray emitting means along the body axis of the examinee. After scanning the predetermined number of sectional planes, the control means effects a reset control and moves the examinee to set a new sectional plane adjacent the predetermined number of sectional planes to the initial position as above. These operations are repeated until all sectional planes are scanned. That is, a predetermined number of sectional planes are successively scanned, starting with a sectional plane in the initial position, by driving the X-ray emitting direction switching means which is relatively fast, without moving the examinee which is relatively slow. This achieves a substantial reduction in the time taken in collecting data of all sectional planes. With an increase in the number of sectional planes from which data are collected, the examinee moving time is correspondingly reduced to promote the reduction in processing time.
	description	This invention relates to a container device for the long-term storage of hazardous materials. In particular, the type of hazardous material contemplated is nuclear fuel or other radioactive materials that retain a high activity level for very long times and have to be stored in a safe manner at least until the activity has fallen to a level which is not dangerous. For that reason, the invention will be described with particular reference to its application to the ultimate disposal of spent nuclear fuel. However, the applicability of the invention is not limited to any particular type of hazardous material. Other types of hazardous material that may be contemplated are nuclear weapons or parts of such weapons, war gases, extremely hazardous biological materials, etc. Container devices for the ultimate disposal of nuclear fuel have to meet requirements which are much more stringent in several respects than the requirements which are applicable to shipping containers or other containers for the short-term storage of nuclear fuel. While container devices of the last-mentioned category have to admit of safe storage for periods of time which may be several decades, container devices for the ultimate storage have to be safe for substantially longer periods of time, such us several centuries or even thousands of years. For example, in a current research and development project aiming at creating an ultimate repository in the state of Nevada in the United States, a prerequisite is that the storage of the radioactive material must be safe for tens of thousands of years. Among the requirements to be met is that which requires the container devices to withstand extreme mechanical loads, both short and long-term static and dynamic loads and chock loads, such as loads that can occur as a result of earthquakes and other seismic movements or in connection with nuclear detonations or other war or terrorist operations. Other requirements to be met are those which call for extremely long-term stability, such as resistance to corrosion or other decomposition or ageing phenomena, even under the influence of heating caused by the contained nuclear fuel, occurring in the materials of the container devices, or at least the material of parts whose failure compromise the safety. An object of the invention is to provide a container device that is suitable for the ultimate disposal of nuclear fuel and can be expected to offer a fully reliable containment of stored nuclear fuel throughout the period of time for which that material is to be regarded as a hazardous material. To that end the invention provides the container device that is set forth in the independent claim. Preferred and advantageous embodiments of the device are set forth in the dependent claims. As will be apparent from the following description of the invention, the container device according to the invention comprises certain elements which are prior art in respect of storage of nuclear fuel or other highly hazardous materials, such as the prior art disclosed in WO91/05351 (or U.S. Pat. No. 5,327,469) and WO96/21932 (or U.S. Pat. No. 6,008,428). However, it will become apparent that the container device is nevertheless non-obvious over the prior art. The invention also relates to a method and an installation for making container devices according to the invention. A feature of the container device according to the invention which is essential for the achievement of the stated object resides in a kind of box-in-box construction of the finished, sealed container device in which a number of concrete barriers alternate with metal barriers between the nuclear fuel and the outer side of the container device. Basically, the number of such barriers can be unlimited and selected in accordance with the desired degree of safety. If a barrier should become damaged by force or corrosion or fail for some other reason, other barriers remain to prevent nuclear material from coming out of the container. The following description, including the drawing figures, of the container device of the invention and of the method and the installation for making it is limited to what is essential for the understanding of the invention. As is readily appreciated, the implementation of the invention requires a good deal of matter that is not illustrated or described, but the person skilled in the art, guided by the description that follows, can add what is lacking merely by exercising his skill. The container device 11 illustrated in the drawings is adapted to contain four identical nuclear-fuel bodies formed by nuclear-fuel assemblies. FIGS. 4 and 5 diagrammatically show the outlines of such a fuel assembly F. The fuel assemblies F are nuclear fuel units each containing a set of fuel rods (not shown) in which the nuclear fuel proper is enclosed. Naturally, the number of nuclear-fuel assemblies can be different from that in the illustrated exemplary embodiment. Each fuel assembly F is enclosed in a first sub-container or containment body A which is in the shape of an elongate cylindrical body of square cross-section (naturally, the cross-section may alternatively be round or of a different non-square shape) and comprises a casing wall 12 of sheet metal and end walls 13A and 13B formed respectively of an upper metal plate and a lower metal plate. In the compartment 14 formed by the casing wall 12 and the end walls 13A, 13B rods 15 are secured to each end wall to carry support members 16 at a distance from the end walls. These support members hold between them the nuclear-fuel assembly F such that there is an open space between the fuel assembly and the inner side of the casing wall 14. Each of the two end walls 13A, 13B has a central opening formed by a sleeve 17A, 17B. These sleeves are schematic representations of means not shown in detail which are used for the introduction of a casting compound—this casting compound may be glass or concrete and is here assumed to be the latter kind of casting compound—into the open space in the compartment 14 after the fuel assembly F has been mounted in the compartment. The concrete may be forced through opening in the ends of the fuel assembly and/or its sides and fill the open spaces of the fuel assembly such that the fuel rods will also be surrounded by concrete. Such means may comprise a valve through which the concrete is introduced and a valve through which excess concrete is forced out of the containment body A. This valve may be adapted to open only after a certain pressure exists in the compartment such that the concrete will have to be supplied under a given pressure. In the completed container device the first containment body A is surrounded by a second sub-container or containment body B. This containment body is in the shape of an elongate cylindrical body of circular cross-section and comprises a casing wall 18 of sheet metal and end walls 19A and 19B formed of a lower end plate and an upper end plate, respectively. Slightly inwardly of the casing wall a number of perforated tubes 20 are anchored in the end walls 19A, 19B to serve as prestressed reinforcing members 20. In FIG. 7, four such tubes 20 are shown but the number of tubes can be different, such as eight. To each of the end walls 19A, 19B eight support members 21 (see particularly FIGS. 6 and 7) are secured to retain the first four containment bodies A in the compartment 22 defined by the casing wall 18 and the end walls 19A, 19B such that these containment bodies are jointly fixed in an axially and radially centred position relative to the second containment body B with a spacing relative to both the casing wall 18 and the end walls 19A, 19B as is best seen in FIG. 3. The space defined by the casing wall 18 and the end walls 19A, 19B that thus exists between the first containment body A and the second containment body B is considerably larger than the corresponding space in the first containment bodies, and like the latter space it is completely filled with concrete in the finished container device 11. The walls of the hollow cylindrical concrete body that encloses the first containment bodies A within the completed container device thus are substantially thicker than the walls of the concrete body that encloses the fuel assemblies in the first containment bodies A. In a corresponding manner and for the same purpose as the end walls 13A, 13B of the first containment bodies A, the end walls 19A, 19B are each provided with a central opening formed by a sleeve 23A, 23B. The second containment body B is enclosed by a third containment body C which is constructed in substantially the same manner as the containment body B. Thus, the containment body C comprises a circular cylindrical casing wall 24 and upper and lower end walls 25A, 25B. These walls define a compartment 26 which houses perforated axial tubes 27 which are anchored in the end walls to serve as pre-stressed reinforcing members. In this case the number of tubes 27 is eight. To each of the end walls 25A, 25B eight support members 28 are secured to retain the second containment body B in a radially and axially centred position in the compartment 26. The space that exists in the compartment 26 between the second containment body B and the third containment body C is filled with concrete in the completed container device. To permit the filling with concrete, the end walls 25A, 25B are provided with central openings formed by sleeves 29a, 29B similar to the sleeves 23A, 23B. In the illustrated embodiment there is also a fourth containment body D in which the third containment body C is enclosed in a radially and axially centred position and which is substantially identical with the containment body C apart from the dimensions. Accordingly, the containment body D comprises a circular cylindrical casing wall 30 and upper and lower end walls 31A, 31B. These walls define a compartment 32 which houses perforated axial tubes 33 anchored in the end walls to serve as pre-stressed reinforcing members. In this case as well, the number of tubes 33 is eight. To each of the end walls 31A, 31B eight support members 34 (shown only in FIG. 3) are secured to retain the third containment body C in a radially and axially centred position in the compartment 32. The space in the compartment that is formed between the third containment body C and the fourth containment body D is filled with concrete in the completed container device. To permit the filing with concrete the end walls 31A, 31B have central openings formed by sleeves 35A, 35B similar to the sleeves 23A, 23B and 29A, 29B. As will be appreciated, the drawing figures show the container device according to the invention in simplified form and with omission of many details which form no part of the invention and do not have to be illustrated and described to enable the person skilled in the art to carry out the invention. For example, as a practical matter, the sub-containers or containment bodies A to D have to be provided with auxiliary elements enabling lifting and other manipulations of them, possibly also measuring or monitoring devices. An overview of an installation and a method for manufacturing the container device according to the invention is shown in FIG. 10. To simplify the illustration, only so much of the installation is shown as is necessary for manufacturing a container device comprising the containment devices A and B in FIGS. 1 to 3. However, the illustrated installation can readily be expanded to be useful for manufacturing container devices which also comprise the containment body C or the containment bodies C and D. As shown schematically in FIG. 10 the installation resembles the installation disclosed in WO01/78084 A1, e.g. in that the manufacture is carried out under water in a basin system with a number of concrete sections, but it also has important differences over that installation in respect of the means and the method for the manufacture. A main part of the installation comprises a basin 40 with a row of basin sections 41, 42, 43, 44, 45. Adjacent basin sections can be connected with and disconnected from one another by means of water gates such that components of the container devices and the container devices themselves can be transferred in a submerged position from one basin section to the next. Nuclear fuel units, formed by fuel assemblies F in the illustrated example, which are to be contained in container devices according to the invention and are stored in, for example, a central temporary storage K for spent nuclear fuel, are transferred to the basin 40 in a shipping container T. They are transferred from the shipping container T to the first basin section 41 in which they are placed in a submerged position. Main components of the first sub-container or containment body A (FIGS. 4, 5) are also transferred to the first basin section. These components are, firstly, a unit formed by the casing wall 12, the lower end wall 13B, which is connected to the casing member and has the lower rods 15 and the lower support member 16 attached to it, and, secondly, the upper end wall 13A, the upper rods 15 and the upper support member 16. In FIG. 10, the first-mentioned elements are represented by the casing wall 12 and the last-mentioned elements are represented by the upper end wall 13A. The aforesaid unit is placed under water in the basin section, optionally positioned in a holder that contributes to firmly retaining the unit in an upright position. A fuel assembly F is placed in each unit whereupon the upper support member 16, the rods 15 and the upper end wall 13A are attached. Then the unit so formed, which does not yet constitute the finished containment body A, is transferred, still submerged, to the second basin section 42 where it is filled with concrete to form a body which is monolithic in the sense that it is essentially free from voids. In the second basin section 42 the containment body A is positioned on a casting platform 46 which is mounted on the bottom of the basin section and connected to a concrete supply line 47. A casting head 48 is mounted on the upper end of the containment body. Concrete (casting compound) is supplied at a high pressure, preferably several decabar, from a concrete station 49 to the casting platform 46 and axially through the containment body A so that the containment body is completely filled with concrete at a high pressure. Excess concrete is carried away through a discharge line 50. When the containment body a is filled with concrete, the nuclear fuel rods in the fuel assembly will also be embedded in concrete. Thus, the fuel rods will be well protected against cracling or other damages during the handling of the fuel assemblies or the container device and for practical purposes also against attempts at getting access to the nuclear fuel for illegal or otherwise undesired use of the stored nuclear fuel. In addition, the protection against leakage from the fuel rods is improved. When the casting is completed, the openings of the sleeves 18A, 18B in the end walls 13a, 13B through which the concrete is forced into the containment body and excess concrete is discharged will also be filled with concrete so that the finished containment body will be completely sealed. After completion of the casting an auxiliary device 51 is mounted on the upper end of the finished containment body A to facilitate manipulation thereof. The concrete in the containment body is allowed to set for a suitable period in the basin section 43 before it is transferred to the next basin section 44 where the containment body B will be made. Broadly, the containment body B is made as described with reference to the containment body A. The containment bodies A are transferred to the basin section 44 where they are united with the separately made main components of the containment body B, that is, a unit which is essentially formed by the casing wall 18, the lower end wall 19B, the tubes 20 and the lower set of support members 21, and the upper end wall 19A and the upper set of support members 21. In FIG. 10, the first-mentioned elements are represented by the casing wall 18 and the last-mentioned elements are represented by the upper end wall 19A. In the basin section 44 the four containment bodies A are inserted in the above-mentioned unit, represented by the casing wall 18, whereupon the upper end wall 19A is attached and the reinforcing tubes 20 are tensioned. Filling of the space around the four containment bodies A within the containment body B with concrete at a high pressure, e.g. 10 to 50 bar, by means of a casting platform 52 mounted on the bottom of the basin section and a casting head 53, then takes place in substantially the same manner as the filling of the containment bodies A with concrete. The concrete is pumped through a concrete supply line 54 from a concrete station 55 and excess concrete is carried away through a discharge line 56. As was the case when the containment body A was filled, the openings of the end wall sleeves 23A, 23B through which the concrete is supplied and excess concrete is discharged will be filled with concrete when the casting operation is completed, see FIG. 1. The high concrete pressure contributes to the pre-tensioning of the tubes 20. When the casting is completed, an auxiliary device 57 is attached to the upper end of the completed containment body B to facilitate manipulation thereof. The concrete in the containment body B is allowed to set for a suitable period in the basin section 44 or in the next basin section 45 before it is carried away, e.g. to an ultimate storage. In the final phase of the casting the concrete can be subjected to a vacuum treatment with the aid of the tubes 20 which can then be filled with concrete. If the container device is also to comprise the containment body C, the procedure described above is repeated, either in the basin section 44 or in a separate basin section. The same applies if the container device is also to include the containment body D. Preferably, the concrete used for the casting is high-quality concrete. For the innermost containment body A it may be appropriate to use ore concrete which is advantageous in respect of the casting operation and also in respect of the heat conductivity and thereby the dissipation of heat from the nuclear fuel. In the above-described method of manufacturing the container device according to the invention, the concrete is cast in the containment bodies from below and upwards, but the casting can also take place in the opposite direction, and it is also possible to feed the concrete and discharge the excess concrete at one and the same end of the containment body, preferably at the upper end. These and other modifications of the container device described above and the method and installation for manufacturing it are within the scope of the invention as defined by the claims.
	description	This application claims the benefit of U.S. Provisional Application No. 61/509,715, filed Jul. 20, 2011, the disclosure of which is hereby incorporated by reference in its entirety. This invention was made with government support under Contract No. DE-AC05-00OR22725 awarded by the U.S. Department of Energy. The government has certain rights in the invention. The present invention relates to systems for the storage, transportation and disposal of used nuclear fuel assemblies. Used fuel assemblies are a primary byproduct of power-generating nuclear processes, and must generally be stored or disposed of in a manner that limits any impact on the surrounding environment. Temporary storage solutions include the fixation of used fuel assemblies in dry casks, termed dry cask storage. Long term disposal is in many ways preferable to dry cask storage, however, and a number of repository concepts are actively being considered. Many existing dry casks do not satisfy the expected package size limitations for the direct disposal of used nuclear fuel assemblies at the proposed repositories. As a result, used nuclear fuel assemblies may require repackaging into more suitable containers for transportation and/or disposal. However, repackaging used nuclear fuel assemblies creates tremendous radiological, operational and financial liabilities, particularly following an extended storage period. Currently, storage and transportation are considered separately from disposal under relevant U.S. regulations. For example, the used nuclear fuel management system operates under multiple regulations, e.g., 10 CFR 72 for storage, 10 CFR 50 and 72 for dry cask loading, 10 CFR 71 for transportation, and similar regulations to 10 CFR 60 and 63 for eventual disposal. Existing regulations for storage require the used nuclear fuel to be retrievable. Existing regulations for transportation do not explicitly require that fuel rods be intact or undamaged, and relevant provisions allow for specially designed canisters to move damaged fuel. Transportation regulations currently limit fuel to a maximum burnup of 45 GWd/MTU, primarily based on limited information available on the mechanical properties of high burnup cladding as well as the effects of long-term storage on high burnup (>45 GWd/MTU) fuel. Existing regulations for disposal are specific to the previously planned Yucca Mountain Repository, but are likely to be modified, perhaps substantially, to meet future repository site and geologic media performance objectives, perhaps depending on the geologic media, e.g., clay/shale, salt, or crystalline rock. Because the disposal requirements are currently open-ended and undefined, there is at present no domestic market for dry casks designed to support disposal operations. As a result, storage and transportation casks are being designed, licensed and loaded without regard for disposal operations and requirements. An integrated storage, transportation and disposal system for used nuclear fuel assemblies is provided. The system includes a plurality of sealed canisters, each containing four or more used fuel assemblies, and a cask sized to receive the sealed canisters. The sealed canisters are inserted within the cask for storage and/or transportation, and the sealed canisters are removed from the cask for disposal at a designated repository. The system of the present invention allows the handling of sealed canisters separately or collectively, while allowing storage and transportation of high burnup fuel and damaged fuel. In one embodiment, the sealed canisters include longitudinal reinforcing members and radiation-absorbing panels. The longitudinal reinforcing members surround the used fuel assemblies, while the radiation-absorbing panels are interposed between the used fuel assemblies. The longitudinal reinforcing members are generally positioned along the canister sidewall to stabilize the used fuel assemblies within the canister enclosure. The reinforcing members include a u-shaped cross-section and upper and lower hemispherical ribs extending radially within the canister enclosure. The radiation-absorbing panels include a chevron-shaped cross section and are interposed between adjacent used fuel assemblies along the length of the canister enclosure. In another embodiment, the sealed canisters include a removable closure or lid for the extraction of used fuel assemblies. Each used fuel assembly is self-contained within a fuel basket tube, optionally sized for deep borehole disposal, and each fuel basket tube includes primary and secondary retrieval mechanisms. The retrieval mechanisms facilitate the removal of the fuel basket tubes from the canister, if desired, with added redundancy in instances where one retrieval mechanism is no longer viable. In still another embodiment, the cask includes a base and a cylindrical sidewall defining an interval volume sized to receive a plurality of sealed canisters in side by side relationship. The cask includes a basket assembly nested within the cask enclosure and having a central region and a plurality of basket cells radially outward of the central region. The central region can accommodate damaged fuel cans or greater than class C (GTCC) waste, and the cylindrical sidewall can include a concrete overpack for upright storage of the cask. The cask—with the sealed canisters inside—can be loaded into a larger transport cask and shipped for direct disposal or reprocessing of the used fuel assemblies. Alternatively, the sealed canisters can be repackaged into an alternative transport cask for truck transportation, potentially eliminating the need for direct rail access. The cask can be reused in many instances, particularly where the cask is not used in disposal operations. In various embodiments, the present invention provides a multi-canister system having superior assembly and burnup capacity over known systems while also minimizing the number of cask loadings required to manage a used nuclear fuel inventory. The multi-canister system can also enable a higher percentage of fuel to meet subcriticality requirements. The multi-canister system is adapted for a wide range of geologic media, including tuff, clay/shale, salt, and crystalline rock, and can reduce the life-cycle cost for used fuel storage, transport and disposal. These and other features and advantages of the present invention will become apparent from the following description of the invention, when viewed in accordance with the accompanying drawings and appended claims. The invention as contemplated and disclosed herein includes an integrated, multi-canister system to meet current and future requirements for storage, transportation and disposal of used nuclear fuel assemblies. As explained in greater detail below, the integrated system includes modular canisters received within a cask for storage and transportation and removable from a cask for disposal. Referring now to FIGS. 1-3, a cask is illustrated and generally designated 10. The cask 10 includes cylindrical shell 12 defining an internal cask volume. The cylindrical shell 12 can optionally including a steel, cement or concrete overpack. In use, the cask 10 is positionable in an upright storage configuration on a storage pad meeting applicable storage requirements for used nuclear fuel assemblies. The cask 10 can alternatively include horizontal storage or in-earth storage with suitable seismic constraints. As also shown in FIGS. 1-3, the cask 10 includes an internal basket assembly 14 including multiple canister basket cells 16 for receiving at least one canister 20. The basket assembly 14 can include multiple vertical reinforcing spars, optionally in a polygonal honeycomb configuration, and further optionally a pentagon, hexagon, heptagon, octagon or other configuration. As shown in FIG. 3, for example, the basket assembly 14 can include a central, pentagon-shaped sidewall 15 extending along the length of the cask 10. The pentagon-shaped sidewall 15 defines a central region 17 to accommodate damaged fuel cans or GTCC waste. Five y-shaped spars 18 extend axially along the length of the cask 10, and radially from the corners of the pentagon-shaped sidewall 15 toward the outer cylinder sidewall 12. The y-shaped spars 18, the pentagon sidewall 15, and the cylindrical sidewall 12 cooperate to define five basket cells 16 for five canisters 20, each basket cell 16 being disposed radially outward of a cask centerline. The basket assembly 14 is a monolithic structure in the present embodiment, optionally being removeable axially from the cask 10 but prohibited from rotating with respect to the cask 10. For example, the cask 10 can include a clip for each y-shaped spar 18 abutting the cylinder sidewall 12 to prevent rotation of the basket assembly 14 within the cask 10. The basket assembly 14 can be formed from steel in the present embodiment, but other materials may be used as desired. The basket assembly 14 can meet thermal requirements for the system, while the individual canisters 20 can meet structural and subcriticality requirements for storage, transportation, and disposal. The cask 10 can additionally include a base 21 and a lid 22 with hooks 23 for removal of the lid 22 from the canister sidewall 12 as shown in FIG. 2. The sealed canisters 20 are positionable within the cask 10, and more specifically, the canister basket cells 16, in side by side relationship. In addition, the cask 10 can be loaded into a larger transport cask and sent to direct disposal or reprocessing. Alternatively, the canisters 20 can be repackaged from the cask 10 into a special purpose transport cask for truck transport or rail transport. Referring now to FIGS. 4-7, a canister 20 includes a base or end 24, a sidewall 26, and a lid 28 to cooperatively define an enclosure for containing a plurality of used nuclear fuel assemblies 30 therein. The canister 20 is cylindrically-shaped in the present embodiment, but can include other shapes or geometries in other embodiments. For example, the canister 20 can be box-shaped and can include a four-sided sidewall 26 if desired. Each fuel assembly 30 is self-contained within a fuel basket tube 32, and multiple fuel basket tubes 32 are received within the canister 20 in side by side relationship. In the illustrated embodiment, the canister sidewall 26 includes an inner diameter of about 68 cm and an outer diameter of about 78 cm, and the cask 10 includes an inner diameter of about 210 cm. These dimensions are exemplary, however, and the cask 10 and containers 20 can be larger or smaller than depicted herein. As also shown in FIGS. 4-7, the canister 20 includes multiple longitudinal reinforcing members 34 to stabilize the used fuel assemblies within the canister enclosure. In particular, the longitudinal reinforcing members 34 extend axially within the canister enclosure and outward of the canister centerline, being interposed between the fuel basket tubes 32 and the canister sidewall 26. Multiple longitudinal reinforcing members 34 are stacked atop one another as generally shown in FIGS. 4-5, collectively extending from the canister base 24 to the canister lid 28. For example, the canister 20 includes four columns of reinforcing members 34 in the present embodiment, with each column abutting two fuel basket tubes 32, such that the fuel basket tubes 32 are sandwiched between the reinforcing members 34 and are spaced apart from the canister sidewall 26. In other embodiments, however, a single longitudinal reinforcing member 34 will extend along the length of the canister 20. As perhaps best shown in FIG. 7, each reinforcing member 34 includes a u-shaped sidewall 36 that terminates in lower and upper hemispherical ribs 38, 40 that extend radially within the canister enclosure. The u-shaped sidewall 36 includes a major web 35 and two spaced-apart minor webs 37, 39 extending generally perpendicularly from the periphery of the major web 35. The lower and upper ribs 38, 40 are spaced apart from each other along the length of the reinforcing member 34 and add torsional rigidity to the reinforcing member 34, while also functioning as a heat conduit from the fuel basket tubes 32 to the canister sidewall 26. Collectively, the reinforcing members 34 and the fuel basket tubes 32 provide structural support to maintain the used nuclear fuel assemblies 30 in a predetermined orientation within each canister 20. As shown in FIG. 6, the canister 20 includes multiple radiation-absorbing panels 42 between adjacent fuel basket tubes 32. The radiation-absorbing panels 42 include a v-shaped or chevron-shaped cross-section in the present embodiment as shown in FIG. 8, generally extending along the length of the canister enclosure. In particular, two radiation-absorbing panels 42 are shown in FIG. 6, forming a t-shaped partition along the longitudinal center of the canister enclosure. The radiation-absorbing panels 42 can be formed of any material adapted to absorb or suppress radiation, for example neutron radiation. In the present embodiment, for example, the radiation absorbing panels 42 include borated stainless steel to suppress interaction of adjacent used fuel assemblies 30. In addition, the canister 20 includes one or more drain ports 44 for the evacuation of water from the canister enclosure. One drain port 44 is shown in FIG. 6, but any number of drain ports can be utilized as desired. As noted above, each used fuel assembly 30 is self-contained within a fuel basket tube 32. A typical used fuel assembly 30 can include uranium rods within zircaloy tubes bundled in a rectangular configuration. As shown in FIG. 9, the fuel basket tube 32 can include a rectangular sidewall 46, optionally a stainless steel shell, including a wire mesh insert 48 at a lower portion thereof to meet existing damaged fuel requirements for containment. The fuel basket tube 32 functions as a structural support piece within the canister enclosure, and is optionally sized for deep-bore disposal within a geologic repository. Each fuel basket tube 32 can accommodate two fuel assembly's worth of fuel rods when rods are consolidated out of the assembly lattice configuration. As also shown in FIG. 9, the fuel basket tube 32 includes a chair 50 seated atop a wire mesh tray 52. The chair 50 functions as a spacer between the wire mesh tray 52 and the fuel rods. Different chairs can accommodate different fuel rods. That is, a shorter chair can accommodate longer fuel rods, while a longer chair can accommodate shorter fuel rods. The fuel basket tube 32 additionally includes a sheath bottom 54 and a sheath foot 56 at the base of the fuel basket tube 32. In addition, the fuel basket tube 32 includes a redundant retrieval mechanism for handling fuel assemblies. In the illustrated embodiment, the primary retrieval mechanism is consistent with how used fuel was originally loaded where the fuel assembly handle is hoisted by a grapple arm. The secondary retrieval mechanism includes an aperture or a recess 58 in the fuel basket tube sidewall 46, optionally each face of the sidewall 46, to receive a corresponding mating member that also caps the tube making it suitable for borehole disposal. In use, the fuel assemblies can be hoisted from the canister 20 using the primary retrieval mechanism, with added redundancy in the second retrieval mechanism 58 if the first retrieval mechanism becomes damaged or compromised. The system of the present invention is well suited for the storage, transportation and disposal of used fuel assemblies from Pressurized Water Reactor (PWR) systems and Boiling Water Reactor (BWR) systems. Advantageously, a single cask 10 can include canisters from both systems. The smaller BWR assemblies can be received within the same sized canister for containing PWR assemblies. For example, a nine-assembly BWR canister 20 is shown in FIGS. 10-11. The radiation-absorbing panels 42 slide between adjacent fuel basket tubes 32 as generally described above in connection with FIG. 6. Though depicted as being unitary in FIG. 10, the panels 42 are typically moveable with respect to each other, allowing the replacement of a single panel without requiring the removal of the remaining panels. In addition, spaced apart thermal shunts 60, 62 traverse the central region of the canister to facilitate heat removal from the central fuel basket tube 64 to left and right reinforcing members 66, 68, and then the cylinder sidewall 26. The thermal shunts 60, 62 can be formed from aluminum and can extend along the height of the canister 20. The number, orientation and placement of the radiation-absorbing panels 42 can vary to meet criticality requirements. In some instances, for example, the radiation-absorbing panel 42 will extend between some, but not all, of adjacent fuel basket tubes 32. A method for processing used nuclear fuel assemblies in accordance with the above described system includes loading multiple fuel basket tubes into the modular canisters, where each fuel basket tube includes a single used fuel assembly, inserting the modular canisters into a cask for storage at a first facility, transporting the canisters to a second facility (optionally while self-contained within the cask), and removing the canisters and optionally the fuel basket tubes for disposal or reprocessing at the second facility. Loading operations can optionally take place within a cooling pool, including loading used nuclear fuel into the canister while submerged in water. A subsequent drying operation includes filling the canister with a non-reactive gas, for example helium, nitrogen, argon, neon, radon, krypton or xenon. Disposal operations include optional deep bore disposal of the fuel basket tube and/or the canister within a designated geologic repository. The system and method of the present invention can eliminate the need for repackaging fuel assemblies, as the fuel assemblies generally remain in the containers 20 across storage, transportation and disposal operations. In addition, the system and method allow improved decay heat management of high burnup and mixed oxide fuel, and can enable an increased percentage of fuel acceptable in terms of subcriticality requirements for various modes. The system also provides a technical basis for meeting transportation requirements based on moderator exclusion. For those facilities that have not begun dry cask storage, the lighter canisters 20 provide increased options and are expected to offer more efficient drying processes over conventional systems. The present invention can also eliminate the need for Independent Spent Fuel Storage Installation (ISFSI) pads for dry cask storage by allowing in-ground storage or above-ground shielded structures. In addition, the present invention enables retrievability regardless of the fuel condition, including the handling of damaged fuel assemblies before and after transport to a disposal facility. The above description is that of current embodiments of the invention. Various alterations and changes can be made without departing from the spirit and broader aspects of the invention as defined in the appended claims, which are to be interpreted in accordance with the principles of patent law including the doctrine of equivalents. Any reference to elements in the singular, for example, using the articles “a,” “an,” “the,” or “said,” is not to be construed as limiting the element to the singular.
	claims	1. A method for treating a radioactive liquid effluent of medium activity, wherein calcination of said effluent, to which is optionally added a calcination adjuvant, is carried out in order to obtain a calcinate, and a vitrification adjuvant for producing an alumino-borosilicate glass is then added to said calcinate, the vitrification adjuvant having the following composition expressed in percentages by mass:SiO2: 58 to 65B2O3: 15 to 19Na2O: 5 to 10Al2O3: 0 to 3Li2O: 1 to 4CaO: 1.5 to 4ZrO2: 0 to 3Fe2O3: 2 to 4NiO: 0 to 2CoO: 0 to 2,it is proceeded with the melting of said calcinate and of said vitrification adjuvant in a cold crucible in order to obtain a glass melt, and said glass melt is then cooled down, whereby the alumino-borosilicate glass is obtained having the following composition expressed in percentages by mass based on the total mass of the glass:a) SiO2: 45 to 52b) B2O3: 12 to 16.5c) Na2O: 11 to 15d) Al2O2: 4 to 13e) one or more element(s) ETR selected from oxides of transition elements and platinoids: where ETR is in the range of >0 to 5.25;f) One or more element(s) TRA selected from rare earth oxides and from actinides oxides: where TRA is in the range of 0 to 3.5;g) ZrO2: 0 to 4h) Other elements AUT of the effluent: where AUT is in the range of 0 to 4;and the composition of the glass further satisfies all of the following inequations in which the SiO2, Al2O3, B2O3, Na2O, ETR, AUT are expressed in percentages by mass based on the total mass of the glass:SiO2+Al2O3<61% (1)71%<SiO2+B2O3+Na2O<80.5% (2)B2O3/Na2O>0.9 (3)0.7 Al2O3−ETR<5% (4)Al2O3/ETR>2.5 (5)0.127(B2O3+Na2O)>AUT. (6) 2. The method according to claim 1, wherein the other elements constitutive of the effluent (“AUT”) are selected from the following oxides: SO3, P2O5, MoO3, and BaO. 3. The method according to claim 1, wherein the vitrification adjuvant is characterized in that it is in the form of a glass frit. 4. The method according to claim 1, wherein the vitrification adjuvant is characterized in that it is in the form of a mixture of chemical products, especially of oxides, in the form of powders. 5. The method according to claim 1, wherein the radioactive liquid effluent of medium activity contains the following elements in the following contents:Na: from 30 g/L to 80 g/LB: from 0 g/L to 5 g/LMn: from 0 g/L to 1 g/LCe: from 0 g/L to 14 g/LFe: from 0 g/L to 3 g/LNi: from 0 g/L to 1 g/LCr: from 0 g/L to 1 g/LZr: from 0 g/L to 16 g/LMo: from 0 g/L to 10 g/LP: from 0 g/L to 4 g/LS: from 0 g/L to 1.7 g/LBa: from 0 g/L to 7 g/LGd: from 0 g/L to 1 g/LTc: 1 g/L or lessActinides: from 0 g/L to 8 g/LPlatinoids: 1 g/L or less;the total content of said elements being from 30 g/L to 154.7 g/L. 6. The method according to claim 5, wherein the radioactive liquid effluent contains the following elements in the following contents:Na: 55 g/LB: 2.5 g/LMn: 0.5 g/LCe: 7 g/LFe: 1.5 g/LNi: 0.5 g/LCr: 0.5 g/LZr: 8 g/LMo: 5 g/LP: 2 g/LS: 0.85 g/LBa: 3.5 g/LGd: 0.5 g/LTc: 1 g/LActinides: 4 g/LPlatinoids: 1 g/L;the total content of said elements being 93.35 g/L. 7. The method according to claim 1, wherein the calcination adjuvant is selected from aluminium nitrate, iron nitrate, zirconium nitrate, rare earth nitrates, and mixtures thereof. 8. The method according to claim 7, wherein the calcination adjuvant is a mixture of aluminium nitrate and of iron nitrate. 9. The method according to claim 5, wherein the Na2O/(sum of the oxides in the calcinate) ratio is less than or equal to 0.3. 10. The method according to claim 5, wherein the vitrification adjuvant is as defined in any one of claims 4 to 5. 11. The method according to claim 5, wherein the melting of the calcinate and of the vitrification adjuvant is carried out a temperature from 1,200° C. to 1,300° C. preferably 1,250° C. 12. The method according to claim 1 wherein the oxides of transition elements are selected from Fe2O3, Cr2O3, MnO2, and TcO2. 13. The glass according to claim 1 wherein the platinoids are selected from RuO2, Rh, and Pd. 14. The method according to claim 1 wherein the rare earth oxides are selected from La2O3, Nd2O3, Gd2O3, Pr2O3, and CeO2. 15. The method according to claim 1 wherein the actinides oxides are selected from UO2, ThO2, Am2O3, PuO2CmO2, NpO2. 16. The method according to claim 8, wherein the calcination adjuvant mixture of aluminium nitrate and of iron nitrate has the following proportions relating to the contents: 0.66<Al2O3/(Al2O3+Fe2O3)<1 wherein the contents are oxide contents by mass.
	abstract	A flexible multi-leaf collimator for electron radiotherapy is provided, where the leaves are not a single rigid component, but are configured in a manner that curves away from the patient to provide greater clearance. The invention includes a plurality of flexible assemblies, at least one guide supporting the assemblies, and a plurality of assembly drivers. The driver engages the assembly and moves the assembly along the guide. The assembly has an extended state and a retracted state relative to the guide, such that when in the extended state the assembly is held in the aperture plane and when in the retracted state the assembly conforms along the guide. When in the extended state the assemblies are disposed as a treatment aperture.
054870941	description	DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described with reference to the accompanying drawings, which is an apparatus for manufacturing double-layer pellets whose cores are made of tritium. FIG. 1 is a sectional view of the entire apparatus. As shown in FIG. 1, the apparatus has a casing 1. The casing 1 comprises a main casing 2 consisting of four side walls, a top wall 4 closing the upper end of the main casing 2, a bottom wall 5 closing the lower end of the main casing 2, and a tubular casing 6 horizontally projecting from one side of the main casing 2. The tubular casing 6 covers a part of a pellet-ejecting barrel 48, which will be described later. The casing 1 is evacuated to a high vacuum by means of a vacuum pump (not shown). Provided within the casing 1 are heat exchangers 7 and 8 and rectangular cooling blocks 9 and 10. The cooling blocks 9 and 10 are made of oxygen-free copper; they oppose each other and are spaced apart from each other by a predetermined distance. The heat exchangers 7 and 8 are connected to the cooling blocks 9 and 10, respectively, for cooling the blocks 9 and 10. A helium liquid (or low temperature helium gas) inlet pipe 11 and a helium gas outlet pipe 12 are connected to the heat exchanger 7, respectively for supplying liquid helium (or low temperature helium gas) into the heat exchanger 7 and guiding helium gas therefrom. Similarly, a helium liquid (or low temperature helium gas) inlet pipe 13 and a helium gas outlet pipe 14 are connected to the heat exchanger 8, respectively for supplying liquid helium (or low temperature helium gas) into the heat exchanger 8 and guiding helium gas therefrom. The heat exchangers 8 and 9, the inlet pipes 11 and 13 and the outlet pipes 12 and 14 constitute means for cooling a pellet carrier disc 15, which will be described later. In operation, liquid helium (or low temperature helium gas) flows into the heat exchangers 7 and 8 through the inlet pipes 11 and 13. It circulates in the heat exchangers 7 and 8. While circulating in the heat exchangers 7 and 8, the liquid helium evaporates (or the low temperature helium gas warms up), cooling the heat exchangers 7 and 8. The helium gas flows from the heat exchangers 7 and 8 through the outlet pipes 12 and 14. The pellet carrier disc 15, used as a pellet carrier, is closely sandwiched between the cooling blocks 9 and 10 such that the disc 15 can be moved up and down. The disc 15 has a through hole 16 which serves to indicate the position of the disc 15. To be more specific, a laser 3 located outside the casing 1 emits a beam. The beam is applied through a vacuum window 17 made in the main casing 2, passes through the hole 16 of the disc 15, and emerges through a vacuum window 18 made in the main casing 2. Hence, the position of the pellet carrier disk 15 can be determined from the brightness of the beam as seen at the vacuum window 18. Drive shafts 19 and 20 are connected, at one end, to the pellet carrier disk 15, for moving the disc 15 up and down with respect to the cooling blocks 9 and 10. The drive shafts 19 and 20 are connected, at the other end, to a drive mechanism (not shown). A position detector (not shown) is mounted on each drive shaft, for detecting the position of the pellet carrier disc 15. The position of the disc 15 can be determined with high accuracy by the position detectors on the drive shafts 19 and 20 and the observation of the laser beam at the vacuum window 18. Elongation of the disc 15, if any, can therefore be reliably detected. The heat exchangers 7 and 8, the cooling blocks 9 and 10, and the like are stationarily supported by support plates 21 and 22 which are secured to the main casing 3. The cooling block 10 has circular through holes 25 to 30 which extend horizontally and parallel to one another. The holes 25, 26, 27, 28, 28 and 30 are arranged in the order mentioned from top to bottom, with their axes present in the same vertical plane. The pellet carrier disk 15 has a circular through hole 31 which horizontally extends and has substantially the same diameter as the holes 25 to 30 of the cooling block 10. The hole 31 can be set into axial alignment with any one of the holes 25 to 30 of the cooling block 10 as the disk 15 is moved up and down by the drive shafts 19 and 20. More specifically, when the disc 15 takes the position shown in FIG. 1, the hole 31 axially aligns with the fourth hole 28 of the cooling block 10. To make the hole 31 align with the fifth hole 29 located below the fourth hole 28, the pellet carrier disk 15 is moved downwards by the drive shafts 19 and 20. The first hole 25 of the cooling block 10 communicates with a pipe 32 which is used as first material-supplying means, so that deuterium gas supplied through the pipe 32 may solidify in the first hole 25. In operation, deuterium gas is introduced into the first hole 25 through the pipe 32 while the hole 31 of the disc 15 remains aligned with the first hole 25 as shown in FIG. 2A. The deuterium gas then solidifies, forming a deuterium block or cylinder 33, as shown in FIG. 2B, in the hole 31 of the disc 15 which has been cooled. A bushing 36 is fitted in the second hole 26 of the cooling block 10. Movably inserted in the bushing 36 is a shaft 35 used as hole-making means for making a hole in the deuterium cylinder 33. The shaft 35 has a distal end portion, which has a circular cross section and a diameter far smaller than that of the second hole 26. In operation, the shaft 35 is moved in the direction of the arrow shown in FIG. 3A, while the hole 31 of the disk 15 remains aligned with the second hole 26. The shaft 35 is moved until its distal end portion thrusts into the deuterium cylinder 33 for a prescribed distance from one end of the cylinder 33. The prescribed distance depends on the length of a core to be formed in the deuterium cylinder 33. It is, for example, about half the thickness of the pellet carrier disc 15. Thereafter, the shaft 35 is pulled from the deuterium block 33, in the direction of the solid-line arrow shown in FIG. 3B. As a result, a hole 34 is made in the deuterium block 33. It is in this hole 34 that a tritium cylinder will be formed as will be described later. Inserted in the third hole 27 of the cooling block 10 is a pipe 37 which is used as second material supplying means for supplying tritium gas into the hole 34 made in the deuterium block 33. In operation, tritium gas, used as core material, is introduced into the hole 33 of the deuterium block 33, while the hole 31 of the disk 15 remains aligned with the third hole 26. In the hole 34 of the mass 33, the tritium gas solidifies, forming a tritium cylinder 40 which has the same dimensions as the hole 34. From a viewpoint of cryo technology it is easy to cool tritium gas in the hole 34 of the deuterium mass 33. This is because the solidifying highest temperature of tritium is higher than that of deuterium. Movably inserted in the fourth hole 28 of the cooling block 10 is a shaft 41 which is used as pushing means and which can slide horizontally. At least the distal end portion of this shaft 41 has a diameter which is substantially the same as that of the deuterium cylinder 33. As shown in FIG. 1, the cooling block 9 has a hole or cylindrical space 42 which is used as shearing means. The hole 42 is axial aligned with the fourth hole 28 of the cooling block 10. The holes 28 and 42 have substantially the same diameter. They communicate with the hole 31 of the disc 15 as long as the pellet carrier disk 15 takes the position shown in FIG. 1. In operation, the disc 15 is moved until the hole 31 goes into axial alignment with both the fourth hole 28 of the block 10 and the hole 42 of the block 9. Then, the shaft 41 is moved in the direction of the arrow shown in FIG. 5A, pushing the deuterium cylinder 33 for a prescribed distance, e.g., about 1/4 of the thickness of the disk 15. As a result, the deuterium cylinder 33 is located, partly in the hole 31 and partly in the hole 42--with the tritium cylinder 40 positioned at the middle portion of the hole 31 as illustrated in FIG. 5A. The shaft 41 is pulled from the hole 31 in the direction of the arrow shown in FIG. 5B, whereby a space is formed in the hole 31. This space extends horizontally for a distance which is about 1/4 of the thickness of the disc 15. Under this condition, the pellet carrier disk 15 is moved downwards until the hole 31 goes into axial alignment with the fifth hole 29 of the cooling block 10. The cooling block 9 and the moving disc 15 generate a shearing force, which is exerted on the deuterium mass 33. That portion of the cylinder 33 set in the hole 42 is cut from the remaining portion of the cylinder 33, as is seen from from FIG. 6A. Inserted in the fifth hole 29 of the cooling block 10 is a pipe 43 which is used as third material supplying means for supplying deuterium gas into the hole 31 of the pellet carrier disc 15. In operation, deuterium gas is introduced into the hole 31, while the hole 31 remains aligned with the fourth hole 29 as shown in FIG. 6A. In the hole 31, the deuterium gas solidifies, forming a thin tritium cylinder. The thin tritium cylinder is integral with the cylinder 33 and covers the exposed end of the tritium cylinder 40, as is illustrated in FIG. 6B. As a result of this, there is produced a double-layer pellet 45 which consists of the deuterium cylinder 33 (i.e., the outer layer) and the tritium cylinder 40 (i.e., the core) completely embedded in the deuterium cylinder 33. As shown in FIG. 1, one end portion of a high-pressure gas pipe 46 is inserted in the sixth hole 30 of the cooling block 10. The other end portion of the pipe 46 extends through one wall of the the main casing 2 and projects outwards therefrom. The cooling block 9 has a through hole 47 which extends horizontally and which is axially aligned with the sixth hole 30 of the cooling block 10. Inserted in this through hole 47 is one end portion of the pellet-ejecting barrel 48. The other end portion of the barrel 48 extends through one wall of the main casing 2 and projects outwards therefrom. The high-pressure gas pipe 46 and the pellet-ejecting barrel 48 communicate with each other as long as the pellet carrier disc 15 is positioned, with its hole 31 axially aligned with the sixth hole 30 of the cooling block 10. To remove double-layer pellet 45 from the apparatus, the pellet carrier disk 15 is moved until the hole 31 goes into axial alignment with the sixth hole 30 of the cooling block 10. Then, high-pressure gas is supplied onto the pellet 45 through the high-pressure gas pipe 46. The pellet 45 is thereby forced through the pellet-ejecting barrel 48 and finally ejected from the apparatus. The pellet 45 ejected from the apparatus is examined for its shape, its speed and its structure, through an observation window made in a tube connected to the tubular casing 6. The operation of the apparatus shown in FIG. 1 will be explained below. Liquid helium (or low temperature helium gas) used as cooling medium is made to flow into the heat exchangers 7 and 8 via the helium inlet pipes 11 and 13. The cryo section, including the cooling blocks 9 and 10 and the pellet carrier disc 15, is thereby cooled to an extremely low temperature (10 K or less). Next, the pellet carrier disc 15 is set, with the hole 31 axially aligned with the first hole 25 of the cooling block 10 as shown in FIG. 2A. Deuterium gas is introduced into the hole 31 through the pipe 32 and the first hole 25. In the hole 31, the deuterium gas solidifies, forming a deuterium cylinder 33 as shown in FIG. 2B. Thereafter, the pellet carrier disc 15 is moved in the direction of the solid-line arrow (FIG. 2B), bringing the hole 31 into axial alignment with the second hole 26 of the cooling block 10. The shaft 35 is thrust in the direction of the arrow (FIG. 3A) until its distal end portion plunges into the deuterium cylinder 33 as shown in FIG. 3A. Then, as shown in FIG. 3B, the shaft 35 is pulled in the direction of the arrow, forming a hole 34 in the deuterium cylinder 33. Furthermore, the pellet carrier disc 15 is moved in the direction of the broken-line arrow (FIG. 3B), bringing the hole 31 into axial alignment with the third hole 27. Tritium gas is introduced into the hole 34 of the deuterium cylinder 33 through the pipe 37. The tritium gas solidifies in the hole 34, forming a tritium cylinder 40. Then, the pellet carrier disc 15 is moved downwards, thereby setting the hole 31 in axial alignment with the fourth hole 28 of the cooling block 10 and also with the hole 42 of the cooling block 9. The shaft 41 is moved in the direction of the arrow as shown in FIG. 5A, pushing the deuterium cylinder 33 until an end portion of the cylinder 33 projects from the hole 31 into the hole 42 of the cooling block 9. As a result, the tritium cylinder 40 is positioned almost at the middle portion of the hole 31 as illustrated in FIG. 5A. Next, the shaft 41 is moved in the direction of the solid-line arrow shown in FIG. 5B for a prescribed distance, forming a space in the hole 31 and between the cylinder 33 and the distal end of the shaft 41. Under this condition, the pellet carrier disc 15 is moved in the direction of the broken-line arrow shown in FIG. 5B, until the hole 31 goes into axial alignment with the fifth hole 29 of the cooling block as shown in FIG. 6A. That portion of the deuterium cylinder 33 set in the hole 42 is thereby cut from the remaining portion of the cylinder 33, as is seen from from FIG. 6A. Said portion of the cylinder 33, left in the hole 42 of the cooling block 9, will be heated later, turning into deuterium gas, which will be collected through a passage (not shown) made in the cooling block 9. Then, deuterium gas is introduced into the space formed in the hole 31, through the pipe 43. The deuterium gas solidifies in this space, forming a thin tritium cylinder. The thin tritium cylinder is integral with the cylinder 33 and covers the exposed end of the tritium cylinder 40, as is illustrated in FIG. 6B. As a result of this, there is produced a double-layer pellet 45 which consists of the deuterium cylinder 33 and the tritium cylinder 40 embedded in the deuterium cylinder 33. Thereafter, the pellet carrier disc 15 is moved in the direction of the arrow shown in FIG. 6A setting the hole 31 into axial alignment with the sixth hole 30 of the cooling block 10. A high-speed, high-pressure flow valve (not shown), an electromagnetic solenoid (not shown) the like is driven at a proper time, thereby introducing high-pressure gas onto the pellet 45 through the high-pressure gas pipe 46 in the direction of the arrow shown in FIG. 7A. The pellet 45 is thereby forced through the pellet-ejecting barrel 48 in the direction of the arrow shown in FIG. 7B and is finally ejected from the apparatus. As shown in FIG. 8, the pellet 45 is injected into high-temperature plasma 82 generated in a fusion reactor 81 or the like. First, the outer layer of the pellet 45, i.e., the deuterium cylinder 33 evaporates in the plasma 82, and the resultant deuterium gas spreads, forming a gas region 83. Then, the tritium cylinder 40 evaporates near the central part of the plasma, forming vapor cloud 84, as shown in FIG. 8. In this way, fuel is supplied into the plasma 82. As mentioned above, the the apparatus of FIG. 1 produces a double-layer pellet 45 for use in refueling a D-T type fusion reactor, in the following steps. First, a deuterium cylinder 33 is formed. Next, the shaft 35 is thrust into the cylinder 33, making a hole 34 in one end of the deuterium cylinder 33. Tritium gas is then introduced into the hole 34, forming a tritium cylinder 40 in the hole 34. An end portion of the deuterium cylinder 33 is cut off. Further, deuterium gas is applied onto that end of the deuterium cylinder 33 at which the tritium cylinder 40 is exposed. The deuterium gas solidified, forming a layer completely covering the tritium cylinder 40. Hence, the tritium cylinder 40 is not exposed at all. The diameter and depth of the hole 34 in the deuterium cylinder 33 can be altered merely by using a shaft having a different diameter and by plunging the shaft into the cylinder 33 for a different distance. In the hole 34, tritium gas can be cooled and solidified without fail. As a result, the size of tritium cylinder 40 (i.e., the core of the pellet 45) can be changed, and the position the cylinder 40 takes with respect to the deuterium cylinder 33 (i.e. the outer layer of the pellet 45) can be altered. In other words, the apparatus can manufacture pellets each comprising an outer later and a core which has a desired size and assumes a desired position with respect to the outer layer. When the pellet 45 is injected at a proper speed into the plasma generated in a fusion reactor, deuterium, which is not radioactive material and causes no troubles if discharged and recollected, is supplied into the peripheral portion of the plasma. On the other hand, tritium, which is radioactive material, is supplied into only the central part of the plasma, in which nuclear fusion takes place with high efficiency. The load on the tritium-recollecting system and tritium-separating system of the fusion reactor can be reduced remarkably. Since solidified deuterium is much softer than ordinary substances, it is very easy to make a hole in the deuterium cylinder 33. In addition, since the solidifying point of tritium is higher than that of deuterium, it is very easy to solidify tritium in the hole 34 of the deuterium cylinder 33. Therefore, the pellet 45 having the structure specified above can be manufactured with ease. The apparatus shown in FIG. 1 can manufacture not only the double-layer pellets 45 designed for use in refueling a D-T type fusion reactor, but also double-layer pellets designed for use in refueling a D-3He fusion reactor, each of which comprises an outer layer made of deuterium and a core of liquid helium. To manufacture this type of a double-layer, it suffices to introduce helium gas (not tritium gas) into the hole 34 of the deuterium cylinder 33 though the pipe 37 and the hole 27 of the cooling block 10. In the hole 34, the helium gas is cooled and liquefied, with taking the direction of the machine set-up into consideration, as described below. Furthermore, the apparatus shown in FIG. 1 can manufacture a double-layer pellet which comprises an outer layer made of hydrogen and a core made of deuterium. To manufacture this type of a pellet, it suffices to introduce hydrogen gas (not deuterium gas) into the hole 31 of the disc 15 through the first hole 25 of the cooling block 10, thereby forming a hydrogen cylinder, to make a hole 34 in one end of the hydrogen cylinder, and to introduce deuterium gas (not tritium gas) into the hole 34 through the pipe 37 and the hole 27 of the cooling block 10. In the apparatus of FIG. 1, the pellet carrier disc 15 is moved vertically. Instead, the disc 15 may be positioned horizontally and moved horizontally. In this case, both cooling blocks 9 and 10 are positioned horizontally, too--one contacting the upper surface of the disc 15, and the other contacting the lower surface of the disc 15. A cylinder 33 (i.e., the outer layer of a pellet) of, for example deuterium, is positioned vertically, and a hole 34 is formed in the top of the cylinder and extends vertically. Hence, if liquid helium is filled in the hole 34 to be used as the core, it will not flow out of the hole 34. When a double-layer pellet of any type described above is injected into plasma generated in a fusion reactor or an experimental fusion apparatus, a small number of specific ions can be supplied to a desired part of the plasma to minimize the loss of heated high-energy ions, as is required to accomplish a successful plasma physical experiment or to perform ion cyclotron range of frequency heating method. The apparatus of the present invention can manufacture double-layer pellets which can be used to control plasma, as well. Another apparatus which is the second embodiment of the present invention will be described, with reference to FIG. 9. FIG. 9 shows a pellet carrier disc 50 incorporated in this apparatus. The disc 50 can rotate around a shaft 49 in a gap between two cooling blocks (not shown), while the disc 15 used in the apparatus of FIG. 1 is moved vertically in the gap between the cooling blocks 9 and 10, both made of oxygen-free copper. The pellet carrier disc 50 has a through hole 50a which corresponds to the hole 31 of the pellet carrier disc 15 used in the apparatus of FIG. 1. The hole 50a can be brought to positions A, B, C, D, E and F as the disc 50 is rotated around the shaft 49. The cooling block (not shown) corresponding to the cooling block 10 has six through holes (not shown) at the positions A, B, C, D, E and F (FIG. 9), respectively. These holes correspond to the first to sixth holes 25 to 30 of the cooling block 10. In operation, the pellet carrier disc 50 is rotated around the shaft 49, bringing the hole 50a into axial alignment with the six holes of the cooling block which correspond to the holes 25 to 30, so that a double-layer pellet may be produced in the same way as in the apparatus illustrated in FIG. 1. The apparatus according to the second embodiment of the invention achieves the same advantages as the first embodiment (FIG. 1). In addition, it is advantageous in that, after each pellet has been produced, the hole 50a can be axially aligned with the hole at the position A faster than the hole 31 of the disc 15 is axially aligned with the first hole 25 of the cooling block 10. The second embodiment efficiently operates, particularly the sequence of steps is repeated many times on end to manufacture a number of double-layer pellets. The disc 50 is rotated around a vertical axis. Instead, it may be rotated around a horizontal axis. If this is the case, the first to sixth holes have a horizontal axis each and are arranged in a circle concentric to the horizontal axis, spaced apart from one another by a predetermined distance. An apparatus according to a third embodiment of the invention will be described with reference to FIGS. 10 to 17. This apparatus is designed to manufacture a double-layer pellet whose core is a tiny chip of, for example, lithium and whose outer layer is made of deuterium. The components of the apparatus, which are similar or identical to those of the first embodiment, are designated at the same numerals in FIGS. 10 to 18 as in FIGS. 1 to 9, and will not be described in detail in the following description. As can be understood from FIG. 10 which is a sectional view, the third embodiment is characterized in that the cooling block 10 made of oxygen-free copper has a hole 51 instead of the holes 26 and 27 for introducing deuterium gas and tritium gas, respectively. This hole 51 is used to insert a tiny chip 52 (e.g., a lithium chip) into a deuterium cylinder 33 formed in the hole 31 of the pellet carrier disc 15. (In the first and second embodiments, a tritium cylinder 40 is formed in a hole made in the deuterium cylinder 33.) Slidably provided in the hole 51 is a shaft 53 which is used to insert the tiny chip. To state more precisely, the shaft 53 is supported in a tubular shaft guide 54 which is fitted in the hole 51, and can be moved back and forth through the shaft guide 54. The shaft 53 is a slender rod having a diameter of, for example, 50 to 100 .mu.m. As shown in FIG. 11, the shaft 53 is slidably inserted in a small hole 54a made in the distal portion of the shaft guide 54. The shaft 53 is connected, at its rear end, to a disc 55 which has a larger diameter than that of the shaft 53. The disc 55 is slidably inserted in a large hole 54b made in the proximal portion of the shaft guide 54. The large hole 54b has a diameter larger than that of the shaft 53 and is contiguous with the small hole 54a. Slidably inserted in the large hole 54b of the shaft guide 54 is a disc-pushing rod 56, which can be moved horizontally to push the disc 55, thereby to move the shaft guide 34 forwards. The shaft 53, the shaft guide 54, the disc 55 and the disc-pushing rod 56 constitute means for inserting the tiny chip 52 into the deuterium cylinder 33. The tiny chip 52, to be inserted into the deuterium cylinder 33, is made of, for example, lithium which has the least atomic number of all metals which are solid at normal temperature and which is a very soft metal. The chip 52 is supplied into the distal end of the small hole 54a of the shaft guide 54, by means of a chip-supplying device 61. As shown in FIG. 12, the device 61 comprises foil-holding plates 62 and 63, a pushing shaft 64, and a shaft guide 65. The plates 62 and 63 clamp a lithium foil 68 which is, for example, 50 to 100 .mu.m thick. The foil-holding plate 62 has a through hole 66. The shaft guide 65 is removably inserted, at the distal end, in the hole 66 of the plate 62, and extends horizontally. The shaft guide 65 has an axial hole, in which the pushing shaft 64 is slidably inserted. The foil-holding plate 63 has a through hole 67 which is axially aligned with the hole 66 of the foil-holding plate 62. The shaft guide 54 is removably inserted, at the distal end, in the hole 67 of the plate 63, and extends horizontally. As shown in FIG. 12, the pushing shaft 64 is moved in the direction of the arrow until it pushes a portion of the lithium foil 68, a lithium chip 52, into the distal end of the small hole 54a of the shaft guide 54. Then, the shaft 64 is pulled away from the lithium foil 68, leaving the lithium chip 52 in the distal end of the small hole 54a. Thereafter, the shaft guide 54 and the shaft 53 are pulled from the hole 67 of the foil-holding plate 63, and then inserted into the hole 51 of the cooling block 10. The lithium chip 52 may be replaced by a chip of a hard material. In this case, the foil-holding plates 62 and 63 clamp not the lithium foil 68, but a plate which has many holes filled with chips of that hard material, and the pushing shaft 64 is thrust in the direction of the arrow shown in FIG. 12 to attach the chip to the distal end of the shaft 53. The chip 52 is moved through the hole 51 of the cooling block 10 to be inserted into the deuterium cylinder 33. More specifically, the pellet carrier disc 15 is moved until its through hole 31 is set into axial alignment with the hole 51 of the cooling block 10 as shown in FIG. 13A. Then, the shaft 53 is moved in the direction of the arrow shown in FIG. 13B, for a distance equal to the length of the chip 52. The chip 52 is thereby inserted into the deuterium cylinder 33. The shaft 53 is moved away from the cylinder 33, in the direction of the arrow shown in FIG. 13C, leaving the chip 52 in the deuterium cylinder 33. The same manufacturing steps are performed as in the first embodiment (FIG. 1), until the deuterium cylinder 33 is formed in the hole 31 of the pellet carrier disc 15. Thereafter, the chip 52 is attached to the distal end of the shaft 53. To be more specific, as shown in FIG. 12, the lithium foil 68 is clamped between the foil-holding plates 62 and 63, and the shaft guide 54 is inserted into the hole 67 of the foil-holding plate 63. Further, the pushing shaft 64 is thrust in the direction of the arrow, whereby the chip 52 is attached to the distal end of the shaft 53. After the chip 52 has been attached to the shaft 53, the guide 54 is pulled from the shaft foil-holding plate 63 and inserted into the hole 51 of the cooling block 10. The pellet carrier disc 15 is moved until its hole 31 is set into axial alignment with the hole 51 of the cooling block 10 as illustrated in FIG. 13A. Next, the shaft 53 is moved in the direction of the arrow shown in FIG. 13B, thereby inserting the chip 52 into the deuterium cylinder 33. The shaft 53 is then pulled from the deuterium cylinder 33, in the direction of the arrow shown in FIG. 13C. As a result, the chip 52 is left embedded in one end of the deuterium cylinder 33. Thereafter, the same step is performed in the hole 28 of the cooling block 10, as is performed in the first embodiment and as shown in FIGS. 5A and 5B. In other words, a shaft 41 is moved through the hole 28 in the direction of the arrow shown in FIG. 14A, for a distance, e.g., about half the length of the hole 31, thereby pushing the deuterium cylinder 33 (now containing the chip 52) as shown in FIG. 14B. Then, the shaft 41 is pulled from the hole 31, in the direction of the arrow shown in FIG. 14C. The deuterium cylinder 33 is thereby located with the chip 52 positioned almost at the middle portion of the hole 31 of the pellet carrier disc 15. Then, the same step is performed as is conducted in the first embodiment and as shown in FIGS. 6A and 6B. More precisely, that portion of the deuterium cylinder 33 which protrudes into the hole 42 of the cooling block 9 is cut off as illustrated in FIG. 15A, and deuterium gas is introduced into the hole 31, forming a deuterium layer on the end of the cylinder 33, covering the chip 52. As a result, there is produced a double-layer pellet 71 which consists of the deuterium cylinder 33 and the lithium chip 52 completely embedded in the deuterium cylinder 33. Next, the same step is performed as is carried out in the first embodiment and as shown in FIGS. 7A and 7B. That is, the pellet carrier disc 15 is moved, setting the hole 31 of the disc 15 into axial alignment with the hole 30 of the cooling block 10. High-pressure gas is applied onto the pellet 71 through a high-pressure gas pipe 46 in the direction of the arrow shown in FIG. 16A. The pellet 71 is thereby forced through a pellet-ejecting barrel 48 in the direction of the arrow shown in FIG. 16B and is finally ejected from the apparatus. The double-layer pellet 71 thus manufactured may be used in analyzing transport of plasma particles. As shown in FIG. 17, the pellet 71 is injected into high-temperature plasma 82 generated in a fusion reactor 81 or the like. In the peripheral part of the plasma 82, only the deuterium cylinder 33 (i.e., the outer layer of the pellet 71) evaporates, and the resultant deuterium gas spreads, forming a gas region 83, as has been explained with reference to FIG. 8. When the deuterium cylinder 33 evaporates in its entirety, the chip 52 (i.e., the core of the pellet 71) evaporates near the central part of the plasma 82, forming vapor cloud 91. Some time later, the vapor could 91 is ionized. In initial stage, specific particles move around a torus 85 (only a part shown) along magnetic field lines, in the directions of the arrows 86 (that is, substantially in toroidal direction). The flux of these specific particles is charge-exchanged with a plurality of neutron beams 93 under examination. A charge-exchanged recombinant light, bremsstrahlung radiation or soft X rays is observed thorough a plurality of channels. The particles being transported in parallel to the lines of magnetic force can thereby be analyzed. As time passes, the specific particles are filled in an annular magnetic surface (or a group of magnetic surfaces) 96. The particles start moving in the direction perpendicular to the magnetic field lines; they diffuse in the direction of the arrow 97. This behavior of the specific particles is observed by the same method as described above, thereby analyzing the plasma particles being transported in a direction perpendicular to the magnetic field lines. If the chip 52 has an appropriate size, it will be possible to supply specific particles which differ from the particles constituting plasma confined in a space as small as in the range of 1 cm.sup.3. Of the specific particles, some move in parallel to the plasma-confining magnetic field lines, and the others move at right angles to the lines of magnetic force. The motion of these specific particles are observed to efficiently analyze the transport of the particles. In the apparatus (FIG. 10) according to the third embodiment, a deuterium cylinder 33 is first formed to serve as the outer layer of a pellet for use in analyzing the transport of plasma particles. Next, a chip 52 is embedded into one end of the deuterium cylinder 33 by using the shaft 53. Then, the other end of the deuterium cylinder 33 is cut off. Finally, deuterium gas is applied onto the first-mentioned end of the cylinder 33 and cooled and solidified, forming a double-layer pellet 71. The core of the pellet 71, i.e., chip 52, is completely embedded in the outer layer, i.e., the deuterium cylinder; it is not exposed at all. Since the chip 52 is inserted directly into the deuterium cylinder 33, its size can be freely changed. Therefore, the cores and the outer layer can have desired sizes and can take a predetermined positional relationship. Since solidified deuterium is much softer than ordinary substances, it is very easy to insert the chip 52 into the deuterium cylinder 33. It follows that the double-layer pellet 71 can be easily manufactured. Like the pellet 45 described above, the double-layer pellet 71 can be used not only in refueling a fusion reactor, but also in supplying specific ions, in no excess numbers, to accomplish a successful plasma physical experiment or to perform ion cyclotron range of frequency heating method. Specific particles, which differ from the particles constituting plasma, can be supplied to a limited part of the plasma by injecting the double-layer pellet 71 into the plasma. The absolute number of particles supplied into the plasma can therefore be determined with very high accuracy. The specific particles supplied move in parallel to lines of magnetic force (=magnetic field lines), and are observed to analyze the plasma particles being transported in parallel to the lines of magnetic force. The specific particles starts moving in an annular magnetic surface (or a group of magnetic surfaces), at right angles to the lines of magnetic force. This behavior of the specific particles is observed and examined, thereby to analyze the plasma particles being transported in a direction perpendicular to the lines of magnetic force. Furthermore, the speed with which the pellet 71 is injected into the plasma can be changed in order to change the position in the plasma to which the specific particles are to be applied. In this sense, the use of the pellet 71 helps enhance the flexibility of the particle transport analysis. An apparatus according to a fourth embodiment of the invention will be described with reference to FIG. 18 which shows the pellet carrier disc 73 incorporated in this apparatus. As can be understood from FIG. 18, the apparatus is characterized in that the disc 73 is rotated around a shaft 72, not moved vertically in the gap between the cooling blocks (not shown) as in the third embodiment shown in FIG. 10. The pellet carrier disc 73 has a through hole 73a which corresponds to the hole 31 of the pellet carrier disc 15 used in the apparatus of FIG. 1. The hole 73a can be brought to positions G, H, I, J and K as the disc 72 is rotated around the shaft 72. The cooling block (not shown) corresponding to the cooling block 10 has five through holes (not shown) at the positions G, H, I, J, and K, respectively. These holes correspond to the first to the holes 25, 51, 28, 29 and 30 of the cooling block 10. In operation the disc 73 is rotated to set the hole 73a into axial alignment with the five holes of the cooling block, one after another. In the five holes of the cooling block, there are performed the manufacturing steps identical to those carried out in the holes 25, 51, 28, 29 and 30 of the cooling block 10. Therefore, the apparatus according to the fourth embodiment of the invention achieves the same advantages as the third embodiment (FIG. 10). It is advantageous also in that, after each pellet has been produced, the hole 73a can be axially aligned with the hole at the position G faster than the hole 31 of the disc 15 is axially aligned with the first hole 25 of the cooling block 10. The fourth embodiment efficiently operates, particularly the sequence of steps is repeated many times on end to manufacture a number of double-layer pellets. As has been described above in detail, the present invention can provide a method and apparatus which can easily manufacture double-layer pellets whose cores and outer layers can be controlled in their size and their positional relationship, whose cores can be formed without fail, and which can therefore serve to supply fuel into a desired part of plasma in no excess amount. The present invention can also provide a method and apparatus which can easily manufacture double-layer pellets whose cores are made of chips and whose cores and outer layers can be controlled in their sizes and their positional relationship, which serve to analyze transport of particles and heat in a fusion reactor and, hence, to inject particles to be observed, in no excess numbers, into a desired part of plasma. Still further, the present invention can provide a method and apparatus which can easily manufacture double-layer pellets which serve to efficiently perform ion cyclotron range of frequency heating. Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details, representative devices, and illustrated examples shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.
	description	As shown in FIG. 1, a nuclear power station conventionally includes a reactor pressure vessel 10 with various configurations of fuel and reactor internals for producing nuclear power. For example, vessel 10 may include a core shroud 30 surrounding a nuclear fuel core 35 that houses fuel structures, such as fuel assemblies, 40. A top guide 45 and a fuel support 70 may support each fuel assembly 40. An annular downcorner region 25 may be formed between core shroud 30 and vessel 10, through which fluid coolant and moderator flows into the core lower plenum 55. For example, in US Light Water Reactor types, the fluid may be purified water, while in natural uranium type reactors, the fluid may be purified heavy water. In gas-cooled reactors, the fluid coolant may be a gas such as helium, with moderation provided by other structures. The fluid may flow upward from core lower plenum 55 through core 35. After being heated in core 35, the energetic fluid may enter core upper plenum 60 under shroud head 65. One or more control rod drives 81 may be positioned below vessel 10 and connect to control rod blades 80 (FIG. 2) that extend among fuel assemblies 40 within core 35. Vessel 10 may be sealed and opened through upper head 95 at flange 90. With access to the reactor internals, some of fuel bundle assemblies 40 are replaced and/or moved within core 35, and maintenance / installation on other internal structures and external structures, including shroud 30 and reactor pressure vessel 10 itself may be performed inside and outside reactor 10. FIG. 2 is an illustration of a portion of fuel core 35 from FIG. 1 showing several fuel assemblies 40 positioned about a control blade 80. During operation, control rod drive 81 maneuvers control rod blade 80 to a desired axial position among fuel assemblies 40 to obtain a desired power density. Control rod blade 80 typically has a cross or cruciform traverse cross-section; however, rods and other shapes are known control elements useable in nuclear reactors. Control rod blade 80 includes a material that absorbs neutrons of a desired spectrum, such as boron, cadmium, etc., so as to reduce neutron fluence among assemblies 40 and thus control the nuclear chain reaction. In FIG. 2, fuel bundle assemblies 40 surround the control rod blade 80, which is positioned in a central intersection surrounded by the four fuel bundle assemblies 40 in order to maximize exposure to, and thus control, fuel assemblies 40 together. FIG. 3 is an illustration of a related art fuel assembly 40, such as assemblies 40 shown in FIGS. 2 and 3. As shown in FIG. 3, fuel assembly 40 includes multiple fuel rods 14 filled with fissile material for power generation. Fuel rods 14 are arranged in a uniform grid laterally and extend in the axial direction continuously throughout assembly 40. Fuel rods 14 are seated into a lower tie plate 16 and extend upward into an upper tie plate 17 at ends of fuel assembly 40. Fuel rods 14 are bounded by a channel 12 that forms an exterior of the assembly 40, maintaining fluid flow within assembly 40 throughout the axial length of assembly 40. Conventional fuel assembly 40 also includes one or more fuel spacers 18 at various axial positions to align and space fuel rods 14. One or more water rods 19 may also be present to provide a desired level of moderator or coolant through-flow to assembly 40. Example embodiments include nuclear fuel cores and surrounding structures, fuel assemblies for use in the same, and fluence control structures for use in the same. Example cores include nuclear fuel assemblies in combination with a fuel assembly/ies having a fluence control structure(s). Fluence-limiting assemblies and structures may be positioned outside of or around the other nuclear fuel assemblies in the core so as to reduce neutron flux beyond the fluence controlled nuclear fuel assemblies. The fluence control structure may itself be positioned at an outside edge of the core so that fluence control exists only beyond the nuclear fuel assemblies and fluence-limiting assemblies. Fluence control structures limit neutron flux at particular positions through the use of appropriate material, dimensioning, and placement in fuel assemblies. In example methods, core engineers may select and/or install fluence-limiting fuel assemblies with flux-limiting characteristics in cores having neutronics profiles expected to benefit from such flux limitation. This is a patent document, and general broad rules of construction should be applied when reading and understanding it. Everything described and shown in this document is an example of subject matter falling within the scope of the appended claims. Any specific structural and functional details disclosed herein are merely for purposes of describing how to make and use example embodiments or methods. Several different embodiments not specifically disclosed herein fall within the claim scope; as such, the claims may be embodied in many alternate forms and should not be construed as limited to only example embodiments set forth herein. It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. It will be understood that when an element is referred to as being “connected,” “coupled,” “mated,” “attached,” or “fixed” to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between”, “adjacent” versus “directly adjacent”, etc.). Similarly, a term such as “communicatively connected” includes all variations of information exchange routes between two devices, including intermediary devices, networks, etc., connected wirelessly or not. As used herein, the singular forms “a”, “an” and “the” are intended to include both the singular and plural forms, unless the language explicitly indicates otherwise with words like “only,” “single,” and/or “one.” It will be further understood that the terms “comprises”, “comprising,”, “includes” and/or “including”, when used herein, specify the presence of stated features, steps, operations, elements, ideas, and/or components, but do not themselves preclude the presence or addition of one or more other features, steps, operations, elements, components, ideas, and/or groups thereof. It should also be noted that the structures and operations discussed below may occur out of the order described and/or noted in the figures. For example, two operations and/or figures shown in succession may in fact be executed concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved. Similarly, individual operations within example methods described below may be executed repetitively, individually or sequentially, so as to provide looping or other series of operations aside from the single operations described below. It should be presumed that any embodiment having features and functionality described below, in any workable combination, falls within the scope of example embodiments. The inventor has recognized problems arising from nuclear power operations where neutron flux over time, or fluence, causes component brittling and/or failure. This problem may have particular consequences on especially flux-sensitive, or large, non-replaceable nuclear components such as a core shroud 30 (FIG. 1) or reactor pressure vessel 10 (FIG. 1). The inventor has further discovered that installation of a separate reflector/absorber structure inside of a reactor or use of smaller cores with water perimeters create additional problems. A separate reflector/absorber structure requires its own separate installation and maintenance and may not fit between a core and a shroud without interfering with hydrodynamics. Smaller cores generate less power and can have sharper radial flux profiles, which can near or exceed safety margins for power ratios of fuel assemblies. The below disclosure uniquely overcomes these and other problems recognized by the inventor in nuclear reactor operations. The present invention is nuclear fuel-based fluence control. Example embodiments discussed below illustrate just a subset of the variety of different configurations that can be used as and/or in connection with the present invention. FIG. 4 is a quadrant map of an example embodiment reactor core having example embodiment peripheral fuel assembly fluence control structures. In FIG. 4, each square represents a fuel assembly location within one quarter of the core. Reactor cores can be symmetrical about at least two perpendicular axes, such that a quadrant map like FIG. 4 can convey a makeup of the entire core. Although FIG. 4 illustrates a 17×17 quadrant found in some Boiling Water Reactor designs, other core sizes and shapes are useable with example embodiments. As shown in FIG. 4, locations may be filled (solid outline) and empty (dashed outline) to create a core and perimeter beyond which a shroud and/or reactor vessel (e.g., shroud 30 and/or vessel 10 from FIG. 1) may bound the core. Occupied assembly locations may accommodate higher (diagonal or cross-hatched fill) or lower (shown with no fill) reactivity fuel bundles during any fuel cycle. Varying reactivity can be achieved through varying initial fuel enrichments, using fuel assemblies of different exposures, adjusting fission poisons, etc. For example, the ring of lower enrichment assemblies about an outer perimeter shown in FIG. 4 may be lower enrichment assemblies using natural uranium or once-burnt assemblies, and higher enrichment bundles in an interior portion of the core may use enriched uranium or fresher bundles. Other reactivity patterns, including cores with uniform reactivity, are useable as example embodiment cores. Control elements, such as control rod blades 80 (FIG. 2), are positioned throughout an interior of the core. A subset of such control elements may be used during operation to control power in the core, and assemblies adjacent to control elements regularly moved to adjust reactivity are shown as controlled bundles in FIG. 4, outlined in heavier squares containing four assembly locations. For example, as shown in FIG. 2, assemblies 10 positioned about a control blade 80 may be represented as controlled assemblies in FIG. 4. Although not shown in FIG. 4, other control elements and controlled assembly groups may be used with example embodiments, including control elements and controlled assemblies closer to a core periphery. As such, it is understood that the shape, size, assembly pattern, control element pattern, and assembly reactivity levels of the example embodiment core may be varied across known and future designs, based on requirements for power generation, safety margins, reactor type, etc. As shown in FIG. 4, fuel assembly fluence control structures are used in fuel assemblies about an outermost perimeter of the example embodiment fuel core. Fluence control structures are shown by heaviest outlining in FIG. 4. Example embodiment fluence control structures do not generate flux but have a substantial absorptive and/or reflective effect on neutron flux for the spectra encountered at a periphery of a fuel assembly. For example, fluence control structures may include materials having absorption cross sections of one barn or more for thermal and fast neutrons. In this way, fluence control structures limit neutron flux—and thus fluence over time—beyond the core. As shown in FIG. 4, fuel assembly fluence control structures may be used on one or more outside edges of peripheral fuel assemblies such that fluence control may be continuous on and exclusive to the core periphery, creating a flux boundary at an entire outer perimeter of the core. This may reduce fluence to a core shroud, reactor pressure vessel, and/or other reactor internals surrounding the core. Fluence control structures may extend axially completely through the core or at selected elevations. Similarly, fuel assembly fluence control structures may be selectively used on less than all peripheral fuel assembly surfaces to create broken peripheral positions that shield only particular locations. For example, only corner assemblies, such as the assembly at position 12-2 in FIG. 4, having two exposed surfaces may use fuel assembly fluence control structures, while assemblies with less exposure lack such structures, or fuel assembly fluence control structures may be used only at locations with significant fluence impact on vulnerable components. Fluence control structures may further be used at internal positions within the periphery for assembly manufacturing simplicity, flux shaping, and/or shielding of components internal to the core, for example. Example embodiment fuel assembly fluence control structures may be components of fuel assemblies or otherwise directly attached in example embodiment fuel assemblies. In this way, fluence control may be positioned based on fuel assembly positioning. As shown in FIG. 4, by selectively placing and orienting fuel assemblies with one or two faces of example embodiment fluence control structures with a shared axial positioning, a continuous perimeter of fluence control can be formed about a core exterior perimeter across the entire core elevation or at specific axial sections. By installing fluence control structures in individual fuel assemblies, fluence control positions may be created, altered, and/or removed by moving or reorienting fuel assemblies appropriately, without the need for additional installation in or near a reactor core. Example embodiment fuel assembly fluence control structures may have a variety of forms and characteristics. For example, fluence control structures may be positioned at a variety of locations about core structures and fuel assemblies to provide shielding at desired locations. Similarly, fluence control structures may be fabricated of a variety of flux-limiting materials to provide a desired amount of shielding where placed. Multiple different fluence control structures are useable together in any combination and at any position based on neutronics characteristics in the core and desired fluence limitation. FIG. 5 is an illustration of an example embodiment fluence control structure in use with an example embodiment fuel assembly 110. Although FIG. 5 illustrates multiple different example embodiment fluence control structures, it is understood that any individual aspect of FIG. 5 can be used alone or in any combination. Example embodiment fuel assembly 110 may be very similarly configured to, and used interchangeably with, conventional fuel assemblies, such as fuel assembly 10 in FIGS. 1-3. Use of example embodiment fluence control structure(s) in example embodiment assemblies does not necessarily reduce or destroy compatibility with a variety of different reactor types. For example, as shown in FIG. 5, example embodiment fuel assembly 110 may be used in a position adjacent to a control blade 80 and house conventional elements like fuel rods 14, both full (“T”) and part-length (“P”), and water rods 19, just as, and in place of, a conventional BWR fuel assembly. Example embodiment fuel assembly 110 includes plate curtain 120 as a fluence control structure. Plate curtain 120 may be on an interior or exterior of channel 112, attached by welding, bolting, formed as an integral piece with channel 112, and/or with any other joining mechanism. For example, two plate curtains 120 may be placed on either the outside or inside of the outermost faces of channel 112 exposed to a core shroud or reactor pressure vessel, if fuel assembly 110 is a corner assembly such as position 6-6 in FIG. 4. Plate curtain 120 can extend completely or substantially about an interior or exterior face of assembly 110, or plate curtain 110 may cover only a lateral or axial portion of a channel face in assembly 110. The placement and size of plate curtain 120 may be selected based on its flux reducing properties and position within a core. For example, neutron flux at a particular core position may be projected to be especially high except at lower axial positions, and plate curtain 120 may extend only about channel 112 to cover the upper axial portions. Plate curtain 120 is fabricated of a material and thickness having a desired neutron flux reduction characteristic. For example, plate curtain 120 may be stainless steel, having a higher neutron absorption cross section at reactor energies, or zirconium, having a lower neutron absorption cross section. For an even stronger effect, plate curtain 120 may be fabricated similarly as an arm of a cruciform control blade 80 and contain a stronger neutron absorber like hafnium, boron, gadolinium, cadmium, etc. Plate curtain 120 may be of any thickness that does not interfere with other core structures, including about 65-200 mil (thousands of an inch). Similarly to determining position and coverage for plate curtain 120, material and thickness of plate curtain 120 can be selected based on expected neutronics and flux reduction. For example, if lower enrichment bundles are used about a periphery of a core as shown in FIG. 4, plate curtains 120 may be thinner and use a lower absorption material like a zirconium alloy. In other situations with higher thermal and/or fast fluxes, a control-blade style plate curtain 120 may be used. As such, plate curtains 120 of appropriate material and thickness will absorb and/or reflect neutron flux from a perimeter of a core and prevent or reduce fluence over time to structures outside of plate curtains 120, such as a core shroud or reactor vessel, in example embodiment assembly 110. Example embodiment fuel assembly 110 includes a shielding channel 112 as a fluence control structure. Shielding channel 112 may be identical to a conventional channel 12 (FIGS. 1-3) in shape and size. Of course, in other fuel designs, shielding channel 112 may take on other shapes, sizes, alignments, and connection points in order to preserve such compatibility across several other types of fuel and reactors. Shielding channel 112 may be fabricated of a material with a higher or desired absorption and/or scattering cross section for neutron fluxes expected to be encountered at a position of example embodiment fuel assembly 110. For example, shielding channel 112 may be fabricated from stainless steel instead of a zirconium alloy, or shielding channel 112 may be doped with materials like boron and hafnium that limit neutron flux. Shielding channel 112 may be fabricated in a composite fashion with only select sides/edges having a neutron-flux-reducing material, or shielding channel 112 may be fabricated of a uniform material. Shielding channel 112 may have a lower effect on reducing neutron flux in example embodiment assembly 110, due to the relative thinness of shielding channel 112. Thus, even if fabricated of a uniform material for manufacturing simplicity, shielding channel 112 will not have a substantially detrimental effect on flux inside of a core, where flux is desired. Shielding channel 112 fabricated with appropriate neutron absorber or reflector will also reduce neutron flux from a perimeter of a core and prevent or reduce fluence over time to structures outside of example embodiment fuel assembly 110, such as a core shroud or reactor vessel, when used in assemblies near such structures. Example embodiment fuel assembly 110 includes a shielding fuel rod 114 as a fluence control structure. As shown in FIG. 5, shielding fuel rods 114 may occupy an outer row and/or column closest to an edge of a core if example embodiment fuel assembly 110 is placed at a corner or outer position. An entire outer row and outer column in assembly 110 may be made up of only shielding fuel rods 114, or shielding fuel rods 114 may be placed at intervals or in other patterns or positions throughout assembly 110 that limit flux in a desired way. Shielding fuel rods 114 are compatible with, and may replace, conventional fuel rods 14, both full length T and part length P, which shielding rods 114 may match in diameter, length, and/or outer cladding characteristics. Of course, in other fuel designs, shielding rods 114 may take on other shapes, sizes, alignments, densities, and connection points in order to preserve such compatibility across several other types of fuel and reactors. Shielding fuel rods 114 reduce neutron flux of expected energies through absorption and/or scattering at their location within the example embodiment fuel assembly 110. Shielding fuel rods 114 may take on a variety of configurations based on the amount and type of flux-reducing effect desired. For example, shielding fuel rods 114 may be an empty zirconium cladding tube, that is, a fuel rod with no fuel pellets, or an empty stainless steel or other metal cladding tube. Or shielding fuel rod 114 may be a solid zirconium alloy, stainless steel, or other metal rod with no hollow interior or with dummy pellets of the chosen material inserted therein. These examples removing fuel elements and/or using higher absorption and/or thicker materials have a modest effect on neutron flux, with materials having higher cross-sections having greater reduction of flux and fluence over time. Still further, shielding fuel rods 114 may include even higher cross-section materials, including fission poisons and other flux reducers like boron, gadolinium, cadmium, hafnium, etc., for greater flux reduction. Shielding fuel rods 114 may also include irradiation targets like cobalt-59 or iridium that produce desired isotopes as they absorb flux. For example, shielding fuel rods 114 may be segmented rods as disclosed in co-owned US Patent Publications 2007/0133731 to Fawcett et al., 2009/0122946 to Fawcett et al., 2009/0135983 to Russell, II et al., 2009/0135988 to Russell, II et al., 2009/0135990 to Fung Poon et al., and/or 2013/0077725 to Bloomquist et al., the disclosures of these publications being incorporated herein in their entireties. In the example of a segmented fuel rod for shielding fuel rods 114, axial variation in flux absorption and/or reflecting may be achieved by filling different axial segments with different materials having desired cross sections for a particular axial level. Shielding fuel rods 114 may thus reduce flux escaping beyond example embodiment fuel assembly 110 while producing desired isotopes for harvesting and/or having a burnable poison effect where flux reduction may vary through a single fuel cycle. Although example embodiment fuel assembly 110 of FIG. 5 is illustrated with fluence control structures like shielding fuel rods 114, shielding channel 112, and/or plate curtain 120, it is understood that other and any fluence control structures are useable with example embodiment fuel assemblies. Additionally, fluence control structures can be used alone, in multiples, or in any combination, depending on the shielding needs at a core location where example embodiment fuel assemblies may be placed. For example, in the example core of FIG. 4 with an outer ring of lower reactivity fuel assemblies to permit a flatter radial power profile while reducing neutron flux at core edges, an assembly at position 5-9 (column-row) may have only a single face exposed outside the core and be surrounded by lower-power assemblies. Such an example embodiment 5-9 fuel assembly may use only a single plate curtain 120 on the exposed face fabricated of stainless steel only 60 mils thick or use only a shielding channel 112 doped with a neutron absorber and satisfactorily reduce fluence to reactor structures adjacent to the 5-9 position. These example fluence control structures may be relatively simple to implement from a manufacturing and operational standpoint. Or, for example, an example embodiment fuel assembly may be placed at a core position adjacent to a flux-sensitive component, such as a reactor core shroud that has been in use for decades and is nearing lifetime maximum fluence constraints. In such an example embodiment fuel assembly, multiple fluence control structures with high flux reduction capacity may be used together. For example, in a corner fuel assembly, a complete, outermost row and column of fuel rods may be shielding fuel rods 114 fabricated of solid stainless steel. In combination, a control-blade-arm type plate curtain 120 having very high neutron-absorption may be installed on exterior faces of the assembly nearest the shroud. This example fluence control structure combination may have very high flux-stopping capacity and shield the flux-sensitive component without the installation of separate reactor internal structures. Of course, any number of other combinations of fluence control structures are useable in example embodiment fuel assemblies, based on fluence-limiting needs at any radial or axial position inside the reactor and operating concerns like manufacturing simplicity, fuel costs, reactor type, core makeup and neutronic response, isotope production needs, and core and fuel dimensions. A reactor engineer can forecast the core needs and flux response for a particular cycle and may choose and position example embodiment fuel assemblies accordingly for use in upcoming operations. Example embodiments and methods thus being described, it will be appreciated by one skilled in the art that example embodiments may be varied and substituted through routine experimentation while still falling within the scope of the following claims. For example, a variety of different reactor and core designs are compatible with example embodiments and methods simply through proper dimensioning of example embodiments—and fall within the scope of the claims. Such variations are not to be regarded as departure from the scope of these claims.
	description	This application is a divisional of U.S. application Ser. No. 16/100,352, filed Aug. 10, 2018, which claims priority to Korean Patent Application No. 10-2017-0101869, filed in the Korean Intellectual Property Office on Aug. 10, 2017, and all the benefits accruing therefrom under 35 U.S.C. § 119, the contents of each of which are incorporated herein in entirety by reference. Example embodiments relate to a compound and an organic photoelectric device, an image sensor, and/or an electronic device including the same. A photoelectric device may convert light into an electrical signal using photoelectric effects. A photoelectric device may include a photodiode, a phototransistor, etc., and may be applied to an image sensor, etc. An image sensor including a photodiode may require high resolution and thus a small pixel. At present, a silicon photodiode is widely used. In some cases, a silicon photodiode exhibits a problem of deteriorated sensitivity because of a relatively small absorption area due to relatively small pixels. Accordingly, an organic material that is capable of replacing silicon has been researched. An organic material may have a relatively high extinction coefficient and may selectively absorb light in a particular wavelength region depending on a molecular structure, and thus may simultaneously replace a photodiode and a color filter and resultantly improve sensitivity and contribute to relatively high integration. Example embodiments provide a compound capable of selectively absorbing light in a green wavelength region and having improved deposition stability, heat resistance, and oxidation resistance. Example embodiments also provide an organic photoelectric device capable of selectively absorbing light in a green wavelength region and improving efficiency. Example embodiments also provide an image sensor including the organic photoelectric device. Example embodiments also provide an electronic device including the image sensor. According to example embodiments, a compound represented by Chemical Formula 1 is provided. In Chemical Formula 1, X1 may be one of S, Se, Te, O, S(═O), S(═O)2, NRa1, SiRb1Rc1, or GeRd1Re1 (wherein Ra1, Rb1, Rc1, Rd1, and Re1 independently may be one of hydrogen, a substituted C1 to C10 alkyl group, or an unsubstituted C1 to C10 alkyl group), Ar may be an aromatic ring group including N and X2 (wherein X2 may be one of S, Se, Te, O, S(═O), S(═O)2, N, NRa2, CRb2, CRc2Rd2, SiRe2Rf2, or GeRg2Rh2, and Ra2, Rb2, Rc2, Rd2, Re2, Rf2, Rg2, and Rh2 independently may be one of hydrogen, a substituted C1 to C10 alkyl group, or an unsubstituted C1 to C10 alkyl group), R1 to R3 independently may be one of hydrogen, deuterium, a substituted C1 to C30 alkyl group, an unsubstituted C1 to C30 alkyl group, a substituted C1 to C30 alkoxy group, an unsubstituted C1 to C30 alkoxy group, a substituted C6 to C30 aryl group, an unsubstituted C6 to C30 aryl group, a substituted C3 to C30 heteroaryl group, an unsubstituted C3 to C30 heteroaryl group, a substituted C2 to C30 acyl group, an unsubstituted C2 to C30 acyl group, a halogen, a cyano group (—CN), a cyano-containing group, a nitro group, —SiRaRbRc (wherein Ra, Rb, and Rc independently may be one of hydrogen, a substituted C1 to C10 alkyl group, or an unsubstituted C1 to C10 alkyl group), or a combination thereof, and Y may be a functional group represented by Chemical Formula 2A or Chemical Formula 2B. In Chemical Formula 2A, Ar1 and Ar2 independently may be one of a substituted C6 to C30 aryl group, an unsubstituted C6 to C30 aryl group, a substituted C3 to C30 heteroaryl group or an unsubstituted C3 to C30 heteroaryl group. In Chemical Formula 2B, Ar3 and Ar4 independently may be one of a substituted C6 to C30 arylene group, an unsubstituted C6 to C30 arylene group, a substituted C3 to C30 heteroarylene group or unsubstituted C3 to C30 heteroarylene group, and G may be one of a single bond, S, Se, Te, O, NRa3, (CRb3Rc3)n, (C(Rd3)═C(Re3)), SiRf3Rg3, or GeRh3Ri3 (wherein Ra3, Rb3, Rc3, Rd3, Re3, Rf3, Rg3, Rh3, and Ri3 independently may be one of hydrogen, a halogen, a substituted C1 to C10 alkyl group, an unsubstituted C1 to C10 alkyl group, a substituted C6 to C10 aryl group, or an unsubstituted C6 to C10 aryl group, and optionally Rd3 and Re3 independently may be present or may be linked with each other to provide a fused ring, and n may be an integer of 1 or 2). In some example embodiments, in Chemical Formula 1, Ar may be represented by one of the structures in Chemical Formula 3A to Chemical Formula 3E. In Chemical Formula 3A, X2a may be one of S, Se, Te, O, S(═O), S(═O)2, NRa2, CRc2Rd2, SiRe2Rf2, or GeRg2Rh2 (wherein, Ra2, Rc2, Rd2, Re2, Rf2, Rg2, and Rh2 independently may be one of hydrogen, a substituted C1 to C10 alkyl group, or an unsubstituted C1 to C10 alkyl group), R11 to R16 independently may be one of hydrogen, deuterium, a substituted C1 to C30 alkyl group, an unsubstituted C1 to C30 alkyl group, a substituted C1 to C30 alkoxy group, an unsubstituted C1 to C30 alkoxy group, a substituted C6 to C30 aryl group, an unsubstituted C6 to C30 aryl group, a substituted C3 to C30 heteroaryl group, an unsubstituted C3 to C30 heteroaryl group, a substituted C2 to C30 acyl group, an unsubstituted C2 to C30 acyl group, a halogen, a cyano group (—CN), a cyano-containing group, a nitro group, —SiRaRbRc (wherein Ra, Rb, and Rc independently may be one of hydrogen, a substituted C1 to C10 alkyl group, or an unsubstituted C1 to C10 alkyl group), or a combination thereof, wherein R11 to R16 independently may be present or an adjacent two thereof may be linked with each other to provide a fused ring. In Chemical Formula 3B, X2b may be one of N or CRb2 (wherein, Rb2 may be one of hydrogen, a substituted C1 to C10 alkyl group, or an unsubstituted C1 to C10 alkyl group), and R11 to R17 independently may be one of hydrogen, deuterium, a substituted C1 to C30 alkyl group, an unsubstituted C1 to C30 alkyl group, a substituted C1 to C30 alkoxy group, an unsubstituted C1 to C30 alkoxy group, a substituted C6 to C30 aryl group, an unsubstituted C6 to C30 aryl group, a substituted C3 to C30 heteroaryl group, an unsubstituted C3 to C30 heteroaryl group, a substituted C2 to C30 acyl group, an unsubstituted C2 to C30 acyl group, a halogen, a cyano group (—CN), a cyano-containing group, a nitro group, —SiRaRbRc (wherein Ra, Rb, and Rc independently may be one of hydrogen, a substituted C1 to C10 alkyl group, or an unsubstituted C1 to C10 alkyl group), or a combination thereof, wherein R11 to R17 and Rb2 independently may be present or an adjacent two thereof may be linked with each other to provide a fused ring. In Chemical Formula 3C, X2b may be one of N or CRb2 (wherein, Rb2 may be one of hydrogen, a substituted C1 to C10 alkyl group, or an unsubstituted C1 to C10 alkyl group), R11 to R17 independently may be one of hydrogen, deuterium, a substituted C1 to C30 alkyl group, an unsubstituted C1 to C30 alkyl group, a substituted C1 to C30 alkoxy group, or an unsubstituted C1 to C30 alkoxy group, a substituted C6 to C30 aryl group, an unsubstituted C6 to C30 aryl group, a substituted C3 to C30 heteroaryl group, an unsubstituted C3 to C30 heteroaryl group, a substituted C2 to C30 acyl group, an unsubstituted C2 to C30 acyl group, a halogen, a cyano group (—CN), a cyano-containing group, a nitro group, —SiRaRbRc (wherein Ra, Rb, and Rc independently may be one of hydrogen, a substituted C1 to C10 alkyl group, or an unsubstituted C1 to C10 alkyl group), or a combination thereof, wherein R11 to R17 and Rb2 independently may be present or an adjacent two thereof may be linked with each other to provide a fused ring. In Chemical Formula 3D, X2b may be one of N or CRb2 (wherein, Rb2 may be one of hydrogen, a substituted C1 to C10 alkyl group, or an unsubstituted C1 to C10 alkyl group), and R11 to R17 independently may be one of hydrogen, deuterium, a substituted C1 to C30 alkyl group, an unsubstituted C1 to C30 alkyl group, a substituted C1 to C30 alkoxy group, an unsubstituted C1 to C30 alkoxy group, a substituted C6 to C30 aryl group, an unsubstituted C6 to C30 aryl group, a substituted C3 to C30 heteroaryl group, an unsubstituted C3 to C30 heteroaryl group, a substituted C2 to C30 acyl group, an unsubstituted C2 to C30 acyl group, a halogen, a cyano group (—CN), a cyano-containing group, a nitro group, —SiRaRbRc (wherein Ra, Rb, and Rc independently may be one of hydrogen, a substituted C1 to C10 alkyl group, or an unsubstituted C1 to C10 alkyl group), or a combination thereof, wherein R11 to R17 and Rb2 independently may be present or an adjacent two thereof may be linked with each other to provide a fused ring. In Chemical Formula 3E, R11 and R12 independently may be one of hydrogen, deuterium, a substituted C1 to C30 alkyl group, an unsubstituted C1 to C30 alkyl group, a substituted C1 to C30 alkoxy group, an unsubstituted C1 to C30 alkoxy group, a substituted C6 to C30 aryl group, an unsubstituted C6 to C30 aryl group, a substituted C3 to C30 heteroaryl group, an unsubstituted C3 to C30 heteroaryl group, a substituted C2 to C30 acyl group, an unsubstituted C2 to C30 acyl group, a halogen, a cyano group (—CN), a cyano-containing group, a nitro group, —SiRaRbRc (wherein Ra, Rb, and Rc independently may be one of hydrogen, a substituted C1 to C10 alkyl group, or an unsubstituted C1 to C10 alkyl group), or a combination thereof. In some example embodiments, Chemical Formula 2A, at least one of Ar1 and Ar2 may include a heteroatom selected from nitrogen (N), sulfur (S), and selenium (Se). In some example embodiments, Chemical Formula 2B, at least one of Ar3 and Ar4 may include a heteroatom selected from nitrogen (N), sulfur (S), and selenium (Se). In some example embodiments, Chemical Formula 1, Y may be a functional group represented by one of Chemical Formula 2A-1, Chemical Formula 2A-2, Chemical Formula 2B-1, or Chemical Formula 2B-2. In Chemical Formula 2A-1, X3a, X3b, X3c, X4a, X4b, and X4c independently may be one of N or CRa (wherein Ra may be one of hydrogen, a substituted C1 to C10 alkyl group, or an unsubstituted C1 to C10 alkyl group), R21, R22, R23, and R24 independently may be one of hydrogen, deuterium, a substituted C1 to C30 alkyl group, an unsubstituted C1 to C30 alkyl group, a substituted C1 to C30 alkoxy group, an unsubstituted C1 to C30 alkoxy group, a substituted C6 to C30 aryl group, an unsubstituted C6 to C30 aryl group, a substituted C3 to C30 heteroaryl group, an unsubstituted C3 to C30 heteroaryl group, a halogen, a cyano group (—CN), a cyano-containing group, or a combination thereof, and a and b independently may be an integer of 0 or 1. In Chemical Formula 2A-2, X3a, X3b, X4a, and X4b independently may be one of N or CRa (wherein Ra may be one of hydrogen, a substituted C1 to C10 alkyl group, or an unsubstituted C1 to C10 alkyl group), R21, R22, R23, R24, R25, and R26 independently may be one of hydrogen, deuterium, a substituted C1 to C30 alkyl group, an unsubstituted C1 to C30 alkyl group, a substituted C1 to C30 alkoxy group, an unsubstituted C1 to C30 alkoxy group, a substituted C6 to C30 aryl group, an unsubstituted C6 to C30 aryl group, a substituted C3 to C30 heteroaryl group, an unsubstituted C3 to C30 heteroaryl group, a halogen, a cyano group (—CN), a cyano-containing group, or a combination thereof, and a and b independently may be an integer of 0 or 1. In Chemical Formula 2B-1, X3a, X3b, X4a, and X4b independently may be one of N or CRa (wherein Ra may be one of hydrogen, a substituted C1 to C10 alkyl group, or an unsubstituted C1 to C10 alkyl group), R21, R22, R23, and R24 independently may be one of hydrogen, deuterium, a substituted C1 to C30 alkyl group, an unsubstituted C1 to C30 alkyl group, a substituted C1 to C30 alkoxy group, an unsubstituted C1 to C30 alkoxy group, a substituted C6 to C30 aryl group, an unsubstituted C6 to C30 aryl group, a substituted C3 to C30 heteroaryl group, an unsubstituted C3 to C30 heteroaryl group, a halogen, a cyano group (—CN), a cyano-containing group, or a combination thereof, a and b independently may be an integer of 0 or 1, and G may be one of a single bond, S, Se, Te, O, NRa3, (CRb3Rc3)n, (C(Rd3)═C(Re3)), SiRf3Rg3, or GeRh3Ri3 (wherein Ra3, Rb3, Rc3, Rd3, Re3, Rf3, Rg3, Rh3, and Ri3 independently may be one of hydrogen, a halogen, a substituted C1 to C10 alkyl group, an unsubstituted C1 to C10 alkyl group, a substituted C6 to C10 aryl group, or an unsubstituted C6 to C10 aryl group, and optionally Rd3 and Re3 independently may be present or may be linked with each other to provide a fused ring, and n may be an integer of 1 or 2). In Chemical Formula 2B-2, X3a, X3b, X4a, and X4b independently may be one of N or CRa (wherein Ra may be one of hydrogen, a substituted C1 to C10 alkyl group, or an unsubstituted C1 to C10 alkyl group), R21, R22, R23, and R24 independently may be one of hydrogen, deuterium, a substituted C1 to C30 alkyl group, or an unsubstituted C1 to C30 alkyl group, a substituted C1 to C30 alkoxy group, or an unsubstituted C1 to C30 alkoxy group, a substituted C6 to C30 aryl group, an unsubstituted C6 to C30 aryl group, a substituted C3 to C30 heteroaryl group, an unsubstituted C3 to C30 heteroaryl group, a halogen, a cyano group (—CN), a cyano-containing group, or a combination thereof, a and b independently may be an integer of 0 or 1, and G may be one of a single bond, S, Se, Te, O, NRa3, (CRb3Rc3)n, (C(Rd3)═C(Re3)), SiRf3Rg3, or GeRh3Ri3 (wherein Ra3, Rb3, Rc3, Rd3, Re3, Rf3, Rg3, Rh3, and Ri3 independently may be one of hydrogen, a halogen, a substituted C1 to C10 alkyl group, an unsubstituted C1 to C10 alkyl group, a substituted C6 to C10 aryl group, or an unsubstituted C6 to C10 aryl group, and optionally Rd3 and Re3 independently may be present or may be linked with each other to provide a fused ring, and n may be an integer of 1 or 2). In some example embodiments, the compound may have a maximum absorption wavelength (λmax) in a wavelength region of greater than or equal to about 500 nm and less than about 560 nm, for example about 510 nm to about 550 nm in a thin film state. In some example embodiments, the compound may exhibit a light absorption curve having a full width at half maximum (FWHM) of about 50 nm to about 120 nm, in a thin film state. In some example embodiments, a temperature (e.g., deposition temperature) at which 10 wt % of an initial weight of the compound may be lost may be greater than or equal to about 230° C. According to some example embodiments, an organic photoelectric device includes a first electrode and a second electrode facing each other and an active layer interposed between the first electrode and the second electrode. The active layer may include the compound represented by Chemical Formula 1. In some example embodiments, the active layer may have a maximum absorption wavelength (λmax) in a wavelength region of greater than or equal to about 500 nm and less than about 560 nm, for example about 510 nm to about 550 nm. In some example embodiments, the active layer may exhibit a light absorption curve having a full width at half maximum (FWFIM) of about 50 nm to about 120 nm, in a thin film state. According to some example embodiments, an image sensor may include the organic photoelectric device. In some example embodiments, the image sensor may include a semiconductor substrate integrated with a plurality of first photo-sensing devices configured to sense light in a blue wavelength region and a plurality of second photo-sensing devices configured to sense light in a red wavelength region, and the organic photoelectric device on the semiconductor substrate and configured to selectively sense light in a green wavelength region. In some example embodiments, the first photo-sensing device and the second photo-sensing device may be stacked in a vertical direction in the semiconductor substrate. In some example embodiments, the image sensor may further include a color filter layer between the semiconductor substrate and the organic photoelectric device. The color filter layer may include a blue filter configured to selectively transmit light in a blue wavelength region and a red filter configured to selectively transmit light in a red wavelength region. In some example embodiments, the image sensor may further include a blue photoelectric device and red photoelectric device. The organic photoelectric device may include a green photoelectric device. The green photoelectric device, the blue photoelectric device, and the red photoelectric device may be stacked. The blue photoelectric device may be configured to selectively sense light in a blue wavelength region. The red photoelectric device may be configured to selectively sense light in a red wavelength region. The green photoelectric device may be configured to selectively sense light in a green wavelength region. According to some example embodiments, an electronic device includes the image sensor. According to example embodiments, a compound represented by Chemical Formula 1 may be provided. In Chemical Formula 1, X1 may be one of S, Se, Te, O, S(═O), S(═O)2, NRa1, SiRb1Rc1, or GeRd1Re1 (wherein Ra1, Rb1, Rc1, Rd1, and Re1 independently may be one of hydrogen, a substituted C1 to C10 alkyl group, or an unsubstituted C1 to C10 alkyl group), R1 to R3 independently may be one of hydrogen, deuterium, a substituted C1 to C30 alkyl group, an unsubstituted C1 to C30 alkyl group, a substituted C1 to C30 alkoxy group, an unsubstituted C1 to C30 alkoxy group, a substituted C6 to C30 aryl group, an unsubstituted C6 to C30 aryl group, a substituted C3 to C30 heteroaryl group, an unsubstituted C3 to C30 heteroaryl group, a substituted C2 to C30 acyl group, an unsubstituted C2 to C30 acyl group, a halogen, a cyano group (—CN), a cyano-containing group, a nitro group, —SiRaRbRc (wherein Ra, Rb, and Rc independently may be one of hydrogen, a substituted C1 to C10 alkyl group, or an unsubstituted C1 to C10 alkyl group), or a combination thereof, and Y may be a functional group represented by Chemical Formula 2A or Chemical Formula 2B. In Chemical Formula 2A, Ar1 and Ar2 independently may be one of a substituted C6 to C30 aryl group, an unsubstituted C6 to C30 aryl group, a substituted C3 to C30 heteroaryl group, or an unsubstituted C3 to C30 heteroaryl group. In Chemical Formula 2B, Ar3 and Ar4 independently may be one of a substituted C6 to C30 arylene group, an unsubstituted C6 to C30 arylene group, a substituted C3 to C30 heteroarylene group, or an unsubstituted C3 to C30 heteroarylene group. G may be one of a single bond, S, Se, Te, O, NRa3, (CRb3Rc3)n, (C(Rd3)═C(Re3)), SiRf3Rg3, or GeRh3Ri3 (wherein Ra3, Rb3, Rc3, Rd3, Re3, Rf3, Rg3, Rh3, and Ri3 independently may be one of hydrogen, a halogen, a substituted C1 to C10 alkyl group, an unsubstituted C1 to C10 alkyl group, a substituted C6 to C10 aryl group, or an unsubstituted C6 to C10 aryl group, and optionally Rd3 and Re3 independently may be present or may be linked with each other to provide a fused ring, and n may be an integer of 1 or 2). In Chemical Formula 1, Ar may include one of the structures represented by Chemical Formulae 3A to 3E. In Chemical Formula 3A, X2a may be one of S, Se, Te, O, S(═O), S(═O)2, NRa2, CRc2Rd2, SiRe2Rf2, or GeRg2Rh2 (wherein, Ra2, Rc2, Rd2, Re2, Rf2, Rg2, and Rh2 independently may be one of hydrogen, a substituted C1 to C10 alkyl group, or an unsubstituted C1 to C10 alkyl group). In Chemical Formula 3B, X2b may be one of N or CRb2 (wherein, Rb2 may be one of hydrogen, a substituted C1 to C10 alkyl group, or an unsubstituted C1 to C10 alkyl group). In Chemical Formulae 3C and 3D, X2b may be N. In Chemical Formulae 3A to 3E, R11 to R17 independently may be one of hydrogen, deuterium, a substituted C1 to C30 alkyl group, an unsubstituted C1 to C30 alkyl group, a substituted C1 to C30 alkoxy group, an unsubstituted C1 to C30 alkoxy group, a substituted C6 to C30 aryl group, an unsubstituted C6 to C30 aryl group, a substituted C3 to C30 heteroaryl group, an unsubstituted C3 to C30 heteroaryl group, a substituted C2 to C30 acyl group, an unsubstituted C2 to C30 acyl group, a halogen, a cyano group (—CN), a cyano-containing group, a nitro group, —SiRaRbRc (wherein Ra, Rb, and Rc independently may be one of hydrogen, a substituted C1 to C10 alkyl group, or an unsubstituted C1 to C10 alkyl group), or a combination thereof. In Chemical Formulae 3A to 3D, R11 to R17 independently may be present or an adjacent two thereof may be linked with each other to provide a fused ring. In some example embodiments, in Chemical Formula 2A, at least one of Ar1 and Ar2 may include a heteroatom selected from nitrogen (N), sulfur (S), and selenium (Se). Alternatively, in Chemical Formula 2B, at least one of Ar3 and Ar4 may include a heteroatom selected from nitrogen (N), sulfur (S), and selenium (Se). In some example embodiments, in Chemical Formula 1, Y may be represented by Chemical Formula 2A-1, Chemical Formula 2A-2, Chemical Formula 2B-1, or Chemical Formula 2B-2: In Chemical Formula 2A-1, Chemical Formula 2A-2, Chemical Formula 2B-1, or Chemical Formula 2B-2, X3a, X3b, X3c, X4a, X4b, and X4c independently may be one of N or CRa (wherein Ra may be one of hydrogen, a substituted C1 to C10 alkyl group, or an unsubstituted C1 to C10 alkyl group), R21 to R25 independently may be one of hydrogen, deuterium, a substituted C1 to C30 alkyl group, an unsubstituted C1 to C30 alkyl group, a substituted C1 to C30 alkoxy group, an unsubstituted C1 to C30 alkoxy group, a substituted C6 to C30 aryl group, an unsubstituted C6 to C30 aryl group, a substituted C3 to C30 heteroaryl group, an unsubstituted C3 to C30 heteroaryl group, a halogen, a cyano group (—CN), a cyano-containing group, or a combination thereof, and a and b independently may be an integer of 0 or 1. In Chemical Formula 2B-1 and Chemical Formula 2B-2, G may be one of a single bond, S, Se, Te, O, NRa3, (CRb3Rc3)n, (C(Rd3)═C(Re3)), SiRf3Rg3, or GeRh3Ri3 (wherein Ra3, Rb3, Rc3, Rd3, Re3, Rf3, Rg3, Rh3, and Ri3 independently may be one of hydrogen, a halogen, a substituted C1 to C10 alkyl group, an unsubstituted C1 to C10 alkyl group, a substituted C6 to C10 aryl group, or an unsubstituted C6 to C10 aryl group, and optionally Rd3 and Re3 independently may be present or may be linked with each other to provide a fused ring, and n may be an integer of 1 or 2). In some example embodiments, an organic photoelectric device, may include the above-referenced compound in an active layer, a first electrode; and a second electrode facing the first electrode. The active layer may be between the first electrode and the second electrode. In some example embodiments, an image sensor may include the organic photoelectric device and a substrate. The organic photoelectric device may be on the substrate. The compound selectively absorbs light in a green wavelength region and has excellent deposition stability, heat resistance, and oxidation resistance, and the organic photoelectric device, the image sensor, and the electronic device exhibit improved efficiency by increasing wavelength selectivity in a green wavelength region due to the compound. Example embodiments will hereinafter be described in detail, and may be easily performed by a person having an ordinary skill in the related art. However, this disclosure may be embodied in many different forms and is not to be construed as limited to the exemplary embodiments set forth herein. In the drawings, the thickness of layers, regions, etc., are exaggerated for clarity. Like reference numerals designate like elements throughout the specification. It will be understood that when an element such as a layer, film, region, or plate is referred to as being “on” another element, it can be directly on the other element or intervening elements may also be present. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present. In the drawings, parts having no relationship with the description are omitted for clarity of the embodiments, and the same or similar constituent elements are indicated by the same reference numeral throughout the specification. As used herein, when specific definition is not otherwise provided, the term “substituted” refers to replacement of a hydrogen valence halogen atom (F, Br, Cl, or I), a hydroxy group, a nitro group, a cyano group, an amino group, an azido group, an amidino group, a hydrazino group, a hydrazono group, a carbonyl group, a carbamyl group, a thiol group, an ester group, a carboxyl group or a salt thereof, a sulfonic acid group or a salt thereof, phosphoric acid group or a salt thereof, a C1 to C20 alkyl group, a C1 to C20 alkoxy group, a C2 to C20 alkenyl group, a C2 to C20 alkynyl group, a C6 to C30 aryl group, a C7 to C30 arylalkyl group, a C2 to C20 heteroaryl group, a C3 to C20 heteroarylalkyl group, a C3 to C30 cycloalkyl group, a C3 to C15 cycloalkenyl group, a C6 to C15 cycloalkynyl group, a C2 to C20 heterocycloalkyl group, and a combination thereof. As used herein, when specific definition is not otherwise provided, the term “hetero” refers to one including 1 to 3 heteroatoms selected from N, O, S, P, and Si. As used herein, the term “alkyl group” for example refers to a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, an isobutyl group, a t-butyl group, a pentyl group, a hexyl group, and the like. As used herein, the term “cycloalkyl group” for example refers to a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, and the like. As used herein, the term “aryl group” refers to a substituent including all element of the cycle having p-orbitals which form conjugation, and may be a monocyclic, polycyclic or fused ring polycyclic (i.e., rings sharing adjacent pairs of carbon atoms) functional group. As used herein, when a definition is not otherwise provided, the term “cyano-containing group” refers to a monovalent group such as a C1 to C30 alkyl group, a C2 to C30 alkenyl group, or a C2 to C30 alkynyl group where at least one hydrogen is substituted with a cyano group. The cyano-containing group also refers to a divalent group such as a dicyanoalkenyl group represented by ═CRx′—(CRxRy)p—CRy′(CN)2 wherein Rx, Ry, Rx′, and Ry′ are independently hydrogen or a C1 to C10 alkyl group and p is an integer of 0 to 10. Specific examples of the cyano-containing group may be a dicyanomethyl group, a dicyanovinyl group, a cyanoethynyl group, and the like. As used herein, when a definition is not otherwise provided, the term “combination thereof” refers to at least two substituents bound to each other by a single bond or a C1 to C10 alkylene group, or at least two fused substituents. Expressions such as “at least one of,” when preceding a list of elements (e.g., A, B, and C), modify the entire list of elements and do not modify the individual elements of the list. For example, “at least one of A, B, and C,” “at least one of A, B, or C,” “one of A, B, C, or a combination thereof,” and “one of A, B, C, and a combination thereof,” respectively, may be construed as covering any one of the following combinations: A; B; A and B; A and C; B and C; and A, B, and C.” Hereinafter, a compound according to an embodiment is described. The compound is represented by Chemical Formula 1. In Chemical Formula 1, X1 is one of S, Se, Te, O, S(═O), S(═O)2, NRa1, SiRb1Rc1, and GeRd1Re1 (wherein Ra1, Rb1, Rc1, Rd1, and Re1 are independently one of hydrogen and a substituted or unsubstituted C1 to C10 alkyl group), Ar is an aromatic ring group including N and X2 (wherein X2 is one of S, Se, Te, O, S(═O), S(═O)2, N, NRa2, CRb2, CRc2Rd2, SiRe2Rf2, and GeRg2Rh2, and Ra2, Rb2, Rc2, Rd2, Re2, Rf2, Rg2, and Rh2 are independently one of hydrogen and a substituted or unsubstituted C1 to C10 alkyl group), R1 to R3 are independently one of hydrogen, deuterium, a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C1 to C30 alkoxy group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C3 to C30 heteroaryl group, a substituted or unsubstituted C2 to C30 acyl group, a halogen, a cyano group (—CN), a cyano-containing group, a nitro group, —SiRaRbRc (wherein Ra, Rb, and Rc are independently one of hydrogen and a substituted or unsubstituted C1 to C10 alkyl group), and a combination thereof, and Y is a functional group represented by Chemical Formula 2A or Chemical Formula 2B. In Chemical Formula 2A, Ar1 and Ar2 are independently one of a substituted or unsubstituted C6 to C30 aryl group and a substituted or unsubstituted C3 to C30 heteroaryl group. In Chemical Formula 2B, Ar3 and Ar4 are independently one of a substituted or unsubstituted C6 to C30 arylene group and a substituted or unsubstituted C3 to C30 heteroarylene group, and G is one of a single bond, S, Se, Te, O, NRa3, (CRb3Rc3)n, (C(Rd3)═C(Re3)), SiRf3Rg3, and GeRh3Ri3 (wherein Ra3, Rb3, Rc3, Rd3, Re3, Rf3, Rg3, Rh3, and Ri3 are independently one of hydrogen, a halogen, a substituted or unsubstituted C1 to C10 alkyl group, and a substituted or unsubstituted C6 to C10 aryl group, and optionally Rd3 and Re3 are independently present or are linked with each other to provide a fused ring, and n is an integer of 1 or 2). The compound represented by Chemical Formula 1 includes an electron donor moiety represented by Y; a linker including an X1-containing 5-membered ring; and unsaturated nitrile and an electron acceptor moiety of an aromatic ring group (Ar) including N and X2. In Chemical Formula 1, examples of the substituted or unsubstituted C1 to C30 alkyl group may be a haloalkyl group, examples of the substituted or unsubstituted C2 to C30 acyl group may be an acetyl group, and examples of the halogen may be F, Cl, Br, or I. In Chemical Formula 1, Ar may be represented by one of Chemical Formula 3A to Chemical Formula 3E. In Chemical Formula 3A, X2a is one of S, Se, Te, O, S(═O), S(═O)2, NRa2, CRc2Rd2, SiRe2Rf2, and GeRg2Rh2 (wherein, Ra2, Rc2, Rd2, Re2, Rf2, Rg2, and Rh2 are independently one of hydrogen and a substituted or unsubstituted C1 to C10 alkyl group), and R11 to R16 are independently one of hydrogen, deuterium, a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C1 to C30 alkoxy group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C3 to C30 heteroaryl group, a substituted or unsubstituted C2 to C30 acyl group, a halogen, a cyano group (—CN), a cyano-containing group, a nitro group, —SiRaRbRc (wherein Ra, Rb, and Rc are independently one of hydrogen and a substituted or unsubstituted C1 to C10 alkyl group), and a combination thereof, wherein R11 to R16, Ra2, Rc2, Rd2, Re2, Rf2, Rg2, and Rh2 are independently present or an adjacent two thereof are linked with each other to provide a fused ring. The substituted C1 to C30 alkyl group may be a C1 to C30 fluoroalkyl group, for example a C1 to C30 perfluoroalkyl group. In Chemical Formula 3B, X2b is one of N and CRb2 (wherein, Rb2 is one of hydrogen and a substituted or unsubstituted C1 to C10 alkyl group), and R11 to R17 are independently one of hydrogen, deuterium, a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C1 to C30 alkoxy group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C3 to C30 heteroaryl group, a substituted or unsubstituted C2 to C30 acyl group, a halogen, a cyano group (—CN), a cyano-containing group, a nitro group, —SiRaRbRc (wherein Ra, Rb, and Rc are independently one of hydrogen and a substituted or unsubstituted C1 to C10 alkyl group), and a combination thereof, wherein R11 to R17 and Rb2 are independently present or an adjacent two thereof are linked with each other to provide a fused ring. The substituted C1 to C30 alkyl group may be a C1 to C30 fluoroalkyl group, for example a C1 to C30 perfluoroalkyl group. In Chemical Formula 3C, X2b is one of N and CRb2 (wherein, Rb2 is one of hydrogen and a substituted or unsubstituted C1 to C10 alkyl group), and R11 to R17 are independently one of hydrogen, deuterium, a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C1 to C30 alkoxy group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C3 to C30 heteroaryl group, a substituted or unsubstituted C2 to C30 acyl group, a halogen, a cyano group (—CN), a cyano-containing group, a nitro group, —SiRaRbRc (wherein Ra, Rb, and Rc are independently one of hydrogen and a substituted or unsubstituted C1 to C10 alkyl group), and a combination thereof, wherein R11 to R17 and Rb2 are independently present or an adjacent two thereof are linked with each other to provide a fused ring. The substituted C1 to C30 alkyl group may be a C1 to C30 fluoroalkyl group, for example a C1 to C30 perfluoroalkyl group. In Chemical Formula 3D, X2b is one of N and CRb2 (wherein, Rb2 is one of hydrogen and a substituted or unsubstituted C1 to C10 alkyl group), and R11 to R17 are independently one of hydrogen, deuterium, a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C1 to C30 alkoxy group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C3 to C30 heteroaryl group, a substituted or unsubstituted C2 to C30 acyl group, a halogen, a cyano group (—CN), a cyano-containing group, a nitro group, —SiRaRbRc (wherein Ra, Rb, and Rc are independently one of hydrogen and a substituted or unsubstituted C1 to C10 alkyl group), and a combination thereof, wherein R11 to R17 and Rb2 are independently present or an adjacent two thereof are linked with each other to provide a fused ring. The substituted C1 to C30 alkyl group may be a C1 to C30 fluoroalkyl group, for example a C1 to C30 perfluoroalkyl group. In Chemical Formula 3E, R11 and R12 are independently one of hydrogen, deuterium, a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C1 to C30 alkoxy group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C3 to C30 heteroaryl group, a substituted or unsubstituted C2 to C30 acyl group, a halogen, a cyano group (—CN), a cyano-containing group, a nitro group, —SiRaRbRc (wherein Ra, Rb, and Rc are independently one of hydrogen and a substituted or unsubstituted C1 to C10 alkyl group), and a combination thereof. The substituted C1 to C30 alkyl group may be a C1 to C30 fluoroalkyl group, for example a C1 to C30 perfluoroalkyl group. In Chemical Formulae 3A to 3E, a fused ring is formed by combining a ring formed by linking adjacent two groups among R11 to R16, Ra2, Rc2, Rd2, Re2, Rf2, Rg2 and Rh2 of Chemical Formula 3A or a ring formed by linking adjacent two groups among R11 to R17 and Rb2 of Chemical Formulae 3B to 3D, with an aromatic ring of Chemical Formulae 3A to 3E and may include two or more 5-membered or 6-membered ring groups or a non-aromatic 5-membered or 6-membered ring group. The ring formed by linking adjacent two groups among R11 to R16, Ra2, Rc2, Rd2, Re2, Rf2, Rg2, and Rh2 in Chemical Formula 3A may be at least two, and in addition, the ring formed by linking adjacent two groups among R11 to R17 and Rb2 in Chemical Formulae 3B to 3D may be at least two. In addition, the fused ring may include a heteroatom, and the heteroatom may be selected from nitrogen (N), sulfur (S), selenium (Se), tellurium (Te), oxygen (O), germanium (Ge), and silicon (Si). In Chemical Formula 2A, at least one of Ar1 and Ar2 may include a heteroatom selected from nitrogen (N), sulfur (S), and selenium (Se). Ar1 and Ar2 may be a substituted or unsubstituted C6 to C30 aryl group or a substituted or unsubstituted C3 to C30 heteroaryl group, for example a substituted or unsubstituted C6 to C20 aryl group or a substituted or unsubstituted C3 to C20 heteroaryl group. In example embodiments, the aryl group may be selected from a phenyl group, a naphthyl group, and an anthracenyl group and the heteroaryl group may be selected from a pyrrolyl group, a prazolyl group, an imidazolyl group, an oxazolyl group, an isoxazolyl group, a thiazolyl group, an isothiazolyl group, a pyridinyl group, a pyridazinyl group, a pyrimidinyl group, a pyrazinyl group, an indolyl group, a quinolinyl group, an isoquinolinyl group, an naphthyridinyl group, a cinnolinyl group, a quinazolinyl group, a phthalazinyl group, a benzotriazinyl group, a pyridopyrazinyl group, a pyridopyrimidinyl group, a pyridopyridazinyl group, a thienyl group, a benzothienyl group, a selenophenyl group, and a benzoselenophenyl group. In Chemical Formula 2B, at least one of Ar3 and Ar4 may include a heteroatom selected from nitrogen (N), sulfur (S), and selenium (Se). Ar3 and Ar4 may be a substituted or unsubstituted C6 to C30 arylene group or a substituted or unsubstituted C3 to C30 heteroarylene group, for example a substituted or unsubstituted C6 to C20 arylene group or a substituted or unsubstituted C3 to C20 heteroarylene group. In example embodiments, the arylene group may be selected from a phenylene group, a naphthalene group, and an anthracene group and the arylene group may be selected from a pyrrolylene group, a prazolylene group, an imidazolylene group, an oxazolylene group, an isoxazolylene group, a thiazolylene group, an isothiazolylene group, a pyridinylene group, a pyridazinylene group, a pyrimidinylene group, a pyrazinylene group, an indolylene group, a quinolinylene group, an isoquinolinylene group, a naphthyridinylene group, a cinnolinylene group, a quinazolinylene group, a phthalazinylene group, a benzotriazinylene group, a pyridopyrazinylene group, a pyridopyrimidinylene group, a pyridopyridazinylene group, a thienylene group, a benzothienylene group, a selenophenylene group, and a benzoselenophenylene group. In Chemical Formula 1, Y may be a functional group represented by Chemical Formula 2A-1, Chemical Formula 2A-2, Chemical Formula 2B-1, or Chemical Formula 2B-2. In Chemical Formula 2A-1, X3a, X3b, X3c, X4a, X4b, and X4c are independently one of N and CRa (wherein Ra is one of hydrogen and a substituted or unsubstituted C1 to C10 alkyl group), R21, R22, R23, and R24 are independently one of hydrogen, deuterium, a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C1 to C30 alkoxy group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C3 to C30 heteroaryl group, a halogen, a cyano group (—CN), a cyano-containing group, and a combination thereof, and a and b are independently an integer of 0 or 1. In Chemical Formula 2A-2, X3a, X3b, X4a, and X4b are independently one of N and CRa (wherein Ra is one of hydrogen and a substituted or unsubstituted C1 to C10 alkyl group), R21, R22, R23, R24, R25, and R26 are independently one of hydrogen, deuterium, a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C1 to C30 alkoxy group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C3 to C30 heteroaryl group, a halogen, a cyano group (—CN), a cyano-containing group, and a combination thereof, and a and b are independently an integer of 0 or 1. In Chemical Formula 2B-1, X3a, X3b, X4a, and X4b are independently one of N and CRa (wherein Ra is one of hydrogen and a substituted or unsubstituted C1 to C10 alkyl group), R21, R22, R23, and R24 are independently one of hydrogen, deuterium, a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C1 to C30 alkoxy group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C3 to C30 heteroaryl group, a halogen, a cyano group (—CN), a cyano-containing group, and a combination thereof, a and b are independently an integer of 0 or 1, and G is one of a single bond, S, Se, Te, O, NRa3, (CRb3Rc3)n, (C(Rd3)═C(Re3)), SiRf3Rg3, and GeRh3Ri3 (wherein Ra3, Rb3, Rc3, Rd3, Re3, Rf3, Rg3, Rh3, and Ri3 are independently one of hydrogen, a halogen, a substituted or unsubstituted C1 to C10 alkyl group, and a substituted or unsubstituted C6 to C10 aryl group, and optionally Rd3 and Re3 are independently present or are linked with each other to provide a fused ring, and n is an integer of 1 or 2). In Chemical Formula 2B-2, X3a, X3b, X4a, and X4b are independently one of N and CRa (wherein Ra is one of hydrogen and a substituted or unsubstituted C1 to C10 alkyl group), R21, R22, R23, and R24 are independently one of hydrogen, deuterium, a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C1 to C30 alkoxy group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C3 to C30 heteroaryl group, a halogen, a cyano group (—CN), a cyano-containing group, and a combination thereof, a and b are independently an integer of 0 or 1, and G is one of a single bond, S, Se, Te, O, NRa3, (CRb3Rc3)n, (C(Rd3)═C(Re3)), SiRf3Rg3, and GeRh3Ri3 (wherein Ra3, Rb3, Rc3, Rd3, Re3, Rf3, Rg3, Rh3, and Ri3 are independently one of hydrogen, a halogen, a substituted or unsubstituted C1 to C10 alkyl group, and a substituted or unsubstituted C6 to C10 aryl group, and optionally Rd3 and Re3 are independently present or are linked with each other to provide a fused ring, and n is an integer of 1 or 2). Examples of the compound represented by Chemical Formula 1 may be compounds represented by Chemical Formula 4-1, but are not limited thereto. In Chemical Formula 4-1, X1, X2, R1 to R3, R11 to R16, and R21 to R24 are the same as described above. Examples of the compound represented by Chemical Formula 1 may be compounds represented by Chemical Formula 4-1A or Chemical Formula 4-2A, but is not limited thereto. In Chemical Formula 4-1A, hydrogen of each aromatic ring may be replaced by a substituent selected from a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C1 to C30 alkoxy group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C3 to C30 heteroaryl group, a halogen (F, Cl, Br or I), a cyano group (—CN), a cyano-containing group, and a combination thereof. In Chemical Formula 4-2A, hydrogen of each aromatic ring may be replaced by a substituent selected from a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C1 to C30 alkoxy group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C3 to C30 heteroaryl group, a halogen (F, Cl, Br or I), a cyano group (—CN), a cyano-containing group, and a combination thereof. The compound may be a compound selectively absorbing light in a green wavelength region, and may have a maximum absorption wavelength (λmax) in a wavelength region of greater than or equal to about 500 nm, for example greater than or equal to about 505 nm, greater than or equal to about 510 nm, greater than or equal to about 515 nm, or greater than or equal to about 520 nm. In addition, the compound may have a maximum absorption wavelength (Amax) in a wavelength region of less than or equal to about 560 nm, for example less than or equal to about 555 nm, less than or equal to about 550 nm, less than or equal to about 545 nm, or less than or equal to about 540 nm. The compound may exhibit a light absorption curve having a full width at half maximum (FWHM) of greater than or equal to about 50 nm and less than or equal to about 120 nm, for example less than or equal to about 110 nm in a thin film state. Herein, the FWFIM is a width of a wavelength corresponding to half of a maximum absorption point. As used herein, when specific definition is not otherwise provided, it may be defined by absorbance measured by UV-Vis spectroscopy. When the full width at half maximum (FWFIM) is within the range, selectivity in a green wavelength region may be increased. The thin film may be a thin film deposited under a vacuum condition. The compound may be formed into a thin film by using a deposition method. The deposition method may provide a uniform thin film and have small inclusion possibility of impurities into the thin film, but when the compound has a lower melting point than a temperature for the deposition, a product decomposed from the compound may be deposited and thus performance of a device may be deteriorated. Accordingly, the compound desirably has a higher melting point than the deposition temperature. The compound may have greater than or equal to about 3° C., for example greater than or equal to about 10° C. a higher melting point than the deposition temperature and thus may be desirably used for the deposition. Specifically, a donor/acceptor-type material represented by Chemical Formula 1 may be thermally decomposed at its melting point (Tm). Accordingly, when the material has a lower Tm than a sublimation temperature (Ts) at which the material is vacuum-deposited to form a film, the material may be decomposed before being sublimated (deposited) and not be used to manufacture a device. Since this material is not be appropriate for manufacturing a stable image sensor, Tm should be higher than Ts, and desirably, Tm-Ts≥3° C. In addition, a temperature (deposition temperature) at which 10 wt % of an initial weight of the compound is lost may be greater than or equal to about 230° C., for example greater than or equal to about 240° C. The compound has improved deposition stability and heat resistance by including a —CN group (unsaturated nitrile) and a —C═N— group of an aromatic ring group (Ar), and thus purity of a thin film therefrom after continuous deposition is improved and performance of a device is not decreased in accordance with a deposition number. In addition, a micro lens array (MLA) needs to be formed to concentrate light after manufacturing an organic photoelectric device during manufacture of an image sensor. This micro lens array requires a relatively high temperature (about 160° C.), and this heat treatment may deteriorate performance of the organic photoelectric device. The performance deterioration of the organic photoelectric device during the heat treatment of MLA may be caused not by chemical decomposition of an organic material but its morphology change. The morphology change is in general caused, when a material starts a thermal agitation due to a heat treatment, but even a material having a firm molecule structure may not have the thermal agitation and be prevented from the deterioration by the heat treatment. The compound may have improved heat-resistance due to the —CN group (unsaturated nitrile) and the —C═N— group of an aromatic ring group (Ar) in a donor region, and may be stably maintained during the MLA heat treatment securing process stability. Since the compound works as a p-type semiconductor, the compound may be appropriately used, as long as it has a higher LUMO level than an n-type semiconductor. For example, when the compound is mixed with an n-type material such as fullerene, the compound desirably has a higher LUMO level than 4.2 eV than the fullerene having a LUMO level of 4.2 eV. As for the appropriate HOMO-LUMO level of the compound, when the compound has a HOMO level ranging from about 5.0 eV to about 5.8 eV and an energy bandgap ranging from about 1.9 eV to about 2.3 eV, the LUMO level of the compound is in a range of about 3.9 eV to about 2.7 eV. The compound having a HOMO level, an LUMO level, and an energy bandgap within the ranges may be used as a p-type semiconductor compound effectively absorbing light in a green wavelength region, and thus has high external quantum efficiency (EQE) and resultantly improves photoelectric conversion efficiency. In example embodiments, in view of a thin film formation, a compound that may be deposited in a stable process is desirable and thus the compound has a molecular weight of about 300 to about 1500. However, even though the compound has a molecular weight out of the range, a depositable compound may be used without limitation. In addition, when the compound is formed to form a thin film using a coating process, a compound that is dissolved in a solvent and coated may be used without limitation. The compound may be a p-type semiconductor compound. Hereinafter, an organic photoelectric device including the compound according to an example embodiment is described with reference to drawings. FIG. 1 is a cross-sectional view showing an organic photoelectric device according to an example embodiment. Referring to FIG. 1, an organic photoelectric device 100 according to an example embodiment includes a first electrode 10 and a second electrode 20, and an active layer 30 between the first electrode 10 and the second electrode 20. One of the first electrode 10 and the second electrode 20 is an anode and the other is a cathode. At least one of the first electrode 10 and the second electrode 20 may be a light-transmitting electrode, and the light-transmitting electrode may be made of, for example, a transparent conductor such as indium tin oxide (ITO) or indium zinc oxide (IZO), or a metal thin layer of a thin single layer or multilayer. When one of the first electrode 10 and the second electrode 20 is a non-light-transmitting electrode, it may be made of, for example, an opaque conductor such as aluminum (Al). The active layer 30 includes a p-type semiconductor and an n-type semiconductor to form a pn junction, and absorbs external light to generate excitons and then separates the generated excitons into holes and electrons. The active layer 30 includes the compound represented by Chemical Formula 1. The compound may act as a p-type semiconductor compound in the active layer 30. The compound is a compound selectively absorbing light in a green wavelength region, and the active layer 30 including the compound may have a maximum absorption wavelength (λmax) in a wavelength region of greater than or equal to about 500 nm, for example greater than or equal to about 505 nm, greater than or equal to about 510 nm, greater than or equal to about 515 nm, or greater than or equal to about 520 nm and less than or equal to about 560 nm, for example less than or equal to about 555 nm, less than or equal to about 550 nm, less than or equal to about 545 nm, or less than or equal to about 540 nm. The active layer 30 may exhibit a light absorption curve having a relatively narrow full width at half maximum (FWHM) of about 50 nm to about 120 nm, for example about 50 nm to about 110 nm. Accordingly, the active layer 30 has high selectivity for light in a green wavelength region. The active layer may have an absorption coefficient of greater than or equal to about 5.5×104 cm−1, for example about 5.8×104 cm−1 to about 10×104 cm−1 or about 7.0×104 cm−1 to about 10×104 cm−1 when including the compound Chemical Formula 1 and C60 in a volume ratio of about 0.9:1 to about 1.1:1, for example about 1:1. The active layer 30 may further include an n-type semiconductor compound for forming a pn junction. The n-type semiconductor compound may be sub-phthalocyanine or a sub-phthalocyanine derivative, fullerene or a fullerene derivative, thiophene or a thiophene derivative, or a combination thereof. The fullerene may include C60, C70, C76, C78, C80, C82, C84, C90, C96, C240, C540, a mixture thereof, a fullerene nanotube, and the like. The fullerene derivative may refer to compounds of these fullerenes having a substituent attached thereto. The fullerene derivative may include a substituent such as alkyl group, aryl group, or a heterocyclic group. Examples of the aryl groups and heterocyclic groups may be are a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, a fluorene ring, a triphenylene ring, a naphthacene ring, a biphenyl ring, a pyrrole ring, a furan ring, a thiophene ring, an imidazole ring, an oxazole ring, a thiazole ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a pyridazine ring, an indolizine ring, an indole ring, a benzofuran ring, a benzothiophene ring, an isobenzofuran ring, a benzimidazole ring, an imidazopyridine ring, a quinolizidine ring, a quinoline ring, a phthalazine ring, a naphthyridine ring, a quinoxaline ring, a quinoxazoline ring, an isoquinoline ring, a carbazole ring, a phenanthridine ring, an acridine ring, a phenanthroline ring, a thianthrene ring, a chromene ring, an xanthene ring, a phenoxathin ring, a phenothiazine ring, or a phenazine ring. The sub-phthalocyanine or the sub-phthalocyanine derivative may be represented by Chemical Formula 5. In Chemical Formula 5, R31 to R33 are independently one of hydrogen, a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C1 to C30 alkoxy group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C3 to C30 heteroaryl group, a substituted or unsubstituted C2 to C30 acyl group, a halogen, a halogen-containing group, and a combination thereof, a, b, and c are integers ranging from 1 to 3, and Z is a monovalent substituent. For example, Z may be a halogen or a halogen-containing group, for example F, Cl, an F-containing group, or a Cl-containing group. The halogen refers to F, Cl, Br, or I and the halogen-containing group refers to alkyl group where at least one of hydrogen is replaced by F, Cl, Br, or I. The thiophene derivative may be for example represented by 6 or Chemical Formula 7, but is not limited thereto. In Chemical Formulae 6 and 7, T1, T2, and T3 are aromatic rings including substituted or unsubstituted thiophene moieties, T1, T2, and T3 are independently present or are fused to each other, X3 to X8 are independently hydrogen, a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C1 to C30 alkoxy group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C3 to C30 heterocyclic group, a cyano group, or a combination thereof, and EWG1 and EWG2 are independently electron withdrawing groups. For example, in Chemical Formula 6, at least one of X3 to X8 may be an electron withdrawing group, for example a cyano-containing group. The active layer 30 may further include a second p-type semiconductor compound selectively absorbing green light. The p-type semiconductor compound may be a compound represented by Chemical Formula 8. In Chemical Formula 8, R41 to R43 are independently selected from hydrogen, a substituted or unsubstituted C1 to C30 aliphatic hydrocarbon group, a substituted or unsubstituted C6 to C30 aromatic hydrocarbon group, a substituted or unsubstituted C1 to C30 aliphatic heterocyclic group, a substituted or unsubstituted C2 to C30 aromatic heterocyclic group, a substituted or unsubstituted C1 to C30 alkoxy group, a substituted or unsubstituted C6 to C30 aryloxy group, thiol group, a substituted or unsubstituted C6 to C30 alkylthio group, a substituted or unsubstituted C6 to C30 arylthio group, a cyano group, a cyano-containing group, a halogen, a halogen-containing group, a substituted or unsubstituted sulfonyl group (e.g., a substituted or unsubstituted C0 to C30 aminosulfonyl group, a substituted or unsubstituted C1 to C30 alkylsulfonyl group or a substituted or unsubstituted C6 to C30 arylsulfonyl group), or a combination thereof, or two adjacent groups of R41 to R43 are linked with each other to provide a fused ring, L1 to L3 are independently a single bond, a substituted or unsubstituted C1 to C30 alkylene group, a substituted or unsubstituted C6 to C30 arylene group, divalent substituted or unsubstituted C3 to C30 heterocyclic group, or a combination thereof, R51 to R53 are independently a substituted or unsubstituted C1 to C30 alkyl group, a substituted or unsubstituted C1 to C30 alkoxy group, a substituted or unsubstituted C6 to C30 aryl group, a substituted or unsubstituted C3 to C30 heterocyclic group, a substituted or unsubstituted C1 to C30 alkoxy group, a substituted or unsubstituted amine group (e.g., a substituted or unsubstituted C1 to C30 alkylamine group or a substituted or unsubstituted C6 to C30 arylamine group), a substituted or unsubstituted silyl group, or a combination thereof, and a to c are independently an integer ranging from 0 to 4. The second p-type semiconductor compound selectively absorbing green light may be included in an amount of about 500 to about 1500 parts by weight based on 100 parts by weight of the compound represented by Chemical Formula 1. The active layer 30 may be a single layer or a multilayer. The active layer 30 may be, for example, an intrinsic layer (I layer), a p-type layer/l layer, an I layer/n-type layer, a p-type layer/l layer/n-type layer, a p-type layer/n-type layer, and the like. The intrinsic layer (I layer) may include the compound of Chemical Formula 1 and the n-type semiconductor compound in a ratio of about 1:100 to about 100:1. The compound of Chemical Formula 1 and the n-type semiconductor compound may be included in a ratio ranging from about 1:50 to about 50:1 within the range, specifically, about 1:10 to about 10:1, and more specifically, about 1:1. When the compound of Chemical Formula 1 and the n-type semiconductor compound have a composition ratio within the range, an exciton may be effectively produced, and a pn junction may be effectively formed. The p-type layer may include the compound of Chemical Formula 1, and the n-type layer may include the n-type semiconductor compound. The active layer 30 may have a thickness of about 1 nm to about 500 nm and specifically, about 5 nm to about 300 nm. When the active layer 30 has a thickness within the range, the active layer may effectively absorb light, effectively separate holes from electrons, and deliver them, thereby effectively improving photoelectric conversion efficiency. An optimal thickness of a thin film may be, for example, determined by an absorption coefficient of the active layer 30, and may be, for example, a thickness being capable of absorbing light of at least about 70% or more, for example about 80% or more, and for another example about 90%. In the organic photoelectric device 100, when light enters from the first electrode 10 and/or second electrode 20, and when the active layer 30 absorbs light in a desired and/or alternatively predetermined wavelength region, excitons may be produced from the inside. The excitons are separated into holes and electrons in the active layer 30, and the separated holes are transported to an anode that is one of the first electrode 10 and the second electrode 20 and the separated electrons are transported to the cathode that is the other of and the first electrode 10 and the second electrode 20 so as to flow a current in the organic photoelectric device. Hereinafter, an organic photoelectric device according to another example embodiment is described with reference to FIG. 2. FIG. 2 is a cross-sectional view showing an organic photoelectric device according to another example embodiment. Referring to FIG. 2, an organic photoelectric device 200 according to the present embodiment includes a first electrode 10 and a second electrode 20 facing each other, and an active layer 30 between the first electrode 10 and the second electrode 20, like the above embodiment. However, the organic photoelectric device 200 according to the present embodiment further includes charge auxiliary layers 40 and 45 between the first electrode 10 and the active layer 30, and the second electrode 20 and the active layer 30, unlike the above embodiment. The charge auxiliary layers 40 and 45 may facilitate the transfer of holes and electrons separated from the active layer 30, so as to increase efficiency. The charge auxiliary layers 40 and 45 may be at least one selected from a hole injection layer (HIL) for facilitating hole injection, a hole transport layer (HTL) for facilitating hole transport, an electron blocking layer (EBL) for preventing electron transport, an electron injection layer (EIL) for facilitating electron injection, an electron transport layer (ETL) for facilitating electron transport, and a hole blocking layer (HBL) for preventing hole transport. The charge auxiliary layers 40 and 45 may include, for example, an organic material, an inorganic material, or an organic/inorganic material. The organic material may be an organic compound having hole or electron characteristics, and the inorganic material may be, for example, a metal oxide such as molybdenum oxide, tungsten oxide, nickel oxide, and the like. The hole transport layer (HTL) may include one selected from, for example, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), polyarylamine, poly(N-vinylcarbazole), polyaniline, polypyrrole, N,N,N′,N′-tetrakis(4-methoxyphenyl)-benzidine (TPD), 4-bis[N-(1-naphthyl)-N-phenyl-amino]biphenyl (α-NPD), m-MTDATA, 4,4′,4″-tris(N-carbazolyl)-triphenylamine (TCTA), and a combination thereof, but is not limited thereto. The electron blocking layer (EBL) may include one selected from, for example, poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS), polyarylamine, poly(N-vinylcarbazole), polyaniline, polypyrrole, N,N,N′,N′-tetrakis(4-methoxyphenyl)-benzidine (TPD), 4,4′-bis[N-(1-naphthyl)-N-phenyl-amino]biphenyl (α-NPD), m-MTDATA, 4,4′,4″-tris(N-carbazolyl)-triphenylamine (TCTA), and a combination thereof, but is not limited thereto. The electron transport layer (ETL) may include one selected from, for example, 1,4,5,8-naphthalene-tetracarboxylic dianhydride (NTCDA), bathocuproine (BCP), LiF, Alq3, Gaq3, Inq3, Znq2, Zn(BTZ)2, BeBq2, and a combination thereof, but is not limited thereto. The hole blocking layer (HBL) may include one selected from, for example, 1,4,5,8-naphthalene-tetracarboxylic dianhydride (NTCDA), bathocuproine (BCP), LiF, Alq3, Gaq3, Inq3, Znq2, Zn(BTZ)2, BeBq2, and a combination thereof, but is not limited thereto. Either one of the charge auxiliary layers 40 and 45 may be omitted. The organic photoelectric device may be applied to various fields, for example a solar cell, an image sensor, a photo-detector, a photo-sensor, and an organic light emitting diode (OLED), but is not limited thereto. Hereinafter, an example of an image sensor including the organic photoelectric device is described referring to drawings. As an example of an image sensor, an organic CMOS image sensor is described. FIG. 3 is a schematic top plan view showing an organic CMOS image sensor according to an example embodiment, and FIG. 4 is a cross-sectional view showing the organic CMOS image sensor of FIG. 3. Referring to FIGS. 3 and 4, an organic CMOS image sensor 300 according to an example embodiment includes a semiconductor substrate 310 integrated with photo-sensing devices 50B and 50R, a transmission transistor (not shown), a charge storage 55, a lower insulation layer 60, a color filter layer 70, an upper insulation layer 80, and an organic photoelectric device 100. The semiconductor substrate 310 may be a silicon substrate, and is integrated with the photo-sensing device 50, the transmission transistor (not shown), and the charge storage 55. The photo-sensing devices 50R and 50B may be photodiodes. The photo-sensing devices 50B and 50R, the transmission transistor, and/or the charge storage 55 may be integrated in each pixel, and as shown in the drawing, the photo-sensing devices 50B and 50R may be respectively included in a blue pixel and a red pixel and the charge storage 55 may be included in a green pixel. The photo-sensing devices 50B and 50R sense light, the information sensed by the photo-sensing devices may be transferred by the transmission transistor, the charge storage 55 is electrically connected to the organic photoelectric device 100, and the information of the charge storage 55 may be transferred by the transmission transistor. In the drawings, the photo-sensing devices 50B and 50R are, for example, arranged in parallel without limitation, and the blue photo-sensing device 50B and the red photo-sensing device 50R may be stacked in a vertical direction. A metal wire (not shown) and a pad (not shown) are formed on the semiconductor substrate 110. In order to decrease signal delay, the metal wire and pad may be made of a metal having low resistivity, for example, aluminum (Al), copper (Cu), silver (Ag), and alloys thereof, but are not limited thereto. Further, it is not limited to the structure, and the metal wire and pad may be positioned under the photo-sensing devices 50B and 50R. The lower insulation layer 60 is formed on the metal wire and the pad. The lower insulation layer 60 may be made of an inorganic insulating material such as a silicon oxide and/or a silicon nitride, or a low dielectric constant (low K) material such as SiC, SiCOH, SiCO, and SiOF. The lower insulation layer 60 has a trench exposing the charge storage 55. The trench may be filled with fillers. A color filter layer 70 is formed on the lower insulation layer 60. The color filter layer 70 includes a blue filter 70B formed in the blue pixel and selectively transmitting blue light and a red filter 70R formed in the red pixel and selectively transmitting red light. In the present embodiment, a green filter is not included, but a green filter may be further included. The color filter layer 70 may be omitted. For example, when the blue photo-sensing device 50B and the red photo-sensing device 50R are stacked in a vertical direction, the blue photo-sensing device 50B and the red photo-sensing device 50R may selectively absorb light in each wavelength region depending on their stack depth, and the color filter layer 70 may not be equipped. The upper insulation layer 80 is formed on the color filter layer 70. The upper insulation layer 80 eliminates a step caused by the color filter layer 70 and smoothens the surface. The upper insulation layer 80 and the lower insulation layer 60 may include a contact hole (not shown) exposing a pad, and a through-hole 85 exposing the charge storage 55 of the green pixel. The organic photoelectric device 100 is formed on the upper insulation layer 80. The organic photoelectric device 100 includes the first electrode 10, the active layer 30, and the second electrode 20 as described above. The first electrode 10 and the second electrode 20 may be transparent electrodes, and the active layer 30 is the same as described above. The active layer 30 selectively absorbs and/or senses light in a green wavelength region and replaces a color filter of a green pixel. When light enters from the second electrode 20, the light in a green wavelength region may be mainly absorbed in the active layer 30 and photoelectrically converted, while the light in the rest of the wavelength regions passes through first electrode 10 and may be sensed in the photo-sensing devices 50B and 50R. As described above, the organic photoelectric devices selectively absorbing and/or sensing light in a green wavelength region are stacked and thereby a size of an image sensor may be decreased and a down-sized image sensor may be realized. As described above, the compound represented by the Chemical Formula 1 may be used as a semiconductor compound, aggregation between compounds in a thin film state is inhibited, and thereby light absorption characteristics depending on a wavelength may be maintained. Thereby, green wavelength selectivity may be maintained, crosstalk caused by unnecessary absorption of other light except a green wavelength region may be decreased and sensitivity may be increased. In FIG. 4, the organic photoelectric device 100 of FIG. 1 is included, but it is not limited thereto, and thus the organic photoelectric device 200 of FIG. 2 may be applied in the same manner. FIG. 5 shows a structure of an image sensor having such a structure, and is a cross-sectional view of an organic CMOS image sensor 400 including the organic photoelectric device 200 in FIG. 2. FIG. 6 is a cross-sectional view showing the organic CMOS image sensor according to another example embodiment. Referring to FIG. 6, the organic CMOS image sensor 500 includes a semiconductor substrate 310 integrated with photo-sensing devices 50B and 50R, a transmission transistor (not shown), a charge storage 55, an insulation layer 80, and an organic photoelectric device 100, like the example embodiment illustrated in FIG. 5. However, the organic CMOS image sensor 500 according to the example embodiment illustrated in FIG. 6 includes the blue photo-sensing device 50B and the red photo-sensing device 50R that are stacked and does not include a color filter layer 70, unlike the example embodiment illustrated in FIG. 5. The blue photo-sensing device 50B and the red photo-sensing device 50R are electrically connected with the charge storage 55, and the information of the charge storage 55 may be transferred by the transmission transistor (not shown). The blue photo-sensing device 50B and the red photo-sensing device 50R may selectively absorb light in each wavelength region depending on a stack depth. As described above, the organic photoelectric devices selectively absorbing and/or sensing light in a green wavelength region are stacked and the red photo-sensing device and the blue photo-sensing device are stacked, and thereby a size of an image sensor may be decreased and a down-sized image sensor may be realized. As described above, the organic photoelectric device 100 has improved green wavelength selectivity, and crosstalk caused by unnecessary absorption light in a wavelength region except green may be decreased while increasing sensitivity. In FIG. 6, the organic photoelectric device 100 of FIG. 1 is included, but it is not limited thereto, and thus the organic photoelectric device 200 of FIG. 2 may be applied in the same manner. FIG. 7 is a schematic view showing an organic CMOS image sensor according to another example embodiment. Referring to FIG. 7, the organic CMOS image sensor according to the present embodiment includes a green photoelectric device (G) selectively absorbing and/or sensing light in a green wavelength region, a blue photoelectric device (B) selectively absorbing light in a blue wavelength region, and a red photoelectric device (R) selectively absorbing and/or sensing light in a red wavelength region that are stacked. In the drawing, the red photoelectric device (R), the blue photoelectric device (B), and the green photoelectric device (G) are sequentially stacked, but the stack order may be changed without limitation. The green photoelectric device (G) may be the above organic photoelectric device 100, the blue photoelectric device (B) may include electrodes facing each other and an active layer interposed therebetween and including an organic material selectively absorbing light in a blue wavelength region, and the red photoelectric device (R) may include electrodes facing each other and an active layer interposed therebetween and including an organic material selectively absorbing light in a red wavelength region. As described above, the organic photoelectric device (G) selectively absorbing and/or sensing light in a green wavelength region, the organic photoelectric device (B) selectively absorbing and/or sensing light in a blue wavelength region, and the organic photoelectric device (R) selectively absorbing and/or sensing light in a red wavelength region are stacked, and thereby a size of an image sensor may be decreased and a down-sized image sensor may be realized. The image sensor absorbs light in an appropriate wavelength region and may show all improved sensitivity (YSNR10) and color reproducibility (ΔEab) despite a stack structure. Herein, the YSNR10 indicates sensitivity of the image sensor, which is measured in a method described in Juha Alakarhu's “Image Sensors and Image Quality in Mobile Phones” printed in 2007 International Image Sensor Workshop (Ogunquit Me., USA) but minimum illuminance expressed by lux at a ratio of 10 between signal and noise. Accordingly, the smaller the YSNR10 is, the higher sensitivity is. On the other hand, the color reproducibility (ΔEab) shows a difference from standard colors in an X-Rite chart and the ΔEab is defined as a distance between two points on a Lab color space by CIE (Commission International de L'Eclairage) in 1976. For example, the color difference may be calculated according to Equation 1.ΔE=√{square root over ((ΔL)2+(Δa)2+(Δb)2)} In Equation 1, ΔL denotes a change of a color coordinate L* compared with the color coordinate Lat room temperature (about 20° C. to about 25° C.), Δa denotes a change of a color coordinate a* compared with the color coordinate aat room temperature, and Δb denotes a change of a color coordinate b* compared with the color coordinate bat room temperature. In order to manufacture an image sensor having high color reproducibility at high sensitivity, YSNR10≤100 lux at ΔEab≤3, and herein, the compound may realize YSNR10≤100 lux of sensitivity and color reproducibility at ΔE*ab≤3. The image sensor may be applied to various electronic devices, for example, a mobile phone, a digital camera, and the like but is not limited thereto. FIG. 8 is a block diagram of a digital camera including an image sensor according to an embodiment. Referring to FIG. 8, a digital camera 1000 includes a lens 1010, an image sensor 1020, a motor unit 1030, and an engine unit 1040. The image sensor 1020 may be one of image sensors according to embodiments shown in FIGS. 2 to 7. The lens 1010 concentrates incident light on the image sensor 1020. The image sensor 1020 generates RGB data for received light through the lens 1010. In some embodiments, the image sensor 1020 may interface with the engine unit 1040. The motor unit 1030 may adjust the focus of the lens 1010 or perform shuttering in response to a control signal received from the engine unit 1040. The engine unit 1040 may control the image sensor 1020 and the motor unit 1030. The engine unit 1040 may be connected to a host/application 1050. Hereinafter, the embodiments are illustrated in more detail with reference to examples. However, these examples are non-limiting, and the present disclosure is not limited thereto. 2-iodoselenophene (Compound (i)) is synthesized in a method described in Efficient Synthesis of 2-lodo and 2-Dicyanomethyl Derivatives of Thiophene, Selenophene, Tellurophene and Thieno[3,2-b]thiophene, Takahashi, K.; Tarutani, S. Heterocycles 1996, 43, 1927-1935. 13.6 g (52.8 mmol) of 2-iodoselenophene and 10.0 g (40.6 mmol) of 10H-phenoselenazine are heated and refluxed in 100 ml of anhydrous toluene under presence of 5 mol % of Pd(dba)2, 5 mol % of P(tBu)3, and 4.29 g (44.7 mmol) of NaOtBu for 2 hours. A product therefrom is separated and purified through silica gel column chromatography (toluene:hexane in a volume ratio of 1:4) to obtain 6.89 g of Compound (ii) (10-(selenophen-2-yl)-10H-phenoselenazine, a yield: 45.2%). 2.2 ml of chloridephosphoryl(phosphoryl chloride) is added in a dropwise fashion to 6.8 ml of N,N-dimethylformamide at −15° C. and then, stirred at room temperature (24° C.) for 2 hours. A resultant therefrom is slowly added in a dropwise fashion to a mixture of 180 ml of dichloromethane and 6.84 g of Compound (ii) at −15° C. and then, stirred at room temperature for 30 minutes and concentrated under a reduced pressure. Subsequently, 100 ml of water is added thereto, an aqueous sodium hydroxide solution is also added thereto until pH becomes 14, and the obtained mixture is stirred at room temperature (24° C.) for 2 hours. An organic layer is extracted therefrom with ethyl acetate and washed by an aqueous sodium chloride solution and then, dried by adding anhydrous magnesium sulfate thereto. A product obtained therefrom is separated and purified through silica gel column chromatography (hexane:dichloromethane in a volume ratio of 3:2) to obtain 5.16 g of Compound (1-2) (5-(10H-phenoselenazin-10-yl)selenophene-2-carbaldehyde, a yield: 70.4%). Compound (1-1) (2-benzothiazoleacetonitrile, 1.00 g, 5.74 mmol) and Compound (1-2) are suspended in ethanol under a nitrogen atmosphere. Piperidine (0.59 g, 6.89 mmol) is added thereto, and the mixture is stirred at 60° C. for 12 hours. The obtained mixture is cooled down to room temperature (24° C.), and a solid precipitate therein is washed with ethanol. The solid is heated and dissolved in chloroform, hexane is added thereto, and the obtained mixture is cooled down to room temperature. A precipitate therein is dried to obtain Compound 1 (1.94 g, a yield: 60%). MS (m/z); 560.93[M+H]+ Compound (1-1) (2-benzothiazoleacetonitrile, 1.00 g, 5.74 mmol) and Compound (1-2D) are suspended in ethanol under an nitrogen atmosphere. Piperidine (0.59 g, 6.89 mmol) is added thereto, and the obtained mixture is stirred at 60° C. for 12 hours. The resultant is cooled down to room temperature, and a solid precipitate therein is filtered and washed with ethanol. The solid is heated and dissolved in chloroform, hexane is added thereto, and the obtained mixture is cooled down to room temperature. A solid precipitate therein is dried to obtain Compound 2 (2.25 g, a yield of 70%). MS (m/z); 561.94[M+H]+ Compound (3-1) (3-iodonaphtalen-2-amine, 1.00 g, 3.72 mmol), copper iodide (0.21 g, 1.11 mmol), potassium carbonate (1.02 g, 7.44 mmol), and dimethylsulfoxide (DMSO, 37 ml) are put in a reaction vessel, after argon gas is substituted for gas therein, and then, stirred. Subsequently, Compound (3-2) (benzoylthiocyanate, 1.81 g, 11.15 mmol) is added thereto, and the obtained mixture is stirred at 90° C. for 12 hours. The resultant is cooled down to room temperature, water is added thereto, the obtained mixture is cooled down to room temperature, and water is added thereto, an organic layer is extracted therefrom with ethyl acetate and dried with anhydrous sodium sulfate, and a solvent therein is distilled under a reduced pressure and removed. A residue therefrom is purified through silica gel column chromatography (hexane:ethyl acetate in a volume ratio of 5:1) to obtain Compound (3-3) (N-(naphtho[2,3-d]thiazol-2-yl)benzamide, 0.60 g). This solid is dissolved in methanol (35 ml). Then, 10 ml of a 2N sodium hydroxide aqueous solution is added thereto, and the obtained mixture is heated and stirred for one night. Subsequently, 100 ml of water is added thereto, and a solid precipitate therein is filtered and obtained. The solid is twice washed with water (30 ml) and dried to obtain Compound (3-4) (naphtho[2,3-d]thiazole-2-amine(naphtho[2,3-d]thiazol-2-amine, 0.26 g, a yield of 35%). 1H NMR (300 MHz, CDCl 3): δ 8.05 (s, 1H), 7.94 (s, 1H), 7.88 (d, 1H), 7.81 (d, 1H), 7.36-7.49 (m, 2H), 5.37 (bs, 2H). Dried copper chloride (II) (0.65 g, 4.79 mmol) and isoamyl nitrite (0.70 g, 5.99 mmol) are added to acetonitrile (20 mL) under an argon atmosphere at room temperature, and an acetonitrile solution (60 mL) of Compound (3-4) (naphtho[2,3-d]thiazole-2-amine, 0.80 g, 3.99 mmol) is added thereto at room temperature. The obtained mixture is heated at 65° C. and stirred at the same temperature under an argon atmosphere for 4 hours. The reaction mixture is cooled down to room temperature, 2 M HCl (10 mL) is added thereto, and an organic layer is three times extracted therefrom with chloroform (50 mL). The organic layer is dried with anhydrous sodium sulfate, and a solvent therein is distilled under a reduced pressure and removed. A residue obtained therefrom is purified through silica gel column chromatography (hexane:ethyl acetate in a volume ratio of 2:1) to obtain Compound (3-5) (2-chloronaphtho[2,3-d]thiazole, 0.36 g, a yield of 40%). 1H NMR (300 MHz, CDCl3); δ 8.43 (s, 1H), 8.25 (s, 1H), 8.01 (d, 1H), 7.91 (d, 1H), 7.51-7.56 (m, 2H). Cyanoacetic acid t-butylester (0.308 g, 2.18 mmol) is dissolved in a dimethyl formamide (DMF) solution (5 ml). The obtained solution is little by little added to a 60% sodium hydride (0.11 g, 2.73 mmol) at 0° C., and the obtained mixture is stirred for 10 minutes. Subsequently, Compound (3-5) (2-chloronaphtho[2,3-d]thiazole, 0.40 g, 2.18 mmol) is added to a DMF solution (5 ml), and the obtained mixture is stirred at room temperature for 15 minutes and subsequently, at 120° C. for 2 hours. Then, a 1N hydrochloric acid aqueous solution is added thereto, and an organic layer is extracted therefrom with ethyl acetate therefrom. The organic layer is washed with water and dried with anhydrous sodium sulfate and then, concentrated under a reduced pressure. A residue therein is washed with hexane, a solid obtained therefrom is added to toluene (10 ml), p-toluenesulfonic acid monohydrate (0.10 g) is added thereto, and the obtained mixture is stirred at 100° C. for 3 hours. Then, ethyl acetate is added thereto, and the reaction solution is neutralized by adding a saturated carbonate hydrogen sodium aqueous solution thereto. An organic layer therefrom is dried with anhydrous sodium sulfate and then, concentrated under a reduced pressure. A residue therefrom is purified through silica gel column chromatography (hexane:ethyl acetate in a volume ratio of 3:1) to obtain Compound (3-6) (2-(naphtho[2,3-d]thiazol-2-yl)acetonitrile, 0.25 g, a yield of 46%). 1H NMR (300 MHz, CDCl3); δ 8.54 (s, 1H), 8.38 (s, 1H), 8.05 (d, 1H), 7.94 (d, 1H), 7.52-7.57 (m, 2H), 4.28 (s, 2H). 2-(naphtho[2,3-d]thiazol-2-yl)acetonitrile (0.25 g, 1.11 mmol) and Compound (1-2) are suspended in ethanol under a nitrogen atmosphere. Subsequently, piperidine (0.11 g, 1.34 mmol) is added thereto, and the obtained mixture is stirred at 60° C. for 12 hours. The resultant is cooled down to room temperature, and a solid precipitate therein is filtered and washed with ethanol. The solid is heated and dissolved in chloroform, hexane is added thereto, and the obtained mixture is cooled down to room temperature. Then, a solid precipitate therein is filtered and dried to obtain Compound 3 (0.38 g, a yield of 56%). MS (m/z); 611.99[M+H]+ Compound (3-6) (2-(naphtho[2,3-d]thiazol-2-yl)acetonitrile, 1.00 g, 5.74 mmol) and Compound (1-2D) are suspended in ethanol under a nitrogen atmosphere. Piperidine (0.59 g, 6.89 mmol) is added thereto, and the obtained mixture is stirred at 60° C. for 12 hours. The resultant is cooled down to room temperature, and a solid precipitate therein is filtered and washed with ethanol. The solid is heated and dissolved in chloroform, hexane is added thereto, and the obtained mixture is cooled down to room temperature. Subsequently, a solid precipitate therein is filtered and dried to obtain Compound 4 (2.43 g, a yield of 69%). Compound (5-1) (2-(6-(trifluoromethyl)benzo[d]thiazol-2-yl)acetonitrile, 1.00 g) and Compound (1-2D) are suspended in ethanol under an nitrogen atmosphere. Piperidine (0.59 g, 6.89 mmol) is added thereto, and the obtained mixture is stirred at 60° C. for 12 hours. The resultant is cooled down to room temperature, and a solid precipitate therein is filtered and washed with ethanol. The solid is heated and dissolved in chloroform, hexane is added thereto, and the obtained mixture is cooled down to room temperature. A solid precipitate therein is dried to obtain Compound 5 (2.25 g, a yield of 70%). MS (m/z); 0.43 g>99.99(97.24+2.76)% 2-iodoselenophene is synthesized in a method described in Efficient Synthesis of 2-lodo and 2-Dicyanomethyl Derivatives of Thiophene, Selenophene, Tellurophene and Thieno[3,2-b]thiophene, Takahashi, K.; Tarutani, S. Heterocycles 1996, 43, 1927-1935. 13.6 g (52.8 mmol) of 2-iodoselenophene and 10.0 g (40.6 mmol) of 10H-phenoselenazine is heated and refluxed in 100 ml of anhydrous toluene under presence of 5 mol % of Pd(dba)2, 5 mol % of P(tBu)3, and 4.29 g (44.7 mmol) of NaOtBu for 2 hours. A product obtained therefrom is separated and purified through silica gel column chromatography (toluene:hexane in a volume ratio of 1:4) to obtain Compound (6-2) (10-(selenophen-2-yl)-10H-phenoselenazine, 6.89 g, a yield of 45.2%). 2.2 ml of phosphoryl chloride is added in a dropwise fashion in 6.8 ml of N,N-dimethylformamide at −15° C. and then, stirred at room temperature (24° C.) for 2 hours. The resultant is slowly added in a dropwise fashion to a mixture of 180 ml of dichloromethane and 6.84 g of Compound (6-2) at −15° C., and the obtained mixture is stirred at room temperature (24° C.) for 30 minutes and concentrated under a reduced pressure. Subsequently, 100 ml of water is added thereto, an aqueous sodium hydroxide solution is added thereto until pH becomes 14, and the obtained mixture is stirred at room temperature for 2 hours. Then, an organic layer is extracted therefrom with ethyl acetate, washed with aqueous sodium chloride, and then, dried by adding anhydrous magnesium sulfate thereto. A product obtained therefrom is separated and purified through silica gel column chromatography (hexane:dichloromethane in a volume ratio of 3:2) to obtain Compound (6-3) (5-(10H-phenoselenazin-10-yl)selenophene-2-carbaldehyde, 5.16 g, a yield: 70.4%). 2.00 g (4.96 mmol) of Compound (6-3) is suspended in ethanol, 1.46 g (7.44 mmol) of 1H-cyclopenta[b]naphthalene-1,3(2H)-dione is added thereto, and the obtained mixture is reacted at 50° C. for 2 hours to obtain Compound 6 (2.62 g, a yield: 72.4%). Compound 6 is sublimated and purified up to 99.8%. 1H NMR ppm (DMSO) 8.34 (s)-1H, 8.32 (s)-1H, 8.27 (s)-1H, 8.24-8.16 (m)-3H, 7.98 (dd)-2H, 7.88 (dd)-2H, 7.71 (m)2H, 7.61 (t)-2H, 7.45 (t)-2H, 6.61 (d)-1H Compound 7 is synthesized according to Reaction Scheme 7 in the same method as Reference Synthesis Example 1 by using Compound (7-3) instead of Compound (6-3). 2-iodoselenophene is synthesized in a method described in Efficient Synthesis of 2-lodo and 2-Dicyanomethyl Derivatives of Thiophene, Selenophene, Tellurophene and Thieno[3,2-b]thiophene, Takahashi, K.; Tarutani, S. Heterocycles 1996, 43, 1927-1935. 4.8 g (17 mmol) of 2-iodoselenophene and 2.72 g (13 mmol) of 9,10-dihydro-9,9-dimethylacridine) are heated and refluxed for 2 hours in 25 ml of anhydrous toluene under presence of 5 mol % of Pd(dba)2, 5 mol % of P(tBu)3, and 1.37 g (14.3 mmol) of NaOtBu. A product obtained therefrom is separated and purified through silica gel column chromatography (toluene:hexane in a volume ratio of 1:4) to obtain 0.68 g of Compound (8-2) (9,9-dimethyl-10-(selenophen-2-yl)-9,10-dihydroacridine, 2.5 g, a yield: 57%). 0.85 ml of phosphoryl chloride is added in a dropwise fashion to 2.64 ml of N,N-dimethylformamide at −15° C., and the mixture is stirred at room temperature (24° C.) for 2 hours. The resultant is slowly added in a dropwise fashion to a mixture of 50 ml of dichloromethane and 2.40 g of Compound (8-2) at −15° C., and the obtained mixture is stirred at room temperature (24° C.) for 30 minutes and concentrated under a reduced pressure. Subsequently, 5 ml of water is added thereto, a sodium hydroxide aqueous solution is also added thereto until pH becomes 14, and the mixture is stirred at room temperature (24° C.) for 2 hours. An organic layer extracted therefrom with ethyl acetate was washed with a sodium chloride aqueous solution and dried with anhydrous magnesium sulfate. A product obtained therefrom is separated and purified through silica gel column chromatography (hexane:dichloromethane in a volume ratio of 3:2) to obtain 0.48 g of Compound (8-3) (5-(9,9-dimethylacridin-10(9H)-yl)selenophene-2-carbaldehyde, 1.48 g, a yield: 57%). 0.09 g (0.25 mmol) of Compound (8-3) is suspended in ethanol, 0.05 g (0.29 mmol) of 1,3-dimethyl-2-thiobarbituric acid synthesized according to a method described in J. Pharmacol, 1944, 82, 292, p. 4417 is added thereto, and the mixture is reacted at 50° C. for 2 hours to obtain 0.1 g of Compound 8 (a yield: 99%). Compound 8 is sublimated and purified up to purity of 99.5%. 1H NMR ppm (CDCl3) 8.5 (s)-1H, 7.9 (d)-1H, 7.8 (d)-2H, 7.6 (d)-2H, 7.4 (m)-4H, 7.1 (d)-1H, 3.8 (d)-6H, 1.6 (s)-6H Light Absorption Characteristics of Compounds Each compound according to Synthesis Examples 1 to 5 and C60 are codeposited in a volume ratio of 1:1 to provide each thin film. Light absorption characteristics of each film are evaluated by using an ultraviolet (UV)-visible ray (UV-Vis) with Cary 5000 UV Spectroscopy (Varian Medical Systems). The results are shown in Table 1. TABLE 1λmax (nm)Synthesis Example 1500Synthesis Example 2500Synthesis Example 3520Synthesis Example 4520Synthesis Example 5510 Referring to Table 1, the thin films including the compounds of Synthesis Examples 1 to 5 showed high light absorption characteristics and sufficient wavelength selectivity in a green wavelength region. Deposition Stability of Compounds Each compound according to Synthesis Examples 1 to 5 and Reference Synthesis Examples 1 to 3 is deposited and formed into a thin film, and purity of the thin film is measured regarding deposition stability depending on continuous deposition times. The purity is evaluated by using UPLC (Ultra Performance Liquid Chromatography). The results of Synthesis Example 2 and Reference Synthesis Examples 2 and 3 are shown in Table 2. TABLE 2SynthesisReference SynthesisReference SynthesisExample 2Example 2Example 32nd99.85%99.91%99.30%deposition6th99.94%96.09%89.16%deposition Referring to Table 2, the compound of Synthesis Example 2 shows no purity decrease, even though consecutive deposition times are increased, and thus is not oxidized after the deposition and resultantly, shows excellent deposition stability and oxidation resistance. In other words, the compound according to Synthesis Example 2 is not decomposed despite the repetitive depositions and does not deteriorate performance of a device. On the contrary, the compounds according to Reference Synthesis Examples 2 and 3 show purity deterioration, as consecutive deposition times are increased. As for the compounds according to Reference Synthesis Examples 2 and 3, as the deposition process is repeated, a product decomposed therefrom is increased, deteriorates purity of the compounds and resultantly, performance of a device. Deposition Temperature of Compounds Thermal stability of the compounds according to Synthesis Examples 1 to 5 and Reference Synthesis Examples 1 to 3 is evaluated by measuring a temperature (Ts, a deposition temperature) where 10 wt % thereof is lost at 10 Pa. The loss temperature is measured through a thermogravimetric analysis (TGA). The results of Synthesis Example 2 and Reference Synthesis Example 2 are shown in Table 3. TABLE 3Reference SynthesisSynthesis Example 2Example 2Deposition temperature241° C.276° C. Referring to Table 3, the compound of Synthesis Example 2 has a lower deposition temperature than that of Reference Synthesis Example 2 and thus may be deposited without a decomposition at a low temperature and secure process stability. An about 150 nm-thick anode is formed by sputtering ITO on a glass substrate, and a 100 nm-thick active layer is formed thereon by codepositing a compound represented by Chemical Formula 1 according to Synthesis Example 1 (a p-type semiconductor compound) and C60 (a n-type semiconductor compound) in a thickness ratio of 1:1. Subsequently, a 10 nm-thick molybdenum oxide (MoOx, 0≤x≤3) thin film is formed thereon as a charge auxiliary layer. On the molybdenum oxide thin film, a 7 nm-thick cathode is formed by sputtering ITO, manufacturing an organic photoelectric device (1). An organic photoelectric device (1) is manufactured, and then, organic photoelectric devices (2) to (6) are manufactured according to the same method as that of the organic photoelectric device (1) by using the same deposition equipment. The organic photoelectric devices according to Examples 2 to 5 are manufactured according to the same method as Example 1 except for respectively using the compounds according to Synthesis Example 2 to 5 instead of the compound according to Synthesis Example 1. Likewise, the organic photoelectric devices are respectively manufactured by six times performing a deposition process. Each organic photoelectric device according to Reference Examples 1 to 3 is manufactured according to the same method as Example 1 by respectively using the compounds according to Reference Synthesis Examples 1 to 3 instead of the compound according to Synthesis Example 1. Likewise, the six organic photoelectric devices are respectively manufactured by consecutively six times performing a deposition process. External Quantum Efficiency (EQE) of Organic Photoelectric Devices The organic photoelectric devices according to Examples 1 to 5 and Reference Examples 1 to 3 are evaluated regarding external quantum efficiency (EQE), a dark current (DC), and response time (lag time) depending on the times of deposition. The external quantum efficiency and the dark current are measured by using an IPCE measurement system (McScience Inc., Korea). First, EQE and the dark current of the organic photoelectric devices according to Examples 1 to 5 and Reference Examples 1 to 3 are measured in a wavelength region ranging from about 350 to about 750 nm after calibrating the equipment with a Si photodiode (Hamamatsu Photonics K.K., Japan) and mounting the organic photoelectric devices on the equipment. The response time (lag time) of the organic photoelectric devices according to Examples 1 to 5 and Reference Examples 1 to 3 is evaluated by using incident LED light having a middle wavelength of 530 nm from an upper electrode (a cathode), applying it with electric intensity of 3 V/100 nm to the organic photoelectric devices, and measuring an after-image current 0.1 second later after turning off the LED light. The results of Example 2 and Reference Examples 2 and 3 are shown in Table 4. TABLE 4DepositionEQEDCResponsenumber(%)(h/s)time (msec)Synthesis1st53.2182Example 26th56.5191(Compound 2)Reference1st65.03110Synthesis6th18.65848Example 2(Compound 6)Reference1st64.34650Synthesis5thimmea-immea-immea-Example 3surablesurablesurable(Compound 7) Referring to Table 4, the compound according to Synthesis Example 2 shows no deterioration of EQE and dark current characteristics and also maintains an excellent response speed, even though deposition times are increased. On the contrary, the compound according to Reference Synthesis Example 2 shows sharply-deteriorated EQE and response speed and also, deteriorated dark current characteristics, as the deposition times are increased. On the other hand, the compound according to Reference Synthesis Example 3 is almost decomposed at the 5th deposition and thus no longer deposited. While this disclosure has been described in connection with what is presently considered to be practical example embodiments, it is to be understood that inventive concepts are not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
	description	1. Field of the Invention This invention pertains in general to nuclear reactor fuel assemblies and more particularly to a pressurized water reactor nuclear fuel assembly instrumentation thimble. 2. Background A typical pressurized water reactor includes a reactor vessel which contains nuclear fuel, a coolant, typically a water based solution, which is heated by the nuclear fuel, and means for monitoring and controlling the nuclear reaction. The reactor vessel is cylindrical, and is provided with a hemispherical bottom and a hemispherical top which is removable. The hot water coolant solution is conveyed from and returned to the vessel by a reactor coolant system which includes one or more reactor coolant loops (usually three or four loops, depending upon the power generating capacity of the reactor). Each loop includes a pipeline to convey hot water from the reactor vessel to a steam generator, a pipeline to convey the water from the steam generator back to the reactor vessel, and a pump. The steam generator is essentially a heat exchanger which transfers heat from the reactant coolant system to water from a source that is isolated from the reactor coolant system; the resulting steam is conveyed to a turbine to generate electricity. During operation of the reactor, the water in the vessel and coolant system is maintained at a high pressure to keep it from boiling as it is heated by the nuclear fuel. Nuclear fuel is supplied to the reactor in the form of a number of fuel assemblies, that are supported within a reactor core by upper and lower traversely extending core support plates. Conventional designs of fuel assemblies include a plurality of fuel rods and control rod guide thimbles which are hollowed tubes held in an organized array by grids spaced along the fuel assembly length and attached to the control rod guide thimbles. The guide thimbles are structural members which also provide channels for neutron absorber rods, burnable poison rods or neutron source assemblies which are all vehicles for controlling the reactivity of the reactor. Top and bottom nozzles on opposite ends thereof are secured to the guide thimbles; thereby forming an integral fuel assembly. The grids, as is known in the relevant art, are used to precisely maintain the spacing between the fuel rods in the reactor core, resist rod vibration, provide lateral support for the fuel rods and, to some extent, vertically restrain the rods against longitudinal movement. One type of conventional grid design includes a plurality of interleaved straps that together form an egg-crate configuration having a plurality of roughly square cells which individually accept the fuel rods therein. Depending upon the configuration of the control rod guide thimbles, the guide thimbles can either be received in cells that are either sized the same as those that receive the fuel rods therein, or can be received in relatively larger thimble cells defined in the interleaved straps. Typically at least one instrumentation tube is provided that extends through at least one cell, typically the center cell, in each strap and is captured between the top and bottom nozzles. The instrumentation tube, like the control rod guide thimbles, is attached to each of the grid cells through which it passes by a mechanical connection formed by bulging or welding. A number of measuring instruments are employed within the reactor core to promote safety and to permit proper control of the nuclear reaction. Among other instruments, neutron flux detectors are stationarily positioned within the instrumentation tubes within the core for that purpose. For a proper flux reading of the neutron activity within the region of the corresponding fuel assembly it is important that the flux detectors be centrally positioned around the longitudinal axis of the instrumentation tube. Centering of the in-core instrumentation is required to ensure the detector responses are consistent from location to location within the core. One existing instrumentation tube design is illustrated in FIG. 1. FIG. 1 shows the instrumentation tube 10 extending between the upper or top nozzle 12 and the bottom nozzle 14. An in-core instrument 16 extends through the interior of the instrument tube 10 spanning between the top nozzle 12 and lower or bottom nozzle 14. Dimples 18 formed by crimping the instrumentation tube at a number of diametrically opposed points around its circumference, center the in-core instrumentation 16 within the tube 10. Typically the dimples are provided at a number of elevations along the instrumentation tube 10, with subsequent dimples being rotated 90 degrees as shown in the top section of the instrumentation tube 10 shown in FIG. 2. However the dimples preclude the bulging of the instrumentation tube to a spacer grid at the dimple elevations and also are limited in their ability to center smaller outside diameter in-core instrumentation within the instrumentation tube. Accordingly, a new instrumentation tube design is desired that will center the in-core instrumentation while providing a smooth wall, non dimpled, outside circumference that may be either welded or bulged to the spacer grids. Furthermore, it is an object of this invention to provide such an in-core instrumentation tube that can center any size in-core instrumentation within the instrumentation tube. The foregoing objects are achieved by an improved nuclear fuel assembly having a top nozzle, a bottom nozzle and a plurality of elongated control rod guide thimbles respectively attach at a first end to the top nozzle and at a second end to the bottom nozzle. A plurality of elongated fuel rods supporting fissile material there within extend parallel to the control rod guide thimbles, between the top nozzle and the bottom nozzle. A plurality of traversed grids are arranged in a spaced tandem array between the top nozzle and the bottom nozzle. The grids respectively form a lattice to latterly support the fuel rods in a spaced orderly array. The grids are attached to and are supported axially by the control rod guide thimbles. At least one elongated instrumentation tube extends and is captured between the top nozzle and the bottom nozzle. The control rod guide thimbles, fuel rods and the instrumentation tube have parallel axes extending along their elongated dimension. The instrumentation tube is adapted to receive an in-core instrumentation that extends along a substantial axial length of the instrumentation tube. The in-core instrumentation remains fixed during reactor operation. An instrumentation tube insert extends within and substantially along the elongated dimension of the instrumentation tube. The insert has an inside narrow most diameter at a plurality of axial locations along the length of the insert that closely approximates the outside diameter of the in-core instrumentation so as to maintain the in-core instrumentation centered in the instrumentation tube. The inside narrow most diameter is supported at a fixed distance from an inside diameter of the instrumentation tube at spaced segmented locations along the interior of the instrumentation tube. The insert is adaptable to center in-core instrumentation with the smallest practical outside diameter without substantially increasing the neutron capture cross section of the instrumentation tube. In one embodiment the insert is a spiral spring that has an outside diameter that closely matches the inside diameter of the instrumentation tube and an inside diameter that substantially closely matches the outside diameter of the in-core instrumentation. Desirably the spring has a closed pitch at each end and an appropriate pitch to preclude snagging of the In-Core Instrument, e.g., a pitch of approximately 1″ (2.54 cm), in an intermediate region below and above both end portions of the spring. In another embodiment, the inside diameter of the spring circumscribes the outside diameter of an instrumentation thimble tube that has an inside diameter which substantially matches the outside diameter of the in-core instrumentation. The instrument thimble tube extends within the spring spanning the length of the instrumentation tube. In another embodiment the instrumentation thimble tube is flared outward at its lower end towards the wall of the instrumentation tube to retain the spring between the instrument thimble tube and the instrumentation tube. In another embodiment the insert has an oval cross section at a plurality of locations along its axial dimension. The major outside diameter of the oval cross section approximates the inside diameter of the instrumentation tube and the minor inside diameter of the oval cross section substantially approximates the outside diameter of the in-core instrumentation. Desirably, the oval cross section is rotated relative to the axis of the instrumentation tube at different elevations along the axial length of the instrumentation tube. Desirably, the rotation is 90 degrees between adjacent oval cross sections. Referring now to the drawings and particularly to FIG. 3, there is shown an elevational view of a nuclear reactor fuel assembly, represented in vertically shorten form and being generally designated by reference character 20. The fuel assembly 20 is the type used in a pressurized water reactor and has a structural skeleton which, at its lower end, includes a bottom nozzle 14. The bottom nozzle 14 supports the fuel assembly 20 on a lower core support plate 22 in the core region of the nuclear reactor (not shown). In addition to the bottom nozzle 14, the structural skeleton of the fuel assembly 20 also includes a top nozzle 12 at its upper end and a number of guide tubes or thimbles 24, which extend longitudinally between the bottom and top nozzles 14 and 12 and at the opposite ends are rigidly attached thereto. The fuel assembly 20 further includes a plurality of traverse grids 26, that are axially spaced along, and mounted to, the guide thimble tubes 24 and an organized array of elongated fuel rods 28 traversely spaced and supported by the grids 26. Also, the fuel assembly 20 includes an instrumentation tube 10 located in the center thereof, which extends and is captured between the bottom and top nozzles 14 and 12. With such an arrangement of parts, fuel assembly 20 forms an integral unit capable of being conveniently handled without damaging the assembled parts. As mentioned above, the fuel rods 28 in the array shown in the assembly 20 are held in space relationship with one another by the grids 26 spaced along the fuel assembly length. Each fuel rod 28 includes nuclear fuel pellets 30 and is closed at its opposite ends by upper and lower end plugs 32 and 34. The pellets 30 are maintained in a stack by plenum spring 36 dispose between the upper end plug 32 and the top of the pellet stack. The fuel pellets 30, composed of a fissel material, are responsible for creating the reactive power of the reactor. A liquid moderator/coolant such as water or water containing boron, is pumped upwardly through a plurality of flow openings in the lower core plate 22 to the fuel assembly. The bottom nozzle 14 of the fuel assembly 20 passes the coolant upwardly through the guide tubes 24 and along the fuel rods 28 of the assembly in order to extract heat generated therein for the production of useful work. To control the fission process, a number of control rods 38 are recipically movable in the guide thimbles 24 located at predetermined positions in the fuel assembly 20. Specifically, a rod cluster control mechanism 40 positioned above the top nozzle 12 supports the control rods 38. The control mechanism has an internally threaded cylindrical member 42 which functions as a drive rod, with a plurality radially extending flukes or arms 44. Each arm 44 is interconnect to control rod 38 such that the control rod mechanism 40 is operable to move the control rods vertically in the guide thimbles 24 to thereby control the fission process in the fuel assembly 20, all in a well known manner. The grids 26 are mechanically attached to the control rod guide thimbles 24 and the instrumentation tube 10 by welding, or preferably by bulging. Bulging is particularly desirable where welding dissimilar materials is difficult. As previously mentioned with regards to FIG. 1 the prior art configuration for centering the in-core instrumentation employing dimples made it difficult to fasten the instrumentation tube 10 to the grids 26 at the dimple elevations. This was particularly true at the lower most grid 26. This invention overcomes this difficulty by providing a smooth wall instrumentation tube that can be readily welded or bulged to make a rigid connection with the grid strap while retaining the capability of centering the in-core instrumentation within the instrumentation tube as will be explained hereafter. A first preferred embodiment of this invention is illustrated in FIG. 4. In accordance with this invention a smooth wall instrumentation tube 10 is provided. In this example an instrumentation tube having an inside diameter of 0.900 inch (2.29 cm) is employed though it should be appreciated that the size of the instrumentation tube may vary from reactor to reactor without impacting on the concept of this invention. A coiled thimble spring 46 is closely received within the inside diameter of the instrumentation tube 10. The thimble spring 46 preferably spans the elongated axial dimension of the instrument tube 10 and is captured between the bottom nozzle 14 and the top nozzle 12. In this example the thimble spring 46 preferably has an outside diameter of 0.860 inch (2.18 cm) and the spring wire diameter is 0.156 inch (0.40 cm). The dimensions of the thimble spring 46 may vary without detracting from the concept of this invention so long as the thimble spring is sized to center the in-core instrument. By being “centered” it means that the in-core instrument centering devices, i.e., the thimble springs, are sized to limit radial movement of the in-core instrument within the instrument tube 10, such that, the functional criterion for the in-core instrument is satisfied. Desirably, the spring has a closed pitch at each end, i.e., adjacent spiral coil turns approximately touch, and a larger pitch, e.g.,1 inch (2.54 cm) pitch, in the central axial region 48, i.e., the coil repeats a 360 degree rotation every pitch of axial length along the instrumentation tube. The size of the pitch may vary and is selected so as to preclude snagging of the In-Core Instrument. The in-core instrumentation 16 is received within the annular, central opening of the thimble spring 46 and spans between the fuel assembly top nozzle 12 and bottom nozzle 14. The diameter of the spring can be changed to accommodate different size in-core instrumentation. Thus, employing the concept of this invention, the walls of the instrumentation tube 10 can be bulged to create a mechanical connection with the grid strap without adversely affecting the centering of the in-core instrumentation. Preferably, the bulging occurs on portions of the inner circumference of the instrumentation tube 10 where the spring is not located or, the bulging process can be performed before the spring is inserted. FIG. 5 is a cross section taken along the mid span of the instrumentation tube 10 that shows the relevant positioning of the instrument tube walls and spring relative to the in-core instrumentation 16. Preferably, the instrument tube is constructed from zircaloy and the spring is construction from stainless steel though it should be appreciated that other reactor core materials may similarly be employed, i.e., relatively high temperature materials having a relatively low neutron capture cross-section that can withstand the reactor core environment. A second embodiment, which is a variation on the embodiment just described with regards to FIGS. 4 and 5 is illustrated in FIGS. 6 and 7. Like reference characters are used for the corresponding components between the two embodiments, though it should be appreciated that the dimensions of some of those components may vary from one embodiment to the other. As stated previously the dimensions are provided merely as an example and are not critical so long as the foregoing criteria are satisfied. The embodiment shown in FIG. 6 includes the same smooth walled instrument tube with an inside diameter of 0.900 inches (2.29 cm) and an outside diameter of 0.980 inches (2.49 cm) that is captured between the top nozzle 12 and bottom nozzle 14 as previously stated with regard to the embodiment shown in FIG. 4. A thimble spring 46 is closely received within the instrumentation tube 10 with a closed pitch at either end and a larger pitch, e.g., 1 inch pitch in the intermediate region as mentioned previously. The spring shown in FIG. 6 has a slightly smaller outside diameter of 0.848 inches (2.15 cm), but as previously mentioned that is not critical. A thimble tube 50 is closely received within the annular opening of the spring and spans the axial length of the instrumentation tube 10 from the top surface of the bottom nozzle to the top end of the instrumentation tube received within the top nozzle 12. The thimble tube is flared at its lower end 52 and captures the thimble spring 46 between the outside surface of the thimble tube 50 and the interior surface of the instrument tube 10. The thimble tube is sized to center the in-core instrument, e.g., an inside diameter of 0.552 inch (1.40 cm) and an outside diameter of 0.626 inch (1.59 cm). The thimble spring 46 is in close proximity to the inner wall of the instrument tube 10 and acts as a spacer between the instrument tube 10 and the thimble tube 50. The thimble tube 50 provides the guide path for the in-core instrumentation 16, which is inserted into the fuel assembly instrument tube 10 from the bottom of the reactor before operation of the reactor is started and is withdrawn before the fuel assembly is moved. In one embodiment the in-core instrumentation thimble assembly 50 is captured between the top and bottom nozzles 12, 14 and may be retained in the instrument tube 10 by preloaded the thimble spring 46 within the instrument tube 10. The thimble tube 50 and thimble spring 46 may be sized to accommodate any size in-core instrumentation. The dimples in the prior art instrument tube previously employed for centering the in-core instrumentation are at their limit and can only center the larger outside diameter designed in-core instruments. Thus, the improvement of this invention can center in-core instruments over any outside diameter range that can be accommodated by the inside diameter of the instrumentation tube and can operate with both bulged and welded instrument tube to fuel rod spacer grid connections. A third embodiment of this invention is illustrated in FIG. 8 and employs an alignment tube 54 that is inserted into a smooth, non dimpled, instrumentation tube 10. The alignment tube 54 contains pairs of ovalized regions 56, 58 that are oriented orthogonally to one another, thereby locally reducing the effective inside diameter (the minor diameter) of the tube 54. The ovalized tube 54 can center the smaller diameter in-core instruments as well as support the preferred bulged instrument tube-to-spacer grid connection. The ovalized regions 56, 58, shown in cross section in FIGS. 8b and 8c, perform the function previously served by the dimples in the prior art instrument tube, i.e., center the in-core instrument within the instrumentation tube. The outside and inside diameters of the alignment insert tube 54 is selected such that when ovalized, the major outside diameter of the oval region would center the tube within the instrumentation tube while the minor diameter would center the in-core instrumentation which is inserted within the alignment tube 54. As with the prior art dimpled design, the use of orthogonal pairs of ovalized sections limits the positioning of the in-core instruments in both orthogonal directions. Use of the ovalized tube offers two distinct advantages over the current dimple design; in that the non dimpled instrumentation tube 10 is compatible with both bulging and welding for attaching the grids 26 to guide thimble tubes 24 and the ovalized tube concept is compatible with smaller in-core instrumentation diameters than can be accommodated by a dimpled instrumentation tube, due to material deformation limitation of the dimples. The ovalization approach does not suffer from the material limitation since the ovalization process induces significantly less strain in the tube for a given effective diameter than the dimple tube concept. Orthogonally oriented pairs of ovalized regions 56, 58 could be located on the same spacing as the current dimples, However, the spacing is not restricted by the spacer grid locations as the dimples are, so there is added flexibility in spacing the ovalized regions. Securing the ovalized alignment tube 54 within the instrumentation tube 10 could be accomplished in a variety of ways including bugling the two tubes together at the top or the bottom, threading the ovalized tube to the lower end fitting via an end plug, or preloading the tube against the top and bottom nozzles with a helical spring which is also contained within the instrumentation tube 10. Accordingly, a number of embodiments have been described, in accordance with this invention, that enable centering of in-core instruments of the narrow-most practical diameter while still enabling a rigid connection between the grid straps and the instrumentation tube by bugling or welding. While the specific embodiments have been described in detail it should be appreciated by those skilled in the art that various other modifications and alternatives to those details could be developed in light of the overall teachings of the disclosure. Accordingly, the particular embodiments disclosed are meant to be illustrative only and not limiting as to the scope of the invention, which is to be given the full breath of the appended claims and any and all equivalence thereof.
	summary

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